164588-99-2Relevant academic research and scientific papers
Reactions of low-valent group V dicarbonyl phosphine complexes with carbon-based electrophiles to produce metal alkyl, acyl, carbyne, and acetylene complexes
Bronk, Brian S.,Protasiewicz, John D.,Pence, Laura E.,Lippard, Stephen J.
, p. 2177 - 2187 (1995)
The [V(CO)2(dmpe)2]- anion reacts with Et3OBF4 and EtOTf to afford the unexpected product of formal C-alkylation, [V(η2-C(O)Et)(CO)(dmpe)2], which has been structurally characterized by X-ray crystallography (space group Pna21, a = 12.917(2) A?, b = 12.335(2) A?, c = 14.331(2) A?, V = 2283.4(5) A?3). The formation of species derived by O-acylation of the CO ligands in the [Ta(CO)2(dmpe)2]- and [Ta(CO)2(depe)2]- anions was indirectly established by isolation and characterization of products in which two CO ligands had coupled to form acetylene complexes. Addition of 2 equiv of acetyl chloride to Na[Ta(CO)2(dmpe)2] or Na[Ta(CO)2(depe)2] yielded the acetylene complexes [Ta(AcOC≡COAc)(dmpe or depe)2Cl]. The structure of the dmpe derivative was confirmed in a single-crystal X-ray determination (space group C2, a = 14.964(2) A?, b = 11.960(2) A?, c = 31.710(5) A?, β = 102.77(1)°, V = 5535(1) A?3). Additional proof of direct alkylation at terminal CO ligands was provided by isolation of mixed siloxy/alkoxyacetylene coupled products [M(R′3SiOC≡COR)(dmpe)2X] (R = Et, Ac, CO2Me; R′3Si = tBuPh2Si, iPr3Si) and [M(R′3SiOC≡COR)(depe)2X] (R = Et, Ac; R′3Si = tBuPh2Si, iPr3Si, Me3Si) from reactions of the siloxycarbyne precursors [M(COSiR′3)-(CO)(dmpe)2] and [M(COSiR′3)(CO)(depe)2] (M = Nb, Ta) with carbon-based electrophiles. The proper choice of carbon-based electrophile and reaction conditions is crucial in order to avoid oxidation of these low-valent metal complexes to [M(CO)2(dmpe)2X], which can occur competitively or exclusively.
