SYNTHESIS AND CRYSTAL STRUCTURE OF TETRAIMIDAZOLE(DIAQUA)-MANGANESE(II) TEREPHTHALATE

Abstract

The title complex, [Mn(C₃H₄N₂)₄(H₂O)₂]·(C₈H₄O₄), was prepared by reaction of terephthalato (diaqua)manganese (II) with imidazole in ethanol/water solution. The complex crystallizes in space group C2/c with cell parameters a = 22.494(5), b = 7.741(2), c = 16.287(3)Å, β = 120.94(3)°, Z = 4. The complex consists of complex Mn(II) cations and uncoordinated terephthalate anions; the latter link cations through an H-bonding network. Thermal analyses and IR spectra are discussed in terms of the formation of the complex.     

Synthesis,structure and characterization of copper(II) and zinc(II) complexes based on 3-carboxyl-1,2,4-triazole

Two complexes [CuL₂(H₂O)₂] (1) and [ZnL₂(H₂O)₂] (2) (L?=?3-carboxyl-1,2,4-triazole (L)) have been synthesized and characterized by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group P ₂(1)/n, a?=?8.632(8)?Å, b?=?9.153(8)?Å, c?=?6.991(7)?Å, β?=?94.279(12)°, Z?=?2, R ₁?=?0.0296, wR ₂?=?0.0918. Compound 2 also crystallizes in the monoclinic space group P ₂(1)/n, a?=?4.937(3)?Å, b?=?18.107(10)?Å, c?=?6.344(4)?Å, β?=?106.839(7)°, Z?=?2, R ₁?=?0.0230, wR ₂?=?0.0556. Extensive intermolecular hydrogen bonds assemble 1 and 2 into three-dimensional (3D) supramolecular architectures, with eight-member H-bonded synthons. Compounds 1 and 2 were also characterized by element analysis, FT–IR, luminescence and EPR studies.     

SYNTHESIS AND STRUCTURES OF DICHLOROTETRAKIS-(PHENYLTHIOUREA) CADMIUM(II) AND CATENA-BIS(THIOCYANATE) BIS(PHENYLTHIOUREA)CADMIUM(II)

Abstract

Two new cadmium(II) complexes with phenylthiourea (PTU), namely Cd(PTU)₄Cl₂ (1) and [Cd₂(NCS)₂(μ₂-SCN)₂(PTU)₂(μ₂-PTU)₂] _n (2), have been prepared and characterized structurally by X-ray diffaction. Complex 1 crystallizes in the monoclinic space group C2/c, with a = 27.057(13), b = 8.108(3), c = 16.751(8) Å, β = 114.46°, V = 3345(3) ų, Z = 4. Complex 2 crystallizes in the triclinic space group P-1, with a = 9.336(3), b = 14.686(5), c = 16.911(5) Å, α = 71.36(2), β = 84.31(2), γ = 72.470(10)°, V = 2095.0(12) ų Z = 4. The structural analysis shows that each metal atom in both the mononuclear complex 1 and polynuclear complex 2 is octahedrally coordinated by four sulfur atoms and two chloro ligands or two nitrogen atoms from the thiocyanate groups, respectively. The PTU ligand can serve as either a monodentate ligand or a μ₂-bridging ligand upon coordination to a metal atom.     

Synthese und Struktur der Kronenetherkomplexe von Kaliumhexachlorodipalladat(II) und -diplatinat(II)

