One-dimensional Hydrogen-bonded Chains Research Articles

Structural phase transitions and dielectric transitions in a 1,4-diazabicyclo[2.2.2]octane (dabco) based organic crystal

1,4-Diazabicyclo[2.2.2]octane (dabco) based organic crystal [(Hdabco)(H2O)](PF6) (1) was synthesized and characterized. Its structure is featured by wavy-like one-dimensional supramolecular hydrogen bond chains built from the [(Hdabco)(H2O)] units from end to end. Compound 1 undergoes two reversible phase transitions at 226/268 K and 178/181 K, respectively. The disorder-order transition of water molecule in the hydrogen bond chain induces the phase transition at 226 K while the twisting of the [Hdabco]+ cation and displacements of the PF6− anion and H2O molecules trigger the phase transition at 178 K. Dielectric transitions are thus triggered in the crystal.

Studies on Cobalt(II) Complexes with Benzenesulfonate: Synthesis, Crystal Structure, and Spectroscopic and Magnetic Properties

Two novel transition metal benzenesulfonate complexes with a formula [Co(H2O)6][C7H5O3SO3]2⋅2H2O (1) and Na4[Co(H2O)2 Cl4][C7H5O3SO3]2⋅4H2O (2), have been synthesized and characterized by single-crystal X-ray diffraction technique; thermal analysis was done and spectroscopic and magnetic properties were studied. The [Co(H2O)6][C7H5O3SO3]2⋅2H2O (1) complex crystallizes in the triclinic system; however, the (2) complex crystallizes in the monoclinic crystal system with the C2/c space group. Each Co(II) atom in (1) and (2) is octahedrally coordinated. A hydrogen bond links the complex cation and anion, forming one-dimensional hydrogen-bonded supramolecular chains. The complexes exhibit different decomposition characteristics. Magnetic susceptibility measurement shows that complexes have weak anti-ferromagnetic intermolecular interactions between many local spins. The magnitude and nature of these magnetic interactions are discussed in the light of their respective structures, and they are compared with those reported for related systems. Magnetic moments of both compounds at room temperature are characteristic of high-spin complexes Co(II).

Water Structure and Dynamics in Homochiral [Zn(l-L)(X)] Metal–Organic Frameworks

The structural, thermodynamic, and dynamical properties of water adsorbed in two homochiral metal–organic frameworks (MOFs) with general formula [Zn(l-L)(X)], X = Cl and Br, and L = 3-methyl-2-(pyridin-4-ylmethylamino)butanoic acid, are investigated through molecular dynamics simulations. Water molecules establish distinct hydrogen-bonding patterns within the pores of the two MOFs, which directly correlate with the strength of the underlying framework–water interactions. In particular, at low loading, the Zn–Cl groups of [Zn(l-L)(Cl)] effectively provide a templating scaffold for the formation of one-dimensional hydrogen-bonded water chains that propagate along the MOF channels following the helicity of the framework. In contrast, the relatively weaker framework–water interactions in [Zn(l-L)(Br)] lead to less ordered water distributions inside the pores. The simulation results are in agreement with the available experimental data and provide molecular-level insights into specific hydrogen-bonding motifs ...

Energy transport mechanism in the form of proton soliton in a one-dimensional hydrogen-bonded polypeptide chain

The dynamics of protons in a one-dimensional hydrogen-bonded (HB) polypeptide chain (PC) is investigated theoretically. A new Hamiltonian is formulated with the inclusion of higher-order molecular interactions between peptide groups (PGs). The wave function of the excitation state of a single particle is replaced by a new wave function of a two-quanta quasi-coherent state. The dynamics is governed by a higher-order nonlinear Schrödinger equation and the energy transport is performed by the proton soliton. A nonlinear multiple-scale perturbation analysis has been performed and the evolution of soliton parameters such as velocity and amplitude is explored numerically. The proton soliton is thermally stable and very robust against these perturbations. The energy transport by the proton soliton is more appropriate to understand the mechanism of energy transfer in biological processes such as muscle contraction, DNA replication, and neuro-electric pulse transfer on biomembranes.

