Cl Hydrogen Bonds Research Articles

Double Pseudopolymeric [Au{S2CN(CH2)5}2]2[Ag2Cl4]·CH2Cl2 Complex: Preparation, Principles of Supramolecular Self-Assembly, Thermal Behavior, and Biological Activity against Mycolicibacterium smegmatis Strain

The double Au(III)–Ag(I) complex crystallizing as the solvated form of [Au{S2CN(CH2)5}2]2[Ag2Cl4]· CH2Cl2 (I) was obtained by the reaction of silver(I) N,N-pentamethylenedithiocarbamate with a solution of Na[AuCl4]/5.15 M NaCl. According to X-ray diffraction data (CIF file CCDC no. 2062810), the structural units of the compound are nonequivalent [Au{S2CN(CH2)5}2]+ cations (noncentrosymmetric A and centrosymmetric B and C in a ratio of 2 : 1 : 1), cyclic tetrachlorodiargentate(I) anions, [Ag2Cl4]2–, and solvating CH2Cl2 molecule. The latter is retained in the structure due to two nonequivalent C–H···Cl hydrogen bonds formed with the cyclic [Ag2Cl4]2– anion involving its terminal Cl(1) and bridging Cl(2) chlorine atoms. The supramolecular self-organization of I is based on a system of multiple Ag···S and Cl···S secondary interactions that сombine the ionic structural units of the complex into an intricate two-dimensional pseudopolymer layer. A study of the thermal behavior of I by simultaneous thermal analysis established the conditions for quantitative reduction of bound gold(III) and silver(I). The studied Au(III)–Ag(I) compound exhibits a high level of biological activity against the nonpathogenic M. smegmatis strain.

Crystal structure of besifloxacin hydrochloride, C19H22ClFN3O3Cl

The crystal structure of besifloxacin hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Besifloxacin hydrochloride crystallizes in space group P1 (#1) with a = 5.36596(8), b = 10.3234(4), c = 17.9673(14) Å, α = 98.122(5), β = 92.9395(9), γ = 96.1135(3)°, V = 977.483(13) Å3, and Z = 2. The crystal structure is approximately centrosymmetric. Strong N–H⋯Cl hydrogen bonds form a corrugated ladder-like chain along the a-axis. The carboxylic acid group in each independent cation acts as the donor in a strong intramolecular O–H⋯O hydrogen bond to an adjacent carbonyl group. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

Redetermination of the crystal structure of di-μ2-hydroxido-bis-[di-tert-butyl-chlorido-tin(IV)] at 100 K.

The structure of the dimeric title compound, [Sn2(C4H9)4Cl2(OH)2], was redetermined at 100 K by use of an area detector to provide new data to improve the structural parameters for detailed analysis. Noteworthy is the folding of the central, non-symmetric, four-membered [SnO]2 ring [dihedral angle about the O⋯O axis = 1.09 (3)°], as well as the elongation of the Sn-Cl bonds [mean value = 2.5096 (4) Å], as a result of inter-molecular O-H⋯Cl hydrogen bonds; the latter lead to a chain-like arrangement of dimeric mol-ecules along [101].

Self-Assembly of a Purely Organic Bowl in Water via Acylhydrazone Formation.

A bowl-shaped molecule can be self-assembled by condensing a triscationic hexaaldehyde compound and three equiv. of a dihydrazide linkers in pure water. The molecular bowl is thus composed of a triscationic π-electron deficient platform, as well as a hexagonal rim that contains six acylhydrazone functions. When the counteranions are chloride, the solid-state structure reveals that this molecular bowl undergoes dimerization via N-H···Cl hydrogen bonds, forming a cage-like dimer with a huge inner cavity. This molecular bowl can employ its cavity to accommodate a hydrophobic guest, namely 1-adamantanecarboxylic acid in aqueous media.

