Hydrogen Bonded 3D Supramolecular Architectures of Two Organic Salts Assembled from 2-Aminoheterocyclic Compounds and Phosphoric Acid

Abstract  

Two phosphate salts (2-aminopyrimidine): (phosphoric acid): H₂O [HL1⁺ (H₂PO₄) ⁻ ]·H₂O (1), and (4-phenylthiazol-2-amine): (phosphoric acid) [HL2⁺·(H₂PO₄)⁻] (2) based on 2-aminoheterocyclic compounds, 2-aminopyrimidine (L1), and 4-phenylthiazol-2-amine (L2) were prepared and structurally characterized by X-ray crystallography. Compound 1 crystallizes in the triclinic, space group P-1, with a = 6.2201(7) Å, b = 8.6139(9) Å, c = 9.4800(10) Å, α = 109.685(2)°, β = 106.3340(10)°, γ = 95.4450(10)°, V = 448.72(8) Å³, Z = 2. For 1, the cations were linked to each other via intermolecular C–H···N hydrogen bonds to form a 1-D chain structure running along the a-axis direction. The anions and the water molecules were connected alternatively along the a-axis direction through O–H···O hydrogen bonds to form a 1-D chain also. The cationic chains and the anionic chains were alternatively connected along the c-axis direction through N–H···O and C–H···O hydrogen bonds to form a 2D corrugated sheet. Adjacent sheets were combined together through π–π interaction to form double sheet. These double sheets were further joined together by O–H···O and N–H···O hydrogen bonds to produce a 3D network structure. Compound 2 crystallizes in the Orthorhombic, space group Pbca, with a = 10.1929(10) Å, b = 8.4406(9) Å, c = 27.589(2) Å, α = 90°, β = 90°, γ = 90°, V = 2373.6(4) Å³, Z = 8. In 2, the phosphates formed 1D chain along the b-axis through two P–O–H···O = P hydrogen bonds. The cations formed 1D zigzag chain along the b-axis direction under the CH–π interaction. The anionic chains were intercalated between two adjacent cationic chains through N–H···O, O–H···O, C–H···O, and O–S contacts. Such stacking repeated along the c-axis direction to form a 3D network structure.     

Self-Assembled Hydrogen-Bonding Chains of Copper(II) 2-Nitrobenzoate with Nicotinamide

Abstract  

The synthesis, spectral characterization and crystal structure of two new nitrobenzoatocopper(II) complexes, namely, [Cu₂(2-O₂Nbz)₄(nia)₂]·ACN (1) and [Cu₂(2-O₂Nbz)₄(ACN)₂] (2) (where 2-O₂Nbz = 2-nitrobenzoate, nia = nicotinamide and ACN = acetonitrile) are reported. The complexes 1 and 2 form dinuclear units of the paddle-wheel type around the crystallographic inversion centers. The copper ions are bridged by four 2-nitrobenzoate anions and the neutral N-donor ligands, viz. nicotinamide in 1 and acetonitrile in 2, are coordinated at apical positions. Selected geometric parameters of both complexes are compared with values for related tetra-2-nitrobenzoate complexes of copper(II) as well as the other dimeric copper(II) carboxylates with apical nicotinamide and acetonitrile ligands. The molecules of 1 are linked with N–H···O and C–H···O hydrogen bonds. The π–π stacking interactions in 1 are observed between benzene rings of 2-nitrobenzoate anions and pyridine rings of nicotinamide and also between acetonitrile molecules and benzene rings of 2-nitrobenzoate anions. The C–H···O hydrogen-bonds and CH/π interactions are observed in crystal structure of 2.     

