Electron-impact coherence parameters for the excitation of the 51 P state of Sr

Electron-photon polarization correlation measurements have been carried out for the excitation of the 5¹P state of Sr at electron impact energies of 30.3 and 58.4 eV and electron scattering angles of 20°–130° for 30.3 eV and 20°–100° for 58.4 eV. The resulting Stokes parametersP ₁,P ₂,P ₃ are used to derive the usual complete scattering parameter sets λ, χ and γ,L _⊥,P _l. New FOMBT calculations for these parameters are reported alongside the measured data and show substantial agreement with the experiment and with recent calculations by Srivastava et al.     

Rhodium- and iridium-manganese carbonyl complexes containing bridging Ph2PCH2PPh2 ligands

Treatment of mer,cis-[MnCl(CO)₂(dppm-PP′)(dppm-P)] with [Rh₂Cl₂(CO)₄] in the presence of CO and PF₆⁻ gives [Cl(OC)₂Mn(μ-dppm)₂Rh(CO)₂]PF₆ which might have a bridging chloride ligand. Similar treatment of mer,cis-[MnBr(CO)₂(dppm-PP')(dppm-P)] gave [Br(OC)₂Mn(μ-dppm)₂Rh(CO)₂]PF₆ which ³¹P-{¹H} NMR spectroscopy showed to be a mixture of two closely related species. Treatment of mer,cis-[MnCl(CO)₂(dppm-PP') (dppm-P)] with [Rh₂Cl₂(CO)₄] at −30°C probably gave [Cl(OC)₂Mn(μ-dppm)₂ Rh(CO)₂]Cl but this decomposes above 0°C: the corresponding dibromide was made similarly and is somewhat more stable than the dichloride. Treatment of mer,cis-[MnX(CO)₂(dppm-PP')(dppm-P)] (X = Cl or Br) with [IrCl(CO)₂(p-toluidine)] and CO-PF₆⁻ gave [X(OC)₂Mn(μ-dppm)₂Ir(CO)₂]PF₆. Neutral complexes of type [X(OC)₂Mn (μ-dppm)₂Ir(CO)X'] (X and X' = Cl or Br) are very labile and rapidly decompose to give [Ir(CO)(dppm-PP')₂]⁺ and other (unidentified) products. Treatment of mer,cis-[MnX-(CO)₂(dppm-PP')(dppm-P)] with [RhH(CO)(PPh₃)₃] gave [X(OC)Mn(μ-dppm)₂(μ-H)(μ-CO)Rh(CO)] (X = Cl or Br). These heterobimetallic compounds generally showed broad ¹³P-{¹H} resonances for the P nuclei bonded to Mn at ca 20°C due to some coupling with the ⁵⁵Mn nucleus (I = 100% abundant), but at −30°C these resonances sharpened up due to more rapid quadrupolar relaxation at the lower temperature. NMR and IR data are given.     

Zinc(II) complexes with the tetradentate schiff base ligand N,N′-bis(1-pyridin-2-yl-ethylidene)propane-1,3-diamine: Synthesis and crystal structures

Two new zinc(II) complexes [ZnL(N₃)]·BF₄ (1) and [ZnBrL]·BF₄ (2), derived from the tetradentate Schiff base ligand N,N′-bis(1-pyridin-2-yl-ethylidene)propane-1,3-diamine (L), are prepared and characterized by physicochemical methods and single crystal X-ray crystallography. The crystal of (1) is triclinic: space group P-1, a = 8.593(1) Å, b = 8.752(1) Å, c = 13.393(2) Å, α = 97.153(1)°, β = 93.046(1)°, γ = 91.577(1)°, V = 997.4(2) ų, Z = 2. The crystal of (2) is triclinic: space group P-1, a = 8.351(1) Å, b = 8.956(1) Å, c = 13.139(2) Å, α = 92.716(1)°, β = 94.241(2)°, γ = 95.016(1)°, V = 974.8(2) ų, Z = 2. The geometries of the penta-coordinated zinc atoms in both complexes are intermediate between the square pyramid and the trigonal bipyramid having the Addison parameters of 0.39 and 0.47 respectively. The syntheses of the complexes show distinct preference for the anions in the order Br^? > N ₃ ^? > CH₃COO^?.     

