X-RAY STRUCTURES OF BIS[(2-AMINOPHENYL)DIPHENYLPHOSPHINE]BIS-(ETHANOL)SILVER(I) NITRATE AND TRIS[(2-AMINOPHENYL)DIPHENYLPHOSPHINE] SILVER(I) NITRATE MONOHYDRATE

Abstract

The crystal structures of two Ag(I) salts, [Ag(LH)₂(EtOH)₂](NO₃) (1) and [Ag(LH)₃](NO₃).H₂O (2) where LH is (2-aminophenyl)diphenylphosphine, have been determined at room temperature. In 1 the Ag atom is coordinated by two P atoms derived from the phosphine ligands (Ag-P(1) 2.433(3) and Ag-P(2) 2.439(3) Å and P(1)-Ag-P(2) 160.1(1)°) and two O atoms derived from two weakly coordinating ethanol molecules (Ag-O(1a) 2.49(1) and Ag-O(2a) 2.75(1) Å). In 2 the three phosphine ligands coordinate via the P atoms (Ag-P 2.455(2), 2.462(2) and 2.484(2) Å) which define a trigonal planar geometry about the Ag atom. In neither case was any evidence found for a bonding interaction between the amino-N atom and the Ag atom. Crystals of 1 are monoclinic, space group P2₁/n with unit cell dimensions: a=10.272(4), b=16.358(2), c=23.709(3) Å, β=101.01(2)° and Z=4 and crystals of 2 are triclinic, space group P 1 with a=11.857(2), b=21.285(2), c=11.190(4) Å, α=91.77(1), β=104.50(2), γ=97.93(1)° and Z=2. The structures were each refined by a full-matrix least-squares procedure to final R=0.058 using 2433 reflections for 1 and to R=0.069 using 4428 reflections for 2.     

Crystal and Molecular Structure of Bis(1-Vinylimidazole)diacetatozinc

The crystal and molecular structure of bis(1-vinylimidazole)diacetatozinc (C₁₄H₁₈N₄O₄Zn), a highly effective antidote and antihypoxic drug, was determined [R₁ 0.0335 for 8902 unique reflections with I > 2σ(I) and wR₂ 0.0931 for all 10 752 unique reflections]. The triclinic unit cell contains two independent molecules of the complex, A and B. These molecules have short contacts O?H-C. The zinc atoms in molecules A and B have distorted tetrahedral coordination with the coordination sites occupied by the imidazole nitrogen atoms and acetate oxygen atoms. The lengths of the Zn-N bonds (2.019–2.050 Å) and Zn-O bonds with three acetate groups (1.956–1.958 Å) are typical for zinc complexes, whereas the Zn-O³ bond with one of the acetate groups in molecule A is somewhat longer, 2.009(1) Å; also, there is an additional contact of the zinc atom with the carbonyl oxygen atom of this group (Zn-O⁴ 2.498 Å).     

SYNTHESES,CHARACTERIZATION AND CRYSTAL STRUCTURE OF TETRAMETHYLDIBENZOTETRAAZA[14]-ANNULENE ZINC(II) COMPLEXES CONTAINING AN AXIAL BASE

Abstract

The complexes of Zn(tmtaa) and Zn(tmtaa)L [H₂tmtaa = tetramethyldibenzotetraaza[14]-annulene; L = triethylamine, pyridine (Py) and p-dimethylaminopyridine (p-N(CH₃)₂Py)] were synthesized and characterized by IR, LTV, mass and NMR spectra as well as DSC measurements. The effects of different axial ligands (L) on the spectral properties of the complexes have been studied. The crystal structure of Zn(tmtaa)N(C₂H₅)3 was determined by X-ray diffraction. The crystal belongs to a monoclinic system and the space group is P2₁/n. The cell parameters are a = 11.134(2)A, b = 17.453(4)Å, c= 13.784(3)Å, ? = 106.19(3)°, Z = 4, R₁, =0.0336 and wR₂= 0.0805 for 4539 independent reflections with I <2σ(I). The zinc(II) is coordinated through four nitrogen atoms of tmtaa and a nitrogen of triethylamine to form a five-coordinate square-pyramidal structure. The average bond length of Zn for the four nitrogens of tmtaa is 2.050(2)Å and for a nitrogen of triethylamine is 2.188(2)Å. The displacement of the zinc to the plane of four nitrogens of tmtaa is 0.563(2)Å.     

