The molecular structure of a three-coordinate palladium(II)-styrene complex [Pd(η5-C5H5)(PEt3)(styrene)]BF4

The molecular structure of a three-coordinate palladium(II)-styrene complex, [Pd(η⁵-C₅H₅)(PEt₃)(styrene)]BF₄ has been determined by means of X-ray diffraction. The crystal belongs to the monoclinic system, space group P2₁/c, with four formula units in a cell of dimensions: a 10.229(3), b 11.262(3), c 18.760(5) Å and β 103.77(2)°. The structure was solved by the heavy atom method, and refined by the least-squares procedure to R = 0.050 for 3635 observed reflections. The palladium atom is surrounded by the cyclopentadienyl group, the triethylphosphine ligand and the olefinic bond of styrene in the cationic complex. In the palladiumstyrene bonding, the olefinic bond is inclined by 77.3° to the coordination plane defined by the Pd and P atoms and the center of the cyclopentadienyl ring (PdC(1) 2.176(6), PdC(2) 2.234(5) and C(1)C(2) 1.369(8) Å).     

The crystal and molecular structure of bis(pentamethylcyclopentadienyl)dichlorotitanium(IV)

The structure of bis(pentamethylcyclopentadienyl)dichlorotitanium(IV) has been investigated by single-crystal X-ray diffraction techniques. [η-C₅(CH₃)₅]₂TiCl₂ crystallizes in the orthorhombic space group P2₁2₁2₁ with cell dimensions a = 10.816(1), b = 8.132(1), c = 22.259(1) Å; Z = 4. Full matrix, least-squares refinement converged to a final R index of 0.032 based on 1429 reflections. The configuration about the titanium atom is a distorted tetrahedron comprised of the two chlorine atoms and the centroids of the two η-cyclopentadienyl rings. Several ring methyl groups are bent considerably out of the cyclopentadienyl plane and away from the titanium atom. These out-of-plane deviations are attributable to chlorine—methyl crowding and methyl—methyl contacts between the two rings.     

Crytal and molecular structure of hydrido(trichlorostannyl)bis-cyclopentadienyl molybdenum(η5-C5H5)2Mo(H)SnCl3

On the basis of X-ray analysis the crystal and molecular structures of (η₅-C₅H₅)₂Mo(H)SnCl₃ have been determined. The compound crystallizes in the monoclinic system with parameters: a = 8.313(3), b = 13.109(4), c = 6.384(2) Å, β = 106.52(2)°, space group P2₁/m, R = 0.028. The conformation occurring in Cp₂Mo(H)SnCl₃ is that with the maximum repulsion between the chloride atoms and the cyclopentadienyl rings. The hydride H atom is shielded by the cyclopentadienyl groups and chlorine atoms, which accounts for the compound's stability to oxygen and hydrolysis.     

Sensitized photoreduction of cobalt(II) and iron(II). Structural characterization of [Co(CO)(o-C6H4[PPh2]2)2]PF6

Triplet-state ketones readily sensitized the photoreduction of bis(acetyl-acetonato)cobalt(II) or CO_solv²⁺ under atmospheric pressure of carbon monoxide to give Co(CO)₄⁻. The low-valent cobalt could be trapped and isolated as phosphine-substituted metal carbonyl complexes. The crystal structure of one of the products, [Co(CO)(o-C₆H₄[PPh₂]₂)₂]PF₆ has been determined. It is orthorhombic, space group Pbca, Z = 8, with unit cell dimensions a 19.704(5), b 24.850(13), c 21.865(9) Å. Phosphine-substituted iron(0) carbonyl complexes have also been isolated from similar photoreductions of iron(II) species.     

Synthesis, spectroscopy, and magnetic characterization of copper(II) and cobalt(II) complexes with 2-amino-5-bromopyridine as ligand

The synthesis, spectroscopic, and magnetic characterization of two new copper(II) and cobalt(II) complexes are described. Both two compounds have the general formula [M(L)₂(Cl)₂] (M = Cu (I), Co (II); L = 2-amino-5-bromopyridine). These complexes were prepared in one-step synthesis and characterized by elemental analysis, FT-IR, UV-Vis, and EPR spectroscopy. Moreover, the single crystal structure of complex I was studied by the X-ray diffraction method. This compound consists of mononuclear units consisting of two ligands linked to metal via the nitrogen of pyridine ring. The UV-Vis spectra of copper(II) and cobalt(II) complexes show three and five absorption bands, respectively, attributed to the d-d transition of the metal ion, ligand → metal charge transfer and π → π* or n → π* transitions of the ligand. The FT-IR spectra show MN₂Cl₂ vibrations at 500–300 cm^?1. The complexes show room temperature magnetic moments of 1.78 and 4.12 μ_B for Cu(II) and Co(II), respectively. The X-band electron spin resonance (ESR) spectra of Cu(II) complex in DMF or DMSO frozen at liquid nitrogen temperature show the typical ΔM_S = ±1 transition.     

