Crystal structure, spectroscopy and theoretical studies of p-cyanobenzenosulfonamide and a Cu(II) complex (original) (raw)
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Inorganica Chimica Acta, 2003
A new benzimidazole based diamide ligand */N ,N ?-bis(2-methylbenzimidazolyl)-2,2?-oxydiethanamide (GBOA) */has been synthesized and utilized to prepare [Cu(GBOA)Cl 2 ] and [Cu I (NO 3)(GBOA)]. The complex [Cu(GBOA)Cl 2 ] has been characterized structurally. It crystallizes in monoclinic space group P 2 1 /n. The Cu(II) ion is in a slightly distorted square pyramidal coordination environment (t 0/0.167). Two trans bonded chlorine atoms, and two nitrogen atoms from two different molecules of benzimidazole ligand form the basal plane while the amide oxygen occupies the axial position of the square based pyramid. The structure of the complex is a one-dimensional, ligand-bridged polymer. Solid state X-band EPR spectrum of the complex shows a slightly broadened isotropic signal at g 0/2.0. The complexes display a quasi-reversible redox wave due to the Cu(II)/Cu(I) redox couple with E 1/2 values varying as NO 3 (B/Cl (. With respect to NHE, the E/ 1 2 / values are quite positive when compared to other benzimidazole based complexes (Inorg. Chim. Acta 151 (1988) 55). The catechol oxidase activity of [CuCl 2 (GBOA)] has been examined by studying the oxidation of various catechols in oxygen saturated methanol. Kinetic studies with [CuCl 2 (GBOA)] and DTBC (3,5-di-tertbutylcatechol) as substrate shows the initial rate of oxidation to be dependent on first power of catalyst concentration and squareroot of substrate concentration.
Characterization of Two New Copper(II) Complexes with Saccharinate and Benzimidazole as Ligands
Zeitschrift Fur Anorganische Und Allgemeine Chemie, 2000
The crystal structure of the complexes [Cu(sac) 2 -(bzim) 2 (H 2 O)] (1) and [Cu(sac) 2 (bzim)(H 2 O)(EtOH)]2 EtOH (2) (sac = saccharinate anion; bzim = benzimidazole; EtOH = ethanol) was determined by single crystal X-ray diffractometry. Complex 1 crystallizes in the monoclinic C2/c space group with Z = 8 whereas complex 2 belongs to the triclinic P1 space group with Z = 2. Room temperature mag-netic susceptibilities as well as electronic and IR spectra of both complexes were discussed. Their thermal behaviour was investigated by means of TG and DTA methods.
Studies of newly synthesized Cu(ii) complex with ligand 2-hydroxy-5-methylbenzoic acid hydrazide
2020
The ligand 2-hydroxy-5-methylbenzoic acid hydrazide has been synthesized during the research work. Thereafter, a coordination compound with Transition metal Cu (II) has been prepared by the reaction between selected transition metal ions Cu (II) with newly synthesized acid hydrazide ligand. Thereafter, solubility, melting point, conductivity and spectral analysis have been studied. After analysis six coordinated distorted octahedral structure of the complex has been confirmed.
Journal of …, 2009
The triphenyltin(IV) complexes of 4-[((E)-1-{2-hydroxy-5-[(E)-2-(2-carboxyphenyl)-1-diazenyl]phenyl}methylidene)amino]aryls (aryls = 4-CH 3 , 4-Br, 4-Cl, 4-OCH 3 ) have been synthesized and characterized by 1 H-, 13 C-, 119 Sn-NMR, ESI mass spectrometry, IR and 119m Sn Mö ssbauer spectroscopic techniques in combination with elemental analysis. The crystal structures of a representative carboxylate ligand (aryl = 4-CH 3 ) and three Sn complexes, viz., polymeric (Ph 3 Sn[O 2 CC 6 H 4 {N@N(C 6 H 3 -4-OH(C(H)@ NC 6 H 4 X-4))}-o]) n (X = Me (1) and Br (2)) and dimeric (Ph 3 Sn[O 2 CC 6 H 4 {N@N(C 6 H 3 -4-OH(C(H)@NC 6 H 4 X-4))}-o]) 2 (X = OMe (4)) complexes are reported. The coordination environment in each complex is trigonal bipyramidal trans-Ph 3 SnO 2 . A single zwitterionic carboxylate ligand bridges adjacent Sn atoms via the carboxylate and phenoxide O atoms.
