| Increasing attention has been paid to dinuclear metal complexes, due to the significant cooperative effect of both metal centers on their reactivity and catalytic applications. Intensive study of these complexes will help to provide new catalysts with potential application prospects and expand organometallic chemical theory. In this dissertation, the reaction of the fulvenes and thienyl substituted cyclopentadienes with Fe(CO)5, Mo(CO)6 gave 15 corresponding dinuclear metal carbonyl complexes. Ten of them were characterized by X-ray diffraction and their structures were also discussed. The contents are listed as following:(1) The fulvene ligands C5H4CR1R2 C5H4CR1R2 [R1 = CH3, R2 = CH3 (1); R1 = R2 = C2H5 (3); R1, R2 (CH2)4 (4)]和Fe(CO)5 have been studied and three novel corresponding dinuclear metal carbonyl complexes have been obtained, and they are (η5-C5H4) [η3-C(CH2)2)]Fe2(CO)5 (6),C(C2H5)2[(η5-C5H4)Fe(CO)]2(μ-CO)2 (7),[(η5-C5H4)(C5H8) (η5-C5H3)(C5H9)Fe(CO)]2(μ-CO)2 (8). The complexes were characterized by IR spectra, 1H NMR, and elemental analysis, single crystal X-ray diffraction. It is a bridged dinuclear metal complex for complex 6. The fulvene ligand 1 coordinates to metal center byη5:η3. One iron atom is coordinated with cyclopentadienyl ligand byη5 model; the other iron atom is coordinated with allyl group byη3 model. It illustrates fulvenes undergo double bond isomerization, which coordinate with the iron atom in reactions. Complexes 7 and 8 are bridged dinuclear metal complexes. The cyclopentadienyl of the ligands coordinate with iron atom byη5, respectively. But the structures of the 7 and 8 are different. The data indicate that the bond length can be influenced by the model of the coordination.(2) Exchanged the Fe(CO)5 for Mo(CO)6. Five dinuclear metal carbonyl complexes were synthesized, [(η5-C5H4)CH(CH3)2Mo(CO)3]2 (9),[(η5-C5H4)CH(CH3)(C2H5)Mo(CO)3]2 (10),[(η5-C5H4) CH(C2H5)2Mo(CO)3]2 (11),[(η5-C5H4)C(C4H7)Mo(CO)3]2 (12),[(η5-C5H4)C(C5H9)Mo(CO)3]2 (13), respectively. They were characterized by IR spectra, 1H NMR, and elemental analysis. The molecular structures of complexes 10, 11, 12, 13 were determined by single crystal X-ray diffraction and have been discussed. The exocyclic double bond of fulvene ligands 2 and 3 were changed into the single bond in the reactions, for the complexes 10 and 11, but the fulvene 4 and 5 undergo double bond isomerization, for the 12 and 13. These indicated that fulvenes can be bounded to transition metal centers by diverse models.(3) Four thienyl substituted cyclopentadienyl ligands were designed and synthesized. The reactions of the ligands with Fe(CO)5, Mo(CO)6 gave the corresponding dinuclear metal carbonyl complexes [(η5-C5H4)C(CH3)2(C4H3S)]2Fe2(CO)2(μ-CO)2 (18),[(η5-C5H4) C(CH2CH3)2(C4H3S)]2Fe2(CO)2(μ-CO)2 (19),[(η5-C5H4)C(CH2)5(C4H3S)]2Fe2(CO)2(μ-CO)2 (20),[(η5-C5H4)C(CH3)2(C4H3S)Mo(CO)3]2 (21),[(η5-C5H4)C(CH3)(C2H5)(C4H3S)Mo (CO)3]2 (22),[(η5-C5H4)C(C2H5)2(C4H3S)Mo(CO)3]2 (23),[(η5-C5H4)C(CH2)5(C4H3S)Mo (CO)3]2 (24)。which were characterized by IR spectra, 1H NMR, and elemental analysis. The structures of complexes 20, 21, 24 were determined by single crystal X-ray diffraction. The structures of the complexes indicated that the two cyclopentadienyls of the complex 20 are trans. It has two types of carbonyl ligands, namely terminal and bridging, in its molecular structures. The structures of complexes 21 and 24 are very similar. The two cyclopentadienyls of the complexes 21, 24 are trans and are bound to Mo atoms centers byη5 models, respectively. The structures of the complexes showed that the intramolecular sulfur atom of the thienyl ring does not involve in coordination with the atoms. That is because the five-member heterocycle of thiophene is electron-rich; it is relatlively difficult for thiophene to become an anion by losing hydrogen. The lone pair in p orbital of sulfur atom overlaps with the every p orbital of the other four carbon atoms to form a closed conjugate system, resulting in reducing its ability to coordinate with metals. |
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