Solvent-directed Structure Variation from Mononuclear to Bis-methoxo-bridged Binuclear Copper (II) Compound: Crystal Structures and Proton-conduction

In ethanol, the reaction of 2-(methylthio)-4-(pyridin-2-yl)pyrimidine) with Cu(NO3)2 (2-MTPP) yielded a mononuclear Cu(II) coordination compound [(C10H9N3S)2CuNO3]NO3.H2O. In contrast, a discrete bis-methoxo-bridged binuclear Cu(II) coordination compound resulted when ethanol was substituted by methanol. [(C10 H9 N3S)2CuNO3]NO3.H2O and [(C10 H9 N3S)(CH3O) CuNO3]2 have been structurally investigated by single crystal X-ray diffraction. In [(C10H9N3S)2CuNO3]NO3.H2O, uncoordinated nitrate anions and water guest molecules form an interesting one-dimensional hydrogen-bonded chain that is accommodated into an open rhomboidal channel constructed by [Cu(NO3)(2-MTPP)2]+ cations. In [(C10H9N3S)(CH3O)CuNO3]2, binuclear molecules are arrayed in a linear fashion via C–H…O hydrogen bonding interactions. Moreover, [(C10H9N3S)2CuNO3]NO3.H2O has a proton-conductive property with a room-temperature conductivity of 4.96×10−8 S cm−1.

Two-dimensional hydrogen-bonded supramolecular networks in the compounds of benzene-1,2,4,5-tetracarboxylic acid (pyromellitic acid) with 2,2′-biimidazole and 4,4′-dimethyl-2,2′-bipyridine

Two products from the proton-transfer reactions of benzene-1,2,4,5-tetracarboxylic acid (pyromellitic acid, PMA) with 2,2'-biimidazole and 4,4'-dimethyl-2,2'-bipyridine, namely 2,2'-biimidazole-3,3'-diium 2,5-dicarboxybenzene-1,4-dicarboxylate, C6H8N4(2+),C10H4O8(2-), (I), and 4-methyl-2-(4-methylpyridin-2-yl)pyridinium 2,4,5-tricarboxybenzoate monohydrate, C12H13N2(+)·C10H5O8(-)·H2O, (II), have been prepared and their structures determined. Both compounds crystallize in the space group P1. The asymmetric unit of (I) is composed of two independent ion pairs. Both the 2,2'-biimidazole-3,3'-diium dication and the PMA(2-) anion are located on special positions (inversion centres). The protonated 2,2'-biimidazole-3,3'-diium ring H atoms are involved in hydrogen bonding with carboxylate O atoms to form one-dimensional hydrogen-bonded chain structures. Adjacent chains are further linked via carboxyl-carboxyl O-H···O hydrogen bonding, resulting in a two-dimensional supramolecular sheet with the R6(5)(34) motif extending in the (1-21) plane. In (II), classical O-H···O hydrogen-bond-linked anion-anion units are extended into a one-dimensional chain running parallel to the [100] direction, giving an R2(2)(8)R4(4)(30) motif. The chains are connected by water-carboxyl O-H···O hydrogen bonds to form a two-dimensional network parallel to the (011) plane. The 4-methyl-2-(4-methylpyridin-2-yl)pyridinium cations lie between the two-dimensional supramolecular layers linked via N-H···O hydrogen-bonding interactions.

Enhancement of efficiency in organic photovoltaic devices containing self-complementary hydrogen-bonding domains

Self-complementary hydrogen-bonding domains were incorporated as the electron deficient unit in “push–pull”, p-type small molecules for organic photovoltaic active layers. Such compounds were found to enhance the fill factor, compared with similar non-self-organized compounds reported in the literature, leading to higher device efficiencies. Evidence is presented that the ability of these molecules to form one-dimensional hydrogen-bonded chains and subsequently exhibit hierarchical self-assembly into nanostructured domains can be correlated with improved device efficiency.

Calculating Excited States of Molecular Aggregates by the Renormalized Excitonic Method

In this paper, we apply the recently developed ab initio renormalized excitonic method (REM) to the excitation energy calculations of various molecular aggregates, through the extension of REM to the time-dependent density functional theory (TDDFT). Tested molecular aggregate systems include one-dimensional hydrogen-bonded water chains, ring crystals with π-π stacking or van der Waals interactions, two dimensional benzene aggregates and the general aqueous systems with polar and nonpolar solutes. The basis set factor as well as the effect of the exchange-correlation functionals are also investigated. The results indicate that the REM-TDDFT method with suitable basis set and exchange-correlation functionals can give good descriptions of excitation energies and excitation area for lowest electronic excitations in the molecular aggregate systems with economic computational costs. It is shown that the deviations of REM-TDDFT excitation energies from those by standard TDDFT are much less than 0.1 eV and the computational time can be reduced by one order.

