Crystal structure and EPR spectra of glycilglycilglycinocopper(II)bromide sesquihydrate

The title compound, Cu(glyglygly)Br·1·5H₂O, crystallizes in the space group C2/c, with a = 21.468(7), b = 6.716(5), c = 16.166(6) Å, = 98.39°, and Z = 8. The tripeptide is bonded to one Cu(II) ion through the nitrogen [Cu–N=1.97(1)Å] and oxygen [Cu–O=2.019(8)Å] atoms of the amino end glycine residue and to another Cu(II) through one oxygen atom [Cu–O=1.931(9)Å] of the terminal carboxyl group. This give rise to covalently bonded and infinite ···–Cu–tripeptide–Cu–··· chains. These chains are linked to one another by a network of H-bonds involving the water molecules and bromide ions. The Cu(II) ion is in a distorted tetragonal pyramidal coordination polyhedron. At the corner of the base of the pyramid are the terminal glycine nitrogen and oxygen atoms of one tripeptide, a carboxylic oxygen of another tripeptide and a bromide ion. The fivefold coordination is completed with a water molecule at the top of the pyramid [Cu–Ow=2.286(9)Å]. For all orientations of the applied magnetic field the single crystal EPR spectra display a single anisotropic exchange collapsed resonance without hyperfine structure. Its position was measured in three perpendicular planes and the crystal g-tensor evaluated from the data. This tensor is interpreted in terms of the contributing Cu(II) complexes in the unit cell to deduce the principal values g₁ = 2.273, g₂ = 2.050 and g₃ = 2.131 for the molecular gyromagnetic tensor. We also discuss the magnitude of the exchange interaction between neighboring copper ions in the lattice on the basis of the features in the EPR spectra and the structural information.     

EPR spectra of (L-aspartate)di(2-pyridyl)aminezinc(II) hydrate substitutionally copper(II) doped complex

The [(L-aspartate)di(2-pyridyl)aminezinc(II)]hydrate doped with traces of copper was prepared. Electron paramagnetic resonance spectra of the polycrystalline sample were recorded at room temperature by using the X-band of the EPR spectrometer. The observedg factors for the complex areg _‖=2.258 andg _⊥=2.066. TheA _‖ value is 165.10⁻⁴ cm⁻¹. The crystal and molecular structure of the complex are also reported. The complex crystallizes in the monoclinic system; space groupP2₁ witha=7.2053(11),b=10.447(2),c=10.812(2) Å, β=108.489(14)° andZ=2. The structure can be described in the crystal lattice as polymeric chains.     

EPR spectra of (L-aspartate)di(2-pyridyl)aminezinc(II) hydrate substitutionally copper(II) doped complex

The [(L-aspartate)di(2-pyridyl)aminezinc(II)]hydrate doped with traces of copper was prepared. Electron paramagnetic resonance spectra of the polycrystalline sample were recorded at room temperature by using the X-band of the EPR spectrometer. The observedg factors for the complex areg _‖=2.258 andg _⊥=2.066. TheA _‖ value is 165.10⁻⁴ cm⁻¹. The crystal and molecular structure of the complex are also reported. The complex crystallizes in the monoclinic system; space groupP2₁ witha=7.2053(11),b=10.447(2),c=10.812(2) Å, β=108.489(14)° andZ=2. The structure can be described in the crystal lattice as polymeric chains.     

X-ray structure of {[μ-N,N′-Bis(salicylidene)-1, 3-propane-diamine] (dimethylformamide) zinc(II)} dibromo cadmium(ii)

The title compound, forms crystals which are the orthorhombic system, space group P2 ₁2₁2₁, with unit cell dimensions a = 10.3928(12) Å, b = 14.6298(13) Å, c = 15.9514(11) Å, V = 2425.3(4) ų. The cell contains four molecules. The structure is a heteronuclear dimeric complex with Zn^II and Cd^II ions. The coordination around the Zn^II ion is distorted square–pyramid and the Cd^II ion is distorted tetrahedral coordination. The Zn·sCd distance is 3.3594(7) Å.     