THE CRYSTALLIZATION BEHAVIOR OF [cis-α-Co(trien)(OX)lCl 2H2O (I), [cis-α-Co(trien)(NO2)2]BF4 (II), [cis-α-Co(trien)(NO2)2]-(cis-α-Co(trien)(OX)]Cl l/2SiF6 (III)

Abstract

Three new compounds were synthesized and their crystal structures determined. For compound (I). [cis-α-Co(trien)(OX)]Cl 2H₂O, CoClO₆N₄C₈H₂₂, triclinic, space group P-l (No. 2) a = 6.980(5), b = 8.801(4), c = 12.554(8) Å, α = 89.07(5)°, ? = 75.74(4)°, γ = 81.44(5)°, V = 738.9(8) ų, cell dimensions were obtained from 24 reflections giving FW = 364.4, Z = 2, F[000) = 380.06, Dcalc=1.634mg m-³, μ = 1.36mm-¹. A total of 1907 data were collected over the range of 4° ≤ 2θ ≤ 45°; of these, 1647 (independent and I≥3σ(I)) were used in the structure analysis. Data were corrected for absorption; transmission coefficients ranged from 0.51754 to 0.73648. The final RF and Rw residuals were 0.033 and 0.042.

For compound (II), [cis-α-Co(trien)(NO₂)₂]BF₄, CoN₆C₆O₄BF₄H₁₈, orthorhombic space group Pbca (No. 61) α= 12.260(10), b=12.880(14), c= 17.940(14)A F=2833(4)A³, cell dimensions were obtained from 24 reflections with 2θ in the range of 4.00–45.00 degrees, FW = 383.98, Z = 8, F(000) = 1571.52, Dcalc= 1.801 mgirT³, μ=1.28mm^_1, λ = 0.70930 Å. A total of 1637 data were collected over the range of 4° ≤ 2θ ≤ 45°; of these, 883 (independent and I≥ 2.5σ(I)) were used in the structure analysis. The final RF and Rw residuals were 0.122 and 0.132.

For compound (III), [cis-α-Co(trien)(OX)][cis-α-Co(trien)(NO₂)₂]Cl-l/2SiF₆, Co₂ClSi-l/2N₁₀C₁₄F₃O₁₂H₃₆, orthorhombic, space group Pbca (No. 61) a = 12.804(10), b= 16.543(10), c = 27.419(23) A, V= 5808(7) ų, cell dimensions were obtained from 25 reflections, FW = 760.85, Z = 8, F(000) = 3136.06, Dcalc= 1.740mg m^?3, 4mU= 1.34 mm-¹, λ = 0.70930 Å. A total of 2657 data were collected over the range of 4° ≤ 2θ ≤ 40°; of these, 1902 (independent and I≥ 2.5σ(I)) were used in the structure analysis. The final RF and Rw residuals were 0.058 and 0.062.     

MOLECULAR RECOGNITION OF AN ORGANIC MOLECULE BY BIS(TETRAFLUOROBORATE)ZINC(II). SYNTHESIS AND CRYSTAL STRUCTURE OF {[Zn(phen)3](BF4)2}2·MNA·(H2O)1.5

Abstract

The 2:1 adduct {[Zn(phen)₃](BF₄)₂}₂·MNA·(H₂O)_1.5 (1) (where phen = 1,10-phenanthroline and MNA = 2-methyl-4-nitrobenzenamine) was prepared by self-assembly and characterized by X-ray crystallography. The central zinc atom in two non-equivalent [Zn(phen)₃]²⁺ cations exhibits distorted octahedral geometry with Zn-N bond distances of 2.151(6)-2.194(6) Å and 2.136(6)-2.210(6) Å, respectively. The 2-methyl-4-nitrobenzenamine molecule is connected with bis(tetrafluoroborate)tris(1,10-phenanthroline)zinc(II) through a hydrogen bond (N13-H13a…F23? 3.044 Å, ?1 - x, 1 - y, - z). High shape specificity was observed in the recognition process.     

