Synthesis,Crystal Structure,and Magnetic Properties of (2,2′‐dipyridylamine)(X−) Copper(II) Complexes (X−: Cyanate,Dicyanamide, Acetate,Thiocyanato)

The synthesis, structure, and magnetic properties of four 2,2′‐dipyridylamine ligand (abbreviated as Hdpa) containing copper(II) complexes. There is one binuclear compound, which is [Cu₂(μ_1,1‐NCO)₂(NCO)₂(Hdpa)₂] ( 1 ), and three mononuclear compounds, which are [Cu{N(CN)₂}₂(Hdpa)₂] ( 2 ), [Cu(CH₃CO₂)(Hdpa)₂·N(CN)₂] ( 3 ), and [Cu(NCS)(Acac)] ( 4 ). Compounds 1 and 4 crystallize in the monoclinic system, space group P2(1)/c and Z = 4, with a = 8.2465(6) Å, b = 9.3059(7) Å, c = 16.0817(12) Å, β = 91.090(1)°, and V = 1233.90(16) ų for 1 and a = 7.6766(6) Å, b = 21.888(3) Å, c = 10.4678(12) Å, β = 90.301(2)°, and V= 1758.8(4) ų for 4 . Compounds 2 and 3 crystallize in the triclinic system, space group P‐1 and Z = 1, with a = 8.1140(3) Å, b = 8.2470(3) Å, c = 9.3120(4) Å, β = 102.2370(10)°, and V = 592.63(4) ų for 2 and a = 7.4780(2) Å, b = 12.5700(3) Å, c = 13.0450(3) Å, β = 96.351(2)°, and V = 1211.17(5) ų for 3 . Complex ( 1 ), the magnetic data was fitted by the Bleaney‐Bowers equation (1). A very good fit was derived with J = 23.96, Θ = ?1.5 (g = 1.97). Complex ( 1 ) shows the ferromagnetism. Complexes ( 2 ), ( 3 ) and ( 4 ) of have the it is the typical paramagnetic behavior of unpaired electrons. Under a low temperature around 25 K, complexes ( 2 ) and ( 3 ) show weak ferromagnetic behavior. They are the cause of hydrogen bonds.     

Synthesis of two novel cobalt complexes and their crystal structures

Two new cobalt complexes were successfully synthesized from the reaction of binaphthyl Schiff base 2 with Co(OAc)₂ in the presence of sodium methoxide at 80 °C for 24 h and Co(acac)₃ in toluene under reflux. Their unique crystal structures are unambiguously disclosed by X‐ray analysis. Complex 3 is triclinic, space group P1 , unit cell dimensions a = 10.742(2) Å, b = 11.153(2) Å, c = 12.715 Å, α = 79.865(3) °, β = 76.053 °, γ = 72.532(4) °, volume 1401.3(5) ų, Z = 2. Complex 4 is triclinic, space group P1 , unit cell dimensions a = 10.801(2) Å, b = 12.554(3) Å, c = 15.219(3) Å, α = 105.672(4) °, β = 103.048 °, γ = 104.594(4) °, volume 1824.8(7) ų, Z = 2, calculated density 1.428 Mg m⁻³. Copyright © 2003 John Wiley & Sons, Ltd.     

Structures and Properties of Novel Mononuclear Iron(III) Complexes with Benzimidazole Containing Tripodal Tetradentate Ligands

