Structural Variety Of Iron Carbonyl Clusters Featuring Ferrocenylphosphines

The reaction chemistry of Fe-2(CO)(9) (10) with ferrocenenyl dichlorophosphines of different substitution is discussed. Single FcPCl(2), (5) as well as 1,1'- (6) and 1,2- (9) difunctionalized phosphines were used, of which 6 and 9, were prepared in a novel straightforward synthetic process. Substrate 5 gave butterfly-shaped Fe-2(CO)(6)(mu(2)-Cl)(mu(2)-PFcCl) and Fe-2(CO)(6)(mu(2)-PFcR(1))(mu(2)-PFcR(2)) (R-1, R-2=Cl, H). In addition, nido-Fe-3(CO)(10)(mu(3)-PFc) and nido-Fe-3(CO)(9)(mu(3)-PFc)(2) were obtained. 1,1'-Functionalized 6 bridges both ends of the Fe-2(CO)(6) entity. Therein, the so far smallest non-binding P...P distance (2.7674(12) angstrom) between both 1,1'-substituents is observed. Additionally, an 'organometallic octabisvalene', containing two [2]ferrocenophane entities was obtained. The eight-membered cyclic structure is twisted by 35.31(9)degrees regarding their ferrocenyl axis. Usage of 1,2-(PCl2)(2) functionalized 9 produced two isomers of a P-P connected dimer, which coordinates towards two independent Fe-2(CO)(6) fragments in a novel mu,mu',kappa(8) or bis(mu,kappa(4)) fashion, resulting in a meso isomer with a planar core, and a racem mixture, possessing a pocket-type structure. The latter shows the so far shortest observed P...P distance of 2.950(7) angstrom between two ortho P atoms of a ferrocenyl backbone. The results confirm that the geometric properties of ferrocenyls featuring 1,1'- and 1,2-substitution patterns are not comparable with phenyl-based analogues. X-ray single crystal solid state structures, and DFT calculations were carried out.