Bromide Leaving Group
Bromide Leaving Group - Related Videos
02:14
Leaving Groups
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2023
The nature of leaving groups strongly influences the outcome of a nucleophilic substitution reaction. In general, in a nucleophilic substitution reaction, a nucleophile displaces a functional group, called the leaving group, from the substrate to give a substituted product. A leaving group departs the substrate molecule through heterolytic cleavage, taking the pair of electrons with it to become a relatively stable weak base in the form of an anion or a neutral molecule. In a nucleophilic...
08:46
Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of Phosphorus(I)
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Cited by 4 •
2016
The synthesis of a triphosphenium bromide salt is described and its use as a P+ transfer agent is outlined by reactions with an N-heterocyclic carbene and an anionic bisphosphine, yielding an NHC-stabilized P(I) cation and a P(I) containing zwitterion, respectively.
07:08
Detection of Histone Modifications in Plant Leaves
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Cited by 22 •
2011
A reliable and useful approach to detect histone modifications on specific plant genes is described. The approach combines chromatin immunoprecipitation (ChIP) and real-time quantitative PCR. It allows detection of histone modifications on specific genes with a role in diverse physiological processes.
04:18
DNA Electrophoresis Using Thiazole Orange Instead of Ethidium Bromide or Alternative Dyes
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Cited by 5 •
2019
Here, we present a protocol to use thiazole orange for the detection of DNA in gel electrophoresis experiments. The use of thiazole orange allows elimination of ethidium bromide, and fluorescence detection can be achieved with either UV or blue light.
03:03
Inoculating a Bacterial Pathogen into Arabidopsis Leaves via Vacuum Infiltration
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2026
Source: Rufián, J. S., et.al. Single-Cell Analysis of the Expression of Pseudomonas syringae Genes within the Plant Tissue. J. Vis. Exp. (2022)This video demonstrates a vacuum infiltration method to introduce a bacterial pathogen into Arabidopsis plant leaves. The approach uses a prepared bacterial suspension and vacuum pulses to enable uniform entry through stomata, resulting in controlled leaf infection.
FAQs
Its effectiveness reflects the combined properties of Br−. The ion is stable and weakly basic, so it can depart without strongly resisting separation from carbon. Bromide is also polarizable, meaning its electron distribution can adjust as the carbon-bromine bond breaks. Together, these features support bromide departure in both substitution and elimination pathways.
During SN2 substitution, an incoming nucleophile displaces bromide in one concerted step. Formation of the new bond to the nucleophile occurs while the carbon-bromine bond breaks, and the bonding electron pair remains with bromine. Because these events occur together, the leaving group is directly involved in the single transition from reactants to substituted product.
In an SN1 reaction, the substrate first undergoes ionization, meaning the carbon-bromine bond breaks before the nucleophile completes the substitution process. Bromide departs with the bonding electron pair, producing the ionized reaction intermediate described by this pathway. This stepwise sequence differs from SN2 substitution, where departure and nucleophile attack occur together.
In elimination, a base removes a proton from a carbon neighboring the one bonded to bromine while bromide leaves. These linked events produce a new unsaturation in the organic product rather than replacing bromine with a nucleophile. Thus, the same leaving-group behavior can support a different reaction outcome when a neighboring proton and base participate.
The selected pathway influences both reaction rate and stereochemical outcome. A concerted SN2 process, stepwise SN1 ionization, and base-assisted elimination organize bond breaking and bond formation differently. Examining how bromide departs, whether a nucleophile or base is involved, and whether a neighboring proton is available helps connect the mechanism to the product formed.
Bromide-containing substrates provide a reaction site where a nucleophile can replace bromide or a base can promote elimination. Their behavior therefore helps chemists plan transformations and anticipate whether substitution or elimination is more relevant. Tracking bromide departure also supports predictions about reaction rates, stereochemical consequences, and the identity of the organic product.