Crystal structures of new isostructural oxovanadium(V) complexes with hydrazone ligands

Two new isostructural methoxide-bridged dimeric oxovanadium(V) complexes [VO(L¹)(OMe)]₂ (1) and [VO(L²)(OMe)]₂ (2), where L¹ and L² are the deprotonated forms of 3-bromo-N′-[1-(2-hydroxyphenyl)×ethylidene]benzohydrazide (H₂L¹) and 3-chloro-N′-[1-(2-hydroxyphenyl)ethylidene]benzohydrazide (H₂L²) respectively, are synthesized and characterized by elemental analyses, IR spectra, and single crystal X-ray determination. Both crystals crystallize in the triclinic space group P-1. For 1, a = 7.5237(15) Å, b = 10.846(3) Å, c = 11.195(3) Å, α = 84.143(3)°, β = 72.244(3)°, γ = 77.869(3)°, V = 849.9(4) ų, Z = 1, R ₁ = 0.0634, wR ₂ = 0.1373. For 2, a = 7.493(2) Å, b = 10.740(3) Å, c = 11.109(3) Å, α = 84.569(2)°, β = 71.783(2)°, γ = 79.822(2)°, V = 835.0(4) ų, Z = 1, R ₁ = 0.0511, wR ₂ = 0.1076. Each V atom in the complexes is octahedrally coordinated.     

Layered coordination polymer of silver methanesulfonate with 2,3,5,6-tetramethylpyrazine

The complex [Ag₂(Me₄-Pyz)(CH₃SO₃)₂]·2H₂O is synthesized, and its structure is determined. The crystals are monoclinic, space group P2₁ /n,a = 11.821(1), b = 4.906(1), c = 15.782(1) Å,β = 94.34(1) °, V = 912.5(2) ų, ρ(calcd) = 2.104 g/cm³, Z = 2. The Ag⁺ ion is coordinated at the vertices of the distorted tetrahedron by the nitrogen atom of tetramethylpyrazine and three oxygen atoms of two methanesulfonate ions (Ag(1)-N(1) 2.283(2), Ag (1)-O(RSO ₃ ^? )2.386(3)-2.451(2) Å, angles at the Ag atom 86.8(1)°–129.1(1)°). The structure contains layers of sulfonate-silver chains and tetramethylpyrazine molecules extended along the direction [101].     

The synthesis of and nuclear magnetic resonance strudies on bimetallic chromium(0), or molybdenum(0) carbonyl complexes containing bridging trans-Ph2PCHCHPPh2 ligands: Crystal structure of [Mo2(CO)8(μ-trans-PH2PCHCHPPh2)2]

The trans-PH₂PCH=CHPPh₂ (t-dppe)-bridged bimetallic 10-membered ring complexes [M₂(CO)₈(μ-t0dppe)₂] (M = Cr or MO) have been synthesized by treatment of the metal hexacarbonyl with one equivalent of t-dppe at elevated temperature. the fluxional process in the Mo(μ-t-dppe) Mo ring has been studied by variable temperature ¹³P-{¹H} NMR spectroscopy and is characterised by a change from an A₄ spin system at +20°C to an AA′BB′ system at −100°C. The bimetallic complex [Mo₂(CO)₆(μ-tdppe)₃] has been prepared and ¹³P-{¹H} NMR studies indicate that in solution all four phosphorus nuclei are equivalent, even at −115°C. Attempts to prepare related heterobimetallic complexes are also described. Crystals of [Mo₂(CO)₈(μ-trans-Ph₂PCH=CHPPh₂)₂] are monoclinic, space group P2₁/a, with a 2020.2(5), b 1423.1(5), c 2145.1(5) pm, β 113.95(2)°, and Z = 4; final R factor 0.0465 for 5668 observed reflections. The structure shows two [Mo(CO)₄] moieties linked by two trans-dppe bridges to give a 10-membered Mo₂P₄C₄ ring.     

