Crystal structure of a dimeric nickel(II) complex with 3-imidazoline nitroxide radical

The crystal structure of an unusual dimeric Ni(II) complex with 3-imidazoline nitroxide LH=C₉H₁₄N₂O₂ of the formula Ni₂(LH)₄ has been determined. The structure is molecular, space group P2₁/c, with a=12.150(3) Å, b=11.229(3) Å, c=15.780(4) Å, =101.59(3)^o, and d _calc =1.54 g/cm³, for Z=2; V=2109(1) ų, R=0.059. In the centrosymmetric dimer, the Ni...Ni distance is 3.254(2) Å; the coordination polyhedron of Ni is a square pyramid (the coordination number is 5) formed by the donor O and N atoms of LH ligands acting as the bidentate-cyclic and bidentate bridged-cyclic structures. The Ni–O and Ni–N distances are 1.989(7) and 2.032(8) Å, respectively (for the atoms forming the pyramid base), and 2.000(8) Å to the apical N atom. The Ni atom is displaced from the base to the apex of the pyramid by 0.35 Å. The interatomic distances and the bond angles in the ligands agree with those for the previously studied M(LR)₂ complexes. The distances between the Ni(II) ions and the O O atoms inside the Ni(LH)₂ fragments are 5.39(1) and 5.45(1) Å, the intermolecular Ni...O distances exceed 6 Å, and the O...O distances are as long as 4.73(1) Å.Institute of Inorgamic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Stukturnoi Khimii, Vol. 34, No. 3, pp. 80–85, May–June 1993.Translated by T. Yudanova     

Quantum-chemical study on the tautomerism of primary nitramines: the mechanism of N-nitro-anion protonation excludingaci-form formation

The values of the energy barriers to intramolecular 1,3-H shift reactions, in whichaci-forms of N- and C-nitro-compounds: 1 and are capable of transforming into 2 and , respectively, have been calculated by the semi-empirical AM1 method. The barrier heights (39 and 59.4 kcal/mol) reflect the kinetic stability of both tautomeric forms of the N- and C-nitro-compounds.Ab initio calculations in the 3–21G basis set of the structure and energies of stationary points on the potential energy surface of the system MeN=NO₂ H₃O demonstrated that there exists the principal possibility of the formation of only tautomer 2 (which is more stable than1).Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No 1, pp. 100–104, January, 1993.     

Hydrogen bonds and protonation of carbonyl-containing polynuclear rhodium complexes

According to IR spectroscopy data, the interaction of bi-, tri-, and tetranuclear cyclopentadienylcarbonyl rhodium complexes with rather weak protic acids (phenols, fluoroalcohols) in low-polarity media results in the formation of hydrogen bonds of the OH...O=C type with bridged carbonyl groups. According to¹H NMR data, protonation of these complexes with strong acids (CF₃COOH and HBF₄) occurs at the the Rh-Rh bond to give the symmetrical bridge.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 386–388, February, 1995.This work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-0461).     

Synthesis, Properties, and Crystal and Molecular Structures of New Ni(II) Complexes with Sterically Hindered Methoxy-β-iminoketones

This paper describes a procedure for the synthesis of two new volatile complexes, C₂₂H₄₀N₂NiO₄ and C₂₀H₃₆N₂NiO₄, based on sterically hindered methoxy--iminoketones. The compounds were investigated by IR spectroscopy and DTA. Full crystal-chemical analysis has been carried out. The structures are molecular. The complexes have close geometrical characteristics; the distances are Ni–O 1.826 and Ni–N 1.842 ; the O–Ni–N chelate angle is 93.2°. The complexes have an intramolecular hydrogen bond N–H...O, estimated at 2.54 (2.08) . In both structures, the packing of complexes is similar to that in nickel(II) dipivalylmethanate.     

