Crystallization Water Molecules Research Articles

Trifluoromethanesulfonate salt of 5,10,15,20-tetrakis(1-benzylpyridin-1-ium-4-yl)-21H,23H-porphyrin and its CaII complex

The synthesis, crystallization and characterization of a trifluoromethanesulfonate salt of 5,10,15,20-tetrakis(1-benzylpyridin-1-ium-4-yl)-21H,23H-porphyrin, C68H54N8 4+·4CF3SO3 −·4H2O, 1·OTf, are reported in this work. The reaction between 5,10,15,20-tetrakis(pyridin-4-yl)-21H,23H-porphyrin and benzyl bromide in the presence of 0.1 equiv. of Ca(OH)2 in CH3CN under reflux with an N2 atmosphere and subsequent treatment with silver trifluoromethanesulfonate (AgOTf) salt produced a red–brown solution. This reaction mixture was filtered and the solvent was allowed to evaporate at room temperature for 3 d to give 1·OTf. Crystal structure determination by single-crystal X-ray diffraction (SCXD) revealed that 1·OTf crystallizes in the space group P21/c. The asymmetric unit contains half a porphyrin molecule, two trifluoromethanesulfonate anions and two water molecules of crystallization. The macrocycle of tetrapyrrole moieties is planar and unexpectedly it has coordinated CaII ions in occupational disorder. This CaII ion has only 10% occupancy (C72H61.80Ca0.10F12N8O16S4). The pyridinium rings bonded to methylene groups from porphyrin are located in two different arrangements in almost orthogonal positions between the plane formed by the porphyrin and the pyridinium rings. The crystal structure features cation...π interactions between the CaII atom and the π-system of the phenyl ring of neighboring molecules. Both trifluoromethanesulfonate anions are found at the periphery of 1, forming hydrogen bonds with water molecules.

A nanochanneled silver-deficient oxalatocobaltate(III) complex anion with hydronium as counter cation: synthesis, crystal structure, thermal analysis and magnetism

A novel cobalt(III) salt, (H3O)0.6[Ag2.4Co(C2O4)3]∙6H2O (1), a member of the rare paramagnetic CoIII-open framework materials, has been synthesized in water and characterized by standard methods, including elemental and thermal analyses, IR, UV-Vis and EDX spectroscopies, and single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic I2/a space group. In the crystal structure, the Co(III) centers are pseudo-octahedrally chelated by three oxalato ligands with usual propeller orientation. The structure can be best described as an anionic silver-deficient oxalatocobaltate(III) [Ag2.4Co(C2O4)3]0.6- framework with isolated nanochannels parallel to the a axis, hosting highly disordered water molecules carrying protons (hydronium ions). Thermal analysis showed significant weight losses corresponding to the elimination of crystal water molecules followed by the decomposition of the network. Temperature-dependence susceptibility measurements investigated in the temperature range 2–300 K revealed antiferromagnetic ordering at low temperatures (T ≤ 25 K), the Curie–Weiss constants being C = 1.60 emu∙Oe−1∙K and θ = -50 K.

Bis(2-hy-droxy-2,3-di-hydro-1H-inden-1-aminium) tetra-chlorido-palladate(II) hemihydrate.

A new square-planar palladium complex salt hydrate, (C9H12NO)2[PdCl4]·0.5H2O, has been characterized. The asymmetric unit of the complex salt comprises two [PdCl4]2- dianions, four 2-hy-droxy-2,3-di-hydro-1H-inden-1-aminium cations, each derived from (1R,2S)-(+)-1-amino-indan-2-ol, and one water mol-ecule of crystallization. In the crystal, a two-dimensional layer parallel to (001) features a number of O-H⋯O, N-H⋯O, O-H⋯Cl and N-H⋯Cl hydrogen bonds.

