Pulsed-field ionization electron spectroscopy of group 6 metal (Cr, Mo, and W) bis(benzene) sandwich complexes

Group 6 metal bis(benzene) sandwich complexes (M-bz(2): M=Cr, Mo, and W and bz=C(6)H(6)) were produced with laser vaporization molecular beam techniques and studied by pulsed-field ionization zero electron kinetic energy spectroscopy and density functional theory calculations. Each sandwich complex is in a D(6h) eclipsed configuration with (1)A(1g) and (2)A(1g) as the neutral and cationic ground electronic states, respectively. The adiabatic ionization energies for Cr-, Mo-, and W-bz(2) are measured to be 44,081(7), 44,581(10), and 43,634(7) cm(-1), respectively. The metal-benzene stretch and benzene torsion frequencies of the ion are measured to be 264, 277, and 370 cm(-1) and 11, 21, and 45 cm(-1) for Cr-, Mo-, and W-bz(2), respectively. In addition, a C-H out-of-plane bending mode is measured to be 787 cm(-1) for the Cr(+)-bz(2) complex, while a C-C in-plane bending mode is measured to be 614 cm(-1) for the W(+)-bz(2) complex. The unusual trend in the ionization energy and metal-benzene stretch frequency indicates strong relativistic effects on tungsten binding.     

Synthesis and Crystal Structure of Dichlorobis[N-（4-hydroxylsalicylidene）-3-dimethylaminopropylamine]Ni（II）

1 INTRODUCTION The chemistry of nickel complex with multi- dentate Schiff base ligands has attracted particular attention because this metal can exhibit several oxi- dation states[1]. Such complexes with different oxi- dation states play an important role in bioinorganic chemistry and redox enzyme systems[2], and many of them can provide the basis of models for active sites of biological systems or act as catalysts[3]. Nickel complexes with tetradentate N2O2 and tri- dentate N2O Schi…     

NiN(2)S(2) complexes as metallodithiolate ligands to Rh(I), Rh(II) and Rh(III)

Three molecular structures are reported which utilize the NiN(2)S(2) ligands -, (bis(mercaptoethyl)diazacyclooctane)nickel and -', bis(mercaptoethyl)diazacycloheptane)nickel, as metallodithiolate ligands to rhodium in oxidation states i, ii and iii. For the Rh(I) complex, the NiN(2)S(2) unit behaves as a bidentate ligand to a square planar Rh(I)(CO)(PPh(3))(+) moiety with a hinge or dihedral angle (defined as the intersection of NiN(2)S(2) and S(2)Rh(C)(P) planes) of 115 degrees . Supported by -' ligands, the Rh(II) oxidation state occurs in a dirhodium C(4) paddlewheel complex wherein four NiN(2)S(2) units serve as bidentate bridging ligands to two singly-bonded Rh(II) ions at 2.893(8) A apart. A compilation of the remarkable range of M-M distances in paddlewheel complexes which use NiN(2)S(2) complexes as paddles is presented. The Rh(III) state is found as a tetrametallic [Rh(-')(3)](3+) cluster, roughly shaped like a boat propeller and structurally similar to tris(bipyridine)metal complexes.     

Coordination chemistry of amine bis(phenolate) cobalt(II), nickel(II), and copper(II) complexes

