A highly reduced v(2)(3+) unit with a metal-metal bond order of 3.5

We report the isolation and structural characterization of the first four-bladed paddlewheel complex having an M(2)(3+) core in K(THF)(3)[V(2)(DPhF)(4)], where DPhF is the anion of N,N'-diphenylformamidine. This dark green, paramagnetic compound was obtained by reduction of diamagnetic, triply bonded V(2)(DPhF)(4) with KC(8). The V-V bond distance in K(THF)(3)[V(2)(DPhF)(4)] is 1.9295(8) A, 0.05 A shorter than that found in the V(2)(4+) species. The shortening of the bond, combined with a 15-line hyperfine splitting pattern in the EPR spectrum of K(THF)(3)[V(2)(DPhF)(4)], indicates that the unpaired electron is delocalized over the two vanadium atoms, giving rise to a bond order of 3.5.