Single crystal circular and linear dichroism spectra and absolute configuration of M(en)3(NO3)2 (M = Zn(II), Cu(II), Ni(II), Co(II), Mn(II) and Ru(II)

The isomorphous single crystals of M(ethylenediamine)₃(NO₃)₂, where M is Zn(II), Ni(II) and Co(II), exhibit macroscopic optical activity as predicted by their acentric space group. Axial circular dichroism measurements on these pure crystals show conclusively that spontaneous resolution has occurred. The axial circular dichroism and orthoaxial linear dichroism spectra of these pure crystals, and of Cu(II), Ni(II), Co(II), Mn(II) and Ru(II) doped into the Zn(en)₃(NO₃)₂ crystal have been measured at ambient and cryogenic temperatures in the range from 7 to 35 kK. The first NO₃^? transition at 32.5 kK is assigned as ¹A ← ¹A based on its linear polarization and sign of rotational strength. The d-d transitions are assigned in the context of D₃ symmetry and reveal a small negative crystal field parameter k, consistent with theoretical prediction. A positive R for all d-d transitions is found to be associated with the Λ configuration for all of the complex ions, by correlation with the crystal and solution circular dichroism of Ru(en)₃²⁺.     

Oxidative addition reactions of dicyclopentadienyltin(II) and of tin(II) bis(acetylacetonate) with organic halides. The preparation of compounds of the type RSn(acac)2X

Oxidative addition reactions of tin(II) bis(acetylacetonate) with organic halides provide a route to new monoorganotin(IV) bis(acetylacetonate) halides. Dicyclopentadienyltin(II) undergoes oxidative addition with methyl iodide, diiodomethane and ethyl bromoacetate, but with allyl bromide, benzyl bromide and triphenylmethyl bromide carbon—carbon coupling reactions and the formation of the corresponding cyclopentadienyltin(II) halide take place. Some of the reactions are accelerated by light. NMR spectroscopic data show that the RSn(acac)₂X compounds have a cis-configuration. The compounds YCH₂Sn(acac)₂X (e.g. Y = I, CHCH₂, COOEt) provide the first examples of diastereo-topic non-equivalence of methylene protons in organotin compounds containing a hexacoordinate chiral tin centre.     

The two-dimensional band structure of (polyphthalocyaninato)Ni(II)

The two-dimensional (2D) band structure of (polyphthalocyaninato)Ni(II), Ni(ppc), has been analyzed by a self-consistent field (SCF ) Hartree–Fock (HF ) crystal orbital (CO ) formalism based on an INDO (intermediate neglect of differential overlap) type Hamiltonian. The calculated HF band gap of Ni(ppc) amounts to 0.24 eV. The highest filled band is a ringlike a_1u combination (D_4h symmetry label) localized at the carbon sites of the organic fragment. Remarkable hybridization in the valence band leads to the considerable band width Δ?_v of 2.92 eV. This value is close to the Δ?_v numbers which are conventionally encountered in one-dimensional metallomacrocycles. The effective width of the states in Ni(ppc) is 13.8 eV. In graphite a net π interval of 13.0 eV is predicted by the present CO formalism; i.e., the energetic distribution of the π electrons is roughly comparable in both 2D solids. The Ni 3d states in Ni(ppc) are far below the Fermi level which is calculated at ?4.9 eV; they are predicted between ?12.2 and ?16.4 eV in the mean-field approximation. Quasi-particle corrections lead to a significant shift of these strongly metal-centered states. Important electronic structure properties of Ni(ppc) are compared with those of 1D metallomacrocycles with similar molecular stoichiometry. The total density of states distribution of Ni(ppc) has been fragmented into projected (ligand π and σ, Ni 3d) contributions in order to allow for a transparent interpretation of the 2D band structure.     