Synthesis and crystal structure of a cadmium(II) coordination polymer based on 4,4′-(1H-1,2,4-triazole-3,5-diyl)dibenzoate

The asymmetric unit of the title compound, catena-poly[[[aquabis(pyridine-κN)cadmium(II)]-μ2-4,4′-(1H-1,2,4-triazole-3,5-diyl)dibenzoato-κ4 O,O′:O′′,O′′′] 4.5-hydrate], {[Cd(C16H9N3O4)(C5H5N)2(H2O)]·4.5H2O} n or {[Cd(bct)(py)2(H2O)]·4.5H2O} n (I), consists of a Cd2+ cation coordinated to one bct2– carboxylate dianion, two molecules of pyridine and a water molecule as well as four and a half water molecules of crystallization. The metal ion in I possesses a pentagonal–bipyramidal environment with the four O atoms of the two bidentately coordinated carboxylate groups and the N atom of a pyridine molecule forming the O4N equatorial plane, while the N atom of another pyridine ligand and the O atom of the water molecule occupy the axial positions. The bct2– bridging ligand connects two metal ions via its carboxylic groups, resulting in the formation of a parallel linear polymeric chain running along the [1\overline{1}1] direction. The coordinated water molecule of one chain forms a strong O—H...O hydrogen bond with the carboxylate O atom of a neighboring chain, leading to the formation of double chains with a closest distance of 5.425 (7) Å between the cadmium ions belonging to different chains. Aromatic π–π stacking interactions between the benzene fragments of the anions as well as between the coordinated pyridine molecules belonging to different chains results in the formation of sheets oriented parallel to the (\overline{1}01) plane. As a result of hydrogen-bonding interactions involving the water molecules of crystallization, the sheets are joined together in a three-dimensional network.

Tetra-aqua-(ethane-1,2-di-amine-κ2N,N')nickel(II) naphthalene-1,5-di-sulfonate dihydrate.

The reaction of ethane-1,2-di-amine (en, C2H8N2), the sodium salt of naphthalene-1,5-di-sulfonic acid (H2NDS, C10H8O6S2), and nickel sulfate in an aqueous solution resulted in the formation of the title salt, [Ni(C2H8N2)(H2O)4](C10H6O6S2)·2H2O or [Ni(en)(H2O)4](NDS)·2H2O. In the asymmetric unit, one half of an [Ni(en)(H2O)4]2+ cation and one half of an NDS2- anion, and one water mol-ecule of crystallization are present. The Ni2+ cation in the complex is positioned on a twofold rotation axis and exhibits a slight tetra-gonal distortion of the cis-NiO4N2 octa-hedron, with an Ni-N bond length of 2.0782 (16) Å, and Ni-O bond lengths of 2.1170 (13) Å and 2.0648 (14) Å. The anion is completed by inversion symmetry. In the extended structure, the cations, anions, and non-coordinating water mol-ecules are connected by inter-molecular N-H⋯O and O-H⋯O hydrogen bonding, as well as C-H⋯π inter-actions, forming a three-dimensional network.