Two-Dimensional Coordination Polymer {[Zn(Pht)(4.4′-Bipy)(H2O)2] · 2H2O} n : Synthesis and Structure

The coordination polymer {[Zn(Pht)(4,4-Bipy)(H₂O)₂] · 2H₂O} _n (where Pht is a doubly deprotonated phthalic acid residue and 4,4-Bipy is 4,4-bipyridine) was synthesized and studied by X-ray diffraction. It was shown that both ligands perform a bridging function and unite the Zn atoms into a two-dimensional network with a periodicity of 11.302(2) Å (with 4,4-Bipy as the bridge) or 7.627(2) Å (with Pht as the bridge). The coordination polyhedron of Zn is a distorted octahedron with C ₂ symmetry. The Zn–N distances in the coordination polyhedron are 2.117(3) and 2.131(3) Å; the Zn–O_carb distance is 2.171(2) Å and the Zn–O(w) distance is 2.129(2) Å. The O–H···O hydrogen bonds involving the outer-sphere water molecules combine the polymer layers into a framework.     

Synthesis and Crystal Structure of a New Copper–PMIDA Compound (H4PMIDA=H2O3PCH2N(CH2CO2H)2)

A new Cu(II)PMIDA compound [Cu(H₂PMIDA)(phen)] 3H₂O (1) (H₄PMIDA = H₂O₃PCH₂N (CH₂CO₂H)₂,phen = 1,10-phenanthroline) has been successfully synthesized and structurally characterized. In complex 1, Cu (II) is six coordinated by chelation in a tetradentate fashion by a PMIDA ligand and by two N atoms of a phen ligand. Every phen–Cu(II)–PMIDA group connects with each other via a hydrogen bond and the edge-to-face -stacking interaction. Complex 1 crystallized in triclinic P-1 with cell dimensions of a = 7.5817(6) Å, b = 10.6980(8) Å, c = 13.1852(10) Å, =82.350(2)°, = 84.151(2)°, =78.4250(2), V= 1035.25(14) ų, Z = 2, Dc = 1.677 Mg/m³.     

Kristallstruktur von Monosilber(I)amidosulfat,AgSO3NH2

A crystal structure analysis of the colourless AgSO₃NH₂ was carried out at room temperature:M=203.95, orthorhombic, Pcab,a=7.809 (2) Å,b=8.067 (2) Å,c=11.682 (3) Å,V=735.9 ų,Z=8,d _x=3.681 Mgm^–3,F(000)=760, Mo K, =0.71069 Å (graphite monochromator), =5.77 mm^–1,R=4.36% (509 reflections, 56 parameters). The ionic structure shows approximate trigonal bipyramidal coordination around the Ag⁺-ions.

     

On the crystal chemistry of three copper(II)-arsenates: Cu3(AsO4)2-III,Na4Cu(AsO4)2, and KCu4(AsO4)3

