AMETHYL-3,4-DIATHIA-7,10-DIAZABICYCLO[5.3.0]DECANE AND ITS REACTION WITH OXOTRICHLOROBIS(TRIPHENYLPHOSPHINE)-RHENIUM(V)

The ligand molecule ramethyl-3,4-dithia-7,10-diazabicyclo[5.3.0]decane has been prepared and characterized by H-1 and C-13 NMR spectroscopy and by mass spectrometry. The protected analogue, N10-[(2'- ramethyl-3 ,4-dithia-7,10-diazabicyclo[5.3.0]decane dimethanol hemihydrate, was e xamined by the same techniques and also by X-ray crystallography. Crys tals were triclinic, P-1, a = 11.125(2), b = 11.986(2), c = 13.562(3) Angstrom, alpha = 103.54(3)degrees, beta = 90.29(3)degrees, gamma = 10 7.11(3)degrees, and Z = 2. The crystal was unstable in air at room tem perature, so measurements were made on a crystal sealed in a tube that contained methanol vapour. Intensities were measured with a Rigaku AF C6R diffractometer and monochromated CuK alpha radiation (lambda = 1.5 4178 Angstrom). The structure was solved by direct methods and refined to R = 0.1497, wR = 0.0655 based on 5000 independent reflections. The high residuals were caused by solvent disorder. Bond lengths and angl es were normal. The reaction of the ligand with oxotrichlorobis(triphe nylphosphine) rhenium(V) yielded an unexpected asymmetric complex, dim ercapto-3,6-diazaoctan-7-onato-N-3,N-6,S-1,S-8) rhenium(V). Crystals w ere monoclinic, P2(1)/n, a = 10.633(2), b = 11.221(2), c = 11.678(1) A ngstrom, beta = 116.10(1)degrees, Z = 4. Intensities were measured wit h a Siemens P4 diffractometer and monochromated MoK alpha radiation (l ambda = 0.71073 Angstrom). The structure was solved by the heavy atom method and refined to R = 0.0471, wR = 0.0340 based on 2866 unique ref lections. Most bond lengths and angles were normal. The Re=O distance of 1.681(5) Angstrom was longer than normal. It is postulated that thi s was caused by competitive pi bonding between the deprotonated amidic nitrogen atom and the rhenium atom, as shown by the short Re-N distan ce (1.997(6) Angstrom) compared to the equivalent distance for the ami ne nitrogen atom (Re-N, 2.151(4) Angstrom).