A study of the crystal structures, supra-molecular patterns and Hirshfeld surfaces of bromide salts of hypoxanthine and xanthine.

Two new crystalline salts, namely, hypoxanthinium bromide monohydrate, C5H5N4O+·Br-·H2O (I) and xanthinium bromide monohydrate, C5H5N4O2 +·Br-·H2O (II), were synthesized and characterized by single-crystal X-ray diffraction technique and Hirshfeld surface analysis. The hypoxanthinium and xanthinium cations in salts I and II are both in the oxo-N(9)-H tautomeric form. The crystal packing of the two salts is governed predominantly by N-H⋯O, N-H⋯Br, C-H⋯Br and O-H⋯Br inter-actions described by R 2 3(9) and R 2 2(8) synthons. The crystal packing is also consolidated by carbon-yl⋯π inter-actions between symmetry-related hypoxanthinium (HX+ ) cations in salt I and xanthinium cations (XA+ ) in salt II. The combination of all these inter-actions leads to the formation of wave- and staircase-like architectures in salts I and II, respectively. The largest contributions to the overall Hirshfeld surface are from Br⋯H/H⋯Br contacts (22.3% in I and 25.4% in II) .

Crystal structures and Hirshfeld surface analyses of hypoxanthine salts involving 5-sulfosalicylate and perchlorate anions.

Two salts of 1,9-di-hydro-purin-6-one (hypoxanthine), namely, 6-oxo-1,9-di-hydro-purin-7-ium 5-sulfosalicylate dihydrate, C5H5N4O+·C7H5O6S-·2H2O, (I), and 6-oxo-1,9-di-hydro-purin-7-ium perchlorate monohydrate, C5H5N4O+·ClO4 -·H2O, (II), have been synthesized and characterized using single-crystal X-ray diffraction and Hirshfeld analysis. In both salts, the hypoxanthine mol-ecule is protonated at the N7 position of the purine ring. In salt (I), the cation and anion are connected through N-H⋯O inter-actions. The protonated hypoxanthine cations of salt (I) form base pairs with another symmetry-related hypoxanthine cation through N-H⋯O hydrogen bonds with an R 2 2(8) ring motif, while in salt (II), the hypoxanthine cations are paired through a water mol-ecule via N-H⋯O and O-H⋯N hydrogen bonds with an R 3 3(11) ring motif. The packings within the crystal structures are stabilized by π-π stacking inter-actions in salt (I) and C-O⋯π inter-actions in salt (II). The combination of several inter-actions leads to the formation of supra-molecular sheets extending parallel to (010) in salts (I) and (II). Hirshfeld surface analysis and fingerprint plots reveal that O⋯H/H⋯O contacts play the major role in the crystal packing of each of the salts, with a 54.1% contribution in salt (I) and 62.3% in salt (II).

Synthesis, crystal structure determination and Hirshfeld surface analysis of three new salt forms of creatinine with hydrobromic acid, 3-aminobenzoic acid and 3,5-dinitrobenzoic acid.

Creatinine, a biologically important compound, is used to analyze kidney function and kidney diseases in the human body. The salt form of creatinine is used in the formation of drug materials like anti-HIV, antifungal, antiprotozoal, antiviral and antitumour compounds. Here we report the solid-state structures of three new crystalline salts, namely, creatininium (2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium) bromide, C4H8N3O+·Br-, (I), creatininium 3-aminobenzoate, C4H8N3O+·C7H6NO2-, (II), and creatininium 3,5-dinitrobenzoate, C4H8N3O+·C7H3N2O6-, (III). These salts have been synthesized and characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. The structural chemistry of salts (I)-(III) and their crystal packing are discussed in detail. The primary interaction between the creatinine cation and the acid anion in the three salts is N-H...Br/O hydrogen bonds. In salt (I), the creatinine cation and bromide anion are connected through a pair of N-H...Br hydrogen bonds forming R42(8) and R42(12) ring motifs. In salts (II) and (III), the creatinine cation interacts with the corresponding anion via a pair of N-H...O hydrogen bonds. The crystal structure is further stabilized by C-H...O and O-H...O hydrogen bonds with the ring motifs R22(8), R21(7) and R21(6). Furthermore, the crystal structures are stabilized by π-π, C-H...π, C-O...π and N-O...π stacking interactions. The contributions made by each hydrogen bond in maintaining the crystal structure stability has been quantified by Hirshfeld surface analysis.

Fused ring effect on optical nonlinearity and structure property relationship of anthracenyl chalcone based push-pull chromophores.

