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Anion recognition by neutral hosts that function in aqueous solution is an emerging area of interest in supramolecular chemistry. The design of neutral architectures for anion recognition still remains a challenge. Among neutral anion receptor systems, urea and its derivatives are considered as "privileged groups" in supramolecular anion recognition, since they have two proximate polarized N-H bonds exploitable for anion recognition. Despite promising advancements in urea-based structures, the strong hydrogen bond drives detrimental self-association. Therefore, immobilizing urea fragments onto the rigid structures of a metal-organic framework (MOF) would prevent this self-association and promote hydrogen-bond-accepting substrate recognition. With this aim, we have synthesized two new urea-containing metal-organic frameworks, namely [Zn(bpdc)(L2)]n·nDMF (TMU-67) and [Zn2(bdc)2(L2)2]n·2nDMF (TMU-68) (bpdc = biphenyl-4,4'-dicarboxylate; bdc = terephthalate; L2 = 1,3-bis(pyridin-4-yl)urea), and we have assessed their recognition ability toward different anions in water. The two MOFs show good water stability and anion affinity, with a particular selectivity toward dihydrogen arsenate for TMU-67 and toward fluoride for TMU-68. Crystal structure characterizations reveal 3-fold and 2-fold interpenetrated 3D networks for TMU-67 and TMU-68, respectively, where all single interpenetrated networks are hydrogen bonded to each other in both cases. Despite the absence of self-quenching, the N-H urea bonds are tightly hydrogen bonded to the oxygen atoms of the dicarboxylate ligands and cannot be directly involved in the recognition process. The good performance in anion sensing and selectivity of the two MOFs can be ascribed to the network interpenetration that, shaping the void, creates monodimensional channels, decorated by exposed oxygen atom sites selective for arsenate sensing in TMU-67 and isolated cavities, covered by phenyl groups selective for fluoride recognition in TMU-68.

Many piesce of research have been performed to detect nitroaromatic-compounds (NACs) by metal-organic frameworks (MOFs). Despite extensive studies, there are still significant challenges like selective detection of specific NAC group in presence of other NACs. Here, we have integrated two functionalization strategies through decoration of pore-walls of the MOFs with trifluoromethyl groups and extension in π-conjugated system. Based on this idea, trifluoromethyl TMU-44 (with the formula [Zn2(hfipbb)2(L1)]n. D MF, H2hfipbb = 4,4′-(hexafluoroisopropylidene) bis(benzoic acid), L1 = N,N′-bis-pyridin-4-ylmethylene-benzene-1,4-diamine) and TMU-45 (with formula [Zn2(hfipbb)2(L2)]n. D MF, L2 = N,N′-bis-pyridin-4-ylmethylene-naphthalene-1,5-diamine) frameworks have been synthesized. The aromatic skeleton of TMU-44 is based on phenyl rings while TMU-45 aromatic skeleton is extended by replacement of phenyl with naphthyl core. Measurements reveal that these MOFs are highly sensitive to phenolic NACs especially 2,4,6-trinitrophenol (TNP) with high quenching efficiency of 90% for TMU-44 (KSV = 10,652 M−1, LOD = 6.9 ppm) and 99% for TMU-45 (KSV = 34,741 M−1, LOD = 2.07 ppm). The proposed detection mechanism can be associated with hydrogen bonding between OH group of phenolic NACs and trifluoromethyl groups of TMU-MOFs as well as π(rich)∙∙∙π(deficient) interaction between π-conjugated backbone of TMU-frameworks and π-deficient ring of NACs.

A series of new Ru(II) half-sandwich complexes with the general formula [(arene)Ru(L)Cl2], where L is a monodentate amine ligand and arene is a p-cymene or benzene ring, were synthesized and characterized and their supramolecular structures were analyzed. The crystal packing of these compounds was studied using geometrical analysis, Hirshfeld surface analysis and theoretical calculations. Our study reveals the importance of three common hydrogen bonding motifs as the primary factor controlling the supramolecular architecture of this series of complexes. Furthermore, the role of an amine ligand substituent could be different depending on the type of interactions that occurs between functional groups. Interestingly, homomeric self-complementary intermolecular interactions are formed when the ancillary ligand contains benzyl cyanide or alkyl 4-aminobenzoate. These non-conventional interactions could be promising for the design of organometallic supramolecular arrays.