The iron(III) complexes of the tripodal benzimidazole‐containing ligands tris(2‐benzimidazolylmethyl)amine (ntb), bis(2‐benzimidazolylmethyl)(2‐hydroxyethyl)‐amine (bbimae) and tris(5,6‐dimethyl‐2‐benzimidazolylmethyl)amine (me₂ntb) are structural and functional models for intradiol cleaving catechol dioxygenases. The complexes [Fe(ntb)Cl₂]Cl · 3 CH₃OH ( 1 ; P 1, a = 9.830(2) Å, b = 12.542(3) Å, c = 13.139(3) Å, α = 82.88(3)°, β = 73.45(3)°, γ = 85.53(3)°, V = 1539.2(6) ų; Z = 2) and [Fe(bbimae)Cl₂]Cl ( 2 ; P2₁/n, a = 7.461(2) Å, b = 18.994(5) Å, c = 14.515(4) Å, β = 98.22(2)°, V = 2035.8(9) ų, Z = 4) have been characterized by X‐ray crystallography and spectroscopic methods. In the octahedrally coordinated complexes two cis coordination sites – essential for catechol binding – are occupied by chloride ligands. The significant intradiol cleaving catechol dioxygenase activity of the model complexes was examined using 3,5‐di‐tert‐butylcatechol as a substrate.     

Chirale Dimethylgalliumaminoalkoxide

Chiral Dimethylgallium Amino Alkoxides Me₃Ga reacts with (S)-1-methyl-2-pyrrolidinyl-methanol, (+);(–)-2-piperidyl-methanol, and (S)-α,α,-diphenyl-2-pyrrolidinyl-methanol in molar ratio 1 : 1 with formation of the corresponding dimethylgallium aminoalkoxides 1 – 3 . As a consequence of the Ga–N-interaction new centres of chirality containing asymmetric surrounded N-atoms are formed. Compounds 1 – 3 were characterized by their ¹H, ¹³C nmr and mass spectra. The crystal structures of 1 – 3 were determined by single crystal structure analysis. 1 and 2 are dimeric in solid state, 3 is forming monomeric molecules. 1 and 3 crystallize in the monoclinic space group P2₁ with Z = 2, a = 7.245(4), b = 11.887(3), c = 11.807(6) Å, β = 93.48(3)° for 1 and Z = 4, a = 11.0871(7); b = 6.539(4), c = 12.6919(8) Å, β = 107.04(1)° for 3 . 2 and 2 a crystallize in the monoclinic space groups C2/m and C2/c with Z = 2, a = 15.891(3), b = 9.526(2), c = 7.345(1) Å, β = 111.89(3)° for 2 and Z = 4, a = 19.374(4), b = 8.430(2), c = 19.961(4) Å, β = 100.09(3)° for 2 a .     

The Phase Diagram of the System [Ph4P]Br/BiBr3. Synthesis,Crystal Structure,Thermal Behaviour,and Vibrational Spectra of [Ph4P]3[Bi2Br9] · CH3COCH3 and two Modifications of [Ph4P]4[Bi6Br22]

The phase diagram of the system [Ph₄P]Br/BiBr₃ was investigated with the aid of DSC, TG and temperature dependent X‐ray powder diffraction measurements. By varying the reaction conditions, stoichiometry and crystallisation conditions of the reaction between BiBr₃ and [Ph₄P]Br four polynuclear bromobismuthates are formed. We report here the crystal structure of the solvation product [Ph₄P]₃[Bi₂Br₉] · CH₃COCH₃, which crystallises with monoclinic symmetry in the S. G. P2₁/n No. 14, a = 12.341(1), b = 32.005(3), c = 19.929(3) Å, β = 99.75(2)°, V = 7758(7) ų, Z = 4 and the crystal structures of two modifications of the compound [Ph₄P]₄[Bi₆Br₂₂]. The α‐form, crystallises with triclinic symmetry in the S. G. P1 No. 2, a = 13.507(4) Å, b = 14.434(4) Å, c = 17.709(5) Å, α = 81.34(2)°, β = 72.42(2)°, γ = 72.53(2)°, V = 3132.7(1) ų, Z = 2. The high‐temperature β‐form, crystallises with triclinic symmetry in the S. G. P1 No. 2, a = 13.893(4) Å, b = 14.267(3) Å, c = 16.580(3), α = 100.13(2)°, β = 96.56(2)°, γ = 110.01(2)°, V = 2985.5(1) ų, Z = 2. Lattice parameters of [Ph₄P]₄[Bi₈Br₂₈] are also given. The thermal behaviour of the compounds and in addition the vibrational spectra of [Ph₄P]₃[Bi₂Br₉] · CH₃COCH₃ are presented and discussed.     

