Hydrazinium Cation Research Articles

Crystal structures and thermal analyses of three new high-energy hydrazinium hydro-closo-borates

New hydrazinium hydro-closo-borates with [BnHn]2– anions (n = 10 and 12) were obtained by direct reaction of the free acids (H3O)2[BnHn] with hydrazinium hydrate (N2H4 · x H2O) in aqueous solution. The three new compounds (N2H5)2[B10H10], (N2H5)2[B10H10] · 2 N2H4 and (N2H5)2[B12H12] · 2 N2H4 crystallize in the space groups P21/c, C2/c and P1‾, respectively. They contain up to 11 wt-% hydrogen. Two main kinds of bonding were observed in all crystal structures, classical hydrogen bonds (Nδ––Hδ+⋯Nδ–) and dihydrogen bonding between the negatively polarized hydrogen of the boron clusters and positively polarized hydrogen in hydrazinium cations (Bδ+–Hδ–⋯Hδ+–Nδ–). Thermal decomposition analyses of these compounds show that they absorb energy first, and then release a huge amount of energy upon decomposition and collapse of the structure. Due to the differently polarized hydrogen atoms in these compounds, hydrogen molecules (H2) are generated during the decomposition, which can be used as hydrogen fuel.

Structural and Multi-functional properties of isoelectronic guanyl hydrazinium picolinic derivatives exhibit centric and non-centric space group

The equimolar reaction mixture of isoelectronic picolinic acid N-oxide (PAHNO) and/or 3-hydroxy picolinic acid (3-HPAH) with guanyl hydrazine bicarbonate (AgunH.HCO3) in aqueous medium at room temperature produce 1:1 salt. Irrespective of the molar ratios (1; 1, 1:2 & 2:1) and reaction conditions maintained, invariably gives the same product in the form of polycrystalline nature except 1:1 ratio which yields a single crystal. The isoelectronic salts were characterized by spectroscopic, PXRD, thermal study and single crystal X-ray diffraction techniques. In general, most of the salts were crystallized in a centric space group rather than a non-centric, the prevailing factors are nature of the organic species and reaction conditions like pH, pKa, solvent effects, temperature and molar ratio etc,. Surprisingly, in the present case, the isoelectric salt of [AgunH]+[PANO]- crystalized in centric (P21/n), where in case of [AgunH]+[3-HPA]- crystalized in non-centric (Pca21) space group even though in the same reaction conditions. This may be due to the presence of the 3rd position of hydroxyl group and non-covalent interactions in [AgunH]+[3-HPA]- that facilitate non-centric space group. Both salts are stabilized by the variety of hydrogen bond features leading to intra- and intermolecular N-H⋯O, N-H⋯N, and C-H⋯N hydrogen bonds and π-π stacking interactions along with homo- and hetero ring motifs [two R22 (8), R11 (6), and two R22 (9)]. These interactions render them an appropriate acid-base ion pair for the formation of sturdy hydrogen-bonded supramolecular synthons. Thermal studies on these salts reveal that the thermal degradation occurs via melting followed by complete loss of organic species. The solid-state emission spectra of free acids and its salts were recorded and compared. The materials exhibit a prominent luminescent character towards red shift than the starting compounds. Further, these materials show enhanced secondary antioxidant and antimicrobial activities, this is due to the crucial role of hydrazine species in guanyl hydrazinium cation.

Hydrazinium cation mixed FAPbI3-based perovskite with 1D/3D hybrid dimension structure for efficient and stable solar cells

FAPbI3 has been greatly developed in Perovskite solar cells (PSCs) profiting from their narrow bandgap, high panchromatic absorption and long carrier diffusion length. Unfortunately, the phase instability of FAPbI3-based perovskite restricts its further development in PSCs. Here, hydrazinium cation (HA+: NH2NH3+) is incorporated into FAPbI3-based perovskite to obtain novel 1D/3D hybrid dimension structure with stable α-FAPbI3 for the first time. The strong hydrogen bonding of HA+ increases the crystallinity and grain size of perovskite. Furthermore, SEM and TEM reveal that the new HA based 1D-phase (1D-HA-phase) exists like “rivet” passivating among the grain boundary of 3D perovskite, forming 1D/3D hybrid dimension structure contributing to the stability of FAPbI3-based perovskite. Confocal fluorescence microscopy, time-resolved photoluminescence spectroscopy and Kelvin probe force microscope measurements reveal that the trap state can be effectively restrained and the non-radiative recombination is largely suppressed in HA+ mixed FAPbI3-based perovskite film with 1D-HA-phase. Finally, stable α-FAPbI3-based perovskite and its film with high crystallinity, smooth surface morphology, excellent photovoltaic performance and few defects are obtained. PSC using (FAMACs)0.85HA0.15 perovskite achieves a power conversion efficiency of 21.20% which can retain 90% at room temperature in ambient environment for 2520 h.