The three copper(II)-arsenates were synthesized under hydrothermal conditions; their crystal structures were determined by single-crystal X-ray diffraction methods:Cu₃(AsO₄)₂-III:a=5.046(2) Å,b=5.417(2) Å,c=6.354(2) Å, =70.61(2)°, =86.52(2)°, =68.43(2)°,Z=1, space group ,R=0.035 for 1674 reflections with sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a=4.882(2) Å,b=5.870(2) Å,c=6.958(3) Å, =98.51(2)°, =90.76(2)°, =105.97(2)°,Z=1, space group ,R=0.028 for 2157 reflections with sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a=12.234(5) Å,b=12.438(5) Å,c=7.307(3) Å, =118.17(2)°,Z=4, space group C2/c,R=0.029 for 1896 reflections with sin / 0.80 Å^–1.Within these three compounds the Cu atoms are square planar [4], tetragonal pyramidal [4+1], and tetragonal bipyramidal [4+2] coordinated by O atoms; an exception is the Cu(2)^[4+1] atom in Cu₃(AsO₄)₂-III: the coordination polyhedron is a representative for the transition from a tetragonal pyramid towards a trigonal bipyramid. In KCu₄(AsO₄)₃ the Cu(1)^[4]O₄ square and the As(1)O₄ tetrahedron share a common O—O edge of 2.428(5) Å, resulting in distortions of both the CuO₄ square and the AsO₄ tetrahedron. The two Na atoms in Na₄Cu(AsO₄)₂ are [6] coordinated, the K atom in KCu₄(AsO₄)₃ is [8] coordinated by O atoms.Die drei Kupfer(II)-Arsenate wurden unter Hydrothermalbedingungen gezüchtet und ihre Kristallstrukturen mittels Einkristall-Röntgenbeugungsmethoden ermittelt:Cu₃(AsO₄)₂-III:a = 5.046(2) Å,b = 5.417(2) Å,c = 6.354(2) Å, = 70.61 (2)°, = 86.52(2)°, = 68.43(2)°,Z = 1, Raumgruppe ,R = 0.035 für 1674 Reflexe mit sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a = 4.882(2) Å,b = 5.870(2) Å,c = 6.958(3) Å, = 98.51(2)°, = 90.76(2)°, = 105.97(2)°,Z = 1, Raumgruppe ,R = 0.028 für 2157 Reflexe mit sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a = 12.234(5) Å,b = 12.438(5) Å,c = 7.307(3) Å, = 118.17(2)°,Z = 4, Raumgruppe C2/c,R = 0.029 für 1896 Reflexe mit sin / 0.80 Å^–1.Die Cu-Atome in diesen drei Verbindungen sind durch O-Atome quadratisch planar [4], tetragonal pyramidal [4 + 1] und tetragonal dipyramidal [4 + 2]-koordiniert; eine Ausnahme ist das Cu(2)^{[4 + 1]}-Atom in Cu₃(AsO₄)₂-III: Das Koordinationspolyeder stellt einen Vertreter des Übergangs von einer tetragonalen Pyramide zu einer trigonalen Dipyramide dar. In KCu₄(AsO₄)₃ haben das Cu(1)^[4]O₄-Quadrat und das As(1)O₄-Tetraeder eine gemeinsame O—O-Kante von 2.428(5) Å, was eine Verzerrung der beiden Koordinationsfiguren CuO₄-Quadrat und AsO₄-Tetraeder bedingt. Die zwei Na-Atome in Na₄Cu(AsO₄)₃ sind durch O-Atome [6]-koordiniert, das K-Atom in KCu₄(AsO₄)₃ ist [8]-koordiniert.

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Zur Kristallchemie dreier Kupfer (II)-Arsenate: Cu₃(AsO₄)₂-III, Na₄Cu(AsO₄)₂ und KCu₄(AsO₄)₃

     

Tetracarbonyliron adducts of Cp2Cr2(CO)4(μ-η2-P2). Syntheses and crystal structures of Cp2Cr2(CO)4P2[Fe(CO)4] m (m=1 and 2)

Cp₂Cr₂(CO)₄( - ² - P₂), 1, reacts with one molar equivalent of Fe₂(CO)₉ in THF to yield the mono- and di-iron complexes, Cp₂Cr₂(CO)₄P₂[Fe(CO)₄], 2, (16.5% yield) and Cp₂Cr₂(CO)₄P₂[Fe(CO)₄]₂, 3, (16.9% yield), as dark magenta brown and dark greenish brown crystals, respectively. Both complexes were characterized by single-crystal X-ray diffraction analysis. Crystal data –2: space group =P2₁/c,a=17.024(1) Å,b=8.180(1) Å,c=30.891(2) Å, =100.953(5)°,V=4223.4(7)ų,Z=8, 3743 observed reflections,R _F=0.033; 3: space group P1,a=10.209(2) Å,b=10.212(2) Å,c=15.989(3) Å, =106.93(1)°, =91.87(1)°, =119.50(1)°,V=1356.5(4) ų,Z=2, 3489 observed reflections,R _F=0.029.     

