Extensive Intermolecular Hydrogen Bonds Research Articles

Structure and magnetic properties of two new lanthanide complexes with the 1-((E)-2-pyridinylmethylidene)semicarbazone ligand

Two novel semicarbazone-lanthanide(III) complexes were prepared and structurally characterized as [Ln (Hscpy)2 (NO3)2]NO3·MeOH (Ln = Gd and Tb; Hscpy = 1-((E)-2-pyridinylmethylidene)semicarbazone). The 4f metal ions experience deca-coordination geometry. Each molecular formula contains two neutral Hscpy molecules in the keto form coordinated through two nitrogen atoms and one oxygen atom, while two nitrate ligands are both coordinated in a chelate mode. The 1 + charge of the cation-complex is balanced by a nitrate anion. Extensive intermolecular hydrogen bonds are formed through the methanol solvate molecule, which acts both as a donor and an acceptor molecule. The chemical composition of the compounds was confirmed by high resolution mass spectra (ESI-MS); peaks at m/z = 122.07 and 148.05, assigned to the fragments C6H8N3+ and C7H6N3O+, respectively, are in agreement with the coordination of Hscpy. Alternating current magnetic susceptibility analysis was performed in the 10–10000 Hz range, and the terbium-complex showed slow relaxation of the magnetization when immersed in a static magnetic field of 1 kOe and 1.5 kOe, with an activation barrier to the relaxation (21.9(4) cm−1) among the highest found for ten-coordinated Tb(III) complexes. This behavior of slow relaxation of the magnetization is relevant as a memory effect regarding the development of Single Molecule Magnets (SMM).

Towards thermoplastic hemicellulose: Chemistry and characteristics of poly-(ε-caprolactone) grafting onto hemicellulose backbones

Hemicellulose is a highly available polysaccharide but with poor industrial applications attributed mainly to difficulties in processability, owing to extensive intermolecular hydrogen bonds. In the current study, hemicellulose was subjected to a chemical modification by ring-opening graft polymerization of ε-caprolactone (CL) to improve its processability for value-added applications. Hemicellulose-graft-poly-(ε-caprolactone) (HCgPCL) copolymers were synthesized using 1,5,7-triazabicyclodecene [4.4.0] (TBD) as an organic catalyst. The extent and length of grafted PCL sidechains in HCgPCL copolymers were controlled by adjusting the molar ratios of CL monomer to anhydroxylose residues. The various characterization analysis of the physicochemical and mechanical properties of HCgPCL materials revealed a successful grafting. The NMR analyses indicated that the degree of polymerization (DP) of the grafted PCL can range between 1.82 and 4.26 based on the changes in the molar ratio of the reactants. Furthermore, results indicated that the mechanical and the hydrophobic properties of the materials were enhanced by PCL grafting onto hemicellulose. Finally, biodegradability measurements indicated a remarkable (95.3–99.7%) materials biodegradation. We anticipate that the HCgPCL copolymers will have great potential to be an eco-friendly part of the bioplastic industry.

Copper(II) complexes with an arylhydrazone of methyl 2-cyanoacetate as effective catalysts in the microwave-assisted oxidation of cyclohexane

Abstract Reaction of sodium (E/Z)-2-(2-(1-cyano-2-methoxy-2-oxoethylidene)hydrazinyl)benzene-sulfonate (NaHL) with copper(II) nitrate hydrate in the presence of imidazole (im) in methanol affords [CuL(im)(H2O)] (1). Complex 1 is characterized by IR spectroscopy and ESI-MS spectrometry, elemental and single crystal X-ray crystal structural analyses. The coordination environment of the central copper(II) is nearly intermediate between ideal square-based pyramidal and trigonal bipyramidal geometry, three sites being occupied by the L2− ligand, which chelates in the O, N, O fashion, while two other sites are filled with the water and imidazole molecules. Extensive intermolecular hydrogen bonds between the L2−, water and imidazole ligands lead to a 3D supramolecular network. 1 and known Cu(II) complexes [Cu(H2O)2L]·H2O (2), [Cu(H2O)(py)L]·H2O (3) and [Cu3(µ3-OH)(NO3)(CH3OH)(µ2-X)3(µ2-HL)] (4) act as effective catalysts in the oxidation of cyclohexane to cyclohexanol and cyclohexanone, using low power microwave (MW) irradiation, under mild conditions. Without a promoter, the activity of the catalyst reached a turnover number of 1.44 × 103 and a turnover frequency of 1.98 × 103 h−1, after 2 h, at 50 °C.