Skew-trapezoidal bipyramidal diorganotin(IV) bischelates. Crystal structure of dimethylbis(2-pyridinethiolato-N-oxide)tin(IV)

Dimethylbis(2-pyridinethiolato-N-oxide)tin(IV), Me₂Sn(2-SPyO)₂, crystallizes in space group P2₁/c with a 9.877(3), b 11.980(4), c 13.577(3) Å, β 109.1(2)° and Z = 4. The structure was refined to R_F = 0.036 for 2263 Mo-K_α observed reflections. The coordination geometry at tin is a skew-trapezoidal bipyramid, with the oxygen [SnO 2.356(3), 2.410(4) Å] and sulfur [SnS 2.536(1), 2.566(1) Å] atoms of the chelating groups occupying the trapezoidal plane and the methyl groups [SnC 2.106(6), 2.128(7) Å] occupying the apical positions. The methyl-tin-methyl skeleton is bent [CSnC 138.9(2)°]. The SSnS angle is 77.8(1)°, but the OSnO angle is opened to 136.7(1)° to accommodate the intruding methyl groups. The carbontincarbon angles predicted from quadrupole splitting (^119mSn Mössbauer) and one-bond ¹¹⁹Sn¹³C coupling constant (solution ¹³C NMR) data agree closely with the experimental value.     

Synthesis and crystal structure of the hydrated magnesium diphosphate Mg2P2O7·3.5H2O and its high temperature variant Mg2P2O7·H2O

The synthesis and crystal structure of a novel hydrated magnesium diphosphate and its high temperature variant are described. Both structures were solved from powder X-ray diffraction data. The room temperature variant with composition Mg₂P₂O₇·3.5H₂O crystallises in the monoclinic space group P2₁/c (No. 14) with a=10.9317(1), b=8.05578(9), c=9.2774(1) Å, β=90.201(1)°, V=816.99(2) ų and Z=4. The structure consists of sheets stacked along [100] which are linked through MgO₂(H₂O)₄ pillars into a three-dimensional framework with cavities containing water molecules. Within the sheets there are infinite edge-sharing chains of Mg octahedra along [010] which are cross linked by P₂O₇⁴⁻ groups. A high temperature variant exists around 200°C. The crystal structure of this compound with composition Mg₂P₂O₇·H₂O was solved and refined in the monoclinic space group C2/c (No. 15) with a=18.6596(4), b=7.9769(1), c=8.9757(2) Å, β=107.378(1)°, V=1275.01(4) ų, Z=8. The transformation to Mg₂P₂O₇·H₂O involves removal of the water molecules in the cavities and the water molecules of the Mg octahedral pillars in Mg₂P₂O₇·3.5H₂O. The sheets in Mg₂P₂O₇·3.5H₂O however remain unchanged during the transformation as the water molecule coordinating Mg here is retained. These sheets are linked through tetrahedral MgO₄ pillars into a three-dimensional structure containing infinite 10-membered ring channels along [001]. Both compounds have been further characterised by ³¹P MAS NMR spectroscopy, thermogravimetric analysis and high temperature powder X-ray diffraction.     