Synthesis and Structure of Crown Ether Complexes of Potassium Hexachlorodipalladate(II) and -diplatinate(II) K₂[MCl₄] (M ? Pd, Pt) reacts with an excess of crown ether 18-crown-6 in water to give the crown ether complexes of potassium hexachlorodipalladate(II) and -diplatinate(II) [K(18-cr-6)]₂[M₂Cl₆] (M ? Pd, 1 ; M ? Pt, 3 ), respectively, and in methylene chloride to give those of potassium tetrachloropalladate(II) and -platinate(II) [K(18-cr-6)]₂[MCl₄] ( 1 ) (M ? Pd, 2 ; M ? Pt, 4 ), respectively. 1 - 4 are characterized by microanalysis, NMR (¹H, ¹³C), and vibrational spectroscopy. The X-ray structure analyses of the isotypic complexes 1 (P2₁/c; a = 10,9678(8), b = 8,2991(7), c = 22,469(2) Å, β = 98,523(5)°; Z = 2) and 3 (P2₁/c; a = 10,934(3), b = 8.376(3), c = 22,410(5) Å, β = 98,77(3)°; Z = 2) reveal [M₂Cl₆]^2? anions of nearly D_2h symmetry and [K(18-cr-6)]⁺ cations, in which the distance of K⁺ to the mean plane of the crown ether defined by its six oxygen atoms amounts to 0,830(4) Å in 1 and 0,821(2) Å in 3 , respectively. There are tight contacts between cations and anions (d(K-Cl): 3,341(2)/3,260(2) Å ( 1 ); 3,348(4)/3,259(4) Å ( 3 )).     

A linear trinuclear cobalt(II) complex with 4-(2-pyridine)-1,2,4-triazole: synthesis,structure and characterization

The linear trinuclear cobalt(II) complex [Co₃(pytrz)₆(H₂O)₆](NO₃)₆ (1) with pytrz = 4-(2-pyridine)-1,2,4-triazole has been prepared and characterized. It crystallizes in the rhombohedral R-3 space group with Z = 3, a = 13.955(2), b = 13.955(2), c = 28.942(9) Å, γ = 120°, V = 4881.2(18) ų. The structure of 1 comprises the cation [Co₃(pytrz)₆(H₂O)₆]⁶⁺, in which linear trinuclear Co(II) units are bridged by six L ligands and have six aqua molecules as terminal ligands. The six free nitrates link the terminal aqua ligands through N–H ··· O hydrogen bonds with C₃ symmetry. 1 was characterized by FT-IR, electronic spectra and magnetic measurements. The variable-temperature magnetic measurements reveal weak anti-ferromagnetic interactions in 1.     

The Syntheses and crystal structures of trans-dichlorobis (10-thiabenzo-15-crown-5)-palladium(Ⅱ)and trans-dichlorobis-(10-selenabenzo-15-crown-5)palladium(Ⅱ)

The preparation and X-ray crystal structures of the adducts of 10-thiabenzo-15-crown-5 and 10-selenabenzo-15-crown-5 with PdCl2 are reported. [PdCl2(C14H20O4S)2] (1): or-thorhombic, space group Pbca with cell dimensions of a=17.285(5), 6=8.354(3), c=21.689(4) A, K=3131.9 A3, Z=4;R=0.0330 for 2301 reflections with I > 3o(I), [PdCl2(C14H2oO4Se)2] (2): monoclinic, space group P21/n with cell dimensions of a=18.928(4), b=8.912(3), c=9.813(2) A, β=96.90(2)0, V=1643.4 A3, Z=2; R=0.0289 for 2617 reflections with I> 3σ(I), Both complexes are monomeric, square-planar palladiurn(Ⅱ) compounds with the Pd(Ⅱ) ion situating on a crystal-lographic inversion centre, and the crown ligands all adopt the axial coordination with the Pd-S bond of 2.3233(7) A and the Pd-Se bond of 2.4357(3) A. Their complexing characteristics are discussed in brief.     

Synthesis,Structure and Properties of a Zinc(II) Complex with the Lapacholate Anion and Ethanol as Ligands

The reaction of lapachol, 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphtoquinone, C₁₅H₁₄O₃, with zinc acetate, in ethanol, produces a chelate formula Zn(C₁₅H₁₃O₃)₂(C₂H₆O)₂, whose structure has been determined by single crystal X-ray diffraction. It pertains to the triclinic system, space group P I (No. 2), a = 8.2380(3) Å, b = 9.4900(2) Å, c = 11.0110(4) Å, α = 112.536(2)°, β = 91.204(2)°, γ = 92.664(2)°, Z = 1. Some spectroscopic and chemical properties of the complex are also reported.     

