Small‐Molecule Activation with Molybdenum(0) Complexes Supported by Mixed Imidazol‐2‐Ylidene/Phosphanyl Hybrid Ligands – Electronic and Structural Consequences of Substituting a Phosphane by a Carbene Group
Small‐Molecule Activation with Molybdenum(0) Complexes Supported by Mixed Imidazol‐2‐Ylidene/Phosphanyl Hybrid Ligands – Electronic and Structural Consequences of Substituting a Phosphane by a Carbene Group
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混合咪唑-2-亚叉基/膦酰基杂化配体支持的钼(0)配合物的小分子活化——卡宾基团取代膦基的电子和结构后果
DOI：
10.1002/ejic.201300177
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发表时间：
2013
影响因子：
2.3
通讯作者：
F. Tuczek
中科院分区：
文献类型：
--
作者：
Christian Gradert;Jan Krahmer;F. Sönnichsen;C. Näther;F. Tuczek
通过采用一系列二齿和三齿的N-杂环卡宾（NHC）/膦配体，合成了新的钼（0）羰基配合物[Mo（CO）4（CP）] [1，CP = 3-（2-diphenylphosphanethyl）-1-ethylimidazole-2-ylidene]，fac-[Mo（CO）3（PCP）] [2，PCP = 1，3-bis [2-二苯基膦基乙基）咪唑-2-亚基]和fac-[Mo（CO）_3（CPC）] [3，CPC =双（1-乙基-3-亚乙基咪唑-2-亚基）苯基膦]。通过X射线结构分析和振动和NMR光谱结合DFT计算研究了化合物。为了比较，还合成了配合物[Mo（CO）4（CC）] [4，CC =二（1-乙基咪唑-2-亚基）甲烷]，fac-[Mo（CO）3（dpepp）] [5，dpepp =双（2-二苯基膦基乙基）苯基膦]和[Mo（CO）4（dppp）] [6，dppp = 1，3-双（二苯基膦基）丙烷]。与表现出金属-配体背键相互作用的膦供体相反，卡宾部分的π-受体相互作用被π-供体相互作用完全抵消。另一方面，发现膦和卡宾基团的σ-供体强度是相当的。这一结果对于小分子（例如，N2）进行了讨论。
By employing a series of mixed bi- and tridentate N-heterocyclic carbene (NHC)/phosphane ligands, the new molybdenum(0) carbonyl complexes [Mo(CO)4(CP)] [1, CP = 3-(2-diphenylphosphanylethyl)-1-ethylimidazol-2-ylidene], fac-[Mo(CO)3(PCP)] [2, PCP = 1,3-bis(2-diphenylphosphanylethyl)imidazol-2-ylidene], and fac-[Mo(CO)3(CPC)] [3, CPC = bis(1-ethyl-3-ethyleneimidazol-2-ylidene)phenylphosphane] have been synthesized. The compounds were investigated by X-ray structure analysis and vibrational and NMR spectroscopy in conjunction with DFT calculations. For comparison, the complexes [Mo(CO)4(CC)] [4, CC = di(1-ethylimidazol-2-ylidene)methane], fac-[Mo(CO)3(dpepp)] [5, dpepp = bis(2-diphenylphosphanylethyl)phenylphosphane], and [Mo(CO)4(dppp)] [6, dppp = 1,3-bis(diphenylphosphanyl)propane] have also been prepared and investigated. In contrast to the phosphane donors, which exhibiting metal–ligand backbonding interactions, the π-acceptor interactions of the carbene moieties are exactly cancelled by π-donor interactions. The σ-donor strengths of phosphane and carbene groups, on the other hand, are found to be comparable. The implications of this result with respect to the activation of small molecules (e.g., N2) are discussed.