Coordination diversity of N-phosphoryl-N′-phenylthiourea (LH) towards CoII, NiII and PdII cations: Crystal structure of ML2-N,S and ML2-O,S chelates

Thiourea, PhNHC(S)NHP(O)(OPri)2 (LH) chelates of CoII, NiII, and PdII ions have been obtained and investigated by single-crystal X-ray diffraction, UV, IR, NMR spectroscopy, and EI mass-spectrometry. The unusual 1,3-N,S-coordination via sulfur and NP(O) nitrogen atoms has been found in the trans-square-planar NiL2 and PdL2 complexes, whereas the 1,5-O,S-coordination is realized in the tetrahedral CoL2 complex. DFT calculations have revealed significant stabilization of the 1,3-N,S-structures due to stronger crystal field and the NH-O{double bond, long}P hydrogen bonds. © 2006 Elsevier B.V. All rights reserved

Crystal structure and physico-chemical properties of cobalt(II) and manganese(II) complexes with imidazole-4-acetate anion

Crystal complexes of the general formula [M(4-iaa)(2)(H(2)O)(2)]H(2)O have been obtained from aqueous solutions containing a double excess of the sodium salt of imidazole-4-acetic acid (Na 4-iaa . H(2)O) with respect to the nitrates of cobalt(II) and manganese(II). The complexes have been characterized by X-ray studies, electronic UV-VIS-NIR spectra, IR spectra and the complex of manganese(II) by EPR spectra. In the present complexes the imidazole-4-acetate anion is a chelating ligand where an azomethine nitrogen atom of the imidazole ring and an oxygen atom of the carboxyl group are donor atoms. The immediate environment of the central ion in both complexes is described by distorted cis-octahedron. (C) 2003 Elsevier Ltd. All rights reserved

Search of structure and ligands exchange for palladium(II) complexes with N-allylimidazole; X-ray and solid-state/solution NMR studies

Two coordination compounds of palladium(II) with N-allylimidazole ((L)) of the general formula [PdL(4)]Cl(2) center dot 3H(2)O (1) and trans-[PdL(2)Cl(2)] (2) have been synthesized. The crystal and molecular structure of complexes 1 and 2 was established by single-crystal X-ray diffraction analysis. The X-ray structural data were supplemented by solid-state (13)C NMR measurements (CP MAS and PASS 2D). The 1D and 2D NMR studies in solution reveal that complex 1 is unstable at room temperature and undergoes reversible decomposition to 2. The method for how to preserve a complex with four allyl-imidazole ligands in solution is shown. (c) 2005 Elsevier B.V. All rights is reserved