Synthesis and Crystal Structures of Methyl 3-(Benzoylamino)-6-methyl-2-oxo-2<Emphasis Type="Italic">H</Emphasis>-pyran-5-carboxylate and <Emphasis Type="Italic">N</Emphasis>-[5-(3,4-Dimethoxyphenyl)-6-methyl-2-oxo-2<Emphasis Type="Italic">H</Emphasis>-pyran-3-yl]benzamide

Abstract  

The compounds methyl 3-(benzoylamino)-6-methyl-2-oxo-2H-pyran-5-carboxylate (1), C₁₅H₁₃NO₅, and N-[5-(3,4-dimethoxyphenyl)-6-methyl-2-oxo-2H-pyran-3-yl]benzamide (2), C₂₁H₁₉NO₅, crystallize as a centrosymmetric hydrogen-bonded dimer facilitated by N–H···O interactions involving the amide and carbonyl moiety of the lactone group of adjacent molecules. Supramolecular aggregation in 1 is controlled by a combination of π–π interactions [centroid–centroid distance = 4.0745(11) ?] and weak C–H···O hydrogen bonding between the phenyl ring of the benzoylamino group and the carbonyl atom of the methoxycarbonyl group and in 2 by a combination of π–π interactions [centroid–centroid distance = 4.0699(8) and 4.1556(10) ?], weak C–H···O interactions between the methoxy substituents of the adjacent dimethoxyphenyl group and weak C–H··· π interactions.     

Synthesis,Structural and Thermal Studies of a New Nickel Complex Containing 2-Aminopyrimidine and Thiocyanate Mixed Ligands with a Three-Dimensional Network Structure

Abstract  

A new nickel(II) complex formulated as, trans-[Ni(amp)₂(SCN)₂(H₂O)₂]·2H₂O (1), (amp = 2-aminopyrimidine) has been synthesized and characterized by elemental analysis, IR spectroscopy, its molecular and crystal structures were determined by X-ray crystal structure analysis and its thermal stability by TGA/DTA methods. 1 is a neutral complex and the central atom sits on an inversion center and is coordinated by two endocyclic nitrogen atoms of two 2-aminopyrimidine heterocycles, two oxygen atoms of two water molecules and two nitrogen atoms of SCN⁻ ions. 2-aminopyrimidine molecules, thiocyanate ions and water molecules are in trans position. Thermal methods confirm two co-crystallized water molecules in 1. π–π stacking interactions and extensive O–H···O, O–H···N, O–H···S and N–H···N hydrogen bonds contribute to the formation of a three-dimensional supramolecular structure. Crystal data for complex at 120 K: triclinic, space group P-1, a = 7.2026(14), b = 7.8332(15), c = 9.0270(17) ?, α = 67.694(3), β = 72.732(4), γ = 77.012(4), Z = 1, R ₁ = 0.0323.     

Syntheses,Crystal Structures and Physical Properties of Cd(II) and Mn(II) Complexes with <Emphasis Type="Italic">Trans</Emphasis>-1,2-di(4-pyrindyl)ethylene and <Emphasis Type="Italic">P</Emphasis>-(carboxyl-methyloxy)-benzenecarboxylic Acid

Abstract  

Two complexes [Cd₂(dpe)₃(H₂O)₈]·(dpe)·(hssal)₂·(H₂O)₂ 1, [Mn(dpe)₂(Hpcmb)₂·(H₂O)₂] 2, (dpe = trans-1,2-di(4-pyrindyl)ethylene; H₂hssal = sulphosalicylic acid; H₂pcmb = p-(carboxyl-methyloxy)-benzenecarboxylic acid) has been prepared, and was characterized by elemental analysis, FT-IR and single-crystal X-ray diffraction. Structure indicates in complex 1 that Cd(II) is a distorted octahedral coordination geometry. The hssal²⁻ anions are localized between 2-D sheets {[Cd(dpe)₂(H₂O)₄]²⁺(dpe)}n and {{[Cd(dpe)₂(H₂O)₄]²⁺}n as count anions and bridge to further connect these 2-D sheets through hydrogen bond O–H···O to form 3-D structure. The complex 2 is a single molecule structure. In 2, Each Mn(II) atom is six-coordinated with a distorted octahedral coordination geometry. The single molecule units are extended into three-dimensional structure via π–π, hydrogen bonding interactions. The thermogravimetric behavior and luminescent property of complex 1 were investigated.     