The structure and EPR properties of (CH2OHCH2NH3)2CuCl4

The title compound is a member of the (RNH₃)₂CuCl₄ layer perovskite family, space group C2/c, witha=21.624(5),b=7.511(1),c=7.431(2)Å, =89.56(2)° andV=1206.9(4)ų withZ=4. In the antiferrodistortive structure, the Cu(II) ion assumes an elongated octahedral coordination (unique Cu–Cl distances=2.274(2), 2.288(2), and 3.010(2)Å). The octahedra share corners with four neighbors to form a two-dimensional network. The –NH₃ moieties hydrogen bond to the layers, so that the –C₂H₅OH moieties form sheathes about each metal halide layer. A twofold disorder of the –C₂H₅OH groups is observed. The EPR spectrum is investigated to help understand the magnetic properties of the systems. Theg-values are consistent with strong intralayer exchange coupling. The EPR linewidths show evidence of spin diffusion effects at liquid nitrogen temperature. However, at room temperature, the spin anisotropies lead to broadening of the EPR lines through a phonon modulation mechanism.     

Synthesis,crystal and molecular structure of trans‐bis(2‐pyridinepropanol)bis(saccharinato)nickel(II)

Trans‐bis(2‐pyridinepropanol)bis(saccharinato)nickel(II), [Ni(sac)₂(pypr)₂], where sac and pypr are the saccharinate anion and the 2‐pyridinepropanol molecule, respectively, crystallizes in the triclinic space group P (No. 2) with a = 8.1981(8), b = 9.9680(10), c = 10.4956(10) Å, α = 90.740(3)° β = 108.142(3)°, γ = 111.025(3)°, Z = 1, V = 1.537 ų. The structure of the nickel(II) complex consists of neutral molecules in which the nickel(II) ion sits on a center of symmetry and is octahedrally coordinated by two sac ligands, and two neutral pypr ligands. The pypr acts as a bidentate N‐ and O‐donor ligand forming a seven‐membered chelate ring, while sac behaves as a monodentate O‐donor ligand via the carbonyl O atom. The Ni‐N bond distance is 2.1016(15) Å, whereas the Ni‐O_pypr and Ni‐O_sac bond distances are 2.1280(12) and 2.0792(11) Å, respectively. The individual molecules are held together with a strong hydrogen bond between the hydroxyl O atom of pypr and N atom of sac and the C‐H…O type weak hydrogen bonds between some ring hydrogen atoms of pypr and sac, and the carbonyl and sulfonyl O atoms of sac in the neighbouring molecules. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Self‐assembly of a cadmium(II) diamondoid net with 2‐fold interpenetrating microporous structure

Assembly of 5‐methoxyisophthalic acid (H₂moip) with cadmium(II) ions in the presence of neutral ancillary 1,3‐bis(4‐pyridyl)propane (bpp) yields a new coordination polymer, [Cd(moip)(bpp)(H₂O)]_n·nH₂O ( 1 ). X‐ray single‐crystal diffraction determination reveals that complex 1 crystallizes in the space group C2/c of monoclinic crystal system: a = 14.545(2), b = 18.749(3), c = 17.359(3) Å, β = 105.480(2)º. Complex 1 is a 4‐connected 3D diamondoid topological framework with a 2‐fold interpenetration. Interestingly, the dense adamantine cages with inherent microporous structure are filled with free water molecules to further stabilize the coordination network.     

Single crystal EPR study of Mn(II) doped MgRb2(SO4)2·6H2O: A case of interstitial site

Single crystal electron paramagnetic resonance studies on magnesium rubidium sulphate hexahydrate doped with Mn(II) impurity, in the form of 0.1% of manganous chloride, are carried out at room temperature. The angular variation spectra of the crystal in the three orthogonal planes show that the paramagnetic impurity Mn(II) has entered the host lattice interstitially. The spin Hamiltonian parameters calculated are: g_xx = 1.974, g_yy = 1.928, g_zz = 1.980; A_xx = 9.28, A_yy = 8.58, A_zz = 9.87 mT and D_xx = ‐18.71, D_yy = ‐5.59, D_zz = 24.30 mT. The room temperature and liquid nitrogen temperature study for polycrystalline sample indicate no phase transition. The percentage covalency of Mn–O bond has been estimated to be 11. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Influence of Host Lattice in Interstital Dopant Sites: EPR Studies on Cu (II) Doped Sarcosine Cadmium Bromide Single Crystals