EXO-LIGAND COMPLEXES OF DIETHYLENTRIAMINE-PENTAACETATOGERMANATIC(IV) ACID

The synthesis of complexes based on diethylenetriaminepenta-acetategermanate(IV) acid and a number of exo-ligands was carried out. Their composition, thermal stability, method of coordination of diethylenetriaminepentaacetic acid (H5Dtpa) and protonation of exo-ligands (isoniazid Ind, diphenylguanidine Dphg, piracetam Pam, imidazole Im, cytosine Ctz, 1,10-phenanthroline Phen, 2,2´-bipyridine Bipy), were established. The structural scheme and molecular formula of the obtained compounds were proposed (HL)[Ge(OH)(HDtpa)]·nH2O, де L = Ind, n = 0 (1), Dphg, n = 8 (2), Pam, n = 4 (3), Im, n = 2 (4), Ctz, n = 2 (5), Phen, n = 5 (6), Bipy, n = 4 (7). Based on the elemental analysis of the synthesis products 1–7, it was determined that they exhibit a molar ratio of Ge:N = 1:6 (1, 2, 5), Ge:N = 1:5 (3, 4, 6, 7), therefore, Ge:Dtpa:Ind (Dphg, Pam, Im, Ctz, Phen, Bipy) = 1:1:1. The thermal decomposition of complexes 2–7 begins with an endothermic effect in the temperature range of 80–180 °C, during which a certain amount of crystallization water molecules is removed. The relatively high temperature of its removal is due to the formation of a broad system of intermolecular and intramolecular hydrogen bonds, which is characteristic of various metal complexonates. Thus, in the new compounds, the structure of the octahedral polyhedron of Germanium remains the same as in the original complex acid: the Ge atom is coordinated by two Nitrogen atoms and three Oxygen atoms of three Dtpa acetate groups. The coordination number of Germanium is complemented to 6 by the hydroxo-ligand. All carboxyl groups of the ligand are deprotonated, as evidenced by the presence of bands νas(COO⁻) at 1630–1690 cm⁻¹ and νs(COO⁻) at 1380–1420 cm⁻¹. The presence of Ge-N and Ge-O bonds in the synthesized complexes is confirmed by the bands of valence vibrations of these bonds in the range of 640–650 cm⁻¹ and 590–620 cm⁻¹, respectively. Particularly noteworthy is the band of deformation vibrations of the Ge-O-N group at 810–820 cm⁻¹. In complexes 1–7, a splitting of bands in the 3000 cm⁻¹ region (valence vibrations of the C-H bond) is observed, indicating that all nitrogen atoms in their molecules are coordinated or protonated. The obtained compounds are of interest as promising agents for biomedical applications.

Poly[[(μ3-adamantane-1,3-di-acetato)[μ-N-(pyridin-3-yl)isonicotinamide]-nickel(II)] monohydrate], a layered coordination polymer with triangular (3,6) topology.

The title compound, {[Ni(C14H18O4)(C11H9N3O)]·H2O}n, contains octa-hedrally coordinated NiII ions ligated by 1,3-adamantanedi-acetato (ada) ligands and N-(pyridin-3-yl)isonicotinamide (3-pina) ligands, to form coordination polymer layers with a triangular (3,6) grid topology based on [Ni2(OCO)2] dimeric units. The diperiodic layer motifs stack in an ABAB pattern mediated by C-H⋯O supra-molecular inter-actions between ada ligands and water mol-ecules of crystallization to form the full triperiodic crystal structure of the title compound.

Poly[[[μ-1,4-bis-(pyridin-4-ylmeth-yl)piperazine][μ-4-(2-carboxyl-atoeth-yl)benzoato]copper(II)] monohydrate], a coordination polymer with twofold inter-penetrated cds topology networks.

The title compound, {[Cu(C10H8O4)(C16H20N4)]·H2O}n, contains square-planar coordinated CuII ions linked by 4-(carboxyl-atoeth-yl)benzoato (ceb) and 1,4-bis-(pyridin-4-ylmeth-yl)piperazine (bpmp) ligands into a tri-periodic coordination polymer with twofold inter-penetrating 658 cds topology. Positional crystallographic disorder among the copper atoms, the ethyl-carb-oxy group of the ceb ligands, and the water mol-ecules of crystallization exists in a refined 0.655 (6)/0.345 (6) ratio.

Syntheses and Solid-State Characterizations of N-Alkylated Glycine Derivatives

Seven N-alkylated glycine derivatives were prepared and characterized using single-crystal X-ray diffraction, infrared spectroscopy and thermal analysis. Chloride salts, H2EtGlyCl, H2(n-PrGly)Cl and H2(i-PrGly)Cl were prepared by aminolysis of chloroacetic acid with respective alkylamine. Nitrate salts, H2EtGlyNO3, H2(i-PrGly)NO3, H2(n-PrGly)NO3 and zwitterionic compound H(n-PrGly)·1/3H2O were prepared using ion exchange reactions from corresponding chloride salts. In all the N-alkylated glycine chloride salts, two N-alkylglycinium cations and two chloride anions were connected into centrosymmetric dimers that were additionally hydrogen bonded into endless chains. In the nitrate salts, 2D networks of different topologies were formed through hydrogen bonds between nitrate anions and N-alkylglycinium cations. In compound H(n-PrGly)·1/3H2O, the zwitterionic N-(n-propyl)glycines and water molecules of crystallization were connected into the 3D hydrogen bond networks. Chloride salts have significantly more H⋯H and O⋯C contacts than nitrate salts. All chloride salts decompose in endothermic, while nitrate salts decompose in exothermic thermal events.

