Co(5)BP(3)O(14): The First Borophosphate with Planar BO(3) Groups Connected to PO(4) Tetrahedra

Inorganic Chemistry. Nov, 1996  |  Pubmed ID: 11666863

Synthesis, Characterization, and Bonding of Heteroatomic Clusters: Na(13)Cd(20)E(7) (E = Pb, Sn), a Further Example of a Structure Containing Empty Icosahedra Without an Element of Group 13

Inorganic Chemistry. Sep, 1997  |  Pubmed ID: 11670084

The compounds Na(13)Cd(20)E(7) (E = Pb, Sn) were made in nearly 100% yield by quenching the melts of appropriate mixtures of elements sealed in niobium containers. They crystallize in the cubic space group Im&thremacr;, Z = 4, with a = 15.992(2) and 15.790(4) Å for E = Pb and Sn, respectively. The Cd/E part of the structure is a framework of heavily fused monocapped truncated trigonal prisms. Twelve-bonded icosahedra are nested in cavities of the framework. This is the second example of a structure containing empty icosahedra made without the participation of an element of the boron group. The sodium cations occupy the space between the clusters and inside the 13-atom polyhedra.

Synthesis and Structure of the Zintl-Phase K(4)Pb(9) Containing Isolated Pb(9)(4)(-) Clusters of Two Different Geometries

Inorganic Chemistry. Mar, 1998  |  Pubmed ID: 11670346

The first nine-atom deltahedral clusters of lead in the solid state are found in the Zintl-phase K(4)Pb(9). The compound crystallizes in the monoclinic space group P2(1)/m, Z = 4, with a = 9.648(3) Å, b = 13.243(5) Å, c = 15.909(8) Å, and beta = 103.24(4) degrees. The isolated Pb(9)(4)(-) clusters are of two different geometries, a monocapped square antiprism and an elongated tricapped trigonal prism.

Deltahedral Clusters in Neat Solids: Synthesis and Structure of the Zintl Phase Cs(4)Pb(9) with Discrete Pb(9)(4-) Clusters

Inorganic Chemistry. Jul, 1998  |  Pubmed ID: 11670498

Arachno-

Angewandte Chemie (International Ed. in English). Mar, 2001  |  Pubmed ID: 11268100

Synthesis and Characterization of RbLi(7)Ge(8) with Isolated Closo-

Angewandte Chemie (International Ed. in English). Apr, 2001  |  Pubmed ID: 11317317

Synthesis and Characterization of Cs(5)P[Mo(4)O(14)(OH)](2).2H(2)O: a New Molybdophosphate Cluster with Face-sharing MoO(6) Octahedra

Inorganic Chemistry. Jan, 2002  |  Pubmed ID: 11782155

A Reduced Polyoxomolybdenum Borophosphate Anion Related to the Wells-Dawson Clusters

Journal of the American Chemical Society. Feb, 2002  |  Pubmed ID: 11829590

The new compound (C3N2H5)8[MoV5MoVI7O22(BO4)2(PO4)5(HPO4)3].nH2O is the first molybdenum borophosphate. It contains clusters of twelve molybdenum, eight phosphorus and two boron atoms, [Mo12O22(BO4)2(PO4)5(HPO4)3]8- similar to the Wells-Dawson clusters. Five molybdenum atoms are MoV while the others are MoVI, and the five electrons are delocalized. According to the temperature dependence of the magnetic susceptibility four of these electrons are paired.

[Ph(2)Bi-(Ge(9))-BiPh(2)](2-): a Deltahedral Zintl Ion Functionalized by Exo-bonded Ligands

Journal of the American Chemical Society. Mar, 2002  |  Pubmed ID: 11890785

The title anion was synthesized by a reaction of nido-Ge(9)(4-), made from K(4)Ge(9) dissolved in ethylenediamine and 2,2,2-crypt(4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane), with BiPh(3). It was structurally characterized in (K-2,2,2-crypt)(2)[Ge(9)(BiPh(2))(2)].en which was crystallized from the solution. The anion is a monocapped square antiprism of Ge(9) with two diphenylbismuth ligands exo-bonded to opposite vertexes of the open face of the cluster. This is the first example where covalently exo-bonded ligands are attached to a deltahedral cluster that can exist without them as well.

Naked Clusters of 56 Tin Atoms in the Solid State

Journal of the American Chemical Society. Apr, 2002  |  Pubmed ID: 11916421

Isolated, gigantic tin clusters of 56 atoms are discovered in the ternary compound Ba(16)Na(204)Sn(310) (cubic, F(-)43m, Z = 1, a = 25.2041(8) A) made by direct fusion of the elements at 800 degrees C. The cluster, made of four face-fused pentagonal dodecahedra, has 36 pentagonal faces and 90 edges, and resembles a concave fullerene "dented" at four places. It is made of three- and four-bonded tin atoms and is "stuffed" with four barium cations, [Ba(4)@Sn(56)](36-). This is the largest main group naked cluster in the solid state besides the fullerenes. Also occurring in the structure are two other isolated clusters of tin, Sn(16-n) (n = 0, 1, 2, 3, or 4) and Sn(8).

KBa(2)InAs(3) with Coexisting Monomers of [In(2)As(7)](13-) and Their One-dimensional Polymers

Inorganic Chemistry. Apr, 2002  |  Pubmed ID: 11952387

The title compound was made by fusion of a stoichiometric mixture of the pure elements. The structure (orthorhombic, Cmc2(1), Z = 16, a = 10.129(2) A, b = 25.208(4) A, c = 13.884(3) A) is made of isolated units of [In(2)As(7)](13-) and a polymer chain of [In(2)As(5)](7-) made of the same units. According to magnetic measurement, KBa(2)InAs(3) is a closed-shell compound, a Zintl phase.

Niobium-arsenic Zintl Phases: A(6)NbAs(5) (A = K, Rb, Cs), K(6)NbTlAs(4), and K(8)NbPbAs(5) with Edge-bridged Niobium-centered Tetrahedra of Arsenic, [NbAs(4)M](n-) Where M = As, Tl, Pb

Inorganic Chemistry. Jun, 2002  |  Pubmed ID: 12033887

The five title compounds were prepared by direct reactions of the corresponding elements at high temperature. Their structures contain isolated anions of tetrahedral NbAs(4) where one of the edges of the tetrahedron is bridged by a third atom. The bridging atom is arsenic in A(6)NbAs(5) (monoclinic, P2(1)/c, Z = 8; with a = 25.774(3) A, b = 9.335(1) A, c = 13.012(1) A, beta = 101.05(1) degrees for A = K; a = 27.629(1) A, b = 9.925(1) A, c = 14.111(1) A, beta = 101.63(1) degrees for A = Rb; and a = 27.405(1) A, b = 9.9447(6) A, c = 13.9964(8) A, beta = 101.210(1) degrees for A = Cs), thallium in K(6)NbTlAs(4) (orthorhombic, Pnma, Z = 4, a = 18.786(1) A, b = 10.4442(4) A, c = 7.715(1) A), and lead in K(8)NbPbAs(5) (monoclinic, C2/c, Z = 8, a = 31.597(9) A, b = 9.353(1) A, c = 13.427(2) A, beta = 95.25(1) degrees ). The lead atom in the latter is bonded to a third arsenic atom as well. Magnetic measurements showed diamagnetic behavior, and therefore, the compounds are electronically balanced, closed-shell type compounds and can be described as transition-metal Zintl phases. The bonding in the anion NbAs(5)(6-) is discussed in detail.