Thermal decomposition kinetics of deep eutectic solvent (DES) based on choline chloride and magnesium chloride hexahydrate: New details on the reaction mechanism and enthalpy–entropy compensation (EEC)

In recent years, deep eutectic solvents (DESs) have attracted considerable attention, and they have been applied in many fields, such as dissolution and separation, electrochemistry, materials preparation, reaction, and catalysis. In this paper, a detailed thermal decomposition mechanism of DES-type II (consisting choline chloride (ChCl) and magnesium chloride hexahydrate (MgCl2·6H2O) in a molar ratio 2:1 (MgCl2·6H2O-[Ch]Cl)) was explained, using thermal analysis techniques. Physicochemical clarification of overall thermal decomposition mechanism and the influence of enthalpy–entropy compensation (EEC) on reactions mechanism emerging are presented for the first time, in favor of this DES type. In the kinetic analysis of the decomposition process, two approaches were used: model-free (inverse) and model-based (direct) methods. It was found that thermodynamic principles in the form of EEC are the source of kinetic compensation effect (KCE) during MgCl2·6H2O-[Ch]Cl thermal decomposition, as a consequence of the effects of molecular interactions. Key phenomenon in the complex multiple step process represents a parallel dehydration steps of MgCl2·6H2O in DES, leading to formation of intermediates, such as [MgCl1(H2O)5]1+ and [MgCl2(H2O)4]. It was established that formation of final products (Mg(OH)2 and MgOHCl) requires a higher expenditure of energy to overcome a high potential barrier, where reaction system compensates this energy via hydrogen bonding disruption. This was confirmed by the identification of a specific ‘oscillator’, flagged as HOH···Cl hydrogen bond donating system of the energy (“heat bath”). All kinetic parameters and mechanisms of individual reaction steps were confirmed by numerical optimization of the process and modulated dynamic predictions.

Structural study, spectroscopic characterization, DFT calculations and electrical properties of manganese (II) organic-inorganic hybrid material (C8H14N2)2[MnCl4(H2O)2]Cl2

The new organic-inorganic compound, (C8H14N2)2[MnCl4(H2O)2]Cl2 denoted (1), crystallizes at room temperature in the monoclinic system, P21/c space group. The structure exhibits an alternate organic-inorganic layered stacking along a-axis. The inorganic layers formed by [MnCl4(H2O)2]2− anion and two uncoordinated chlorine anions. The organic layers are made of protonated m-Xylylenediamine (C8H14N2)2+. Crystal cohesion is achieved through NH…Cl and OH…Cl hydrogen bonds building up a three-dimensional network. The functional groups present in the crystal were studied by FTIR. The optical proprieties were investigated by UV-visible spectroscopy study and the electronic properties HOMO and LUMO energies were calculated by TD-DFT. Thermal behavior (DSC, DTA/TGA) was also performed, while the composition of the phase was verified by semi-quantitative analysis (EDX). Hirshfeld surface (3D-HS) analysis and the two-dimensional fingerprint plots (2D-FP) affirms that the structure is dominated by H…Cl/Cl…H and H…H contacts. Electrical analysis of our compound has been investigated using complex impedance spectroscopy (CIS) in frequency and temperature range 3 uHz-20 MHz and 393–443 K, respectively. Impedance spectroscopy studies show that electrical-conductivity is 1.80 10−6 S cm−1 at 443 K and the activation energy is 2.15 eV.

Synthesis, Crystal Structure, Hirshfeld Surface and Molecular Docking Analysis of bis(N,N-diethylenediamine)cadmium(II)] dichloride