A new TbIII complex of 5-fluorouracil-1-acetate (5-FUA) and 1,10-phenanthroline(phen), [Tb(phen)(5-FUA)3] n · H2O, has been synthesized, characterized by elemental analysis, IR spectroscopy, XRD powder diffraction, thermal analysis and its structure has been determined by X-ray crystallography. The structural studies show that compound to be a two-dimensional coordination polymer and the Tb atoms to have ten-coordinate geometry, TbN2O8. Self-assembly of this compound in the solid state is likely caused by N–H· · ·O, O – H· · ·O and O–H· · ·F hydrogen bonding.

Two lanthanum(III) complexes of 1,10-phenanthroline (phen) with anionic uracil-1-acetato and 5-fluorouracil-1-acetato ligands, [ La(phen) X 3 ] n , X=Uracil-1-Acetate (UA) and 5-Fluorouracil-1-Acetate (5-FUA), have been synthesized and characterized by elemental analysis and IR spectroscopy and studied by XRD powder diffraction, thermal analysis and X-ray crystallography. The single crystal X-ray analyses show that each lanthanum(III) ion is coordinated by two N atoms from phen, seven carboxylate oxygen atoms and one carbonyl oxygen atom from “UA” and “5-FUA” anions, resulting in a distorted bicapped square antiprism geometry. Packing of these compounds in the solid state via hydrogen bonding is discussed.

A novel europium(III) coordination polymer, [Eu2(bpdc)3(phen)2(H2O)2] n ·nH2O (1) (bpdc = biphenyl-2,2′-dicarboxylate; phen = 1,10-phenanthroline), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction methods. Complex 1 is monoclinic, space group C2/c, with a = 24.3862(6), b = 12.0792(3), c = 22.9120(5) A, α = 90.00, β = 115.160(1), γ = 90.00°, V = 6108.8(3) A3, Z = 4, final R 1 = 0.0605 and wR 2 = 0.1760. Each Eu(III) ion is coordinated by six oxygen atoms from three carboxylate groups of three different bpdc anions, an oxygen atom from one coordinated water molecule and two nitrogen atoms from one phen ligand to complete a deformed monocapped square antiprism. Each pair of bpdc anions acts as a tetradentate ligand to connect two adjacent Eu(III) ions through chelating carboxylate groups, resulting in a centrosymmetric binuclear unit. Each binuclear unit links two adjacent binuclear units through two terminal bpdc anions to produce a one-directional zigza...

Phenomenon of molecular recognition between honokiol and 1,4-diazabicyclo[2.2.2]octane (DABCO) is discovered, and applied to separation of honokiol from extract of magnolia bark. Effects of material ratio on the yield and the purity were investigated. Honokiol (purity up to 97.3% and yield up to 83.9%) is obtained from Magnolia bark extract (honokiol 49.1%, magnolol 31.7%, others unknown 19.2%) on a favorable condition. The title complex, C18H18O2·C6H12N2, is characterized by IR and 1HNMR and its crystal structure is determined by X-ray diffraction method. It crystallizes in monoclinic space group C2/c with a=38.860(3), b=9.205(3), c=12.588(4) A, β=102.730(10)°, V=4392(2) A3, Z=8 and R=0.0500. Hinokiol molecules join to DABCO via O–H...N hydrogen bonds to form infinite chains. There are two symmetry independent DABCO molecules occupying in the crystal special positions of different point symmetries, C2 and Ci. Those located around the inversion center are disoredered as DABCO molecule is devoid of this symmetry element.

In the title complex, C13H11N3O6, it is observed that the very strong NHO [N⋯sO 2.525(2) A] holds the molecules of 3,5-dinitrobenzoic acid and 4-methylpyridine together, and that the hydrogen atom is centered between the hydrogen donor and acceptor in that hydrogen bond. The heterocyclic moiety appears as an intermediate between pyridine and pyridinium, while the benzoic acid between carboxylate and carboxylic group. The title complex is further stabilized by CHO hydrogen bonds and π–π interaction.

In the two related polymeric title compounds, [[La2(sip)2(phen)2(H2O)3].H2O]n [sip is the 5-sulfonatoisophthalate trianion (C8H3O7S3-) and phen is 1,10-phenanthroline (C12H8N2)], (I), and [[La(sip)(H2O)3].H2O]n, (II), the lanthanum(III) ions are nine-coordinate, with similar distorted monocapped square-antiprism coordination geometry. The two crystal structures are very different. In (I), the sip anion acts as a pentadentate ligand, one of the coordinated water molecules lies on a twofold axis and further inversion, n-glide and translation operations generate a two-dimensional framework. In (II), the sip anion functions as a hexadentate ligand and a three-dimensional network with trinuclear 24-membered rings is developed via inversion, n-glide, twofold-screw and translation operations. Both structures also have extensive O-H...O hydrogen-bonded networks and pi-pi interactions.

