LINKAGE ISOMERIZATION OF MSCN(CDOH)(2)(CDO)BME TO MNCS(CDOH)(2)(CDO)BME (M = TC, RE) - CRYSTAL-STRUCTURES OF TCNCS(CDOH)(2)(CDO)BME, RENCS(CDOH)(2)(CDO)BME, AND RESCN(CDOH)(2)(CDO)BME

The 7-coordinate technetium(III) and rhenium(III) monocapped tris(diox ime) complexes [MX(dioxime)(3)BR] have been prepared in which the seve nth ligand, X, is thiocyanate or hydroxide (M = Tc, Re; R = Me, Et). B oth the N- and S-bound thiocyanate linkage isomers are produced during the syntheses, however, the S-bound complex isomerizes to the N-bound analogue. The synthetic routes employed allowed isolation of sufficie nt quantities of the technetium and rhenium S-bound isomers to be iden tified; however, full characterization was not possible. The linkage i somerization reaction of TcSCN(CDOH)(2)(CDO)BMe to TcNCS(CDOH)(2)(CDO) BMe was monitored in dichloromethane by UV-visible spectrophotometry, with four isosbestic points observed, consistent with the formation of a single product. The N-bound isomers for both Tc and Re, and the S-b ound isomer of Re were characterized by single-crystal X-ray diffracti on analysis. The two N-bound complexes were found to be isostructural. TcNCS(CDOH)2(CDO)BMe crystallized in the orthorhombic space group P2( 1)2(1)2(1) with a = 15.814(2) Angstrom b = 17.855(3) Angstrom, c = 17. 997(5) Angstrom, Z = 8, R = 0.054, and R-W = 0.057. ReNCS(CDOH)(2)(CDO )BMe crystallized in the orthorhombic space group P2(1)2(1)2(1) with a = 15.795(1) Angstrom, b = 17.843(2) Angstrom, c = 18.014(3) Angstrom, Z = 8, R = 0.054, and R-W = 0.073. In both cases two independent mole cules per unit cell were observed. ReSCN(CDOH)(2)(CDO)BMe crystallized in the monoclinic space group P2(i)/c with a = 10.0866(6) Angstrom, b = 26.301(2) Angstrom, c = 12.4592(7) Angstrom, beta = 100.5(1) deg, Z = 4, R = 0.100, and R-W = 0.141.