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Stability constants for the binary (1 : 1) complexes of CoII, NiII, CuII, ZnII, CdII, CaII, SrII and BaII with cytosine, cytidine, 5-bromocytosine, 5-azacytosine and 5-fluorocytosine were determined in aqueous solution (Ionic strength, μ = 0.1 mol dm -3 NaNO 3 ) potentiometrically at 25, 35 and 45°C. Experimental pH titration data were analyzed using the BEST computer program in order to evaluate formation constants of various intermediate species formed in the above binary systems. Enthalpy and entropy changes for the formation of binary complexes were calculated. On the basis of solution studies, efforts were made to prepare the binary complexes with 5-azacytosine ligand. Isolated solid complexes were characterized by different techniques and spectroscopic studies suggested a polymeric nature for the complexes, with OH and 5-azacytosine acting as bridging ligands. [ABSTRACT FROM AUTHOR]

Cations and anions of the title compound {systematic name: 1-[4-(amino­carbonyl)butyl]guanidinium bis­(hydrogen­squarate)}, C6H17N5O2+·2C4HO4−, are connected into a three-dimensional network by inter­molecular N—H⋯O hydrogen bonds between thel-argininamidium ammonium, amide and guanidinium functions and the hydrogensquarate carbonyl O atoms. The independent hydrogensquarate monoanions are linked into dimers by pairs of O—H⋯O′ hydrogen bonds. [ABSTRACT FROM AUTHOR]

Abstract: This work describes the synthesis and characterization of two Pd(II) complexes [(3,5-Hdmpz)2Pd2(μ-3,5-dmpz)2(2,6-dipic)] (1) and [Na2(H2O)4Pd(2,6-dipic)2] (2) (3,5-Hdmpz=3,5-dimethylpyrazole and 2,6-dipic=2,6-pyridinedicarboxylate). The X-ray molecular structure determination shows that 1 is a binuclear complex bridged by two 3,5-dmpz units and is completely unsymmetric since one palladium atom contains two protonated 3,5-Hdmpz ligands and the other one contains the 2,6-dipic2− unit that coordinates in a bidentate fashion. The central six-member Pd2N4 core shows a boat-like conformation where the palladium atoms are positioned at the vertices of the boat. The molecules are assembled in an extended zigzag one-dimensional network formed through 3,5-Hdmpz-carboxylate (2,6-dipic2−) hydrogen bonds. The packing of complex 2 is constructed of cationic Na+–H2O and anionic Pd-2,6-dipic2− units joined together to form an extended two dimensional network. Alternate short and long Na–Na distances are observed in the cationic layer. A detailed quantum-chemical calculation on the Na-chains in 2 has been made. Complex 1 shows a luminescence property and antimicrobial activity against Bacillus subtilis, Escherichia coli and Aspergillus niger where the MIC has been found to be 100μg/mL for all three species. [Copyright &y& Elsevier]

Abstract: Two hydrogen-bonded palladium(II) and platinum(II) complexes, [Pd(Hida)2] (1) and [Pt(Hida)2] (2) (Hida− =iminodiacetate), have been synthesized and characterized by single crystal X-ray diffraction analyses. Hida− serves as a bidentate ligand coordinating to both Pd(II) and Pt(II) through its nitrogen and oxygen atom, exhibiting a square planar geometry with a trans configuration. The uncoordinated carboxylic group and the imino group of the ligand are involved in strong intermolecular hydrogen bonding to form a two dimensional layered network in both the complexes. The network is propagated along the ac-plane and stacks orthogonally to the b-axis. The thermogravimetric analyses for complexes 1 and 2 reveal stepwise decomposition processes indicating the probable decarboxylation of the free and bonded carboxylates. As there are two types of hydrogen bonding (N–H⋯O, O–H⋯O) present in both the complexes, two endothermic peaks regarding heat change are evident from their DSC diagrams. [Copyright &y& Elsevier]

The article presents information on the structure of the organic compound S-Phenyl 4-cyanothiobenzoate or C14H9NOS. The molecules of this compound exhibit a chiral non-planar structure in which the 4-cyanophenyl and S-phenyl rings are tilted at dihedral angles of 1.81 (2) and 72.49 (1)° with respect to the central thiocarbonate unit. The compound crystallizes in the non-centrosymmetric monoclinic space group P21 and participates in very weak intermolecular hydrogen bonds and its observed structure is in good agreement with those determined for other S-phenyl thiobenzoates.