The Structure of Hydrotris(imidazolyl)boratothallium(I) – the First Structurally Authenticated Tris(imidazolyl)borate Metal Complex

The title compound crystallizes in the monoclinic space group P2₁/n with a = 8.706(1), b = 9.192(1), c = 15.261(2) Å, β = 94.740(3)°, V = 1217.0(3) ų, Z = 4, D_calc = 2.278 g cm^–3. The tris(imidazolyl)borate ligand bridges between three thallium atoms. The structure consists of one‐dimensional twisted ladder‐like strands.     

Crystal structures of ruthenium(III) cis- and trans-trifluoroacetylacetonate

Single crystal X-ray diffraction analysis is used to determine the structures of ruthenium(III) cis and trans trifluoroacetylacetonate at a temperature of 150 K. The crystallographic data for cis-C₁₅H₁₂F₉O₆Ru are: a = 8.6562(3) Å, b = 12.6941(3) Å, c= 17.8776(5) Å, β = 93.129(1)°, P2₁/n space group, V = 1961.51(10) ų, Z = 4, d _x =1.897 g/cm³, R = 0.0565. For trans C₁₅H₁₂F₉O₆Ru they are: a = 13.4060(3) Å, b = 14.5946(3) Å, c = 20.1316(4) Å, Pcab space group, V = 3938.85(14) ų, Z = 8, d _x = 1.890 g/cm³, R = 0.0840. Both structures are molecular and built of neutral molecules; the metal atom coordinates six atoms of oxygen of three ligands of β-diketone. The R—O distances in cis Ru(tfac)₃ lie between 1.99 Å and 2.03 Å; in trans Ru(tfac)₃, 1.99 Å and 2.02 Å. The molecules in the crystal are bonded only by van der Waals interactions; in the structures of the cis and trans forms, the six shortest Ru…Ru distances lie within the limits of 7.601-8.656 Å and 7.326–7.714 Å respectively.     

The Structure of cis‐[Chloro(dimethylsulfoxide)bis(1, 10‐phenanthroline)ruthenium(II)]‐tetraphenylborate, [RuCl(DMSO)(1, 10‐phen)2][BPh4]

The complex cis‐[RuCl(DMSO)(phen)₂]BPh₄, where DMSO is dimethylsulfoxide and phen is 1, 10‐phenanthroline, crystallizes in the monoclinic space group P2₁/c with a = 19.505(4), b = 10.045(2), c = 21.199(4) Å, β = 90.137(4)°, V = 4153(2) ų, Z = 4, D_calc = 1.430 g cm^—3. The ruthenium coordination geometry is that of a slightly distorted octahedron with a cis‐RuN₄ClS arrangement of the ligand donor atoms. The Ru—Cl distance is 2.421(1) Å and the Ru—S distance 2.250(2) Å. The four Ru—N distances are 2.057(6), 2.066(4), 2.073(4), and 2.086(4) Å with the Ru—N bond trans to Cl the second shortest and the Ru—N bond trans to S the longest one.     