An examination of the relationship between the x-ray diffraction-derived molecular structure of chloro (1,11-diamino-3,6,9-trithiaundecane)cobalt(III) cation and its inner sphere reduction by iron(II)

The crystal structure of racemic [Co(NSSSN)Cl](ClO₄)Cl was determined by X-ray diffraction methods. It crystallizes in the monoclinic system, space group P2₁/c, with cell constants of a = 9.795(3), b = 10.412(3) and c = 16.323(8) Å, and β = 93.87(4)°; V = 1661 ųd (meas.; flotation) = 1.85 gm-cm^?3, d (calc.; Z = 4 molecules/unit cell) = 1.88 gm-cm^?3. The molecules, a racemic mixture, have the absolute configurations λλδλ or δδλδ at each of the four five-membered rings and resemble, in general, the so called αα conformer already described by Snow¹ in his study of the Co(tetraen)Cl²⁺ cation. However, the torsional angles at C2, C3 and C8, C9 in the two terminal C-C-NH₂ fragments are quite different in the two systems. For Co(tetraen)Cl²⁺ they are 44.7° and ?20.2° respectively, whereas for Co(NSSSN)C²⁺ the values –52.3° and –44.6° obtain. Also, the ring Co-S1-C3-C2-N1 does not have the classical, low energy conformation found in Co(tetraen)Cl²⁺. The presence of the larger Co-S bonds causes the two terminal -NH₂ groups to be pushed toward each other, and to minimize steric hindrance between adjacent -NH₂ hydrogens and ligand twists C2 down and staggers the terminal hydrogens. We visualize the propagation of these distortion effects in solution as being transferred from one side to the other across the entire ligand chain with concomittant effects on the activation of the precursor complex in electron transfer reactions, resulting in ~10⁷ rate enhancement over the Co(tetraen)Cl² system. Kinetic data for the reduction of Co(NSSSN)X²⁺ and Co(NSNSN)X²⁺ (X = Cl^?, Br^?) by Fe(II) is also presented and discussed.     

Low Temperature Activation of Tellurium and Resource-Efficient Synthesis of AuTe2 and Ag2Te in Ionic Liquids

The low temperature syntheses of AuTe₂ and Ag₂Te starting from the elements were investigated in the ionic liquids (ILs) [BMIm]X and [P₆₆₆₁₄]Z ([BMIm]⁺=1-butyl-3-methylimidazolium; X = Cl, [HSO₄]⁻, [P₆₆₆₁₄]⁺ = trihexyltetradecylphosphonium; Z = Cl⁻, Br⁻, dicyanamide [DCA]⁻, bis(trifluoromethylsulfonyl)imide [NTf₂]⁻, decanoate [dec]⁻, acetate [OAc]⁻, bis(2,4,4-trimethylpentyl)phosphinate [BTMP]⁻). Powder X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy revealed that [P₆₆₆₁₄]Cl is the most promising candidate for the single phase synthesis of AuTe₂ at 200 °C. Ag₂Te was obtained using the same ILs by reducing the temperature in the flask to 60 °C. Even at room temperature, quantitative yield was achieved by using either 2 mol % of [P₆₆₆₁₄]Cl in dichloromethane or a planetary ball mill. Diffusion experiments, ³¹P and ¹²⁵Te-NMR, and mass spectroscopy revealed one of the reaction mechanisms at 60 °C. Catalytic amounts of alkylphosphanes in commercial [P₆₆₆₁₄]Cl activate tellurium and form soluble phosphane tellurides, which react on the metal surface to solid telluride and the initial phosphane. In addition, a convenient method for the purification of [P₆₆₆₁₄]Cl was developed.     

New hydrogen-bonded dimeric and polymeric gold(I) complexes of the heterodifunctional ligand Ph2PNHP(O)Ph2

