Milan Melnik

Bonding properties of thiocyanate groups in copper(II) and copper(I) complexes

Abstract The bonding properties of thiocyanate groups of over one hundred copper species, studied by X-ray analysis were analysed. It is shown that the bonding properties of thiocyanate groups in heterogeneous copper thiocyanate complexes depend on the size of the positive charge on the copper atom.

COPPER(II) COORDINATION COMPOUNDS: CLASSIFICATION AND ANALYSIS OF CRYSTALLOGRAPHIC AND STRUCTURAL DATA III. DIMERIC COMPOUNDS

Abstract This review summarizes the data for over nine hundred dimeric Cu(II) coordination compounds. There are several types of the bridges, from which doubly bridges by far prevail. The most common ligands are O− and N− donors. From the stereochemical point of view, a square-pyramidal arrangement with different degrees of distortion about Cu(II), is the most common. Several relationships were found between the Cu-Cu distances and the Cu-L-Cu bridge angle and the type of bridging, between the intra-ligand L-Cu-L ring angles and coordination numbers.

Comparison of the structural parameters in copper(II) acetate-type dimers containing distorted square pyramidal CuO4O and CuO4N chromophores

Abstract A survey of 123 of copper(II) acetate-type dimeric complex units, determined by X-ray diffraction in the crystal structures containing either a CuO 4 O or CuO 4 N chromophore, gave the following results. All the distorted square pyramidal coordination spheres contain a copper atom displaced 0.165–0.225 and 0.184–0.322 A from the basal O 4 plane in CuO 4 O and CuO 4 N chromophores, respectively. The Cu-Cu distances were in the range of 2.575–2.702 and 2.603–2.886 A for the CuO 4 O and CuO 4 N chromophores, respectively. The apical ligand atoms show large coefficients of variation for the distortion from the perpendicular to the basal O 4 plane. There is highly significant propensity for the copper(II) atoms to move out from the basal O 4 plane upon elongation of the Cu-Cu distance. Strong negative correlations were found between the CuOC and OCO angles. The most marked deviations for the observed parameters are caused by the bridges containing a halogenoacetate anion, leading to distorted trigonal bipyramidal geometry.

Copper(II) salicylideneglycinate complexes as potential antimicrobial agents

Abstract The reaction of an ethanolic solutions of N-salicylideneglycinatoaquacopper(II) hemihydrate with urea, pyridine, 2,4-dimethylpyridine, 3,5-dimethylpyridine, quinoline, 4-methylquinoline, isoquinoline, or 3-methylisoquinoline in an equimolar ratio resulted in solid products containing complexes of the type Cu(salgly)L with distorted square pyramidal coordination polyhedra. The products were characterized by elemental analysis, electronic and EPR spectra, and magnetic susceptibility measurements. Moreover, the crystal and molecular structure of N-salicylideneglycinatoureacopper(II) dimer was determined by single crystal X-ray diffraction methods. The copper(II) atoms are bridged by two phenolic oxygen atoms with a CuCu distance of 3.1093(11) A and CuOCu angle of 94.47(12)°. The antimicrobial effects have been tested on various strains of bacteria, yeasts and filamentous fungi.

Preparation, identification and thermal properties of (CH3CH2COO)2Zn·2L·H2O (L=thiourea, nicotinamide, caffeine or theorbromine)

Zinc carboxylates complexed with N-donor ligands have potential antifungal effects. The preparation, identification and especially the thermal properties of four hitherto non-characterized compounds of this group of general formula (CH3CH2COO)2Zn·2L·H2O are described in this paper. The experimental results are confronted with present knowledge on analogous compounds.ZusammenfassungKomplexe aus Zinkkarboxylaten mit N-Donorliganden besitzen potentielle fungizide Effekte. Vorliegend werden Herstellung, Identifizierung und insbesondere die thermischen Eigenschaften von vier bislang nicht beschriebenen Verbindungen dieser Gruppe der allgemeinen Formel (CH3CH2COO)2Zn·2L·H2O beschrieben. Den experimentellen Ergebnissen werden die vorhandenen Kenntnisse über analoge Verbindungen gegenübergestellt.