A series of linear diimine and diamine-bridged binuclear dioxomolybdenum(VI) complexes having general formula [(MoO 2 L) 2 (B-B)] [where, B-B is a bridging linear N,N′-bidentate spacer 4,4′ bipyridine, 1,2 bis (4-pyridyl) ethene and 1,2 bis (4-pyridyl) ethane] with the tridentate binegative Schiff base ligands obtained by the condensation of salicylaldehyde/2-hydroxyacetophenone with S-benzyl/S-methyl dithiocarbazate have been synthesized. Elemental analysis, various spectroscopic (IR, UV–Vis, 1 H NMR) measurements and electrochemical studies have been used for characterization of these complexes. The complexes 2 , 2a , 9 and 10 were structurally characterized by single crystal X-ray crystallography which reveal that in these complexes the overall coordination geometry around the Mo(VI) center can be described as distorted octahedral. Complexes 2 , 2a , 9 and 10 give rise to interesting supramolecular architectures via hydrogen bonding and π - π stacking interactions. In addition, extensive hydrogen bonding interactions in complex 10 lead to the formation of cavities. DFT calculations on the ligand and complexes 2 , 2a , 9 and 10 were also carried out. [ABSTRACT FROM AUTHOR]

The title compound, [Ir(η5-C5Me5)Cl(en-κ2 N)](CF3SO3) (en is ethylenediamine) or [Ir(C10H15)Cl(C2H8N2)](CF3SO3), contains a half-sandwich (η5-C5Me5)IrIII fragment coordinated in a bidentate manner by the N atoms of an en ligand. N—H...O hydrogen bonds between the en amino groups and O atoms of the trifluoromethanesulfonate anions generate polymeric chains. The cation and anion both have C s symmetry. The C atoms of the en ligand are disordered about a mirror plane. The crystal structure involves N—H...O, C—H...O and N—H...Cl hydrogen bonds. [ABSTRACT FROM AUTHOR]

The title compound, [Ir(η5-C5Me5)(dien-κ3 N)](CF3SO3)2 (dien is diethyl­enetriamine) or [Ir(C10H15)(C4H13N3)](CF3SO3)2, contains a half-sandwich (η5-C5Me5)IrIII fragment coordinated in a facial manner by the N atoms of a dien ligand. N—H⋯O hydrogen bonds to the trifluoro­methane­sulfonate counter-anions link the organometallic cations into a chiral polymeric network. [ABSTRACT FROM AUTHOR]

Mol­ecules of the title compound, C9H11NO, are connected into infinite chains by inter­molecular N—H⋯O hydrogen bonds of length 2.893 (3) Å between the N-methyl­amino and carbonyl functions. [ABSTRACT FROM AUTHOR]

Cations of the title compound, 1-carbamoyl-2-(4-hydroxy­phen­yl)ethyl­ammonium chloride monohydrate, C9H13N2O2+·Cl−·H2O, are connected by inter­molecular N—H⋯O [N⋯O = 2.905 (3) Å] hydrogen bonds between the amide and 4-hydr­oxy functions into helical chains propagating along the [010] axis. The Cl− ions and water O atom participate in a complex pattern of hydrogen bonds to link these ribbons into a three-dimensional network. [ABSTRACT FROM AUTHOR]