Synthesis and Characterization of [Mo(7)O(16)(O(3)PCH(2)PO(3))(3)]:(8-) a Mixed-valent Polyoxomolybdenum Diphosphonate Anion with Octahedrally and Tetrahedrally Coordinated Molybdenum

Inorganic Chemistry. Jul, 2002  |  Pubmed ID: 12132930

Two new compounds containing the title diphosphono-polyoxometalate anion and diprotonated ethylenediamine (enH(2)) or piperazine (ppzH(2)) countercations have been hydrothermally synthesized and structurally characterized ((enH(2))(4)[Mo(7)O(16)(O(3)PCH(2)PO(3))(3)].7H(2)O, triclinic, P(-)1, Z = 2, a = 10.3455(7) A, b = 13.136(1) A, and c = 20.216(3) A, alpha = 93.247(6) degrees, beta = 96.434(6) degrees, and gamma = 111.900(6) degrees; (ppzH(2))(4)[Mo(7)O(16)(O(3)PCH(2)PO(3))(3)].8H(2)O, triclinic, P(-)1, Z = 2, a = 13.255(2) A, b = 13.638(2) A, and c = 16.874(4) A, alpha = 93.20(2) degrees, beta = 101.27(2) degrees, and gamma = 105.87(1) degrees). The anion is a ring of three pairs of edge-sharing octahedra of Mo(V)O(6) (with Mo(V)-Mo(V) bonds) that share corners with each other. The diphosphonate groups connect the pairs at the periphery. The ring is "capped" by a tetrahedron of Mo(VI)O(4). According to magnetic measurements, the compounds are diamagnetic.

[Ge(9)=Ge(9)=Ge(9)](6-): a Linear Trimer of 27 Germanium Atoms

Journal of the American Chemical Society. Sep, 2002  |  Pubmed ID: 12224941

The title anion was synthesized by oxidation of nido-Ge94- with Ph3P or Ph3As in ethylenediamine solution. It was structurally characterized in the compound (Rb-2,2,2-crypt)6[Ge9=Ge9=Ge9].3en (2,2,2-crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) crystallized from the solution. The anion is a linear trimer of nine-atom clusters with the shape of tricapped trigonal prisms elongated along two of the three prismatic edges. Each pair of clusters is connected by two exo-bonds.

Synthesis and Characterization of K(38)Nb(7)As(24) and Cs(9)Nb(2)As(6): the First Mixed-valence Transition-metal Zintl Phases

Inorganic Chemistry. Nov, 2002  |  Pubmed ID: 12401102

The two title compounds were prepared by direct reactions of the corresponding elements at high temperature, and their structures were determined from single-crystal X-ray diffraction data. The structure of K(38)Nb(7)As(24) (orthorhombic; Cmcm; Z = 4; a = 10.4974(6), b = 23.915(2), c = 36.046(2) A) comprises isolated tetrahedra of NbAs(4) and two types of dimers of edge-sharing tetrahedra: dimers containing only Nb(V), [Nb(V)2As(6)](8-), and mixed-valence dimers with both Nb(IV) and Nb(V), [Nb(IV)Nb(V)As(6)](9-). The structure of Cs(9)Nb(2)As(6) (orthorhombic; Pbca; Z = 8; a = 17.5848(7), b = 16.940(2), c = 18.183(4) A) contains only the latter dimers. Magnetic measurements showed Curie-Weiss paramagnetic behavior for both compounds consistent with one unpaired electron/mixed-valence dimer. Cs(9)Nb(2)As(6) exhibits also an antiferromagnetic transition at about 36 K. The two compounds are the first mixed-valence (of class III) transition-metal Zintl phases.

Cubane with a Handle: [[In(3)As(4)Nb]-As](7-) in Cs(7)NbIn(3)As(5)

Angewandte Chemie (International Ed. in English). Apr, 2002  |  Pubmed ID: 12491269

Synthesis and Characterization of Transition-metal Zintl Phases: K(10)NbInAs(6) and K(9)Nb(2)As(6)

Inorganic Chemistry. Feb, 2003  |  Pubmed ID: 12562206

The two title compounds were prepared by direct reactions of the corresponding elements at high temperature. The structures were determined by single-crystal X-ray diffraction: K(10)NbInAs(6), monoclinic, P2(1)/n, Z = 2, a = 9.107(1) A, b = 8.2878(8) A, c = 15.139(1) A, beta = 91.112(9) degrees; K(9)Nb(2)As(6), monoclinic, P2(1)/c, Z = 2, a = 9.348(1) A, b = 9.113(1) A, c = 12.798(1) A, beta = 95.98(1) degrees. They contain isolated dimers made of edge-sharing tetrahedra of [NbAs(4)] and [InAs(4)] in the former, NbInAs(6)(10)(-), and only [NbAs(4)] in the latter, Nb(2)As(6)(9)(-). Magnetic measurements show that K(10)NbInAs(6) is diamagnetic, i.e., a d(0) transition-metal Zintl phase, while K(9)Nb(2)As(6) exhibits a Curie-Weiss behavior consistent with the presence of one unpaired electron. The latter defines K(9)Nb(2)As(6) as a mixed-valence (presumably of type III) transition-metal Zintl phase, only the third example of such phases.

[Mo5VMo7VIO30(BPO4)2(O3P-Ph)6]5-: a Phenyl-substituted Molybdenum(V/VI) Boro-phosphate Polyoxometalate

Inorganic Chemistry. Mar, 2003  |  Pubmed ID: 12611535

The title polyanion is the first hybrid borophosphate-phenylphosphonate polyoxometalate. It was structurally characterized as its imidazolium salt, (C(3)N(2)H(5))(5)[Mo(12)O(30)(BPO(4))(2)(O(3)P-Ph)(6)].H(2)O (monoclinic, P2(1)/c, a = 22.120(3) A, b = 13.042(2) A, and c = 32.632(4) A, beta = 101.293(3) degrees ), which was synthesized hydrothermally from imidazole, molybdenum oxide and metal, and boric, phosphoric, and phenylphosphonic acids. The anion is the second example of a new class of polyoxometalates that resemble Dawson anions but where the two pole caps of three edge-sharing MoO(6) octahedra in the latter are replaced by other units, in this case tetrahedral borate sharing corners with three phenylphosphonic groups, [(OB)(O(3)P-Ph)(3)]. The 12 molybdenum atoms forming the two equatorial belts of the cluster are of mixed-valence, five are Mo(V) and seven are Mo(VI), and the resulting five electrons are delocalized. Four of these electrons are paired according to the temperature dependence of the magnetic susceptibility. The new compound is soluble in a mixture of water and pyridine (in equal volumes) as well as in nitromethane, and the anions are intact in these solutions.