A unique coordinated molecular capsule compound is synthesized and characterized by X-ray diffraction. The compound crystallizes in cubic space group of Pa-3 with a=14.348(1), b=14.348(1), c=14.348(1) A , V=2953.8(4) A 3 , Z=8. The diazabicyclo[2.2.2]octane-1,4-diium is occluded in the cubic anionic coordinated framework of K+ and (ClO4)− in a dimension of 7.174(1) A, and assumes ordered feature. All of hydrogen atoms take parts in trifurcated hydrogen bonds of N–H⋯O and C–H⋯O type, respectively, the later being reported for the first time. The IR spectrum of the title compound shows significant shift of CH2 vibrational bands, and are correlated with X-ray structural data.

A crystalline salt of prolinium picrate, C11H12N4O9, has been prepared and characterized by X-ray crystallography. The salt crystallizes in orthorhombic space group P212121 with a = 6.325(1)A, b = 9.269(1)A, c = 24.379(4)A, V = 1429.4(5)A3, Z = 4. In the title salt, the picrate and prolinium ion are held by different bifurcated hydrogen bonds of N-H—O type, and stablized by bifurcated hydrogen bonds of CH—O type. There exists a competion between hydrogen bonds and π–π stacking in determining the title crystal. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

An anomalous salt in the 2:3 ratio of the original partners of 2-amino-3-methylpyridine and maleic acid, named tautomerically and structurally as the 2:1 complex of ( E )-2(1 H )-6-methyl-pyridiniminium hydrogen maleate with maleic acid, has been prepared and characterized by X-ray crystallography. The salt crystallizes in the monoclinic space group C 2/ c with a=15.891(2) A , b=5.4040(10) A , c=30.761(4) A , β =94.810(10)°, V=2632.3(7) A 3 , Z =4. The maleic acid partner adopts two forms of configuration, the hydrogen maleate anion and the original maleic acid. The hydrogen maleate anion is tied by O–H⋯O short intramolecular hydrogen bonds with a non-centered hydrogen atom, and bridged by maleic acid with hydrogen bond of OH⋯O to form whole crystal. The hydrogen maleate anion is linked to the individual pyridinium cation by intermolecular hydrogen bond of N(sp 2 )–H⋯O and N(sp 3 )–H⋯O. The heterocycle is fully protonated, which arouses amino–imino tautomerization. The geometrical arrangement in the crystal structure is characterized by the formation of laminar dimers of centrosymmetric pyridiniminium hydrogen maleate that is arranged in a manner of layer upon layer.

A new crystal of 2-amino-3-methylpyridinium ortho-phthalate has been prepared and characterized by X-ray crystallography. The salt crystallizes in the monoclinic space group P21/c with a = 11.015(2) A, b = 11.057(2) A, c = 15.767(2) A, α = 90.00°, β = 96.220(10)°, γ = 90.00°, V = 1909.0(5) A3, Z = 4. In the cell unit, the phthalate anion is linked with two pyridinium cations by NHO hydrogen bond on both sites of annular and exocyclic nitrogen atoms. The two pyridinium cations are arranged in a face-to-face pattern with a dihedral angle of 7.3° and a shortest aspectant distance of 3.4(1) A between them, indicating the existence of π–π interaction. The C(5) atom is an electron donating center. The exocyclic N atom is an electron receiving center, which is consistent with features of imino resonance evidenced by bond lengths and angles. In the cell unit, two entities of pyridinium cation are aligned with each other in a face-to-face manner of electron receiving to donating center.

In the title crystal structure, C19H24N2O2+·2ClO4 −, cations and anions are connected by intermolecular O—H...O and N—H...O hydrogen bonds, forming one-dimensional chains propagating in the the a-axis direction. These chains are, in turn, linked by weak C—H...O hydrogen bonds, forming a three-dimensional network.