Dehydration-actuated single-molecule magnet behavior in a cyanide-bridged [Fe2Co2] cluster featuring zigzag structure

A rare zigzag cyanide-bridged tetranuclear complex, {[(Tp*)FeIII(CN)3]2[CoII(tphz)1/2(SCN)(MeOH)]2}·4H2O (1·4H2O) (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate, tphz = tetrapyridophenazine) was successfully isolated and characterized structurally and magnetically. Single-crystal structural analysis indicates the Fe3+ and Co2+ ions are linked by cyanides while the inverse two Co2+ are bridged by the pyrazine of tphz. Magnetic studies for 1·4H2O revealed the ferromagnetic coupling (JFeCo = +3.2 cm−1) between the Fe3+ and Co2+ ions and antiferromagnetic interaction (JCoCo = −2.7 cm−1) between the Co2+ ions of the cluster. After the release of crystallized water molecules, however, the magnetic behaviors were drastically tuned indicated by the notable changes in the magnetic couplings for FeIIICoII (JFeCo = +3.9 cm−1) and CoIICoII (JCoCo = −3.5 cm−1). Reduced magnetization reveals the uniaxial magnetic anisotropy of the dehydrated molecule with the zero-field splitting parameter D = −10.3 cm−1. Additionally, field-supported single-molecule magnet behavior was observed with the effective energy barrier Ueff = 38.2 K, making complex 1 the first example of a zigzag Fe2Co2 single-molecule magnet. This work provides not only a rare dynamic switching molecular complex but also highlights the important influence of guest water molecules in magnetic behaviors.

μ-1,6-Dioxo-1,6-di-phenyl-hexane-3,4-diolato-bis-[(2,2'-bi-pyridine)-chlorido-copper(II)] dihydrate.

The reaction of CuCl2 with 1,6-diphenyl-1,3,5,6-hexa-netetrone and 2,2'-bi-pyridine (bipy) in ethanol gave crystals of the corresponding bimetallic complex, [Cu2(C18H12O4)Cl2(C10H8N2)2]·2H2O. The mol-ecule is centrosymmetric with each CuII ion coordinated to two oxygen atoms from the tetronediate, two nitro-gen atoms from a bipy ligand and one coordinated chloride ion. A water mol-ecule of crystallization forms hydrogen bonds to the chloride ions, linking the mol-ecules into a chain parallel to the bc-face diagonal.

Crystal structure and Hirshfeld surface analysis of 2-amino-5-{(1E)-1-[(carbamo-thioyl-amino)-imino]eth-yl}-4-methyl-1,3-thia-zol-3-ium chloride monohydrate.

In the hydrated title salt, C7H12N5S2 +·Cl-·H2O, the asymmetric unit comprises one 2-amino-5-{(1E)-1-[(carbamo-thioyl-amino)-imino]-eth-yl}-4-methyl-1,3-thia-zol-3-ium cation, one chloride anion and one water mol-ecule of crystallization. The cation is nearly flat (r.m.s. deviation of non-H atoms is 0.0814 Å), with the largest deviation of 0.1484 (14) Å observed for one of the methyl C atoms. In the crystal, the cations are linked by O-H⋯Cl, N-H⋯Cl, N-H⋯O, N-H⋯S and C-H⋯S hydrogen bonds, forming a tri-periodic network. The most important contributions to the crystal packing are from H⋯H (35.4%), S⋯H/H⋯S (24.4%), N⋯H/H⋯N (8.7%), Cl⋯H/H⋯Cl (8.2%) and C⋯H/H⋯C (7.7%) inter-actions.

Poly[[aqua-[μ2-1,3-bis-(pyridin-4-yl)urea-κ2N4:N4']bis-(μ3-5-tert-butyl-isophthalato-κ3O1:O1':O3)dizinc(II)] trihydrate], a double-strand coordination polymer.