[Ge9=Ge9=Ge9=Ge9]8-: a Linear Tetramer of Nine-atom Germanium Clusters, a Nanorod

Inorganic Chemistry. Sep, 2003  |  Pubmed ID: 12971742

A tetramer of nine-atom deltahedral germanium clusters and charge 8-, [Ge9=Ge9=Ge9=Ge9]8- , has been characterized as a (Rb-18C6)(+) salt (18C6 = 18-crown-6 polyether). The clusters are connected by pairs of parallel bonds, and the electrons are delocalized over the whole anion. The size of the tetramer is of nanorod dimensions, ca. 2 nm.

Novel Mixed-valence Heteropolyoxometalates: a Molybdenum Diphosphonate Anion [MoV7MoVIO16(O3PPhPO3H)4]3- and Its One- and Two-dimensional Assemblies

Inorganic Chemistry. Nov, 2003  |  Pubmed ID: 14577801

A novel mixed-valence polyoxomolybdenum anion, [Mo(V)(7)Mo(VI)O(16)(O(3)PPhPO(3)H)(4)](3)(-), was synthesized hydrothermally from molybdenum oxide, molybdenum metal, boric and phosphoric acids, 1,2-phenyldiphosphonic acid, and imidazole (ImH) and was structurally characterized as an imidazolium salt (orthorhombic, Aba2; a = 16.674(4), b = 17.238(1), and c = 24.81(2) A). One- and two-dimensional structures of this anion and additional molybdenum diphosphonate linkers were assembled as well. They were structurally characterized as their pyridinium (pyH) salts (pyH)(4)[[Mo(V)(7)Mo(VI)O(16)(O(3)PPhPO(3))(2)(O(3)PPhPO(3)H)(2)][Mo(2)O(4)(OH)(HO(3)PPhPO(3)H)]].5H(2)O (monoclinic, P2(1)/c; a = 20.8506(9), b = 22.866(1), and c = 21.1403(9) A; beta = 118.7087(8) degrees ) and (pyH)(3)[[Mo(V)(7)Mo(VI)O(16)(O(3)PPhPO(3))(4)][Mo(2)O(2)(OH)(2)(HO(3)PPhPO(3)H)]].3H(2)O (orthorhombic, Pca2(1); a = 19.057(1), b = 20.402(2), and c = 20.660(2) A). The compounds were also characterized by IR spectroscopy and magnetic measurements.

Derivatization of Deltahedral Zintl Ions by Nucleophilic Addition: [Ph-Ge9-SbPh2]2- and [Ph2Sb-Ge9-Ge9-SbPh2]4-

Journal of the American Chemical Society. Nov, 2003  |  Pubmed ID: 14611242

The type of the reactions of addition of exo-bonded groups to deltahedral Zintl ions such as Ge9(n-) has been established as addition of anionic nucleophiles. Various nucleophiles such as Ph2Bi-, Ph2Sb-, Ph- interact with the relatively low-lying LUMO of Ge9(2-) and/or the half filled HOMO of Ge9(3-) and bond to the clusters. The title anions, characterized in their (K-crypt) salts where crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo-[8.8.8]-hexacosane, and the previously characterized [Ph2Sb-Ge9-SbPh2](2-) are made by a reaction of K4Ge9 with SbPh3 in ethylenediamine. [Ph-Ge9-SbPh2](2-) is the first ogranically functionalized deltahedral Zintl ion, i.e., a deltahedral ion with a direct carbon-cluster covalent bond, that can exists without the substituents as well. The Ge(9) clusters resemble tricapped trigonal prisms with one elongated edge (one of the three edges parallel to the pseudo 3-fold axis). The two substituents are always bonded to the vertexes of such an elongated edge. The same is true for the intercluster bond in [Ph2Sb-Ge9-Ge9-SbPh2)](4-).

Synthesis and Characterization of Transition-metal Zintl Phases: Cs24Nb2In12As18 and Cs13Nb2In6As10 with Isolated Complex Anions

Inorganic Chemistry. Dec, 2003  |  Pubmed ID: 14658914

The title compounds were prepared by direct reaction of the corresponding elements at high temperature. Their structures were determined by single-crystal X-ray diffraction (Cs24Nb2In12As18, triclinic, P1, Z=1, a=9.519(4), b=9.540(5), and c=25.16(1) A, alpha=86.87(4), beta=87.20(4), and gamma=63.81(4) degrees; Cs13Nb2In6As10, triclinic, P1, Z=1, a=9.5564(5), b=9.6288(5), and c=13.9071(7) A, alpha=83.7911(8), beta=80.2973(8), and gamma=64.9796(8) degrees). Cs24Nb2In12As18 and Cs13Nb2In6As10 contain isolated anions of [Nb2In12As18](24-) and [Nb2In6As10](13-), respectively. Each anion includes two cubane-like units made of one niobium, three indium, and four arsenic corners where a fifth arsenic atom completes the tetrahedral coordination at niobium, [(NbAs)In3As4]. In Cs13Nb2In6As10 these two units are connected via a direct In-In bond between two indium vertexes of the cubanes. In Cs24Nb2In12As18, on the other hand, the same two units are linked by a dimer made of semicubanes of [In3As4], i.e., a cubane with one missing vertex. Magnetic measurements show that Cs24Nb2In12As18 is diamagnetic, i.e., a d0 transition-metal Zintl phase, while Cs13Nb2In6As10 exhibits a Curie-Weiss behavior that corresponds to one unpaired electron.

Naked Deltahedral Silicon Clusters in Solution: Synthesis and Characterization of Si9(3-) and Si5(2-)

Journal of the American Chemical Society. Jun, 2004  |  Pubmed ID: 15174843

Elusive for over 100 years, deltahedral Zintl ions of silicon are finally synthesized and structurally characterized. The two clusters reported here, Si93- and Si52-, are analogous to known clusters of the heavier members of this group: Ge, Sn, and Pb.

Synthesis, Characterization, and Electronic Structure of Ba5In4Bi5: an Acentric and One-electron Deficient Phase

Chemistry (Weinheim an Der Bergstrasse, Germany). Aug, 2004  |  Pubmed ID: 15281144

The new ternary phase Ba(5)In(4)Bi(5) was synthesized by direct reaction of the corresponding elements at high temperature. It crystallizes in a noncentrosymmetric space group and represents a new structure type (tetragonal, P4nc with a=10.620(2) and c=9.009(2) A, Z=2). The structure is built of interconnected heteroatomic clusters of In(4)Bi(5), square pyramids with In(4)-bases and four exo-bonded bismuth atoms (bond to the In atoms). According to Wade's rule the compound is electron-deficient with one electron per cluster, that is, [In(4)Bi(5)](10-) instead of the expected [In(4)Bi(5)](11-) for a closed-shell species. The clusters are discussed also in light of the known heteroatomic deltahedral clusters with the same composition but different charge, [In(4)Bi(5)](3-). Band structure calculations on the new compound suggest substantial participation of barium in the overall bonding of the structure that "accounts" for the electron shortage

Rationally Functionalized Deltahedral Zintl Ions: Synthesis and Characterization of [Ge9-ER3]3-, [R3E-Ge9-ER3]2-, and [R3E-Ge9-Ge9-ER3]4- (E=Ge, Sn; R=Me, Ph)

Chemistry (Weinheim an Der Bergstrasse, Germany). Aug, 2004  |  Pubmed ID: 15281156

Six new derivatized deltahedral Zintl ions have been synthesized by reactions between the known Zintl ions Ge(9) (n-) with the halides R(3)EX and/or the corresponding anions R(3)E(-) for E=Ge or Sn. This rational approach is based on our previous discovery that these derivatization reactions are based on nucleophilic addition to the clusters. All species were structurally characterized as their salts with potassium countercations sequestered in 2,2,2-crypt or [18]crown-6 ether. The tin-containing anions were characterized also in solutions by (119)Sn NMR spectroscopy. The reaction types for such substitutions and the structures of the new anions are discussed.

