SYNTHESIS OF SULFIDO AND OXO COMPLEXES OF TECHNETIUM(V) AND RHENIUM(V) CONTAINING DITHIOLATO AND HYDROTRIS(1-PYRAZOLYL)BORATO LIGANDS - CRYSTAL-STRUCTURES OF DIMERIC ITHIOLATO)BIS(ETHENE-1,2-DITHIOLATO)TECHNETIUM(IV) AND AZOLYL)BORATO](ETHANE-1,2-DITHIOLATO)OXORHENIUM(V)

The new technetium(V) sulfido complexes [TcS(edt)2]- (1) and [TcSCl2(H B(pz)3)] (3) have been prepared and characterized. These species const itute the first examples of technetium complexes containing a terminal Tc=S bond. Complex 1 was obtained from [TcCl6]2- by reaction with eth ane- 1,2-dithiol (H2edt), while 3 was formed from [TCOC12(HB(PZ)3)] by atom transfer from B2S3. The rhenium analog of complex 3, [ReSCl2(HB( PZ)3)] (4), has been also prepared. In the synthesis of 1, the dimeric Tc(IV) complex [Tc2(edt)2(e=dt)2] (2) (e=dt = ethene-1,2-dithiolato) was isolated by precipitation. 2 represents the first example of a tec hnetium complex containing two terminal dithiolene and two bridged dit hiolato ligands. The conversion of ethane-1,2-dithiolato to ethene-1,2 -dithiolato in the reaction of preparation of 1 and 2 seems to play a key role in the formation of the [Tc=S]3+ core. The X-ray crystal stru cture of complex 2 showed the Tc atom in a trigonal prismatic array. 2 crystallizes in the triclinic space group P1BAR with cell parameters a = 8.624(4) angstrom, b = 8.064(4) angstrom, c = 8.303(5) angstrom, a lpha = 59.01(4)-degrees, beta = 61.22(5)-degrees, gamma = 65.07-degree s, V = 422.1 (I. 1) angstrom3, Z = 1, R = 0.052, and R(w) = 0.059 for 2065 observed reflections with F > 3sigma(F). The reactions of various monothiols and dithiols with [MCl6]2- and [MOCl2(HB(pz)3)] (M = Tc, R e) are also discussed. The X-ray crystal structure of one product of t hese reactions, namely the complex [ReO(edt)-(HB(PZ)3] (5), has been d etermined. 5 was monomeric with the Re atom in a distorted octahedral environment. It crystallizes in the monoclinic space group P2(1)/c wit h cell parameters a = 10.109(5) angstrom, b = 10.246(3) angstrom, c = 14.997(5) angstrom, beta = 94.01(3)-degrees, V= 1549.5(l.o) angstrom3, Z = 4, R = 0.039, and R(w) = 0.051 for 4292 observed reflections with F > 4sigma(F).