The monoclinic polymorph of rac‐5,7,7,12,12,14‐hexa­methyl‐1,4,8,11‐tetraazonia­cyclo­tetra­decane bis­(hexa­fluoro­germanate) tetrahydrate

X‐ray data were obtained for the monoclinic polymorph of rac‐5,7,7,12,12,14‐hexa­methyl‐1,4,8,11‐tetraazonia­cyclo­tetra­decane bis­(hexa­fluoro­germanate) tetrahydrate, (C₁₆H₄₀N₄)[GeF₆]₂·4H₂O. The tetra­aza‐macrocyclic cations lie across inversion centers in space group P2₁/c. Water mol­ecules and [GeF₆]²⁻ anions form zigzag chains, which alternate in a three‐dimensional network with the macrocyclic cations. The structure is sustained by multiple hydrogen bonds.     

X‐Ray Photoelectron Spectral Studies on Planar NiS4 and NiS2P2 Chromophores. Single Crystal X‐Ray Structural Study on [1, 4‐Bis(diphenylphosphino‐k,P, P')butane](piperidinecarbodithioato‐S,S')‐Nickel(II) Perchlorate

X‐ray photoelectron spectral study was made on the complexes Ni(nmedtc)₂( 1 ), [Ni(nmedtc)(PPh₃)₂]ClO₄( 2 ), [Ni‐(nmedtc)(dppe)]BPh₄( 3 ) (where nmedtc = N‐methyl, N‐ethanoldithiocarbamate, dppe = 1, 2‐bis(diphenylphosphino)ethane). The nickel 2p_3/2 binding energy values for chelated and free phosphine complexes are 854.0 and 854.1 eV which are significantly different from Ni2p_3/2 BE value of NiS₄ chromophore, indicating the relative dearth of electron density on Ni in NiS₂P₂ chromophores. The presence of two phosphine groups in NiS₂P₂ chromophore alleviates the electron density on the metal atom. More electron density is being pulled away from the metal atom in chelates than in the PPh₃ analogue. This observation is in line with solution studies by cyclic voltammetry. A one‐electron reduction potential was observed to be the minimum for NiS₂P₂ chromophores compared to the others. Also the crystal structure of the complex [Ni(pipdtc)(1, 4‐dppb)]ClO₄ (pipdtc^‐ = piperidinecarbodithioato anion, 1, 4‐dppb = bis(diphenylphosphino)butane) prepared by the reaction between Ni(pipdtc)₂, NiCl₂�6₂2O, and 1, 4‐dppb in CH₃CN‐CH₃OH is reported.     

XPS,single crystal X-ray diffraction and cyclic voltammetric studies on 1,10-phenanthroline and 2,2′-bipyridine adducts of bis(piperidinecarbodithioato-S,S′)cadmium(II) with CdS4N2 environment – A stereochemical and electronic distribution investigation

(1,10-Phenanthroline)bis(piperidinecarbodithioato-S,S^′)cadmium(II), [Cd(pipdtc)₂(1,10-phen)] (1) and (2,2′-bipyridine)bis(piperidinecarbodithioato-S,S′)cadmium(II), [Cd(pipdtc)₂(bipy)] (2) adducts were prepared and the crystal structures are reported. Cd–S and Cd–N distances and the angles subtended at cadmium are almost the same in both complexes but the Cd–S distances in the adducts are longer than those in Cd(pipdtc)₂ (3) complexes due to the presence of an additional neutral ligand. Thioureide C–N distance in 1 and 2 are supported by νC–N bands observed at 1471 and 1470 cm⁻¹, respectively. S2p binding energies for the adducts show a significant reduction in value compared to the parent dithiocarbamate indicating the weakening of the Cd–S bond on adduct formation. The observed reduction in binding energy is due to the increased electron density on the metal in the adducts. The cyclic voltammetric study on the complexes also show an increase of electron density on cadmium in the adducts compared to Cd(pipdtc)₂.     

Coordination compounds of cobalt,nickel, copper,and zinc with 2-bromo-3-phenylpropenal benzoylhydrazone and thiosemicarbazone

By X-ray structural analysis the crystal structure of 2-bromo-3-phenylpropenal benzoylhydrazone (HL) was determined. The molecule is not flat. In the crystal the HL molecules form infinite chains with reciprocal van der Waals interaction. 2-Bromo-3-phenylpropenal hydrazone (HL) and thiosemicarbazone (HL′) react with cobalt, nickel, copper and zinc chlorides, nitrates and acetates to form coordination compounds of the composition Cu(HL)(L)₂ [HL = C₆H₅-CH=CBr-CH=N-NH-C(O)-C₆H₅], MX₂·2 HL′·nH₂O [M = Co, Ni, Cu, Zn; X = Cl, NO₃, HL′ = C₆H₅-CH=CBr-CH=N-NH-C(S)-NH₂; n = 0–3], MX₂·HL·n H₂O [M = Ni, Cu; n = 0, 1], and ML′₂·nH₂O [M = Co, Ni, Zn; n = 0–3]. The same reactions in the presence of amines (A = C₅H₅N, 2-CH₃C₅H₄N, 3-CH₃C₅H₄N, 4-CH₃C₅H₄N) afford complexes of the composition CuALCl and MALX·n H₂O [M = Cu, Ni; X = Cl, NO₃; n = 0–2]. Structure of the coordination node in the amine-containing copper derivatives is polynuclear, in complexes Cu(HL)(L)₂ is octahedral, in other compounds it is tetrahedral. The azomethines (HL and HL′) in these complexes behave as bidentate N,O and N,S ligands. Thermolysis of the complexes includes a step of dehydration (60–90°C) and complete thermal decomposition (430–590°C).     

