Theoretical Studies on the M-M Bonding in Complexes [M_2Cl_4L_2] and [M_2Cl_7L]- (M = Mo, Re; L = Ph

• 作 者: 许旋 彭琦 谢梅香
• 机 构: School of Chemistry & Environment, South China Normal University,Key Laboratory of Theoretical Chemi
• 出 处: 结构化学
• 发表日期: 2012年09期
• 关键词: complexes triple bonds remaining bridged shorter orbital singlet slightly bridgi

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.

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 The conclusions are as follows: the MM distances in two-Ph2Ppy or (Ph2P) 2py complexes [MⅡ2Cl4L2] are shorter than those in mono For singlet of all complexes, there is ReⅢ-ReⅢ or MoⅡ-MoⅡ quadruply bond in complex [Re2Cl7L] - or [Mo2Cl4L2], while only Re Ⅱ -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- ReⅢbond. Because of 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.