Steric repulsion and supra-molecular assemblies via a two-dimensional plate by C-H⋯O hydrogen bonds in two closely related 2-(benzo-furan-2-yl)-2-oxoethyl benzoates.

2-(Benzo-furan-2-yl)-2-oxoethyl 2-chloro-benzoate, C17H11ClO4 (I), and 2-(benzo-furan-2-yl)-2-oxoethyl 2-meth-oxy-benzoate, C18H14O5 (II), were synthesized under mild conditions. Their chemical and mol-ecular structures were analyzed by spectroscopic and single-crystal X-ray diffraction studies, respectively. These compounds possess different ortho-substituted functional groups on their phenyl rings, thus experiencing extra steric repulsion force within their mol-ecules as the substituent changes from 2-chloro (I) to 2-meth-oxy (II). The crystal packing of compound (I) depends on weak inter-molecular hydrogen bonds and π-π inter-actions. Mol-ecules are related by inversion into centrosymmetric dimers via C-H⋯O hydrogen bonds, and further strengthened by π-π inter-actions between furan rings. Conversely, mol-ecules in compound (II) are linked into alternating dimeric chains propagating along the [101] direction, which develop into a two-dimensional plate through extensive inter-molecular hydrogen bonds. These plates are further stabilized by π-π and C-H⋯π inter-actions.

Influence of Hydrogen Bonding on the Surface Diffusion of Molecular Glasses: Comparison of Three Triazines.

Surface grating decay measurements have been performed on three closely related molecular glasses to study the effect of intermolecular hydrogen bonds on surface diffusion. The three molecules are derivatives of bis(3,5-dimethyl-phenylamino)-1,3,5-triazine and differ only in the functional group R at the 2-position, with R being C2H5, OCH3, and NHCH3, and referred to as "Et", "OMe", and "NHMe", respectively. Of the three molecules, NHMe forms more extensive intermolecular hydrogen bonds than Et and OMe and was found to have slower surface diffusion. For Et and OMe, surface diffusion is so fast that it replaces viscous flow as the mechanism of surface grating decay as temperature is lowered. In contrast, no such transition was observed for NHMe under the same conditions, indicating significantly slower surface diffusion. This result is consistent with the previous finding that extensive intermolecular hydrogen bonds slow down surface diffusion in molecular glasses and is attributed to the persistence of hydrogen bonds even in the surface environment. This result is also consistent with the lower stability of the vapor-deposited glass of NHMe relative to those of Et and OMe and supports the view that surface mobility controls the stability of vapor-deposited glasses.

Crystal structure of a DNA aptamer bound to PvLDH elucidates novel single-stranded DNA structural elements for folding and recognition.

