Amidine and guanidine complexes of manganese and molybdenum.: Crystal structure of (η-cyclopentadienyl)(N,N′-diphenylguanidino)- and (η-cyclopentadienyl)(N,N′,N"-triphenylguanidino)-dicarbonylmolybdenum(II)

Reactions of N,N'-diphenyl-and N,N',N "-triphenylguanidine with [MnBr(CO)(5)] gave cis-[MnBr{PhNC(NHR)-NHPh}(CO)(4)],fac-[MnBr{PhNC(NHR)NHPh}(2)(CO)(3)] and [Mn{PhNC(NHR)NPh}(CO)(4)] (R = H or Ph), the last complex being formed at higher temperatures with an excess of ligand. In reactions of these guanidines with [MoCl(eta-C5H5)(CO)(3)], HCl was eliminated and {Mo(eta-C5H5)(PhNC(NHR)NPh}(CO)(2)] complexes (R = H or Ph) formed. Crystal structures of these molybdenum complexes have been determined, revealing symmetrically chelating co-ordination of the guanidino ligands (in close semblance of corresponding amidino-complexes) with the four-membered metallacycle planar for R = Ph but unusually (by 21 degrees) folded for R =H due to hydrogen bonding of an uncommon type. Reaction of lithio-N,N'-di-p-tolylbenzamidine with [Mo(eta-C7H7)-(CO)(3)]BF4 yielded [Mo{eta-C7H7N(p-MeC6H4)C(Ph)NC6H4Me-p}(CO)(3)], consistent with nucleophilic attack at the ring, followed by nitrogen co-ordination at the metal by a pendant amidine group.