Vladimir N. Kokozay

Direct synthesis and crystal structure of zinc thiocyanate complexes with 1,4diazabicyclo(2,2,2)octane

Abstract A direct method of synthesis of zinc thiocyanate complexes with 1,4-diazabicyclo(2,2,2) octane (or triethylenediamine, Ten) is reported. The main peculiarities of interaction of zinc oxide with non-aqueous (methanol, acetonitrile, N,N-dimethylformamide = DMF, dimethylsulfoxide = DMSO) solutions of ammonium thiocyanate in the presence of Ten were investigated. The crystal structures of the compounds [Zn2(NCS)4(NH3)2Ten] (I), (HTen)2[Zn(NCS)4] (II) and [Zn(NCS)2(Ten)DMSO] (III) were determined by X-ray diffraction. The complexes contain four (I) and five (III) coordinate zinc atoms linked by μ2-bridging nitrogen atoms of Ten forming the dimeric and polymeric molecules respectively; the complex (II) has an ionic-type crystal lattice with (HTen)+ cations and [Zn(NCS)4]2− anions.

Synthesis and structure of diaqua-bis(ethylenediamine)copper(II) salts with anions of carbamic acids

Abstract Two complexes of diaqua-bis(ethylenediamine)copper(II) with anions of N-car☐yglycine and ethylenediaminebiscar☐ylic acid [Cu(en)2(H2O)](OOCCH2NHCOO) · H2O (1) and [Cu(en)2(H2O)2](OOCNHCH2CH2NHCOO) · 2H2O (2) were synthesized and investigated by single-crystal X-ray analysis and IR spectroscopy. Compound 1 was obtained by direct synthesis upon interaction of copper powder with glycine hydrochloride in methanol solution upon heating in air. Compound 2 was isolated as a result of a reaction between a copper(II) anionic complex with pyruvoylamide oxime (H2pox) of composition K[Cu(pox)(Hpox)] with ethylenediamine and formaldehyde in methanol solution. In both cases formation of carbamate anions is connected with uptake of atmospheric carbon dioxide by the reaction mixtures. The crystal structures of 1 and 2 comprise [Cu(en)2H2O)2]2+ cations, carbamic acids anions and solvate water molecules. The complex cations of 1 and 2 consist of two ethylenediamine molecules coordinated in the equatorial plane [Cu-N = 2.007(3)–2.024(3)A for 1 and 1.996(2) and 2.022(2)A˚ for 2], and water molecules occupying the apical positions of distorted octahedral [Cu-O = 2.591(3) and 2.741(3)A˚ for 1 and 2.556(3)A˚ for 2]. The extended hydrogen bond system in 1 and 2 unites the elements of the structures.

Direct Synthesis of Heterometallic Complexes

The idea of direct synthesis of coordination compounds – use of elemental metals or their oxides as starting material – has been developed to synthesize heterometallic compounds. The advantages of this approach in obtaining polynuclear, mixed-anion and mixed-valence coordination compounds are shown, taking complexes with aminoalcohols as examples. The preparation of heterobimetallic Cu/M (Pb, Zn, Co) complexes with aminoalcohols using zerovalent copper as a starting material is presented. The main principles for the formation of heterobimetallic complexes and the most interesting crystal structures are briefly reviewed.

A new copper(II)lead(II) heterotetranuclear complex containing 2-dimethylaminoethanol: direct synthesis and structure

Abstract The heterotetranuclear CuIIPbII complex containing 2-dimethylaminoethanol has been synthesized using copper powder and PbI2 as starting materials and characterized by X-ray crystallography. The crystal comprises dimeric centrosymmetric molecules (Cu2Pb2[(CH3)2NCH2CH201414(DMSO)2 bridged by oxygen atoms of chelated 2-dimethylaminoethoxo groups, and DMSO molecules of crystallization. The nearest copper coordination environment has a somewhat distorted square planar geometry. The coordination geometry around the Pb atom is a highly distorted octahedron. The bridging oxygen atoms arrange a strictly planar central Pb202 rhombus in the structure of the complex.