Synthesis, characterization, crystal structure and antitumor activities of a novel demethylcantharidato bridged copper(II) phenanthroline complex

A new polymeric demethylcantharidato (DCA) bridged copper(Ⅱ) phenanthroline (phen) complex ([Cu(DCA)(phen)] n ·nH2O) has been synthesized and characterized by elemental analysis, IR and electronic spectra studies, molar conductivity measurement, and single crystal X-ray diffraction. The complex crystallizes in the orthorhombic space group Pbca with crystallographic data: a = 12.4537(4), b = 9.3897(5), c = 30.1264(10), and Z = 8. In the crystal structure, the octahedral coordinated copper(Ⅱ) ions are bridged by demethylcantharidate ligands into a one-dimensional zigzag-like structure with the Cu···Cu separation of 6.1719, along with phen ligands attached to both sides of the chain alternatively. Interdigitation of the chelating phen ligands of two neighboring chains via hydrophobic interaction and van der Waals forces along ac plane forms two-dimensional polymeric bilayers with discrete water sandwich layer between the adjacent polymeric bilayers. The evaluation of the cytotoxic activity of the copper(Ⅱ) complex against HCT-8 (colorectal carcinoma), A549 (pulmonary carcinoma), HeLa (cervical cancer), HepG2 (hepatocarcinoma), BGC-823 (gastric carcinoma), and MCF-7 (breast adenocarcinoma) cell lines revealed that it is a potent cytotoxic agent, superior to Na2DCA and phen against HeLa, HepG2 and BGC-823 cells.     

Synthesis, structures, and antimicrobial activity of nickel(II) and Zinc(II) complexes with 5-methoxy-2-[(3-methylaminopropylimino)methyl]phenol

The Schiff base 5-methoxy-2-[(3-methylaminopropylimino)methyl]phenol (MMP) derived from 4-methoxysalicylaldehyde and N-methylpropane-1,3-diamine and its nickel(II) and zinc(II) complexes [Ni(MMP)₂(NCS)₂] (I) and [ZnCl₂(MMP)] (II), have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The crystal of I is monoclinic: space group P2₁/c, a = 9.0488(8), b = 12.7768(12), c = 12.9232(11) Å, β = 101.927(5)°, V = 1461.9(2) ų, Z = 2. The crystal of II is orthorhombic: space group Pbca, a = 11.6991(7), b = 13.2839(8), c = 20.4451(12) Å, V = 3177.4(3) ų, Z = 8. The Schiff base coordinates to the metal atoms through the phenolate O and imine N atoms. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.     

Synthesis, structures, and antimicrobial activity of nickel(II) and zinc(II) complexes with Schiff bases derived from 3-bromosalicylaldehyde

The Schiff bases 2-bromo-6-[(3-cyclohexylaminopropylimino)methyl]phenol (HCMP) and 2-bromo-6-[(3-dimethylaminopropylimino)methyl]phenol (HDMP) derived from 3-bromosalicylaldehyde with N-cyclohexylpropane-1,3-diamine and N,N-dimethylpropane-1,3-diamine, respectively, and their nickel(II) and zinc(II) complexes [Ni(CMP)₂] (I) and [ZnCl₂(HDMP)] (II) have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The crystal of I is monoclinic: space group P2₁/c, a = 12.0304(6), b = 13.1594(6), c = 10.2445(5) Å, β = 101.019(1)°, V = 1591.9(1) ų, Z = 2. The crystal of II is monoclinic: space group C2/c, a = 22.286(5), b = 12.210(3), c = 14.513(3) Å, β = 124.118(3)°, V = 3269.5(13) ų, Z = 8. The Schiff base HCMP coordinates to the Ni atom through the phenolate O, imine N, and amine N atoms, while the Schiff base HDMP coordinates to the Zn atom through the phenolate O and imine N atoms. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.     

Paramagnetic carbonyl cobalt(II) complexes. Molecular structure of bromocarbonyl-1,1,1-tris(diphenylphosphinomethyl)ethanecobalt(II) tetraphenylborate

Carbon monoxide or cyclohexyl isonitrile (L) react with the dinuclear five-coordinated derivatives of 1,1,1-tris(diphenylphosphinomethyl)ethane, (triphos), [(triphos)Co(μ-X)₂Co(triphos)](BPh₄)₂ (X = halide) to give complexes of formula [(triphos)Co(L)X]BPh₄. The latter are rare examples of paramagnetic cobalt(II) carbonyl complexes. The molecular structure of [(triphos)Co(CO)Br]BPh₄ has been determined from counter diffraction data. The crystals are monoclinic, space group P2₁/a with cell dimensions a 20.225(8), b 20.664(9), c 13.301(5); β 97.24(5)°, D_c = 1.338 g cm^?3 for Z = 4. Full-matrix least squares refinement led to the conventional R factor of 0.057 for 3648 observed reflections. The molecular structure consists of five-coordinate [(triphos)Co(CO)Br]⁺ cations of intermediate geometry and BPh^?₄ anions.     