Nickel complexes of 1-methylimidazoline-2(3H)-thione: crystal structures of trans-dichlorotetrakis(1-methylimidazoline-2(3H)-thione)nickel(II) and tetrakis[1-methylimidazoline-2(3H)-thione]nickel(II) tetrafluoroborate

Summary Crystal structures have been determined for two nickel complexes of the monodentate S-donating ligand 1-methyl imidazoline-2(3H)-thione (mimtH). The parainagnetic trans-octahedral complex, [Ni(mimtH)₄Cl₂], crystallises in an orthorhombic unit cell (a=12.459(1),b=13.078(1),c=15.406(1)Å, V=2510.24ų,Z=4, space group Pbca). Final conventional R from 1848 observed data [F>4(F)] is 0.0273. The Ni–Cl distance is. 2.537(1) Å and the mean Ni–S distance is 2.479 Å.The diamagnetic complex, [Ni(mimtH)₄](BF₄)₂, contains a distorted square-planar cation which is H-bonded. to [BF₄]^– anions. The complex crystallises in an orthorhombic unit cell [a=9.810(1),b=14.585(1),c=20.120(2)Å, V=2878.8ų,Z=4, space group Pbcn]. Final conventional R from 1756 observed data [F>4(F)] is 0.0629. The average Ni–S distance is 2.216Å.     

X-ray Diffraction Structural Study of Acid Pyridinium Hexamolybdochromate(III)

Acid pyridinium hexamolybdochromate(III) (₅₅NH)H₂[CrMo₆O₁₈(OH)₆] · 6H₂O was synthesized and structurally characterized. The crystals are monoclinic, space group P2₁/c, a = 11.400(2) Å, b = 11.165(2) Å, c = 11.665(2) Å, = 104.39(3)°, Z = 2, _calcd = 2.789 g/cm³.     

Observedtrans influence of donor atoms in monocharged bidentate ligands: Crystal structure of the acetone solvate of 2-carboxyquinolinatocarbonyltriphenylphosphinerhodium(I)

Summary 2-Carboxyquinolinatocarbonyltriphenylphosphinerhodium(I), [Rh(Quin)(CO)(PPh₃)], was prepared by replacement of CO by PPh₃ in the corresponding dicarbonyl. The compound crystallizes in the triclinic space group Åb=17.168(6) Å,c=9.254(5) Å, =101.49(5)°, =95.74(4)°, =98.41(4)°, d_cxp=1.45g cm^–3 and Z=2. The crystal structure was dermined from 3496 observed reflections. The final R value was 0.061. This structure determination indicates that the nitrogen atom of the chelate ring has the largesttrans influence since the carbonyl grouptrans to this atom was substituted by the PPh₃ ligand. The effects of different donor atoms in bidentate ligands, as well as the ring size of the chelate ring, on the relativetrans influence of the donor atoms are discussed.     

Complexation with diol host compounds. Part 1. Structures of the 1:2 molecular complexes oftrans-9, 10-dihydroxy-9,10-diphenyl-9,10-dihydroanthracene with acetophenone and with 3-methylcyclopentanone

The structures of the 1:2 molecular complexes of trans -9,10-dihydroxy-9,10-diphenyl-9,10-dihydroanthracene with acetophenone (1), (C₂₆H₂₀O₂·2 C₈H₈O) and with 3-methylcyclopentanone (2), (C₂₆H₂₀O₂·2C₆H₁₀O) have been determined by X-ray crystallography. The crystal data are as follows: Compound (1):P ,a =8.979(5) Å,b =9.316(3) Å,c = 11.12(1) Å, =94.40(6)°, = 106.53(6)°, = 109.92(5)°,V = 822.94 ų,Z = 1,R = 0.097 for 2549 unique reflections. Compound (2):P ,a = 8.958(7) Å,b =9.815(4) Å,c = 9.807(4) Å, = 96.88(3)°, = 109.21(8)°, = 103.33(7)°,V = 774.10 ų,Z = 1,R = 0.059 for 2494 unique reflections. The intermolecular arrangements in both structures are characterised by host-to-guest hydrogen bonding interactions. The thermal properties of compound (2) have been characterised by DTA and TGA thermograms.     