Cobalt(II), nickel(II), and copper(II) (1, 2, and 3) complexes of the dianionic form of the bis(phenolate) ligand N,N-bis(3,4-dimethyl-2-hydroxybenzyl)-N',N'-dimethylethylenediamine (H2L) have been synthesized by electrochemical oxidation of the appropriate metal in an acetonitrile solution of the ligand. When copper is used as the anode, the addition of 1,10-phenanthroline to the electrolytic phase gave rise to a different compound [CuL]2.2CH3CN (4). The compounds [CoL]2.2CH3CN (1), [Ni2L2(H2O)].H2O (2), [CuL]2.3H2O (3), and [CuL]2.2CH3CN (4) were characterized by microanalysis, IR, electronic spectroscopy, FAB mass spectrometry, magnetic measurements and by single-crystal X-ray diffraction. The crystal structures show that the complexes have a dinuclear structure. In compounds 1, 3, and 4, two metal ions are coordinated by the two amine nitrogens and the two phenol oxygen atoms of a deprotonated pendant phenol ligand, with one phenolic oxygen atom from ligand acting as a bridge. In compounds 1 and 3, each metal center has a geometry that is closest to trigonal bipyramidal. Magnetic susceptibility data for both compounds show an antiferromagnetic coupling with 2J = -15 cm(-1) for the cobalt(II) complex and a strong antiferromagnetic coupling with 2J = -654 cm(-1) for the copper(II) complex. However, in 4 the geometry around the metal is closer to square pyramidal and the compound shows a lower antiferromagnetic coupling (2J = -90 cm(-1)) than in 3. The nickel atoms in the dimeric compound 2 are hexacoordinate. The NiN2O4 chromophore has a highly distorted octahedral geometry. In this structure, a dianionic ligand binds to one nickel through the two amine nitrogen atoms and the two oxygen atoms and to an adjacent nickel via one of these oxygen atoms. The nickel atoms are linked through a triple oxygen bridge involving two phenolic oxygens, each from a different ligand, and an oxygen atom from a water molecule. The two nickel ions in 2 are ferromagnetically coupled with 2J = 19.8 cm(-1).     

Gas-phase rate coefficients for the reactions of nitrate radicals with (Z)-pent-2-ene, (E)-pent-2-ene, (Z)-hex-2-ene, (E)-hex-2-ene, (Z)-hex-3-ene, (E)-hex-3-ene and (E)-3-methylpent-2-ene at room temperature

Rate coefficients for reactions of nitrate radicals (NO3) with (Z)-pent-2-ene, (E)-pent-2-ene, (Z)-hex-2-ene, (E)-hex-2-ene, (Z)-hex-3-ene, (E)-hex-3-ene and (E)-3-methylpent-2-ene were determined to be (6.55 +/- 0.78)x 10(-13) cm3 molecule(-1) s(-1), (3.78 +/- 0.45)x 10(-13) cm3 molecule(-1) s(-1), (5.30 +/- 0.73)x 10(-13) cm(3) molecule(-1) s(-1), (3.83 +/- 0.47)x 10(-13) cm(3) molecule(-1) s(-1), (4.37 +/- 0.49)x 10(-13) cm(3) molecule(-1) s(-1), (3.61 +/- 0.40)x 10(-13) cm3 molecule(-1) s(-1) and (8.9 +/- 1.5)x 10(-12) cm3 molecule(-1) s(-1), respectively. We performed kinetic experiments at room temperature and atmospheric pressure using a relative-rate technique with GC-FID analysis. The experimental results demonstrate a surprisingly large cis-trans(Z-E) effect, particularly in the case of the pent-2-enes, where the ratio of rate coefficients is ca. 1.7. Rate coefficients are discussed in terms of electronic and steric influences, and our results give some insight into the effects of chain length and position of the double bond on the reaction of NO3 with unsaturated hydrocarbons. Atmospheric lifetimes were calculated with respect to important oxidants in the troposphere for the alkenes studied, and NO3-initiated oxidation is found to be the dominant degradation route for (Z)-pent-2-ene, (Z)-hex-3-ene and (E)-3-methylpent-2-ene.     

Electron-phonon interactions in charged cubic fluorocarbon cluster, (CF)8

Electron-phonon interactions in the charged cubic fluorocarbon, (CF)8 are studied, and compared with those in charged (CH)8 and (CD)8. The A1g mode of 1470 cm(-1) much more strongly couples to the a1g lowest unoccupied molecular orbitals (LUMO) than the A1g mode of 554 cm(-1) in (CF)8. The T2g mode of 1030 cm(-1), the Eg mode of 980 cm(-1), and the A1g mode of 1470 cm(-1) strongly couple to the t2u highest occupied molecular orbitals (HOMO) in (CF)8. The total electron-phonon coupling constants for the monoanion (l(-1)) and monocation (l(+1)) of (CF)8 are estimated to be 0.932 and 0.585 eV, respectively. The logarithmically averaged phonon frequencies for the monoanion (omega(ln,-1)) and monocation (omega(ln,+1)) of (CF)8 are estimated to be 1365 and 998 cm(-1), respectively. The l(-1) and omega(ln,-1) values increase much more significantly by H-F substitution than by H-D substitution in cubane. The larger displacements of carbon atoms in the high frequency vibronic active mode in (CF)8 than those in (CD)8 due to larger atomic mass of fluorine than that of deuterium, and the unchanged electron distributions in the LUMO somewhat localized on carbon atoms as a consequence of H-F and H-D substitution in cubane, are the main reason why the l(-1) and omega(ln,-1) values increase much more significantly by H-F substitution than by H-D substitution. The l(+1) and omega(ln,+1) values less significantly change than the l(-1) and omega(ln,-1) values by H-F substitution as well as by H-D substitution in cubane. This is because the t2u HOMO in (CF)8 and the t2g HOMO in (CH)8 are somewhat localized on fluorine atoms, and thus, the high frequency vibronic active modes in which the displacements of carbon atoms are large cannot necessarily very strongly couple to the HOMO somewhat localized on fluorine atoms in (CF)8.     

