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This study reports a green and facile hydrothermal method to synthesis α-Fe2O3/BiPO4 composite and was used for photocatalytic application under visible light irradiation. The synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectrum (UV-Vis DRS), Fourier transform infrared (FT-IR) spectrum, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmet-Teller (BET) analysis and Photoluminescence (PL), which confirmed the formation of the composite. XRD analysis indicated that all the prepared samples present in pure hexagonal structure without Fe2O3 phases. The photocatalytic studies on methylene blue (MB) and ciprofloxacin (CIP) were evaluated under visible light irradiation and the α-Fe2O3/BiPO4 composite exhibited superior photocatalytic activity compared to the BiPO4. The results of PL studies substantiated that the enhancement of photocatalytic activity could be mainly attributed to the interaction of α-Fe2O3 and BiPO4 in the composite during photocatalysis which effectively improve electron-hole separation. The recyclability experiment corroborated the stability of α-Fe2O3/BiPO4 composite. Finally, the composite was converted into beads using calcium alginate, a non toxic biopolymer for easy separation of the catalyst from the reaction medium, which also showed equally good results. [ABSTRACT FROM AUTHOR]

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, C 4 H 8 N 3 O + ·Br - , (I), creatininium 3-aminobenzoate, C 4 H 8 N 3 O + ·C 7 H 6 NO 2 - , (II), and creatininium 3,5-dinitrobenzoate, C 4 H 8 N 3 O + ·C 7 H 3 N 2 O 6 - , (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 R 4 2 (8) and R 4 2 (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 R 2 2 (8), R 2 1 (7) and R 2 1 (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.

Two new crystalline solids, namely, 5-aminotetrazole-3,5-dihydroxybenzoic acid-water (1/4/6), CH 3 N 5 ·4C 7 H 6 O 4 ·6H 2 O (I), and 5-aminotetrazolium 3,5-dinitrosalicylate, CH 4 N 5 + ·C 7 H 3 N 2 O 7 - (II), have been synthesized and characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. The crystal packing arrangements of I and II are governed by N-H...O and O-H...O hydrogen-bonding interactions. In cocrystal I, adjacent acid molecules are linked through O-H...O hydrogen bonds, forming a dimer with an R 2 2 (8) motif. In salt II, the tetrazolium cation and acid anion are linked through N-H...O hydrogen bonds to also form a dimer with an R 2 2 (8) motif. Further N-H...O and O-H...O hydrogen bonds help to stabilize the crystal packing, along with aromatic π-π stacking interactions in I and carbonyl...π interactions in II. The Hirshfeld surface analysis and fingerprint plots reveal that O...H/H...O interactions contribute 34.4% of the total interactions in the crystal packing of cocrystal I and 36.7% in salt II.

Two new crystalline salts, namely, hypoxanthinium bromide monohydrate, C 5 H 5 N 4 O + ·Br - ·H 2 O ( I ) and xanthinium bromide monohydrate, C 5 H 5 N 4 O 2 + ·Br - ·H 2 O ( 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 ) ., (© Sathya et al. 2022.)

Two salts of 1,9-di-hydro-purin-6-one (hypoxanthine), namely, 6-oxo-1,9-di-hydro-purin-7-ium 5-sulfosalicylate dihydrate, C 5 H 5 N 4 O + ·C 7 H 5 O 6 S - ·2H 2 O, ( I ), and 6-oxo-1,9-di-hydro-purin-7-ium perchlorate monohydrate, C 5 H 5 N 4 O + ·ClO 4 - ·H 2 O, ( 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 )., (© Sathya et al. 2022.)

The asymmetric unit of the title coordination polymer [Zn(C 9 H 6 NO 2 ) 2 (C 10 H 8 N 4 )] n , consists of one Zn II cation, one bidentate 1 H -indole-5-carboxyl-ate (I5C) anion and half of a 4,4'-azobi-pyridine (Abpy) neutral ligand. In the coordination polyhedron, the Zn II 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., (© Sathya et al. 2021.)

The title compound, C 6 H 2 N 3 O 7 - ·C 10 H 13 Cl 2 N 2 + , crystallizes with one 1-(2,3-di-chloro-phen-yl)piperazine (DP) cation and one picrate (PA) anion in the asymmetric unit. In the crystal structure, the DP cation and PA anion are inter-connected via several N-H⋯O and C-H⋯O hydrogen bonds. The DP cation and PA anion are further connected through C-Cl⋯π [3.8201 (4), 3.7785 (4) Å] and N-O⋯π [3.7814 (4) Å] inter-actions. The DP cations are further inter-connected via a weak inter-molecular Cl⋯Cl [3.2613 (4) Å] halogen-halogen inter-action. The combination of these supra-molecular inter-actions leads to a herringbone like supra-molecular architecture., (© Sathya et al. 2021.)