Tricarbonylrhenium(I) and -technetium(I) complexes with bis(2-pyridyl)phenylphosphine and tris(2-pyridyl)phosphine

(NEt4)(2)[Re(CO)(3)Br-3] or (NEt4)(2)[Tc(CO)(3)Cl-3] react with bis(2-pyridyl)phenylphosphine (PPhpy(2)) or tris(2-pyridyl)phosphine (Ppy(3)) under formation of neutral tricarbonyl complexes of the composition [M(CO)(3)X(L)] (M = Re, X = Br; M = Tc, X = Cl: L = PPhpy(2) or Ppy(3)). In all isolated products the ligands coordinate solely via two of their nitrogen atoms. All attempts to force a tripodal coordination of the phosphinopyridines failed. Removal of the bromo ligands from (NEt4)(2)[Re(CO)(3)Br-3] by the addition of AgNO3 in THF/water, and subsequent reaction of the resulting [Re(CO)(3)(THF)(3)](NO3) with Ppy(3) yielded the complex [Re(CO)(3)(NO3)(Ppy(3)-N,N')] with a monodentate coordinated nitrato ligand. The products have been chatacterized spectroscopically and by X-ray structure analyses. (C) 2008 Elsevier Ltd. All rights reserved.