Phenanthroline complexes of the d(10) metals nickel(0), zinc(II) and silver(I) comparison to copper(I) species

Structural features and physical properties of dmphen (2,9-dimethyl-1,10-phenanthroline) complexes with d(10) metals Zn-II, Ni-0 and Ag-1 were determined. These, together with the more well-known Cu-I compounds, constitute a rare example of an Ni-0, Cu-I, Zn-II isoelectronic, isostructural series. The first homoleptic zinc dmphen compounds [ZnNO3(dmphen)(2)]NO3 (1) and Zn(dmphen)(2)(BF4)(2) (2) were prepared. Their structures were determined by X-ray crystallography. Compound 1 is five-coordinate, with one nitrate ion coordinated. Compound 2, of the same stoichiometry as 1, exhibits the pseudotetrahedral, four-coordinate Zn(dmphen)(2)(2+) cation, which is isoelectronic and isostructural with the more well known Cu(dmphen)(2)(+) cation. Ni(dmphen)(2) (4) was prepared for the first time. Reaction of Ni-0(cyclooctadiene)(2) with dmphen in ethanol or tetrahydrofuran gave crystals of dark blue Ni-0(dmphen)(2) (4). NMR experiments show that 4 is diamagnetic, with chemically equivalent dmphen ligands. From this species, by reaction with dichloromethane, Ni-2(dmphen)(2)Cl-4 (5) was obtained. In this compound each nickel atom bears one terminal chloride ligand and the two nickel atoms are connected by two mu-chlorine atoms. Finally, Ag(dmphen)(2)BF4 (6) was prepared, which now extends the isostructural series described above to a second-row transition metal. The structure of this compound was determined by X-ray crystallography. (C) 1997 Elsevier Science Ltd.