Synthesis of s-fac/mer bis(N2-methyldiethylenetriamine,L) nickel(II): X-ray single crystal structures of s-fac[NiL2](NO3)2 and mer[NiL2](CF3CO2)2

[NiL2](NO3)2 (1) and [NiL2](CF3CO2)2 (2) (L = N2-methyldiethylenetriamine] have been synthesized and their X-ray single crystal structures have been determined. The triamines are ligated to NiII s-facially in (1) and meridionally in (2), with a NiN6 chromophore in each complex.     

The Al+ -H(2) cation complex: rotationally resolved infrared spectrum, potential energy surface, and rovibrational calculations

The infrared spectrum of the Al(+)-H(2) complex is recorded in the H-H stretch region (4075-4110 cm(-1)) by monitoring Al(+) photofragments. The H-H stretch band is centered at 4095.2 cm(-1), a shift of -66.0 cm(-1) from the Q(1)(0) transition of the free H(2) molecule. Altogether, 47 rovibrational transitions belonging to the parallel K(a)=0-0 and 1-1 subbands were identified and fitted using a Watson A-reduced Hamiltonian, yielding effective spectroscopic constants. The results suggest that Al(+)-H(2) has a T-shaped equilibrium configuration with the Al(+) ion attached to a slightly perturbed H(2) molecule, but that large-amplitude intermolecular vibrational motions significantly influence the rotational constants derived from an asymmetric rotor analysis. The vibrationally averaged intermolecular separation in the ground vibrational state is estimated as 3.03 A, decreasing by 0.03 A when the H(2) subunit is vibrationally excited. A three-dimensional potential energy surface for Al(+)-H(2) is calculated ab initio using the coupled cluster CCSD(T) method and employed for variational calculations of the rovibrational energy levels and wave functions. Effective dissociation energies for Al(+)-H(2)(para) and Al(+)-H(2)(ortho) are predicted, respectively, to be 469.4 and 506.4 cm(-1), in good agreement with previous measurements. The calculations reproduce the experimental H-H stretch frequency to within 3.75 cm(-1), and the calculated B and C rotational constants to within approximately 2%. Agreement between experiment and theory supports both the accuracy of the ab initio potential energy surface and the interpretation of the measured spectrum.     

Synthesis, structure, and magnetic ordering of layered (2-D) V-based tris(oxalato)metalates

