Liu Lihua, Zakharov Lev N, Golen James A, Rheingold Arnold L, Watson William H, Hanna Tracy A
Department of Chemistry, Texas Christian University, P.O. Box 298860, Fort Worth, Texas 76129, USA.
Inorg Chem. 2006 May 15;45(10):4247-60. doi: 10.1021/ic060404d.
We report a series of calix[4]arene Mo(VI) dioxo complexes M2RC4MoO2 (M = alkali metal, R = H or Bu(t)) that were fully characterized by NMR, X-ray, IR, UV/vis, and elemental analysis. Molybdocalix[4]arene structures can be controlled via lower rim deprotonation, groups at para positions of calix[4]arene, and alkali metal counterions. Mono deprotonation at the lower rim leads to calix[4]arene Mo(VI) monooxo complexes RC4MoO (R = H, Bu(t), or allyl), and full deprotonation gives rise to calix[4]arene Mo(VI) dioxo complexes. Structural studies indicate that HC4 Mo(VI) dioxo complexes easily form polymeric structures via cation-pi interaction and coordination between different calixarene units. However, Bu(t)C4 Mo(VI) dioxo complexes tend to form dimers or tetramers due to steric hindrance of the tert-butyl groups at para positions in calixarene. The structures of the reduced side products A and C were determined by X-ray diffraction studies. The mechanism of RC4MoO formation from the reaction of calixarene monoanions with MoO2Cl2 appears to include the addition of a calixarene -OH group across a Mo=O bond.
我们报道了一系列杯[4]芳烃钼（VI）双氧配合物M2RC4MoO2（M =碱金属，R = H或Bu(t)），通过核磁共振、X射线、红外、紫外/可见光谱和元素分析对其进行了全面表征。钼杯[4]芳烃结构可通过杯[4]芳烃下缘的去质子化、杯[4]芳烃对位的基团以及碱金属抗衡离子来控制。下缘的单去质子化会生成杯[4]芳烃钼（VI）单氧配合物RC4MoO（R = H、Bu(t)或烯丙基），而完全去质子化则会产生杯[4]芳烃钼（VI）双氧配合物。结构研究表明，HC4钼（VI）双氧配合物容易通过阳离子-π相互作用以及不同杯芳烃单元之间的配位形成聚合物结构。然而，由于杯芳烃对位叔丁基的空间位阻，Bu(t)C4钼（VI）双氧配合物倾向于形成二聚体或四聚体。通过X射线衍射研究确定了还原副产物A和C的结构。杯芳烃单阴离子与MoO2Cl2反应生成RC4MoO的机理似乎包括杯芳烃的-OH基团跨越Mo=O键的加成。
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