New forms of coordinated carbon:: Wirelike cumulenic C3 and C5 sp carbon chains that span two different transition metals and mediate charge transfer

Reactions of (eta(5)-C5Me5)Re(NO)(PPh3)(C drop CLi) with W(CO)(6), Fe(CO)(5), or Mn(CO)(3)(eta(5)-C5HnCl5-n), followed by Me3O+ BF4-, give the heterobimetallic C3OMe complexes (eta(5)-C5Me5)Re(NO)(PPh3)(C drop CC(OMe)=)M(CO)(x)(eta(5)-C5HnCl5-n)(y) (M/x/y/n = 3, W/5/0/-; 4, Fe/4/0/-; 5, Mn/2/1/5; 6, Mn/2/1/4; 7, Mn/2/1/0). Spectroscopic and crystallographic (3) data indicate contributions by Re+=C=C=C(OMe)-M(-)resonance forms. Reactions of 4-7 and BF3 gas give the title compounds [(eta(5)-C5Me5)Re(NO)(PPh3)(CCC)M(CO)(x)(eta(5)-C5HnCl5-n)(y) (M/x/y/n = 9, Mn2/1/5; 10, Mn/2/1/4; 11, Mn/2/1/0; 12, Fe/4/0/-)]. Spectroscopic and crystallographic (9) data indicate dominant contributions by fully cumulated Re+=C=C=C=Mn resonance forms. Reactions of (eta(5)-C5Me5)Re(NO)(PPh3)(C drop CC drop CLi) with Mn(CO)(3)(eta(5)-C5Cl5), Mn(CO)(3)(eta(5)-C5Br5), or Fe(CO)(5), followed by Me3O(+) BF4-, give the C5OMe complexes (eta(5)-C5Me5)Re(NO) (PPh3)(C drop CC drop CC)(OMe)=>M(CO)(x)(eta(5)-C5X5)(y) (M/x/y/X= 16, Mn/2/1/Cl; 19, Mn/2/1Br; 20, Fe/4/0/-). However, Mn(CO)(3)(eta(5)-C5H5) does not react. Reaction of 16 and BF3 gives the C-5 complex [(eta(5)-C5Me5)Re(NO)(PPh3)(CCCCC)Mn(CO)(2)(eta(5)-C5Cl5)](+) BF4- (21)as a light-sensitive deep brown powder of >94% purity. IR and NMR data show a dominant Re+=C=C=C=C=C=Mn resonance form. UV-visible spectra of 9-11 and 21 show intense absorptions at 392, 396, 414, and 480 nm (epsilon 55 800, 50 900, 49 100, 60 500 M-1 cm(-1)), respectively, and weaker longer wavelength bands. These are believed to have appreciable rhenium-to-manganese charge-transfer character.