Structural elements are key elements for understanding single-stranded nucleic acid folding. Although various RNA structural elements have been documented, structural elements of single-stranded DNA (ssDNA) have rarely been reported. Herein, we determined a crystal structure of PvLDH in complex with a DNA aptamer called pL1. This aptamer folds into a hairpin-bulge contact by adopting three novel structural elements, viz, DNA T-loop-like motif, base–phosphate zipper, and DNA G·G metal ion zipper. Moreover, the pL1:PvLDH complex shows unique properties compared with other protein:nucleic acid complexes. Generally, extensive intermolecular hydrogen bonds occur between unpaired nucleotides and proteins for specific recognitions. Although most protein-interacting nucleotides of pL1 are unpaired nucleotides, pL1 recognizes PvLDH by predominant shape complementarity with many bridging water molecules owing to the combination of three novel structural elements making protein-binding unpaired nucleotides stable. Moreover, the additional set of Plasmodium LDH residues which were shown to form extensive hydrogen bonds with unpaired nucleotides of 2008s does not participate in the recognition of pL1. Superimposition of the pL1:PvLDH complex with hLDH reveals steric clashes between pL1 and hLDH in contrast with no steric clashes between 2008s and hLDH. Therefore, specific protein recognition mode of pL1 is totally different from that of 2008s.

Synthesis, crystal structure, photoluminescence property of a series of 3d–4f coordination supramolecular complexes

A series of 3d–4f heterobinuclear complexes were constructed by employing the 2,2′-bipy (2,2′-bipy=2,2′-bipyridine) ligand and corresponding metal ions (MII/LnIII, M=CoII, CuII and ZnII; LnIII=NdIII, SmIII, EuIII and TbIII). Elemental analyses, IR, UV–vis–NIR spectra, PXRD and single crystal X-ray diffraction analysis reveal that complexes 1–4, 5–8, and 9–12 are isomorphous, respectively. The zero-dimensional structures are further connected to 2D or 3D supramolecular network structures via extensive intermolecular hydrogen bonds. Luminescence studies for the heterobinuclear complexes containing SmIII, EuIII and TbIII reveal that the chromophoric composed of ZnII/L may efficiently sensitize the luminescence of the rare earth cations which acts as an antenna, whereas the existence of CuII leads to the quenching of the luminescence of LnIII ions.

First-principles high-pressure unreacted equation of state and heat of formation of crystal 2,6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105).

We report dispersion-corrected density functional theoretical calculations of the unreacted equation of state (EOS) of crystal 2,6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105) under hydrostatic compression of up to 45 GPa. Convergence tests for k-points sampling in the Brillouin zone show that a 3 × 1 × 2 mesh is required to reproduce the X-ray crystal structure at ambient conditions, and we confirm our finding with a separate supercell calculation. Our high-pressure EOS yields a bulk modulus of 19.2 GPa, and indicates a tendency towards anisotropic compression along the b lattice vector due to molecular orientations within the lattice. We find that the electronic energy band gap decreases from a semiconductor type of 1.3 eV at 0 GPa to quasi-metallic type of 0.6 eV at 45 GPa. The extensive intermolecular hydrogen bonds involving the oxide (-NO) and dioxide (-NO2) interactions with the amine (-NH2) group showed enhanced interactions with increasing pressure that should be discernible in the mid IR spectral region. We do not find evidence for structural phase transitions or chemically induced transformations within the pressure range of our study. The gas phase heat of formation is calculated at the G4 level of theory to be 22.48 kcal/mol, while we obtain 25.92 kcal/mol using the ccCA-PS3 method. Density functional theory calculations of the crystal and the gas phases provided an estimate for the heat of sublimation of 32.4 kcal/mol. We thus determine the room-temperature solid heat of formation of LLM-105 to be -9.9 or -6.5 kcal/mol based on the G4 or ccCA-PS3 methods, respectively.

Isolation and structural and pharmacological characterization of α-elapitoxin-Dpp2d, an amidated three finger toxin from black mamba venom.