In the title compound, {[Zn2(C12H12O4)2(C11H10N4O)(H2O)]·3H2O}n, monoperiodic coordination polymer double strands are held into the triperiodic crystal structure by means of N-H⋯O hydrogen-bonding patterns between the amide groups of the 1,3-di(pyridin-4-yl)urea ligands and unligated O atoms belonging to 5-tert-butyl-isophthalate ligands. One of the Zn atoms displays a tetra-hedral coordination environment, while the other Zn atom adopts a five-coordinate geometry inter-mediate between square pyramidal and trigonal bipyramidal. Additionally, O-H⋯O hydrogen-bonding patterns involving the water mol-ecules of crystallization serve as a structure-stabilizing element by aggregating the double-strand motifs.

Interpenetration Phenomena via Anion Template Effects in Fe(II) and Co(II) Coordination Networks with a Bis-(1,2,4-triazole) Ligand.

Seven new coordination networks, [Fe(tbbt)3](BF4)2 (1), [Co(tbbt)3](BF4)2 (2), [Fe(tbbt)3](ClO4)2 (3), [Co(tbbt)3](ClO4)2 (4), [Fe(NCS)2(tbbt)2] (5), [Co(NCS)2(tbbt)2] (6), and [Fe(H2O)2(tbbt)2]Br2·2H2O (7), were synthesized with the linker 1,1'-(trans-2-butene-1,4-diyl)bis-1,2,4-triazole (tbbt) and structurally investigated. The structure of complexes 1-4 is composed of three interpenetrating, symmetry-related 3D networks. Each individual 3D network forms a primitive, nearly cubic lattice (pcu) with BF4- or ClO4- anions present in the interstitial spaces. The structure of compounds 5 and 6 is composed of two-dimensional sql layers, which are parallel to each other in the AB stacking type. These layers are interpenetrated by one-dimensional chains, both having the same formula unit, [M(NCS)2(tbbt)2] (M = Fe, Co). The structure of compound 7 consists of parallel, two-dimensional sql layers in the ABCD stacking type. The interpenetration in 1-6 is not controlled by π-π-interactions between the triazole rings or C=C bonds, as could have been expected, but by (triazole)C-H⋯F4B, C-H⋯O4Cl, and C-H⋯SCN anion hydrogen bonds, which suggests a template effect of the respective non-coordinated or coordinated anion for the interpenetration. In 7, the (triazole)C-H⋯Br anion interactions are supplemented by O-H⋯O and O-H⋯Br hydrogen bonds involving the aqua ligand and crystal water molecules. It is evident that the coordinated and non-coordinated anions play an essential role in the formation of the networks and guide the interpenetration. All iron(II) coordination networks are colorless, off-white to yellow-orange, and have the metal ions in the high-spin state down to 77 K. Compound 5 stays in the high spin state even at temperatures down to 10 K.

13C NMR Chemical Shifts of Saccharides in the Solid State: A Density Functional Theory Study

In this work we present a systematic, theoretical investigation of the 13C NMR chemical shifts for several mono-, di- and trisaccharides in the solid state. The chemical shifts have been calculated using density functional theory (DFT) together with the gauge including the projector augmented wave (GIPAW) method as implemented in the CASTEP program. We studied the changes in the 13C NMR chemical shifts in particular due to the formation of one or two glycosidic linkages and due to crystal water. The largest changes, up to 14 ppm, are observed between the mono- and disaccharides and typically for the glycosidic linkage atoms, but not in all cases. An analysis of the bond angles at the glycosidic linkage and the observed changes in chemical shifts displays no direct correlation between them. Somewhat smaller changes in the range of 2 to 5 ppm are observed when single crystal water molecules are close to some of the atoms. Relating the changes in the chemical shifts of the carbon atoms closest to the crystal water to the distance between them does, however, not lead to a simple relation between them.