Syntheses and Crystal Structures of Two Ferrocenyl Dicarboximides

Abstract  

Reactions of 1,1′-ferrocenedicarboxylic chloride with 2-aminopyrimidine and 2-aminopyrazine produce organometallic dicarboximides I and II, respectively. They crystallize in space groups F dd2 and P2₁/c, respectively. The molecules of I lying on twofold rotation axes are linked into a B-faced sheet by a C–H···O=C hydrogen bond [H····O = 2.46, C···O = 3.163(7) ? and C–H···O = 132°]. The sheets are linked into a layered structure by two types of weak C–H···O=C hydrogen bonds [H···O = 2.71, C···O = 3.340(8) ? and C–H···O = 126°; H···O = 2.69, C···O = 3.303(10) ? and C–H···O = 124°]. The molecules of II are linked into a centrosymmetric R ₂²(12) dimer by a C–H···O hydrogen bond [H···O = 2.40, C···O = 3.321(10) ? and C–H···O = 172°]. The dimers are further packed along the a axis by a C–H···O hydrogen bond [H···O = 2.69, C···O = 3.416(9) ? and C–H···O = 135°] to give an [100] double-chain. The double-chain is packed in the [010] direction by a C–H···O=C hydrogen bond [H···O = 2.69, C···O = 3.532(9) ? and C–H···O = 150°]. Further the intermolecular C–H···N hydrogen bond involving the cyclopentadienyl group as a hydrogen-bond donor and pyrazine N atom as an acceptor [H···O = 2.71, C···N = 3.536(10) ? and C–H···N = 148°] leads to a three-dimensional framework structure.     

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.     

Molecular Association of Almotriptan with Oxalate and Terephthalate Anions

Abstract  

Crystal structures of anti-migraine drug almotriptan were crystallized with oxalic acid (I) and with terephthalic acid (II) and their crystal structures and molecular associations were determined using X-ray diffraction methods. Crystals of both (I) and (II) are monoclinic, space group P2₁/c, with a = 5.6270(4) ?, b = 27.6419(19) ?, c = 13.6228(9) ?, β = 93.057(1)°, V = 2115.9(3) ?³, Z = 4 (I) and a = 13.3756(15) ?, b = 15.6065(17) ?, c = 10.7238(12) ?, β = 98.017(2)°, V = 2216.7(4) ?³, Z = 4 (II). In almotriptan oxalate {systematic name: N,N-dimethyl-2-[5-(pyrrolidin-1-ylsulfonyl-methyl)-1H-indol-3-yl]-ethanaminium semioxalate}, C₁₇H₂₆N₃O₂S⁺, C₂HO₄ ⁻, (I) and in almotriptan hemi terephthalate hydrate {systematic name: N,N-dimethyl-2-[5-(pyrrolidin-1-ylsulfonyl-methyl)-1H-indol-3-yl]-ethanaminium hemi terephthalate monohydrate}, C₁₇H₂₆N₃O₂S⁺, 0.5(C₈H₄O₄ ²⁻), H₂O, (II), both the almotriptan cations form a trimer with the corresponding anions via N–H···O hydrogen bonds. In (I), the oxalate salt is monoprotonated and in (II), the terephthalic acid is located across the inversion centre and exists as doubly protonated anion. In (I), the cation and anion are interlinked by the N–H···O and O–H···O hydrogen bonds into continuous two-dimensional layers generate an R₆⁶(34) hydrogen-bonded motif tetramers running parallel to the (0 0 1) plane. In (II), the cation and water form a centrosymmetric tetramer of R₄⁴(22) hydrogen-bonded motif via N–H···O and O–H···O hydrogen bonds and further cross-linked by centrosymmetric anions to form an infinite three-dimensional supramolecular hydrogen-bonded networks.     