The reaction of K3[M(III)(ox)3].3H2O [M = V (1), Cr; ox = oxalate], Mn(II)/V(II), and [N(n-Bu)4]Br in water leads to the isolation of 2-D V-based coordination polymers, [[N(n-Bu)4][Mn(II)V(III)(ox)3]]n (2), [[N(n-Bu)4][V(II)Cr(III)(ox)3]]n (3), [[N(n-Bu)4][V(II)V(III)(ox)3]]n (4), and an intermediate in the formation of 4, [[N(n-Bu)4][V(II)V(III)(ox)3(H2O)2]]n.2.5H2O (4a), while 1-D [V(II)(ox)(H2O)2]n (5) is obtained by using Na2ox and [V(OH2)6]SO4 in water. The structures of 1-5 have been investigated by single crystal and/or powder X-ray crystallography. In 1, V(III) is coordinated with three oxalate dianions as an approximately D3 symmetric, trigonally distorted octahedron. 1 is paramagnetic [mu(eff) = 2.68 mu(B) at 300 K, D = 3.84 cm(-1) (D/k(B) = 5.53 K), theta = -1.11 K, and g = 1.895], indicating an S = 1 ground state. 2 exhibits intralayer ferromagnetic coupling below 20 K, but does not magnetically order above 2 K, and 3 shows a strong antiferromagnetic interaction between V(II), S = 3/2 and Cr(III), S = 3/2 ions (theta = -116 K) within the 2-D layers. 4 and 4a magnetically order as ferrimagnets at T(c)'s, taken as the onset of magnetization, of 11 and 30 K, respectively. The 2 K remanent magnetizations are 2440 and 2230 emu.Oe mol(-1) and the coercive fields are 1460 and 4060 Oe for 4 and 4a, respectively. Both 4 and 4a clearly show frequency dependence, indicative of spin-glass-like behavior. The glass transition temperatures were at 6.3 and 27 K, respectively, for 4 and 4a. 1-D 5 exhibits antiferromagnetic coupling of -4.94 cm(-1) (H = -2Jsigma(i=1)n.S(i-1) - gmu(B)sigma(i=0)(n)H.S(i)) between the V(II) ions.     

Single-molecule magnets: structural characterization, magnetic properties, and (19)F NMR spectroscopy of a Mn(12) family spanning three oxidation levels

The syntheses, crystal structures, and magnetic properties of [Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)] (2), (NMe(4))[Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)] (3), and (NMe(4))(2)[Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)] (4) are reported. Complex 2 displays quasi-reversible redox couples when examined by cyclic voltammetry in CH(2)Cl(2): one-electron reductions are observed at 0.64 and 0.30 V vs ferrocene. The reaction of complex 2 with 1 and 2 equiv of NMe(4)I yields the one- and two-electron reduced analogues, 3 and 4, respectively. Complexes 2.3CH(2)Cl(2), 3.4.5CH(2)Cl(2).(1)/(2)H(2)O, and 4.6C(7)H(8) crystallize in the triclinic P, monoclinic P2/c, and monoclinic C2/c space groups, respectively. The molecular structures are all very similar, consisting of a central [Mn(IV)O(4)] cubane surrounded by a nonplanar alternating ring of eight Mn and eight mu(3)-O(2)(-) ions. Peripheral ligation is provided by 16 bridging C(6)F(5)CO(2)(-) and 4 H(2)O ligands. Bond valence sum calculations establish that the added electrons in 3 and 4 are localized on former Mn(III) ions giving trapped-valence Mn(IV)(4)Mn(III)(7)Mn(II) and Mn(IV)(4)Mn(III)(6)Mn(II)(2) anions, respectively. (19)F NMR spectroscopy in CD(2)Cl(2) shows retention of the solid-state structure upon dissolution and detrapping of the added electrons in 3 and 4 among the outer ring of Mn ions on the (19)F NMR time scale. DC studies on dried microcrystalline samples of 2, 3, and 4.2.5C(7)H(8) restrained in eicosane in the 1.80-10.0 K and 1-70 kG ranges were fit to give S = 10, D = -0.40 cm(-)(1), g = 1.87, D/g = 0.21 cm(-)(1) for 2, S = 19/2, D = -0.34 cm(-)(1), g = 2.04, D/g = 0.17 cm(-)(1) for 3, and S = 10, D = -0.29 cm(-)(1), g = 2.05, D/g = 0.14 cm(-)(1) for 4, where D is the axial zero-field splitting parameter. The clusters exhibit out-of-phase AC susceptibility signals (chi(M)' ') indicative of slow magnetization relaxation in the 6-8 K range for 2, 4-6 K range for 3, and 2-4 K range for 4; the shift to lower temperatures reflects the decreasing magnetic anisotropy upon successive reduction and, hence, the decreasing energy barrier to magnetization relaxation. Relaxation rate vs T data obtained from chi(M)' ' vs AC oscillation frequency studies down to 1.8 K were combined with rate vs T data from DC magnetization decay vs time measurements at lower temperatures to generate an Arrhenius plot from which the effective barrier (U(eff)) to magnetization reversal was obtained; the U(eff) values are 59 K for 2, 49 and 21 K for the slower- and faster-relaxing species of 3, respectively, and 25 K for 4. Hysteresis loops obtained from single-crystal magnetization vs DC field scans are typical of single-molecule magnets with the coercivities increasing with decreasing T and increasing field sweep rate and containing steps caused by the quantum tunneling of magnetization (QTM). The step separations gave D/g values of 0.22 cm(-)(1) for 2, 0.15 and 0.042 cm(-)(1) for the slower- and faster-relaxing species of 3, and 0.15 cm(-)(1) for 4.     

