Dimolybdenum Complexes Containing Pairs of Bridging Polydentate Phospnine and Carboxylate Ligands

• Main Authors: Tseng Geo-Wei, 曾國偉
• Other Authors: Jhy-Der Chen
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/07835165283556425448

碩士 === 中原大學 === 化學學系 === 86 === This thesis discusses the chemistry of dimolybdenum complexes containing pairs of bridging polydentate phosphine and carboxylate ligands. The red complex [tr ans-Mo2(O2CCH3)2(μ-dppa)2](BF4)2, 1, was prepared by reaction of [trans-Mo2( O2CCH3)2(CH3CN)6](BF4) 2 with dppa (dppa = Ph2PN(H)PPh2) in THF. The reactions of Mo2(O2C(CH2)nCH3)4 with dppa and (CH3)3SiX (X = Cl or Br) offered the inter mediate complexes [trans-Mo2(O2C(CH2)nCH3)4(μ-dppa)2](X)2 ( X = Cl, n = 2, 2; X = Br, n = 2, 3; X = Cl, n = 10, 4; X = Cl, n = 12, 5 ) ,Their UV-vis and 31P {1H}-NMR spectra have been recorded and the structures of 1, 2 and 3 have been determined. Crystal data for 1 : space group P21/n, a = 12.234 (1)* , b = 17. 222 (1)* ,c = 13.266 (1) * , β= 95.529 (1)°, V = 2784.1 (6) * ^3, Z = 2, withfinal residuals R = 0.0513 and Rw = 0.0589. Crystal data for 2 : space group P21/n, a = 13.438 (1) * , b = 19.276 (1) * , c = 14.182 (1) * , β= 111.464 ( 1)°, V = 3418.9 (6) * ^3, Z = 2, with final residuals R = 0.0492 and Rw = 0.0695. Crystal data for 3 : space group P21/n, a = 13.579 (1) * , b = 19.425 (1) * , c = 14.199 (1) * , β= 111.881 (2)°, V = 3475.6 (6) * ^3, Z = 2, with final residuals R = 0.0703 and Rw = 0.0856. The diphosphine ligands are bridged tto the metal centers with almost eclipsed configurations around the metal-metalbond. The anions are located around the axial positions. The effect of the axial ligands on the metal-metal bond distance, 31P{1H} chemical shifts and δ→δ*transition energies will be discussed. The effect of the carboxylate ligands onthe　Mo-axial ligand distances will also be discussed. By reaction of (NH4)5Mo2Cl9　or Mo2Cl4(PPh3)2(CH3OH)2 with 1,1,1-Tris in methanol, the complex Mo2Cl4( 1,1,1-Tris)2 [1,1,1-Tris = 1,1,1-Tris (diphenylphosphino methyl)ethane ] can beprepared. The results of Uv-vis spectrum and 31P{1H} NMR spectra confirmed the bridging complex β-MoCl4(1,1,1-Tris)2 .