Solid-State Synthesis and Structural Characterization of Hydrated Zinc (II) Tartrate Complex

Abstract  

A new dinuclear hydrated zinc (II) tartrate complex has been successfully synthesized via a solid-state reaction at low temperature under the presence of polyethylene glycol 400 as a structure-directed agent and structurally characterized by single-crystal X-ray diffraction, and further identified by element analyses, FT-IR spectra and TG/DTA measurements. It formulates as [Zn₄(C₄H₄O₆)₄(H₂O)₈]·(H₂O)₁₂ and crystallizes in monoclinic system, and the space group is P2 (1)/c with cell parameters a = 13.681(3), b = 17.059(3), c = 18.483(4) ?, β = 96.62(3)°, and Z = 4. The structure of the title complex consists of two crystallographic independent dimeric units of [Zn₂(C₄H₄O₆)₂(H₂O)₄], 12 lattice water molecules. In each dimeric unit, two tartrate dianions bridges the two Zn (II) ions by using one hydroxy oxygen and one carboxy oxygen atoms as donor atoms, respectively. Each Zinc atom is six-coordinated by four oxygen atoms from two tartrate dianions and two oxygen atoms from the water molecules.     

Two-Dimensional Hydrogen-Bonded Polymer from Nickel(II) Tetraaza Macrocyclic Complex and Succinate Ligand

Abstract  

The reaction of [Ni(L)]Cl₂·2H₂O (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12] docosane) with succinic acid (C₄H₆O₄) yields a 2D hydrogen-bonded polymer with formula [Ni(L)(C₄H₅O₄)₂] (1). This polymer complex has been characterized by X-ray crystallography, spectroscopy and cyclic voltammetry. The complex has a center of symmetry. The crystal structure of 1 exhibits a distorted octahedral geometry about Ni atom with four nitrogen atoms of the macrocycle and two oxygen atoms of the succinate ligand at the trans position. Compound 1 crystallizes in the monoclinic system C2/c with a = 14.8203(11), b = 12.3070(8), c = 17.4164(12) ?, β = 107.356(6)°, V = 3032.1(4) ?³, Z = 4. Electronic spectrum of 1 reveals a high-spin octahedral environment. Cyclic voltammetry of 1 undergoes two waves of a one-electron transfer corresponding to Ni^II/Ni^III and Ni^II/Ni^I processes.     

Synthesis and Characterization of Nickel(II) Complex of 3,14-Dimethyl-2,6,13,17-Tetraazatricyclo[14,4,01.18,07.12]Docosane Containing Pyrazine-2-Carboxylate Ligand

Abstract  

The reaction of [Ni(L)]Cl₂·2H₂O (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane) with pyrazine-2-carboxylic acid (H-pyc) yields mononuclear nickel(II) complex, [Ni(L)(pyc)₂]·2H₂O (1). This complex has been characterized by X-ray crystallography, electronic absorption and cyclic voltammetry. The crystal structure of 1 exhibits a distorted octahedral geometry with four nitrogen atoms of the macrocycle and two pyrazine-2-carboxylate ligands. It crystallizes in the triclinic system P-1 with a = 9.6643(17), b = 10.116(3), c = 16.99(4) ?, V = 1633(3) ?³, Z = 2. Electronic spectrum of 1 also reveals a high-spin octahedral environment. Cyclic voltammetry of 1 undergoes two waves of a one-electron transfer corresponding to Ni^II/Ni^III and Ni^II/Ni^I processes.     

Self-Assembly of Two Isomorphous Thiocyanate Complexes of Co(II) and Ni(II) with 3-Hydroxypicolinamide