Reversible Repositioning of Zinc Atoms Within Single Crystals of a Zinc Polycarboxylate with an Open-framework Structure

Journal of the American Chemical Society. Sep, 2004  |  Pubmed ID: 15327283

Upon dehydration at 220 degrees C under vacuum, an open-framework zinc tetrahydrofuran-2,3,4,5-tetracarboxylate undergoes reversible single crystal to single crystal conversion by some of the zinc atoms moving to different positions that are 3 A away. The reverse process occurs at room temperature by exposing dehydrated crystals to air.

Heavy-metal Aromatic Rings: Cyclopentadienyl Anion Analogues Sn5(6-) and Pb5(6-) in the Zintl Phases Na8BaPb6, Na8BaSn6, and Na8EuSn6

Inorganic Chemistry. Oct, 2004  |  Pubmed ID: 15446901

The title compounds were prepared by direct reactions of the corresponding elements at high temperature. They are isostructural with each other (monoclinic, P2(1)/m, Z = 2; Na(8)BaPb(6), a = 13.116(4), b = 5.351(1), and c = 16.166(5) A, beta = 108.07(2) degrees; Na(8)BaSn(6), a = 12.897(4), b = 5.362(1), and c = 16.826(5) A, beta = 108.19(2) degrees; Na(8)EuSn(6), a = 12.912(2), b = 5.220(1), and c = 15.721(2) A, beta = 108.09(1) degrees ) and contain isolated, flat, and aromatic pentagonal rings of Sn(5)(6)(-) and Pb(5)(6)(-) as well as isolated anions of Sn(4)(-) and Pb(4)(-). According to four-probe conductivity measurements, the tin compounds, Na(8)BaSn(6) and Na(8)EuSn(6), are semiconducting with band gaps of 0.11 and 0.09 eV, respectively, and are therefore electronically balanced. Magnetic measurements show that Na(8)BaSn(6) is diamagnetic while Na(8)EuSn(6) is paramagnetic and undergoes two transitions at low temperatures.

Ligand-free Deltahedral Clusters of Silicon in Solution: Synthesis, Structure, and Electrochemistry of Si9(2-)

Inorganic Chemistry. Apr, 2005  |  Pubmed ID: 15819550

Deltahedral nine-atom clusters of silicon, Si(9)(2-), were synthesized by mild oxidation of a liquid ammonia solution of K(12)Si(17) with Ph(3)GeCl in the presence of 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) or 2,2,2-crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane). The clusters were structurally characterized in [K(18-crown-6)](2)Si(9).C(5)H(5)N (yellow; orthorhombic, Pnma; a = 14.013(1), b = 18.108 (1), c = 18.320 (1) A; Z = 4) crystallized from a pyridine solution of the product of the aforementioned reaction in liquid ammonia. Si(9)(2-) is the first unequivocally characterized nine-atom cluster of group 14 with a charge of 2-. In addition to pyridine, the product from the reaction in liquid ammonia is also soluble in DMF, and the Si(9)(2-) clusters were characterized by mass spectrometry in such a solution. The more reduced clusters Si(9)(3-) have also been crystallized from pyridine solution. Cyclic voltammetry in both pyridine and DMF solutions clearly shows the Si(9)(2-)/Si(9)(3-) redox couple as one-electron reversible process. The structural similarities and differences between Si(9)(3-) and Si(9)(2-) are discussed herein.

[(Pd-Pd)@Ge18]4-: a Palladium Dimer Inside the Largest Single-cage Deltahedron

Journal of the American Chemical Society. Jun, 2005  |  Pubmed ID: 15913347

The largest single-cage deltahedral cluster is made of 18 germanium atoms and is centered by a pair of palladium atoms. Its shape is very close to the ideal D3d symmetry expected and predicted for a cluster of this size.

[(Ni-Ni-Ni)@(Ge9)2]4-: a Linear Triatomic Nickel Filament Enclosed in a Dimer of Nine-atom Germanium Clusters

Angewandte Chemie (International Ed. in English). Jun, 2005  |  Pubmed ID: 15929153

Heavy-metal Aromatic and Conjugated Species: Rings, Oligomers, and Chains of Tin in Li(9)(-)(x)EuSn(6+)(x), Li(9)(-)(x)CaSn(6+)(x), Li(5)Ca(7)Sn(11), Li(6)Eu(5)Sn(9), LiMgEu(2)Sn(3), and LiMgSr(2)Sn(3)

Inorganic Chemistry. Jul, 2005  |  Pubmed ID: 16022534

The title compounds were synthesized from the elements by heating the corresponding mixtures at high temperature. Their structures were determined from single-crystal X-ray diffraction. Li(9)(-)(x)()EuSn(6+)(x)(), Li(9)(-)(x)()CaSn(6+)(x)(), Li(5)Ca(7)Sn(11), and Li(6)Eu(5)Sn(9) contain columns of stacked aromatic pentagons of Sn(5)(6)(-) that are analogous to the cyclopentadienyl anion C(5)H(5)(-). The pentagons are separated with Ca(2+) or Eu(2+) in the columns and resemble a polymeric metallocene. In addition to the columns, the isostructural Li(9)(-)(x)()EuSn(6+)(x)() and Li(9)(-)(x)()CaSn(6+)(x)() contain isolated tin atoms and bent tin trimers while Li(5)Ca(7)Sn(11) and Li(6)Eu(5)Sn(9) contain flat zigzag hexamers and flat zigzag infinite chains of tin, respectively. The isostructural LiMgEu(2)Sn(3) and LiMgSr(2)Sn(3) do not contain columns of pentagons but only flat zigzag infinite chains of tin. The aromaticity of the pentagons and the conjugation of the pi-systems of the hexamers and the infinite chains are discussed. The title compounds are also characterized by magnetic and conductivity measurements.