We isolated a novel, atypical long-chain three-finger toxin (TFT), α-elapitoxin-Dpp2d (α-EPTX-Dpp2d), from black mamba (Dendroaspis polylepis polylepis) venom. Proteolytic digestion with trypsin and V8 protease, together with MS/MS de novo sequencing, indicated that the mature toxin has an amidated C-terminal arginine, a posttranslational modification rarely observed for snake TFTs. α-EPTX-Dpp2d was found to potently inhibit α7 neuronal nicotinic acetylcholine receptors (nAChR; IC₅₀, 58 ± 24 nM) and muscle-type nAChR (IC₅₀, 114 ± 37 nM) but did not affect α3β2 and α3β4 nAChR isoforms at 1 μM concentrations. Competitive radioligand binding assays demonstrated that α-EPTX-Dpp2d competes with epibatidine binding to the Lymnea stagnalis acetylcholine-binding protein (Ls-AChBP; IC₅₀, 4.9 ± 2.3 nM). The activity profile and binding data are reminiscent of classical long-chain TFTs with a free carboxyl termini, suggesting that amidation does not significantly affect toxin selectivity. The crystal structure of α-EPTX-Dpp2d was determined at 1.7 Å resolution and displayed a dimeric toxin assembly with each monomer positioned in an antiparallel orientation. The dimeric structure is stabilized by extensive intermolecular hydrogen bonds and electrostatic interactions, which raised the possibility that the toxin may exist as a noncovalent homodimer in solution. However, chemical cross-linking and size-exclusion chromatography coupled with multiangle laser light scattering (MALLS) data indicated that the toxin is predominantly monomeric under physiological conditions. Because of its high potency and selectivity, we expect this toxin to be a valuable pharmacological tool for studying the structure and function of nAChRs.

Synthesis, structure, spectral, thermal analyses and DFT calculation of a hydrogen bonded crystal: 2-Aminopyrimidinium dihydrogenphosphate monohydrate

A proton transfer complex of 2-aminopyrimidine with phosphoric acid was synthesized and crystallized. Single crystal X-ray studies, the vibrational spectral analysis using Laser Raman and FT-IR spectroscopy in the range of 4000–400cm−1, UV–Vis-NIR studies and thermogravimetric analyses were carried out in the solid crystalline form. The single crystal X-ray studies shows that the crystal packing is dominated by NH⋯O and OH⋯O hydrogen bonds leading to a hydrogen bonded ensemble. The two dimensional cationic layers, connected through the centrosymmetric anionic dimer of R22(8) motif, is extending along ab plane of the crystal leading to zig-zag infinite chain C21(6) and C22(6) motifs. To investigate the strength of the hydrogen bonds, vibrational spectral studies were adopted and the shifting of bands due to the intermolecular interactions were analyzed. Density Functional Theory (DFT) using the B3LYP function with the 6-311++G(d,p) basis set was applied to the solid state molecular geometry obtained from single crystal X-ray studies. The optimized molecular geometry and computed vibrational spectra are compared with experimental results which shows appreciable agreement. NBO analysis has been carried out by DFT level. In this study explains charge delocalization of the present molecule which shows the possible biological/pharmaceutical activity of the molecule. The number of normal modes were also attempted by the factor group analysis method. It is evident that the influence of extensive intermolecular hydrogen bonds reduces the Td symmetry of the phosphate anion to the lower C2v symmetry. The existence of exothermic peaks in DTA iterate the breaking of intermolecular hydrogen bonds and the phase change of the crystal. The presence of water molecule is also confirmed in the thermal analyses.

Eight supramolecular assemblies constructed from bis(benzimidazole) and organic acids through strong classical hydrogen bonding and weak noncovalent interactions

Eight crystalline organic acid–base adducts derived from alkane bridged bis(N-benzimidazole) and organic acids (2,4,6-trinitrophenol, p-nitrobenzoic acid, m-nitrobenzoic acid, 3,5-dinitrobenzoic acid, 5-sulfosalicylic acid and oxalic acid) were prepared and characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. Of the eight compounds five are organic salts (1, 4, 6, 7 and 8) and the other three (2, 3, and 5) are cocrystals. In all of the adducts except 1 and 8, the ratio of the acid and the base is 2:1. All eight supramolecular assemblies involve extensive intermolecular classical hydrogen bonds as well as other noncovalent interactions. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. These weak interactions combined, all the complexes displayed 3D framework structure. The results presented herein indicate that the strength and directionality of the classical N+–H⋯O−, O–H⋯O, and O–H⋯N hydrogen bonds (ionic or neutral) and other nonbonding associations between acids and ditopic benzimidazoles are sufficient to bring about the formation of cocrystals or organic salts.