Structure, spectral and magnetic behaviours of tetrakis(flufenamato)(caffeine)(aqua) di copper(II)—first example of two non-equivalent ligands at the apex

Abstract The crystal and molecular structure of the tetrakis(flufenamato)(caffeine)(aqua)(dicopper)(II) Cu 2 (fluf) 4 (caf)(H 2 O), was determined by direct methods and Fourier techniques. The two copper(II) atoms are bridged by four carboxylate group, with the apical ligand of a water molecule around Cu(1), and a caffeine molecule around Cu(2). The spectral and magnetic properties are also discussed.

REVIEW: ZINC(II) COMPOUNDS: CLASSIFICATION AND ANALYSIS OF CRYSTALLOGRAPHIC AND STRUCTURAL DATA

Abstract Zinc has a relatively low abundance in nature (10−6 of the earths crust) but the chemistry of zinc compounds has been extensively investigated, and the relation-ships between structure and biomedical activity are of major importance. Zinc appears to bc one of the more biologically important metals,1 second only to iron among the heavy metals (i.e. excluding sodium, potassium, magnesium and calcium).

COPPER(II) COORDINATION COMPOUNDS: CLASSIFICATION AND ANALYSIS OF CRYSTALLOGRAPHIC AND STRUCTURAL DATA II. MONONUCLEAR-, HEXA-, HEPTA-AND OCTACOORDINATE COMPOUNDS

Abstract This review summarizes the data for over five hundred and fifty six-, seven- and eight-coordinate Cu(II) coordination compounds. The six-coordinate derivatives are mostly distorted tetragonal (elongation along a single C 4 axis). The seven-coordinate derivatives are only penta-gonal-bipyramidal with different degrees of distortion and the eight-coordinate complexes are dodecahedral. The most common ligands are O- and N-donors. There is a trend for the Cu-L distance to increase with covalent radius of the coordinated atom and also increasing coordination number. In general, Cu(II) compounds “prefer” a monoclinic class and are blue or green. Several relationships were found and discussed. The data are compared and discussed with those of four- and five-coordinate Cu(II) compounds.

Crystal and molecular structure of bis(niflumato)bis(3-pyridylmethanol)copper(II)

The crystal and molecular structure of the first copper(II) complex of (2-{[3-trifluoromethyl) phenyl]amino}-3-pyridinecarboxylate with 3-pyridylmethanol as neutral ligand was determined by X-ray analysis.

Crystal and molecular structure of copper(II)(pyridine-2,6-dicarboxylato)(2,6-dimethanolpyridine)

Abstract Copper(II)(pyridine-2,6-dicarboxylato)(2,6-dimethanolpyridine) has been prepared and studied by the single crystal X-ray diffraction methods at 293(2) K. The compound crystallises in an orthorhombic system, space group Pbcn with a=8.196(2), b=13.124(3), c=25.612(5) A, and Z=8 (R=0.0374 for 3175 independent reflections with I>2σ(I)). Crystal structure analysis revealed that the copper(II) atom is surrounded by two non-equivalent terdentate ligands making up an ‘all-trans’ elongated octahedral arrangement. In consequence of Jahn–Teller distortion, considerable differences are found between the ligands for the pyridine-2,6-dicarboxylate anion with the values Cu–N 1.892(3), Cu–O 2.033(2) and 2.063(2) A, while for the 2,6-dimethanolpyridine ligand the values are 1.943(3), 2.341(3) and 2.433(2) A. There is a relationship between the Cu–L bond distances and the five-membered metallocyclic rings (O–Cu–N). The data are compared and discussed with those found in familiar CuL2 compounds with the CuO4N2 chromophore. Based on the molecular structure, the electronic, IR and EPR spectra are discussed.