Crystal Engineering of Molecular Networks: Tailoring Hydrogen-Bonding Self-Assembly of Tin-Tetrapyridylporphyrins with Multidentate Carboxylic Acids As Axial Ligands

This study reveals the self-assembly patterns of six-coordinate complexes of the tetra(4-pyridyl)- and tetra(3-pyriyl)-tin-porphyrin moieties (SnT4PyP and SnT3PyP, respectively) with multidentate carboxylic acids as axial ligands. Detailed structural characterization of the supramolecular organization in the resulting ordered solids by X-ray diffraction is reported. Crystals of the five new Sn(acid)2-TPyP complexes consist of multiporphyrin polymeric chains and networks that are sustained by extensive hydrogen bonding, involving the functional substituents on the axial ligands as proton donors and the peripheral N-sites of the porphyrin as proton acceptors. The use of different ligands leads to different connectivity features of the supramolecular assemblies that form. Structures with the 5-hydroxy-isophthalic acid and trimesic acid ligands (1 and 2) reveal the formation of one-dimensional hydrogen-bonded chains only, as solvation effects prevent interporphyrin interaction in other directions. Reaction of...

An X-ray crystallographic and density functional theory study of (3Z)-4-(5-ethylsulfonyl-2-hydroxyanilino)pent-3-en-2-one and (3Z)-4-(5-tert-butyl-2-hydroxyanilino)pent-3-en-2-one

The Schiff base enaminones (3Z)-4-(5-ethylsulfonyl-2-hydroxyanilino)pent-3-en-2-one, C13H17NO4S, (I), and (3Z)-4-(5-tert-butyl-2-hydroxyanilino)pent-3-en-2-one, C15H21NO2, (II), were studied by X-ray crystallography and density functional theory (DFT). Although the keto tautomer of these compounds is dominant, the O=C-C=C-N bond lengths are consistent with some electron delocalization and partial enol character. Both (I) and (II) are nonplanar, with the amino-phenol group canted relative to the rest of the molecule; the twist about the N(enamine)-C(aryl) bond leads to dihedral angles of 40.5 (2) and -116.7 (1)° for (I) and (II), respectively. Compound (I) has a bifurcated intramolecular hydrogen bond between the N-H group and the flanking carbonyl and hydroxy O atoms, as well as an intermolecular hydrogen bond, leading to an infinite one-dimensional hydrogen-bonded chain. Compound (II) has one intramolecular hydrogen bond and one intermolecular C=O...H-O hydrogen bond, and consequently also forms a one-dimensional hydrogen-bonded chain. The DFT-calculated structures [in vacuo, B3LYP/6-311G(d,p) level] for the keto tautomers compare favourably with the X-ray crystal structures of (I) and (II), confirming the dominance of the keto tautomer. The simulations indicate that the keto tautomers are 20.55 and 18.86 kJ mol(-1) lower in energy than the enol tautomers for (I) and (II), respectively.

A series of compounds containing various (oxalato)tantalate(v) complex anions – synthesis, properties and the mixed-metal oxide formation via thermal decomposition