5-Pyridine 4-yl-3H-(1,3,4) Oxadiazole-2 Thione Hydrochloride Monohydrate, (I), and 4 [5-Ethylsulfanyl)-(1,3,4) Thiadiazole-2-yl]-Pyridinium Perchlorate, (II)

Abstract  

The title compounds C₇H₈ClN₃O₂S, (I), and C₉H₁₀ClN₃O₄S_2, (II), both crystallize in monoclinic space group P2₁ /c with unit cell parameters (I) a = 7.9402(7), b = 10.6312(9), c = 11.7626(10), ?, β = 99.271(5)°, Z = 4 and (II) a = 5.1439(2), b = 9.0636(4), c = 27.1814 (7), ?, β = 95.116(2)°, Z = 4. In (I) the molecule consists of a 5-pyridine-4-yl group bonded to the carbon atom at the 5 position of (1, 3, 4) oxadiazole-2 thione hydrochloride monohydrate. The angle between the mean planes of the oxadiazole and pyridine rings is 9.6(6)°. Crystal packing in (I) is stabilized by strong N–H···O hydrogen bonds in concert with a solvent water molecule and weak O–H···Cl, O–H···S, N–H···Cl intermolecular interactions. The crystal structure of compound (II) consists of 4 [5-ethylsulfanyl)-(1, 3, 4) thiadiazole-2-yl]-pyridinium perchlorate, (C₉H₁₀N₃S₂)⁺(ClO₄)⁻, cation–anion pairs, containing strong intermolecular N–H···O hydrogen bonds and weak C–H···O and N–H···O intermolecular interactions operating between the ionic species that form a cooperative hydrogen-bonded, infinite chain O–H···O–H···O–H network which generates a sheet motif structure in the unit cell. It is also supported by weak intermolecular Cg···Cg π–π and Cl–O···Cg π-ring interactions which gives additional support to molecular packing stability in the unit cell. Geometry optimized MOPAC AM1 computational calculations on each compound provides support to the structural features in their respective crystal structures.     

Synthesis and Crystal Structure of a Novel Double-Chain Coordination Polymer [Zn<Subscript>2</Subscript>(bipy)<Subscript>2</Subscript>(btec)(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>]<Subscript>n</Subscript> (bipy = 2,2′-bipyridine; btec = 1,2,4,5-benzenetetracarboxylate)

Abstract  A novel aromatic polycarboxylate polymer, [Zn₂(bipy)₂(btec)(H₂O)₂]_n (1), has been synthesized and structurally characterized by the single crystal X-ray diffraction. Compound 1 belongs to the triclinic crystal system, space group P-1; a = 7.7449(6) ?, b = 8.9286(8) ?, c = 10.7422(8) ?, α = 80.95(1)°, β = 70.21(1)°, γ = 78.14(1)°, V = 680.93(10) ?³, Z = 2. The coordination geometry of Zn(II) atom is distorted trigonal bipyramidal with two nitrogen atoms of one 2,2′-bipy group, two oxygen atoms from two different btec ligands, and one water. The 16-membered rings are alternately arranged forming an infinite 1-D double-chain structure. A 3-D network was constructed by interlayer C···H–O, O···H–O hydrogen bonds and π–π stacking interactions. Compound 1 exhibits fluorescence at room temperature in the solid state. Graphical Abstract  A 1-D double-chain aromatic polycarboxylate polymer, [Zn₂(bipy)₂(btec)(H₂O)₂]_n (1), has been synthesized and structurally characterized by the single crystal X-ray diffraction. A 3-D network was constructed by intermolecular C···H–O, O···H–O hydrogen bonds and π–π stacking interactions. Compound 1 exhibits fluorescence at room temperature in the solid state.      

Synthesis and Crystal Structure of 1,3-Bis[2-(pyrrol-2-carbonyloxy)ethoxy]Benzene

Abstract  

A new compound, 1,3-bis[2-(pyrrol-2-carbonyloxy)ethoxy]benzene (1), was synthesized and characterized by X-ray diffraction. The crystal is monoclinic, space group P2₁/c with a = 6.3571(7), b = 11.0416(11), c = 28.156(3) ?, b = 92.821(2), V = 1974.0(4) ?³, Z = 4, Dc = 1.293 g/cm³, F(000) = 808, μ = 0.097 mm⁻¹. The final R = 0.0395 and wR = 0.0927 for 3478 observed reflections with I > 2 σ(I), and R = 0.0660 and wR = 0.1058 for all reflections. The title compound assembles into 2-D structure through a catemer type N–H⋯O hydrogen bonding motif and further forms 3-D structure through C–H···O hydrogen bonds.     