Contribution to the crystal chemistry of tetrametaphosphates(II)

Chemical preparations and crystal structures of two hydrated forms of CsNa₃P₄O₁₂ are described. CsNa₃P₄O₁₂ · 4H₂O with a = 14.50(2), b = 7.804(3), c = 7.006(3)Å crystallizes in space group Imm2, Z = 2. The crystal structure has been determined using 745 independent reflexions with a final R value of 0.028 (R = 0.040 with the 934 collected reflexions), CsNa₃P₄O₁₂ · 3H₂O with a = 11.39(1), b = 10.92(1), c = 11.81(1)Å, β = 95.24(5)° in $\text{P2}{}_1\text{c}\text{, Z = 4}$. The crystal structure has been solved with 2975 independent reflexions with a final R-value of 0.018 (R = 0.057 with all the 6531 collected reflexions). In both structures there are four-membered rings built up with corner-sharing phosphate tetrahedron. For the tetrahydrate, the ring symmetry is mm whereas in the trihydrate, one observes two independent ring anions of symmetry $\text{1}$. In both cases hydrogen atoms have been located and refined.     

Synthesis and crystal structure of divaleratobis(nicotinamide)copper(II)

A copper(II) valerate complex with nicotinamide (L) [CuL₂(C₄H₉COO)₂] (I) has been synthesized and studied by IR spectroscopy and thermogravimetry. The crystal structure has been determined. The crystals of 1 are monoclinic, a = 11.297(1) Å, b = 6.666(1) Å, c = 16.873(2) Å, b = 108.50(1)°, V = 1204.9(3) ų, Z = 2, space group P2₁/c. The structural units of the crystal of I are centrosymmetric tetragonal bipyramidal (4+2) complex molecules. The equatorial positions of the bipyramid are occupied by trans-arranged pairs of O (Cu-O, 1.973 Å) and N (Cu-N, 2.006 Å) atoms, and the axial positions are occupied by the second O atoms of the valerate anions located at longer distances (Cu-O, 2.506 Å). The supramolecular associates formed in the crystal are layers of hydrogen-bonded complexes. The disordered hydrocarbon “tails” of the valerate groups point toward the interlayer space.     

A novel water-rich mononuclear copper(II) complex with pyridine-2,4-dicarboxylate: Synthesis and crystal structure

A new monomolecular copper(II) complex, [Cu(Phen)₂(Pda)] · 9H₂O (I) (H₂Pda = pyridine-2,4-dicarboxylate acid, Phen = 1,10-phenanthroline), has been prepared from H₂Pda and Phen at room temperature and characterized by IR, elemental analysis, X-ray powder diffraction, and single-crystal X-ray diffraction. Structure analysis shows that each Cu(II) is coordinated by two Phen ligands and one Pda ligand to complete a octahedron CuN₅O chromophore. In addition, a unique water networks paralleling to (001) composed by the crystallization water through hydrogen bonds play a important role in the stability of crystal structure. The crystal structure is found to be orthorombic with space group Pbcn and cell parameters a = 13.651(4), b = 22.516(7), c = 22.386(7) Å, R ₁ = 0.0735 and wR ₂ = 0. 0.1935.     

Organolanthanoids V. The crystal and molecular structure of DI-η5-cyclopentadienyl-1,2-dimethoxyethaneytterbium(II)

Crystals of di-η⁵-cyclopentadienyl-1,2-dimethoxyethaneytterbium(II) are mono-clinic, space group Cc, with a 9.25(2), b 23.49(5), c 8.23(2) Å, β 123.59(4)° and Z  4. The ytterbium ion is pseudo-tetrahedrally coordinated by two cyclopentadienyl groups and a bidentate 1,2-dimethoxyethane ligand, and there is no inter-molecular association. The sites of the cyclopentadienyl ligands are disordered.     