Poly[[bis-[μ4-3-(2-carboxyl-atophen-yl)propionato]{N-[2-(pyridine-3-amido)-eth-yl]nicotinamide}-dicopper(II)] penta-hydrate

In the title compound, {[Cu2(C10H8O4)2(C14H14N4O2)]·5H2O}n, the CuII cations are coordinated in a square-pyramidal fashion, with four 3-(2-carb-oxy-phen-yl)propionate (cpp) carboxyl-ate O-atom donors in the basal plane, along with an N-atom donor from a N-[2-(pyridin-3-yl-amino)-eth-yl]nicotinamide (pen) ligand in the apical position. [Cu2(cpp)2]n coordination polymer layer motifs with embedded {Cu2(OCO)4} paddlewheel clusters are thereby constructed. These layer motifs are connected into a three-dimensional [Cu2(cpp)2(pen)]n coordination polymer network by tethering pen ligands. Treating the {Cu2(OCO)4 paddelwheel clusters as 6-connected nodes reveals an underlying cross-pillared self-penetrated rob network with 48668 topology. The water mol-ecules of crystallization are held to the coordination polymer network by N-H⋯O and O-H⋯O hydrogen-bonding patterns.

Crystallization and characterization of K2NixCo1-x(SO4)2·6H2O mixed crystals for ultraviolet light filters and sensors

Mixed Tutton salts K2NixCo1-x(SO4)2·6H2O (KNICOSH) single crystals with x = 0, 0.20, 0.50, 0.80 and 1 were grown at 309 K using the slow evaporation of supersaturated aqueous solutions. X-ray diffraction analysis revealed the monoclinic structure, space group P21/a (C_2 h^5) and Z = 2, for each crystal obtained in this work. Thermal investigation showed several peaks that indicated the dehydration process, the exothermic reactions and melting points of K2NixCo1-x(SO4)2·6H2O crystals. The temperatures of these peaks increased with increasing x value, and it means that the crystals rich with Ni have higher thermal stability than those rich with Co. The infrared spectra of KNICOSH crystals showed three types of modes (internal modes of the sulfate ion, internal modes of water and librational modes of water). The wavenumber of internal modes of water increased systematically with increasing Ni content which indicate that the water molecules in KNISH crystal have hydrogen-bonding stronger than that of KCOSH crystal. The wavenumber of other infrared spectra modes changed unsystematically with increasing Ni content. K2Ni0.50Co0.50(SO4)2.6H2O crystal has the most absorption for the light at the visible range while at the ultraviolet region the absorption is low (high transmittance). This behavior enhanced its efficiency for using in ultraviolet light filters and sensors.

ДОСЛІДЖЕННЯ ВПЛИВУ РЕЖИМНИХ ФАКТОРІВ НА КІНЕТИКУ ПРОЦЕСУ ДЕГІДРАТАЦІЇ ЗАЛАЗІ (ІІ) СУЛЬФАТ ГЕПТАГІДРАТУ ФІЛЬТРАЦІЙНИМ МЕТОДОМ

The filtration method of gradual dehydration of Iron(II) sulfate heptahydrate hase been proposed. Based on the generalization of experimental data of hydrodynamics, the calculated dependence Euзовн=155∙Reзовн-0,55∙Hdч was obtained, which makes it possible to determine theoreticallypressure losses in the stationary layer of FeSO4·7H2O.According to the results of complex thermal analysis, the regularities of the gradual dehydration process of FeSO4·7H2O have been established in different temperature intervals. The temperature of 339K has been chosen, to implement the FeSO4∙7H2O dehydration process with the separation of the first three molecules of crystallization water, ensuring the preservation of the crystalline state of the product.The kinetics of moisture removal from FeSO4∙7H2Oat different heights of the material layer and velocities of heat agent movement have been investigated. Based on energy consumption calculations, the optimal parameters of the process were established: the height of the stationary layer Н = 60.10-3mand the fictitious velocities of the heat agent movement v0 =0,86 m/s.The filtration method of gradual dehydration of Iron(II) sulfate heptahydrate hase been proposed. Based on the generalization of experimental data of hydrodynamics, the calculated dependence Euзовн=155∙Reзовн-0,55∙Hdч was obtained, which makes it possible to determine theoreticallypressure losses in the stationary layer of FeSO4·7H2O.According to the results of complex thermal analysis, the regularities of the gradual dehydration process of FeSO4·7H2O have been established in different temperature intervals. The temperature of 339K has been chosen, to implement the FeSO4∙7H2O dehydration process with the separation of the first three molecules of crystallization water, ensuring the preservation of the crystalline state of the product.The kinetics of moisture removal from FeSO4∙7H2Oat different heights of the material layer and velocities of heat agent movement have been investigated. Based on energy consumption calculations, the optimal parameters of the process were established: the height of the stationary layer Н = 60.10-3mand the fictitious velocities of the heat agent movement v0 =0,86 m/s.