Analysis of the Effect of Spin-orbit Coupling on the Electronic Structure and Excitation Spectrum of the Bi2(2-) Anion in (K-crypt)2Bi2 on the Basis of Relativistic Electronic Structure Calculations

The Journal of Physical Chemistry. A. Mar, 2005  |  Pubmed ID: 16833492

The Bi2(2-) anions that have been characterized in (K-crypt)2Bi2 are isoelectronic with O2 but are diamagnetic and EPR-silent, unlike O2. The UV-vis spectrum measured for (K-crypt)2Bi2 shows two broad absorption peaks located at 2.05 and 2.85 eV, but no absorption at lower energies down to 0.62 eV. To account for these observations, the electronic structures of the isoelectronic diatomic dianions Q2(2-) (Q = N, P, As, Sb, Bi) were compared on the basis of relativistic density functional theory calculations, and the electronic excitations of Bi2(2-) were analyzed on the basis of relativistic configuration interaction calculations. The extent of spin-orbit coupling, brought about by the relativistic effect, increases steadily in the order N < P < As < Sb < Bi such that the "closed-shell" state is more stable than the "open-shell" state for Bi2(2-), while the opposite is the case for N2(2-), P2(2-), As2(2-), and Sb2(2-). The nature of the electronic excitations of Bi2(2-) was assigned and discussed from the viewpoint of molecular orbitals in the absence of spin-orbit coupling.

Deltahedral Germanium Clusters: Insertion of Transition-metal Atoms and Addition of Organometallic Fragments

Journal of the American Chemical Society. Mar, 2006  |  Pubmed ID: 16551125

Reactions of nine-atom deltahedral clusters of germanium with Ni(COD)2 and/or Ni(PPh3)2(CO)2 in ethylenediamine yielded the Ni-centered heteroatomic 10-atom clusters [Ni@(Ge9Ni-CO)]2- and [Ni@(Ge9Ni-en)]3-, as well as the empty 10-atom heteroatomic cluster [Ge9Ni-CO]3-. A ligand exchange reaction between [Ni@(Ge9Ni-CO)]2- and potassium phenylacetylide produced the organically functionalized species [Ni@(Ge9Ni-CCPh)]3-. The empty cluster [Ge9Ni-CO]3- is a bicapped square antiprism where one of the capping vertexes is the nickel atom. The other three clusters are tricapped trigonal prisms where an additional 10th vertex of monoligated nickel caps a triangular base of the trigonal prism. As a result of this, that base opens up, and the distances within it become nonbonding. This ensures that all atoms of the cluster are equidistant from the central nickel atom, i.e., the cluster is very close to spherical. All species were structurally characterized in crystalline compounds with [K-(2,2,2-crypt)]+ countercations. They were also characterized in solution by mass spectrometry, IR, and 13C NMR.

In Search of Benzene-like Sn6(6-): Synthesis of Na4CaSn6 with Interconnected Cyclohexane-like Sn6(6-)

Inorganic Chemistry. May, 2006  |  Pubmed ID: 16711698

The title compound was synthesized in an attempt to produce stacked benzene-like Sn6(6-) rings separated by alkaline-earth cations in analogy with the recently reported stacks of aromatic cyclopentadienyl-like Sn5(6-) in Na8BaSn6 (in addition to isolated Sn4- anions). The resulting compound, synthesized from a stoichiometric mixture of the elements at high temperature, has the "correct" stoichiometry with six tin atoms and six positive charges. However, the rings of Sn6(6-) are puckered into chair-type cyclohexanes that are interconnected into isolated cylindrical tubes stuffed with Ca2+ between the rings. Such tubes, if fused to each other, form the hexagonal diamond structure. The new compound is electronically balanced according to magnetic and four-probe resistivity measurements. Reported are also the synthesis and properties of Na10EuSn12 and Na10YbSn12 which are isostructural with the known Na10CaSn12.

[Zn9Bi11]5-: a Ligand-free Intermetalloid Cluster

Angewandte Chemie (International Ed. in English). Aug, 2006  |  Pubmed ID: 16819751

Alkylation of Deltahedral Zintl Clusters: Synthesis of [R-Ge9-Ge9-R]4- (R = TBu, SBu, NBu, TAm and Structure of [tBu-Ge9-Ge9-tBu]4-

Inorganic Chemistry. Apr, 2007  |  Pubmed ID: 17311378

Reactions of nine-atom deltahedral clusters (Zintl ions) of germanium, Ge9n- (n = 2, 3, 4), with alkyl chlorides, RCl (R = tBu, nBu, sBu, tAm), yielded the corresponding dialkylated dimers of Ge9 clusters [R-Ge9-Ge9-R]4-. The tBu derivative with [K(2,2,2-crypt)]+ countercations was characterized in the solid state by single-crystal X-ray diffraction as [K(2,2,2-crypt)]4[tBu-Ge9-Ge9-tBu].7en (monoclinic, C2/c, a = 35.0914(10) A, b = 24.8161(6) A, and c = 16.8782(5) A, beta = 94.0136(17) degrees , V = 14662.0(7) A3, and Z = 4) and in solution by 1H and 13C NMR. All species were also characterized in solution by electrospray mass spectrometry in the negative-ion mode. These are the first main group deltahedral clusters functionalized with purely organic substituents.

In Search of Cyclohexane-like Sn6(12-): Synthesis of Li2Ln5Sn7 (Ln = Ce, Pr, Sm, Eu) with an Open-chain Heptane-like Sn7(16-) Instead

Inorganic Chemistry. May, 2007  |  Pubmed ID: 17428047

The title compounds were prepared by direct reactions of the corresponding elements at high temperature. They are isostructural and crystallize in the chiral orthorhombic space group P212121 (Li2Ce5Sn7: a = 6.273(1), b = 13.839(2), and c = 17.467(2) A; Li2Pr5Sn7: a = 6.241(1), b = 13.762(2), and c = 17.367(1) A; Li2Sm5Sn7: a = 6.262 (1), b = 13.809(1), and c = 17.432(1) A; Li2Eu5Sn7: a = 6.165(1), b = 13.562(2), and c = 17.128(1) A). The structure contains isolated Sn7 oligomers that resemble the carbon core of an open-chain heptane molecule C7H16. Although these heptamers are stacked along the a axis at a distance that is comparable to the distances within the heptamer, electronic structure calculations show that this intermolecular contact is nonbonding for a formal charge of 16- or higher per heptamer. A hypothetical lower charge of 14-, on the other hand, leads to positive and substantial bond-overlap population that would result in branched infinite chains of infinity[Sn714-]. Magnetic measurements of the Ce and Pr compounds indicate a 3+ oxidation state for the rare-earth cations and, therefore, 17 available electrons from the cations per formula unit. According to four-probe conductivity measurements, the compounds are metallic.

Hydrogen-bonded Metal-complex Sulfonate (MCS) Inclusion Compounds: Effect of the Guest Molecule on the Host Framework

Inorganic Chemistry. May, 2007  |  Pubmed ID: 17461580

Soft molecular host frameworks made of the hydrogen-bonded metal complex (MC) Co(NH3)(6)3+ and 4,4'-biphenyldisulfonate (BPDS) include different guest molecules to form inclusion compounds of the type (MC)2(BPDS)3.n(guest). Structurally characterized were six compounds with guest molecules of DMSO, DMF, piperidine, acetone, acetonitrile, and THF. The metal-complex sulfonate frameworks in all of them are of the pillared layer type where the layers are constructed of extensively hydrogen-bonded metal-complex cations and sulfonate (S) anions (and some hydrogen-bonded water) while the organic residues of the 4,4'-biphenyldisulfonate serve as pillars. The hydrogen-bonded MCS layers and the orientations of the pillars adjust and rearrange in order to generate cavities that would accommodate different guest molecules. The steric, electronic, and hydrogen-bonding needs of the guest molecules mold the soft framework into different structures. These MCS host-guest frameworks are very close structural analogues of the well-studied guanidinium sulfonate (GS) networks and mimic their flexibility and overall durability.