A new Cd(II) complex, bis(N,N-diethylenediamine)cadmium(II)] dichloride, C12H32CdCl2N4, was synthesized by the reaction between cadmium(II) chloride hexahydrate, sodium hydroxide, and N,N-diethylenediamine in aqueous methanol. The crystal structure was characterized by single-crystal X-ray diffraction analysis technique. The crystal structure is monoclinic, space group P21/c with parameters a=6.8959(3) Å, b=16.0795(10) Å, c=16.4406(8) Å, α=90°, β=100.23(4)°, γ=90°, V=1794(16) Å3, Z=4. The X-ray structure analysis reveals that the Cd(II) cation coordinated by four N atoms of the N,N-diethylenediamine units and two Cl atoms, giving it a octahedral geometry. In the crystal, the molecules are linked by N−H···Cl hydrogen bond, forming a three-dimensional supramolecular architecture. A Hirshfeld surface analysis was performed to record various intermolecular interactions, indicating the stabilization of the Cd(II) complex structure by the intermolecular weak N−H···Cl hydrogen bonds. The major interactions are H···H (80.2%) and Cl···H (19.8%) interactions for the title complex.

Investigation of the structure, phase transitions, molecular dynamics, and ferroelasticity of organic-inorganic hybrid NH(CH3)3CdCl3 crystals.

Understanding the physical and chemical properties of the organic-inorganic hybrid NH(CH3)3CdCl3 is essential for its application. Considering its importance, a single crystal of NH(CH3)3CdCl3 was grown with an orthorhombic structure at 300 K. The phase transition temperatures were determined to be 345 (TC3), 376 (TC2), and 452 K (TC1) (phases IV, III, II, and I, respectively, starting from a low temperature). The partial decomposition temperature was 522 K (Td). Furthermore, the NMR chemical shifts of the 1H, 13C, and 113Cd atoms of the cation and anion varied with increasing temperature. Consequently, a significant change in the coordination geometry of Cl around Cd in CdCl6 and a change in the coordination geometry of H in NH was associated with changes in the N-H⋯Cl hydrogen bond near the phase transition temperature. The 13C activation energy Ea obtained from the spin-lattice relaxation time was smaller than that of 1H Ea, suggesting that energy transfer around 13C is easier. Additionally, a comparison of the twin domain walls measured via optical polarizing microscopy and Sapriel's theory indicated that the crystal structure in phase III was more likely to be orthorhombic than hexagonal.

Experimental and Theoretical Characterization of 3-(3,5-Dimethylbenzyl)-1-methyl-3,4,5,6-tetrahydropyrimidinium trichlorido(η6-p-cymene)ruthenate(II)

In this study, the title compound was synthesized, and its structure was illuminated by X-ray diffraction, 1H and 13C NMR spectroscopy methods. X-ray study shows that the crystal structure is stabilized by intermolecular C─H···Cl hydrogen bonds. Quantum mechanical approach was carried out to study the molecular structure, NMR spectra and stability of the compound by using Density Functional Theory (DFT) with HSEH1PBE functional and LanL2DZ basis set. Hirshfeld surface analysis was used as theoretical approach to assess driving force for crystal structure formation via the intermolecular interactions in the crystal lattice. In addition, chemical reactivity and kinetic stability of the molecule based on frontier molecular orbital analysis were investigated.

Crystal growth, phase transition, and nuclear magnetic resonance of organic-inorganic hybrid perovskite NH2(CH3)2CdCl3.

Understanding the physicochemical properties of organic-inorganic hybrid materials is essential to promote their applications. In this study, a single crystal of NH2(CH3)2CdCl3 was grown, and it exhibited a monoclinic structure. Its phase transition temperatures were 460 and 470 K, and it showed sufficient thermal stability. The changes in the NMR chemical shifts of each atom in the crystal with increasing temperature were determined; the chemical shift of 1H of NH2 in the NH2(CH3)2 cation changed with temperature, which was correlated to the changes in the chemical shift of 14N in NH2. The change in 113Cd chemical shifts indicate the change of six Cl atoms around Cd in CdCl6. Therefore, the change in the coordination geometry of CdCl6 is attributed to the change in the N-H⋯Cl hydrogen bond between the NH2(CH3)2 cation and CdCl6 anion. In addition, the 13C activation energies Ea obtained from the spin-lattice relaxation time T1ρ values are smaller than those of the 1H Ea values, suggesting that is free compared to 1H in the cation. We believe that this study furthers our fundamental understanding of organic-inorganic hybrid materials to promote their practical solar cell applications.