Hydrogen Bonded Supramolecular Assembly in N6-Benzyladeninium Nitrate and N6-Benzyladeninium 3-Hydroxy Picolinate: A Synthetic Cytokinin

Abstract  

N ⁶-benzyladeninium nitrate, (1), C₁₂H₁₂N₅ ⁺ NO₃ ⁻ crystallizes in P2 ₁/c, with a = 15.0035(13), b = 5.3788(5), c = 16.8954(13) ?, β = 107.331(6)°, Z = 4 and N ⁶-benzyladeninium 3-hydroxy picolinate, (2), C₁₂H₁₂N₅ ⁺ C₆H₄NO₃ ⁻, crystallizes in P1, with a = 8.3017(4), b = 14.6170(7), c = 14.7909 (8) ?, α = 78.801 (4), β = 81.979 (4),γ = 88.849 (4)°, Z = 4. In both the salts, the cation exists as N(7)H tautomer with protonation at the N₃ atom. The dihedral angle of 76.64 (16)° for (1), 67.91(12)° for (cation A) and 68.27 (13)° for (cation B) in (2), between the adenine plane and phenyl ring plane, the distal orientation of the N6 substituent with respect to the imidazole ring and the free N1 position, make these benzyladeninium cations meet all the requirements necessary for cytokinin activity. The crystal structures are stabilized by N–H···N, N–H···O, C–H···O hydrogen bonds and C–H···π stacking interaction between symmetry related benzyladenine molecule.     

Synthesis,Crystal Structure and Characterizations of New 3,4,7,8-Tetrachloro-1,10-Phenanthroline Zn(II) Complex

Abstract  

A novel 3,4,7,8-tetrachloro-1,10-phenanthroline (Cl₄phen) Zn(II) complex has been synthesized. The complex, [Zn(Cl₄phen)₂(H₂O)₂](NO₃)₂·CH₃CH₂OH (1), has been identified and characterized by single crystal X-ray diffraction, elemental analysis, FT-IR, thermogravimetric analysis and photoluminescence studies. Single crystal X-ray diffraction analysis reveals that complex (1) belongs to the monoclinic system, space group P2(1)/c, a = 10.061(2) Å, b = 18.924(4) Å, c = 18.189(4) Å, β = 100.94(3)°, and Z = 4. Complex (1) consists of cationic species [Zn(Cl₄phen)₂(H₂O)₂]²⁺, NO₃ ⁻ and CH₃CH₂OH. The zinc atom displays a distorted cis-N₄O₂ octahedral geometry. Via extended Zn–O–H···O–N–O···H–O–Zn bridge, every mononuclear unit is linked with other ones to form one-dimensional (1D) infinite chain of hydrogen bond system. Three-dimensional (3D) polymeric network arrangement was built via weak C–H···O and π-stacking interactions between Cl₄phen moieties. A solvent-dependency effect of complex (1) was observed in spectroscopic properties.     

Structures of two N-{2-([(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-halophenyl}acetamides

Abstract  

The compounds, N-{2-[(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-chlorophenyl}acetamide (1: X = Cl) and N-{2([(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-bromo-phenyl}acetamide (1: X = Br), are isostructural. The molecules are near ‘‘V’’ shaped with the angles between the two aromatic planes ca. 84° in each case. The various intermolecular interactions, namely N–H···O, N–H···N, N–H···F, and C–H···N hydrogen bonds and C–H···π, C–Cl···π and C–O···π interactions, generate 3-D arrays. Compound (1: X = Cl) crystallizes in the monoclinic space group P21/c with a = 16.9032(7) ?, 10.2193(4) ?, c = 7.5227(4) ?, β = 100.179(3)° and Z = 4. Compound (1: X = Br) crystallizes in the monoclinic space group P21/c with a = 17.2119(4) ?, 10.2167(2) ?, c = 7.5677(2) ?, β = 100.326(2)° and Z = 4.     

