Synthesis, structure, and spectroscopic properties of fac-[TcICl(CO)3(bpy)] (bpy=2,2'-bipyridine)

The 1:1 reaction of ((C2H5)4N)2[fac-TcCl3)(CO)3] with 2,2'-bipyridine (bpy) gave fac-[TcCl(CO)3(bpy)]([1]). The complex [1] is characterized on the basis of electronic absorption and 1H NMR spectra along with single crystal X-ray analysis. The complex [1] crystallizes in the orthorhombic space group Pca21 with a=25.027(3) A, b=6.5327(7) A, c=16.679(2) A, V=2726.9(6) A, Z=8, and R=0.0320. In [1], Tc(I) ion is coordinated by three carbonyls with the facial positions, one chloride, and one bpy ligand. The metal-to-ligand charge transfer transition band was observed at 354 nm in CH3CN solution. The transition energy of the metal-to-ligand charge transfer band for [1] is somewhat larger than that for the Re congener. (author)