DIRECT SYNTHESIS OF LEAD(II) COMPLEXES WITH TRIETHANOLAMINE USING LEAD(II) OXIDE AS STARTING MATERIAL

Abstract

A number of lead(II) complexes containing triethanolamine (L) is reported. The compounds were identified and characterized by chemical analyses and IR investigations. The crystal structure of bis(triethanolamine)lead(II) acetate was determined by X-ray crystallographic analysis. The compound crystallizes in space group C2/c with a = 10.373(2), b = 16.079(2), c = 13.707(3) Å, β = 99.36(2)°, V = 2255.7 ų, Z = 4, d(calculated) = 1.84 g cm^?3. The structure was refined by least-squares methods to a final value of the R of 0.025 for 3185 reflections with I > 3σ(I). The complex consists of eight coordinated [PbL₂]²⁺ cations and two CH₃COO^? anions joined together by hydrogen bonds between the oxygen atoms of the carboxyl groups and the hydroxyl hydrogens of ligands. The lead atom lies on a two-fold rotation axis and the structure of the coordination polyhedron is a distorted trigonododecahedron.     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato)Cu（Ⅱ） and Zn(Ⅱ） Complexes

The structures of [Cu (S₂CN (CH₂)₄)₂] (1) and [Zn₂(S₂CN‐(CH₂)₄)₄] (2) have been determined by X‐ray crystallography analysis. They are all isomorphous and triclinic, space group of P1^?, with Z = 1. The lattice parameters of compound 1 is: a = 0.63483(2) nm, b = 0.74972(3) nm, c=0.78390(1) mn, α = 75.912(2)°, β = 78.634(2)° and γ = 86.845(2)°; compound 2: a = 0.78707(6) nm, b=0.79823(6) nm, c = 1.23246(9) nm, α = 74.813(2)°, β = 73.048(2)° and γ = 88.036(2)°. The copper atom is located on a crystallographic inversion center and zinc atom lies across centers of symmetry. The Cu(II) ion has a square‐planar geometry while Zn(II) has a distorted tetrahedral geometry. The thermal gravity (TG) data indicate that no structural transitions in the two compounds were abserved and the decomposition products can adsorb gas. Also they all have a high thermal stability.     

Synthesis and Structural Characterization of the Helical Coordination Polymers [Co(phen)(oba)(H2O)2] and [Cd3(phen)3(oba)2(Hoba)2(H2O)2] (phen = 1, 10‐phenanthroline; oba = 4, 4′‐oxybis(benzoate)

Two coordination polymers, [Co(phen)(oba)(H₂O)₂] ( 1 ) and [Cd₃(phen)₃(oba)₂(Hoba)₂(H₂O)₂] ( 2 ) (oba = 4, 4′‐oxybis(benzoate), phen = 1, 10‐phenanthroline) have been synthesized under hydrothermal conditions. Complex 1 crystallizes in monoclinic, P2₁/n, a = 7.543(6), b = 33.05(2), c = 9.902(5)Å, β = 103.69(2)°, V = 2398(3)ų, Z = 4; 2 in monoclinic, P2/n, a = 15.11(1), b = 10.069(8), c = 28.02(2)Å, β = 101.83(1)°, V = 4174(5)ų, Z = 2. X‐ray single‐crystal diffraction investigations shows that the complexes 1 and 2 consist of helical chains, which are further assembled into layers and networks via supramolecular interactions such as π—π stacking interactions and hydrogen bonds, respectively. The results indicate that the coordination environment is one of the most important factors for assembly of single‐stranded helical chains into double‐stranded helical chains via supramolecular interactions.     