SYNTHESIS,CHARACTERIZATION AND ELECTROCHEMICAL STUDIES OF MONO- AND DINUCLEAR COMPLEXES OF NICKEL(II) AND COBALT(II) WITH HEXADENTATE LIGANDS HAVING N2P4 DONOR ATOMS. CRYSTAL STRUCTURE OF [Ni(BDPE)]ClO4)2. CH2Cl2

Abstract

A series of mono- and dinuclear complexes of Ni(II) and Co(II) with two hexadentate ligands α,α′-bis(bis(2-(diphenylphosphino)ethyl)amino)ethane(BDPE) and α,α′-bis(bis(2-(diphenylphosphino)ethyl)-amino)-m-xylene (BDPX) were synthesized and chracterized by means of elemental analyses, molar conductance, magnetic susceptibilities, infrared, electronic and ³¹P NMR data. The molecular structure of a mononuclear Ni(II) complex, [Ni(BDPE)](CIO₄)₂.CH₂Cl₂, was established by single-crystal X-ray diffraction methods. Crystal data: C₅₉H₆₂NiCl₄N₂O₈P₄, M = 1250.98, orthorhombic, space group Pbca, V= 11834.3(7) Å3, Z= 8, a= 10.817(1), b = 31.683(7), c=34.538(1) Å, final R 0.055 (R w = 0.057) for 3118 observed reflections. The Ni(II) ion exists in a slightly distorted square planar geometry, the coordination sites being two phosphorous and two tertiary nitrogen atoms of the ligand. Electrochemical studies of the complexes were also carried out.     

A zinc(II) coordination polymer, [Zn4( o -bda)4( p -pbim)4] n,with strong blue fluorescence

A zinc(II) coordination polymer, [Zn₄(o-bda)₄(p-pbim)₄] _n (1) (p-pbim = 4-pyridylbenzimidazole, o-bda^2? = o-phenylenediacetic acid dianion), has been synthesized by hydrothermal method and characterized by elemental analysis, IR, TG, photoluminescence and X-ray single crystal diffraction. Complex 1 crystallizes in a monoclinic system and space group P2₁ /n, with a = 14.231(3) Å, b = 16.257(4) Å, c = 16.794(4) Å, β = 100.262(1)°, and Z = 8; R ₁ for 6475 observed reflections [I > 2σ(I)] was 0.0420. Complex 1 shows a bi-chain structure fabricated by the tetranuclear zinc unit. Two zinc(II) ions are five coordinate with distorted trigonal-bipyramid geometry; the other two zinc(II) ions are four coordinate with distorted tetrahedral geometry. Complex 1 builds the 1-D bi-chain structure with two different subrings A and B, which are 32-member and 14-member rings, respectively. There exists a 2-D supramolecular network linked by hydrogen-bonding interactions (2.695 and 2.807 Å). A 3-D supramolecular network is further constructed by non-covalent interactions between the 1-D bi-chain structure. The TG/DTG shows that the chain skeleton is thermally stable to 356°C. Blue fluorescent emission of the complex was determined at 404 nm in the solid state with short decay lifetime of 1.67 ns.     