Crystal structures of 3-phenylpropenal thiosemicarbazone and its nickel and zinc chelates

3-Phenylpropenal thiosemicarbazone hydrate C₆H₅-HC=CH-CH=N-NH-C(S)-NH₂ · H₂O (HL · H₂O, I) and two chelates [Ni(L)₂] · nCH₃OH (II) and [Zn(L)₂] (III) are studied by X-ray diffraction. The crystals of I are orthorhombic: a = 6.227(1) Å, b = 7.763(2) Å, c = 25.585(5) Å, β = 90°, space group P2₁2₁2₁, Z = 4, R = 0.0426. A nonplanar molecule of I has an E conformation. The crystals of II are triclinic: a = 6.551(2) Å, b = 10.752(3) Å, c = 10.885(3) Å, α = 64.751(5)°, β = 82.753(5)°, γ = 89.857(5)°, space group, Z = 1, R = 0.0661. In a centrosymmetric molecule of II, the central atom coordinates two deprotonated ligands L through the immine nitrogen atom and thioamide sulfur atom at the vertices of a distorted square. The crystals of III are monoclinic: a = 25.342(2) Å, b = 9.150(2) Å, c = 21.340(3) Å, α = 90°, β = 111.84(2)°, γ = 90°, space group C2/c, Z = 8, R = 0.0556. In a molecule of complex III, two deprotonated bidentate ligands L are coordinated by the zinc ion through the immine nitrogen atoms and thioamide sulfur atoms to form a distorted tetrahedron at the central atom. In both II and III, ligand L after coordination by the metal ion changes the E conformation with respect to the N(1)-C(2) bond for the Z conformation. In crystals I-III, molecules are packed to form infinite layers parallel to the planes (001) and (010).     

Oleana‐12(13),15(16)‐diene‐3α,28‐diyl di­acetate

The title compound, C₃₄H₅₂O₄, consists of five six‐membered rings. Barring the two rings, with double bonds, all other rings are in chair conformations. Mean‐plane and ring‐puckering calculations indicate these two rings to be in distorted‐chair conformations, with distortion towards the boat conformation. There are no strong hydrogen bonds and the structure is stabilized by van der Waals interactions only. The structure is compared with those reported for other triterpenes.     

Crystal structures of salicylideneguanylhydrazinium chloride and its copper(II) and cobalt(III) chloride complexes

The crystal structures of salicylideneguanylhydrazinium chloride hydrate hemiethanol solvate (I), salicylideneguanylhydrazinium trichloroaquacuprate(II) (II), and bis(salicylideneguanylhydrazino)cobalt(III) chloride trihydrate (III) are determined using X-ray diffraction. The structures of compounds I, II, and III are solved by direct methods and refined using the least-squares procedure in the anisotropic approximation for the non-hydrogen atoms to the final factors R = 0.0597, 0.0212, and 0.0283, respectively. In the structure of compound I, the monoprotonated molecules and chlorine ions linked by hydrogen bonds form layers aligned parallel to the (010) plane. In the structure of compound II, the salicylaldehyde guanylhydrazone cations and polymer chains consisting of trichloroaquacuprate(II) anions are joined by an extended three-dimensional network of hydrogen bonds. In the structure of compound III, the [Co(LH)₂]⁺ cations, chloride ions, and molecules of crystallization water are linked together by a similar network.     

Crystal structures of 6-[(2-hydroxy-1,1-bishydroxymethylethylamino)methylene]-2,4-dinitrocyclohexa-2,4-dienone hydrate and complexes of copper(II) chloride and copper(II) nitrate with this ligand

The crystal structures of 6-[(2-hydroxy-1,1-bishydroxymethylethylamino)methylene]-2,4-dinitrocyclohexa-2,4-dienone hydrate L · H₂O (I), chloro-(2-hydroxymethyl-2-methylpropane-1,3-diol-2-iminomethyl-4,6-dinitrophenolo)aquacopper hydrate [Cu(H₂O)(L-H)Cl] · H₂O (II), and (2-hydroxymethyl-2-methylpropane-1,3-diol-2-iminomethyl-4,6-dinitrophenolo)aquacopper nitrate [Cu(H₂O)(L-H)]NO₃ (III) are determined using X-ray diffraction. It is established that the salicylidene fragment of azomethine L in the structure of compound I is in a quinoid tautomeric form. In the crystal, molecules L and water molecules are joined together by hydrogen bonds into two-dimensional layers aligned parallel to the (010) plane. The copper atom in the structure of compound II coordinates the singly deprotonated tridentate molecule L (whose salicylidene fragment is in a benzenoid form), the chlorine ion, and the water molecule. The coordination polyhedron of the central copper atom is a distorted tetragonal pyramid. In the structure of compound III, the polymer chains are formed through the coordination bonds of the copper atom with two oxygen atoms of the amino alcohol fragment of azomethine L of the neighboring complex, which is related to the initial complex by the translation along the x axis. The coordination polyhedron of the central atom is an elongated tetragonal bipyramid. Polymers and nitro groups form a three-dimensional framework through hydrogen bonds.     

X-ray diffraction study of the bonding between sulphur and the elements of group IVB. The crystal and molecular structures of methylthiotriphenyl-methane, -silicon, -germanium, -tin and -lead

The X-ray analyses of the compounds methylthiotriphenyl-methane, -silicon, -germanium, -tin, and -lead were undertaken to see if the electronic interactions which affect the X-S bond could influence the molecular geometries. The five structures were solved or by direct methods or by Patterson and Fourier techniques and refined anisotropically to R = 0.053, 0.036, 0.031, 0.041, and 0.070 respectively. The central atom exhibits a distorted tetrahedral coordination; only the propeller shape orientation of the phenyl rings seems to be determined by differences in the electronic nature of the central atoms as well as by steric effects.