We report the synthesis, spectroscopic and structural elucidation of two prolinamide derivatives of squaric acid, i.e. prolinamide ester amide of squaric acid ethyl ester (1) and prolinamide diamide of squaric acid dihydrate (2). Both compounds crystallize in non-centrosymmetric space groups, monoclinic P21 (1) and orthorhombic P212121 (2), respectively. For first time in the literature the crystal structure of homodiamide of amino acid amide of squaric acid is reported. The data for heterodiamides is also absent. Supramolecular zig-zag chains by hydrogen bonds of H2N–C=O⋯HNH (3.020 Å) and HNH⋯O=C(Sq) (2.972 Å) types with the participation of amide and squaric acid (Sq) fragments, –C=O–NH2 and O=C(Sq) are refined in (1). A helix supramolecular structure is formed in (2) by moderate intermolecular HNH⋯O=C(NH2) hydrogen bond with length of 2.947 Å. The two crystallographical non-equivalent water molecules stabilized the helix by interactions of types HOH⋯O=C(Sq) (2.917 Å), HOH⋯O=C(NH2) (2.899 Å), H2O⋯NH2(C=O) (2.972 Å), respectively. Optical and magnetic properties are investigated with a view to explain the correlation structure-properties of the newly synthesized molecules. [Copyright &y& Elsevier]

Abstract: (E)-4-(Hydroxyiminomethyl)-pyridinium hydrogenoxalate (1) and bis((E)-4-(hydroxyiminomethyl)-pyridinium) squarate (2) were synthesized and their crystal structures determined by means of single crystal X-ray diffraction. The structures of (1) and (2) consist of infinite layers and chains, respectively, formed by (1): N–H···O (2.852(2), 2.827(2)Å) and O–H···O (2.665(2)Å) and (2): N–H···O (2.620(2)Å) and O–H···O (2.600(1)Å) intermolecular hydrogen bonds between the cations and anions. Hydrogenoxalate ions form chains within the infinite layers by strong interanionic O–H···O interactions (2.583(2)Å). Antiperiplanar conformations of the cations for (1) and (2) (CCOH) dihedral angle of 178.9(1)° (1) and 179.4(1)° (2) are observed. Spectroscopic properties both in solution and in the solid state were elucidated by means of 1H- and 13C-NMR, UV-spectroscopy and conventional and linear polarized IR- (IR-LD) spectroscopy. Quantum chemical calculations at the DFT, MP2 and CIS level of theory and the 6-31++G∗∗ basis set were employed for predicting and supporting experimentally observed optical propertied and electronic structures of the protonated (E)-4-(hydroxyiminomethyl)-pyridine. [Copyright &y& Elsevier]

Abstract: The title compound was synthesized and characterized by single crystal X-ray diffraction and solid-state polarized IR-spectroscopy of oriented colloids in a nematic host. The compound crystallizes in the monoclinic space group P21/c and its structure consists of a 3D supramolecular network of tyrammonium cations, water and sulfate anions directed by intermolecular hydrogen bonding interactions. Two non-equivalent tyrammonium cations are observed with pseudo T and T trans configurations, respectively. The vibrational characteristics of the non-equivalent molecules are assigned using solid-state polarized IR-spectroscopy. The structural and spectroscopic data are compared with theoretical calculations at the MP2/6-31++G∗ level of theory and basis set using the tyrammonium cation heptahydrate as a model system. [Copyright &y& Elsevier]

Abstract: The novel, 1-methyl-4-[2-(4-hydroxyphenyl)ethenyl]pyridinium dihydrogenphosphate salt was synthesized and its structure and properties elucidated spectroscopically, thermally and structurally, using single crystal X-ray diffraction, linear-polarized solid-state IR spectroscopy (IR-LD), UV–vis spectroscopy, TGA, DSC, DTA and MS. The compound crystallizes in the monoclinic P21/c space group and exhibits a pseudo layer structure with molecules linked by strong OH⋯O–P intermolecular hydrogen bonds of length 2.593Å. The dihydrogenphosphate anions themselves form infinite chains through strong OH⋯O–P intermolecular hydrogen bonds of lengths 2.636 and 2.658Å. The crystallographic disorder of these systems and its effect on IR-LD spectra in the solid state are discussed. Solutions of different polarity show a significant CT band shift of up to 70nm, corresponding to a molecular first hyperpolarizability value. [Copyright &y& Elsevier]

