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The reaction of copper (II) nitrate with pyridine-2,6-dicarboxylic acid, (pydcH₂) and 2,2'-bipyridine (2,2'-bipy) led to the formation of the title compound, [Cu(C₇H₄NO₄)(C₁₀H₈N₂)(H₂O)]NO₃.H₂O, or [Cu(pydcH)(2,2'-bipy)(H₂O)]NO₃.H₂O. The crystal system of the complex is triclinic with space group P and two molecules per unit cell. The unit cell parameters are: a = 7.0438 (6) Å, b = 11.3215 (10) Å, c = 12.9148 (9) Å, α = 107.498 (4)°, β = 94.557 (5)° and  g = 104.325 (5)°. The final R value was 0.03 for 3601 observed reflections. The cationic complex features six-coordinate Cu^II with a distorted octahedral geometry with a significantly longer Cu1—O4 bond [2.5491(16) Å]. Considerable C═O···π stacking interactions between the C═O groups with distance of 3.498 (2) Å are observed. In addition, distinct intermolecular O—H···O and N—H···O hydrogen bonds lead to the formation of R(12) and C(12) graph sets motifs. In the crystal structure, a wide range of non-covalent interactions consisting of hydrogen bonding (O—H···O, O—H···N and C—H···O), π–π [centroid–centroid distances of 3.5193 (13) Å and 3.6876 (13) Å] and C═O···π stacking interactions connect the various components into a supramolecular structure.

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The title compound (C₁₀H₉N₂)[Cr(C₆H₇NO₆)₂](C₁₀H₈N₂)∙2H₂O or (4,4´-bipyH)[Cr(ntaH)₂](4,4´-bipy)∙2H₂O (ntaH₃ is nitrilotriacetic acid) was synthesized by reaction of Cr(NO₃)₃∙9H₂O with 4,4´-bipyridine, and nitrilotriacetic acid with 4:2:1 molar ratio in aqueous solution. The crystal structure of this complex was identified using X-ray crystallography. The unit cell parameters are as follows:

a = 9.8501(3) Å, b = 13.157(2) Å, c = 26.842(4) Å, β = 104.807(7)°.

The final R value is 0.041 for 7747 independent reflections. The title compound crystallized in monoclinic system and belongs to P2₁/c space group.  The central Cr^III atom is coordinated by two tridentaid (ntaH₂) ligands and the resulted CrO4N2 set can be described as distorted octahedral geometry. The asymmetric unit contains two half of anionic complex, one 4, 4´-bipyridiniom ion, (4, 4´-bipyH)⁺, one neutral 4, 4´-bipyridine molecule and two non-coordinated water molecules. Intramolecular hydrogen bonds, π-π [centroid –centroid distances of 3.674 Ǻ], C-H…π, O-H…π and N-H…π stacking interactions [with distance of 3.714, 3.736 and 3.270 Å respectively], connect the various components into a supramolecular structures.

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The polymeric compound, {(C₁₀H₉N₂)[Mn(C₇H₃NO₄)₂].­(C₁₀H₈N₂).6H₂O}_n, was prepared by the reaction of manganese (II) nitrate with pyridine-2,3-dicarboxylic acid, (py-2,3-dcH₂) and 4,4'-bipyridine (4,4'-bipy) in a 1:2:4 molar ratio. The crystal system of the complex is monoclinic with space group P2₁/n and four molecules per unit cell. The unit cell parameters are: a = 22.2099(15) Å, b = 6.6599(4) Å,
c = 23.5921(16) Å and β = 104.014(3)­°.  The final R value was 0.04 based on 8960 reflections. The central atom is attached to two (py-2,3-dc)^2– ligands through their N and O atoms in a planar square arrangement and two O atoms from bridging carboxylate groups, forming polymeric chains. So, the anionic complex features six-coordinate Mn (III) with a distorted octahedral geometry. In the crystal structure, a wide range of non-covalent interactions consisting of hydrogen bonding (of the types O−H···O, O−H···N and C−H···O), ion pairing, and π–π (centroid-centroid distances of 3.607 and 3.721 Å), C−H···π (with H···π distance of 2.941 Å) and C=O···π (with O···π distances of 2.943, 3.702 and 3.743 Å)  stacking interactions stabilize the supramolecular structure.

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9-aminoacridinum acridine-9-carboxylate (1) as a proton transfer ion pair was obtained by the reaction of 9-aminoacridine, acridine-9-carboxylic acid and zinc nitrate (1:1:1 molar ratio) in solvents mixture H₂O/MeOH under reflux condition. The crystal structure of this compound was determined by elemental analysis, IR spectroscopy and single crystal X-ray diffraction method. Crystallographic data for 1 was collected at 100 K.  The synthesized compound has been crystallized in monoclinic system with C2/c space group and a = 15.336 (9), b = 14.342(8), c = 19.481(1), β= 109.057(1) cell parameters. The final R value is 0.044 for 4425 independent reflections. There are various types of ionic and non-covalent interactions including N–H∙∙∙O hydrogen bonding, π-π stacking, and cationic-anionic interactions in the crystal structure of (1). This interactions play important role in the expansion of 3D network of (1).

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The synthesis and X-ray diffraction analysis of a new acidic salt, [4-methyl-phenyl ammonium][(O-phenyl)(hydroxyl)phosphate], [4-CH₃-C₆H₄NH₃][(C₆H₅O)P(O)(O)(OH)], is reported. This compound crystallizes in the monoclinic system, with space group P2₁/c
(a = 9.5147(4) Å, b = 23.2158(10) Å, c = 13.2740(6) Å and b = 111.244(4)°) with four independent components including two cations and two anions in the asymmetric unit. In the crystal, adjacent components are linked together through N–H∙∙∙O and O–H∙∙∙O hydrogen bonds building a ladder arrangement along [100] axis. The Hirshfeld surface analysis and two-dimensional fingerprint plot were used to study intermolecular interactions in the structure. The N–H∙∙∙O and O–H∙∙∙O hydrogen bonds are the characteristic interactions (red areas in the Hirshfeld surfaces). Two sharp spikes in the fingerprint plots of two anions are related to the O…H(O) contacts, while one nearly sharp spike in the fingerprint of two cations is assigned to the O...H(N) contacts.

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Two new polymeric compounds of cadmium acetate using two isomers of pyridine hydrazide ligands have been synthesized and characterized by X-ray diffraction analysis. Structural analysis shows that both compounds were crystallized in monoclinic crystal system with P2₁/c space group. Coordination polymer [Cd(OAc)₂(L1H)]_n (1) which L1H is para pyridine hydrazide, has two dimensional sheets with rectangular net and coordination polymer [Cd₂(OAc)₃(L2H)L2(EtOH)]_n (2) which L2H is meta pyridine hydrazide, has got herringbone structure in 2D dimension.

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1-Phenyl-1,2-ethanediol was synthesized from the hydrolysis of epoxy styrene in water medium. The compound was characterized by FT-IR and NMR spectroscopic methods and structure was characterized by single crystal X-ray diffraction method. The crystallographic information was collected at 293 K. This compound is crystallized in the triclinic  space group with unit cell parameters of a = 6.0274(10) Å, b = 16.204(2) Å, c = 17.345(2) Å; α = 117.584(14)°, β = 99.322(13)°, γ = 90.047 (14)°, V = 1476.1 (4) ų and Z = 8. The asymmetric unit of the crystal structure consists of four molecules of 1-phenyl-1,2-ethanediol which are connected to each other by strong hydrogen bond and C-H∙∙∙π interactions. A supramolecular network is generated by intermolecular O-H∙∙∙O and C-H∙∙∙O hydrogen bond interactions.