Solid-state photochemical diag-lat isomerization of (eta(5)-C(5)H(4)R)Re(CO)(L)X(2) on the surface of silica gel

被引:12
作者
Cheng, L [1 ]
Coville, NJ [1 ]
机构
[1] UNIV WITWATERSRAND, DEPT CHEM, CTR APPL CHEM & CHEM TECHNOL, ZA-2050 WITWATERSRAND, JOHANNESBURG, SOUTH AFRICA
关键词
D O I
10.1021/om960726x
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Room-temperature visible illumination (200 W light source) of diag-(eta(5)-C(5)H(4)R)Re(Co,(L)X(2) (R = H, alkyl; L = CO, P(OR)(3); X = Br, I) adsorbed on silica gel results in isomerization of the complexes into the corresponding lateral isomers in good yield (typically >80%). For L = CO, the isomerization reactions occurred in the direction reverse to that found in solution in which lat-to-diag isomerization was observed. It was found that the ratio of diagonal to lateral isomers established on the surface of silica gel was influenced by both X and L, viz. (eta(5)-C(5)H(4)Me>Re(Co)[P(OR)(3)]Br-2 > (eta(5)-C(5)H(4)Me)Re(CO)(2)Br-2 > (eta(5)-C(5)H(4)Me)Re(CO)(2)I-2. Chemical removal of surface hydroxyl soups with Me(2)SiCl(2) revealed that only a monolayer of the rhenium complex chemically adsorbed on the surface of the silica gel underwent isomerization. A mechanism to rationalize the role of the silica surface hydroxyl groups is described.
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页码:591 / 596
页数:6
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