From van der Waals interactions to structures and properties of 3,[formula omitted]-dinitro-5,[formula omitted]-bis-1,2,4-triazole-1,[formula omitted]-diolate based energetic materials

As a continuation for the search of precise correlation between performance and sensitivity of high energy density materials (Phys. Chem. Chem. Phys. 2018, 20, 29693), we present structure analysis and quantum mechanical calculations for similar energetic ionic salts (EIS) based on 3,3′-dinitro-5,5′-bis-1,2,4-triazole-1,1-diolate anion with ammonium (DA-DNBTO) and hydrazinium (DH-DNBTO) cations. The geometry optimization demonstrate the importance of van der Waals correction when studying the structure and properties of EIS, and highlights the significance of DFT-D2 method proposed by Grimme in reproducing the experimental crystal structures of energetic salts. The IR spectrum of DA-DNBTO contains more number of intense peaks in the high frequency range (above 2850 cm−1) compared to DH-DNBTO. Especially, the electronic band gap of DNBTO salts obtained using the HSE06 hybrid functional are reduced to 50% when compared with that of BTO based energetic salts due to NO2 group attached to the DNBTO anion. Besides, we find that the O...O contacts that generally exist in most of the energetic materials do not show much impact in both the studied energetic salts. The strong intermolecular interactions of DA-DNBTO represents its inferiority in molecular stability, which is in good agreement with the experimentally measured impact sensitivity (>40 J) and friction sensitivity (360 N) values and also explains why it has highest stability compared to DH-DNBTO. Our calculations re-verifies the importance of intermolecular hydrogen bonding in the construction of high performance and low sensitive energetic materials.

Spectral, Thermal, Crystal Structure, Hirshfeld Surface Analyses and Biological Activities of New Hydrazinium Dipicolinato Copper(II) Tetrahydrate

A new copper complex of pyridine-2,6-dicarboxylate containing hydrazinium cation, formulated as (N2H5)2[Cu(PDC)2]·4H2O (PDC = pyridine-2,6-dicarboxylate) has been synthesized from copper(II) nitrate, hydrazine hydrate and pyridine-2,6-dicarboxylic acid as a single crystal and characterized by elemental analysis and spectroscopic (IR and UV-visible), thermal (TG/DTG), single crystal X-ray diffraction and biological studies. A six-coordinate complex with a distorted octahedral geometry around Cu(II) ion is proposed and confirmed by X-ray single crystal method. The structure reveals that two pyridine-2,6-dicarboxylate species acting as tridentate ligands and hydrazinium cation present as a counter ion along with non-coordinated four water molecules. The structural units of copper(II) is mutually held by the hydrogen bonds and π···π and C–O···π interactions. The copper(II) complex is connected to one another via O–H···O hydrogen bonds, forming water clusters, which plays an important role in the stabilization of the crystal structure. In the water clusters, the water molecules are trapped by the cooperative association of coordination interactions as well as hydrogen bonds. Both cation and anion interactions and crystal from various types of intermolecular contacts and their importance were explored using Hirshfeld surface analysis. This indicates that O···H/H···O interactions are the superior interactions conforming excessive H-bond in the molecular structure. The interaction of copper(II) complex with calf thymus DNA (CT-DNA) was investigated by electronic absorption spectroscopic technique. The electronic evidence strongly shows that the compound interacts with calf thymus through intercalation with a binding constant of Kb = 5.7 × 104 M–1.

New agent for nitric oxide (NO) chemotherapy: Synthesis and properties of DNIC with hydrazinium cation in solid phase and solutions

New method for the synthesis of the mononuclear anionic iron dinitrosyl complexes (DNICs) as prospective agents for nitric oxide (NO) chemotherapy of oncological diseases has been developed. Mononuclear anionic DNIC of the composition (N2H5)+[Fe(SR)2(NO)2]- with R = 5-nitropyridinyl (I) has been synthesized by the reaction of aqueous solutions of Na2[Fе(S2O3)2(NO)2] and N2H5[SС5H3N2O2] salts. The latter one was synthesized by the reduction of bis-(5-nitro-pyridin-2-yl) disulfide with hydrazine hydrate in ethanol at T = 25 °C. Physical-chemical properties of the synthesized complex were studied by X-ray, SEM, IR-, EPR, Mössbauer spectroscopy and SQUID magnetometry in combination with DFT quantum-chemical calculation of molecular structure and spectroscopic properties. Complex I was found to generate NO in proton media without additional activation. The cytotoxicity of I to human tumor cells of various geneses, viz. ovarian cancer SKOV3, colon cancer LS174T and non-small cell lung cancer A549 was discovered for the first time.