In the title complex, C8H8FN3O5·0.5C10H8N2, one [(5-fluoro-2,4-dioxo-1,2,3,4-tetra­hydro­pyrimidin-1-yl)acetamido]acetic acid mol­ecule and one half 4,4′-bipyridine mol­ecule comprise the asymmetric unit. The 4,4′-bipyridine molecule has inversion symmetry. All bond lengths and angles in both molecules show normal values. An extensive three-dimensional network of inter­molecular N—H⋯O and O—H⋯N hydrogen bonds stabilizes the crystal packing.

The asymmetric unit of the title compound, C10H9N2 2+·2C6H4FN2O4 −·2H2O, consists of one half of the (E)-4,4′-ethylenedipyridinium cation, one [(5-fluoro-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-4-yl)acetamido]acetate anion and one water molecule, the complete formula unit being generated by a crystallographic inversion centre at the mid-point of the central C=C bond of the (E)-4,4′-ethylenedipyridinium cation. In the crystal structure, a three-dimensional network is formed via N—H...O and O—H...O hydrogen bonds.

The title salt, bis(methyl 3,4-didehydroibogamin-6-ium-18-carboxylate) (2R,3R)-tartrate trihydrate, 2C21H25N2O2 +·C4H4O6 2−·3H2O, contains two catharanthinium cations, a (2R,3R)-tartrate anion and three water solvent molecules. The cation contains an indole ring system with a planar conformation and a seven-membered nitrogen-containing ring with a distorted chair conformation. A network of O—H...O and N—H...O intermolecular hydrogen bonds stabilizes the crystal packing.

The monomeric title complex, [Cd(C7H5O2)2(C10H8N2)(H2O)]·H2O, contains a seven-coordinate CdII atom and the CdO5N2 polyhedron is irregular. Hydrogen bonds between water mol­ecules and carboxylate groups give rise to a one-dimensional extended architecture.

In the title compound, (C7H10N)2[Cr2O7], the pyridinium cations and dichromate anion are linked by N—H⋯O hydrogen bonds. π–π stacking and C—H⋯O inter­actions play subordinate roles in forming the supramolecular structure.

The title compound, (C15H25N2O)[FeCl4], consists of one matrinium cation {matrine is (7aS,13aR,13bR,13cS)-dodeca­hydro-1H,5H,8H-dipyrido[2,1-f:3′,2′,1′-ij][1,6]-naphthyridin-10-one} and one [FeCl4]− anion. One ring of the matrinium cation has a half-chair conformation, whereas the others have chair conformations. Chiral chains of the title compound are formed by C—H⋯O and N—H⋯O hydrogen bonds.

The mol­ecule of the title compound, C19H11Cl2F3N4O, is a tricyclic amide with an overall U shape. The dihedral angles between the pyrazole and outermost benzene and phenyl rings are 89.4 (1) and 114.5 (1)°, respectively. In the crystal structure, inter­molecular N—H⋯N hydrogen bonds, with an N(amide)⋯N(cyano) separation of 3.220 (7) A, link the mol­ecules into linear chains along the [110] direction.

In the title compound, [Cu(C2Cl3O2)2(C12H8N2)(H2O)], the copper(II) ion is five-coordinated by four basal atoms (two N atoms from a 1,10-phenanthroline mol­ecule and two O atoms from two trichloro­acetate anions) and one axial aqua mol­ecule, in a distorted square-pyramidal coordination geometry. Moreover, two adjacent mononuclear units are associated by intra- and inter­molecular O—H⋯O hydrogen bonds to form a grid dimer. The hydrogen-bonding pattern could be described in graph-set terminology as R11(6)R12(8).

The title compound, [Zn(H2O)6][ZnCl3(C8H10N4O2)]2·2H2O, consists of two disordered water mol­ecules, one hexa­hydrated ZnII cation and two [ZnIICl3(caffeine)]− anions, which are arranged around an inversion center. The coordination around the hexa­hydrated ZnII cation is octa­hedral. This cation is linked with [ZnIICl3(caffeine)]− anions and water mol­ecules via O—H⋯O hydrogen bonds. Moreover, O—H⋯O and O—H⋯Cl hydrogen bonds are co-operative in building up two-dimensional bilayers in which hexa­hydrated ZnII cations are sandwiched between two layers of [ZnIICl3(caffeine)]− anions, which are anti-parallel to each other.

In the title compound, 2C18H18O2·C6H12N2, 5,5′-diallyl­biphenyl-2,2′-diol and 1,4-diaza­bicyclo­[2.2.2]octane mol­ecules are linked by O—H⋯O and O—H⋯N hydrogen bonds.