SYNTHESES,CRYSTAL STRUCTURES AND ELECTRONIC SPECTRA OF MIXED-LIGAND ZINC(II) COMPLEXES WITH DIIMINES AND DITHIOLATES

Abstract

Three zinc(II) complexes, [Zn(bipy)(dmit)]₂ (1), [Zn(phen)(dmit)]₂ (2) and Zn(py)(mnt) (3), where bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline, py = pyridine, H₂dmit = 4,5-dimer-capto-1,3-dithiol-2-thione, mnt = maleonitriledithiolate, have been synthesized and their crystal structures determined. Complex 1 is monoclinic, space group P2₁/c, with a = 11.570(3), b = 9.137(3), c = 15.051(6)Å, β = 109.56(2)°, Z = 2 and was refined to R ₁ = 0.039. Complex 2 is monoclinic, space group P2₁/n, with a = 9.363(2), b = 13.732(3), c = 12.767(3), β = 94.06(3)°, Z = 2 and was refined to R ₁ = 0.038. Complex 3 is orthorhombic, space group P2₁2₁2₁, with a = 8.621(3), b = 10.546(4), c = 16.848(2), Z = 4 and was refined to R ₁ = 0.040. IR and electronic absorption spectra were investigated.     

CRYSTAL STRUCTURES OF Cd(H2O)2Cu(CN)3·2H2O,K[Cd(H2O)2Cu2(CN)5]·2H2O AND K2[Cd(H2O)Cu4(CN)8]·1.5H2O. STRUCTURES OF MULTI-DIMENSIONAL FRAMEWORKS FORMED WITH CADMIUM(II), COPPER(I) AND BRIDGING CYANO GROUPS

Abstract

In an attempt to form new multi-dimensional structures of cyano complexes including cadmium(II) and copper(I), four new complexes were obtained successively from an aqueous solution at intervals of from a few days to a few months. The complex 1 obtained first was unstable in the atmosphere. The crystal structures of the other complexes (2–4) obtained from second to fourth were determined by single crystal X-ray structure determinations. Their crystal data are as follows: 2 Cd(H₂O)₂ Cu(CN)₃·2H₂O, monoclinic, C2/m, a = 14.038(1), b = 9.944(1), c = 7.738(1) Å, β = 116.019(7)°, Z = 4; 3 K[Cd(H₂O)₂Cu₂(CN)₅]·2H₂O, triclinic, PI, a = 17.429(9), b = 16.519(7), c = 10.085(5) Å, α = 128.60(3), β = 137.44(2), γ = 45.82(2)°, Z = 4; 4 K₂[Cd(H₂O)Cu₄(CN)₈]·1.5H₂O, monoclinic, C2/c, a = 19.387(2), b = 16.056(3), c = 12.663(2)Å, β = 110.419(9)°, Z = 4. The main structural feature found in the complexes is that the whole framework consists of two networks, a Cd-Cu(I)-CN complex network that has an infinite network formed with bridging cyano groups between the metal atoms and a network formed with hydrogen bonding among water molecules. The second network is connected to Cd in the Cd-Cu(I)-CN complex network via a water ligand coordinated to Cd. In 2 a planar network of [CdCu(CN)₃] complexes are stacked along the c axis and the second network links the stacked complexes. 3 has a stacked structure of [Cd(H₂O)₂Cu(CN)₅]^2? in a bi-layered structure. The second network of 3, which includes K⁺ ions with an electrostatic interaction, spreads over the crystal, penetrating vacant spaces of the metal complex network. 4 has a double lattice structure with a pair of enantiomeric three-dimensional [Cd(H₂O)Cu₄(CN)₈]^2? complexes inter-penetrating each other. There are three structural factors for forming these framwork structures: (1) a non-planar coordination structure for Cd(II) that extends the planar structure of the Cu(I)-CN complex to a three-dimensional structure for the Cd-Cu(I)-CN complex; (2) a trigonal planar coordination structure for Cu(I) that generates vacant space in the metal complex network and makes possible hydrogen bonds to form the second network; (3) structural distortions of bridging cyano groups and a coordination structure of Cu(I) that cause variations of the metal complex network structure.     

