Unusual coordination mode of thiosemicarbazone ligands. A search for the origin

被引:155
作者
Basuli, F
Peng, SM
Bhattacharya, S [1 ]
机构
[1] Jadavpur Univ, Dept Chem, Inorgan Chem Sect, Kolkata 700032, W Bengal, India
[2] Natl Taiwan Univ, Dept Chem, Taipei 10764, Taiwan
关键词
D O I
10.1021/ic991083r
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Twelve mixed-ligand thiosemicarbazone complexes of ruthenium and osmium, ten of general formula [M(bpy)(2)-(bztsc-R)]ClO4, (M = Ru, Os; bpy = 2,2'-bipyridine, Hbztsc-R = benzaldehyde thiosemicacbazone) and two of type [M(bpy)(2)(actsc)]ClO4 (Hactsc = acetonethiosemicarbazone), have been synthesized and characterized. All the complexes are diamagnetic (low-spin d(6), S = 0) and in acetonitrile solution show several intense metal-to-ligand charge-transfer (MLCT) transitions in the visible region. Structures of Hbztsc-OMe, [Ru(bpy)(2)(bztsc-NO2)]ClO4 and [Ru(bpy)(2)(actsc)]ClO4 have been determined by X-ray crystallography. Benzaldehyde thiosemicarbazone exists in the thione form with the phenyl group trans to the hydrazinic nitrogen. The benzaldehyde thiosemicarbazone ligand coordinates to the metals through the hydrazinic nitrogen and sulfur with a bite angle of similar to 67 degrees, forming a four-membered chelate ring. However, the actsc ligand coordinates through the imine nitrogen and sulfur, forming a five-membered chelate ring with a bite angle of similar to 81 degrees. The difference in coordination modes of two types of thiosemicarbazone ligands, viz., bztsc-R and actsc, appears to result from the difference in steric bulk of the aryl and methyl group trans to the hydrazinic nitrogen. In acetronitrile solution they all show a reversible metal(II)-metal(III) oxidation in the range 0.18-0.58 V vs SCE followed by an irreversible oxidation in the range 1.11-1.60 V vs SCE. Two successive one-electron reductions of the coordinated bipyridine are also observed in the range -1.53 to -1.96 V vs SCE.
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页码:1120 / 1127
页数:8
相关论文
共 23 条
[1]   Unusual coordination mode of thiosemicarbazone ligand. Synthesis, structure, and redox properties of some ruthenium and osmium complexes [J].
Basuli, F ;
Ruf, M ;
Pierpont, CG ;
Bhattacharya, S .
INORGANIC CHEMISTRY, 1998, 37 (23) :6113-6116
[2]   Steric control of the coordination mode of the salicylaldehyde thiosemicarbazone ligand. Syntheses, structures, and redox properties of ruthenium and osmium complexes [J].
Basuli, F ;
Peng, SM ;
Bhattacharya, S .
INORGANIC CHEMISTRY, 1997, 36 (24) :5645-5647
[3]   ON THE CHARGE-TRANSFER SPECTRA OF IRON(II)-TRIS(2,2'-BIPYRIDYL) AND RUTHENIUM(II)-TRIS(2,2'-BIPYRIDYL) COMPLEXES [J].
CEULEMANS, A ;
VANQUICKENBORNE, LG .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1981, 103 (09) :2238-2241
[4]   PERHETERO-SUBSTITUTED ETHANES AND ETHYLENES .1. TETRAKIS(METHYLTHIO)ETHYLENE [J].
COLLINS, RC ;
DAVIS, RE .
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE, 1978, 34 (JAN) :283-285
[5]   THE ELECTRONIC-SPECTRUM OF FE(BPY)32+ AND OS(BPY)32+ [J].
DECURTINS, S ;
FELIX, F ;
FERGUSON, J ;
GUDEL, HU ;
LUDI, A .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1980, 102 (12) :4102-4106
[6]   STRUCTURAL VARIATIONS INDUCED BY CHANGES IN OXIDATION-STATE AND THEIR ROLE IN ELECTRON-TRANSFER - CRYSTAL AND MOLECULAR-STRUCTURES OF CIS-[RU(BPY)2CL2].3.5H2O AND CIS-[RU(BPY)2CL2]CL.2H2O [J].
EGGLESTON, DS ;
GOLDSBY, KA ;
HODGSON, DJ ;
MEYER, TJ .
INORGANIC CHEMISTRY, 1985, 24 (26) :4573-4580
[7]   EXCITED-STATE PROTON-TRANSFER OF RUTHENIUM(II) COMPLEXES OF 4,7-DIHYDROXY-1,10-PHENANTHROLINE - INCREASED ACIDITY IN EXCITED-STATE [J].
GIORDANO, PJ ;
BOCK, CR ;
WRIGHTON, MS .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1978, 100 (22) :6960-6965
[8]  
Hammett L. P., 1940, Physical organic chemistry
[9]  
reaction rates, equilibria, and mechanisms
[10]   ELECTROCHEMISTRY OF IRIDIUM-BIPYRIDINE COMPLEXES [J].
KAHL, JL ;
HANCK, KW ;
DEARMOND, K .
JOURNAL OF PHYSICAL CHEMISTRY, 1978, 82 (05) :540-545