Structure of Perchlorato(2,5,8,11-Tetraazadodecane)Copper (II) Perchlorate Monohydrate

[Cu(C₈H₂₂N₄)]·(ClO₄)₂.H₂O, M_r= 454.80, orthorhombic C222₁, a = 15.481(5), b = 7.404(1), c = 14.827(3)Å, V = 1699.5(8)ų, Z = 4, D_x = 1.78 g/cm³, λ(MoKα) = 0.71073Å, μ = 16.5 cm^?1. F(000) = 940, T = 22°C, R = 6.86%, R_w = 7.66% for 820 observed reflections (I > 2.5σ (I)). The coordination number for the copper(II) ion is five, and the coordination geometry about copper(II) ion is a buckled square pyramid with the tetraamine equatorial and a perchlorate ion axial. The tetraamine is coordinated in a square-plannar manner with slight tetrahedral distortions. The four Cu-N distances span a very narrow range, 1.990(10) ?1.994(14)Å.     

Structural Relationships between the Hemiporphyrazine Macrocyclic Ligand and its Metal Complexes. II.: Planar Neutral Ligand,C26H16N8, and Four Isomorphous Metal Complexes, [M(C26H16N8)(H2O)], M=Mn(II), Co(II), Cu(II), Zn(II)

Crystal and molecular structures of the planar neutral ligand, C₂₆H₁₆N₈, and the four isomorphous five-coordinated metal complexes, [M(C₂₆H₁₆N₈)(H₂O)], M = Mn(II), Co(II), Cu(II), Zn(II), have been determined from three-dimensional X-ray diffraction data. The free ligand hpH₂, C₂₆H₁₆N₈, belongs to the P 2₁/c space group with Z=2, a=4.142(3), b=23.736(6), c=10.338(3) Ä, β=94.66(6)°. The metal complexes monohydrate Mhp-H₂O all belong to the orthorhombic Pcab space group with Z=8. The dimensions are roughly 8.8×19.3×23.7 ų. In each structure, the macrocyclic ligand has an almost planar conformation which differs from the saddle shaped ligand hydrate (hpH₂·H₂O) and the nickel complex [Nihp]⁵. The distances from the center of the macrocyclic ring to the nitrogen atom of the free ligand are 1.907(6) and 2.245(6)Å. The coordination geometry in these four complexes is square pyramidal with a water molecule as an axial ligand. The bond distances of M(II)-O(H₂O), M(II)-N1 (imine), M(II)-N3 (pyridine) are: 2.19(1), 2.00(2), 2.27(2)Å respectively for the manganese complex; 2.08(1), 1.97(1), 2.23(1)Å for the cobalt complex; 2.33(1), 1.92(3), 2.18(1)Å for the copper complex; 2.110(5), 1.964(6), 2.252(6)Å for the zinc complex. The variation of metal-ligand distances can be correlated to the metal d orbital occupancy. A comparison with similar ligands will be presented.     

TRANSITION METAL COMPLEXES WITH HYDRAZIDES AND HYDRAZONES. PART 81. X-RAY CRYSTAL STRUCTURE OF A CATENA-POLYBROMO (ACETONE-1-NAPHTHOYLHYDRAZONE) COPPER(II)-COPPER(I) COMPLEX

Abstract

The title compound [Cu₃Br₄C₂₈H₂₈N₄O₂] is a type of polymeric three-centre octahedral-trigonal planar coordination complex. The copper(II) atom located at a centre of symmetry is six-coordinate with two bidentate (N3, O1) ligands of acetone-1-naphthoylhydrazone forming the equatorial plane and two bromine ions in axial positions (Cul-Brl = 2.946(1)Å). The ligands are in trans positions. The Cu(I) atoms are in trigonal planar coordination by two bridging Br^? ions (Cu2-Br2 = 2.412(1)Å, Cu2-Br2? = 2.407(2)Å) which connect two Cu(I) atoms and a third bromine ion shared with the octahedral Cu(II) ion (Cu2-Br1 = 2.304(1)Å). The arrangement forms an infinite chain along the b axis.     