Crystal structure of copper(II) bis-hexafluoroacetylacetonate

An X-ray diffraction investigation has performed for copper(II) bis-hexafluoroacetylacetonate (Bruker AXS P4 automatic diffractometer, MoK radiation, t = –25°C). Crystal data for C₁₀H₂CuF₁₂O₄: a = 5.530(1) Å, b = 6.038(1) Å, c = 11.266(2) Å, = 95.948(3)°, = 101.743(3)°, = 92.298(3)°, space group; P1, V = 365.6(1) ų, Z = 1, d _calc = 2.169 g/cm³. The square-planar environment of the copper atom (Cu-O_av 1.912 Å, O-Cu-O_av 93°) is completed to bipyramidal by two fluorine atoms of the neighboring molecules, Cu...F 2.71 Å and 2.75 Å.Original Russian Text Copyright © 2004 by S. A. Gromilov, I. A. Baidina, P. A. Stabnikov, and G. V. RomanenkoTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 502–507, May–June 2004.     

Antimony(III) Oxofluorides α-Sb3O2F5 and β-Sb3O2F5: Synthesis and Crystal Structures

The conditions for the synthesis of two polymorphous forms of antimony(III) oxofluoride Sb₃O₂F₅ from aqueous solutions are established. The crystal structure of a new polymorphous modification -Sb₃O₂F₅ is determined (monoclinic crystals with a = 6.9548(6) Å, b = 9.1043(7) Å, c = 20.336(2) Å, = 94.167(2)°, V = 1284.2(2) ų, Z = 8, (calcd) = 5.092 g/cm³, F(000) = 1712, space group P2₁/n) and the structure of -Sb₃O₂F₅ is refined. The geometric characteristics of crystal structures of antimony(III) oxofluorides SbOF (L- and -forms) are compared with those of Sb₃O₂F₅ (- and -forms).     

A spin-trap ESR study of the decomposition of alkyl formates

Conclusions By using nitroso compound ESR spin traps it has been shown that the alkyl formates break down into radicals under irradiation at 2537 Å and 25°C, and this regardless of whether or not the system contains added tert-butyl peroxide. The mechanism of breakdown varies with the alkyl-formate structure, Under our conditions of irradiation, the product radicals were as follows: OOCH₃ from methyl formate; OOCH₂CH₃ and HCOOHCH₃ from ethyl formate; OOC(CH₃)₃ and (CH₃)₃ from tert-butyl formate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 542–545, March, 1977.     

Iron Catalysis of SO2 Oxidation in the Atmosphere

The mechanisms of SO₂ oxidation catalyzed by iron ions in the droplet phase of the convective cloud in the lower atmosphere were examined. The relations of the catalytic SO₂ decrease to the concentration of the iron ions and to the intensity of fluxes to the droplet of the OH _(g) and HO _2(g) radicals were characterized. The determining role of the replacement of the low-reactive HO _2(g)(O^– _2(aq)) radical by the reactive SO^– _5(aq) radical in the sulfite medium during daytime was revealed. This process occurred due to the coupling of the decay of the radicals and their regeneration in the liquid-phase reactions O^– _2(aq) + FeOH²⁺ _(aq) Fe²⁺ _(aq) + OH^– _(aq) + O_2(aq), HSO^– _5(aq) + Fe²⁺ _(aq) FeOH²⁺ _(aq) + SO^– _4(aq)HSO ₃ ^- _(aq),O_{2 (aq)} SO^– _5(aq).     