EPR study of Cu(II) doped in sarcosine cadmium bromide single crystals are carried out at room temperature. The impurity ions occupy the interstitial position in this crystal lattice. Crystalline field around the Cu(II) ion in this low symmetry crystal is rhombic. The transitions arise from a single paramagnetic site with g_xx = 2.1082, g_yy = 2.0005, g_zz = 2.2071, and A_xx = ‐64 x 10^‐4 cm^‐1, A_yy = ‐23 x 10^‐4 cm^‐1, A_zz =‐185 x 10^‐4 cm^‐1. The ground state is an admixture of dx2‐y2 and dz2 states. The observed molecular orbital coefficient value a2 = 0.85 reveals a moderate covalency of the s bonding and b2 = 0.967 indicates the weak pi bonding. A strong interaction between Cu(II) and nitrogen ligands is found to exist.     

Solid-phase synthesis, crystal structure, and quantum chemical calculation of a molybdenum(II) complex with bis(diethyldithiocarbamate)

The complex Mo(Et₂dtc)₂ [Et₂dtc: bis(diethyldithiocarbamate)] was synthesized by solid-phase reaction at room temperature and characterized by elemental analysis, powder XRD, IR, ¹H NMR and TG/DTA. Its crystal structure was determined by X-ray single crystal diffraction. The crystals are monoclinic with space group P2₁/c, a=0.61800(12) nm; b=1.1540(2) nm; c=1.1610(2) nm; β=95.78(3)°; V=0.8238(3) nm³; D _c=1.582 g/cm³; Z=2 F(000)=400; μ=1.285 mm⁻¹; R=0.0703; wR=0.2330; GOF=1.060. The coordination geometry of Mo atom, by four S anions from Et₂dtc ligand, is that of a slightly distorted planar square. Furthermore, the optimized geometry, charge distribution, and thermodynamic functions were calculated by quantum chemical method.     

Synthesis,characterization and X‐ray crystal structure of guanidinuim (pyridine‐2,6‐dicarboxylato)(pyridine‐2,6‐monocarboxylato) zincate(II) mono pyridine‐2,6‐dicarboxylic acid tetrahydrate

A new complex of Zinc(II) and guanidinium pyridine–2,6–dicarboxylate proton transfer compound, (GnH)₂ (pydc), was synthesized and characterized using IR, ¹H NMR and ¹³C NMR spectroscopy and single crystal X–ray diffraction. The chemical formula and space group of the resulting complex is (GnH)[Zn(pydc)(pydcH)] · (pydcH₂) · 4H₂O, P 1 where the final R value is 0.0310 for 13287 reflections collected. The [Zn(pydc)(pydcH)]^– anions and the (GnH)⁺ counter‐cations form a three‐dimensional solid‐state structure by a variety of noncovalent interactions such as ion pairing, hydrogen bonding and π–π stacking which are going to be discussed. (© 2007 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structure of bis(dipropyldithiocarbamate) cadmium(II), [Cd2(n-Pr2dtc)4] (dtc = dithiocarbamate)

The cadmium complex of bis(dipropyldithiocarbamate), [Cd₂(n-Pr₂dtc)₄] (dtc = dithiocarbamate) was crystallized from ethylether. It crystallizes in the monoclinic system, space group P _2I/c, with lattice parameters, a = 8.2532(1), b = 19.4519(1), c = 13.4163(2) Å, = 99.243(1)°, and Z = 4. The X-ray single-crystal structure of [Cd₂(n-Pr₂dtc)₄] reveals that the complex is binuclear in the solid state and the Cd atom has a distorted square-pyramidal coordination environment and four equatorial donors are the two bidentate chelate sulfur atoms from two dtc ligands, of which the sulfur atom from the bridging dtc ligand occupies the apical position of the symmetry-related Cd atom in the dimer structure.     