The preparation of several new gold(I) complexes by chloride metathesis of [AuCl(HL)] [HL=Ph₂PNHP(O)Ph₂] with either HL or K[Ph₂P(E)NP(E)Ph₂] (E=S or Se) is described. All compounds were characterised by a combination of ³¹P{¹H}, ¹H and IR spectroscopy, microanalysis and X-ray crystallography. X-ray structural studies reveal that [Au(HL)₂]Cl [monoclinic, space group P2₁/c, a=9.0726(3) Å, b=21.0847(6) Å, c=12.0131(3) Å, β=105.1090(10)°, V=2219 ų, Z=2, final R=3.97] forms a one dimensional polymeric structure in which alternating [Au(HL)₂]⁺ and Cl⁻ ions are linked through intermolecular N–H⋯Cl hydrogen-bonding. In contrast the three-co-ordinate compound [Au{Ph₂P(Se)NP(Se)Ph₂-Se,Se′}(HL)] [monoclinic, space group P2₁/a, a=21.6752(5) Å, b=9.1200(10) Å, c=24.0742(7) Å, β=106.080(2)°, V=4573 ų, Z=4, final R=8.94] forms hydrogen-bonded dimer pairs analogous to that previously observed in non-complexed HL. The X-ray crystal structure of the gold(I) precursor [AuCl(HL)] has also been determined: monoclinic, space group P2₁/c, a=10.217(8) Å, b=23.256(5) Å, c=20.086(5) Å, β=101.15(4)°, V=4683 ų, Z=8, final R=5.2. The X-ray crystal structure reveals intermolecular N–H⋯OP hydrogen-bonding between adjacent [AuCl(HL)] molecules forming infinite chains.     

Molecular structure of 5-[(triphenyl-phosphoranylidene)hydrazono]-exo-3-azatricyclo[5.2.1.02.6]decane-4-one

The molecular structure of 5-[(triphenylphosphoranylidene)hydrazono]-exo-3-azatricyclo[5.2.1.0^2.6]decane-4-one is determined. The C₂₇H₂₆N₃OP compound crystallizes in the space group P?1: a = 9.2163(9) Å, b = 11.1102(11) Å, c = 11.9397(12) Å, α = 74.284(2)°, β = 78.532(2)°, γ = 72.004(2)°.     

Synthesis and structure of a binuclear ruthenium 4-chlorobenzamidato complex

The compound Ru₂Cl(4-Cl-C₆H₄CONH)₄ was prepared by reaction of Ru₂Cl(O₂CCH₃)₄ with 4-Cl-C₆H₄CONH₂ at 180°C. Crystals of the composition Ru₂Cl(4-Cl-C₆H₄CONH)₄CH₃OH were obtained by slow diffusion of CH₃OH containing Et₄NCl into a Me₂SO solution of the compound. The structure of the crystalline product, which loses solvent of crystallization on removal from the mother liquor, was solved by X-ray crystallography by mounting a single crystal in a capillary containing the mother liquor. The crystals belong to the space group P1? (triclinic crystal system) with a = 12.731(3) Å, b = 14.389(3) Å, c = 12.604(3) Å, α = 103.41(2)°, β = 106.43(2)°, γ = 64.90(2)°, V = 1988.6(8) ų and Z = 2. There are two half ruthenium dimers linked by a Cl atom and an uncoordinated solvent CH₃OH molecule per asymmetric unit. The ruthenium dimers lie on two centers of inversion at 0, 0, 0 and 1/2, 0, 0. The chloride ions bridge dinuclear cations in the crystal, forming infinite zigzag chains. The average Ru-Ru distance is 2.296[1] Å and each ruthenium atom has a RuClN₂O₂ coordination sphere where the average Ru′-Ru-Cl angle is virtually linear (175.68[6]°). The metal oxidation states in the complex are + 2 and + 3, giving an average value of + 2.5. The arrangement of four bridging 4-Cl-benzamidato ligands is of the 2 : 2 type. The average Ru-N, Ru-O, Ru-Cl distances and Ru(1)-Cl(1)-Ru(2) angle are 2.036[6] Å, 2.044[5] Å, 2.583[2] Å and 117.26(8)°, respectively. The IR spectrum of the compound shows two N-H stretches at 3380 and 3340 cm^?1. The electronic spectrum of the compound in Me₂SO exhibits bands at 558 nm (ε = 340 M^?1 cm^?1), 425 nm (1000) and 320 nm (22,700).     