STRUCTURE AND PROPERTIES OF N,N-DI-n-BUTYLDITHIOCARBAMATO-1, 2-DICYANOETHENE-1, 2-DITHIOLATO-GOLD(III)

Abstract

The crystal and molecular structure and some spectral data of the compound N,N-di-n-butyldithiocarbamato-1, 2-dicyanoethene-1, 2-dithiolato-gold(III), AuS₂CN(C₄H₉)₂S₂C₂(CN)₂, are reported. The crystal structure has been determined from a three-dimensional single-crystal X-ray diffraction study. The orthorombic cell, space group Pbca, with a=14.066(3), b=28.980(2) and c=9.192(2) Å, contains eight formula units. Intensity data were collected on an automatic diffractometer. The structural parameters were refined by full-matrix least-squares methods to a conventional R-factor of 0.047 for 1587 independent non-zero reflections. The structure determination proved the compound to be a mixed dithiocarbamato-dithiolato complex, Au(dtc)(mnt), (dtc=N,N-di-n-butyl-dithiocarbamate, mnt=maleonitriledithiolate ≡ 1, 2-dicyanoethene-1, 2-dithiolate), as expected from spectral data. The gold atom is in approximately square-planar coordination, however, deviations from mm2 (C_2#) symmetry are considerable. Au-S bond distances in the dtc-moiety (2.329(5) Å and 2.324(5) Å) are significantly longer than those in the mnt-moiety (2.303(5) Å and 2.284(5) Å). The molecules are packed pairwise around inversion centres with relatively short intermolecular S-S distances.     

The Syntheses and crystal structures of trans-dichlorobis (10-thiabenzo-15-crown-5)-palladium(Ⅱ)and trans-dichlorobis-(10-selenabenzo-15-crown-5)palladium(Ⅱ)

The preparation and X-ray crystal structures of the adducts of 10-thiabenzo-15-crown-5 and 10-selenabenzo-15-crown-5 with PdCl2 are reported. [PdCl2(C14H20O4S)2] (1): or-thorhombic, space group Pbca with cell dimensions of a=17.285(5), 6=8.354(3), c=21.689(4) A, K=3131.9 A3, Z=4;R=0.0330 for 2301 reflections with I > 3o(I), [PdCl2(C14H2oO4Se)2] (2): monoclinic, space group P21/n with cell dimensions of a=18.928(4), b=8.912(3), c=9.813(2) A, β=96.90(2)0, V=1643.4 A3, Z=2; R=0.0289 for 2617 reflections with I> 3σ(I), Both complexes are monomeric, square-planar palladiurn(Ⅱ) compounds with the Pd(Ⅱ) ion situating on a crystal-lographic inversion centre, and the crown ligands all adopt the axial coordination with the Pd-S bond of 2.3233(7) A and the Pd-Se bond of 2.4357(3) A. Their complexing characteristics are discussed in brief.     

STRUCTURES OF PYRIDINE CARBOXYLATE COMPLEXES OF COBALT(II) AND COPPER(II)

Abstract

The syntheses and crystal structures of [Co(nic)₂(H₂O)₄] (1). [Co(iso)₂(H₂O)₄] (2). [Cu(nic)₂(H₂O)₄] (3), and [Cu(iso)₂(H₂O)₄] (4) (nic = nicotinate; iso = isonicotinate) are reported. Complex 1 crystallizes in monoclinic, space group C2/m with cell parameters a =14.150(4). b = 6.883(2)., c = 8.497(2) Å, β= 118.28(2)° and Z = 2. The other crystals. 2. 3. and 4. are all triclinic, Pī; a = 9.777(3), b = 6.348(4), c = 6.888(3)Å, a= 113.10(6)., β= 110.55(3). γ = 97.61(5)°, and Z=l for 2; a = 7.0281(4), b = 7.7176(6), c = 8.6978(7)Å, a = 68.103(7), β = 68.526(5), γ = 62.550(6)°, and Z=1 for 3; a = 9.1807(4), b = 6.3334(3), c = 6.8871(3)Å, a= 108.213(4), β = 99.433(4), γ= 105.190(4)°, and Z= 1 for 4. The arrangements around the metal ions are trans-octahedra with two pyridyl nitrogens and two aqua oxygens in the equatorial positions and two aqua oxygens in the axial positions, although the Cu(II) complexes show a larger Jahn-Teller distortion.     

