NUCLEOPHILIC RING-OPENING OF BRIDGING THIETANES IN OPEN TRIOSMIUM CLUSTER COMPLEXES

The complexes Os3(CO)9(mu-3-S)[mu-SCH2CMe2CH2] (1) and Os3(CO)9(mu-S)[mu-3-SCH2CH2CH2] (2) were obtained from the reactions of Os3(CO)10(mu-3-S) with 3,3-dimethylthietane (DMT) and thietane, respectively, at -42-degrees-C in the presence of Me3NO. Compound 1 was characterized by a single-crystal X-ray diffraction analysis and was found to contain a DMT group bridging two of the nonbonded metal atoms in the open cluster of three metal atoms by using both lone pairs of electrons on the sulfur atom. Compound 1 reacted with bis(triphenylphosphine)nitrogen(1+) chloride ([PPN]Cl) at 25-degrees-C to yield the salt [PPN]{Os3(CO)9(mu-SCH2CMe2CH2Cl)(mu-3-S)] (3; 76%), in which the chloride ion was added to one of the methylene groups of the DMT ring in a process that caused the ring to open by cleavage of one of the carbon-sulfur bonds. A 4-chloro-3,3-dimethylpropanethiolate ligand bridges the open edge of the anionic triosmium cluster. Compound 3 was converted to the neutral complex (Os3(CO)9[mu-SCH2CMe2CH2Cl](mu-3-S)(mu-H) (4) by reaction with HCl at 25-degrees-C. Compound 4 is structurally similar to 3, except that it contains a hydride ligand bridging one of the two metal-metal bonds. Compounds 1 and 2 react with HCl in CH2Cl2 solvent to yield the neutral compounds 4 and Os3(CO)9[mu-SCH2CH2CH2Cl](mu-3-S)(mu-H) (5) in 89% and 90% yields, respectively, in one step. Crystal data for 1: space group P2(1)/c, a = 9.690 (2) angstrom, b = 18.813 (4) angstrom, c = 13.932 (2) angstrom, beta = 109.41 (1)-degrees, Z = 4, 2112 reflections, R = 0.027. Crystal data for 3: space group P1BAR, a = 17.309 (2) angstrom, b = 17.768 (2) angstrom, c = 9.558 (1) angstrom, alpha = 104.99 (1)-degrees, beta = 103.64 (1)-degrees, gamma = 104.04 (1)-degrees, Z = 2, 3825 reflections, R = 0.025. Crystal data for 4: space group P1BAR, a = 12.500 (2) angstrom, b = 14.108 (2) angstrom, c = 6.4657 (6) angstrom, alpha = 102.380 (9)-degrees, beta = 99.20 (1)-degrees, gamma = 86.87 (1)-degrees, Z = 2, 2111 reflections, R = 0.024.