Mononuclear,three-coordinate metal thiolates: Preparation and crystal structures of [NBun4][Hg(SPh)3] and [NPrn4] [Pb(SPh)3]

Dissolution of HgO or PbO in methanolic solutions of NaSPh yields homogeneous solutions from which highly crystalline [NBuⁿ₄][Hg(SPh)₃] (1) or [NPrⁿ⁴][PB(SPh)₃] (2) can be isolated on addition of appropriate quaternary ammonium salts. 1 crystallizes in monoclinic space group P2₁/a with a = 20.663(7), b = 16.812(6), c = 9.757(3) Å, β = 95.52(2)° and Z = 4. The anion consists of a rare example of trigonal planar coordinated Hg; there are no weaker, intermolecular Hg ... S axial interactions. 2 crystallizes in triclinic space group Pl? with a = 12.689(7), b = 11.255(6), c = 12.046(7) Å, α = 107.93(3), β = 109.64(3), γ = 86.01(3)°, and Z = 2. The anion consists of a trigonal pyramidal coordinated PbS₃ unit. The structures were solved using data collected at approx. ? 160°C and refined to conventional R values of 5.7 and 4.6%, respectively for 1 and 2.     

Synthesis and crystal structure of the salt of the protonated thiamine cation with the palladium(II) tetrachloride anion [HTA]2[PdCl4]Cl2 · 2H2O

The reaction of thiamine chloride hydrochloride with a solution of palladium chloride in hydrochloric acid gave a protonated thiamine salt [HTA]₂[PdCl₄]Cl₂ · 2H₂O (I) (TA is 4-methyl-3-[(2??-methyl-4??-amino-3??,4??-dihydropyrimidinyl-5??)methyl]-5-(2-hydroxyethyl)thiazolium cation, C₁₂H₁₆N₃O₂S). The crystal structure of I was determined by X-ray diffraction. The crystals are triclinic: a = 11.459(8) ?, b = 12.239(8) ?, c = 6.910(1) ?, ?? = 103.24(3)°, ?? = 76.95(3)°, ?? = 106.04(3)°, Z = 2, space group P $\bar 1$ . The structural units of I are doubly charged [HTA]²⁺ cations, [PdCl₄]^2? and Cl^? anions, and crystallization water molecules combined by hydrogen bonds and electrostatic interactions. The planar thiazolium and pyrimidine rings are in the F conformation, ??_t = 1.0°, ??_p = ?86.6°, and the dihedral angle between the planes is 85.5°. The torsion angles of the hydroxyethyl group are as follows: C(9)C(10)C(11)O(1), 175.6°; S(1)C(9)C(10)C(11), 33.2°; it is involved in the hydrogen bond with the free Cl^? anion. The sulfur atom forms a short (3.052 ?) intermolecular S-Cl contact with the chlorine atom of the [PdCl₄]^2? anion, which forms supramolecular chains.     

Structure of bis(hexamethylenetetramine) hexaaquanickel(II)hexafluorotitanate(IV) monohydrate — [Ni(OH2)6][TiF6](Ur)2·H2O

The X-ray diffraction study of a single crystal with the composition NiTiF₆(Ur)₂·7H₂O is performed, where Ur = C₆H₁₂N₄ is an urotropine (hexamethylenetetramine) molecule. The compound crystallizes in the triclinic P-1 space group: a = 8.7220(5) Å, b = 9.1004(5) Å, c = 17.533(1) Å, α = 75.074(1)°, β = 88.530(1)°, γ = 62.558(1)°, Z = 2, d _x = 1.756 g/cm³, μ = 1.228 mm^?1, R = 0.0351. The crystalline compound is ionic. The structural unit consists of [Ni(OH₂)₆]²⁺ and [TiF₆]^2? ions and Ur and H₂O molecules. The structural formula of the compound is [Ni(OH₂)₆][TiF₆](Ur)₂·H₂O. Hydrogen bonds in the compound are studied and analyzed.     