A New Perspective on the Role of A‐Site Cations in Perovskite Solar Cells

AbstractAs the race toward higher efficiency for inorganic/organic hybrid perovskite solar cells (PSCs) is becoming highly competitive, a design scheme to maximize carrier transport toward higher power efficiency has been urgently demanded. In this study, a hidden role of A‐site cations of PSCs in carrier transport, which has been largely neglected is unraveled, i.e., tuning the Fröhlich electron–phonon (e–ph) coupling of longitudinal optical (LO) phonon by A‐site cations. The key for steering Fröhlich polaron is to control the interaction strength and the number of proton (or lithium) coordination to halide ions. The coordination to I− alleviates electron–phonon scattering by either decreasing the Born effective charge or absorbing the LO motion of I. This novel principle discloses low electron–phonon coupling in several promising organic cations including hydroxyl–ammonium cation (NH3OH+), hydrazinium cation (NH3NH2+) and possibly Li+ solvating methylamine (Li+∙∙∙NH2CH3), on a par with methyl–ammonium cations. A new perspective on the role of A‐site cations could help in improving power efficiency and accelerating the application of PSCs.

Crystal Structure of Hydrazinium Iodide by Neutron Diffraction

The structure of hydrazinium iodide, [H5N2]+·I−, at 100 K has monoclinic (P21/n) symmetry from single crystal neutron diffraction with a = 7.4599(7) A, b = 5.3185(6) A, c = 10.1628(11) A, β = 103.150(10)°, V = 392.64(7) A3, Z = 4. The refinement converged to R = 0.0575, wR 2 = 0.1602, S = 1.022. Data for the crystal structure was collected on the SNS TOPAZ single-crystal time-of-flight Laue diffractometer. The compound has a one-dimensional structure which displays N–H···N hydrogen bonding. Accurate intra- and intermolecular N–H distances have been determined. Extended hydrogen bonds among the hydrazinium cations in the crystal structure of N 2 H 5 I.

The crystal structure of (C2H9N2)2[Zn3(HPO3)4], a three-dimensional zincophosphite framework containing 16-membered rings templated by the unsymmetrical dimethyl hydrazinium cation.

The solution-mediated synthesis and crystal structure of 1,1-di-methyl-hydrazinium tetra-phoshonoatotrizincate, (C2H9N2)2[Zn3(HPO3)4], are described. The anionic [Zn3(HPO3)4]2- framework is built up from alternating ZnO4 tetra-hedra and HPO3 pseudo-pyramids to generate a three-dimensional 4,3-net encapsulating the C2H9N2+ cations. The organic cations, which are protonated at their central N atoms, occupy pores delineated by large 16-membered polyhedral rings and inter-act with the framework by way of N-H⋯O hydrogen bonds and possible C-H⋯O inter-actions. One of the zinc ions lies on a crystallographic twofold rotation axis and all the other atoms lie on general positions. The crystal studied was found to be rotationally twinned about the [001] axis in reciprocal space in a 0.585 (5):0.415 (5) ratio.

The Role of Adsorption in the Electrocatalysis of Hydrazine on Platinum Electrodes

AbstractHydrazine oxidation on platinum single‐crystal electrodes has been studied in acidic solution containing different electrolytes. It will be shown that the hydrazinium cation is adsorbed on platinum through an anodic reaction. Moreover, in the presence of chloride, this adsorption process is favored owing to the formation of an ionic pair with adsorbed chloride. In spite of the enhanced adsorption of hydrazine species in the presence of chloride, higher overpotentials are measured in these media, which reveals that the oxidation of hydrazine not only requires adsorption, but also that the adsorption mode of the species facilitates the formation of the transition state to yield the final product.

Perovskite-Like Polar Lanthanide Formate Frameworks of [NH2NH3][Ln(HCOO)4] (Ln = Tb-Lu and Y): Synthesis, Structures, Magnetism, and Anisotropic Thermal Expansion.

