Preferred Coordination Sites for Metal Fragments in σ,π-Bimetallic Complexes. Detailed Mechanistic Insight from Heteroatom, Bridging Ligand, Solvent, Temperature, and Pressure Effects on the Irreversible Exchange of Coordination Sites<sup>1</sup>
作者:Thomas A. Waldbach、Rudi van Eldik、Petrus H. van Rooyen、Simon Lotz
DOI:10.1021/om970494h
日期:1997.9.1
thiophene and selenophene ligands, (η1:η5-XCRCHCHCMn(CO)5)Cr(CO)3 (X = S, R = H (1), R = Me (2); X = Se, R = H (3)), were synthesized from (η5-XCRCHCHCLi)Cr(CO)3 and Mn(CO)5Hal (Hal = Cl-, Br-, CF3SO3-). The complexes 1−3 irreversibly convert at 0 °C in acetone into the complexes (η1:η5-XCRCHCHCCr(CO)5)Mn(CO)3 (X = S, R = H (4), R = Me (5); X = Se, R = H (6)) by exchanging coordination sites. The σ,π- exchange
新核配合物与σ,π桥接噻吩和硒吩配体,(η 1:η 5 -XCRCHCHCMn(CO)5)的Cr(CO)3(X = S,R = H(1)中,R =我(2) ; X =硒,R = H(3)),购自(η合成5 -XCRCHCHCLi)的Cr(CO)3和Mn(CO)5哈尔(HAL =氯- ,溴-,CF 3 SO 3 - )。配合物1 - 3不可逆地在0℃下在转换成丙酮配合物(η 1:η 5 -XCRCHCHCCr(CO)5Mn(CO)3(X = S,R = H(4),R = Me(5); X = Se,R = H(6))通过交换配位点。所述σ,配位点的π-交换是反应一阶过程和速率常数2是(3.8±0.1)×10 - 5和(1.1±0.1)×10 - 5个小号- 1在丙酮和环己烷分别在15°C下。该反应没有显着的压力依赖性。交换过程的活化熵为1和2为-16±6和-30±11 J /(mol K),