Heteroatomic Deltahedral Clusters: Synthesis and Structures of Closo-[Bi3Ni(4)(CO)6]3-, Closo-[Bi4Ni4(CO)6]2-, the Open Cluster [Bi3Ni6(CO)9]3-, and the Intermetalloid Closo-[Nix@[Bi6Ni6(CO)8)]4-

Journal of the American Chemical Society. Jun, 2007  |  Pubmed ID: 17550250

Reactions of ethylenediamine solutions of K4Bi5 with Ni(PPh3)2(CO)2 yielded four novel hetero-atomic Bi/Ni deltahedral clusters. Three of them, the 7-atom pentagonal bipyramidal [Bi3Ni4(CO)6]3-, the 8-atom dodecahedral [Bi4Ni4(CO)6]2-, and the Ni-centered or empty 12-atom icosahedral [Nix@[Bi6Ni6(CO)8]4-, are closo-species according to both electron count and shape. The centered icosahedral cluster resembles packing in intermetallic compounds and belongs to the emerging class of intermetalloid clusters. The shape of the fourth cluster, [Bi3Ni6(CO)9]3-, can be derived from the icosahedral Ni-centered [Ni@[Bi6Ni6(CO)8]4- by removal of three Bi- and one Ni-atoms of two neighboring triangular faces. The clusters were structurally characterized by single-crystal X-ray diffraction in compounds with potassium cations sequestered by 2,2,2-crypt or 18-crown-6 ether. They were also characterized in solution by electrospray mass spectrometry.

Addition of Alkenes to Deltahedral Zintl Clusters by Reaction with Alkynes: Synthesis and Structure of [Fc-CH=CH-Ge9-CH=CH-Fc]2-, an Organo-zintl-organometallic Anion

Angewandte Chemie (International Ed. in English). , 2007  |  Pubmed ID: 17661297

Organo-Zintl Clusters Soluble in Conventional Organic Solvents: Setting the Stage for Organo-Zintl Cluster Chemistry

Inorganic Chemistry. Dec, 2007  |  Pubmed ID: 18034475

Organo-Zintl cluster ions were synthesized by reactions of alkynes with Ge94- clusters in ethylenediamine. The triple bonds are hydrogenated to double bonds during the process. The resulting dial-kenylated species [RHC=CHGe9CH=CHR]2- have lower charge, their alkali-metal cations can be exchanged for tetralkylammonium cations, and the resulting compounds are soluble in nonpolar solvents. This was demonstrated with [H2C=CHGe9CH=CH2]2-, which was structurally characterized with [K-(18-crown-6)]+, [Me4N]+, and [Pr4N]+ as countercations. The solubility of its salt with [Oc4N]+ in various conventional organic solvents was studied.

Synthesis, Structures, and Magnetic Properties of Metal-coordination Polymers with Benzenepentacarboxylate Linkers

Inorganic Chemistry. Feb, 2008  |  Pubmed ID: 18095675

Three hybrid organic-inorganic coordination polymers with benzenepentacarboxylate (BPCA) linkers, [Co3(C6H(COO)5)(OH)(H2O)3] (1-Co), [Zn3(C6H(COO)5)(OH)(H2O)3] (2-Zn), and [Co5(C6H(COO)5)2(H2O)12].(H2O)12 (3-Co), were synthesized hydrothermally and were characterized structurally and magnetically. 1-Co and 2-Zn are isostructural [C2/c; Z=8; 1-Co, a=19.5350(6) A, b=10.4494(4) A, and c=13.2353(5) A, beta=97.2768(8) degrees; 2-Zn, a=19.5418(9) A, b=10.3220(10) A, and c=13.4660(10) A, beta=98.455(10) degrees] with three-dimensional structures that contain [M6] secondary building units bridged by BPCA ligands. A different cobalt-based compound, 3-Co, forms at lower pH and lower reaction temperature. Its structure [P21/c; Z=2; a=12.6162(2) A, b=11.3768(2) A, and c=15.3401(3) A, beta=91.539(1) degrees] is a more loosely packed framework with free (noncoordinated) carboxylic groups pointing at water-filled cavities in the framework. The magnetic phase diagram of 1-Co established through detailed magnetic measurements shows a metamagnetic transition below TN=3.8 K. The less-packed compound 3-Co, on the other hand, remains paramagnetic above 1.9 K. The three compounds are the first examples of coordination polymers with benzenepentacarboxylate linkers and fill the gap of coordination polymers involving benzenepolycarboxylate linkers of the general type C6H6-n(COOH)n, where n=2-6.

Tin-based Organo-Zintl Ions: Alkylation and Alkenylation of Sn9(4-)

Inorganic Chemistry. Jul, 2008  |  Pubmed ID: 18510308

Reactions of nine-atom deltahedral clusters (Zintl ions) of tin, Sn 9 (4-), with alkyl chlorides, RCl (R = (t) Bu, (n) Bu, (s) Bu), and alkynes (Me3Si-C[triple bond]C-SiMe3, Ph-C[triple bond]CH) yielded the corresponding alkylated and alkenylated clusters [Sn 9-R] (3-). The triple bonds of the alkynes are hydrogenated to double bonds in the process. These are the first tin-based organo-Zintl ions, that is Zintl ions of tin that were subsequently functionalized with organic groups. They are analogous to the recently reported germanium-based derivatives. The (t) Bu-, vinyl-, and styrene-functionalized clusters [Sn 9- (t) Bu] (3-), [Sn 9-CH=CH 2] (3-), and [Sn 9-CH=CH-Ph] (3-), respectively, were structurally characterized in the solid state with [K(2,2,2-crypt)] (+) countercations and in solution by electrospray mass spectrometry. Crystal data: [K(2,2,2-crypt)] 3[Sn 9- (t) Bu].2py, triclinic, P1, a = 14.4259(3), b = 16.2725(4), and c = 22.5593(5) A, alpha = 86.092(1), beta = 78.952(1), and gamma = 65.114(1) degrees , V = 4714.48(7) A (3), Z = 2; [K(2,2,2-crypt)] 3[Sn 9-CH=CH 2].2py, triclinic, P-1, a = 15.6988(3), b = 17.4195(4), and c = 17.4432(4) A, alpha = 86.299(1), beta = 81.566(1), and gamma = 85.349(1) degrees , V = 4696.27(18) A (3), Z = 2; [K(2,2,2-crypt)] 3[Sn 9-CH=CH-Ph].tol.0.75py, monoclinic, C2/c, a = 38.5883(9), b = 23.3893(5), and c = 25.0192(5) A, beta = 120.269(1) degrees , V = 19502.6(7) A (3), Z = 8.