Solubility and Surface Interactions of RF Plasma Polymerized Polyterpenol Thin Films

Organic thin films have myriad of applications in biological interfaces, micro-electromechanical systems and organic electronics. Polyterpenol thin films fabricated via RF plasma polymerization have been substantiated as a promising gate insulating and encapsulating layer for organic optoelectronics, sacrificial place-holders for air gap fabrication as well as antibacterial coatings for medical implants. This study aims to understand the wettability and solubility behavior of the nonsynthetic polymer thin film, polyterpenol. Polyterpenol exhibited monopolar behavior, manifesting mostly electron donor properties, and was not water soluble due to the extensive intermolecular and intramolecular hydrogen bonds present. Hydrophobicity of polyterpenol surfaces increased for films fabricated at higher RF power attributed to reduction in oxygen containing functional groups and increased cross linking. The studies carried out under various deposition conditions vindicate that we could tailor the properties of the polyterpenol thin film for a given application.

Crystal Structure and Photoluminescence Properties of Gadolinium Picrate Triethylene Glycol Complex

The [Gd(Pic)2(H2O)(EO3)](Pic)·CH3OH complex, where EO3 = triethylene glycol, and Pic = picrate anion, has been prepared and characterized. The complex is crystallized in triclinic with space group P-1. The Gd(III) ion is coordinated to nine donor oxygen atoms from one EO3 ligand, two Pic anions and one water molecule. The geometric arrangement of the heavier lanthanide–picrate complex is different with the lighter lanthanide–picrate complexes as observed. The charge balancing and steric hindrance of the bulky of picrate anion have influenced the geometric arrangement in the inner-sphere. Two intramolecular hydrogen bonds O1–H1O1···O26 and C6–H6A···O13 help in stabilizing of complex. Extensive intermolecular hydrogen bonds O–H···O and C–H···O linked the molecules into two-dimensional layer and parallel to the (011) plane as observed. No metal centered emission can be observed for the Gd complex. The phosphorescence spectrum of Gd complex in the solid state showed the central peak at 537.8 nm which related to the emission of the picrate anion. The [Gd(Pic)2(H2O)(EO3)](Pic)·CH3OH complex was synthesized. The Gd(III) ion is coordinated to nine donor oxygen atoms. The steric hindrance of the bulky of picrate anion have influenced the inner-sphere. Extensive intermolecular hydrogen bonds linked the molecules into two-dimensional layer. No metal centered emission can be observed for the Gd complex.

Synthesis and characterization of an energetic compound Cu(Mtta)2(NO3)2 and effect on thermal decomposition of ammonium perchlorate

An energetic coordination compound Cu(Mtta)2(NO3)2 has been synthesized by using 1-methyltetrazole (Mtta) as ligand and its structure has been characterized by X-ray single crystal diffraction. The central copper (II) cation was coordinated by four O atoms from two Mtta ligands and two N atoms from two NO3− anions to form a six-coordinated and distorted octahedral structure. 2D superamolecular layer structure was formed by the extensive intermolecular hydrogen bonds between Mtta ligands and NO3− anions. Thermal decomposition process of the compound was predicted based on DSC and TG-DTG analyses results. The kinetic parameters of the first exothermic process of the compound were studied by the Kissinger's and Ozawa–Doyle's methods. Sensitivity tests revealed that the compound was insensitive to mechanical stimuli. In addition, compound was explored as additive to promote the thermal decomposition of ammonium perchlorate (AP) by differential scanning calorimetry.

