V. V. Kovalev

Electronic structure patterns of isoelectronic compounds

Abstract X-ray photoelectron spectra of the valence levels of AO 4 x − anions (A = P, S, Cl, As, Se), AO 3 x − anions (A = S, Cl, I, Se, Te, Br) and AF 6 x − anions (A = Al, Si, As) have been studied. The spectra are interpreted and the electronic structures are considered for the isoelectronic and isovalent compounds.

Coordination silver polymer with the bridging anion of oxadiazolylacrylic acid: Synthesis, crystal structure, and luminescence properties

Metal complex [AgL] (I) is synthesized by the reaction of AgNO3 with 3-(5-furyl-1,3,4-oxadiazol-2-yl)acrylic acid (HL, C9H6N2O4), and its crystal structure is determined (CIF file CCDC no. 1426528). The crystals are monoclinic, space group P21/n, a = 4.946(1), b = 20.084(1), c = 9.015(1) Å, β = 92.32(1)°, V = 894.482 Å3, ρcalcd = 2.442 g/cm3, Z = 4. In structure I, pairs of centrosymmetric silver atoms are bound by bidentate-bridging oxygen atoms of two anions L into dimeric blocks. The Ag–Ag distance in the dimer is 2.854(1) Å. The coordination sphere of Ag+ contains two oxygen atoms, one silver atom, and one nitrogen atom of the diazolyl fragment of the adjacent anion. The coordination polyhedron of Ag+ is a strongly distorted tetrahedron. The molecular packing of crystal I is built of infinite ribbons (AgL)n extended along the direction [001]. The photoluminescence spectrum of compound I contains intense bands about 550 nm corresponding to the green spectral range and less intense bands at 425 and 485 nm.

3D Supramolecular structure of the coordination polymer [Ag(2-MePyz)ReO4]

The complex [Ag(2-MePyz)ReO4] (I) is synthesized, and its structure is determined. The crystals are monoclinic, space group P 21/c, a = 7.234(1), b = 15.451(1), c = 8.036(3) Å, β = 92.56(1)°, V = 897.3(2) Å3, ρcalcd = 3.347 g/cm3, Z = 4. Structure I consists of cationic polymer chains [Ag(2-MePyz)]∞+. Anions ReO4− are weakly bound to Ag+ (Ag...Oaverage 2.693 Å) and join the latter into a supramolecular framework. The Ag+ ion has a linear coordination (NAgN 177.9(2)°, distances Ag-N 2.223(5) and 2.242(5) Å).

Coordination molecular compounds of cadmium(II) iodide with dimethylpyridines

The reactions of CdI2 with dimethylpyridines (Me2Py is C7H9N) afford complexes CdI2(2,3-Me2Py)2] (I), [CdI2(2,6-Me2Py) (II), and CdI2(3,5-Me2Py)2 (III). The structures of compounds I and II are determined. The crystals of complex I are orthorhombic, space group Pbca, a = 7.930(1) Å, b = 15.537(1) Å, c = 29.943(1) Å, V = 3689.1(5) Å3, ρcalcd = 2.090 g/cm3, Z = 8. The crystals of complex II are monoclinic, space group C2/c, a = 14.784(1), b = 11.991(1), c = 17.711(1) Å, β = 90.39(1)°, V = 1081.1(2) Å3, ρcalcd = 2.908 g/cm3, Z = 4. The structure of compound I is built of discrete neutral complexes [CdI2(2,3-Me2Py)2]. The Cd polyhedron is a distorted tetrahedron (Cd-I 2.289–2.295, Cd-N 2.708–2.734 Å, angles N(I)CdN(I) 103.1°-114.8°). Polymer chains [CdI2(2,6-Me2Py)]∞ extended along the direction [100] are observed due to the bridging iodine atoms in structure II. The Cd polyhedron is a trigonal bipyramid containing iodine atoms at the axial vertices (Cd-Iaks 3.040 Å) and two iodine atoms and the nitrogen atom of the Me2Py ligand in the equatorial plane Me2Py (Cd-Ieq 2.840 Å, Cd-N 2.309 Å). The compounds in the solid state are photoluminescent.

A complex of cadmium(II) iodide with 4-cyanopyridine: Synthesis, crystal structure, and luminescent properties

The complex [CdI2(4-CNPy)2] (I) was obtained by a reaction of CdI2 with 4-cyanopyridine (4-CNPy, C6H4N2) and structurally characterized (CIF file CCDC no. 983377). The crystals of complex I are monoclinic, space group C2, a = 24.698(5) Å, b = 4.127(1) Å, c = 7.597(2) Å, β = 96.05(1)°, V = 770.0(3) Å3, ρcalcd = 2.477 g/cm3, Z = 2. In structure I, iodine atoms serve to unite complex molecules into the polymer chains [CdI2(4-CNPy)2]∞ along the direction [010]. The Cd(1) atom lying on a twofold axis has a slightly distorted octahedral environment made up of four bridging iodine atoms and two nitrogen atoms of two ligands 4-CNPy (Cd-Iav, 2.947(2) and Cd-N(1), 2.410(6) Å). Within each chain, cadmium atoms are spaced apart at 4.13 Å. Complex I exhibits photoluminescence.