Abstract: Benzamidinium d-glucuronate (1) crystallizes in the orthorhombic space group P212121 and exhibits a 3D network with molecules linked by moderate intermolecular hydrogen bonds (HNH…O(solvent) 2.993Å, HNH…OCO 2.894Å, HNH…O(cycle) 2.844Å, OH…NH2 2.931Å, OH…O(solvent) 2.894, 2.924 and 2.715Å (stronger)) with participation of cations, anions and solvent molecules. The IR-band assignment of carbohydrate moieties is elucidated by a comparison between the types and bond lengths of intermolecular interactions with participation of OH groups in d-glucuronate and linear polarized IR-(IR-LD) spectroscopic data. Experimental results are supported by theoretical ab initio calculations of benzamidinium cation and d-glucuronate anion. [Copyright &y& Elsevier]

The components of the title compound, C6H14N+·C4HO4-·- 0.5H2O, are connected by moderate intermolecular N—H⋯O hydrogen bonds between the anions and cations into infinite three-dimensional networks. The cyclohexylammonium cation interacts with the solvent molecule by means of an N—H⋯O hydrogen bond. The hydrogensquarate anions form α chains through strong O—H⋯O interactions. [ABSTRACT FROM AUTHOR]

Abstract: This work describes the synthesis and X-ray crystallographic characterization of three nickel(II) complexes [Ni(3,2,3-tet){Ag(CN)2}2] (1), [Ni(3,2,3-tet)(μ-tp)] n ·1.5nH2O (2) and {[Ni(3,2,3-tet)(μ1,5-dca)](ClO4)} n (3) where 3,2,3-tet= N,N′-bis(3-aminopropyl)-1,2-ethylenediamine, tp=terephthalate and dca=dicyanamide. Compound 1 is a heterotrinuclear discrete distorted octahedral molecule whereas compound 2 forms a 1D polymeric network and an extended 2D network is formed by intermolecular hydrogen bonding. Interestingly, two adjacent 1D chains execute a novel double-helical network constructed by Ni(II) and the bridging dca ligand in compound 3. The variable temperature magnetic susceptibility measurements for compounds 2 and 3 were also carried out. [Copyright &y& Elsevier]

The title compound, 2C9H8NO2+·C4O42−, contains a dianion with approximately D4 h symmetry [C—C = 1.465 (4)–1.470 (4) Å and C—O = 1.248 (4)–1.264 (4) Å]. Individual dianions are linked to four neighbouring 8-hydroxy­quinolinium cations by O⋯H—N [2.666 (4) and 2.681 (4) Å] and O⋯H—O [2.596 (3) and 2.605 (3) Å] hydrogen bonds to generate a polymeric chain. [ABSTRACT FROM AUTHOR]

Molecules of syring­aldehyde, C9H10O4, are connected by intermolecular O—H⋯O [H⋯O = 2.05 Å and O⋯O = 2.713 (2) Å] hydrogen bonds between the 4-hydroxy and 1-aldehyde functions into infinite linear chains. The 4-hydroxy H atoms also participate in an intramolecular O—H⋯O [H⋯O = 2.22 Å and O⋯O = 2.662 (2) Å] interaction with a neighbouring methoxy O atom. [ABSTRACT FROM AUTHOR]

Mol­ecules of the title compound, 2-(2-eth­oxy-3,4-dioxocyclo­butenylamino)-2-[2-(methyl­sulfan­yl)eth­yl]acetamide, C11H16N2O4S, are connected into chains in the [010] direction by inter­molecular N—H⋯O hydrogen bonds involving thel-methio­ninamide N atoms and its carbonyl O atom. [ABSTRACT FROM AUTHOR]

Cations of the title compound, C5H11N2O+·C4HO4−, are connected by inter­molecular N(amide)— H⋯O(amide) hydrogen bonds into helical chains, whereas anions are inter­linked by strong O(hydrox­yl)—H⋯O hydrogen bonds into chains. These two distinct chains are interconnected by both N(amide)—H⋯O and N(ammonium)—H⋯O hydrogen bonds into a three-dimensional framework. One of the ammonium protons is involved in a three-centre hydrogen bond. [ABSTRACT FROM AUTHOR]