O-Sung Kwon

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.

A simple route to thiacrowns. Catalytic macrocyclization of thiirane by cationic manganese carbonyl complexes

Thiirane is transformed catalytically into the symmetric thiacrowns: 1,4,7,10-tetrathiacyclododecane, 12S4; 1,4,7,10,13-pentathiacyclopentadecane, 15S5; and 1,4,7,10,13,16-hexathiacyclooctadecane, 18S6, when treated with the manganese carbonyl monocations: [Mn(CO)4(L)(NCMe)]+, L=CO, PPh3, PMe2Ph and PEt3 at room temperature. 12S4 is the major thiacrown product. Considerable amounts of polymer are also formed. The phosphine-substituted catalysts are considerably more active and give better yields of the thiacrowns than the parent carbonyl, but they also give more polymer side product.

New evidence on the factors affecting bridging and semibridging character of carbonyl ligands. The structures of Mn2(CO)7(μ‐SCH2CH2S) and its phosphine derivatives Mn2(CO)7‐X(PMe2Ph)X(μ‐SCH2CH2S), × = 1,2

The new ethanedithiolate-dimanganese carbonyl complex, Mn 2 (μ-SCH 2 CH 2 S)(CO) 7 , 1, was prepared in 28% yield from the reaction of 1,2,5,6-tetrathiacyclooctane with Mn 2 (CO) 9 (NCMe). Complex 1 was characterized crystallographically. It contains two Mn(CO) 3 groups joined by a Mn-Mn bond of 2.6470(6) A in length, a dihapto-bridging ethanedithiolate ligand, and one strong semibridging CO ligand. The reaction of 1 with PMe 2 Ph yielded two derivatives: Mn 2 (μ-SCH 2 CH 2 S)(CO) 6 (PMe 2 Ph), 2, and gem-Mn 2 (μ-SCH 2 CH 2 S)(CO) 5 (PMe 2 Ph) 2 , 3a, in 48% and 6% yields, respectively. When heated at 40 °C, compound 3a was transformed into three isomers, iso-gem-Mn 2 (μ-SCH 2 CH 2 S)(CO) 5 (PMe2Ph) 2 , 3b, 1,2-Mn 2 (μ-SCH 2 CH 2 S)(CO) 5 (PMe 2 Ph) 2 , 3c, and cis-Mn 2 (μ-SCH 2 CH 2 S)-(CO) 5 (PMe 2 Ph) 2 , 3d. Compounds 3b and 3c were characterized by single-crystal X-ray diffraction analyses. The introduction of phosphine ligand into the complexes strongly affects the semibridging character of the carbonyl ligand.