The title compound, (C4H12N2)2[Mn2Cl6(H2O)4]Cl2, consists of two piperazinium cations, two chloride anions and a dimanganese complex anion, which lies on a center of symmetry. Each MnII atom is located in a distorted octa­hedral environment. The cations and the anions are held together by O—H⋯Cl and N—H⋯Cl hydrogen bonds. The structure features the formation of inorganic and organic ionic layers, which interpenetrate each other and which are linked by hydrogen bonds.

In the crystal structure of the title compound, C13H14N3+·C2HO4−, each cation is linked to four adjacent anions by inter­molecular N—H⋯O hydrogen bonds [N⋯O = 2.870 (4)–2.895 (4) A], and each anion is also linked to two adjacent anions by O—H⋯O hydrogen bonds [O⋯O = 2.526 (3) A] to form a two-dimensional grid network parallel to (100).

In the title compound, [NiCl2(C7H9N)4], where C7H9N is 3,5-lutidine, the NiII atom is coordinated by two Cl atoms and four N atoms from 3,5-lutidine groups. The geometry around the NiII atom, which is located at a special position of symmetry 422, is octahedral. Mol­ecules of the title compound are connected by C—H⋯Cl inter­molecular hydrogen bonds and C—H⋯π inter­actions to form a three-dimensional structure.

The title compound, C18H16N2OS, crystallizes in a triclinic unit cell with two independent mol­ecules in the asymmetric unit. Intermolecular N—H⋯S, C—H⋯O and C—H⋯S hydrogen bonds link the mol­ecules into ribbons, which form stacks with short intra- and intermolecular S⋯C [3.385 (5) A] and C⋯O′ [3.162 (5) A] contacts.

The title compound, C10H9N2+·C8H4NO6−·C8H5NO6·2H2O, consists of singly protonated 2,2′-bipyridinium cations, 5-nitroisophthalate anions, 5-nitroisophthalic acid and water mol­ecules of crystallization, linked by N—H⋯O and O—H⋯O hydrogen bonds. The moieties are linked by multiple hydrogen bonds into an undulating sheet structure.

The title compound, (C6H9N2)2[Zn(II)Cl4], consists of two 2-amino-6-methylpyridinium (AMP) cations and one [ZnCl4]2- anion, which are held together by N-H...Cl hydrogen bonds. Bond lengths within the AMP cation indicate that the imine tautomer makes a significant contribution to the structure. The molecules are associated by two different pi-pi interactions between identical antiparallel AMP cations, with face-to-face distances of 3.627 (4) and 3.342 (3) A, to form a one-dimensional chain.

In the title compound, C12H20NO+·Br−·1.5H2O, two crystallographically independent quaternary ammonium cations are associated by three very short C—H⋯π interactions with distances between the H atoms and the centroids of the benzene rings of 2.787 (8), 2.878 (7) and 2.932 (8) A. A one-dimensional hydrogen-bonded spiral is formed along the b axis by O—H⋯Br hydrogen bonds. Neighboring spirals are interrelated by translation and held together mainly by hydrogen bonds and O—H⋯O interactions. C—H⋯O and C—H⋯Br hydrogen bonds and C—H⋯π interactions play an important role in stabilizing the structure.

The salt of bis(2,3,5-trimethylpyridine N-oxide) 2,4,6-trinitrophenolate, C22H25N5O9, crystallizes in monoclinic space group C2/c with a=12.411(2)A, b=15.326(3)A, c=13.559(3)A, β=113.13(1)°, V=2371.8(8)A3, Z=4, Dc=1.410 mg/m3, F(000)=1056. The molecule of 2,3,5-trimethylpyridine N-oxide is protonated. Two pyridine N-oxide molecules are linked by extremely strong OHO hydrogen bonding (2.378(4)A) to form a cation complex. CHO hydrogen bonding and π–π interactions also play important role in stablizing the structure of the salt.

In the title adduct, C 6 H 12 N 2 .C 7 H 5 O 2 , the orcin and 1,4-diazabicyclo[2.2.2]octane moieties are held together by O-H...N hydrogen bonds. One-dimensional chiral hydrogen-bonded chains are formed along the b axis. Neighbouring chains are held together principally by van der Waals interactions and are interrelated by translation, resulting in a chiral layer.

In the title salt, C12H24N+·C6H5O4S−·H2O, the di­cyclo­hexyl­aminium cation is linked to the 4-hydroxy­sulfonate anion and water mol­ecules via N—H⋯O and O—H⋯O hydrogen bonds. The water mol­ecule acts as both a hydrogen donor and acceptor in establishing a three-dimensional hydrogen-bonded network.