Hydrogen-Bonding in the Structures of the Hydrated Proton-Transfer Compounds of Isonipecotamide with the Isomeric Indole-2- and Indole-3-Carboxylic Acids

Abstract  

The structures of two hydrated proton-transfer compounds of 4-piperidinecarboxamide (isonipecotamide) with the isomeric heteroaromatic carboxylic acids indole-2-carboxylic acid and indole-3-carboxylic acid, namely 4-carbamoylpiperidinium indole-2-carboxylate dihydrate (1) and 4-carbamoylpiperidinium indole-3-carboxylate hemihydrate (2) have been determined at 200 K. Crystals of both 1 and 2 are monoclinic, space groups P2₁/c and P2/c, respectively with Z = 4 in cells having dimensions a = 10.6811(4), b = 12.2017(4), c = 12.5456(5) ?, β = 96.000(4)° (1) and a = 15.5140(4), b = 10.2908(3), c = 9.7047(3) ?, β = 97.060(3)° (2). Hydrogen-bonding in 1 involves a primary cyclic interaction involving complementary cation amide N–H···O(carboxyl) anion and anion hetero N–H···O(amide) cation hydrogen bonds [graph set R₂²(9)]. Secondary associations involving also the water molecules of solvation give a two-dimensional network structure which includes weak water O–H···π interactions. In the three-dimensional hydrogen-bonded structure of 2, there are classic centrosymmetric cyclic head-to-head hydrogen-bonded amide–amide interactions [graph set R₂²(8)] as well as lateral cyclic amide-O linked amide–amide extensions [graph set R₄²(8)]. The anions and the water molecule, which lies on a twofold rotation axis, are involved in secondary extensions.     

Order and Disorder in the Structures of Two Crystal Polymorphs of the Adduct Bis(Quinolinium-2-Carboxylate) DL-Malic Acid

Abstract  

The structures of two polymorphs of the anhydrous cocrystal adduct of bis(quinolinium-2-carboxylate) DL-malic acid, one triclinic the other monoclinic and disordered, have been determined at 200 K. Crystals of the triclinic polymorph 1 have space group P-1, with Z = 1 in a cell with dimensions a = 4.4854(4), b = 9.8914(7), c = 12.4670(8) ?, α = 79.671(5), β = 83.094(6), γ = 88.745(6)°. Crystals of the monoclinic polymorph 2 have space group P2₁/c, with Z = 2 in a cell with dimensions a = 13.3640(4), b = 4.4237(12), c = 18.4182(5) ?, β = 100.782(3)°. Both structures comprise centrosymmetric cyclic hydrogen-bonded quinolinic acid zwitterion dimers [graph set R₂²(10)] and 50% disordered malic acid molecules which lie across crystallographic inversion centres. However, the oxygen atoms of the malic acid carboxylic groups in 2 are 50% rotationally disordered whereas in 1 these are ordered. There are similar primary malic acid carboxyl O–H···O_{quinaldic acid} hydrogen-bonding chain interactions in each polymorph, extended into two-dimensional structures but in 1 this involves centrosymmetric cyclic head-to-head malic acid hydroxyl-carboxyl O–H···O interactions [graph set R₂²(10)] whereas in 2 the links are through single hydroxy-carboxyl hydrogen bonds.     