Syntheses, structures, and luminescent properties of lanthanide complexes with N,N′-bis(p-methoxyphenyl)-3-oxapentanediamide

An amide-type acyclic polyether, N,N′-bis(p-methoxyphenyl)-3-oxapentanediamide (L), and its three lanthanide coordination compounds, [Ln(NO3)(L)2(H2O)2] · (NO3)2 [Ln = Pr (1), Nd (2), and Dy (3)], have been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis, and X-ray diffraction. Single crystal X-ray structure analyses reveal that 1 and 2 have the same structure and crystallize in the monoclinic crystal system with C2/c space group. The coordination geometry around the central atom is a distorted bicapped square antiprism. Extensive intermolecular hydrogen bonds in 1 and 2 result in 3-D supramolecular networks. Complex 3 exhibits luminescence in the visible region upon excitation with UV-rays.

Synthesis, Crystal Structure, and Thermal Properties of the Energetic Coordination Compound [Co(DAT)2(H2O)4](HTNR)2·2H2O (DAT = 1,5‐diaminotetrazole)

AbstractA new coordination complex, [Co(DAT)2(H2O)4](HTNR)2·2H2O [DAT = 1,5‐diaminotetrazole, HTNR = 2,4,6‐trinitroresorcinol (styphnic acid)], was obtained in high yield and characterized by elemental analysis and Fourier‐transform infrared (FT‐IR) spectroscopy. The molecular structure of [Co(DAT)2(H2O)4](HTNR)2·2H2O in the crystalline state is determined by X‐ray crystallography is as follows: monoclinic, C2/c, a = 19.216(3) Å, b = 5.4992(8) Å, c = 30.418(5) Å, β = 104.500(5), V = 3112.0(8) Å3, Z = 4, ρcalc. = 1.851 g·cm–3, R1 = 0.0271 and wR2 = (all data) 0.0674. The central cobalt(II) cation is coordinated by two nitrogen atoms of two DAT and four oxygen atoms of four H2O ligand molecules to form a six‐coordinate and slightly distorted octahedral structure. Extensive intermolecular hydrogen bonds link molecular units of [Co(DAT)2(H2O)4(HTNR)2·2H2O together to form a 3D net structure with pore canals. The thermal decomposition mechanism for the title compound was predicted based on DSC, TG‐DTG, and FT‐IR analyses and non‐kinetic parameters of the first exothermic process were estimated by applying the Kissinger, Starink, and Ozawa–Doyle methods.

Crystal Structure, Thermal Decomposition Behaviors and Sensitivity Properties of a Novel Energetic Compound [Co(DAT)6] (ClO4)2

AbstractA novel energetic coordination compound [Co(DAT)6](ClO4)2 has been synthesized by using 1,5‐diaminotetrazole (DAT) as a ligand and its structure has been characterized using X‐ray single crystal diffraction, elemental analysis and FT‐IR spectroscopy. The central cobalt(II) cation is coordinated by six N atoms from six DAT molecules to form a six‐coordinated and distorted octahedral structure. Di‐dimension layer structure was formed by the extensive intermolecular hydrogen bonds between DAT ligands and ClO−4 anions along a‐axis and b‐axis. Thermal decomposition mechanism of [Co(DAT)6](ClO4)2 was investigated based on differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared (FT‐IR) spectra. The kinetic parameters of the first exothermic process were studied by applying the Kissinger's and Ozawa‐Doyle's methods. Additionally, the sensitivities of this complex were tested. The results of all the studies show that [Co(DAT)6](ClO4)2 has an extreme potential application as an energetic material.