Palladium(II) Chloride Interaction with Chelating BIS(Phosphine Sulfides). Effect of the Ligand Structure on the Complex Geometry

Abstract

Interaction of PdCl₂ in chloroform with bis(phosphine sulfides) Ph₂P(S)?X?P(S)Ph₂ (X?CH₂, C(CH₃)₂, CH₂CH₂, NH, S, and SCH₂S) has been studied. Mechanism of the reaction has been found to vary dramatically with the identity of X. The structures of the resultant complexes were evaluated by UV and IR spectroscopy. Crystal structures were were determined by X-ray diffraction for two of the compounds (A: [Ph₂P(S)?(CH₂)₂?P(S)Ph₂]PdCl₂ · CH₃CN, P2₁/n, Z = 4, a = 10.104(2), b = 20.939(4), c = 14.034(3) Å, γ = 102.54(2)· B: [Ph₂P(S)?N?P(S)Ph₂]₂Pd · 2CHCl₃, Pl, Z = 1, a = 9.539(1), b = 12.333(3), c = 12.866 Å, α = 111.83(2)°, β = 96.70(3)° γ = 99.84(3)°).     

Crystal Structures of (18-Crown-6)-(2-Hydroxyethylammonium) Tetracyanonickelate(Ii) and 10-Amino-Decylammonium Tetracyanonickeltate(II)

Abstract

The crystal structures of the two title tetracyanonickelate(II) salts of organic ammonium ions, (18-crown-6)-(2-hydroxyethylammonium) tetracyanonickelate(II), I, and 10-aminodecylammonium tetracyano nick-elate(II), II, have been analyzed. I crystallizes in the monoclinic space group P2₁/n with a = 10.458(2), b = 8.267(3), c = 24.045(2) Å, β = 94.09(1)°, V = 2074(1) ų, Z = 2, R = 0.061 for 2274 reflections; II is triclinic P ₁ with a = 9.437(3), b = 10.094(3), c = 9.205(3)Å,a = 110.16(2), β = 112.72(3), γ = 69.16(2)°, V = 733.7(5) ų 2=1, R = 0.040 including all the hydrogen atoms refined for 2724 reflections. The square planar tetracyanonickelate(II) anion is in a favourable position to form hydrogen bonds via N with the hydroxyl group in I and the ammonio group in II, respectively.     

Transition Metal Halide Salts and Complexes of 2-Aminopyrimidine: Cobalt(II) and Nickel(II) compounds,Crystal Structures of Bis(2-Aminopyrimidinium)MX4 [M = Co,Ni; X = Cl,Br] and 2-Aminopyrimidinium(+2) [NiBr2(H2O)4]Br2

The reaction of MX₂ (M = Co(II), Ni(II); X = Cl, Br) with 2-aminopyrimidine in aqueous acid yields compounds [(2-apmH)₂MX₄], (2-apmH)₂[MX₄], or (2-apmH₂) [MX₂(H₂O)₄]X₂ (2-apmH = 2-aminopyrimidinium; 2-apmH₂ = 2-aminopyrimidinium(2+)). All compounds have been characterized by single crystal X-ray diffraction. The compounds [(2-apmH)₂MX₄] with M = Co, X = Cl (1); M = Ni, X = Cl (3); and M = Ni, X = Br (4) are isomorphous and crystallize as nearly square planar MX₄ units with the 2-apmH cations coordinated in the axial sites through the unprotonated ring nitrogen. (2-ApmH)₂[CoBr₄] (2) crystallizes as the salt with a nearly tetrahedral CuBr₄ ^2- anion. (2-ApmH₂)[NiBr₂(H₂O)₄]Br₂ (5) forms as a cocrystal of the neutral, six-coordinate nickel complex and (2-ampH₂)Br₂, stabilized by extensive hydrogen bonding. Crystal data (1): monoclinic, P2₁/c, a = 7.540(4), b = 12.954(4), c = 7.277(3) Å, β = 110.09(6), V = 667.4(5) ų, Z = 2, D_calc = 1.955 Mg/m³, μ = 2.079 mm^-1, R = 0.0501 for [|I|≥2(I)]. For (2): triclinic, P-1, a = 7.720(2), b = 7.916(2), c = 14.797(3) Å, α = 97.264(3), β = 104.788(3), γ = 105.171(3)°, V = 825.3(3) ų, Z = 2, D_calc = 2.296 Mg/m³, μ = 10.715 mm^-1, R = 0.0308 for [|I|≥2(I)]. For (3): monoclinic, P2₁/c, a = 7.595(3), b = 12.891(4), c = 7.204(3) Å, β = 111.07(3)°, V = 658.2 ų, Z = 2, D_calc = 1.982 Mg/m³, μ = 2.279 mm^-1, R = 0.0552 for [|I|≥2(I)]. For (4): monoclinic, P2₁/c, a = 7.840(2), b = 13.358(4), c = 7.518(2) Å, β = 110.923(3)°, V = 938.6(3) ų, Z = 2, D_calc = 2.577 Mg/m³, μ = 12.18 mm^-1, R = 0.0280 for [|I|≥2(I)]. For (5): orthorhombic, Pnma, a = 16.776(6), b = 11.943(4), c = 7.079(3) Å, V = 1418.2(9) ų, Z = 4, D_calc = 2.564 Mg/m³, μ = 12.639 mm^-1, R = 0.0381 for [|I|≥2σ(I)].     