Reactivity of the Ni-->B dative sigma-bond in the nickel boratrane compounds [kappa4-B(mimBut)3]NiX (X=Cl, OAc, NCS, N3): synthesis of a series of B-functionalized tris(2-mercapto-1-tert-butylimidazolyl)borato complexes, [YTmBut)]NiZ

The nickel boratrane complexes [kappa4-B(mimBut))3]Ni(kappa1-OAc), [kappa4-B(mimBut)3]NiNCS and [kappa4-B(mimBut)3]NiN3 are obtained via metathesis of the chloride ligand of [kappa4-B(mimBut)3]NiCl with TlOAc, KSCN and NaN3, respectively; the Ni-->B bond in these complexes is a site of reactivity, thereby providing a means of synthesizing nickel complexes that feature B-functionalized tris(mercaptoimidazolyl)borate derivatives, [YTmBut]NiZ.     

Influence of the Peripheral Ligand Atoms on the Exchange Interaction in Oxalato-Bridged Nickel(II) Complexes: An Orbital Model. Crystal Structures and Magnetic Properties of (H(3)dien)(2)[Ni(2)(ox)(5)].12H(2)O and [Ni(2)(dien)(2)(H(2)O)(2)(ox)]Cl(2)

Two nickel(II) complexes of formula (H(3)dien)(2)[Ni(2)(ox)(5)].12H(2)O (1) and [Ni(2)(dien)(2)(H(2)O)(2)(ox)]Cl(2) (2) (dien = diethylenetriamine and ox = oxalate dianion) have been synthesized and characterized by single-crystal X-ray diffraction. 1 crystallizes in the orthorhombic system, space group Abnn, with a = 15.386(4) ?, b = 15.710(4) ?, c = 17.071(4) ?, and Z = 4. 2 crystallizes in the monoclinic system, space group P2(1)/c, with a = 10.579(1) ?, b = 7.258(1) ?, c = 13.326(1) ?, beta = 93.52(3) degrees, and Z = 2. The structures of 1 and 2 consist of dinuclear oxalato-bridged nickel(II) units which contain bidentate oxalate (1) and tridentate dien in the fac-conformation (2) as terminal ligands. Both features, oxalato as a peripheral ligand and dien in the fac-conformation (instead of its usual mer-conformation), are unprecedented in the coordination chemistry of nickel(II). The nickel atom is six-coordinated in both compounds, the chromophores being NiO(6) (1) and NiN(3)O(3) (2). The Ni-O(ox) bond distances at the bridge (2.072(4) ? in 1 and 2.11(1) and 2.125(9) ? in 2) are somewhat longer than those concerning the terminal oxalate (2.037(5) and 2.035(3) ? in 1). Magnetic susceptibility data of 1 and 2 in the temperature range 4.2-300 K show the occurrence of intramolecular antiferromagnetic coupling with J = -22.8 (1) and -28.8 (2) cm(-)(1) (J being the parameter of the exchange Hamiltonian H = -JS(A).S(B)). The observed value of -J in the investigated oxalato-bridged nickel(II) complexes, which can vary from 22 to 39 cm(-)(1), is strongly dependent on the nature of the donor atoms from the peripheral ligands. This influence has been analyzed and rationalized through extended Hückel calculations.     

Crystal Structure of a Nickel(Ⅱ) Complex with Asymmetric L-Histidine Ligand

A novel nickel(Ⅱ) complex with L-histidine has been synthesized and solved by single-crystal X-ray diffraction analysis at physiological pH. The title complex (C7H16NiN4O6S, Mr= 343.01) crystallizes in monoclinic, space group P21 with a = 7.2194(7), b = 7.5968(7), c =12.2797(11) (A), β = 93.3110(10)°, V = 672.35(11) (A)3, Z = 2, Dc= 1.694 g/cm3, F(000) = 356,μ(MoKα) = 1.626 mm-1, T = 293(2) K, the final R = 0.0184 and wR = 0.0426 for 2207 observed reflections with I ＞ 2σ(Ⅰ). The complex provides insights into a possible structural arrangement between nickel (Ⅱ) and L-histidine which may be physiologically important and abundantly present in biological systems.     

