| Summary: | 博士 === 中原大學 === 化學系 === 87 === This thesis includes three chapters. The first chapter discusses syntheses, spectra and structures of quadruply bonded complexescontaining bridging h3-etp ligands (etp =Ph2PCH2CH2P(Ph)CH2CH2 PCH2PPh2). The second chapter discusses syntheses, spectra and stuctures of quadruply bonded complexes containing polydentate nitrogeneous ligands. The third chapter discusses novel cyclic hexanuclear complexes containing quadruply bonded units joined by m6-carbonate ions.The quadruply bonded complexes containing bridging acetate and polydentate phosphine ligands of the type Mo2(O2CCR3)X3(η3-etp) (R = H, X = Br, 1; R = F, X = Cl, 2; R = F, X = Br, 3; ) were prepared by reactions of Mo2(O2CCR3)2X2(PPh3)2 with etp in CH2X2 (X = Cl or Br). Their UV-vis and 31P{1H}-NMR spectra have been recorded and the structure of 1 has been determined by X-ray crystallography. The δ →δ* transition energy, 31P{1H}-NMR chemical shift and coupling constant were found to be dependent on the nature of the halogen atom . The though metal-metal quadruple bond coupling constant ︲3JP-Mo-Mo-P ︲ was determined to be 20 ± 2 Hz. The reaction of Mo2(O2CPrn)4 (X = Cl, 4; Br, 5) with PPh3 in THF, followed by addition of (CH3)3SiX (X = Cl, Br), afforded the complex Mo2(O2CPrn)2X2(PPh3)2. The quadruply bonded complexes containing bridging butyl acetate and polydentate phosphine ligand of the type Mo2(O2CPrn)X3(η3-etp)(X = Cl, 6; Br, 7) were prepared by reaction ofMo2(O2CPrn)2X2(PPh3)2 with etp. Their UV-vis and 31P{1H}-NMR spectra have been recorded and the structure of 4 and 5 have been determined by X-ray crystallography. The elongation of the alkyl group was found to have no effect on the δ→δ* energy, and 31P{1H}-NMR chemical shift. The reaction of trans-Mo2(O2CCR3)2X2(PPh3)2 with one equivalent of Hdpa (Hdpa = bis(2-pyridyl)amine) in CH2Cl2 afforded the complex cis-Mo2(O2CCR3)2X2(η2-Hdpa) (R = H, X = Cl, 8; R = H, X = Br, 9; R = F, X = Cl, 10, R = F, X = Br, 11). Layering of a Mo2(O2CCF3)4 solution in CH2Cl2 with Hdpa in ether produced red and yellow crystals, which were characterized to be Mo2(η2-dpa)4, 12, and Mo2(O2CCF3)4(η1-HO2CCF3)2 ． 2 Hdpa, 13, respectively. Complex 12 can also be prepared by reaction of trans-Mo2(O2CCR3)2X2(PPh3)2 with excess Hdpa. Their UV-vis and IR spectra have been recorded and the structures of 11,12 and 13 have been determined. The Hdpa ligand in 11 is coordinated to the metal centers through two terminal pyridine nitrogen atoms with a cis-N conformation. The dpa- ligands in 12 are bridged to the metal centers through one terminal nitrogen atom and the central nitrogen atom. The aligned-N conformation of the dpa- ligand is stabilized by both the intramolecular Mo---N and C-H---N interactions. In 13, the CF3COOH ligands coordinate to the metal centers in the axial positions with η1- bonding modes and the Hdpa molecules adapt cis-N conformations. The reaction of Mo2(O2CCF3)2Cl2(PPh3)2 with four equivalent of HDpyF (HDpyF = Bis(2-pyridyl)formamidine) in CH2Cl2 afforded the complex Mo2 (η2-DpyF)4 , 14. Complex 14 can also be prepared by reaction of Mo2(O2CCH3)4 with DpyF- in THF. Its UV-vis and IR spectra have been recorded and its structure of has been determined. The DpyF- ligand in 14 show two types of conformation ,i.e. cis and trans. Noticibly, while the cis conformation is stabilized by two intramolecular C-H---N interaction, the trans conformation is stabilized by one C-H---N and one Mo---N interactions. The reaction of Cr(CO)6 with one equivalent of HDpyF in THF afforded the complex Cr(CO)4(HDpyF), 15. The HDpyF ligand in 15 is chelated to the metal centers in a bidentate fashion.The reaction of Mo2(O2CCH3)2X2(PPh3)2 with two equivalents of bpma (bpma = 2, 2''-dipicolylamine) in THF afforded the complex [Mo2O2(μ-O)2(bpma)2][X]2(X = Cl, 16; Br, 17). The reaction of [Mo2(O2CCF3)2 (CH3CN)6][BF4]2 , 18 ,with two equivalents bpma in CH3CN afforded the complex [Mo2O2(μ-O)2(bpma)2][BF4]2. Layering of a [Mo2O2(μ-O)2(bpma)2][BF4]2 solution in CH2Cl2 with ether produced orange crystals, which were characterized to be [Mo2O2(μ-O)2(bpma)2][BF4][Cl], 19, Their UV-vis and IR spectra have been recorded and the structure of 16, 18, 19 have been determined by X-ray crystallography. The reaction of Mo2(O2CCF3)4with two equivalent H2tpda (H2tpda =Tripyridyldiamine) in THF afforded the complex (μ[Mo2O2-O)2(H2tpda)2][CF3COO]2, 20. All the structures of 16-20 contain bridging oxygen atoms and their Mo-Mo distances fall into the range for a Mo-Mo single bond. The reaction of [trans-Mo2(O2CCF3)2(CH3CN)6][BF4]2 with K2CO3 and dppa (dppa = N,N- Bis(diphenylphosphino)amine) in CH2Cl2 afforded the complex {[trans-Mo2(O2CCF3)2(μ-dppa)]3(m6-CO3)(m2-Cl)3}F, 21. Reaction of [trans-Mo2(O2CCF3)2(CH3CN)6][BF4]2 with K2CO3 and dppa in CH3CN, followed by addition of ZnX2 (X = Br or I) gave complexes of the type {[trans-Mo2(O2CCF3)2(μ-dppa)]3(μ6-CO3)(μ2-X)3}F (X = Br, 22; X = I, 23). The three quadruply bonded units in 21 - 23 are joined by CO32- ions and axially bridged by halide atoms. Each of the quadruply bonded units is bridged by a dppa ligand and two CF3COO- ligands which are trans to each other. Their UV-vis, IR and 31P{1H}NMR spectra have been recorded and their structures have been determined. They are the first cyclic, hexanuclear complexes containing quadruply bonded units joined by carbonate ions. The reaction of [trans-Mo2(O2CCF3)2(CH3CN)6][BF4]2 with and dppa in CH3CN, without addition of K2CO3, afforded the complex [trans-Mo2(O2CCF3)2 (dppa)2][BF4]2, 24.
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