Weak Interactions in Silver Complexes of 15-Crown-5

Abstract

The X-ray crystal structures of two closely related Ag(I) complexes of 15-crown-5 and benzo-15-crown-5 are reported. In the case of [Ag(15-crown-5)₂][SbF₆] 1, pointing one of its oxygen atoms away from the Ag⁺ cation enables one of the crown ligands to take part in an intermolecular C?H…O hydrogen bond. The analogous benzo-15-crown-5 species, [Ag(benzo-15-crown-5)₂][SbF₆] 2, is too rigid to attain the necessary conformation. Crystal data for 1: P2_1/c, a = 8.4481(3), b = 25.5813(9), c = 13.2773(4) Å, β = 101.354(2)°. Z = 4, unique data: 5187 R ₁ [F ² > 2σ(F ²)] 0.0259. Compound 2: P1, a = 8.6511 (15) Å, b =10.2322(18) Å, c = 19.291(3) Å, α = 103.704 (2)°, β = 101.274(2)°, γ = 95.952(2)°, Z = 2, unique data: 5803 R ₁ [F ²>2σ(F ²)] 0.0931.     

Synthesis and Structural Study of Copper(I) or Silver(I) Complexes of 2,11‐Dithia‐4,5,6,7,8,9‐Hexahydro[3.3]paracyclophanes

The complexes of 2,11‐dithia‐4,5,6,7,8,9‐hexahydro[3.3]paracyclophane (dthhpcp) with Cu(I), i.e. [Cu₂I₂(dthhpcp)₂]·2H₂O 1 , or with Ag(I), i.e. [Ag(dthhpcp)(NO₃)]thf 2 and [Ag(dthpcp)(CF₃COO)] 3 , were prepared for structural study by single‐crystal X‐ray diffraction analysis. For these three complexes, dthhpcp serves as a bridging group in the polymeric structure through bridging sulfur atoms via metal, while the bonding of anion with the second metal atom forms the multi‐diminished structures. Complex 1 is a novel two‐dimensional coordination polymer composed of Cu₆ motifs, in which Cu₂I₂ formed a square planar unit to link the dthhpcp molecule. The two oxygen atoms of the nitrate anion as a bridge for two Ag atoms in complex 2 provides a three‐dimensional channel framework of silver(I) with a tetrahydrofuran molecule as a guest inside the open cavities. In contrast, the analogous reaction with silver triflouroacetate gave a complex 3 , which is composed of infinite linear chains of‐Ag‐dthhpcp‐Ag‐dthhpcp‐ along the a axis. Unit cell data: complex 1 , orthorhombic system, space group P2(1)2(1)2(1), a = 19.2982(11) Å b = 16.5661(10) Å, c = 25.3006(15) Å, β = 90°, Z = 8; complex 2 , orthorhombic system, space group Pna2(1), a = 8.8595(6) Å, b = 12.6901(9) Å, c = 19.8449(14) Å, β = 90°, Z = 4; complex 3 , monoclinic system, space group P2(1)/n, a = 8.845(3) Å, b = 20.841(6) Å, c = 11.061(3) Å, β = 107.832(6)°, Z = 4.     

Intermetallic Phases in the Ca‐Cu‐Sn System

Twelve ternary alloys in the Ca‐Cu‐Sn system were synthesized as a test on the existing phases. They were prepared from the elements sealed under argon in Ta crucibles, melted in an induction furnace and annealed at 700 °C or 600 °C. Four ordered compounds were found: CaCuSn (YbAuSn type), Imm2, a = 4.597(1) Å, b = 22.027(2) Å, c = 7.939(1) Å, Z = 12, wR2 = 0.080, 1683 F² values; Ca₃Cu₈Sn₄ (Nd₃Co₈Sn₄ type), P6₃mc, a = 9.125(1) Å, c = 7.728(1) Å, Z = 2, wR2 = 0.087, 704 F² values; CaCu₂Sn₂ (new structure type), C2/m, a = 10.943(3) Å, b = 4.222(1) Å, c = 4.834(1) Å, β = 107.94(1)°, Z = 2, wR2 = 0.051, 343 F² values; CaCu₉Sn₄ (LaFe₉Si₄ type), I4/mcm, a = 8.630(1) Å, c = 12.402(1) Å, Z = 4, wR2 = 0.047, 566 F² values. In all phases the shortest Cu‐Sn distances are in the range 2.59‐2.66Å, while the shortest Cu‐Cu distances are practically the same, 2.53‐2.54Å, except CaCuSn where no Cu‐Cu contacts occur.     