Abstract  

The synthesis, thermal and spectral characterization, and crystal structure of isomorphous thiocyanate cobalt(II) and nickel(II) complexes with 3-hydroxypicolinamide (3-OHpia), [M(C₆H₆N₂O₂)₂(NCS)₂]·2H₂O, are reported. The metal(II) ions are chelated by two cis-oriented 3-OHpia and two thiocyanate ligands in distorted octahedral geometry. The distortion within the coordination sphere is mainly imposed by formation of the chelate rings. The compounds crystallize in monoclinic space group P2/c with two symmetrically independent molecules and a = 14.4945(2) ?, b = 8.5906(1) ?, c = 16.3865(3) ?, β = 105.987(2)°, Z = 4 (1) and a = 14.4927(5) ?, b = 8.5912(3) ?, c = 16.2712(6) ?, β = 105.740(4)°, Z = 4 (2). Commonly observed supramolecular amide synthons are not robust enough to accommodate thiocyanate ions and H₂O molecules. But instead, neutral complexes are linked through hydrogen bonds leading to two different hydrogen bonding ribbon motifs involving amide moieties and H₂O molecules [C(8)R ₂²(12) along c axis] and amide moieties and thiocyanate ions [C(8)R ₂²(16) along b axis] for symmetrically related molecules labelled as 1 [Co1 (1) and Ni1 (2)] and 2 [Co2 (1) and Ni2 (2)], respectively.     

Synthesis,Characterziation and SOD Activity of Manganese(II) Complexes with Aza-Macrocyclic Ligand

Abstract  

Two manganese(II) complexes, [Mn₂(L)(H₂O)₄]Cl₂·6H₂O(1) and [Mn₂L(NCS)₂(H₂O)₂]·3H₂O(2) (L is 1,2,4-triazolato)-4,12,17,25-tetramethyl-1,2,5,8,11,14,15,18,21,24-decaza-4,11,17,24-cyclohexaeicosatetraene) have been prepared by template synthesis method. They are characterized by elemental analysis and IR. Single-crystal X-ray analysis reveals that complex (1) crystallizes in space group P 2₁/c with a = 8.710(3), b = 14.720(5), c = 14.301(5) ?, α = 90, β = 105.801(14), γ = 90°. The complex [Mn₂(L)(H₂O)₄]Cl₂·6H₂O consists of two manganese(II) macrocyclic complexes in which two Mn(II) centers are linked by two triazolate units of the macrocyclic framework. Each manganese(II) ion is coordinated by five nitrogen atoms from the macrocycle and two oxygen atoms of the coordinated water. The manganese(II) center is in an approximately pentagonal-bipyramidal environment. The SOD activities of both complexes have also been investigated.     

A Novel Keggin-Type Aluminotungstate Dimeric Compound: H3.5[Ni(2,2′-bipy)3]3{[AlW 10VI W 2V O40Ni(2,2′-bipy)2(H2O)]2Na0.5}

Abstract  A novel dimeric compound H_3.5[Ni(2,2′-bipy)₃]₃{[AlW₁₂O₄₀Ni(2,2′-bipy)₂(H₂O)]₂Na_0.5} prepared by the hydrothermal method consists of a {[AlW₁₂O₄₀Ni(2,2′-bipy)₂(H₂O)]₂Na_0.5}^9.5− heteropolyanion, and in the anion, two reduced Keggin heteropolyanions [AlW^VI ₁₀W₂^VO₄₀]⁷⁻ are bridged via Na coordination ion by means of an O–Na1–O linkage (O atoms from the surface bridging oxygen atoms of [AlW^VI ₁₀W₂^VO₄₀]⁷⁻) and two Ni coordination ions are linked to the Na1 square planar moiety by making use of Ni–Ow–Na1–Ow–Ni bridges. The crystal belongs to the monoclinic-space group C2/c, a = 46.592(9), b = 14.306(3), c = 25.967(5) ?, β = 90.14(3)°, V = 17308(6) ?³, Z = 4, D _c  = 3.116 Mg/m³. Index Abstract  A novel dimeric compound H_3.5[Ni(2,2′-bipy)₃]₃{[AlW₁₂O₄₀Ni(2,2′-bipy)₂(H₂O)]₂Na_0.5} prepared by the hydrothermal method consists of a {[AlW₁₂O₄₀Ni(2,2′-bipy)₂(H₂O)]₂Na_0.5}^9.5− heteropolyanion, and in the anion, two reduced Keggin heterpolyanions [AlW^VI ₁₀W^V ₂O₄₀]⁷⁻ are bridged via Na coordination ion by means of an O–Na1–O linkage (O atoms from the surface bridging oxygen atoms of [AlW^VI ₁₀W^V ₂O₄₀]⁷⁻) and two Ni coordination ions are linked to the Na1 square planar moiety by making use of Ni7–Ow7–Na17–Ow7–Ni bridges.      