A series of isostructural hydrazinium lanthanide (Ln) formate framework compounds of [NH2NH3][Ln(HCOO)4] for Ln3+ ions from Tb3+ to Lu3+ and Y3+ have been successfully prepared by utilizing NH2NH3+. The compounds crystallize in orthorhombic polar space group Pca21, with cell parameters at 180 K of a = 18.2526(7)-18.1048(5) Å, b = 6.5815(2)-6.5261(2) Å, c = 7.6362(3)-7.5044(2) Å, and V = 917.33(6)-886.67(4) Å3, showing the effect of lanthanide contraction. The compounds possess polar perovskite-like structures incorporating the hydrazinium cations in the cavities of the NaCl-like framework, in which the Ln3+ ions in a bicapped trigonal prism are connected by anti-anti and syn-anti formate groups. The N-H···Oformate hydrogen-bonding interactions are between the hydrazinium cations and the anionic framework. One anti-anti formate group is frustrated by the competitive N-H···Oformate hydrogen-bonding interactions. It thus twists or flips upon warming, resulting in large anisotropic thermal expansion and negative thermal expansion below 180 K. A comparison with the transition metal and magnesium analogues revealed that the structural compactness, tighter binding of the hydrazinium cation by the framework, and symmetrically better match between the framework and ammonium cation for Ln compounds could inhibit the occurrence of phase transition in the series. The IR spectroscopic, thermal, and magnetic properties are investigated.

Synthesis, crystal structure, spectroscopic and thermal analysis of hydrazinium hydrogen-3,5-pyrazoledicarboxylate monohydrate

A new hydrazinium(+1) salt of 3,5-pyrazoledicarboxylic acid (H2Pzdca) of formula, (N2H5)HPzdca·H2O (HPzdca is a hydrogen-3,5-pyrazoledicarboxylate anion), was prepared and characterized using elemental analysis, FT-IR spectroscopy, TG-DTA, and single-crystal X-ray diffraction analysis. The salt crystallized in the space group P21/c. The monoclinic unit cell of the title compound, N2H5 +·C5H4N2O4 −·H2O, is a molecular salt consisting of one mono-protonated hydrazine cation [hydrazinium(+1) cation], one singly deprotonated hydrogen-3,5-pyrazoledicarboxylate anion, and one solvent water molecule. The overall structure is a 3-D supramolecular network formed through extensive O–H…O and N–H…O hydrogen-bonding interactions. Although the H2Pzdca monohydrate exhibited a two-step (110 and 298 °C) decomposition, its salt had multiple-step decompositions. The free acid underwent only endothermic decomposition, while its hydrazinium salt underwent an endothermic decomposition, followed by sharp exothermic degradation to form a black residue as the end product.

Hydrazinium-loaded perovskite solar cells with enhanced performance and stability

In this study, we show that partial substitution of methylammonium (MA) with hydrazinium (HA) cations in MAPbI3 improves both the photovoltaic performance and stability of the hybrid perovskite solar cells.

Stability of Hydrazine, Morpholine and Ethanolamine at 275 °C and In Situ Measurement of Redox and Acid–Base Properties

The hydrothermal reduction of nitrogen is important in several fields. Hydrazine and amines are injected in the secondary circuit of the pressurized water reactors (PWR) nuclear plants to minimize materials corrosion. Amines are also possible reactants in the nitrogen chemistry of submarine hydrothermal vents. To better evaluate the chemical properties of N-bearing hydrothermal solutions, experiments have been carried out at 275 °C using a hydrothermal reactor equipped for a potentiometric monitoring, allowing in situ pH and Eh measurements. The thermal decomposition of hydrazine in simulated feed waters steam generators of PWR plants was monitored and appeared to be catalyzed by the surface of the titanium vessel or by magnetite particles, present as a model of the usual corrosion products. Rates are also dependent on pH or, keeping in mind that it is a catalyzed reaction, on the increasing proportion of N2H4 relative to N2H 5 + , the hydrazinium cation being less sorbed under acidic conditions. Ethanolamine appears to be stable for over a month while morpholine is decomposed in few days in contact with magnetite. The in situ pH measurements are consistent with theoretical predictions using acidity constants of morpholine and ethanolamine from the limited literature data. The redox potential imposed by hydrazine was measured and was between −0.45 V (pHT = 5) and −0.65 V (pHT = 7) provided that the concentration of hydrazine exceeds the threshold concentration of 20–50 μg·kg−1. Above this concentration, the potential was poorly dependent on the hydrazine concentration. The observed pH–Eh relationship reflects proton production during the oxidation of N2H4 to N2. From the Eh values, a standard potential of −1.1 V at 275 °C has been calculated for this reaction.