SYNTHESIS AND X-RAY CRYSTAL STRUCTURE OF BIS (2-AMINOMETHYLAZIRIDINE)NICKEL(II) PERCHLORATE

Abstract

The structure of the big (2-aminomethylaziridine = azida)nickel(II) complex was determined by X-ray diffraction methods. The compound, [Ni(azida)₂](C1O₄)2, crystallizes in the triclinic space group P1, Z=l, with a = 7.3545(4), b = 8.5235(5), c = 6.2156(4)Å, α= 101.871(6). β = 103.217(6), γ= 111.283(4)°, and V= 335.07(5) ų. The crystal shows discrete centrosymmetncal [Ni(azida)]²⁺ units in which azida acts as bidentate chelating ligand through N aziridine and N amino atoms. Thus, Ni has a four-coordinate square-planar geometry with four nitrogens of azida. The aziridine ring is almost perpendicular to the coordination plane. The dihedral angle between the aziridine plane and the coordination plane is 75.28°.     

Bridging chlorides and hydroxides: syntheses and crystal structures of binuclear and tetranuclear NiII complexes derived from a reduced Schiff-base ligand 2-(2-pyridylmethylamino)ethanesulfonic acid

Two complexes, [Ni(pmt)(Cl)] (1) and [Ni₄(pmt)₄(OH)₄]·8H₂O (2) [Hpmt = 2-(2-pyridylmethylamino)ethanesulfonic acid], were synthesized by different experimental methods in methanol-water mixed solution. Compound 1 crystallizes in triclinic, space group P?1 with unit cell parameters: a = 8.315(2) Å, b = 8.383(2) Å, c = 9.128(2) Å, α = 103.654(2)°, β = 98.125(2)°, γ = 113.154(2)°, V = 548.6(2) ų, Z = 2. A pair of chlorides is μ ₂-bridges linking two Ni^II atoms in forming binuclear complex 1. The coordination environment at Ni^II is distorted square-pyramidal geometry. Compound (2) belongs to monoclinic, space group C2/c, with a = 16.5168(15) Å, b = 18.3718(17) Å, c = 17.5473(16) Å, α = γ = 90°, β = 93.3820(10)°, V = 5315.3(8) ų, Z = 4. Four hydroxides are μ ₃-bridges joining four Ni^II atoms to generate a cubic framework as a tetranuclear complex. The configuration at each Ni^II is distorted octahedral. Both π–π stacking of pyridine rings and intermolecular hydrogen bonds stabilize the solid state structures for 1 and 2.     

Preparation,thermal decomposition,and crystal structure of Zn(II) 2-chlorobenzoate complex with nicotinamide

A new Zn(II) 2-chlorobenzoate complex, [Zn(2-ClC₆H₄COO)₂(nad)₂] (nad = nicotinamide), was synthesized and characterized by elemental analysis, infrared (IR) spectroscopy, mass spectrometry, thermal analysis, and X-ray structure determination. The mechanism of thermal decomposition of the complex was studied by TG/DTG, DTA, IR spectroscopy, and mass spectrometry. The thermal decomposition is characterized as a two-step process. Zinc oxide was found as the final product of the thermal decomposition performed up to 900°C. Mass spectrometry was used to determine the volatiles released during thermal decomposition. The IR spectrum indicates that carboxylate is coordinated to zinc in monodentate coordination. [Zn(2-ClC₆H₄COO)₂(nad)₂] crystallizes in the monoclinic system, space group Pn, a = 10.376(2) Å, b = 10.100(1) Å, c = 12.604(1) Å, β = 100.79(1)°. The zinc is tetrahedrally coordinated by two nitrogens of nicotinamide and two oxygens of 2-chlorobenzoate.     