Synthesis and Crystal Structures of Ternary Copper(II) Complex Containing Salicylaldehyde Schiff Base and 4,4′-Bipyridine

Abstract  A new ternary mixed-ligand complex [Cu₂(sal-glu)₂(bipy)(H₂O)₂] · (H₂O) (bipy = 4,4′-bipyridine and sal-glu = salicylaldehyde l-glutamic Schiff base) has been synthesized and characterized by X-ray diffraction. It crystallizes in the triclinic system, space group P-1 with a = 9.6199(13) ?, b = 9.9111(13) ?, c = 9.9167(13) ?. The amino acid Schiff base coordinates to the Cu(II) ion in a tridentate mode including phenol-hydroxyl oxygen, carboxyl oxygen and amide nitrogen atom, while the bipy coordinates in bidentate bridging mode linking two Cu(II) ions. The [Cu₂(sal-glu)₂(bipy)(H₂O)₂] units are linked into 1-D chain structure and the bipy molecules are interspersed into parallel sheets via intermolecular hydrogen bonds. The carboxyl oxygen atoms, phenolic oxygen atoms and water oxygen atoms are involved in the extensive intermolecular hydrogen bond network between the water molecules and phenol-hydroxyl oxygen atoms from salicylaldehyde derived ligand. Graphical Abstract  A new ternary mixed-ligand complex [Cu₂(sal-glu)₂(bipy)(H₂O)₂]·(H₂O) (bipy = 4, 4′-bipyridine and sal-glu = salicylaldehyde l-glutamic Schiff base) crystallizes in the triclinic system, space group P-1 with a = 9.6199(13) ?, b = 9.9111(13) ?, c = 9.9167(13) ?. The amino acid Schiff base coordinates to the Cu(II) ion in a tridentate mode including phenol-hydroxyl oxygen, carboxyl oxygen and amide nitrogen atom, while the bipy coordinates in bidentate bridging mode linking two Cu(II) ions. The [Cu₂(sal-glu)₂(bipy)(H₂O)₂] units are linked into 1-D chain structure and the bipy molecules are interspersed into parallel sheets via intermolecular hydrogen bonds. The carboxyl oxygen atoms, phenolic oxygen atoms and water oxygen atoms are involved in the extensive intermolecular hydrogen bond network between the water molecules and phenol-hydroxyl oxygen atoms from salicylaldehyde derived ligand.      

The Structure and Fluorescence Property of a 3D Supramolecular Network [Cd2(2-mBIM)2Cl2(C4H4O4)(H2O)2(H2O)]n

Abstract  

A cadmium(II) coordination polymer [Cd₂(2-mBIM)₂Cl₂(C₄H₄O₄)(H₂O)₂(H₂O)] _n (1) (wherein 2-mBIM = bis(2-methylimidazo-1-yl) methane, C₄H₄O₄ = succinate anion) has been synthesized and characterized by X-ray diffraction. Complex 1 crystallizes in the monoclinic space group C2/c with a = 23.5265(15) ?, b = 7.3558(5) ?, c = 17.4771(11) ?, β = 90.3560(10)°, V = 3024.5(3) ?³, Z = 4. Each Cd(II) atom is octahedrally coordinated and connected with two adjacent Cd(II) atoms by two individual 2-mBIM ligands in a trans-configuration to form one-dimensional (1D) helical structure. Such 1D helical chain structures were connected to each other via the succinate anion ligands and result in the formation of a two-dimensional (2D) framework. Meanwhile, an overall three-dimensional (3D) supramolecular network was formed via the weak hydrogen bond interactions between metal-coordination and free water molecules.     