Hydrolysis of hydrazido-oxalic acid leading to the formation of hydrazinium cadmium hydrazido-oxalate/uranium oxalate species with a polymeric structure

A series of new metal hydrazido-oxalates with the formula [M(Hox)2(H2O)2]·nH2O, where M=Co (1), Ni (2) and Zn (3); Hox=hydazido-oxalate; n=0 (Co), 1 (Ni) and 5 (Zn), as well as (N2H6)0.5[Cd(Hox)2]NO3 (4) and the hydrazinium uranyl oxalate (N2H6)[(UO2)2(C2O4)3]·2H2O (5) were synthesized. Among the five synthesized compounds, the structures of 1, 4 and 5 were characterized by single crystal X-ray diffraction. The hydrazinium cation and oxalate anions generated in the synthesis were derived from hydrazido-oxalic acid, which is present in compounds 4 and 5. The structure of compound 1 consists of an octahedral coordination around cobalt, arising from two chelating (N,O) acid hydrazide ligands, coordinating through the carbonyl oxygen and hydrazinic nitrogen atoms in a cis-fashion, and two monodentate water molecules. It is interesting to note that the anionic carboxylate moieties are not involved in the coordination. Unlike cobalt, the anhydrous cadmium compound (4) consists of a hydrazinium (+2) cation, nitrate anion and a neutral cadmium hydrazido-oxalate complex. In this complex, the Cd(II) site has a coordination number of eight, comprising of six oxygen atoms and two nitrogen atoms with four adjacent hydrazido-oxalates. Thus, the polyhedral arrangement around the cadmium atoms is connected by hydrazido-oxalate groups to form a 2D framework [Cd(Hox)2], with tunnels and a square grid cross-section in two directions which form a cavity at their intersection. The structure of compound 5 consists of a two-dimensional network of uranyl and oxalate ions that form hexagonal rings. Specifically, the oxalate ions are tetradentate, each bridging two uranyl ions which are coordinated by three oxalate groups, and this results in a distorted hexagonal bipyramidal environment for the uranium atoms.

Crystal structures of tetravalent uranium fluorides obtained in the presence of hydrazine from uranyl source

Four new tetravalent uranium fluorides have been obtained by using hydrothermal route from a hexavalent uranium precursor (UO2(NO3)2·6H2O or UO2(SO4)·4H2O) in the presence of hydrazine and HF in water. The major phase is the hydrated uranium fluoride U3F12(H2O) (1) and in some conditions, four other phases are formed in mixture with the latter. Both compounds 2 and 3 exhibit layered structures with intercalated hydrazinium cations. UF5·H3N-NH2 (2) consists of double uranium fluoride sheets with nine-fold coordinated uranium (UF9, tricapped trigonal prism). It is related to the anionic archetype [UF5]−·X+ or [U2F10]2−·Y2+ (depending of the charge of the counter-cations) previously reported in literature. U3F4(SO4)6·2NH4·H3N-NH3 (3) contains trinuclear μ3-fluoro-centered uranium (UO6F3, tricapped trigonal prism) core linked to each other via the sulfate groups in order to form infinite sheets intercalated by ammonium and diprotonated hydrazinium cationic species. It is a new type of uranium arrangement for tetravalent uranium sulfates. The phases NaU2F9 (4) and NaU6F25 (5) appeared when sodium sulfate is added to the reaction medium. Crystal structure of 4 can be viewed from the connection of double uranium fluorides layers of nine-fold coordinated uranium (UF9) centers, similar to that observed in the compound 2. Due to the small size of sodium cation, the resulting [UF5]− sheets are connected to each other via the remaining non-bonded fluoride anions in order to form a three-dimensional network with channels encapsulating the alkali atoms. The structure of NaU6F25 (5) corresponds to the stacking of double layers of 6-membered ring sub-net of UF9 units, resulting in the formation of elongated cavities in which sodium atoms are located.

