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《Inorganica chimica acta》1988,154(2):201-207
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《Inorganica chimica acta》1987,127(1):95-101
The pentadentate ligand 2,6-diacetylpyridinedisemicarbazone, DAPSC, reacts with Cr(NO3)3·9H2O and forms two kinds of complexes. At pH=3, the ligand is singly-deprotonated and crystals of [Cr- (DAPSCH)(H2O)2](NO3)2·H2O (Ia) are obtained. Evaporation of a solution at pH=0, yields crystals of [Cr(DAPSC)(H2O)2](NO3)3·2H2O (II) in which the ligand is fully protonated. The reaction of DAPSC with UO2(O2CCH3)2 in methanol, followed by crystallization of the product from DMSO yields crystals of [UO2(DAPSC2H)(H2O)]·2DMSO (III) in which the ligand is fully deprotonated. Compound Ia is monoclinic, space group P21/n with a=11.746(1), b=14.752(2), c=11.866(1) Å,β=105.53(2)°, V= 1981(1) Å3 and Z=4. Compound II is monoclinic, space group, P21/n with a=38.000(3), b= 14.939(2), c=8.233(1) Å, β=96.12(2)°, V= 4647(1) Å and Z=8. Compound III is monoclinic, space group P21/n with a=18.048(2), b=15.207(2), c=8.842(1) Å,β=97.72(2)°, V=2405(1) Å3 and Z=4. The structures were refined using 2084, 4169 and 2516 reflections to R values of 4.4%, 7.8% and 4.8% respectively. 相似文献
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Hexa-coordinated chelate complex cis-[Ru(CO)2I2(P∩S)] (1a) {P∩S = η2-(P,S)-coordinated} and penta-coordinated non-chelate complexes cis-[Ru(CO)2I2(P∼S)] (1b-d) {P∼S = η1-(P)-coordinated} are produced by the reaction of polymeric [Ru(CO)2I2]n with equimolar quantity of the ligands Ph2P(CH2)nP(S)Ph2 {n = 1(a), 2(b), 3(c), 4(d)} in dichloromethane at room temperature. The bidentate nature of the ligand a in the complex 1a leads to the formation of five-membered chelate ring which confers extra stability to the complex. On the other hand, 1:2 (Ru:L) molar ratio reaction affords the hexa-coordinated non-chelate complexes cis,cis,trans-[Ru(CO)2I2(P∼S)2] (2a-d) irrespective of the ligands. All the complexes show two equally intense terminal ν(CO) bands in the range 2028-2103 cm−1. The ν(PS) band of complex 1a occurs 23 cm−1 lower region compared to the corresponding free ligand suggesting chelation via metal-sulfur bond formation. X-ray crystallography reveals that the Ru(II) atom occupies the center of a slightly distorted octahedral geometry. The complexes have also been characterized by elemental analysis, 1H, 13C and 31P NMR spectroscopy. 相似文献
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Mukesh Kumar 《Inorganica chimica acta》2008,361(6):1793-1796
The dicarbonyl and diphosphine complexes of the type (η5-C5H5)Fe(L)2ER3 (L2 = (CO)2 (a), (Ph2P)2CH2 (b); ER3 = CH3 (1a/b); SiMe3 (2a/b), GeMe3 (3a/b), SnMe3 (4a/b)) were synthesized and studied electrochemically. Cyclic voltammetric studies on the dicarbonyl complexes 1a-4a revealed one electron irreversible oxidation processes whereas the same processes for the chelating phosphine series 1b-4b were reversible. The Eox values found for the series 1a-4a were in the narrow range 1.3-1.5 V and in the order Si > Sn ≈ Ge > C; those for 1b-4b (involving replacement of the excellent retrodative π-accepting CO ligands by the superior σ-donor and poorer π-accepting phosphines) have much lower oxidation potentials in the sequence Sn > Si ≈ Ge > C. This latter oxidation potential pattern relates directly to the solution 31P NMR chemical shift data illustrating that stronger donation lowers the Eox for the complexes; however, simple understanding of the trend must await the results of a current DFT analysis of the systems. 相似文献
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Dimethyl platinum(II) complexes [PtMe2(NN)] {NN = bu2bpy (4,4′-di-tert-butyl-2,2′-bipyridine) (1a), bpy (2,2′-bipyridine) (1b), phen (1,10-phenanthroline) (1c)} reacted with commercial 3-bromo-1-propanol in the presence of 1,3-propylene oxide to afford cis, trans- [PtBrMe2{(CH2)3OH}(NN)] (NN = bu2bpy (2a), bpy (2b), phen (2c)). On the other hand, [PtMe2(NN)] (1a)-(1b) reacted with the trace of HBr in commercial 3-bromo-1-propanol to give [PtBr2(NN)] (NN = bu2bpy (3a), bpy (3b)). The reaction pathways were monitored by 1H NMR at various temperatures. Treatment of 1a-1b with a large excess of 3-bromo-1-propanol at −80 °C gave the corresponding methyl(hydrido)platinum(IV) complexes [PtBr(H)Me2(NN)] (NN = bu2bpy (4a), bpy (4b)) via the oxidative addition of dimethyl platinum(II) complexes with HBr. The complexes [PtBr(H)Me2(NN)] decomposed by reductive elimination of methane above −20 °C for bu2bpy and from −20 to 0 °C for bpy analogue to give methane and platinum(II) complexes [PtBrMe(NN)] (5a)-(5b) and then decomposed at about 0 °C to yield [PtBr2(NN)] and methane. When the reactions were performed at a molar ratio of Pt:RX/1:10, the corresponding complexes [PtBrMe(NN)] (5a)-(5b) were also obtained. The crystal structure of the complex 3b shows that platinum adopts square planar geometry with a twofold axis through the platinum atom. The Pt…Pt distance (5.164 Å) is considerably larger than the interplanar spacing (3.400 Å) and there is no platinum-platinum interaction. 相似文献
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