Synthesis, Crystal Structure and Properties of the Binuclear Complex [Sm2(C10H9N2O4)2(C10H8N2O4)2(H2O)4]

Abstract  A novel binuclear Smarium (III) complex with N-(2-propionic acid)-salicyloyl hydrazone (C₁₀H₁₀N₂O₄, H₃L) was prepared and characterized. The crystal structure of [Sm₂(H₂L)₂(HL)₂(H₂O)₄] (1) was determined by X-ray single crystal diffractometry. 1 crystallizes in the monoclinic systerm, space group P2(1)/c, with a = 0.10229(2), c = 31.549(7), b = 0.70599(15) nm, and Z = 4. In the structure, Sm(III) is nine-coordinated by carboxyl O and acyl O atoms and imido N atoms of two ligands (H₂L and HL forms) and O atoms from two water molecules. H₂L and HL act as tridentate ligands which form two stable five-numbered chelating rings sharing one edge in the keto form for each ligand, and the carboxyl groups of two ligands were coordinated via bidentated bridging form. The coordination polyhedron around Sm (III) was described as a monocapped square antiprism. The inter- and intramolecular hydrogen bonds resulted in a three-dimensional network and provided extra stability for the structure. The complex was researched the interaction with calf thymus DNA by electronic absorption titration and emission titration. The results show that the complex is bound to calf thymus DNA mainly by intercalation .The complex also shows good fluorescence property. Index Abstract  The title compound, [Sm₂(H₂L)₂(HL)₂(H₂O)₄] was synthesized by the treatment of N-(2-propionic acid)-salicyloyl hydrazone (C₁₀H₁₀N₂O₄, H₃L) and Sm(NO₃) · 4H₂O and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that Sm (III) is nine-coordinated by carboxyl O and acyl O atoms and imido N atoms of two ligands (H₂L and HL forms) and O atoms from two water molecules. The carboxyl groups of two ligands were coordinated via bidentated bridging form. The coordination polyhedron around Sm (III) was described as a monocapped square antiprism. The inter- and intramolecular hydrogen bonds resulted in a three-dimensional network and provided extra stability for the structure.      

Synthesis and crystal structure of a binuclear maleatocopper(II) complex with phenanthroline

The title copper(II) complex [Cu₂(C₄H₂O₄)₂(phen)₂]⋅4H₂O (phen = 1,10-phenanthroline) was prepared and its crystal structure was determined by X-ray diffraction method. The crystal belongs to space group C2/c with cell of a = 18.136(5), b = 12.505(5), and c = 14.617(5) Å, β = 103.440(5)^∘ and Z = 4. The Cu(II) atom assumes a square pyramidal coordination geometry with a longer Cu–O3 coordination distance [2.308(3) Å] in the apical direction. The carboxyl O3 atoms from two maleate dianion bridges two Cu(II) atoms to form the binuclear complex with a shorter Cu⋅sCu separation of 3.349(1) Å. The separations of 3.39(1) and 3.41(1) Å between parallel phen rings indicate the existence of aromatic stacking.     

Crystal Structure of bis(18-Crown-6)-bis(formato-O) dicaesium dihydrate

Abstract  The crystal structure of the title compound, [2Cs⁺(C₁₂H₂₄O₆)₂(CHO₂ ⁻)₂(H₂O)₂], was determined by an X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P2₁ /n with cell parameters a = 10.4278(7) ?, b = 10.0183(5) ?, c = 18.2383(12) ?, β = 93.723(5)°, V = 1910.3(2) ?³ and Z = 2. The Cs cations are bonded to each of the six O atoms of a crown ether ring, two water molecules, and one O atom of a formato anion. As a result of that, a centrosymmetric dimeric dinuclear complex is formed. The two halves of the dimer are connected by a ring of formato anions and water molecules which are linked by O–H···O hydrogen bonds. Index Abstract  The title compound, bis(18-crown-6)-bis(formato-O), caesium dihydrate, features a centrosymmetric dimeric dinuclear complex where two Cs cations are coordinated by six O atoms of a crown ether ring. The two halves of this complex are held together by a ring of formato anions and water molecules which are linked by hydrogen bonds.      