Mononuclear Complexes of Cr(II) and Fe(II) with Terminal -SH Groups. Synthesis and X-Ray Crystal Structures of trans-M(SH)2(dmpe)2 (M = Cr,Fe; dmpe = 1,2-Bis(Dimethylphosphino)Ethane)

Abstract

The reaction of two equivalents of NaSH with MCl₂(dmpe)₂ (M = Cr, Fe,) at—78°C gives trans-M(SH)₂(dmpe)₂ (M = Cr, (1), 30%; Fe, (2) 98%). The complexes have been characterized spectroscopically, and the trans geometry has been confirmed by single crystal X-ray diffraction studies. Crystal data (1): C₁₂H₃₄CrP₄S₂, M= 418.42, monoclinic, P2₁/n, a = 8.857 (I), b= 12.719 (2), c = 9.648 (I) Å, β = 92.14(1)°, U= 1086.2 (5)Å, D _c = 1.279gcm^?3, Z = 2, λ(MoK_a) = 0.71073 Å, (graphite mono-chromator), μ(MoK_a) = 9.80cm^?1. Methods: MULTAN, difference Fourier, full-matrix least-squares. Refinement of 1149 reflections (I > 3σ(I)) out of 1901 unique observed reflections (3.0° < 29 < 48.0°) gave R and R _w values of 0.092 and 0.096, respectively. Crystal data (2): C₁₂H₃₄FeP₄S₂, M = 422.28, monoclinic, P2₁/n, a = 8.834 (2), b = 12.594 (2), c = 9.532 (2) Å, β = 90.66 (2)°, U = 1060.3 (5) ų, D _c = 1.323 g cm^?3, Z = 2, γ(MoK_a) = 0.71073 Å, (graphite monochromator), μ(MoK_a) = 11.87 cm^?1. Methods: same as for (1). Refinement of 1178 reflections (I > 3σ (I)) out of 2086 unique observed reflections (2.0° < 20 < 50.0°) gave R and R _w values of 0.056 and 0.059, respectively.     

Copper(II) Halide Complexes of 2-Aminopyrimidines: Crystal Structures of [(2-aminopyrimidine) n CuCl2] (n=1,2) and (2-amino-5-bromopyrimidine)2CuBr2

The reaction of CuX₂(X=Cl, Br) with 2-aminopyrimidine in aqueous solution, or 2-amino-5-bromopyrimidine in aqueous acid yields compounds of the forms [LCuCl₂] _n (1), [L₂CuCl₂] (2) and [L'₂CuBr₂] (3) [L=2-aminopyrimidine; L'=2-amino-5-bromo-pyrimidine]. The three compounds all form layered structures in which each copper ion is coordinated to two 2-aminopyrimidine molecules and two halide ions. Common structural threads involve bridging ligation [either by monomeric (1) or hydrogen bonded ligand dimers (2 and 3)], N-H···X and N-H···N hydrogen bonding and π-π stacking interactions as well as semi-coordinate Cu···X bond formation (1 and 2) or Br···Br interactions (3). Compounds 1 and 2 crystallize as two-dimensional coordination polymers with asymmetrically bihalide bridged (CuX₂) _n chains cross-linked into sheets by the 2-aminopyrimidine molecules (1) or by hydrogen bonded L₂ dimers (2). The halide bibridged chains expand their primary copper coordination spheres to give 4 + 2 coordination spheres in 1 and 2. In 3, the layer structure involves coordination of the hydrogen bonded L'₂ dimers and C-Br···Br- interactions. Crystal data: (1): monoclinic, P2₁/m, a=3.929(1), b=12.373(2), c=7.050(1)å, β=91.206(4)°, V=342.7(1)&Aringsup3;, Z=2, D _calc= 2.225Mg/m³, μ=3.878 mm^-1, R=0.0269 for [|I|≥3σ(I)]. For (2): triclinic, P-1, a=4.095(4), b=7.309(5), c=10.123(6) å, α=86.28(6), β=78.44(6), γ=74.55(8)°, V=286.1(4) ų, Z=1, D _calc=1.884 Mg/m³, μ=2.360 mm^-1, R=0.0506 for [|I|≥2σ(I)]. For (3): triclinic, P-1, a=6.074(4), b=7.673(3), c=8.887(3) å, α=108.43(3) β=100.86(5), γ=106.96(4)°, V=357.0(3) ų, Z=1, D _calc=2.657 Mg/m³, μ=12.714mm^-1, R=0.0409 for [|I|≥2σ(I)].     