DIRECT SYNTHESIS AND CRYSTAL STRUCTURE OF DIIODOETHYLENDIAMINELEAD(II) DIMETHYLSULFOXIDE

Abstract

A direct method of obtaining PbEnI₂.DMSO is reported. The crystal structure of the compound was determined by X-ray techniques. PbEnI₂.DMSO is triclinic, space group P 1, C₄H₁₄I₂N₂PbS, a=10.225(3), b=10.132(3), c=6.900(2) Å; α=90.83(2), β=88.30(2), γ=106.35(4)°; V=685.6(4) ų; z=2, calculated density 2.92 gcm^?3. Neutral PbEnI₂ complexes are associated with DMSO molecules via H-bonds. The lead(II) ion is covalently linked with a chelated En molecule (Pb-N 2.46–2.48 Å) and I^? anions (Pb-I 3.087–3.343 Å). Covalently bonded atoms form an umbrella-like coordination Pb(II) polyhedron. The side containing the lone electron pair of the lead(II) ion has coordination completed by two I^? anions of neighbouring molecules with the Pb-I 3.621–3.627 Å.     

Copper(II) Halide Complexes of 2-Aminopyrimidines: Crystal Structures of [(2-aminopyrimidine) n CuCl2] (n=1,2) and (2-amino-5-bromopyrimidine)2CuBr2

The reaction of CuX₂(X=Cl, Br) with 2-aminopyrimidine in aqueous solution, or 2-amino-5-bromopyrimidine in aqueous acid yields compounds of the forms [LCuCl₂] _n (1), [L₂CuCl₂] (2) and [L'₂CuBr₂] (3) [L=2-aminopyrimidine; L'=2-amino-5-bromo-pyrimidine]. The three compounds all form layered structures in which each copper ion is coordinated to two 2-aminopyrimidine molecules and two halide ions. Common structural threads involve bridging ligation [either by monomeric (1) or hydrogen bonded ligand dimers (2 and 3)], N-H···X and N-H···N hydrogen bonding and π-π stacking interactions as well as semi-coordinate Cu···X bond formation (1 and 2) or Br···Br interactions (3). Compounds 1 and 2 crystallize as two-dimensional coordination polymers with asymmetrically bihalide bridged (CuX₂) _n chains cross-linked into sheets by the 2-aminopyrimidine molecules (1) or by hydrogen bonded L₂ dimers (2). The halide bibridged chains expand their primary copper coordination spheres to give 4 + 2 coordination spheres in 1 and 2. In 3, the layer structure involves coordination of the hydrogen bonded L'₂ dimers and C-Br···Br- interactions. Crystal data: (1): monoclinic, P2₁/m, a=3.929(1), b=12.373(2), c=7.050(1)å, β=91.206(4)°, V=342.7(1)&Aringsup3;, Z=2, D _calc= 2.225Mg/m³, μ=3.878 mm^-1, R=0.0269 for [|I|≥3σ(I)]. For (2): triclinic, P-1, a=4.095(4), b=7.309(5), c=10.123(6) å, α=86.28(6), β=78.44(6), γ=74.55(8)°, V=286.1(4) ų, Z=1, D _calc=1.884 Mg/m³, μ=2.360 mm^-1, R=0.0506 for [|I|≥2σ(I)]. For (3): triclinic, P-1, a=6.074(4), b=7.673(3), c=8.887(3) å, α=108.43(3) β=100.86(5), γ=106.96(4)°, V=357.0(3) ų, Z=1, D _calc=2.657 Mg/m³, μ=12.714mm^-1, R=0.0409 for [|I|≥2σ(I)].