Synthesis and Crystal Structure Determination of Dimeric Co(II) and Ni(II) with Pyridine 2,6-Dicarboxylic Acid

Abstract  

Two new dimeric complexes of Ni and Co with pyridine 2,6-dicarboxylic acid were synthesized, the structure of both these complexes were determined by single crystal X-ray crystallography and was characterized spectrally with the help of IR and UV spectrometers and the magnetic moments of both the reported complexes were recorded. Both of these complexes crystallize in the monoclinic space group P 2₁/c1. For the dimeric cobalt complex, formula C₁₄ H₂₁ Co₂ N₂ O₁₅; a = 8.3950(3) ?; α = 90°, b = 27.3702(8) ?; β = 98.211(2)°, c = 9.6235(3) ?; γ = 90° and Z = 3. For the dimeric Nickel complex, formula C₁₄ H₂₁ Ni₂ N₂ O₁₅, a = 8.330(10) A; α = 90°, b = 27.266(5) A; β = 98.61(10)^o, c = 9.653(10) A; γ = 90° and Z = 4. Both the dimeric complexes were observed to be hexa-coordinated with two different types of donor atoms (nitrogen and oxygen). Details of the synthesis, structures and spectroscopic properties have been discussed.     

Crystal Structure and Characterization of [Ni(RPOEt)<Subscript>2</Subscript>(C<Subscript>2</Subscript>H<Subscript>5</Subscript>OH)<Subscript>2</Subscript>](ClO<Subscript>4</Subscript>)<Subscript>2</Subscript> [RPOEt = bis{(diphenylphosphinyl)methyl}ethyl phosphinate]

Abstract  

The compound [Ni(RPOEt)₂(C₂H₅OH)₂](ClO₄)₂ (1) [RPOEt = bis{(diphenylphosphinyl)methyl}ethyl phosphinate] has been prepared in the form of single crystals and characterized by elemental and thermal analyses, IR spectroscopy and by a single crystal X-ray diffraction study. The complex crystallizes in the triclinic P[`1] P\bar{1} space group with a = 9.8773(5), b = 13.741(1), c = 14.287(1) ?, α = 64.313(9), β = 70.280(5), γ = 89.973(7)o, V = 1620.5(2) ?³, and Z = 1. The nickel(II) atom in 1, situated at the centre of symmetry, is coordinated by four oxygen atoms from two RPOEt ligands and two oxygen atoms from two ethanol molecules in a slightly distorted octahedral environment. The third phosphoryl-oxygen atom from the phosphinate ligand is hydrogen bonded to the oxygen atom of the ethanol molecule coordinated to nickel(II). The complex [Ni(RPOEt)₂(C₂H₅OH)₂]²⁺ cations are linked by the C–H···O hydrogen bonds into one-dimensional chains and by the composite π···π and C–H···π phenyl interactions into a final three-dimensional structure.     

Hydrothermal Synthesis,Crystal Structure,and Luminescence Property of Two Lanthanide Coordination Polymers with Diglycolic Acid

Abstract  Two new coordination polymers {[Tb₂(C₄H₄O₅)₃ · 4H₂O] · 2H₂O} _n (1) and {[La₂(C₄H₄O₅)₃ · 3H₂O] · 3H₂O} _n (2) (C₄H₄O₅ ²⁻ = diglycolato) were prepared by hydrothermal reaction and characterized by X-ray crystallography. The two complexes have different network structures through carboxylate oxygen atoms and ether oxygen atoms from diglycolato ligands linking lanthanide ions. The characteristic transition bands ⁵D₄ → ⁷F_J (J = 6 − 3) of Tb(III) ion are observed in complex 1. Graphical Abstract  Two new coordination polymers {[Tb₂(C₄H₄O₅)₃ · 4H₂O] · 2H₂O} _n (1) and {[La₂(C₄H₄O₅)₃ · 3H₂O] · 3H₂O} _n (2) (C₄H₄O₅ ²⁻ = diglycolato) have network structures through the carboxylate oxygen atoms and ether oxygen atoms from diglycolato ligands. The emission spectrum of complex 1 indicates the ⁵D₄ → ⁷F_J (J = 6 − 3) transitions of Tb(III) ion.      