The Ultraviolet-visible (UV-Vis) spectra indicate that anthracenyl chalcones (ACs) have high maximum wavelengths and good transparency windows for optical applications and are suitable for optoelectronic applications owing to their HOMO-LUMO energy gaps (2.93 and 2.76 eV). Different donor substituents on the AC affect their dipole moments and nonlinear optical (NLO) responses. The positive, negative, and neutral electrostatic potential regions of the molecules were identified using molecular electrostatic potential (MEP). The stability of the molecule on account of hyperconjugative interactions and accompanying charge delocalization was analyzed using natural bond orbital (NBO) analysis. Open and closed aperture Z-scans were performed using a continuous-wave frequency-doubled diode-pumped solid-state (DPSS) laser to measure the nonlinear absorption and nonlinear refractive index coefficients, respectively. The valley-to-peak profile of AC indicated a negative nonlinear refractive index coefficient. The obtained single crystals possess reverse saturation absorption due to excited-state absorption. The structural and nonlinear optical properties of the molecules have been discussed, along with the role of anthracene substitution for enhancing the nonlinear optical properties. The calculated third-order susceptibility value was 1.10 x10-4 esu at an intensity of 4.1 kW/cm2, higher than the reported values for related chalcone derivatives. The NLO response for both ACs offers excellent potential in optical switching and limiting applications.

catena-Poly[[bis-(1H-indole-5-carboxyl-ato-κ2 O,O')zinc(II)]-µ-4,4'-azobi-pyridine-κ2 N 1:N 1'].

The asymmetric unit of the title coordination polymer [Zn(C9H6NO2)2(C10H8N4)] n , consists of one ZnII cation, one bidentate 1H-indole-5-carboxyl-ate (I5C) anion and half of a 4,4'-azobi-pyridine (Abpy) neutral ligand. In the coordination polyhedron, the ZnII ion adopts a distorted octa-hedral geometry. The coordination polymer is stabilized by a combination of N-H⋯O and C-H⋯π inter-actions, which leads to the formation of wave-like two-dimensional coordination polymeric layers.

Redetermination of the crystal structure of 2-oxo-1,3-thia-zolidin-4-iminium chloride.

In the redetermination of the title compound, C3H5N2OS+·CI-, the asymmetric unit consists of one independent 2-oxo-1,3-thia-zolidin-4-iminium cation and one independent chloride anion. The cation inter-acts with a chloride anion via N-H⋯Cl hydrogen bonds forming a supra-molecular chain along [010]. These supra-molecular chains are further extended by weak C-H⋯Cl and C-H⋯O inter-actions, forming a two-dimensional network parallel to (001). The crystal structure is further stabilized by weak C-O⋯π inter-actions, supporting a three-dimensional architecture. The structure was previously determined by Ananthamurthy & Murthy [Z. Kristallogr. (1975). 8, 356-367] but has been redetermined with higher precision to allow the hydrogen-bonding patterns and supra-molecular inter-actions to be investigated.

Multiple N-H···NC, C-H···NC and nitrile···π interactions in 4,4'-bipyridine-1,1'-diium bis(1,1,3,3-tetracyano-2-ethoxypropenide): structure determination and DFT calculations of anion···π cation interaction energies.

Polynitrile anions are important in both coordination chemistry and molecular materials chemistry, and are interesting for their extensive electronic delocalization. The title compound crystallizes with two symmetry-independent half 4,4'-bipyridine-1,1'-diium (bpyH2(2+)) cations and two symmetry-independent 1,1,3,3-tetracyano-2-ethoxypropenide (tcnoet(-)) anions in the asymmetric unit. One of the bpyH2(2+) ions is located on a crystallographic twofold rotation axis (canted pyridine rings) and the other is located on a crystallographic inversion center (coplanar pyridine rings). The ethyl group of one of the tcnoet(-) anions is disordered over two sites with equal populations. The extended structure exhibits two separate N-H···NC hydrogen-bonding motifs, which result in a sheet structure parallel to (010), and weak C-H···NC hydrogen bonds form joined rings. Two types of multicenter CN···π interactions are observed between the bpyH2(2+) rings and tcnoet(-) anions. An additonal CN···π interaction between adjacent tcnoet(-) anions is observed. Using density functional theory, the calculated attractive energy between cation and anion pairs in the tcnoet(-)···π(bipyridinediium) interactions were found to be 557 and 612 kJ mol(-1) for coplanar and canted bpyH2(2+) cations, respectively.

(Dibenzyl sulfoxide-kappa O)bis(1,3-diphenylpropane-1,3-dionato-kappa(2)O,O')dioxouranium(VI).

In the title compound, [UO(2)(C(15)H(11)O(2))(2)(C(14)H(14)OS)], the U(VI) atom is coordinated by seven O atoms in a distorted pentagonal-bipyramidal geometry. Both diphenylpropane-1,3-dionate systems are nearly planar. The sulfoxide moiety is in a distorted tetrahedral geometry, while its two aromatic rings are nearly orthogonal to one another. The crystal packing is stabilized by two bifurcated hydrogen-bonding interactions involving both uranyl O atoms.

Bis[1,1'-bis(diphenylphosphino)ferrocenium] hexadecachlorotetraantimony(III) ethanol solvate.

In the title compound, [Fe(C(17)H(14)P)(2)](2)[Sb(4)Cl(16)] x C(2)H(6)O, the Fe atoms lie on inversion centres and the pairs of cyclopentadienyl rings are consequently in a fully staggered conformation. The centrosymmetric anionic clusters formed by [Sb(4)Cl(16)](4-) are surrounded by the cations and are held together by weak C-H...Cl interactions. These formations stack along the a axis to form columns, and the columns are interconnected by another weak C-H...Cl interaction along the b axis.