CRYSTAL STRUCTURES AND TRIBOLUMINESCENT ACTIVITIES OF SAMARIUM(III) COMPLEXES

Abstract

The triboluminescence spectra and crystal structures of 1,2-dimethylpyridinium tetrakis(2-thenoyltrifluoroacetonato)samarium(III) (1) and 1,2,6-trimethylpyridinium tetrakis(2-thenoyltrifluoroacetonato)samarium(III) (2) were determined. The triboluminescent maximums are similar to those of the photoluminescence. Complex 1 is centrosymmetric and the triboluminescent emission may correlate with the disorder of all S atoms, all CF₃ groups and the cation. The triboluminescent activity of complex 2 may correlate with its noncentrosymmetric space group. Complex 1 crystallizes in the monoclinic space group P2₁/a with cell parameters a = 19.874(2) Å, b = 22.922(2)Å, c = 21.188(1)Å, β = 108.126(6)°, V = 9173(1)ų; Z = 8; R = 0.0758 and R_w = 0.1315. Complex 2 crystallizes in the monoclinic space group Pn with cell parameters a = 11.2808(6)Å, b = 11.0199(5)Å c c = 18.4336(9)Å, β = 108.126(6)° V = 2285.28(19)ų; Z = 4; R = 0.0347 and R_w = 0.0900. All the structures were refined by full-matrix least squares methods.     

Crystal Structures of Alkali Metal Peroxodiphosphates

Peroxodiphosphates of alkali metals can be prepared from K₄P₂O₈, which is synthesized by electrolysis, in metathesis reactions with the corresponding perchlorates. Single crystals have been obtained by diffusion of methanol into aqueous solutions of the peroxodiphosphates. The crystal structures of Li₄P₂O₈·4H₂O (P2₁/n; a = 8.057(2) Å, b = 5.074(1) Å, c = 12.288(3) Å, β = 100.53(2)°; V = 493.9(2) ų; Z = 2), Na₄P₂O₈·18H₂O (at 130 K: P6₁; a = 9.0984(14) Å, c = 49.926(13) Å; V = 3579.2(12) ų; Z = 6) and K₄P₂O₈ (P2₁/c; a = 5.9041(15) Å, b = 10.254(2) Å, c = 7.356(2) Å, β = 99.05(3)°; V = 439.79(18) ų; Z = 2) have been determined by X‐ray diffraction. In the Li salt the cations are tetrahedrally coordinated by one water molecule and three oxygen atoms of the anions, whereas the Na salt is characterized by binuclear [Na₂(H₂O)₉]²⁺ complexes. At low temperatures, the latter undergoes a phase transition from a structure with disordered anions to a completely ordered phase. K₄P₂O₈ is solvent‐free and exhibits irregular cation coordination. The structure of the peroxodiphosphate anion is very similar in all compounds; the mean O–O distance is 1.49(1) Å. In addition, the structure determination of K₄(HPO₄)₂·3H₂O₂ (P2₁/n; a = 6.076(1) Å, b = 6.579(1) Å, c = 17.215(2) Å, β = 99.73(1)°; V = 678.26(17) ų; Z = 2), which can be mistaken for K₄P₂O₈, is presented.     

