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Carbon-sulfur bond cleavage with a loss of stereochemistry in the ring opening of trans-2,4-diphenylthietane by Os{sub 3}(CO){sub 10}(NCMe){sub 2}

Journal Article · · Organometallics
;  [1]
  1. Univ. of South Carolina, Columbia, SC (United States)
The reaction of Os{sub 3}(CO){sub 10}(NCMe){sub 2} with trans-2,4-diphenylthietane (2,4-DPT) at 25 {degrees}C resulted in the formation of two isomers, cis- and trans-Os{sub 3}(CO){sub 10}[{mu}SC(H)PhCH{sub 2}C(H)Ph] (1), in a combined yield of 76%. The cis product was characterized by single-crystal X-ray diffraction analysis and was found to contain a thiametalladiphenylcyclopentane ring formed by the opening of the thietane ring. The cis and trans isomers differ in the orientation of their phenyl substituents. The isomers are formed in approximately equal amounts in the early stages of the reaction, but the trans isomer subsequently slowly isomerizes to the cis isomer. The observed loss in stereochemistry at the carbon center is attributed to a stepwise ring-opening mechanism. When compound 1 was heated to 97 {degrees}C under a CO atmosphere, five compounds were formed: Os{sub 3}(CO){sub 10}[{mu}-SC(H)PhC(H)=C(H)Ph]({mu}-H) (2) (22%), Os{sub 2}(CO){sub 7}[{mu}-SC(H)(C{sub 6}H{sub 4})CH{sub 2}CH{sub 2}Ph] (3) (11%), Os{sub 3}(CO){sub 11}[{mu}-SC(H)PhCH{sub 2}C(H)Ph] (4) (39%), H{sub 2}Os{sub 6}(CO){sub 17}({mu}{sub 3}-S)({mu}{sub 4}-S) (5) (a trace amount), and Os{sub 3}(CO){sub 12}. Compounds 3 and 5 and the known compound Os{sub 3}(CO){sub 9} ({mu}{sub 3}-S) (6) were obtained in better yields by heating 2 to 125 {degrees}C in octane solvent. Compounds 2-4 were characterized by IR, {sup 1}H NMR, and single-crystal X-ray diffraction analyses. Compound 2 is an isomer of 1 and contains a diphenylpropenethiolate and hydride ligand formed by a {open_quotes}{beta}-elimination{close_quotes} transformation of the ring system in 1. The mechanism of this transformation was not established. Compound 3 contains only two metal atoms and an ortho-metalated phenyl ring. Compound 4 is a CO adduct of 1 formed by the cleavage of the sulfur-bridged metal-metal bond. 21 refs., 6 figs., 13 tabs.
Sponsoring Organization:
USDOE
OSTI ID:
263715
Journal Information:
Organometallics, Journal Name: Organometallics Journal Issue: 1 Vol. 11; ISSN ORGND7; ISSN 0276-7333
Country of Publication:
United States
Language:
English