Theoretical studies of [MYR2]n isomers (M = B, Al, Ga; Y = N, P, As; R = H, CH3): structures and energetics of monomeric and dimeric compounds (n = 1, 2)

A series of group 13-15 compounds of the general formula [MYR(2)](n) (M = B, Al, Ga; Y = N, P, As; n = 1, 2; R = H, CH(3)) have been theoretically studied at the B3LYP/TZVP level of theory. The stability of different isomer structures is discussed to reveal the competitiveness of group 13-13, group 13-15, and group 15-15 bonding. Preferential bonding patterns and trends in the stability with respect to M and Y are also discussed. For the dimeric compounds, C(2v) symmetric [HMYH](2) rings are the lowest in energy, with the single exception of Ga(2)N(2)H(4), for which a somewhat unexpectedly C(2v) symmetric [GaNH(2)](2) ring is found to be the energy minimum, followed by the planar H(2)NGaGaNH(2) chain. The higher stability of the GaNH(2) bonding pattern in oligomer compounds may be rationalized in terms of the increasing stability of the oxidation state I as compared to that for the boron and aluminum analogues. Methylation significantly reduces the energetic differences between monomeric MYMe(2) MeMYMe, and Me(2)MY, isomers, especially for the AlP, AlAs, and GaAs systems, thus allowing a variety of structural types to be competitive in energy.     

Aurolysis of alpha-C-deprotonated group 6 aminocarbene and thiocarbene complexes with Ph3PAu+

Deprotonated Fischer-type aminocarbene complexes, (CO)5M=C(NR2)CH3 (M = Cr or W; R = Me or propyl), react with Ph3PAu+ by metal group substitution - (CO)5M for Ph3PAu+--and attachment of the extricated M(CO)5 to the deprotonated methyl group. (The products may also be seen as aminovinylgold compounds coordinated to M(CO)5 moieties.) DFT calculations at the B3LYP level of theory using model compounds indicate a clear preference of the gold unit for central C to terminal coordination in the ligand [NMe2CCH2]-, whereas the Cr(CO)5 has a 7 kcal mol(-1) preference for C(vinyl) coordination compared to N-coordination. In related thiocarbenes, the sulfur donor atom should be the preferred point of attachment for the metal carbonyl unit. The latter prediction is borne out in practice, and in the three products isolated, including Ph3PAu{C(=CH2)SPh}Cr(CO)5 in a mixed crystal with [Ph3PAuSPh]Cr(CO)5, precisely this coordination mode is present. The latter component of the mixed crystal has also been prepared independently of the vinyl one.     

ChemInform Abstract: Ring,Chain, and Cluster Compounds in the Cl—Ga—N—H System.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: DFT Modeling of Chemical Vapor Deposition of GaN from Organogallium Precursors. Part 1. Thermodynamics of Elimination Reactions.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: DFT Modeling of Chemical Vapor Deposition of GaN from Organogallium Precursors. Part 2. Structures of the Oligomers and Thermodynamics of the Association Processes.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.