Extraction and isolation of the One-electron Oxidized [(Zr6Be)Cl18]5− and [(Zr6Be)Cl18]4− Clusters from solid state precursors

One-electron oxidized zirconium chloride clusters were obtained from solid state precursors Rb₅Zr₆Cl₁₈B and K₃Zr₆Cl₁₅Be by dissolution in CH₃CN in the presence of Et₄NCl and isolated as the salts (Et₄N)₄Zr₆Cl₁₈B · 2 CH₃CN and (Et₄N)₅Zr₆Cl₁₈Be · 3 CH₃CN. (Et₄N)₄Zr₆Cl₁₈B · 2 CH₃CN crystallizes in the space group P1 (#2) with a = 12.329(5) Å, b = 12.657(6) Å, c = 13.136(8) Å, α = 118.28(4)°, β = 93.45(4)°, γ = 105.54(3)°, V = 1696(2) ų, and Z = 1. (Et₄N)₅Zr₆Cl₁₈Be · 3 CH₃CN was refined in the space group C2/c (# 15) with a = 24.166(11) Å, b = 13.265(6) Å, c = 25.86(2) Å, β = 104.21(4)°, V = 8037(7) ų, and Z = 4; the space group reflects the pseudo-symmetry of the crystal, the true symmetry of the structure is lower. The removal of one electron from the Zr? Zr bonding HOMO of both clusters results in cluster expansion of similar magnitude in both compounds. Moisture from the added Et₄NCl is the likely oxidant, but the possibility that acetonitrile may be reduced by [(Zr₆Be)Cl₁₈]^6? is not ruled out.     

Two New Modifications of [P(C6H5)4]2[Cu2I4]

Single crystals of two new modifications of [P(C₆H₅)₄]₂[Cu₂I₄] were obtained by reaction of granulated copper with iodine and [P(C₆H₅)₄]I in dry acetone under nitrogen atmosphere. They crystallise monoclinically, space group P2₁/n (No. 14), a = 11.550(6), b = 7.236(2), c = 27.232(13) Å, β = 98.13(3)°, V = 2253(2) ų, and Z = 2 ([P(C₆H₅)₄]₂[Cu₂I₄]-C), and space group Cc (No. 9), a = 17.133(5), b = 15.941(5), c = 18.762 (6) Å, β = 114.02(1)°, V = 4681(3) ų, and Z = 4 ([P(C₆H₅)₄]₂[Cu₂I₄]-D), respectively. In these compounds the [CuI₂]^? anions form dimers di-μ-iodo-diiodocuprate(I), which are either planar ( C ) or folded ( D ).     

Foreword

Abstract

The crystal structure of the dinucleating 2,2′:6′,2″-terpyridine ligand 6′,6″-bis(2-pyridyl)-2,2′:4′,4″:2″,2?-quaterpyridine (btpy) has been determined and the two metal-binding tpy domains shown to be essentially planar and co-planar (P 1, a = 6.304(2), b = 8.208(2), c = 11.535(3) Å, α = 97.42(2), β = 104.25(2), γ = 96.23(2)°, Z = 1, d _c = 1.36 g cm^?3, 2214 unique observed reflections with I > 1.5[sgrave] (I), R = 0.0583); a methodology involving sequential reaction with non-labile and labile metal centres allows the specific assembly of heterometallic supramolecular oligomers such as [(Xtpy)Ru(btpy)M(btpy)Ru(Ytpy)]ⁿ⁺ (M = cobalt(II), cobalt(III) or iron).     

Conformational Studies of Dibenzo-30-crown-10 Complexes. Syntheses and Crystal Structures of Potassium and Ammonium Hexafluorophosphate Complexes

Abstract

Crown ether complexes formed by the dibenzo–30-crown–10 (DB30C10) with potassium and ammonium hexafluorophosphate have been prepared and their crystal structures have been determined by single crystal X-ray analyses. The potassium complex (compound 1) consists of [K(DB30C10)]⁺ cation and PF₆ ^? anion. Crystals are monoclinic, space group P2/n, with a = 11.9106(3), b = 9.8382(5), c = 14.3062(3) Å, β = 97.581(3)°, V = 1661.7(1) ų, D_c = 1.440 g cm^?3, Z = 4, R = 0.0675 for 2528 unique observed reflections. The potassium atom is coordinated to the ten oxygen atoms of the crown ligand at the distance from 2.859(3) to 2.930(3) Å. The ammonium complex (compound 2) has also 1:1 crown—cation ratio. Crystals are monoclinic, space group P2₁/n, with a = 12.5061(6), b = 19.3724(5), c = 14.2203(9) Å, β = 102.476(5)°, V = 3363.8(3) ų, D_c = 1.501 g cm^?3, Z = 4, R = 0.0677 for 4172 unique observed reflections. The ammonium cation is completely enclosed with crown oxygen atoms forming seven hydrogen bonds. The conformation of previously reported dibenzo-30-crown-10 complexes with potassium salts were investigated using polar coordinate maps.     

