NUCLEOPHILIC-ADDITION OF WATER AND ETHANOL TO COORDINATED DI-(2-PYRIDYL)KETONE IN RHENIUM(V) AND TECHNETIUM(V) COMPLEXES - THE CRYSTAL-STRUCTURE OF LORO(HYDROXY-DI-(2-PYRIDYL)METHOXIDE)OXORHENIUM(V)

Complexes of general formula MOCl2[(C5H4N)2C(O)(OR)] (M = Re, Tc; R = H, Et) were prepared by the reaction of trans-ReOCl3(PPh3)2 and (n-Bu4 N)[TcOCl4] with di-(2-pyridyl)ketone (DPK) in ethanol (R = Et) under n itrogen and in benzene, containing trace amounts of water, in air (R = H). The compounds were characterized by elemental analysis, vibration al, optical and proton nuclear magnetic resonance spectroscopy. The ev idence suggests that the coordinated DPK ligand has undergone addition of water and ethanol at the carbonylic carbon atom, and that the (C5H 4N)2C(O)(OR) moiety acts as a uninegative, terdentate N,O,N-donor liga nd. The X-ray crystal structure of the complex ReOCl2[(C5H4N)2C(O)(OH) ] is also reported. Crystal data: C11H9N2O3Cl2Re, orthorhombic, space group Pcca; a = 14.935(5), b = 11.896(8), c = 14.937(11) angstrom, and U = 2653.8 (2.7) angstrom3 to give Z = 8 for D(calc) = 2.37 g cm-3. T he structure was solved by Patterson and Fourier methods and refined b y least-squares methods to R = 0.076. The complex has an Re=O bond dis tance of 1.67(2) angstrom, and a deprotonated diolate oxygen of the li gand is coordinated in the position trans to the oxo group.