Tsai Yi-Chou, Chen Hong-Zhang, Chang Chie-Chieh, Yu Jen-Shiang K, Lee Gene-Hsiang, Wang Yu, Kuo Ting-Shen
Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC.
J Am Chem Soc. 2009 Sep 9;131(35):12534-5. doi: 10.1021/ja905035f.
Heating K(4)Mo(2)Cl(8) and 2 equiv of Li[RC(NDipp)(2)] (R = H, Ph; Dipp = 2,6-i-Pr(2)C(6)H(3)) in tetrahydrofuran (THF) at 60 degrees C gives two paddlewheel type quadruply bonded dimolybdenum complexes, Mo(2)(mu-Cl)[Cl(2)Li(OEt(2))]mu-eta(2)-RC(N-2,6-i-Pr(2)C(6)H(3))(2) (R = H (1), Ph (2)). The Mo-Mo bond lengths of 1 and 2 are 2.0875(4) and 2.0756(8) A, respectively, indicating typical Mo-Mo quadruple bonds. Reduction of 1 and 2 by two electrons results in the isolation of their corresponding Mo-Mo quintuple bonded complexes, Mo(2)mu-eta(2)-RC(N-2,6-i-Pr(2)C(6)H(3))(2) (R = H (3), Ph (4)), and the Mo-Mo bond lengths dramatically decrease to 2.0187(9) A (3) and 2.0157(4) A (4), a consequence of the formation of the second delta bond and representing the shortest metal-metal bonds beyond the first row elements. The Mo-Mo quintuple bonding characters are corroborated by DFT calculations at the level of BP86/def2-TZVP and BP86/def2-TZVPP.
在60℃下，将K(4)Mo(2)Cl(8)与2当量的Li[RC(NDipp)(2)]（R = H，Ph；Dipp = 2,6 - i - Pr(2)C(6)H(3)）在四氢呋喃（THF）中加热，得到两种桨轮型四重键合的二钼配合物，Mo(2)(μ - Cl)[Cl(2)Li(OEt(2))]μ - η(2)-RC(N - 2,6 - i - Pr(2)C(6)H(3))(2)（R = H（1），Ph（2））。1和2的Mo - Mo键长分别为2.0875(4) Å和2.0756(8) Å，表明存在典型的Mo - Mo四重键。1和2通过双电子还原得到其相应的Mo - Mo五重键合配合物，Mo(2)μ - η(2)-RC(N - 2,6 - i - Pr(2)C(6)H(3))(2)（R = H（3），Ph（4）），Mo - Mo键长显著减小至2.0187(9) Å（3）和2.0157(4) Å（4），这是由于形成了第二个δ键，代表了第一排元素之外最短的金属 - 金属键。在BP86/def2 - TZVP和BP86/def2 - TZVPP水平的密度泛函理论（DFT）计算证实了Mo - Mo五重键的性质。
