Theoretical Studies on the M-M Bonding in Complexes [M2Cl4L2] and [M2Cl7L]- （M = Mo, Re; L = Ph2Ppy, （Ph2P）2py）

• 作者: PENG Qi XIE Mei-Xiang XU Xuan
• 来源期刊: 结构化学
• 学科: 化学
• 关键词: MO 自然键轨道 联结 密度泛函理论 可再生能源 复合物 相互作用 自旋状态
• 年，卷（期）: 2012,（9）
• 页码范围: 1287-1294
• 页数: 8页
• 分类号: O613.62|TP333.4
• 语种: 英文

摘要

The structures of complexes [MⅡ2Cl4L2] and [MⅢ2Cl7L]- （M = Mo, Re; L = Ph2Ppy, （Ph2P）2py） were calculated by using density functional theory （DFT） PBE0 method. Based on the optimized geometries, the natural bond orbital （NBO） analyses were carried out to study the nature of Re-Re and Mo-Mo bonds. The conclusions are as follows： the M-M distances in two-Ph2Ppy or （Ph2P）2py complexes [MⅡ2Cl4L2] are shorter than those in mono-Ph2Ppy or （Ph2P）2py complexes [MⅢ2Cl7L]- due to the double bridged N-C-P interactions. For singlet of all complexes, there is ReⅢ-ReⅢ or MoⅡ-MoⅡ quadruply bond in complex [Re2Cl7L]- or [Mo2Cl4L2], while only ReⅡ-ReⅡ or MoⅢ-MoⅢ triply bond in complex [Re2Cl4L2] or [Mo2Cl7L]-. The most stable spin state of 2 and 6, triplet, only contains triple ReⅢ-ReⅢ bond. Because the LPCl → BD＊Re-Re delocalizations weaken the Re-Re bond, the distance of ReⅢ-ReⅢ quadruple bonds in [Re2Cl7L]- is slightly longer than that of ReⅡ-ReⅡ triple bonds in [Re2Cl4L2]. Moreover, due to the delocalizations from the lone pair electrons of the remaining P’ atom to the M-M antibonding orbitals, the M-M distance in （Ph2P）2py complexes is slightly longer than that in Ph2Ppy complexes.