Copper(II) and lead(II) complexes based on 2,3,5,6-tetrakis(2-pyridyl)pyrazine as a polydentate ligand

The Cu(II) complexes [Cu(Tppz)(Dipic)] · 8H₂O (I) and [Pb₂(Tppz)Cl₄] _n (II), where Tppz, H2Dipic are 2,3,5,6-tetrakis(2-pyridyl)pyrazine, dipicolinic acid, respectively, have been synthesized and characterized by elemental analyses, IR, cyclic voltammetry, and electronic spectral studies. Solid state structures of both complexes have been determined by single crystal X-ray crystallography. An ORTEP drawing of two complexes shows that the coordination geometry around the metal center is a distorted octahedron. There are extensive conventional intermolecular O-H…O, N-H…O, and weaker C-H…O and C-H…Cl non-classical hydrogen bonds, which cause the stability of the crystal structure. Crystal data for I: monoclinic, space group: C2/c, a = 35.421(3), b = 8.422(6), c = 22.824(8) Å, β = 101.69(2)°, V = 6668(5) ų, Z = 8. Crystal data for II: triclinic, space group P \(\bar 1\) , a = 7.9534(4), b = 8.8682(5), c = 9.4245(5) Å, β = 95.086(2)°, V = 655.93(6) ų, Z = 2.     

The crystal and molecular structure of 1-bromobenzocymantrene, (η5-C9H6Br)Mn(CO)3

The crystal and molecular structure of tricarbonyl [1–4: 9-η-(1-bromo)indenyl]manganese (III) prepared by reaction of bromo(pentacarbonyl)manganese (II) with diazoindene (I) (“diazo method”) has been determined by X-ray diffraction methods. III belongs to the monoclinic space group P2₁/c with unit cell constants a 12.953(9), b 7.627(5), c 13.098(9) Å, and β 110.53(5)°. Full-matrix least-squares refinement converged with a conventional R factor of 0.052 based on 1505 observed reflections. The molecule contains an essentially planar indenyl-π-ligand which is coordinated to the manganese atom through its cyclopentadienyl-like moiety. The bromine ligand is attached to the C(1) position of the indenyl system and has only a very slight influence on the characteristics of the indenyl skeleton. The change from cyclopentadienyl (in cymantrene) to indenyl (in III) produces essentially no disturbance in the normal manganese—carbonyl linkage.     

Evidence for the predominance of trigonal pyramidal environments in tin(II) chemistry: The crystal structure of potassium (hydrogen(bismaleato))stannate(II)

The crystal structure of potassium (hydrogen(bismaleato))stannate(II) is reported. It has unit cell data a = 7.361(12), b = 12.305(3), c = 7.246(8) Å, α = 97.02(6)°, β = 109.83(28)°, γ = 87.48(7)°, U = 612.77 ų, Z = 2, D_c = 2.096 g cm^?3, D_m = 2.093 g cm ^?3 and triclinic space group P$\text{1}$. The structure consists of layers of discrete [Sn(CHCO₂: CHCO₂)(CHCO₂: CHCO₂H)]₂^2? moieties with potassium ions located in holes between the layers. In the discrete unit are two different maleate groups, an anisobidentate maleate ligand and a terminal unidentate monoprotomaleate ligand. The tin atom lies in a trigonal pyramidal environment with three SnO distances, to the maleate and monoprotomaleate ligands, of 2.199 and 2.212 Å respectively. These bonds lengths are consistent with the ¹¹⁹Sn Mössbauer data. The preference for tin to exist in a trigonal pyramidal environment, even in the presence of potential chelating ligands is clearly shown in the structure of this complex tin(II) maleate.     

Zur Struktur der basischen Diquecksilber(I)-nitrate. II. Kristallstruktur des Hg10(OH)4(NO3)6

Crystal Structure of the Basic Dimercury(I) Nitrates. II. Crystal Structure of Hg₁₀(OH)₄(NO₃)₆ . The crystal structure of Hg₁₀(OH)₄(NO₃)₆ has been determined from single crystal x-ray diffraction data. The unit cell is triclinic, space group P1 , a = 999.4(5), b = 909.9(5), c = 765.9(2) pm, α = 85.98(4), β = 78.70(3), γ = 109.83(5)°; Z = 1, R = 6.2%, R_w = 8.2%. Finite cationic chains [(Hg₂)₅(OH)₄(NO₃)₂]⁴⁺ are joined together by weak van der Waals-type interactions between neighbouring Hg and O atoms, thus forming ribbons running along [100]. The coordination sphere of the Hg atoms is completed by further nitrate ions, which lead to the formation of a loose framework. Thereby the metal atoms are not surrounded by simple coordination polyhedra.