Four new ionic, oxalate containing complexes, [Hphen][Ni(phen)3][Ta(C2O4)4]·6.5H2O (1), [Ni(phen)3][Ta(OH)(C2O4)3]·8H2O (2), [Ni(phen)3][Ta(OC2H5)(C2O4)3]·H2O (3) and [Ni(phen)3][Ta(OCH3)(C2O4)3]·H2O (4) (phen = 1,10-phenanthroline) were obtained by using an (oxalato)tantalate(V) solution as a source of complex anions. Crystal structures of all four compounds were solved. The complexes contain the same [Ni(phen)3]2+ cation but different (oxalato)tantalate(V) complex anions. The nickel(II) atom in the cation is coordinated with six nitrogen atoms in a trigonally distorted octahedral environment. The coordination sphere around the tantalum atom is subject to change due to the solvent change. In the complex anion of 1 the tantalum(V) atom is octacoordinated by eight oxygen atoms from the four oxalate groups, whereas in the anions of 2, 3 and 4 the coordination polyhedron around tantalum is a distorted pentagonal bipyramid comprising six oxygen atoms from the three oxalate groups and another oxygen atom from the additional oxygen ligand. Different complex anions in 1–4 give rise to the variability of the structural architectures. Crystallization water molecules and the (oxalato)tantalate(V) anions direct diverse hydrogen bonding patterns: from one-dimensional hydrogen-bonded chains in 3 and 4, to an extended three-dimensional framework in 2. Compound 1 contains two different cations, [Hphen]+ and [Ni(phen)3]2+, that are involved in a two-dimensional stacking arrangement. The compounds were studied also by TG/DTA analysis, and the composition of the oxides, as the final decomposition product, was checked by the powder X-ray diffraction method. The results indicate that the new compounds are prospective and applicable Ni–Ta precursors for the synthesis of nickel tantalate, NiTa2O6.

5-Bromo-2-hy-droxy-benzonitrile.

The title compound, C7H4BrNO, crystallizes with two mol­ecules in the asymmetric unit. The two molecules exhibit nearly linear C—C N nitrile bond angles of 179.1 (4) and 177.1 (4)°. In the crystal, the mol­ecules are linked into a one-dimensional hydrogen-bonded chain by inter­actions between the phenol H atom and the nitrile N atom [N⋯O = 2.805 (4) and 2.810 (4) Å].

Synthesis and properties of catechol-fused tetrathiafulvalene derivatives and their hydrogen-bonded conductive charge-transfer salts

Catechol-fused tetrathiafulvalene (TTF) derivatives have been designed and synthesized as a new type of π-electron donor molecules having two phenolic hydroxyl groups. Cyclic voltammetry measurements and quantum chemical calculations demonstrated the electronic effect of the direct fusion of the catechol unit to the TTF π-skeleton. In the charge-transfer (CT) salts with bromide or chloride anions, a one-dimensional hydrogen-bonded chain was formed by the intermolecular OH⋯X network between the catechol moieties and the halide anions. The slight dissimilarity of the hydrogen-bond distances for the two CT salts gave rise to the significant differences in their overall molecular arrangements and intermolecular interactions as well as the electrical resistivities.

Magnetic Tuning of All-Organic Binary Alloys between Two Stable Radicals

Mixtures of 2-(4,5,6,7-tetrafluorobenzimidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (F4BImNN) and 2-(benzimidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (BImNN) crystallize as solid solutions (alloys) across a wide range of binary compositions. (F4BImNN)(x)(BImNN)((1-x)) with x < 0.8 gives orthorhombic unit cells, while x ≥ 0.9 gives monoclinic unit cells. In all crystalline samples, the dominant intermolecular packing is controlled by one-dimensional (1D) hydrogen-bonded chains that lead to quasi-1D ferromagnetic behavior. Magnetic analysis over 0.4-300 K indicates ordering with strong 1D ferromagnetic exchange along the chains (J/k = 12-22 K). Interchain exchange is estimated to be 33- to 150-fold weaker, based on antiferromagnetic ordered phase formation below Néel temperatures in the 0.4-1.2 K range for the various compositions. The ordering temperatures of the orthorhombic samples increase linearly as (1 - x) increases from 0.25 to 1.00. The variation is attributed to increased interchain distance corresponding to decreased interchain exchange, when more F4BImNN is added into the orthorhombic lattice. The monoclinic samples are not part of the same trend, due to the different interchain arrangement associated with the phase change.

Dichlorido[(1R,2R)-N-(pyridin-2-ylmethyl)cyclohexane-1,2-diamine-κ3N,N′,N′′]mercury(II)

In the title compound, [HgCl2(C12H19N3)], the HgII ion is coordinated by three N atoms of the (1R,2R)-N-(pyridin-2-ylmeth­yl)cyclo­hexane-1,2-diamine ligand and by a Cl atom in the basal plane, and by a second Cl atom in the apical position, within a distorted square-pyramidal geometry. The coordination of the enanti­opure ligand to the metal atom renders the central N atom chiral with an S configuration, so the complex is enanti­omerically pure and corresponds to the S,R,R diastereoisomer. Mol­ecules are linked via weak N—H⋯Cl hydrogen bonds into a one-dimensional hydrogen-bonding supramolecular chain along the crystallographic b axis.

