Synthesis, structure, and reactivity of polymetallic C3OMe complexes of the formula (eta(5)-C5Me5)Re(NO)(PPh3)(C equivalent to CC(OMe)=)M-m(CO)(n) (M/m/n=Re/2/9, Os/3/11): A new form of coordinated carbon in which a C-3 chain links two metals and spans a third
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
Reaction of (5-C5Me5)Re(NO)(PPh 3)(CCLi) with Re2(CO)10 and then Me3O+BF4- gives the trirhenium C3OMe complex cis-(5-C5Me5)Re(NO)(PPh 3)(CCC(OMe)=)Re(CO)4Re(CO)5 (3, 92%). An analogous reaction with Os3(CO)12 gives heterotetrametallic (5-C5Me5)Re(NO)(PPh 3)(CCC(OMe)=)Os3(CO)11 (4, 87%). NMR, IR, and crystallographic data (4) show substantial contributions by +Re=C=C=C(OMe)-M- resonance forms. Reaction of 3 and excess BF3 gas in toluene precipitates [(5-C5Me5)Re(NO)(PPh 3)(-1:3: 1-CCC)(Re(CO)4)Re(CO)5]+BF 4- (5, 64%). A crystal structure shows a slightly bent C3 moiety (152(4)) that binds a rhenium on each end and spans a third. NMR, IR, and bond length data show that 5 is best viewed as a completely metalated propargyl or PRe=CCC-Re(CO)5 adduct of Re(CO)4. It is likely derived by initial methoxide abstraction from 3 to give a ReCCCReRe species, followed by rearrangement. Reaction of (5-C5Me5)Re(NO)(PPh 3)(CCCCLi) with Re2(CO)10 and then Me3O+BF4- gives the C5OMe complex cis-(5-C5Me5)Re(NO)(PPh 3)(C CCCC(OMe)=)Re(CO)4Re(CO)5 (8, 44%). When 4 or 8 are treated with BF3 gas, Cx complexes are not detected. 1997 American Chemical Society.
