Pentacarbonyl(2,6-diaminopyridine)chromium(0):: synthesis and molecular structure

Photolysis of hexacarbonylchromium(0) in the presence of 2,6-diaminopyridine in toluene solution at 10 degreesC yields pentacarbonyl(2,6-diaminopyridine)chromium(0), which could be isolated from solution as plate-like crystals and fully characterized by using the single crystal X-ray diffractometry and MS, IR, H-1 and C-13 NMR spectroscopy. The complex was found to have the 2,6-diaminopyridine ligand bonded to the chromium atom through one of the NH2 groups. A single crystal X-ray structure of the complex reveals that the coordination sphere around the chromium atom is a slightly distorted octahedron, involving five carbonyls and one 2,6-diaminopyridine ligand. Because of the steric requirement of 2,6-diaminopyridine the four equatorial carbonyl groups are bended away from the N-donor ligand. The pyridine plane makes an angle of 112.9(3)degrees with the OC-Cr-N bond axis. The Cr-C distances have values between 1.833(7) and 1.935(7) Angstrom. The Cr-N distance is 2.236(5) Angstrom. (C) 2004 Elsevier B.V. All rights reserved.