A New Microporous Hydrogen-Bonding Framework Constructed from 1-(4-Hydroxyphenyl)-5-Thioacetatetetrazole

Abstract  

The new complex with flexible heterocyclic carboxylate ligand, [Ba(HL⁻)₂(H₂O)₃]·H₂O (H₂L = 1-(4-Hydroxyphenyl)-5-thioacetatetetrazole), were synthesized and structurally determined by X-ray diffraction analysis. The complex belongs to the monoclinic system, space group C2/c. The center Ba(II) is nine-coordinated by six carboxylate oxygen atoms from four HL-ligands and three water molecules in a distorted monocapped square trans-prism geometry. The ligand serves as a bridge to link two adjacent Ba(II) atoms into a chain structure which are further assembled into the final three-dimensional supramolecular architecture with microporous open channel via hydrogen bonds.     

Hydrogen-bonded Three-dimensional Supramolecular Network Constructed by Dinuclear Ni(II) Macrocyclic Complex and 1,2,4,5-Benzenetetracarboxylate

Abstract  

A new coordination polymer [Ni₂(L)(H₂btec)]_n, (1) was obtained from the reaction of NiSO₄·6H₂O, macrocyclic ligand 3,6,9,17,20,23-hexaaza-29,30-dihydroxy-13,27-di-tert-butyl-tricyclo[23,3,1,1^11,15]triaconta-1(28),11,13,15(30),25,26-hexaene (H₂L), and 1,2,4,5-benzenetetracarboxylic acid (H₄btec) in methanol. Its structure was determined by X-ray diffraction analysis. The crystal is monoclinic C2/c space group with cell parameters a = 20.4923(3) ?, b = 14.2389(3) ?, c = 14.5130(2) ?, β = 97.441(2)°, V = 4199.05(12) ?³, and Z = 8. The X-ray analysis shows that each Ni (II) cation is six-coordinated by an O₃N₃ donor set. The macrocyclic complex [Ni₂L] ²⁺ are bridged by H₂btec²⁻ anions to form 1D chains, which are further joined via N–H···O hydrogen bonds to yield a 3D supramolecular structure. Thermogravimetric analysis (TGA) for the complex is discussed.     

Crystal Structure of Two Nickel Complexes with m-Aminophenol-N,N,O-Triacetic Acid, the Effect of Temperature in the Synthesis

Abstract  

Two nickel coordination compounds with m-aminophenol-N,N,O-triacetic acid (H₃L), [Ni(L)·(H₂O)₃]₂·Ni(H₂O)₆·4.3H₂O (1), and [Ni(L)·H₂O]₂·Ni(H₂O)₆ (2), were obtained under similar reaction conditions but at different synthesis temperature. Single crystal X-ray diffraction analysis reveals that both coordination compounds exhibit discrete dimeric entity structures and contain hexaaquanickel cations acting as counter-ions. Unit cell data for (1): triclinic, space group P-1, a = 7.9977(16), b = 10.475(2), c = 12.952(3) ? and α = 107.36(3), β = 99.66(3), γ = 96.15(3)°; and for (2): monoclinic, space group P2₁/c, a = 13.524(3), b = 8.5703(17), c = 13.820(3) ? and β = 95.25(3)°. In (1), O–H⋯O hydrogen bonds link the complex anions into a dimeric unit. But in (2), the dimeric unit is generated from two Ni centers bridged by two ligands. Extensive hydrogen bond interactions exist in both coordination compounds, and connect the complex anions, hexaaquanickel cations and/or water molecules, resulting in three-dimensional supramolecular structures. The compounds also have been characterized by elemental analysis, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), FT-IR and UV–Vis spectra.     