Synthesis and Crystal Structures of Two Zinc(II) Complexes with the Tripodal Ligand Tris(2-Benzimidazolymethyl)Amine

This article reports the synthesis and crystal structures of two new mononuclear Zinc(II) complexes, [Zn₂(NTB)₂(N₃)₂](NO₃)₂·2CH₃OH (1) and [Zn₂(NTB)₂(SCN)₂](NO₃)₂·2CH₃OH·H₂O (2). Complex 1 crystallizes in the triclinic system, space group P&1macr;, a=13.743(4), b=14.374(4), c=14.443(5) Å; α=77.053(5), β=81.824(5), γ=88.959(6)°; Z=2; R1=0.0418, wR2=0.0889. Complex 2 also crystallizes in the triclinic system, space group P&1macr;, a=12.203(10), b=14.430(12), c=18.541(15)Å; α=72.712(15), β=85.039(15), γ=73.610(14); Z=2; R1=0.0771, wR2=0.1288. In both cases the central zinc(II) metal ions are coordinated to the four nitrogen atoms of NTB and a nitrogen atom of N^- ₃(1) or SCN^-(2) to form distorted trigonal bipyramidal coordination spheres.     

Crystal and Molecular Structure of Carbonyl (1,1,4,4-Tetrafluoro-2-tert-Butyl-1,4-Disilabut-2-Ene) (η5-Cyclopentadienyl) Cobalt (II)

(C₃H₅)Co(CO)(Si₂F₄C₄H₁₀) was synthesized by the photochemical reaction between dicarbonyl (η⁵-cyclopentadienyl) cobalt and 1,1,2,2-tetrafluoro-1,2,-disilacyclobutene. Its structure was identified by IR, NMR and mass spectrometry. The single crystal structure was studied for confirmation. The compound crystalized in a monoclinic space group P2₁/n with unit cell a=7.120 (6), b=20.334. (3), c=10.682(1) Å, β=90.97(8)°, Z=4 final R=0.050 for 3667 observed reflections. The molecule has a mirror plane symmetry about the Co atom coordination sphere. The reaction between the cobalt carbonyl and the 1,2-disilacyclobutene produces only silicon-cobalt σ bonds.     

Crystal structures of two Ca(II) complexes with imidazole-4,5-dicarboxylate and water ligands