Processing on crystal growth, structure, thermal property, and nuclear magnetic resonance of organic-inorganic hybrid perovskite type [NH3(CH2)6NH3]ZnCl4 crystal.

Organic-inorganic hybrid compounds have recently gained significant attention in recent years due to their diverse applications. Herein, [NH3(CH2)6NH3]ZnCl4 crystals were grown, and their triclinic structure, phase transition temperature (TC = 408 K), and high thermal stability (Td = 584 K) was determined using X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetry measurements. By analyzing the chemical in response to temperature changes, we observed that the coordination geometry around 1H and 13C were highly symmetric below TC, whereas their symmetry was lowered above TC. The change of N-H⋯Cl hydrogen bond from XRD results and the change of 14N NMR chemical shifts was due to the changes to the coordination geometry of Cl- around Zn2+ in the ZnCl4 anion. The activation energy of 1H was three times greater than that of 13C, and this result indicates that the energy transfer of 13C was easier than those of 1H. We compared the results for [NH3(CH2)nNH3]ZnCl4 (n = 6) studied here with those for n = 2, 3, 4, and 5 obtained from previous studies. The characteristics of the length of CH2 in the methylene chain are expected to be used for potential applications in the near future.

(Carbazol-9-ido-κN)di-chlorido-(η5:η1-2,3,4,5-tetra-methyl-penta-fulvene)tantalum(V).

The reaction of (η5:η1-2,3,4,5-tetra-methyl-penta-fulvene)tantalum(V) dicarbazolide chloride (1) with etheric HCl results in the formation of the title compound (2), [Ta(C10H14)(C12H8N)Cl2]. The TaV atom has a distorted tetra-hedral coordination environment in a three-legged piano-stool fashion. The conformation of the penta-fulvene exocyclic C atom to the three other ligands is staggered and not eclipsed, as found in the crystal structure of 1. Inter-molecular inter-actions include π-π stacking, H⋯π inter-actions and weak C-H⋯Cl hydrogen bonds.

Theoretical Studies on OH−+NH2Cl Reaction: Nucleophilic Substitution at Neutral Nitrogen

The SN2 and proton transfer (PT) pathways for [Formula: see text]Cl reaction are represented by employing various electronic structure computations. Both back-side SN2 and PT channels are exothermic and stationary points of PESs are below the reactant asymptote. Overall, the PES is similar to the C-centered SN2 reactions. Conversely, ion-dipole complex was not found for [Formula: see text]Cl system. The N–HOH/NH–Cl hydrogen bond characterizes on either side of the reaction barrier of nitrogen complexes. Moreover, a halogen-bonded complex (HO−–ClNH2) and two types of H-bond complexes (HONH2–Cl− and Cl−–HONH2) were described, predicting an important role in dynamics. The PT pathway may be the major channel in the title system, which is contradictory to [Formula: see text]Cl and [Formula: see text]Cl reactions. Here, MP2, B3LYP and CAM-B3LYP methods show overall excellent consistency with CCSD(T)/CBS energies and are recommended to carry out dynamics simulations.

Synthesis, Structural Characterization, and Guest Exchange Properties of Hydrogen-Bonded Organic Frameworks Based on Bis(benzimidazole)ZnCl2 Complexes.