Synthesis, structure, magnetism, and spectroscopic properties of heterobinuclear copper(II)-zinc(II) complexes and their copper(II)-copper(II) analogues in asymmetric ligand environments

Heterobinuclear copper(II)-zinc(II) complexes and their homobinuclear dicopper(II) counterparts (1-4) of two asymmetric ligands (H2L1 and H2L2), based on 2-aminocyclopent-1-ene-1-dithiocarboxylate, are reported. The ligands are capable of providing both donor set and coordination number asymmetry in tandem. Metal centers in these complexes are connected by a micro-alkoxo and a bridging pyrazolate moiety, as confirmed by X-ray structure analyses of 1, 3, and 4. The Cu(1) site in the dicopper complex (1) is square planar and so are the copper sites in the Cu-Zn complexes 3 and 4. The pentacoordinated Zn sites in the latter complexes have distorted TBP geometry (tau = 0.74), while the corresponding Cu site in 1 has a highly distorted square pyramidal structure (tau = 0.54). The Cu...Zn separations in 3 and 4 are 3.3782 and 3.3403 angstroms, respectively, while the Cu...Cu distance in 1 is 3.3687 angstroms. The dicopper complexes are EPR silent at 77 K, in which the copper(II) centers are coupled by strong antiferromagnetic coupling (J = ca. -290 cm(-1)) as confirmed by variable-temperature (4-300 K) magnetic measurements. These compounds (1 and 2) undergo two one-electron reductions and a single step two-electron oxidation at ca. -0.26, -1.40, and 1.0 V vs Ag/AgCl reference, respectively, as indicated by cyclic and differential pulse voltammetry done at subambient temperatures. EPR spectra of 3 and 4 display axial anisotropy at 77 K with the gperpendicular region being split into multiple lines due to N-superhyperfine coupling (AN = 15.3 x 10(-4) cm(-1)). The observed trend in the spin-Hamiltonian parameters, gparallel > gperpendicular > 2.04 and |Aperpendicular| < |Aparallel| approximately (120-150) x 10(-4) cm(-1), indicates a d(x2-y2)-based ground state with tetragonal site symmetry for the Cu(II) center in these molecules.     

Excited-state distortions determined from structured luminescence of nitridorhenium(V) complexes

The nitridorhenium(V) complexes ReNCl(2)(PCy3)(2) (1), ReNBr(2)(PCy3)(2) (2), ReNCl(2)(PPh3)(2) (3), and ReNBr(2)(PPh3)(2) (4) produce structured emission spectra upon excitation at low temperature. The origin, E(00), occurs at 15 775, 16 375, 15 875, and 16 300 cm(-1), respectively. The vibronic peaks are regularly spaced with an average energy separation corresponding to the Re triple bond N stretching frequency. The nitridorhenium stretching frequency ranges from 1095 to 1101 cm(-1), as determined by Raman and IR spectroscopy. The excited-state distortions are calculated by fitting the emission spectra. The excited state arises primarily from a d(xy) (ReN nonbonding) to d(yz) (ReN pi antibonding) transition. The rhenium-nitrogen bond length in the excited state is 0.08 A longer than in the ground electronic state, which is consistent with the difference in bond lengths of ReN bonds of bond order 3 and bond order 2.5 as determined from molecular structures.     