The structure of compound I: poly-diaqua(μ-imidazole-4,5-dicarboxylato-N,O; -O′; -O′′, -O′′′) calcium(II) monohydrate [Ca(C₅H₂N₂O₄)(H₂O)₂·H₂O] is built of molecular sheets in which imidazole-4,5-dicarboxylate ligands bridge the metal ions using both carboxylate groups, each bidentate. Ca(II) is coordinated by six oxygen atoms and one hetero-ring nitrogen atom distributed at the apices of a capped tetragonal bipyramid. The basal plane of the pyramid is formed by two carboxylate oxygen atoms [d(Ca–O2?=?2.374(1)?Å, d(Ca–O4)?=?2.412(1)?Å] and two water oxygen atoms [d(Ca–O5)?=?2.384(1)?Å, d(Ca–O6)?=?2.455(1)?Å], the capped position is occupied by the carboxylate oxygen atom O3 [d(Ca–O3)?=?2.325(1)?Å], the hetero-ring nitrogen atom [d(Ca–N2)?=?2.523(1)?Å] and the carboxylate oxygen atom O4 [d(Ca–O2)?= 2.412(1)?Å] form the apices of the prism. The solvation water molecule plays a significant role in a framework of hydrogen bonds responsible for the stability of the crystal. The structure of compound II: trans-tetraquadi(H-imidazole-4,5-dicarboxylato-N,O) calcium(II) monohydrate, [Ca(C₅H₃N₂O₄)₂(H₂O)₄·H₂O] consists of monomers in which the Ca(II) ion is located on a centre of symmetry. The coordination around the Ca(II) is a strongly deformed pentagonal bipyramidal with the imidazole-4,5-dicarboxylate (4,5-IDA) ligands in the trans arrangement forming a dihedral angle of 68.3°. An imidazole-ring nitrogen atom [d(Ca–N)?=?2.632(2)?Å] and one carboxylate O atom [d(Ca–O)?=?2.531(2)?Å] from each ligand coordinate to the metal ion. The coordination is completed by four water oxygen atoms [d(Ca–O)?=?2.393(2)?Å] and [d(Ca–O)?=?2.367(2)?Å]. The coordinated water molecules act as hydrogen bond donors and acceptors to the unbonded carboxylate oxygen atoms in adjacent monomers giving rise to a three-dimensional molecular network.     

CRYSTAL STRUCTURE AND THERMAL ANALYSIS OF A 4,4′-BIPY-BRIDGED BINUCLEAR ZINC(II) COMPLEX, 2[R2NCS2]2 · Zn(4,4′-BIPY) (R=PIPERIDYL)

Abstract

The crystal structure of the title complex 2[R₂NCS₂]₂ · Zn(4,4′-bipy) (R = Piperidyl), 1, revealed that it consists of dimers made up from two crystallographically independent molecules. Each zinc atom in 1 forms a 5-coordinate pseudo-square-based pyramidal arrangement (with four Zn-S and one Zn-N interactions). Bondlengths to Zn with the coordinating atoms are comparable to those in other Zn(II) dithiocarbamate complexes. The piperidine ring has a chair conformation. To allow improved packing, the title complex molecules form an approximately linear arrangement extending along both a and b. TGA showed that 1 is decomposed in two close steps to produce ZnS as identified by residual weight. The complex 1 crystallizes in the monoclinic space group C2/c with cell parameters: a = 22.021(5), b = 22.215(3), c = 17.537(2) Å, β = 93.49(2)°, V = 8563(3) ų and Z = 8. The structure was refined by full-matrix least-squares methods to R = 0.067, R_w = 0.114.     

Molecular Structure of Diperchloratotetraphenylporphinatotin(IV)

X-ray diffraction data and NMR spectra of diperchloratotetraphenylporphinatotin(IV), Sn(tpp)(ClO₄)₂ provide evidence for a monodentate perchlorato group coordinated to the Sn(IV) atom. The molecule Sn(tpp)(ClO₄)₂ displays an octahedral coordination geometry for the tin atom and its crystal belongs to the monoclinic space group P2₁/n with a = 11.241(3), b = 14.644(3), c = 12.173(3) Å,β = 111.18(2)°, and Z = 2. The structure was solved by direct method, 3996 unique reflections having I > 3σ(I) measured with an automated diffractometer were used to refine the crystal structure to a conventional R factor 0.0431. The tin(IV) ion is centered on a planar tpp moiety. The geometry at the octahedral coordination centre of the Sn(tpp) (ClO₄)₂ molecule has Sn-O(perchlorate) = 2.181 Å and Sn-N = 2.073 Å.