Synthesis and Molecular Structure of [Fe(4)(CO)(10)(mu(4)-O)(kappa(K)2-dppn)] (dppn=1,8-bis(diphenylphosphino)naphthalene): A Missing Piece in the [M(4)(CO)(12)(mu(4)-E)](n-) (M = Fe, Ru:E = C, N, O; n=2, 1, 0) Puzzle
Reaction of Fe(3)(CO)(12) with 1,8-bis(diphenylphosphino)naphthalene (dppn) yields the tetranuclear oxide cluster [Fe(4)(CO)(10)(mu(4)-O)(kappa(2)-dppn)] (1), which has been crystallographically characterized. It is a member Of the [M(4)(CO)(12)(mu(4)-E)](n-) series of butterfly clusters, being a close relative of the unknown "missing link" [Fe(4)(CO)(12)(mu(4)-O)] (2). In Order to Understand the stability of' I relative to 2, we have carried out DFT calculations oil [Fe(4)(CO)(10)L(2)(mu(4)-O)] (L = CO, PMe(3), PPh(3); L(2) = dppn), which suggest that I is best considered its a combination of [Fe(3)(CO)(9)O](2-) and [Fc(CO)(dppn)](2+) fragments.