Hydrogen-bonded organic frameworks (HOFs) based on coordination compounds constitute a developing class of interesting porous materials. Herein, we report on the synthesis, crystal structures, and guest exchange properties of four HOFs based on zinc dichlorido complexes that bear a bis(benzimidazolyl)methane ligand (bis(benzimidazole)ZnCl2). The porous structures of these bis(benzimidazole)ZnCl2-based HOFs are characterized predominantly by intermolecular N-H···Cl hydrogen bonds in conjunction with π-π interactions. One of these HOFs was found to exchange guest molecules via single-crystal-to-single-crystal transformations with or without structural change. A single-crystal X-ray diffraction study revealed that the guest exchange accompanied by a structural change is induced by the cleavage of the N-H···Cl hydrogen bonds between the bis(benzimidazole)ZnCl2 complexes, followed by the formation of alternate hydrogen bonds with guest molecules. This result suggests that the use of weaker N-H···Cl hydrogen bonds than those typically used for the construction of HOFs (e.g., carboxylic acid dimers, N-heterocycles, and charge-assisted moieties) may represent a convenient strategy to synthesize flexible HOFs.

Crystal structure of poly[tetrakis(4-methylanilinium) [octa-μ-chlorido-dichloridotricadmium(II)]]: a two-dimensional organic–inorganic hybrid perovskite

The title polymeric compound, (C7H10N)4[Cd3Cl10], involves a centrosymmetric [Cd3Cl10]4− tetra-anion, which is made up of three face-sharing CdCl6 octahedra, linked by four corner Cl atoms, forming layers propagating in the ab plane. The p-methylanilinium cations, situated between the layers, form N—H...Cl hydrogen bonds to the layers, which stack up the c-axis direction. There are no π–π or C—H...π interactions involving the aromatic rings, which are inclined to each other by 42.3 (1) ° in the asymmetric unit.

Triazole-Bridged Zinc Dinuclear Complexes: Mechanochemical Synthesis, Crystal Structure, and Biological Activity.

Two zinc (Zn) complexes, [Zn2(DAT)2Cl4] (I) and [Zn2(DAT)2(NO3)4] (II), were prepared by grinding 3,5-diamino-1,2,4-triazole (C2H5N5, DAT) with Zn precursors such as ZnCl2 and Zn(NO3)2, respectively. This solid-state reaction gives the corresponding Zn complex as the sole product in over 99% yield. This mechanochemical method promotes the selective formation of Zn complexes different from those obtained using the conventional solution-based route. The crystal structures of the two complexes were analyzed by single-crystal X-ray diffraction. Complex (I) crystallizes in the monoclinic space group P21/c, whereas complex (II) crystallizes in the triclinic space group P 1̅. Each complex is characterized by the presence of a characteristic DAT-bridged dimer with one DAT ligand per Zn atom, and the DAT ligand provides a bridge between the two Zn metals. All Zn centers of (I) and (II) adopted a slightly distorted tetrahedral geometry. Both complexes contain a hexanuclear Zn2N4 ring, but their ring structures are different. Complex (I) possesses a boat geometry, while complex (II) has a nearly planar structure. The Zn-bound chlorides of complex (I) form intermolecular N-H···Cl hydrogen bonds that link neighboring molecules. In complex (II), the O atoms in the nitrate groups are hydrogen-bonded to the DAT ligand via O···H-N linkages. Both complexes exhibit blue emissions in the solid state at ambient temperature. They were evaluated as anticancer agents in HeLa, NCCIT, and MCF-7 cancer cell lines, exhibiting promising anticancer activities.

1-Hy-droxy-4-methyl-pyridinium chloride.

The title salt, C6H8NO+·Cl-, contains two cations and two anions in the asymmetric unit. The components are linked by O-H⋯Cl and C-H⋯Cl hydrogen bonds, leading to tetra- (square-planar) or penta-coordinated (square-pyramidal) chloride ions. The title salt is isostructural with its bromide analogue.

