| Summary: | 碩士 === 國立清華大學 === 化學系 === 102 === The quintuply-bonded dimolybdenum complex, Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (1), has a σ-bond, two π-bonds and two δ-bonds between two Mo atoms, so complex 1 can act as a supporting ligand to stabilize the group 10 metal atoms to form the δ-complexes, which show interesting reactivity toward organic compounds and small molecules. The reaction of 1 with Ni(PEt3)4 and two equiv of benzonitrile gives the complex, {μ-κ2-[κ2-NC(C6H4)-Ni(PEt3)2]}[μ-NC(H)Ph]Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (2). Complex 2 is formed via C-H bond cleavage of one molecule of benzonitrile. The reaction of 1 with Ni(PEt3)4 and phenylacetylene gives a δ-complex, [(PEt3)(η1-PhCC)Ni](μ-H){κ2-Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2} (3). In 3, 1 coordinates to the Ni(0) center by donation of its δ electrons, and the terminal C-H bond of phenylacetylene is cleaved and the resultant phenylacetylide and hydride coordinate to the Ni atom. Meanwhile, treatment of 2 with trimethylsilylacetylene affords a product containing a vinylidene group, [μ-η1-PhC(H)C][μ-η1-TMSCC][μ-Ni(PEt3)](μ-H){κ2-Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2} (4). Mixing 2 and two equivalents of phenylacetylene generates the complex, [η2-PhCCH][η1-Ni(PEt3)][μ-η2:η1:η1-PhCC(H)C(H)C(Ph)]Mo2[μ-κ2-HC-
(N-2,6-iPr2C6H3)2]2 (5), which is formed via a C-C coupling of two moleucles of PhCCH in a “tail-to-tail” mode.
The reaction of the quadruply-bonded dimolybdem complex, Mo2(μ-Cl)[(μ-Cl)2Li(OEt2)[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 with Pd(PEt3)3 gives the complex, (η1-PEt3)(η1-Cl)(μ-Cl)Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (6). In addition, the addition of 1 with trimethylsilylacetylene affords the complex, (μ-κ2-3,5-(Me3Si)2C4H2)Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (7), which is resulted from the “head-to-tail” C-C coupling of two moleucles of Me3SiCCH. The reaction of 1 with benzonitrile gives the complex, [μ-κ2-NC(Ph)C(Ph)N]Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (8), which is formed via a C-C coupling of two moleucles of PhCN. On the other hand, treatment of 1 with two equiv of mesityl nitrile results in the isolation of the complex, [η1-NC(Mes)]2Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)(N-2- iPr-6-CH(κ1-CH2)CH3-C6H3)][μ-κ2-HC(N-2,6-iPr2C6H3)2] (9), in which two mesityl nitrile groups terminally coordinate to Mo centers, mainly due to the steric effect. The reaction of 1 with white phosphorus leads to the isolation of the complex, (μ-η4︰η4-P4){Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2}2 (10), where the planar [P4]4- ligand bridges two fragments of 1. The reaction of 1 with ethyl benzoate generates the product, (μ-η2-1,2︰η2-4,5-PhCOOEt)Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (11), in which the phenyl group coordinates to two Mo centers in a face-on fashion. The reaction of 1 with [60]fullerene gives the complex, [(μ:μ:μ-η2:η2:η2:η2:η2:η2-C60]{Mo2[μ-κ2-HC(N-2,6-iPr2C6H3)2]2}3 (12), where three six-membered rings of the fullerene molecule coordinate to three moleucles of 1.
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