Synthesis and X‐ray structure of two conformational isomers of [Zn(medpt)(SCN)2], medpt = bis (3 – aminopropyl)methylamine

Two conformational isomers of [Zn (medpt)(NCS)₂], medpt=bis(3‐aminopropyl) methylamine, (1) and (2) have been synthesised and the crystal structures are determined using single crystal X‐ray diffraction. The structures of the complexes have been solved by Patterson method and refined by full‐matrix least‐ squares techniques to R1 = 0.0524 for (1) and R1 = 0.0506 for (2), respectively. The geometry around the Zn(II) centre in both isomers is distorted trigonal bipyramidal. The two pendent thiocyanate moieties in (1), with Zn–N–C angles 167.9(4)–173.9(4)º, coordinate the mental centre almost linearly while the corresponding coordinations in (2) are significantly bent [Zn–N–C angles 150.8(3)–153.1(2)°]. Intermolecular N–H…S hydrogen bonds stabilise the crystal packing in the complexes forming infinite chains parallel to the [100] direction. The combinations of molecular chains generate three/two dimensional supramolecular framework in complexes (1) and (2). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and structural characterization of 2-mercapto-1-tert-butylimidazole and its Group 12 metal derivatives (HmimtBu)2MBr2 (M = Zn, Cd, Hg)

2-Mercapto-1-tert-butylimidazole (Hmim^tBu) and its Group 12 metal complexes (Hmim^tBu)₂ MBr₂ (M = Zn, Cd, Hg) have been readily prepared and structurally characterized. Whereas the former displays a dimeric structure in the solid state with two S H–N interactions linking each pair of molecules, the four-coordinate complexes exhibit distorted tetrahedral geometries with the S–M–S angles in the range 103.2–135.2. The average M–Br bond lengths are 2.401, 2.567, and 2.688 Å for M = Zn, Cd, and Hg, respectively, and the corresponding average M–S bond distances are 2.350, 2.540, and 2.467 Å. The average C–S bond length for all the complexes (1.72 Å) is only ca. 0.02 Å longer than the corresponding value in the free ligand. Hmim^tBu is orthorhombic, space group Pbca, a = 10.1571(5) Å, b = 9.7906(5) Å, c = 17.6616(9) Å, V = 1756.34(15) ų, Z = 8; (Hmim^tBu)₂ZnBr₂ is monoclinic, space group C2/c, a = 17.187(3) Å, b = 8.9908(17) Å, c = 15.560(3) Å, = 117.206(3), V = 2138.3(7) ų, Z = 4; (Hmim^tBu)₂CdBr₂ is triclinic, space group P , a = 7.4625(6) Å, b = 9.6149(9) Å, c = 31.020(3) Å, = 93.485(2), = 94.579(2), = 103.872(2), V = 2146.6(3) ų, Z = 4; (Hmim^tBu)₂HgBr₂ is monoclinic, space group P2₁/c, a = 6.8908(6) Å, b = 10.2397(9) Å, c = 29.859(3) Å, = 94.364(2), V = 2100.7(3) ų, Z = 4.     

Crystal structure and EPR spectrum of dimeric di-μ-azide-bis[cyanide(N,N-diethylethylenediamine)]-copper(II), [Cu(N3)(NCO)(diEten)]2

The title compound, [Cu(N₃)(NCO)(C₆H₁₆N₂)]₂, crystallizes in the space groupP2₁/n, witha=8.336(1),b=17.405(3),c=8.376(1) Å, β=109.73(2)^o andZ=4. The molecules are arranged as centrosymmetric dimers in which two azide ligands bridge neighboring copper ions in an asymmetric head-on fashion. The Cu(II) ion is coordinated to five nitrogen atoms which form a distorted tetragonal pyramid. At the pyramid base are the two N atoms of a diEten molecule [Cu−N=2.00(1), 2.130(9) Å], an azide end atom [Cu−N=1.99(1) Å] and a NCO group [Cu−N=1.93(1) Å]. At the pyramid apex is the other, inversion related, azide N atom in the dimer [Cu−N=2.38(1) Å]. This Cu−N contact links the monomers within a dimer. Neighboring dimers are coupled by weak N−H…O contacts. Single crystal EPR data at X-band show that the pair of resonances expected for neighboring, magnetically nonequivalents dimers, collapse into a single line, a signature of inter-dimers superexchange coupling. The observed crystal gyromagnetic tensor is used to disclose the electronic and magnetic structure around Cu(II) ions.     

X-ray crystal structure oftrans-dinitratotetrapyridinezinc(II)-pyridine solvate,a clathrate compound

The X-ray structure oftrans-dinitratotetrapyridinezinc(II)·2 pyridine has been determined. Clear colorless crystals of the complex crystallize in the orthorhombic space group Ccca, with cell dimensionsa=12.108(3),b=14.966(7) andc=17.113(4)Å;V=3101.0(18)ų and Z=4. Unique reflections, 755, withI _net>3 (I) on refinement afforded values ofR=0.069 andR _w=0.075.     

