NONREDOX REACTIONS BETWEEN DIHYDROGEN SULFIDE AND CIS-RE2(MU-O2CR)2CL2(MU-DPPM)2 (R = CH3, C2H5, DPPM = PH2PCH2PPH2) - ISOLATION AND CHARACTERIZATION OF BIS(MU-HYDROSULFIDO) AND MU-GEM-DITHIOLATO COMPLEXES OF DIRHENIUM(II)

Nonredox reactions occur upon the exposure of cis-Re2(mu-O2CR)2Cl2(mu-dppm)2 (R = Me, Et; dppm = Ph2PCH2PPh2) to gaseous H2S in the presence of HBF4.Et2O to give either cis-Re2(mu-SH)2Cl2(mu-dppm)2, when THF or CHCl3 is used as the solvent, or the gem-dithiolato complexes cis-Re2(mu-S2CR1R2)Cl2(mu-dppm)2 and cis-Re2(mu-S2CHR2) Cl2(mu-dPPM)2 in the presence of ketones (R1R2CO) and aldehydes (R2CHO). These are the first examples of compounds in which the Re-Re triply bonded Re(mu-SH)2Re and Re(mu-S2CR1R2)Re moieties are present. The gem-dithiolatodirhenium complexes have been isolated in the following instances: mu-S2CR1R2 with R1 = R2 = CH3, CD3, C2H5 or C6H5, R1 = CH3 when R2 = C2H5, n-C3H7, or i-C3H7, and R1, R2 = -(CH2)5-or-(CH2)4-; mu-S2CHR2 with R2 = H, CH3, or C2H5. Single-crystal X-ray structural characterizations of cis-Re2(mu-SH)2Cl2(mu-dPPM)2 (1) and cis-Re2(mu-S2CMe2)Cl2(mu-dPPM)2 (2a) show that both complexes possess very similar cradlelike geometries and retain very short Re-Re interactions; the Re-Re distances of 2.2577 (5) angstrom for 1 and 2.2544 (6) angstrom for 2a accord with retention of the electron-rich Re-Re triple bond. Data for a crystal of composition Re2(SH)2Cl2(dPPM)2.0.5CH2Cl2 at +20-degrees-C are as follows: monoclinic space group P2(1)/c, a = 23.280 (3) angstrom, b = 13.040 (2) angstrom, c = 16.582 (3) angstrom, beta = 94.43 (2)-degrees, V = 5018 (2) angstrom3, and Z = 4. The structure was refined to R = 0.033 (R(w) = 0.037) for 5275 data with I > 3-sigma(I). Data for a crystal of composition Re2(S2CMe2)Cl2(dPPM)2.CH2Cl2 at +20-degrees-C are as follows: monoclinic space group P2(1)/n, a = 13.093 (5) angstrom, b = 23.807 (9) angstrom, c = 18.832 (4) angstrom, beta = 106.29 (2)-degrees, V = 5634 (6) angstrom3, and Z = 4. The structure was refined to R = 0.053 (R(w) = 0.069) for 5555 data with I > 3-sigma(I).