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Chemistry of [(1H-hydronaphthalene)Mn(CO)<INF>3</INF>]: The Role of Ring-Slippage in Substitution, Catalytic Hydrosilylation, and Molecular Crystal Structure of [(η<SUP>3</SUP>-C<INF>10</INF>H<INF>9</INF>)Mn(CO)<INF>3</INF>P(OMe)<INF>3</INF>]
- Source :
- Organometallics; September 27, 1999, Vol. 18 Issue: 20 p4114-4118, 5p
- Publication Year :
- 1999
-
Abstract
- Reaction of [(η<SUP>5</SUP>-C<INF>10</INF>H<INF>9</INF>)Mn(CO)<INF>3</INF>] (<BO>1</BO>) with L produced [(η<SUP>3</SUP>-C<INF>10</INF>H<INF>9</INF>)Mn(CO)<INF>3</INF>L] (<BO>2</BO>, L = P(OMe)<INF>3</INF>; <BO>5</BO>, L = CO) in high yields. X-ray structural analysis of <BO>2</BO> confirmed an η<SUP>3</SUP>-bonding mode of the 1-hydronaphthalene ring. Thermal treatment of <BO>2</BO> led to [(η<SUP>5</SUP>-C<INF>10</INF>H<INF>9</INF>)Mn(CO)<INF>2</INF>P(OMe)<INF>3</INF>] (<BO>3</BO>). The η<SUP>5</SUP>-1-hydronaphthalene ring in <BO>1</BO> is quite easily ring-slipped, η<SUP>5</SUP> ↔ η<SUP>3</SUP>. A kinetic study of the reaction of <BO>1</BO> with P(OMe)<INF>3</INF> indicates that formation of <BO>2</BO> is first order in <BO>1</BO> and first order in P(OMe)<INF>3</INF> with the following activation parameters: ΔH<SUP>&thermod;</SUP> = 6.9 ± 0.4 kcal/mol; ΔS<SUP>&thermod;</SUP> = −32.6 ± 1.5 eu. Quantitative comparison between the reactivity of the indenyl complex [(η<SUP>5</SUP>-C<INF>9</INF>H<INF>7</INF>)Mn(CO)<INF>3</INF>] with P(OEt)<INF>3</INF> and <BO>1</BO> with P(OMe)<INF>3</INF> at 130 °C shows that the rate constant for <BO>1</BO> is 2 × 10<SUP>6</SUP> times faster than that of the indenyl complex. The tremendous rate enhancement in <BO>1</BO> was rationalized as a stabilization of <BO>2</BO> by the second benzene ring. The facile ring-slippage in <BO>1</BO> has been utilized in the synthesis of [(η<SUP>6</SUP>-C<INF>10</INF>H<INF>8</INF>)Mn(CO)<INF>2</INF>P(OMe)<INF>3</INF>]BF<INF>4</INF> and in the catalytic hydrosilylation of ketones. Complex<BO> 1 </BO>is an effective catalyst for the hydrosilylation of alkyl and aryl ketones with Ph<INF>2</INF>SiH<INF>2</INF> as a silane source. The indenyl complex [(η<SUP>5</SUP>-C<INF>9</INF>H<INF>7</INF>)Mn(CO)<INF>3</INF>] has no catalytic activity in the hydrosilylation of ketones. The facile ring-slippage in the η<SUP>5</SUP>-1-hydronaphthalene ring plays a crucial role in the chemistry of <BO>1</BO>.
Details
- Language :
- English
- ISSN :
- 02767333 and 15206041
- Volume :
- 18
- Issue :
- 20
- Database :
- Supplemental Index
- Journal :
- Organometallics
- Publication Type :
- Periodical
- Accession number :
- ejs1154194