Crystal and molecular structure of bis(N,N-diethyldithiocarbamato)palladium(II)

The crystal and molecular structure of bis(N,N-diethyldithiocarbamato)palladium(II), Pd(S₂CN(C₂H₅)₂)₂, has been determined by a three-dimensional X-ray analysis. The compound crystallizes in the tetragonal space groupP4₂/n with unit cell dimensionsa = 16·439(8) Å andc = 6·247(3) Å. The crystals are isomorphous with bis(N,N-diethyldithiocarbamato)platinum(II). Intensities were obtained with an automatic diffractometer. The structural parameters were refined by least-squares methods to a conventionalR factor of 0·038 for 600 non-zero observed reflections. The palladium is in planar coordination with four sulphur atoms, the two non-equivalent Pd-S bond lengths being 2·317(3) and 2·315(3) Å.The authors are grateful to Mr J. G. M. van Rens for providing the crystals and measuring the unit cell dimensions, to Professor J.J. Steggerda for his continuous interest and to Mr W.P.J.H. Bosman, Mr J.M.M. Smits and Mr J.A.B.C. Wolf for valuable assistance.     

Crystal and molecular structure of chloro(tri-t-butylphosphino-C,P)triphenylarsinepalladium(II)

(SP-4-4)-chloro[2-(di-tert-butylphosphino)-2-methylpropyl-C,P] (triphenylarsine)palladium(II), C₃₀H₄₁ClPAsPd, has been characterized by single-crystal X-ray diffraction data. It crystallizes in the monoclinic space groupP2₁ witha=9.611(2),b=14.335(2),C=11.953(1) Å,=111.97(1)° andZ=2. The phasing model was determined by direct methods and the full-matrix least-squares refinement of 302 structural parameters yielded a reliability factor of 0.039 for 2269 unique reflections withI> 3(I). The square planar geometry about the Pd atom is angularly distorted due to the steric bulk of the ligands and the formation of the four-membered ring, Pd-P-C(2)-C(1), which is severely distorted. The arsine and phosphine ligands are orientedtrans across the square-planar geometry with an As-Pd-P angle of 163.5(1)°. Details of the structural content and selected bond lengths and angles are discussed. The phenyl rings are planar and in a staggered orientation. Steric bulk illustrations from ligand profile calculations (/2 vs ) about the arsine and phosphine ligands are presented.     

Growth and properties of an organometallic nonlinear optical crystal: bis(isothiocyanato)‐bis(4‐methylpyridine)zinc(II) (Zn(SCN)2(C6H7N)2)

Bis(isothiocyanato)‐bis(4‐methylpyridine)zinc(II)(Zn(SCN)₂(C₆H₇N)₂), (abbreviated as ZBNC) single crystals of optical quality have been grown from acetone solution by the slow temperature‐lowering method. Its solubilities at different temperatures in acetone were measured. The X‐ray powder diffraction (XRPD) spectroscopy of ZBNC crystal was performed at room temperature. The second harmonic generation (SHG) efficiency was determined by powder technique of Kurtz and Perry using Nd:YAG laser, which is equivalent to KDP crystal. The thermal decomposition process was characterized by thermal gravity and differential thermal analysis (TG\DTA). The specific heat of the crystal is 1440.67 J/mol·K at 325 K. The IR spectrum was recorded in the 500∼3500 cm^–1 region, using KBr pellets on a Nicolet 170sx FT‐IR spectrometer. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,characterization and crystal structure of a 2D Cd(II) complex with a 4,4'‐diazenediyldiphthalic acid ligand

An exploration of the cadmium‐L system under hydrothermal condition, has led to the isolation of a novel framework {[Cd(L)_0.5(H₂O)₃]}_n ( 1 ) (H₄L = 4,4'‐diazenediyldiphthalic acid). Single‐crystal X‐ray analysis reveals that it crystallizes in the triclinic space group P‐1. a = 5.746(3) Å, b =6.526(4) Å, c = 14.701(8) Å, α=92.348(8), β = 99.622(6), γ=106.877(7)°. The Cd^II ions are linked into an extended 2‐D rectangle‐like structure via L ligands, which exhibits an attractive three‐connected honeycomb topological network. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)