Synthesis and Decomposition of Alkyl Complexes of Molybdenum(IV) That Contain a [(Me3SiNCH2CH2)3N]3- Ligand. Direct Detection of α-Elimination Processes That Are More than Six Orders of Magnitude Faster than β-Elimination Processes
Synthesis and Decomposition of Alkyl Complexes of Molybdenum(IV) That Contain a [(Me3SiNCH2CH2)3N]3- Ligand. Direct Detection of α-Elimination Processes That Are More than Six Orders of Magnitude Faster than β-Elimination Processes
复制标题
含有 [(Me3SiNCH2CH2)3N]3- 配体的钼 (IV) 烷基配合物的合成和分解 直接检测比 β-消除过程快六个数量级的 α-消除过程。
DOI：
10.1021/ja970697x
复制
发表时间：
1997
影响因子：
15
通讯作者：
W. Reiff
中科院分区：
文献类型：
--
作者：
R. Schrock;S. Seidel;N. C. Mösch‐Zanetti;K. Shih;Myra B. O'Donoghue;W. M. Davis;W. Reiff
从[N3N]MoCl3-=[(N3N]3-=[(Me3SiNCH2CH2)3N]3-；R=Me、Et、Bu、CH2Ph、CH2SiMe3、CH2CMe3、环丙基、环丁基、环戊基、环己基、环戊烯基、苯基)合成了多种顺磁性钼配合物。所研究的几个样品都遵循居里−-维斯-S=1的行为，其固态磁矩在2.4-2.9μΒ之间降至5 0K，在∼5 0K以下，由于自旋−轨道耦合和零场分裂效应的共同作用，有效磁矩急剧下降.核磁共振谱与温度有关，这是由于主链“锁定”成一个C3对称构象的结果，也是居里−魏斯行为的结果。环戊基和环己基配合物表现出另一种依赖温度的流动行为，可归因于快速和可逆的α消除过程。在室温下，环戊基络合物消除α的速率常数为∼_(103)S~(-1)，消除速率常数为0.08×10~(-1)。
A variety of paramagnetic molybdenum complexes, [N3N]MoR ([N3N]3- = [(Me3SiNCH2CH2)3N]3-; R = Me, Et, Bu, CH2Ph, CH2SiMe3, CH2CMe3, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopentenyl, phenyl), have been prepared from [N3N]MoCl. The several that have been examined all follow Curie−Weiss S = 1 behavior with a magnetic moment in the solid state between 2.4 and 2.9 μΒ down to 50 K. Below ∼50 K the effective moments undergo a sharp decrease as a consequence of what are proposed to be a combination of spin−orbit coupling and zero field splitting effects. NMR spectra are temperature dependent as a consequence of “locking” of the backbone into one C3-symmetric conformation and as a consequence of Curie−Weiss behavior. The cyclopentyl and cyclohexyl complexes show another type of temperature-dependent fluxional behavior that can be ascribed to a rapid and reversible α-elimination process. For the cyclopentyl complex the rate constant for α-elimination is ∼103 s-1 at room temperature, while the rate co...