2014
The synthesis and characterization of eleven new Cu(II) and Co(II) complexes is reported. The complexes were characterized by elemental analyses, infrared and electronic spectra. Copper(II) with 3-methylthiophene-2-carboxylic acid (HMTK) forms a dinuclear complex of the acetate type [Cu 2 (MTK) 4 (H 2 O) 2 ]. By reaction of this complex with 2-metylfuro[3,2-c]pyridine (MeFP), not only acetate type complexes [Cu 2 (MTK) 4 L 2 ] (L= FP, MeFP) were obtained, but also monomeric complex [Cu(MTK) 2 (FP) 2 ]. In the cases of [1]benzofuro[3,2-c]pyridine (BFP) and 2-(3-trifluoromethylphenyl)furo[3,2-c]pyridine (CF 3 FP) only monomeric complexes [Cu(MTK) 2 L 2 ] (L = BFP, CF 3 FP) were obtained. It is possible to observe, that with increasing amount of the ligand, the yield of monomeric complexes increases too. In monomeric complexes, the carboxylic group of anionic MTK binds to atom Cu(II) by asymmetrically chelating O,O-coordination. The crystal structure of the complex [Cu(MTK) 2 (MeFP) 2 ] was determined by X-ray single crystal structure analysis. The copper(II) atom lies in the crystallographic centre of symmetry in an distorted tetragonal-bipyramidal arrangement. The structure of this complex confirms an asymmetric chelate coordination of the carboxylic group. HMTK and Cobalt(II) form coordination compound [Co(H 2 O) 6 ](MTK) 2 with assumed ionic mode of coordination of anionic MTK. With furopyridines monomeric complexes [Co(MTK) 2 L 2 ] (L= FP, MeFP, BFP, CF 3 FP) with distorted octahedral coordination polyhedron around Co(II), were formed.
Four copper(II) and three zinc(II) coordination compounds with bis(1-methylimidazol-2-yl)ketone (BIK) of general formula X(BIK) 2 Y 2 (X = Cu(II), Zn(II), while Y = Cl, Br, NO 3 or ClO 4 ) were synthesized and characterized by elemental analysis and FTIR spectroscopies to be compared with the literature data. As a follow-up of our previous thermoanalytical studies on imidazole-substituted coordination compounds, the thermal behaviour of the synthesized Cu(II) and Zn(II) BIK complexes was investigated using thermogravimetry, where three consecutive releasing steps were ascribed to a complex decomposition process. All the complexes investigated showed the same reaction mechanisms, identified on the basis of the percentages of mass loss calculated from the TG curves. The decomposition mechanisms were confirmed by EGA analysis, performed by coupling the TG analyzer to a MS spectrometer. In particular, the first step is ascribed to the release of two anions, followed by the loss of four methyl groups (side chains) and two bridge-carbonyl groups. The residual tetra-imidazole copper(II) or zinc(II) compound decomposes in a final step to give the metal(II) oxide as the final residue. Both the initial decomposition temperatures and the kinetic rate constants associated to the first decomposition step indicated a higher stability of the Cu(BIK) 2 Y 2 complexes with respect to the corresponding Zn ones. As far as the effect of the presence of the anion on the thermal stability is concerned, it can be demonstrated that both the perchlorate Cu(II) and Zn(II) complexes have the lower thermal stability (lower E values), while the thermal stabilities of the bromide, chloride and nitrate Cu(II) and Zn(II) complexes are substantially comparable. Finally, the model mechanism that shows the best fit between theoretical and reconstructed g(˛) vs. ˛ dependencies for the first decomposition step is, as showed in a previous paper for the analogues Mn(II) complexes, the three-dimensional diffusion model (D3). Selection of the best kinetic triplet associated to the first decomposition step was successfully validated by comparing the experimental and reconstructed portion of the TG curves of Cu(BIK) 2 (NO 3 ) 2 within the corresponding temperature interval.
2002
Stable CUI and Cu" complexes with the novel ligand 1,6-bis(2-benzimidazolyl)-2,5-dithiahexane [BBDH, (C7H5N2-CH2-S-CH2-),] have been prepared. The bulky nature of the ligand prevents planar four-coordination of Cu". The X-ray structure of [Cu(BBDH)CI]C1.2C2H50H shows that CUI' is in a distorted trigonal-bipyramidal coordination geometry consisting of two axial benzimidazole N atoms and two thioether S atoms and a C1-ion as equatorial ligands. The compound crystallizes in the monoclinic space group P21/c with a = 14.930 (3) A, b = 17.109 (4) A, c = 10.774 (2) A, 0 = 97.23 (2) O , V = 2730 A3, dmd = 1.43 (1) g ~m-~, and dd = 1.414 g cm-3 for Z = 4. The structure was solved by direct methods and refined with use of full-matrix least-squares techniques. The residual R value was 0.07 1 for 3023 independent reflections (I > 1,96[u(I)]] whose intensities were measured on an automatic diffractometer. The ESR and ligand field spectra of solid Cu" BBDH compounds are consistent with a trigonal-bipyramidal coordination geometry. The spectroscopic data of solutions indicate a change in coordination geometry compared to that in the solid state. The NMR spectra of CUI BBDH compounds suggest binding of benzimidazole N atoms to the metal.