Synthesis, structural and exploration of non-covalent interactions of the palladium complex with the crystalline water molecule: A comprehensive quantum chemical approach

A Schiff base ligand, N'-((2-hydroxynaphthalen-1-yl)methylene)-3-phenylpropanehydrazide (L) and its palladium(II) complex [Pd(L)Cl] were synthesized and characterized by FT-IR, SEM, EDAX, and UV–visible and single crystal X-ray diffraction analysis.The crystal structure shows distorted square-planar, where the palladium(II) metal atom is bonded to two oxygen atoms in the equatorial position whereas a nitrogen and chlorine atom along the axial position in a tetradentate monoanionic [O1, O2, N1, Cl1] fashion resulting in the formation of five and six membered chelate rings. The crystal structure is supported by intramolecular NH…O and OH…Cl hydrogen bonds, CH…Cl, NH…O, CH…π and π…π intermolecular secondary interactions resulting in the supramolecular architectures. The 3D description of the intermolecular interactions are quantified using the Hirshfeld surface analysis. Density functional theory (DFT) calculations were performed to obtain the optimum geometry structures using the wB97XD functional. The natural bond orbital (NBO) analysis showed that the metal ion coordinates to the ligands through electron donation from lone pairs on nitrogen and oxygen atoms to the d orbitals of the metal ion. The topology analysis of the electron density by means of the natural bond orbitals (NBO), quantum theory of atoms in molecules (QTAIM), noncovalent index (NCI), and electron localization function (ELF) have revealed valuable information regarding the nature of interactions and the results are in good agreement with the structural analysis results.

Synthesis, Spectroscopic and X-Ray Structure Determination of a New Mononuclear Terbium (III) Complex from the Ligand N,N'-1,5-bis(pyridylmethylidene) Carbonohydrazone (H2L)

In the title compound, [Tb(H2L)2(H2O)3].3Cl.4(H2O).(C2H5OH), the Tb3+ is nine-coordinated in a distorted monocapped square antiprismgeometry by four nitrogen atoms, two oxygen atoms from the ligand molecules of the tridentate N,N'-1,5-bis(pyridylmethylidene) carbonohydrazone) (H2L) and three oxygen atoms of coordinating water molecules. The structure of the complex was elucidated by X-ray diffraction analysis. Suitable crystals were grown by slow evaporation of ethanol solution. The compound crystallizes in the triclinic crystal system with a space group of Pī. The asymmetric unit of the compound contains two neutral ligand molecules, oneterbium ion, three coordinated water molecules, five and half uncoordinated water molecules and one uncoordinated ethanol molecule. In the crystal, the complex cations are linked by hydrogen bonds into layers. These layers, chloride anions and non-coordinating water molecules are connected by O—H···O, O—H···N, O—H···Cl, N—H···O, N—H···Cl and C—H···Cl hydrogen bonds into a three-dimensional structure.

A water-stable dual-responsive Cd-CP for fluorometric recognition of hypochlorite and acetylacetone in aqueous media

One novel cadmium(II)-coordination polymer [Cd3L2(datrz)(H2O)3] (CP 1) is controllably synthesized by surmising the astute combination of semi-rigid tricarboxylate acid 4-(2′,3′-dicarboxylphenoxy) benzoic acid (H3L) and auxiliary ligand 3,5-diamino-1,2,4-triazole (datrz). Structure analysis shows that CP 1 has a two-dimensional (2D) layer structure with a 5-nodal (43) (44·62) (45·64·8) (45·6) (47·66·82) topology. Further investigations reveal that CP 1 shows superordinary water stability and good thermal stability. The fluorescent explorations suggest that the as-synthesized CP 1 could emit blue light centered at 485 nm, attributing to ligand-based emission. In terms of sensing investigations, CP 1 could act as a fluorescent sensor for detecting hypochlorite (ClO−) and acetylacetone (acac) through fluorescence turn-off process in aqueous solution, and the detection limit could reach 0.18 μM and 0.056 μM, respectively. Further research reveals that it is more likely the N–H···O–Cl hydrogen bonds between –NH2 groups of the triazole ligands and O atoms of ClO− plays the key role in the system, which may serve as a bridge for the energy transfer, leading to fluorescence quenching of the chemosensor. While the photoinduced electron transfer (PET) combined with inner filter effect (IFT) should be responsible for the turn-off fluorescence of CP 1 triggered by acac.