Two crystalline polymorphic forms of α-(<Emphasis Type="Italic">N</Emphasis>-benzoxazolin-2-one)acetic acid

Two crystalline polymorphic forms of α-(N-benzoxazolin-2-one)acetic acid (BAA) are prepared by changing the temperature of its crystallization from solution in ethanol. Crystallographic data of the α-form are determined: a = 12.7769(17) Å, b = 8.2574(9) Å, c = 16.7390(19) Å, β = 105.087(13)°, space group C2/c, V = 1705.2(4) ų, and Z = 8, while those of β form are a = 5.2854(4) Å, b = 5.9880(4) Å, c = 13.4509(5) Å, β = 94.666(4)°, space group P2₁, V = 424.30(4) ų, and Z = 2. It is found that BAA molecules of the α form combine into infinite one-dimensional chains arranged along axis b by means of O?H···O and C?H···O hydrogen bonds, and these chains are crosslinked via C?H···O hydrogen bonds to form a threedimensional structure. The β form has another system of hydrogen bonds, one of which is bifurcated (O4···O2, O4···O3), and the π–π-interactions between the benzoxazolinone fragments of BAA molecules combined into a chain also arranged along axis b are observed. Calorimetric analysis shows that the polymorphic transition from the α form to the β form occurs at 129°C.     

Syntheses and crystal structures of two maleonitriledithiolate complexes containing the 1-(R-benzyl)pyrazinium cation (R = 4′-nitro or 4′-bromo)

The complexes [NO₂BzPz]₂[Ni(mnt)₂] (1) and [BrBzPz]₂[Pd(mnt)₂] (2) have been prepared by reaction of Na₂mnt, NiCl₂·6H₂O or PdCl₂, and the corresponding 1-(R-benzyl)pyrazinium bromide salt (R = 4′-nitro, R = 4′-bromo). Crystallographic data for 1: monoclinic, P2₁/n, a = 7.3494(15), b = 15.223(3), c = 15.054(3)?Å, β = 102.42(3)°, V = 1644.8(6)?ų, Z = 2. Data for 2: monoclinic, P2₁/n, a = 7.399(2), b = 19.024(4), c = 12.224(2)?Å, β = 94.62(3)°, V = 1715.0(7)?ų, Z = 4. In both complexes, the [M(mnt)₂]^2? anion has a centre of symmetry at the metal atom and two cations are related to each other by the symmetry centre. The [M(mnt)₂]^2? anion exhibits a quasi-planar structure in both complexes, which show similar crystal packing.     

Synthesis and crystal structures of the zinc(II) complexes with a tridentate Schiff base (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine

Two new isostructural zinc(II) complexes, [ZnCl₂(L)] (I) and [ZnBr₂(L)] (II), derived from the Schiff base ligand (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine (L), have been prepared and characterized by physicochemical methods and single-crystal X-ray crystallography. The crystal of I is monoclinic: space group P2₁/c, a = 11.699(3) Å, b = 8.460(2) Å, c = 14.766(3) Å, β = 99.686(3)°, V = 1440.6(6) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 8.166(2) Å, b = 15.153(3) Å, c = 11.966(2) Å, β = 96.964(2)°, V = 1469.7(5) ų, Z = 4. The geometry of the pentacoordinated zinc atoms in both complexes is best described as a square pyramid.