Functionalization of Nine-atom Deltahedral Zintl Ions with Organic Substituents: Detailed Studies of the Reactions

Journal of the American Chemical Society. Jul, 2009  |  Pubmed ID: 19496567

Presented are the results of a systematic investigation of the reactions of nine-atom deltahedral clusters of germanium (Zintl ions, Ge(9)(n-)) with alkynes and alkyl halides that result in alkenylation and alkylation of the clusters, respectively. The reaction pathways have been probed in depth using various, appropriately substituted alkynes and organic halides, including some typical mechanistic probes and radical clocks. The regioselectivity and stereoselectivity of the reaction with alkynes was examined by systematically varying the steric and electronic nature of the substituents. The studies showed that the Zintl clusters act as strong, anionic nucleophiles toward the alkynes and primary and secondary alkyl halides but, most likely, as electron donors in reactions with tertiary alkyl halides and halogenated olefins. The pentenyl and methylcyclopropyl functionalized clusters, [Ge(9)(C(5)H(9))](3-) and [Ge(9)(CH(2)CH(CH(2))(2))](2-), respectively, were crystallographically characterized in compounds with [K-crypt](+) countercations. All compounds were also analyzed by NMR and electrospray mass spectrometry.

Metal-organic Frameworks with Direct Transition Metal-sulfonate Interactions and Charge-assisted Hydrogen Bonds

Inorganic Chemistry. Jul, 2009  |  Pubmed ID: 19537705

Seven compounds with framework structures made of divalent metal-imidazole (Im) complexes (M(II) = Co, Ni, and Mn) linked by 1,5-napthalenedisulfonate (1,5nds) were synthesized and structurally characterized. Five of these compounds, Mn(Im)(4)(1,5nds) (two forms), Co(Im)(4)(1,5nds) (two forms), and Ni(Im)(4)(1,5nds), contain direct sulfonate-metal coordination and represent the first such compounds with open d-shell transition metals without Jahn-Teller distortion. The two disulfonate ligands in these octahedrally coordinated metal centers are found in both trans- and cis-geometries and link the centers into chains. The chains are held together by charge-assisted hydrogen bonds between sulfonate and imidazole ligands from different chains. The remaining two compounds, Co(Im)(6)(1,5nds) x 2 H(2)O and Ni(Im)(6)(1,5nds) x 2 H(2)O, exhibit only charge-assisted hydrogen bonds between the octahedral M(Im)(6)(2+) cations and the disulfonate anions.

Isolated Co15 Clusters and Their Assembly into a 3D Network: Conformation-directed Synthesis

Inorganic Chemistry. Sep, 2009  |  Pubmed ID: 19658400

Isolated clusters of 15 Co atoms interconnected by six organic linkers, each with two carboxylic and one phosphonic groups, N(CH(2)COO(-))(2)(CH(2)PO(3)(2-)), are synthesized with deprotonated trans-cyclohexanehexacarboxylic acid, C(6)H(6)(COO(-))(6), as counteranions. The cis conformation of the latter, on the other hand, coordinates to the same clusters by replacing the terminal water ligands and links them into a 3D network.

Heteroatomic Deltahedral Zintl Ions of Group 14 and Their Alkenylation

Inorganic Chemistry. Jan, 2010  |  Pubmed ID: 20000832

Reported is the synthesis of Ge(9-x)Sn(x) heteroatomic deltahedral Zintl ions and their alkenylation by reactions with alkynes. The nine-atom clusters are made either by extraction from mixed Ge/Sn precursors with nominal composition K(4)Ge(9-x)Sn(x) or by dissolution of mixtures of the corresponding binary precursors K(4)Ge(9) and K(4)Sn(9) in solvents with high dielectric constants such as DMF, DMSO, and acetonitrile. Reactions of the heteroatomic clusters with alkynes such as Me(3)SiC[triple bond]CSiMe(3), HC[triple bond]CCpr (Cpr = cyclopropyl), and HC[triple bond]CPh in ethylenediamine resulted in the following structurally characterized compounds with alkenylated heteroatomic clusters: [K-(2,2,2-crypt)](3)[GeSn(8)-CH=CH(2)].en.tol (1), triclinic, P1, a = 13.9220(3) A, b = 14.9788(3) A, and c = 21.5892(5) A, alpha = 94.2580(10) degrees , beta = 98.5210(10) degrees , and gamma = 98.4890(10) degrees , V = 4382.31(16) A(3), Z = 2; [K-(2,2,2-crypt)](4)[Ge(2)Sn(7)(CH=CH(2))(2)](2).en (2), monoclinic, P2(1)/c, a = 48.1883(15) A, b = 12.1551(4) A, and c = 21.4824(7) A, beta = 90.052(2) degrees , V = 12583.0(7) A(3), Z = 4; [K-(2,2,2-crypt)](3)[GeSn(8)-CH=CHCpr].en (3), monoclinic, P2(1)/c, a = 17.9132(9) A, b = 22.7967(11) A, and c = 21.6922(12) A, beta = 98.409(2) degrees , V = 8763.0(8) A(3), Z = 4; [K-(2,2,2-crypt)](3)[Ge(2)Sn(7)-CH=CHPh].2en (4), monoclinic, P2(1)/n, a = 13.2583(5) A, b = 47.0565(17) A, and c = 15.9978(6) A, beta = 111.536(2) degrees , V = 9284.1(6) A(3), Z = 4. The potassium countercations of the divinyl-substituted cluster in 2 were exchanged for tetrapropylammonium cations, and the resulting compound was also crystallized and structurally characterized: [Pr(4)N](4)[Ge(2)Sn(7)(CH=CH(2))(2)](2) (5), triclinic, P1, a = 11.6757(8) A, b = 18.8150(16) A, and c = 21.0608(17) A, alpha = 112.327(3) degrees , beta = 91.550(3) degrees , and gamma = 91.892(3) degrees , V = 4273.5(6) A(3), Z = 2. All clusters were also characterized in solution by electrospray mass spectrometry.

The Elusive Closo-Ge(10)(2-) Zintl Ion: Finally "captured" As a Ligand in the Complex [Ge(10)Mn(CO)(4)](3-)

Inorganic Chemistry. Jul, 2010  |  Pubmed ID: 20552962

Although often seen in mass spectra, the otherwise elusive closo-Ge(10)(2-) Zintl ion has been finally structurally characterized as coordinated to manganese in [Ge(10)Mn(CO)(4)](3-) made by the reaction of nido-Ge(9)(4-) with Mn(2)(CO)(10) in ethylenediamine. The new cluster is a bicapped square antiprism, as expected for a closo-deltahedron of 10 atoms.

