Electronic structure and spectroscopy of the cycloheptatrienyl molybdenum halide complexes [MoBrL2(?-C7H7)]+ (L2= 2CO, n= 0; L2= 2,2'-bipyridyl, n= 0 or 1)
Electronic structure and spectroscopy of the cycloheptatrienyl molybdenum halide complexes [MoBrL2(?-C7H7)]+ (L2= 2CO, n= 0; L2= 2,2'-bipyridyl, n= 0 or 1)
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环庚三烯基钼卤化物配合物 [MoBrL2(?-C7H7)] 的电子结构和光谱（L2= 2CO，n= 0；L2= 2,2-联吡啶，n= 0 或 1）
DOI：
10.1016/j.poly.2014.05.027
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发表时间：
2015
期刊：
影响因子：
2.6
通讯作者：
Roberts K
中科院分区：
文献类型：
--
作者：
Roberts K
在B3 LYP/Def 2-SVP水平上对半夹心环庚三烯基钼配合物[Mo（CO）3（η-C7 H7）]+，[1]+和[MoBrL 2（η-C7 H7）] n+（L2 = 2CO，n= 0，2; L2 = bpy，n= 0，3; L2 = bpy，n= 1，[3]+; bpy= 2，2′-bipyridine）进行了密度泛函理论计算.在所有情况下，C7 H7环的e2能级与金属dxy和dx 2-y2轨道之间都存在强的δ键相互作用，导致18电子闭壳层体系中具有明显dz 2特征的金属中心HOMO.用TD-DFT方法精确地再现了[1]+、2和3的电子紫外-可见光谱。配合物2和3的光谱归属表明，在390-770 nm范围内，配合物的吸收来自于一系列的MLCT（金属-配体电荷转移）或ILCT（配体间电荷转移）跃迁，其中羰基、C7 H7和2，2′-联吡啶配体作为金属或混合金属和溴化物给体的受体体系.金属为中心的，单电子氧化的3 3 [PF 6]的结果在几乎完全淬灭的可见光区MLCT/ILCT的3和替换可能产生的溴到金属LMCT（配体到金属电荷转移）过程中的弱过渡。
DFT calculations at the B3LYP/Def2-SVP level have been conducted on the half-sandwich cycloheptatrienyl molybdenum complexes [Mo (CO) 3 (η-C 7 H 7)]+,[1]+ and [MoBrL 2 (η-C 7 H 7)] n+(L 2= 2 CO, n= 0, 2; L 2= bpy, n= 0, 3; L 2= bpy, n= 1,[3]+; bpy= 2, 2′-bipyridyl). In all cases, strong δ-bonding interactions operate between the e 2 level of the C 7 H 7 ring and metal d xy and d x 2-y 2 orbitals resulting in a metal-centred HOMO with substantial d z 2 character in the 18-electron, closed shell systems. The experimental electronic UV–Vis spectra of [1]+, 2 and 3 are accurately reproduced by TD-DFT methods. For complexes 2 and 3, assignments made with the assistance of calculated spectra indicate that absorptions in the region 390–770 nm originate from a series of MLCT (metal–ligand charge transfer) or ILCT (inter-ligand charge transfer) transitions in which carbonyl, C 7 H 7 and 2, 2′-bipyridyl ligands act as acceptor systems from the metal or mixed metal and bromide donor groups. The metal-centred, one-electron oxidation of 3 to 3 [PF 6] results in almost complete quenching of the visible region MLCT/ILCT absorptions of 3 and replacement with weak transitions probably arising from bromide to metal LMCT (ligand to metal charge transfer) processes.