Biomaterial Database

A comparison between nickel and palladium precatalysts of 1,2,4-triazole based N-heterocyclic carbenes in hydroamination of activated olefins. 2010

Chandrakanta Dash, and Mobin M Shaikh, and Ray J Butcher, and Prasenjit Ghosh

Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.

A comparison is drawn between the nickel and palladium precatalysts of 1,2,4-triazole based N-heterocyclic carbenes in the hydroamination of activated olefins. Though all of the newly designed nickel and palladium precatalysts, trans-[1-i-propyl-4-R-1,2,4-triazol-5-ylidene](2)MBr(2) [R = Et, M = Ni (1b); R = Et, M = Pd (1c); R = CH(2)CH=CH(2), M = Ni (2b) and R = CH(2)CH=CH(2), M = Pd (2c)], are moderately active for hydroamination reaction of a variety of secondary amines viz. morpholine, piperidine, pyrrolidine and diethylamine with activated olefins like, acrylonitrile, methyl acrylate, ethyl acrylate and t-butyl acrylate at room temperature in 1 hour, the nickel complexes (1b and 2b) exhibited superior activity compared to its palladium counterparts (1c and 2c). The better performance of the nickel complexes has been correlated to the more electron deficient metal center in the nickel 1b and 2b complexes than in the palladium 1c and 2c analogs based on the density functional theory studies. The 1b-c and 2b-c complexes were synthesized by the reaction of 1-i-propyl-4-R-1,2,4-triazolium bromide [R = Et (1a) and R = CH(2)CH=CH(2) (2a)] with MCl(2) [M = Ni, Pd] in presence of NEt(3) as a base.

UI	MeSH Term	Description	Entries
D008697	Methane	The simplest saturated hydrocarbon. It is a colorless, flammable gas, slightly soluble in water. It is one of the chief constituents of natural gas and is formed in the decomposition of organic matter. (Grant & Hackh's Chemical Dictionary, 5th ed)
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D009532	Nickel	A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.
D010165	Palladium	A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
D006571	Heterocyclic Compounds	Cyclic compounds that include atoms other than carbon in their ring structure.	Heterocyclic Compound,Compound, Heterocyclic,Compounds, Heterocyclic
D006865	Hydrogenation	Addition of hydrogen to a compound, especially to an unsaturated fat or fatty acid. (From Stedman, 26th ed)	Hydrogenations
D000475	Alkenes	Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)	Alkene,Olefin,Olefins,Pentene,Pentenes
D000586	Amination	The creation of an amine. It can be produced by the addition of an amino group to an organic compound or reduction of a nitro group.	Aminations
D014230	Triazoles	Heterocyclic compounds containing a five-membered ring with two carbon atoms and three nitrogen atoms with the molecular formula C2H3N3.	Triazole