Thermodynamic Study of the Aqueous Rubidium and Manganese Bromide System

Crystallization of 2RbBr · MnBr₂ · 2H₂O, the only double salt obtained under standard conditions from saturated aqueous rubidium–manganese bromide solutions, was theoretically predicted using the hard and soft Lewis acids and bases concept and Pauling's rules. The RbBr—MnBr₂—H₂O system was thermodynamically simulated by the Pitzer model assuming a solubility diagram of three branches only: RbBr, 2RbBr · MnBr₂ · 2H₂O and MnBr₂ · 4H₂O. The theoretical result was experimentally proved at 25°C by the physicochemical analysis method and formation of the new double salt 2RbBr · MnBr₂ · 2H₂O was established. It was found to crystallize in a triclinic crystal system, space group –P1, a = 5.890(1) Å, b = 6.885(1) Å, c = 7.367(2) Å, = 66.01(1)°, = 87.78(2)°, = 84.93(2)°, V = 271.8(1) ų, Z = 1, D _x = 3.552 g-cm^–3. The binary and ternary ion interaction parameters were calculated and the solubility isotherm was plotted. The standard molar Gibbs energy of the synthesis reaction, _rG _m ^o , of the double salt 2RbBr · MnBr₂ · 2H₂O from the corresponding simple salts RbBr and MnBr₂ · 4H₂O, as well as the standard molar Gibbs energy of formation, _fG _m ^o , and standard molar enthalpy of formation _fH _m ^o of the simple and double salts were calculated.     

Synthesis, Characterization, and Physical Properties of Two Trinuclear, Mixed-Valence Species of Type [μ3-OMnIIMnIII 2(O2CCF3)6(R)3] (R=H2O, CH3COOH)

The preparation and characterization of two new mixed-valence, trinuclear species, [Mn₃O(O₂CCF₃)₆(H₂O)₃]CF₃COOH4/3H₂O (1) and [Mn₃O(O₂CCF₃)₆(CH₃COOH)₃] (2), is reported. Compound 1 crystallizes in the triclinic space group, P¯1 (No. 2), with the parameters, a=12.3131(9) Å, b=12.4427(9) Å, c=12.965(1) Å, =72.593(4)°, =73.453(5)°, =68.345(4)°, V=1727.2(2) ų, and Z=2. A total of 14060 reflections were collected in the range 1.6827.52°. The final weighted and non-weighted agreement indices, R1=0.0589 and wR2=0.1445 were based on a total of 6953 unique reflections with an R _int value of 0.0542. Compound 2 crystallizes in the monoclinic space group, P2₁/n (No. 14), with the parameters, a=12.876(3) Å, b=12.212(4) Å, c=17.732(4) Å, =100.40(3)°, V=3640.4(1) ų, and Z=4. A total of 32197 reflections were collected in the range 1.7227.13°. The final weighted and non-weighted agreement factors, R1=0.0647 and wR2=0.1609 were based on a total of 8018 unique reflections with an R _int value of 0.0462. An investigation of the physical properties revealed that both compounds display an intermediate ground state of S=3/2 as a consequence of intramolecular antiferromagnetic coupling. The magnetic data for compound 1 was best fit to the parameters g=2.09, J=–5.5 cm^–1, J=–3.4 cm^–1, and D _Mn(III)=–4.5 cm^–1; the data for compound 2 was best fit to the parameters g=2.10, J=–2.9 cm^–1, J=–5.5 cm^–1, and D _Mn(III)=–4.5 cm^–1.     

Synthesis and X-Ray Crystal Structure Study of ]2-Methyl-4-(2-methylbenzoyl)-phenoxy] Acetic Acid Hydrazide

Benzophenone analog 3 has been synthesized and characterized by the X-ray diffraction (XRD) method. The compound crystallizes in a monoclinic space group P2₁/c with cell parameters a = 7.701(8) Å, b = 7.151(5) Å, c= 28.323(3) Å, = 104.639(4)°, Z = 4. The structure exhibits intra- and intermolecular hydrogen bonding of the type N–HO, C–HO, and N–HN. The molecules are interlinked through hydrogen bonds forming an infinite chain. This polymeric-like structure may play an important role in biological activity.