Joseph L. Perrin

THE EFFECT OF A VINYL SUBSTITUENT ON THE RING OPENING OF A SUBSTITUTED TETRAHYDROTHIOPHENE AT A TRIOSMIUM CENTER

Abstract The reaction of Os3(CO)10(NCMe)2 with 2-vinyltetrahydrothiophene (VTHT) at 25°C yielded two products: Os3(CO)10[μ-SCH2CH2C(H)C(H)C(H)CH2](μ-H), 1 (38% yield) and Os2(CO)6[μ-η4-S(CH2)3CHCHCH2](μ-H), 2 (27% yield) after 48 h. Both products were characterized by single-crystal X-ray diffraction analysis. Compound 1 contains a triangular triosmium cluster with ten linear terminal carbonyl ligands, a hydride ligand and a hexadienethiolate ligand. Compound 2 contains only two mutually bonded osmium atoms, six linear terminal carbonyl ligands and a hexenylthiolate ligand that bridges the two osmium atoms via a bridging sulfur atom and three of the carbon atoms at the C-terminus of the hexenyl group. Ring opening of VTHT by a triosmium cluster occurs exclusively at the vinyl-substituted carbon atom.

BUTENEDITHIOLATE TRIOSMIUM CLUSTER COMPLEXES FROM THE REACTION OF OS3(CO)10(NCME)2 WITH 3,6-DIHYDRO-1,2-DITHIIN

The reaction of Os 3 (CO) 10 (NCMe) 2 with 3,6-dihydro-1,2-dithiin, , 1 at 0°C yielded two isomeric products Os 3 (CO) 10 (μ 3 -SCH 2 CHCHCH 2 S), 2 , and Os 3 (CO) 10 (μ-SCH 2 CHCHCH 2 S), 3 . Both compounds were characterized by a combination of IR, 1 H-NMR and single-crystal X-ray diffraction analyses. Both compounds contain open triosmium clusters with bridging 2-butene dithiolato ligands formed by cleavage of the S–S bond in 1 and one of the Os–Os bonds in Os 3 (CO) 10 (NCMe) 2 . In 2 one S atom bridges one of the Os–Os bonds while the other S atom bridges the open edge of the cluster. In 3 both S atoms bridge the open edge of the cluster. In 2 the butenedithiolato ligand has a folded conformation while in 3 this ligand is planar. Compound 2 is converted to 3 and the disomium compound Os 2 (CO) 6 (μ-SCH 2 CHCHCH 2 S), 4 when heated, but 3 is not converted to 4 under these conditions. Compound 4 contains a ‘saw horse’ structural arrangement with an Os–Os single bond. The two metal atoms are bridged by the two sulfur atoms of a folded 2-butenedithiolato ligand. Compounds 2 and 4 both exhibit dynamical NMR activity that is related to fluxionality of the butenedithiolato ligand. UV–vis irradiation of 3 results in the cleavage of the two C–S bonds with elimination of butadiene and formation of the disulfido complexes Os 3 (CO) 9 (μ 3 -S) 2 and Os 4 (CO) 12 (μ 3 -S) 2 .

The catalytic transformation of thiiranes to cyclic disulfides by tungsten carbonyl complexes

Abstract This report reviews our recent studies of the catalytic transformations of thiiranes and vinylthiiranes by tungsten pentacarbonyl complexes. Whereas the thiranes yield only macrocyclic polydisulfides, the latter reactions yield only the cyclic monodisulfides known as 3,6-dihydro-1,2-dithiins.

Synthesis and structural characterization of chiral thiacrowns: the crystal and molecular structure of (R,R,R)-2,6,10-trimethyl-1,5,9-trithiacyclododecane

Abstract The chiral polythioether macrocycles ( R , R , R )-2,6,10-trimethyl-1,5,9-trithiacyclododecane [( R , R , R )-Me 3 12S3] ( 8 ), and ( R , R , R , R )-2,6,10,14-tetramethyl-1,5,9,13-tetrathiacyclohexadecane, [( R , R , R , R )-Me 4 16S4] ( 9 ), have been synthesized from ( R )-2-methylthietane ( 7 ) by using the dirhenium carbonyl catalyst Re 2 (CO) 9 [( R )-2-SC(H)MeCH 2 CH 2 )] ( 10 ). The catalytic activity is low, 0.21 turnovers per hour, but is significantly above the uncatalyzed level. Compound 8 was characterized by a single-crystal X-ray diffraction analysis that was able to establish the absolute configuration.

Coordinations of vinyltetrahydrothiophene to a trirhenium cluster

Abstract The reaction of Re 3 (CO) 10 (NCMe) 2 (μ-H) 3 with 2-vinyltetrahydrothiophene (VTHT) at 25°C for 22 h yielded two products: Re 3 (CO) 10 (μ-H) 3 (μ-S(CH 2 ) 3 CHCHCH 2 ) ( 1 ; 50% yield), and Re 3 (CO) 9 (μ-H) 3 (μ-η 3 -S(CH 2 ) 3 CHCHCH 2 ) ( 2 ; 12% yield). Compound 1 exists in solution as a mixture of isomers in a dynamic equilibrium at room temperature. One of the isomers of 1 and 2 were characterized by single-crystal X-ray diffraction analyses. Compound 1 contains a triangular trirhenium cluster with ten linear terminal carbonyl ligands, three bridging hydride ligands and a bridging vinyltetrahydrothiophene ligand coordinated to two metal atoms by using both of the lone pairs of the electrons on the sulfur atom of the vinyltetrahydrothiophene molecule. Compound 2 contains a triangular cluster of three rhenium atoms and a triple-bridging vinyltetrahydrothiophene ligand that is coordinated to two of the rhenium atoms through the sulfur atom and a π-coordination of the vinyl group to the third metal atom. In both complexes there is a bridging hydride ligand across each of the three rhenium–rhenium bonds in the cluster. Facile interconversion of the two isomers of 1 was observed by 2D EXSYS 1 H-NMR spectroscopy. Compound 2 can be obtained from 1 in 98% yield via thermal decarbonylation by refluxing a solution in methylene chloride for 18 h.

The ring opening of 2-vinylthietane by a triosmium carbonyl cluster complex

Abstract The reaction of Os3(CO)11(NCMe) with 2-vinylthietane 2 at 25°C yielded two products: Os2(CO)6(η4-μ-SCH2CH2CHCHCH2) 3 (18% yield) and Os3(CO)10[η2-μ-O C(CH2CH CHCH2CH2S)] 4 (36% yield). Compound 4 was characterized by single crystal X-ray diffraction analysis. It contains a triangular triosmium cluster with ten linear terminal carbonyl ligands and a 3-hexeneoylthiolate ligand that bridges an open edge of the cluster through both the sulfur atom and the ketonyl group terminii. Compound 3 has only two osmium atoms, six carbonyl ligands and a bridging pentenylthiolate ligand. The ring opening of vinylthietane by a triosmium cluster occurs exclusively at the vinyl-substituted carbon atom.