Synthesis, X-ray Structure of Two Hexa-Coordinated Ni(II) Complexes with s-Triazine Hydrazine Schiff Base Ligand

The hydrazine s-triazine ligand (E)-4,4’-(6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine-2,4-diyl)dimorpholine (DMPT) was used to synthesize two new Ni(II) complexes via a self-assembly technique. The two complexes were synthesized by a one-pot synthesis strategy and characterized by elemental analysis, FTIR and single-crystal X-ray diffraction analysis to be [Ni(DMPT)(H2O)3](NO3)2.3H2O (1) and [Ni(DMPT)(H2O)3](NO3)2.H2O (2). The structures of both complexes were very similar regarding the coordination sphere and counter anions, but differ only in the number of the crystal water molecules. In the case of complex 1, there are three water molecules instead of one H2O molecule as in complex 2. In the two complexes, the DMPT ligand acts as a neutral tridentate NNN-chelate via three Ni–N coordination interactions. The coordination sphere of the Ni(II) ion is completed by three water molecules. As a result, the two complexes exhibit distorted octahedral geometry. The Hirshfeld surfaces around each entity in both complexes have been computed. Subsequently, their corresponding intermolecular interactions were quantified separately. Because the number of crystal water molecules is different in both complexes, their monomeric units are connected differently in their crystal structures where the crystal water molecules act as both hydrogen bond donor and acceptor. The polar O…H interactions are the most dominant in all entities of both complexes. As a result, strong O…H interactions are the driving force in the crystal packing of both complexes, and this is attributed to the presence of the nitrate anions and water molecules. The antimicrobial activity of the free ligand and complex 1 were determined against two selected fungal species, Gram-negative and Gram-positive bacterial strains. The free ligand was found to be inactive against all microbial species. On the other hand, the Ni(II) complex 1 was found active against the Gram-positive bacterial species Bacillus subtilis and also the Gram-negative bacterial species Escherichia coli. The respective inhibition zone diameter of the Ni(II) complex was 12 and 11 mm, respectively.

Crowding-out strategy to enhance energetics of 3-nitro-1,2,4-triazol-5-one based E-MOFs at the molecular level through adjusting pH

Based on the combination of coordination chemistry and the noncovalent interactions, the crowding-out concept is put forward to fundamentally solve the problem that the structural H2O in E-MOFs results in a decreased stability, density and heats of detonation. In this paper, “filling” the 4,4′-azobis(1,2,4-triazole) (ATRZ) molecules into the structure of NTO (3-nitro-1,2,4-triazol-5-one) E-MOFs, the coordination and crystal water molecules were successfully extruded to gain anhydrous [Cu(NTO)2(ATRZ)] (a) / [Zn(NTO)2(ATRZ)] (c) and hypohydrous [Co(NTO)2(ATRZ)(H2O)2]·ATRZ (b) by adjusting pH at room temperature and pressure, which is friendly for energetic materials. With the addition of ATRZ (high HOF) and the departure of water, the ΔfHmθ of them are becoming higher. The heat of detonation is increased by 1.33, 2.39 and 0.74 times respectively and the calculated detonation velocity of three compounds is enhanced by about 1000 m s−1 contrasted to the corresponding hydrates. The removal of water molecules did not result in a high sensitivity. More importantly, as potential catalysts for AP-based solid propellants, a and c still showed excellent catalysis for the thermal decomposition of AP (ammonium perchlorate) after modification. In this study, it took a whole new idea to radically solve the difficulties in the area of E-MOFs by a simple and original way, and this is a significant innovation for the safety of energetic material.