An Amide-Linked Ferrocene Dimer, [(CH(3)CONHC(5)H(4))Fe(C(5)H(4)CONHC(5)H(4))Fe(C(5)H(4)CONHCH(3))]. Formation of Inter- and Intramolecular NH.O=C Hydrogen Bonds.

An amide-linked ferrocene dimer, [(CH(3)CONHC(5)H(4))Fe(C(5)H(4)CONHC(5)H(4))Fe(C(5)H(4)CONHCH(3))] (7), and a monomer, [(CH(3)CONHC(5)H(4))Fe(C(5)H(4)CONHCH(3))] (5), were synthesized, and their unique structures were determined by X-ray analysis. Amide planes are stacked with respect to each other in both crystal and dilute solution. These complexes form intermolecular NH.O=C hydrogen bonds in the crystal. On the other hand, they form intramolecular NH.O=C hydrogen bonds in a dilute solution as established by IR and (1)H NMR measurements. Spectral data suggest the presence of flapping structures in solution. Crystal data for 5: triclinic, P&onemacr;, a = 9.358(3) Å, b = 9.947(4) Å, c = 7.946(3) Å, alpha = 106.86(3) degrees, beta = 113.15(3) degrees, gamma = 76.59(3) degrees, V = 644.9(5) Å(3), Z = 2. 7.(1)/(2)EtCN: orthorhombic, Pna2(1), a = 7.467(4) Å, b = 14.048(4) Å, c = 23.400(5) Å, Z = 4.