Structures of the silver complexes with lutidines according to the NMR data. Crystal structure of [AgNO3(3,5-Lut)2]

The silver(I) nitrate complexes with 2,3-, 2,4-, 2,6-, and 3,5-lutidine (Lut, dimethylpyridine C7H9N), [AgNO3(Lut)2], are synthesized and studied by multinuclear NMR (1H, 13C, and 15N) in various solvents (chloroform, dimethyl sulfoxide, and acetonitrile). The influence of steric and electronic factors of the organic ligand on the parameters of the NMR spectra is revealed. It is shown that the 15N NMR spectra are the most informative. The structure of complex [AgNO3(3,5-Lut)2] is determined. The crystals are monoclinic, space group C2/c, a = 14.599(1) Å, b = 8.422(1) Å, c = 12.954(1) Å, β = 99.60(1)°, V = 1570(2) Å3, ρcalcd = 1.625 g/cm3, Z = 4. The structure is built of discrete neutral complexes [AgNO3(3,5-Lut)2]. The coordination mode of the Ag+ ion includes two nitrogen atoms of two crystallographically equivalent lutidine ligands (Ag-N 2.194(5) Å, angle NAgN 147.6(3)°). The nitrate ion behaves as a weak chelating ligand with respect to the Ag+ ion (Ag…O 2.674(6) Å).

Silver complexes with 2-amino-4-methylpyrimidine: Synthesis, crystal structure, and luminescent properties

Reactions of AgReO4 and AgCH3SO3 with L = 2-amino-4-methylpyrimidine (Ampym, C5H7N3) in a ratio of 1: 2 in acetonitrile gave the complexes [AgL2(ReO4)] (I) and [AgL2(CH3SO3)] (II). Their structures were determined. The crystals of complex I are monoclinic, space group C2/c, a = 5.985(1), b = 3.465(1), c = 19.071(1) Å, β = 96.52(1)°, V = 1527.0(3) Å3, ρcalcd = 2.507 g/cm3, Z = 4. The crystals of complex II are orthorhombic, space group Pbca, a = 14.784(1), b = 11.991(1), c = 17.711(1) Å, V = 3139.7(4) Å3, ρcalcd= 1.782 g/cm3, Z = 8. Structure I shows discrete cationic complexes [AgL2]+. The silver atom is virtually linearly coordinated to two N atoms of crystallographically equivalent ligands L (Ag-N, 2.156(4) Å; the angle NAgN, 174.7(4)°). The complex cations are united into zigzag chains through the hydrogen bonds N-H...N. The resulting chains are linked by the hydrogen bonds N-H...O to uncoordinated perrhenate anions to form 2D supramolecular layers. In structure II, the Ag+ ion is coordinated by two crystallographically non-equivalent ligands L in a distorted linear fashion: Ag(1)-N(1), 2.166(7) Å;Ag(1)-N(4), 2.181(6) Å; the angle NAgN, 157.2(2)°. The anions CH3SO3− are weakly linked to the Ag+ ions (Ag...O 2.72 Å) and are hydrogen-bonded to the complex cations [AgL2]+, uniting them into supramolecular ribbons.

Synthesis and structure of silver coordination polymer with extended ditopic ligand containing terminal amino groups [Ag(C24H28N2)1.5]NO3

Abstract[AgL]NO3 and [AgL1.5]NO3 (I) complexes, where L = NH2-C6H4-C(CH3)2-C6H4-C(CH3)2-C6H4-NH2, were obtained. The structure of compound I was determined. Triclinic crystals, space group P

Synthesis and crystal structure of the mixed-ligand coordination silver polymer [Ag(CH3SO3)(2,3-Et2Pyz)] · H2O

\bar 1

Layered structure of the silver coordination polymer with nonrigid aromatic diamine {Ag[CH2(C6H4NH2)2]2(CH3C6H4NH2)}NO3

, a = 6.259(1) Å, b = 15.663(1) Å, c = 20.653(3) Å, α = 71.13(1)°, β = 81.66(1)°, γ = 82.45(1)°, V = 1887.8(3) Å3, ρcalc = 1.208 g/cm3, Z = 2. Ag+ ion coordinated to three nitrogen atoms of ligands L has a distorted T-shaped coordination. The structure of I is built of cationic polymeric chains [Ag(L)]∞+ composed of one bridging ligand L (Ag-N(l) = 2.207(6) Å and Ag-N(2) = 2.221(6) Å, NAgN angle is 160.5(2)°). Second crystallographically nonequivalent centrosymmetrical ligand L pairwise combines the chains to form infinite tapes along direction [010] (Ag(l)-N(3) = 2.529(6)Å). Noncoordinated NO3− anion (Ag(1)…O(1) = 2.982(6) Å) participates in N-H…O hydrogen bonds as proton acceptor to form 3D supramolecular assembly.