Two Nickel(Ⅱ) Complexes Constructed by Novel Bis(3-methoxy-2-pyridyl)ether-6,6"-dicarboxylic Acid Ligand: Lattice Water Control of Structure

Under given conditions, two complexes of [Ni(H2O)2BEDA]·2H2O 1 and [Ni(Py)2-sized and characterized by elemental analysis and X-ray single-crystal diffraction. Crystal data for 1:C14H18NiN2O11, monoclinic C2/c, a = 14.3844(17), b = 12.9900(15), c = 9.6309(11) (A°),β=104.3350(10)°, V = 1743.5(4) (A°)3, Z = 4, Dc= 1.711 g/cm3, F(000) = 928,μ= 1.179 mm-1, Mr=449.01, the final R = 0.0228 and wR = 0.0625. Crystal data for 2: C24H32NiN4O13, triclinic P1, a=9.423(2), b = 11.863(3), c = 13.089(3) (A°), α = 91.511(3), β= 92.465(3), γ = 100.696(2)°, V =1435.6(6) (A°)3, Z = 2, Dc= 1.488 g/cm3, F(000) = 672,μ= 0.748 mm-1, M,= 643.25, the final R =0.0400 and wR = 0.0975. Interestingly, in the two complexes, lattice water molecules dominate its crystal structures. Therefore, extensive intermolecular hydrogen bonds assemble 1 and 2 into 2D extended sheets and a 3D open framework, respectively. Furthermore, water molecules present in 2 are associated to form water clusters.     

Metal-metal bonded diruthenium(II, III) assemblies with the polycyano anionic linkers N(CN)2-, C(CN)3-, and 1,4-dicyanamido-2,5-dimethylbenzene (DM-dicyd2-): syntheses, structures, and magnetic properties

The new metal-metal bonded diruthenium(II,III) compounds [Ru2(O2CCH3)4(mu-L)]infinity (L = N(CN)2-, 1; C(CN)3-, 2) and [[Ru2(O2CCH3)2(mhp)2]2(mu-DM-Dicyd)] (3) (mhp = 2-oxy-6-methylpyridinate, DM-Dicyd = 1,4-dicyanamido-2,5-dimethylbenzene dianion) have been synthesized and fully characterized. Compounds 1 and 2 were synthesized by the reaction of [Ru2(O2CCH3)4(NCCH3)2](BF4) with NaN(CN)2 and KC(CN)3, respectively. The "dimer-of-dimers", 3, was synthesized by a 2:1 reaction of [Ru2(O2CCH3)2(mhp)2(MeOH)](BF4) with [As(Ph)4]2[DM-Dicyd]. Compound 1 crystallizes in the monoclinic space group C2/m with a = 10.174(2) A, b = 13.016(3) A, c = 7.0750(14) A, beta = 101.83(3) degrees, and Z = 2. Compound 2 crystallizes in the orthorhombic space group Fdd2 with a = 29.679(6) A, b = 31.409(6) A, c = 7.3660(15) A, V = 6866(2) A3, and Z = 16. In compound 1, dicyanamide anions (N(CN)2-) bridge the [Ru2(O2CCH3)4]+ units in an end-to-end bridging mode, thereby forming an alternating one-dimensional chain. In compound 2, two cyano groups of tricyanomethanide anion (C(CN)3-) are coordinated to independent [Ru2(O2CCH3)4]+ units to give a chain similar to that found in 1. The Ru-Ru bond distances in 1 and 2 are 2.2788(14) and 2.2756(5) A, respectively, which are typical values for Ru2(O2CR)4Cl and [Ru2(O2CR)4]+ compounds. The Ru-N distances are 2.257(8) A in 1 and 2.259(4) and 2.283(4) A in 2. The temperature dependence of the magnetic susceptibilities of compounds 1-3 reveals a weak antiferromagnetic interaction between Ru2 units (S = 3/2) through each polycyano anionic linker: g = 2.16, zJ = -0.33 cm(-1), D = 63.3 cm(-1) for 1; g = 2.15, zJ = -0.22 cm(-1), D = 58.0 cm(-1) for 2; and g = 2.10, zJ = -0.90 cm(-1), D = 75.0 cm(-1) for 3.     

Syntheses and Crystal Structures of Cobalt(II) and Nickel(II) Coordination Polymers with 3-Aminobenzoic Acid Ligand

1 INTRODUCTION Much research interest has been focused on metal- organic coordination polymers in past years because of the structural and topological novelty of these compounds and their potential applications as func- tional materials, such as catalyst, ion-exchange, gas sorption, optical material and molecule-based ma- gnet[1~6]. In this field, many organic bridging ligands such as bipyridine, polyaromatic carboxylate and re- lated species have been used to produce various types of met…