Synthesis and Crystal Structure of a New Cobalt(II) Complex: Bis(pyridine)bis(4,4,4-trifluoro-1-(6-methoxynaphthalen-2-yl)butane-1,3-dione) Cobalt(II)

Abstract  

A new Co(II) complex 2 with ligand 4,4,4-trifluoro-1-(6-methoxynaphthalen-2-yl) butane-1,3-dione 1 and pyridine are prepared and crystallized from an acetone solution. The obtained red and transparent crystal conforms to the empirical formula of Co(C₁₅H₁₀O₃F₃)₂·(C₅H₅N)₂. It crystallizes in monoclinic, space group C2/c with a = 23.3152(14), b = 12.0225(7), c = 15.3950(10) ?, β = 124.1360(10)°, V = 3571.8(4) ?³, Z = 4, C₄₀H₃₀CoF₆N₂O₆, Mr = 807.59, F(000) = 1652, Dc = 1.502 g/cm³, μ = 0.564 mm⁻¹, the final R = 0.0466 and wR = 0.1043 for 3901 observed reflections with I > 2σ(I). X-ray structural analysis revealed that the Co(II) atom is coordinated by two oxygen atoms of 1,3-dione ligands 1 and two nitrogen atoms of pyridines, forming a distorted octahedron coordination geometry.     

Crystal Structures of Two Aromatic Zinc(II) Carboxylates: [Zn(4-Chlorosalicylato)2(H2O)4]·2theophylline·(H2O)2 and Unique [Zn(5-Chlorosalicylato)2(isonicotinamide)2(H2O)]

Abstract  

The crystal structures of two zinc(II) 4-chloro- and 5-chlorosalicylate complexes, [Zn(4-ClC₆H₃-2-(OH)COO)₂(H₂O)₄]·2tph·(H₂O)₂ (I) and [Zn(5-ClC₆H₃-2-(OH)COO)₂(ina)₂(H₂O)] (II), where tph is theophylline and ina is isonicotinamide, have been determined using X-ray diffraction methods. Crystals of both (I) and (II) are triclinic, space group P-1, with Z = 1 in a cell with a = 7.2220(3), b = 8.59700(10), c = 16.0210(5) ?, α = 75.990(2), β = 83.959(2), γ = 68.455(2)°, V = 897.54(5) ?³ (I) and with Z = 2 in a cell with a = 11.4148(11), b = 11.5327(10), c = 12.0685(13) ?, α = 63.458(6), β = 87.547(8), γ = 89.387(7)°, V = 1419.9(2) ?³ (II). The coordination environment of the zinc(II) atom of compound (I) consists of two unidentate carboxylate oxygen atoms and four oxygen atoms of aqua ligands, forming a distorted octahedral configuration. Two theophylline molecules and the remaining water molecules are bound only by hydrogen bonds. The Zn atom of compound (II) is pentacoordinated with two unidentate carboxylate oxygen atoms, two pyridine nitrogen atoms of isonicotinamide ligands, and the oxygen atom of the aqua ligand, forming a distorted configuration between square pyramid and trigonal bipyramid. In both complexes intramolecular O–H···O hydrogen-bonding interactions are present. In the crystal structures, molecules are linked by intermolecular O–H···O and N–H···O hydrogen bonds. The structures are analyzed and compared to the similar Zn(II) complexes, with the chromophores ZnO₆ and ZnO₃N₂.     

Synthesis and Crystal Structure of [Ni(L)(Phen)(H<Subscript>2</Subscript>O)]·3.75H<Subscript>2</Subscript>O

Abstract  

The title compound, [Ni(L)(Phen)(H₂O)]·3.75H₂O, where L = (E)-2-(5-formyl-2-oxidobenzylideneamino)ethanesulfonate, was synthesized in aqueous methanol in the presence of Ni(II), Phen and the potassium salt of 2-{[(E)-(2-hydroxy-5{[(2-sulfoethyl)imino]methyl}phenyl)methylidene]amino}-1-ethanesulfonic acid. The complex crystallized in the space group of P-1 with a = 13.751 (2) ?, b = 14.797 (2) ?, c = 15.543 (2) ?, α = 105.86 (1)°, β = 103.51 (1)°, γ = 114.38 (1)°, and Z = 2. In [Ni(L)(Phen)(H₂O)], the Ni(II) was six coordinated with two O and one N from L, two N from Phen and one O from coordinated water, forming an octahedral geometry. There are two molecules in the asymmetric unit and concomitant differences in the Ni-ligand bond lengths.