A New Series Lanthanide-2,6-Pyridinedicarboxylic Acid Complexes Containing Low Dimensionality: Synthesis, Structure and Photoluminescent Properties

Based on the 2,6-pyridinedicarboxylate acid ligand, ten lanthanide complexes with formula, (Hdipa)3[Ln(L)3] (Ln = Eu [1], Gd [2], Nd [3], Tb [4], Ce [5], Sm [6], Pr [7], Dy [8] and Er [9]) and [Nd(L)(HL)(H2O)2]·4H2O (10), (where H2L = 2,6-pyridinedicarboxylic acid and dipa = N-(1-methylethyl)-2-propanamine) have been prepared by different synthetic methods. Structural analyses reveal that complexes 1–3 are isomorphous, zero-dimensional structures, which are further connected to 3D H-bonding networks via extensive intermolecular hydrogen bonds. In the structures of these complexes, the dipa plays a key role in balancing electric charge. For complex 10, the 1D Ln–O–C–O–Ln polymeric chains are linked into a stable 3D H-bonding framework through numerous intermolecular and intramolecular hydrogen bonds. The luminescent properties of complexes 1, 4, 6 and 8 were investigated in detail. Based on the 2,6-pyridinedicarboxylate acid ligand, ten lanthanide complexes with formula, (Hdipa)3[Ln(L)3] (Ln = Eu [1], Gd [2], Nd [3], Tb [4], Ce [5], Sm [6], Pr [7], Dy [8] and Er [9]) and [Nd(L)(HL)(H2O)2]·4H2O (10), (where H2L = 2,6-pyridinedicarboxylic acid and dipa = N-(1-methylethyl)-2-propanamine) have been prepared by different synthetic methods. Complexes 1–9 are zero structures and 10 features a 1D Ln–O–C–O–Ln polymeric chain structure. The luminescent properties of complexes 1, 4, 6 and 8 were investigated in detail.

Synthesis, structural investigation, thermal decomposition mechanism and sensitivity properties of an energetic compound [Cd(DAT) 6](ClO 4) 2 (DAT = 1,5-diaminotetrazole)

An energetic coordination compound [Cd(DAT) 6](ClO 4) 2 has been synthesized by using 1,5-diaminotetrazole (DAT) as ligand and its structure has been characterized by applying X-ray single crystal diffraction, elemental analysis and FT-IR spectroscopy. The central cadmium(II) cation is coordinated by six N atoms from six DAT molecules to form a six-coordinated and distorted octahedral structure. Di-dimension layer structure was formed and the layers were linked together by the extensive intermolecular hydrogen bonds between DAT ligands and ClO 4 − anions. Thermal decomposition mechanism of the title compound was predicted based on DSC, TG-DTG and FT-IR analyses results. The kinetic parameters of the first exothermic process of the title compound were studied by applying the Kissinger's and Ozawa–Doyle's methods. Sensitivity tests reveal that the title compound has sensitive nature.

Synthesis, structural investigation and thermal analyses of a novel coordination compound [Cd(DAT) 6](HTNR) 2·3.5H 2O (DAT = 1,5-diaminotetrazole, H 2TNR = styphnic acid)

A novel coordination compound [Cd(DAT) 6](HTNR) 2·3.5H 2O has been synthesized by using 1,5-diaminotetrazole (DAT) as ligand and characterized by applying X-ray single crystal diffraction, elemental analysis and FT-IR spectroscopy. The central cadmium (II) cation is coordinated by six N atoms of six DAT ligand molecules to form a six-coordinated and slightly distorted octahedral structure. With the extensive intermolecular hydrogen bonds, molecular units of [Cd(DAT) 6](HTNR) 2·3.5H 2O are linked together to form a 3D net structure with pore canals. Mulliken charge distribution of DAT in bulk state has been obtained from the density functional theory (DFT) with the B3LYP method employing the 6-31G ∗∗ basis sets to interpret the reason why the coordination site of DAT is N(4) atom of the tetrazole ring. Thermal decomposition mechanism of the title compound was predicted based on DSC, TG-DTG and FT-IR analyses results. The kinetic parameters of the first exothermic process of the title compound were studied by applying the Kissinger’s and Ozawa–Doyle’s methods.