Transition Metal Derivatives of 1,10-Phenanthroline-5,6-dione: Controlled Growth of Coordination Polynuclear Derivatives

The synthesis and the characterization of several mono- and polymetallic derivatives of 1,10-phenanthroline-5,6,-dione (1) are presented. The reaction of 1 with M(CO)6 (M = Cr, Mo) gives compounds of general formula M(O,O0-C12H6N2O2)3, M=Cr (2), Mo (3).Compound 3 is also obtained starting from Mo(g6-CH3C6H5)2, whereas the reaction of Cr(g6-CH3C6H5)2 with 1 affords the ionic derivative [Cr(g6-CH3C6H5)2][C12H6N2O2] (4), which has been studied by EPR spectroscopy and DFT calculations.FeCl2(N,N0- C12H6N2O2)2 (6), is obtained by thermal decomposition of [Fe(N,N0-C12H6N2O2)3]Cl2 (5).Polymetallic compounds of general formula Cr[O,O0-C12H6N2O2-N,N0-MCl4]3,containing chromium and a Group 4 element M = Ti (7), Zr (8), Hf (9), are prepared from Cr(O,O0-C12H6N2O2)3 and the corresponding MCl4 or MCl4DME. Polynuclear derivatives of iron and chromium of formula [Fe(N,N0-C12H6N2O2-O,O0-CrCl2(THF)2)3][PF6]2 (10), and Cr[O,O0-C12H6N2O2-N,N0-FeCl2(THF)]3 (11), are obtained by the reaction of [Fe(N,N0-C12H6N2O2)3][PF6]2 with three equivalents of CrCl2(THF)2 and from Cr(O,O0-C12H6N2O2)3 and FeCl2(THF)1.5, respectively. Compound 11 reacts with 1 (3 equivalents in sym-C2H2Cl4 or 6 equivalents in ethanol) to give Cr[O,O0-C12H6N2O2-N,N0- FeCl2(N,N0-C12H6N2O2)]3 (12), and [Cr(O,O0-C12H6N2O2-N,N0-Fe(N,N0-C12H6N2O2)2)3]Cl6 (13), respectively.