The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphos^Ph Complexes

The overall goal of this procedure is to prepare Ruthenium Dihydrate complexes that also incorporate a facially capping and TFOs ligand. This is accomplished by first synthesizing the trip and TFOs ligand. The second step is to coordinate the end TFOs ligand to ruthenium zero as a bicarbonate complex.

Next, the Ruthenium center is oxidized using molecular oxygen as the oxygen in tandem, converting a single carbonyl ligand to a carbonate. The final step is hydrogenation of the resultant carbonate complex, forming a dihydrate complex and releasing carbon dioxide and water. Ultimately, phosphorus and proton NMR spectroscopy are used to show formation of the desired complex with a characteristic presence of high field resonances In the proton NMR spectrum indicative of hydride ligands, We first had the idea for this method when we were looking for a straightforward and simple way of preparing ruthenium to IDE complexes from ruthenium zero compounds.

Visual demonstration of this experiment is critical as the oxidation step is hard, over oxidation may lead to decomposition. First, add 6.99 grams of diphenyl hydroxy methylene phospho chloride to a 200 milliliter oven dried flank flask and place under nitrogen via three sequential vacuum nitrogen cycles on a dual manifold flank line. Following this, add 30 milliliters of Degas methanol and 9.5 milliliters of triethylamine to the flask.

Stir the solution at room temperature for one hour to ensure conversion of the phospho chloride salt to the hydroxy methane phosphine. After one hour, add 4.1 milliliters of two molar DGAs ammonia solution in methanol to the flask. Heat the reaction mixture for two hours under reflux during which the ligand will precipitate out as a white solid, although the phos ligand is stable to oxidation in air over short periods of time for optimal purity, remove the solvent via cannula filtration under nitrogen.

Rinse three times with 10 milliliters of Degas methanol to obtain an analytically pure product. Then store the product under a nitrogen atmosphere. Next, add one gram of ntri phos and 347 milligrams of tri ruthenium doca.

Carbinol to a 200 milliliter oven dried flank flask. After placing under nitrogen via three sequential vacuum nitrogen cycles, add 30 milliliters of dry DGAs toluene and bring the mixture to reflux for 12 hours. After allowing the solution to cool to room temperature, filter the solution via cannula to a second SL flask to remove small amounts of metallic ruthenium that form during the course of the reaction.

Then reduce the volume of solvent to approximately 10 milliliters under vacuum using a dual manifold shank line fitted with a liquid nitrogen cooled trap to induce precipitation of the complex rech. Crystallize the precipitate by heating gently to 80 to 90 degrees Celsius in an oil bath until complete resolution occurs. Turn off the heat to allow the solution to slowly cool to room temperature while keeping the sch flank flask submerged in the oil bath.

Leave overnight to give an orange crystal and solid following this. Isolate the orange crystal suitable for x-ray diffraction via cannula filtration of the supernatant into another oven dried flank flask. Rinse the crystals two times with five milliliters of dry degas toluene.

After drying in Vao overnight store the complex under nitrogen as exposure to air leads to slow conversion of the oxidized carbonate complex. At this point, at 280 milligrams of ruthenium bicarbonate and TFOs, and five milliliters of toluene to a 200 milliliter shank flask. To generate a partially dissolved orange suspension, insert a needle attached to a balloon of oxygen into the suspension and bubble oxygen at a rate of two to three bubbles per second through the reaction mixture for 10 minutes.

As an orange precipitate forms collected by filtration in air and washed two times with five milliliters of toluene and five milliliters of dathyl ether dry and vao to give a free flowing orange powder that is stable in air in order to grow crystals suitable for X-ray diffraction dissolve 100 milligrams of the orange solid in three milliliters of di chloro methane in a vial, and layer three milliliters of toluene on top by slowly allowing the solvent to run down the side of the vial. After allowing the solution to sit overnight, isolate the crystals that have precipitated out of solution by decanting the supernatant. Then wash the crystals two times with three milliliters of toluene and two milliliters of dathyl ether dry and vao on a dual manifold shank.

Line next dissolve 763 milligrams of ruthenium carbonate carbonyl and tri phos in 20 milliliters of dry DGAs tetra hydro furan and inject the solution into a 100 milliliter autoclave engineer's high pressure reactor Under a positive pressure of nitrogen, change the reactor headspace gas to 100%hydrogen and pressurized to 15 bar at room temperature. Then heat to 100 degrees Celsius with stirring for two hours after cooling to room temperature, carefully vent the excess hydrogen gas in the reactor head space and change to nitrogen following this. Transfer the reaction solution to a 100 milliliter shank flask under nitrogen.

After reconnecting to a dual manifold flank line and filtering via cannula, dilute the solution with 20 milliliters of dry degas methanol. Remove the solvent under vacuum using a dual manifold sch flank line fitted with a liquid nitrogen cooled trap to give an orange powder. Wash this orange powder three times with five milliliters of dry degas methanol and five milliliters of dry degas ethyl ether at this point dissolve 48.4 milligrams of ruthenium, dihydrate carbonyl and tri phos in two milliliters of dry degas toluene in an oven dried flank flask.

Add this solution via syringe to a stirring solution of 10.6 milligrams of ammonium hof fluoro phosphate in two milliliters of acetone nitrile in a separate oven dried flank flask. After stirring the reaction mixture at room temperature for two hours, remove the solvent in vao using a dual manifold shank line fitted with a liquid nitrogen cooled trap to give the intermediate complex ruthenium hydride carbonyl, acetone, nitrile and phos. Wash the complex three times with three milliliters of dry DGAs hexane, then dry and vao to isolate the complex as a brown powder to a solution of the complex.

In 0.5 milliliters of DGAs derated acetone, add 10.8 milligrams of leic acid in 0.5 milliliters of DGAs derated acetone. Stir the reaction mixture for two minutes using a vortex stir. Finally, record proton and phosphorus NMR spectra of the reaction every hour for 16 hours to monitor the reaction reaction of Tric Phos one with Tri Ruthenium do Decarol results in the bicarbonate complex.

Two, that shows a higher frequency shift of a singlet in the phosphorus NMR spectrum, indicating that all the phosphine arms are coordinated to ruthenium and in the same chemical environment. The x-ray crystal structure confirmed this observation. A significant change in the phosphorus NMR spectrum is observed for ruthenium complex three.

A triplet and doublet are seen as there are two different phosphorus environments, a result of loss of symmetry upon carbonate formation. X-ray diffraction analysis confirmed this structure. The phosphorus NMR spectrum of hydrogenation product four gave a doublet and triplet indicating two different phosphorus environments.

The proton NMR spectrum shows hydride resonances in the low frequency region as a multiplet. X-ray diffraction analysis confirmed the dihydrate complex structure. The phosphorus NMR spectrum of complex five shows a multiple and two doublet of doublets as there are three different phosphorus environments owing to the three different trans ligands coordinating to ruthenium in the low frequency region of the proton NMR spectrum.

A pseudo doublet of triplets is observed. The proton NMR spectrum of Complex six after 21 hours shows the complete disappearance of the ruthenium hydrogen signal and the phosphorus NMR spectrum shows a pseudo triplet and doublet. After watching this video, you should have a really good understanding of how to synthesize ruthenium and trifus complexes that also feature the trius ligand in a facially caffeine coordination.

Don't forget that working with high pressure systems can be extremely hazardous and ensure that all appropriate safety precautions are taken in while doing this procedure.