In the title compound, [Co(C10H4O8)(C12H8N2)(H2O)3]·H2O, the Co atom has an octahedral coordination geometry, involving three aqua O atoms, one carboxyl­ate O atom and two N atoms from a 1,10-phenathroline (phen) mol­ecule. O—H⋯O hydrogen bonds involving di­hydrogen-1,2,4,5-benzenetetra­carboxyl­ate (H2TCB) anions, aqua ligands and uncoordinated water mol­ecules, along with π–π interactions between the phen and aromatic rings of symmetry-related H2TCB anions, link the mononuclear units into a three-dimensional network structure.

In the title compound, [Co(C4H4O5)(C3H4N2)3], the cobalt(II) cation is located at the center of a distorted octahedron, being coordinated by three N atoms from three imidazole ligands and three O atoms from a malate ion. In the crystal structure, enantiomers are linked by pairs of bifurcated N—H⋯O hydrogen bonds to form racemic dimers.

In the title salt, C4H12N22+·2C4H3O4−, the diprotonated piperazine cation links to two hydrogen maleate anions through N—H⋯O hydrogen bonds. An H atom is approximately centered in an extremely short intramolecular hydrogen bond of the O⋯H⋯O type in each of the hydrogen maleate anions.

The 2-amino­pyrimidin-1-ium tri­chloro­acetate ion-pairs in the title compound, C4H6N3+·C2Cl3O2−, are held together by two N—H⋯O hydrogen bonds [Namino⋯O = 2.733 (5); Npyrimidinium⋯O = 2.783 (6) A], and adjacent ion-pairs are linked into a linear helical chain by a third and substantially weaker N—H⋯O hydrogen bond [N⋯O = 3.026 (3) A]. The calculated structure of the ion-pair geometry, optimized at the PM3 level, shows good agreement with the experimental results.

In the title complex, {[Cu(C8H8NO3S)2(H2O)] x 2 H2O}n, the Cu(II) cation has a distorted square-pyramidal coordination environment consisting of five O atoms, one from a water molecule, one from an N-O group and the other three from the carboxylate groups of two 3-(2-pyridylsulfanyl)propionate N-oxide anions. The aqua[3-(2-pyridylsulfanyl)propionato N-oxide]copper(II) moieties are bridged by 3-(2-pyridylsulfanyl)propionate N-oxide anions to form an infinite three-dimensional coordination polymer with a zigzag chain structure. The crystal structure is stabilized by hydrogen bonds.

In the polymeric title compound, [CuCl2(C6H6N4)]n, each CuII ion is five-coordinated by four basal atoms (two N atoms from a 2,2'-biimidazole molecule and two Cl- anions) and one axial Cl- anion, in a distorted square-pyramidal coordination geometry. Cl- anions bridge the {Cu(C6H6N4)Cl} units into one-dimensional linear chains, which are reinforced by pi-pi interactions. Adjacent linear chains are linked by N-H...Cl hydrogen bonds, resulting in a grid layer. The hydrogen-bonding pattern can be described in graph-set notation as C(2)2(9)R(2)2(9)R(2)2(14). This study extends our knowledge of the multifunctional properties of the 2,2'-biimidazole ligand and of the coordination stereochemistry of copper(II).

The title complex, C 8 H 6 O 4 .2C 6 H 7 N, consists of two crystallographically independent 1:2 clusters of benzene-1,3-dicarboxylic acid and 4-methylpyridine. Each cluster, the components of which are linked by O-H...N hydrogen bonds, is almost planar by alignment of C-H...O hydrogen bonds. Herring-bone ribbons of clusters are formed by other C-H...O hydrogen bonds, and these ribbons are further packed to form a laminar structure by π-π interactions.

The title compound, (C6H9N2)[ZnCl3(C6H8N2)], consists of one 2-amino-5-methylpyridinium cation and one (2-amino-5-methylpyridine)trichlorozincate(II) anion, which are held together by N-H...Cl hydrogen bonds and pi-pi interactions. The cation and the pyridine ligand show similar geometric features, except for the N-C bond lengths. Molecules of the title compound are connected by N-H...Cl hydrogen bonds to form chiral chains; these chains are associated further by C-H...Cl hydrogen bonds to form layers, which are in turn linked by pi-pi interactions.