Addition of a Thallium Vertex to Empty and Centered Nine-atom Deltahedral Zintl Ions of Germanium and Tin

Inorganic Chemistry. Mar, 2011  |  Pubmed ID: 21294520

Nickel atoms were inserted into nine-atom deltahedral Zintl ions of E(9)(4-) (E = Ge, Sn) via reactions with Ni(cod)(2) (cod = cyclooctadiene), and [Ni@Sn(9)](3-) was structurally characterized. Both the empty and the Ni-centered clusters react with TlCp (Cp = cyclopentadienyl anion) and add a thallium vertex to form the deltahedral ten-atom closo-species [E(9)Tl](3-) and [Ni@E(9)Tl](3-), respectively. The structures of [Ge(9)Tl](3-) and [Ni@Sn(9)Tl](3-) showed that, as expected, the geometry of the ten-atom clusters is that of a bicapped square antiprism where the Tl-atom occupies one of the two capping vertices. This illustrates that centering a nine-atom cluster with a nickel atom does not change its reactivity toward TlCp. All compounds were characterized by electrospray mass spectrometry.

"n-Doping" of Deltahedral Zintl Ions

Journal of the American Chemical Society. May, 2011  |  Pubmed ID: 21476584

We report a simple and efficient method for replacing germanium atoms in deltahedral Ge(9)(4-) clusters with Sb or Bi. While reactions of Ge(9)(4-) with EPh(3) (E = Sb, Bi) at room temperature are known to produce mono- and disubstituted clusters [Ph(2)E-Ge(9)-Ge(9)-EPh(2)](4-) and [Ph(2)E-Ge(9)-EPh(2)](2-), respectively, at elevated temperatures or with sonication they result in exchange of Ge cluster atoms with Sb or Bi. Structurally characterized from such reactions are the novel "n-doped" deltahedral Zintl ions [(EGe(8))-(Ge(8)E)](4-), (Sb(2)Ge(7))(2-), and [(SbGe(8))-SbPh(2)](2-).

Metal-centered Deltahedral Zintl Ions: Synthesis of [Ni@Sn9]4- by Direct Extraction from Intermetallic Precursors and of the Vertex-fused Dimer [{Ni@Sn8(μ-Ge)(1/2)}2]4-

Inorganic Chemistry. Nov, 2011  |  Pubmed ID: 22026406

Ni-centered deltahedral Sn(9) clusters with a charge of 4-, i.e., [Ni@Sn(9)](4-), were extracted in ethylenediamine in high yield directly from intermetallic precursors with the nominal composition "K(4)Sn(9)Ni(3)". The new endohedral clusters were crystallized and structurally characterized in K[K(18-crown-6)](3)[Ni@Sn(9)]·3benzene (1a, triclinic, P1̅, a = 10.2754(5) Å, b = 19.5442(9) Å, and c = 20.5576(13) Å, α = 73.927(3)°, β = 79.838(4)°, and γ = 84.389(3)°, V = 3899.6(4) Å(3), Z = 2) and K[K(2,2,2-crypt)](3)[Ni@Sn(9)] (1b, triclinic, P1, a = 15.8028(8) Å, b = 16.21350(9) Å, and c = 20.1760(12) Å, α = 98.71040(10)°, β = 104.4690(10)°, and γ = 118.3890(10)°, V = 4181.5(4) Å(3), Z = 2). The alternative method of a post-synthetic insertion of a Ni atom in empty Sn(9) clusters by a reaction with Ni(cod)(2) predominantly produces the more-oxidized clusters with a charge of 3-, i.e., the recently reported [Ni@Sn(9)](3-). Nonetheless, using substoichiometric amounts of 18-crown-6 as a cation sequestering agent, we also have been able to isolate the 4- clusters as a minor phase from such reactions. They were structurally characterized in K[K(en)][K(18-crown-6)](2)[Ni@Sn(9)]·0.5en (2, monoclinic, P2(1)/n, a = 10.4153(5) Å, b = 25.6788(11) Å, and c = 20.6630(9) Å, β = 102.530(2)°, V = 5394.7(4) Å(3), Z = 2). The ability of the Ni-centered clusters to exist with both 3- and 4- charges parallels the same ability of the empty clusters and is very promising for similarly rich chemistry involving electron transfer and flexible "oxidation states". We also report the synthesis and characterization of the endohedral heteroatomic dimer [{Ni@Sn(8)(μ-Ge)(1/2)}(2)](4-) composed of two [Ni@(Sn(8)Ge)]-clusters fused at the Ge-vertex. The dimer was synthesized by reacting an ethylenediamine solution of a ternary precursor with the nominal composition "K(4)Ge(4.5)Sn(4.5)", which is known to produce heteroatomic Ge(9-x)Sn(x) clusters, with Ni(cod)(2). It is isostructural with the reported [{Ni@Sn(8)(μ-Sn)(1/2)}(2)](4-) and is structurally characterized in [K-(2,2,2-crypt)](4)[{Ni@Sn(8)(μ-Ge)(1/2)}(2)]·2en (3, monoclinic, C2/c, a = 30.636(2) Å, b = 16.5548(12) Å, and c = 28.872(2) Å, β = 121.2140(10)°, V = 12523.5(15) Å(3), Z = 4).

Hydrogen-bonded Inclusion Compounds with Reversed Polarity: Anionic Metal-complexes and Cationic Organic Linkers

Inorganic Chemistry. Dec, 2011  |  Pubmed ID: 22085246

Synthesized and structurally characterized is a new series of soft-host frameworks assembled by charge-assisted hydrogen bonds between an anionic metal complex (MC) and cationic organic linkers (OL), specifically [Co(en)(ox)(2)](-) and diprotonated 4,4'-bipyridinium (H(2)bpy) or 1,2-bis(4-pyridinium)ethylene (H(2)bpye). While frameworks built of cationic complexes and anionic organic linkers are already well-known, the seven new compounds described here represent the first series of frameworks with reversed polarity, that is, made of anionic complexes and cationic organic linkers. The compounds have a general formula [OL][MC](2)·n(guest), where the guest molecules 4,4'-biphenol (bp), 4-methoxyphenol (mp), 1,4-dimethoxybenzene (dmb), 1,6-dimethoxynaphtalene (dmn), and 4-nitroanisole (na). Structurally the compounds can be described as pillared-layer frameworks with layers constructed of MC anions and linked together by hydrogen-bonded cationic OL pillars. The guest molecules occupy the galleries between the pillars while their steric, electronic, and π-π and hydrogen-bonding capabilities influence the overall structure of the soft frameworks.

Rational Synthesis of [Ge(9){Si(SiMe(3))(3)}(3)](-) from Its Parent Zintl Ion Ge(9)(4-)

Inorganic Chemistry. Jan, 2012  |  Pubmed ID: 22288571

Reported is the first rational synthesis of a trisubstituted deltahedral Zintl ion, [Ge(9){Si(SiMe(3))(3)}(3)](-) in this case, by the addition of the three substituents in a reaction of the parent naked deltahedral Zintl ion Ge(9)(4-) with {(Me(3)Si)(3)Si}Cl. The new species were crystallized and structurally characterized in [K(2,2,2-crypt)](2)[Ge(9){Si(SiMe(3))(3)}(3)] (monoclinic, P2(1)/c, a = 26.497(3) Å, b = 24.090(2) Å, c = 29.268(3) Å, β = 113.888(2)°, V = 17082(3) Å(3), Z = 8, R1/wR2 = 0.0436/0.0812 for the observed data and 0.1023/0.1010 for all data).