Direct synthesis and crystal structure of the polymeric thiocyanate complexes of copper(I)

Abstract The compounds Cu(SCN)·CH3CN (1) and [(CH3)3NH]+[Cu2(SCN)3]− (2) have been synthesized using a direct method of interaction and characterized by X-ray crystallography. The planar Cu2S2 units with the copper-copper distances 3.095 (1) and 2.972 A (2) form the basis of both structures. Complex 1 consists of the infinite puckered layers with the interlayer distance 6.657 A. The three-dimensional polymeric anion [Cu2(SCN)3]− in compound 2 comprises two crystallographically independent copper(I) atoms and two bridging thiocyanate groups with different coordinations.

Direct synthesis and crystal structure of a mixed-valence copper complex

Abstract The mixed-valence complex [CuII (DMF)4][Cu4I(SCN)4 (CN)2] (DMF = N,N-dimethylformamide) has been synthesized using a direct method of interaction and characterized by X-ray crystallography. The complex consists of layers formed by polymeric [Cu4I (SCN)4 (CN)2]n2− anionsand the [CuII(DMF)4]2+ cations disposed between anionic layers.

Direct synthesis and crystal structure of lead(II) iodide complex with ethanolamine

Abstract The complex Pb6(HEa)2I6, (where HEa is ethanolamine) was obtained by interaction of lead oxide powder and ammonium iodide in ethanolamine. The crystal structure of the compound was determined by X-ray crystallography. The crystal is formed by [Pb2(HEa)2(Ea)22+ and [Pb4(Ea)44+ cations and iodide anions. Bidentate aminoethoxo groups are coordinated to lead via the oxygen and nitrogen atoms, whereas monodentate aminoethanol molecules are attached through the nitrogen atoms only.

Direct synthesis and crystal structure of tetrameric copper(I) iodide with trimethylamine [CuI(NMe3)]4

Abstract The tetrameric cluster [CuI{N(CH3)3}]4 has been synthesized directly from copper powder and trimethylammonium iodide in non-aqueous solutions (acetonitrile, N,N-dimethylformamide) and characterized by X-ray crystallography. The compound [CuI{N(CH3)3}]4 possesses a molecular structure. A tetrahedral Cu4 cluster with short CuCu distances (2.67 A) is surrounded by an I4 tetrahedron, thus each face of the Cu4 tetrahedron is centred by a μ3-bridging iodine atom.

Crystal structure of chloride and iodide complexes of lead(II) with 2-dimethylaminoethanol obtained by direct synthesis

Abstract The compounds {Pb5Cl6[(CH3)2NCH2CH2O]4} and {Pb3[(CH3)2NCH2CH2]3I}I2, where (CH3)2NCH2CH2O is deprotonated 2-dimethylaminoethanol, have been synthesized using the direct method of interaction and characterized by X-ray crystallography. The 2-dimethylaminoethoxo groups have the gauche conformation and are coordinated via oxygen and nitrogen atoms. The chloride complex contains five- and eight-coordinate lead(II) atoms linked by μ3-bridging oxygen and μ2-bridging chlorine atoms, whilst in the iodide complex three- and four-coordinate metal atoms are linked by μ3- and μ2-bridging oxygen atoms. The structural differences between the coordination environments of the lead atoms are discussed in connection with the emergence of the “inert pair” effect. The compound {Pb5Cl6[(CH3)2NCH2CH2O]4} possesses molecular structure whilst {Pb3[(CH3)2NCH2CH2O]3I}I2 has an ionic-type crystal lattice.

Crystal structure of poly[{tris-μ-iodo-bis }-μ-iodo] obtained by direct methods using Lead(II) oxide as a starting material

Abstract A direct method of obtaining (Pb4I4L2)n, where L is twice deprotonated 2,2′,2″-nitrilotriethanol (triethanolamine), is reported. The crystal structure of the compound was determined by X-ray techniques. The crystallographically independent fragments of Pb4I4L2 are associated by bridging oxygen and iodine atoms in endless layers parallel to the bc-plane of the crystal. Tetradentate twice deprotonated triethanolamine is coordinated to lead(II) via oxygen and nitrogen atoms.