Efficient Carbene and Carbyne Formation in Molybdenum(0) and Tungsten(0) Dinitrogen Complexes

Abstract

Zerovalent group 6 dinitrogen phosphine complexes react with 3,3-diphenylcyclopropene to give vinylcarbyne hydride complexes that have been characterized crystallographically. Computational studies indicate that the observed products resulted from the α-migration and rearrangement of an initially formed vinylcarbene.

Structural and conformational study of pentacarbonyl and phosphine substituted Fischer alkoxy- and aminocarbene complexes of molybdenum

“…Triethyloxonium tetrafluoroborate [19] was prepared according to a reported literature procedure. The reagents [Mo(CO) 6 ], n-butyl lithium (1.6 M solution in hexane), furan, 1,2-bis(diphenylphosphino)ethane (dppe), PPh 3 , cyclohexyl amine (NH 2 Cy) and other commercial reagents were used as purchased. NMR spectra were recorded on a Bruker ARX-300.…”

“…Furan was monolithiated at À30°C with n-BuLi in THF as solvent. Subsequent reaction with Mo(CO) 6 , followed by alkylation in dichloromethane, yields the desired pentacarbonyl carbene complex. Aminolysis of 1 with either cyclohexyl amine or ammonia in diethyl ether, led to the formation of 4 and 7, respectively.…”

“…Although the synthesis [3][4][5][6] and structure [7,8] of selected Mo(0) Fischer carbene complexes have been described in literature, there are no systematic studies reported on the different conformations of Mo(0) Fischer carbene complexes.…”

Effect of CO substitution on the redox properties of Fischer Mo(0) carbene complexes Mo(CO)5=C(Y)(2-Furyl), Y=OEt, NHCy or NH2

“…These complexes contained a chiral biphosphite ligand and it was shown that the fac isomer could be converted to the mer isomer under thermal conditions. Ning et al [8] found that by using group VI metal compounds, specifically chromium and molybdenum compounds containing dinitrogen and phosphine ligands, the synthesis of a vinylcarbyne hydride complex, via a vinylcarbene intermediate, could be achieved. The synthesis and structure of a series of molybdenum-Fischer carbene complexes [4,9] and bimetallic carbene complexes of molybdenum with multiple thiophene rings as bridging units have been reported by Landman et al [10].…”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…1521, Scheme 124) were prepared from the reaction of the dinitrogen complex 1518 with 3,3-diphenylcyclopropene (1519) [1312]. A mechanism that involves M a n u s c r i p t 183 formation of an agostically-bound carbene complex (1520) followed by α-hydride elimination was proposed and supported through DFT studies.…”