Structure of a new schiff base cobalt(III) complex with antibacterial activity

A new Schiff base cobalt(III) complex with the formula [CoL¹L²(N₃)]·NO₃ (L¹ is 2-[1-(2-phenylaminoethylimino)ethyl]phenolate, L² is N-phenylethane-1,2-diamine) is prepared and characterized by physicochemical methods and single crystal X-ray determination. The complex crystallizes in the triclinic system space group P-1, with a = 8.504(2) Å, b = 14.973(3) Å, c = 20.676(4) Å, α = 100.021(3)°, β = 90.005(3)°, γ = 103.084(2)°, V = 2523.0(9) ų, Z = 4, R ₁ = 0.0732, and wR ₂ = 0.1182. Single crystal X-ray diffraction analysis reveals that the complex contains two mononuclear [CoL¹L²(N₃)]⁺ cations and two nitrate anions. The Co atom is six-coordinated in an octahedral geometry. The ligands and the cobalt(III) complex are screened in vitro for their antibacterial activity against Bacillus subtillis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aereuguinosa.     

Copper(I) complexes with 2-butyne-1,4-diol: Synthesis and crystal structure of the anionic π-complex (ImH)[CuCl2(HOCH2C≡CCH2OH)] (ImH[CuCl2(HOCH2C≡CCH2OH)] (ImH+ is imidazolium cation)

The crystalline complex ImH[CuCl₂(HOCH₂C≡CCH₂OH)] has been synthesized by the direct interaction of 2-butyne-1,4-diol with CuCl in concentrated aqueous solution of (ImH)Cl (ImH⁺ is imidazolium cation) and studied by X-ray crystallography. The crystals are triclinic, space group P $\overline 1 $ , a = 7.08(2) Å, b = 7.49(1) Å, c = 10.962(8) Å, α = 101.76(8)°, β = 95.85(8)°, γ = 99.57(8)°, Z = 2. The structure consists of stacks of discrete anions [CuCl₂(HOCH₂C≡CCH₂OH)]^? arranged along the [100] axis and [ImH]⁺ cations occupying the free space. The environment of π-coordinated Cu(I) atoms is trigonal and consists of two chlorine atoms and the C≡C bond of 2-butyne-1,4-diol molecule. The alcohol groups do not participate in the coordination, but they form strong hydrogen bonds N-H···O (H···O, 1.76(6) Å) and O-H···Cl(H···Cl, 2.29(5) Å).     

Crystal structures of azido or thiocyanato-coordinated nickel(II) complexes with tridentate Schiff bases

A new azido-coordinated nickel(II) complex [NiL¹(N₃)] (1) and a new thiocyanato-coordinated nickel(II) complex [NiL²(NCS)] (2), where L¹ and L² are the monoanionic forms of Schiff bases 2-[(2-isopropylaminoethylimino)methyl]-6-methylphenol and 2-[(2-dimethlaminoethylimino)methyl]-6-methylphenol respectively, are prepared and structurally characterized by elemental analysis, IR spectra, and single crystal X-ray crystallography. Complex 1 crystallizes in the triclinic space group P-1 with unit cell dimensions a = 8.812(2) Å, b = 9.433(3) Å, c = 9.488(2) Å, α = 81.933(2)°, β = 69.925(2)°, γ = 84.591(2)°, V = 732.5(3) ų, Z = 2, R ₁ = 0.0291, and wR ₂ = 0.0734. Complex 2 crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 7.4497(4) Å, b = 6.1933(3) Å, c = 31.5126(18) Å, β = 92.484(2)°, V = 1452.57(13) ų, Z = 4, R ₁ = 0.0307, and wR ₂ = 0.0668. The Ni atom in each of the complexes is coordinated by three donor atoms of the Schiff base ligand and by one N atom of the azide or thiocyanate ligand, forming a square planar geometry. The azide and thiocyanate anions readily coordinate to the complexes as secondary ligands.