In the centrosymmetric title polymer, catena-poly[[bis[aqua(1,10-phenanthroline-kappa2N,N')lead(II)]-di-mu3-5-carboxy-3-sulfonatobenzoato-1:2:1'kappa4O3:O1,O1':O1;2':1:2kappa4O1:O1,O1':O3] dihydrate], {[Pb(C8H4O7S)(C12H8N2)(H2O)].H2O}n, each seven-coordinate lead(II) ion is bound by five O atoms from one water molecule and three 5-sulfoisophthalate (sip) anions, and by two N atoms from a 1,10-phenanthroline (phen) ligand. The sip sulfonate group is monodentate. One O atom of the sip carboxylate group is chelated to one Pb2+ cation, with the other also bridging an adjacent Pb2+ cation. The carboxyl group is uncoordinated. This unusual coordination results in a chain structure along the b axis, which is linked by strong intermolecular hydrogen bonds into a three-dimensional network.

The title compound, (C(6)H(14)N(2))[Cr(2)O(7)], consists of a diazabicyclo[2.2.2]octane-1,4-diium cation and a discrete dichromate anion, which are linked in the crystal by N-H...O hydrogen bonds. The cation is ordered and distorted, owing to the confinement and twist of the hydrogen bonds involved. Two CrO(4) tetrahedra are joined through a shared O atom to form the dichromate anion. Chiral supramolecular chains of the title compound are built up via N-H...O hydrogen bonds, and C-H...O interactions play subordinate roles in forming the structure.

In the title compound, poly[[aqua(1,10-phenanthroline)cobalt(II)]-mu4-dihydrogen benzene-1,2,4,5-tetracarboxylato], [Co(C10H4O8)(C12H8N2)(H2O)]n, each cobalt(II) cation has an octahedral geometry completed by one aqua O atom, three carboxy O atoms belonging to three H2TCB2- anions (H2TCB2- is dihydrogen benzene-1,2,4,5-tetracarboxylate) and two N atoms from a 1,10-phenanthroline molecule. In the asymmetric unit, there are two half H2TCB2- anions lying about independent inversion centres. The bridging H2TCB2- anions have two coordination modes, viz. mu2-H2TCB2- and mu4-H2TCB2-, resulting in a two-dimensional coordination polymer. Furthermore, a three-dimensional network is formed by O(carboxy)...O(carboxy) hydrogen-bond interactions, with H...A distances in the range 1.69-1.82 A, and O(carboxy)...O(water) interactions, with H...A distances in the range 1.91-1.94 A.

In the title complex, pyromellitic acid-dimethyl sulfoxide (1/2), C(10)H(6)O(8).2C(2)H(6)OS, molecules of pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid) and dimethyl sulfoxide, the latter being well ordered, are linked to each other by O-H.O hydrogen bonds. The formula unit displays crystallographic inversion symmetry. The packing consists of ribbons of hydrogen-bonded rings that can be described by graph set C(2)(1)(10)R(4)(2)(18).

In the title crystal structure, C19H36N3 +·Cl−, the central C atom of the N,N′,N′′-tricyclohexylguanidinium ion and the chloride ion both lie on positions of site symmetry 3. Weak N—H...Cl hydrogen bonds [N...Cl = 3.539 (3) Å] link anions and cations, forming a three-dimensional network.

The crystal structure of [GBH](ClO4) (GB = 2-guanidinobenzimidazole) is triclinic, space group P1 with a = 7.3100(8), b = 7.5630(8), c = 10.9496(12)A, α = 108.742(2), β = 91.402(2), γ = 104.590(2)° and Z = 2. The crystal structure was solved by direct methods and refined by full-matrix least squares to final values of R1 = 0.0433 and wR2 = 0.1275 with 1778 reflections (I > 2σ(I)). The [GBH](ClO4) is involved in hydrogen bonding, [GBH]+ acting as a donor with an O and N atoms as acceptor.

The mol­ecule of the title compound, C12H4Cl2F6N4S, exhibits disorder of both trifluoro­methyl groups. Crystal packing is realised by N—H⋯N hydrogen bonds.

In the title compound, [CuCl2(C5H4ClN)2(H2O)], the CuII atom is coordinated by one water mol­ecule, two Cl− ions and two 2-chloro­pyridine mol­ecules. The structure is built up via O—H⋯Cl hydrogen bonds and stablized by π–π stacking and Cl⋯Cl inter­actions.