Structural and Spectroscopic Study of Cu(II) Pyridine-2,6-dicarboxylate Complex with 2-Ethylimidazole

Abstract  

A mononuclear copper(II) complex, [Cu(pydca)(2-Etlm)(H₂O)] (1) (H₂pydca = pyridine-2,6-dicarboxylic acid, 2-Etlm = 2-ethylimidazole), has been synthesized and characterized by elemental analyses, IR, UV–Vis, TG-DTA and single crystal X-ray diffraction. The complex 1 is in the orthorhombic crystal system, space group Pbca and Z = 8. The structural analysis indicated that Cu(II) center is five coordinated in a slightly distorted square pyramidal geometry by one N and two O atoms from a 2,6-pyridine dicarboxylate dianion, one N atom from a 2-ethylimidazole ligand, and one O atom from a aqua molecule. This mononuclear motif of 1 is further assembled to 3D supramolecular framework through strong O–H···O and N–H···O hydrogen bonding interactions.     

Crystal and Molecular Structure of Dichloro(ethylenediamine)gold(III) Nitrate: [Au(NH<Subscript>2</Subscript>CH<Subscript>2</Subscript>CH<Subscript>2</Subscript>NH<Subscript>2</Subscript>)Cl<Subscript>2</Subscript>]NO<Subscript>3</Subscript>

Abstract  The gold(III) atom in [Au(NH₂CH₂CH₂NH₂)Cl₂]NO₃ is chelated by the ethylenediamine (en) ligand and the approximately square planar geometry is completed by two chloride atoms. Weak Au···O and Au···Cl contacts are noted above and below the square plane leading to a tetragonally distorted octahedron for the gold(III) center. Extensive charge-assisted hydrogen bonding of the type N–H···O leads to the formation of a 2-D array and layers are consolidated into a 3-D network via C–H···O and C–H···Cl contacts. The compound crystallizes in the orthorhombic space group Pbca with a = 10.3380(11) ?, b = 8.2105(7) ?, c = 19.625(2) ?, and Z = 8. Index Abstract  Square planar complex cations form additional Au···O and Au···Cl interactions to form a tetragonally distorted octahedron for gold. The ionic components are connected into a 2-D array via charge-assisted N–H···O hydrogen bonding interactions.      

Supramolecular Aggregation in the 1:1 Co-crystal Formed Between Merocyanine Dye and 3-Nitrophenol,Characterized as a Hydrate

Abstract  The title organic salt comprises a (E)-4-[2-(4-hydroxyphenyl)vinyl]-1-methylpyridinium cation, a 3-nitro-phenoxide anion and a solvent water molecule of crystallisation. The anions and water molecules aggregate to form supramolecular chains facilitated by charge-assisted O–H···O hydrogen bonds and these form layers which are interspersed by layers of cations. Interactions between layers include O–H···O hydrogen bonding, as well as C–H···O and C–H···π contacts; π···π and C–H···O contacts are found within layers of cations. The compound crystallizes in the monoclinic space group P2₁/n with a = 15.018(7) ?, b = 7.328(2) ?, c = 17.571(7) ?, β = 112.342(15)°, and Z = 4. Index Abstract  A layer structure comprising alternating anions/water molecules and cations associated via charge-assisted O–H···O hydrogen bonding as well as C–H···O, C–H···π and π···π contacts is found in (II) .     

Synthesis,Crystal Structure and Optical Properties of a Three-Dimensional Supramolecule Assembled by a Dinuclear Neodymium Cluster

Abstract  

The reaction of isonicotinic acid (IN), sodium hydroxide, 1,10-phenanthroline (phen) and neodymium nitrate leads to the formation of a novel complex [Nd(phen)(IN)₂(NO₃)(H₂O)₂]₂ 1, which has been characterized by single crystal X-ray diffraction analysis: monoclinic, space group C2/c, with a = 24.93(2) Å, b = 9.452(3) Å, c = 21.406(5) Å, β = 97.87(2)°, and Z = 4. Complex 1 consists of a centrosymmetric dinclear molecule, and neodymium atoms are bridged by two carboxyl groups of two IN ligands. The dinuclear clusters of 1 are connected each other into a three-dimensional (3D) supramolecular framework, which is stabilized by O–H···O, O–H···N hydrogen bonds as well as π–π stacking interactions. Its electronic absorption and luminescence properties have also been investigated.