The solvates of sulfamerazine: structural, thermochemical, and desolvation studies

The ability of an antibacterial agent, sulfamerazine (SMZ), to form solvates is investigated. Six solvates, with the solvents 1,4-dioxane (1:1 and 1:0.5), dimethylacetamide, dimethylformamide, cyclopentanone and 3-picoline, were identified and characterized by various analytical techniques, namely, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction. Crystal structure analysis revealed a dimer via a pair of intermolecular N–H⋯N hydrogen bonds between two molecules of SMZ and extended hydrogen bonded networks mediated by the solvent molecules. The conformationally flexible SMZ molecule adopts different conformations in the crystal structures. Thermal analysis established the stability and confirmed molar ratios of the reported solvates. Crystal structures of the sulfonamide drugs were retrieved from the Cambridge Structural Database (CSD) and analyzed to rationalize the factors that favour the solvate formation in sulfonamide drugs. It was found that the CSD statistics under-represent the true prevalence of solvates and polymorphs of sulfonamide drugs, and solvents that contain hydrogen bond acceptor groups have higher likelihood of forming solvates with sulfonamide drugs. Furthermore, a one-dimensional hydrogen bond chain motif was predominantly observed in the crystal structures of solvates/hydrates.

Topology-dominated dynamic wetting of the precursor chain in a hydrophilic interior corner

The topology-dominated dynamic wetting of a droplet in a hydrophilic interior corner was explored using molecular dynamics simulations and molecular kinetic theory. A wetting transition in the interior corner of a single-file water-molecule precursor chain (PC), which eliminated the stress singularity and advanced much faster than the precursor film, was controlled by the interior angle. Owing to the confinement in the interior corner, the potential surface is lower and smoother. The one-dimensional hydrogen-bond chain transferred the disjoining pressure to drive the PC to slip-like ice. As an example, a stable and long metallic monatomic chain was formed using the unique transport properties of the PC for the first time. Our results may help in understanding the topology-dominated dynamic wetting in a hydrophilic interior corner, expand ‘Taylor conjecture’ to nanoscale and develop new applications at nanoscale.

One-Dimensional Hydrogen-Bonded Infinite Chain from Nickel(II) Tetraaza Macrocyclic Complex and 1,2-Cyclopentanedicarboxylate Ligand

The reaction of [Ni(L)]Cl2·2H2O (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo [14,4,01.18,07.12]docosane) with trans-1,2-cyclopentanedicarboxylic acid (H2-cpdc) yields a 1D hydrogen-bonded infinite chain with formula [Ni(L)(H-cpdc−)2] (1). This complex has been characterized by X-ray crystallography, spectroscopy and cyclic voltammetry. The crystal structure of 1 exhibits a distorted octahedral geometry about Ni atom with four nitrogen atoms of the macrocycle and two oxygen atoms of the H-cpdc− ligand at the axial position. Compound 1 crystallizes in the monoclinic system P21/c with a = 8.7429(17), b = 10.488(2), c = 18.929(4) Å, β = 91.82(2), V = 1734.8(6) Å3, Z = 2. Electronic spectrum of 1 reveals a high-spin octahedral environment. Cyclic voltammetry of 1 undergoes two waves of a one-electron transfer corresponding to NiII/NiIII and NiII/NiI processes.

Aromatic single-walled organic nanotubes self-assembled from NH-bridged azacalix[2]triptycene[2]pyridine

A novel triptycene-derived NH-bridged azacalixarene can self-assemble into an aromatic single-walled organic nanotube with large dimensions by four one-dimensional hydrogen bond chains.

Photochemical control of dielectric properties based on intermolecular proton transfer in a hydrogen-bonded diarylethene crystal

The photochromic reaction of a diarylethene derivative having imidazoline rings reversibly modulates the dielectric properties of the crystal, which is based on the intermolecular proton transfer in one-dimensional (1D) hydrogen-bonded chains.