Synthesis, Structure, Antioxidant, and Antiviral Studies on N2H5[Ln(edta)(H2O)3].5H2O (Ln = Pr, Nd, and Sm)

Single crystals of N2H5[Ln(edta)(H2O)3].5H2O (Ln = Pr, Nd and Sm) have been prepared and the molecular structures of these crystals were determined by X-ray single crystal study. The X-ray powder diffraction patterns of the three complexes reveal that they are isomorphous. These complexes are nine coordinated with a hexadentate edta4− ion and three coordinated water molecules. However, the remaining five more water molecules present as lattice water. Hydrazinium cation, though capable of coordination with the metal ion, in the present case present outside the coordination sphere as primary valency. The Ln(III)N2O4O′3 parts in the complex anions have the same structures in all the three complexes. The crystals of Pr(III), Nd(III), and Sm(III) complexes belong to the orthorhombic crystal system and Fdd2 space group. The crystal data are as follows: Pr(III): a = 19.6712(5) Å, b = 35.6939(9) Å, c = 12.3079(4) Å, α = β = γ = 90°, V = 8641.9(4) Å3, R = 0.0255, and Rw = 0.0728 for I>2σ (I) and 10119 reflections. Nd(III): a = 19.6414(3) Å, b = 35.6177(5) Å, c = 12.3212(2) Å, α = β = γ = 90°, V = 8619.7(2) Å3, R = 0.0251, and Rw = 0.0693 for I > 2σ (I) and 7378 reflections. Sm(III): a = 19.5814(3) Å, b = 35.4617(7) Å, c = 12.2931(2) Å, α = β = γ = 90°, V = 8536.2(3) Å3, R = 0.0233, and Rw = 0.0641 for I > 2σ (I) and 6766 reflections. These complexes show promising antioxidant activity as expected for lanthanide(III) ions with unpaired electrons. The antiviral screening also shows enhanced activities of these complexes than the respective non-hydrazinium and ammonium chelates. The crystals of the complexes in purest form were powdered and subjected to constant temperature degradation at 600°C to yield pure fine powders of the respective oxides. The microstructures of the oxides were studied by scanning electron microscope photographs.

Poly[hydrazin-1-ium [diaquabis(μ4-pyridazine-3,6-dicarboxylato)trilithate] monohydrate

The structure of the title compound, {(N2H5)[Li3(C6H2N2O4)2(H2O)2]·H2O}n, is composed of mol­ecular dimers, each built up of two symmetry-related LiI ions with distorted trigonal–bipyramidal coordinations bridged by two deprotonated ligand mol­ecules via their N,O-bonding sites. Doubly solvated LiI ions with a distorted tetra­hedral geometry link adjacent dimers, forming a polymer generated by bridging bidentate carboxyl­ato O atoms to LiI ions in adjacent dimers, forming anionic layers parallel to the ac plane with monoprotonated hydrazinium cations and crystal water mol­ecules positioned between them. The layers are held together by an extended system of hydrogen bonds in which the hydrazinium cations and coordinated and crystal water mol­ecules act as donors and carboxyl­ate O atoms act as acceptors.

Molecular Structure, Thermal Reactivity, Spectral Properties and Biological Activities of Hydrazinium Metal(II) and Metal(III) Ethylenediaminetetraacetate Hydrates

Hydrazinium metal(II) ethylenediaminetetraacetate dihydrates, [N2H5M(Hedta)](H2O)2 where M = Fe(II), Co(II) or Ni(II) and hydrazinium metal(III) ethylenediaminetetraacetate monohydrates, N2H5[M(edta)(H2O)] where M = Cr(III), Fe(III) or Co(III) have been prepared and characterized by chemical analyses, magnetic moment, electronic and infrared spectra and X-ray powder diffraction studies. The X-ray single crystal structures of Ni(II) and Fe(III) complexes were determined. The nickel complex is octahedral with pentadentate Hedta3− ion and the sixth site is occupied by hydrazinium cation. However, Fe(III) complex is found to be seven coordinated with a hexadentate edta4− anion and a water molecule which occupying the seventh site of the coordination sphere. Both the sets of complexes show enhanced antioxidant activity than their non-hydrazinium counterparts. However, the metal(III) complexes show better antioxidant activity than the corresponding metal(II) complexes. The metal(II) and metal(III) complexes have been also subjected to antiviral screening. These results show that these complexes are active against HSV-1 and HSV-2 viruses. Hydrazinium complexes of metal(II) and metal(III) ethylenediaminetetraacetate hydrates have been synthesized and characterized by analytical, spectral, thermal and X-ray studies. The crystal structures of Ni(II) and Fe(III) complexes have been described. The antioxidant and antiviral studies have also been presented.

The acid adducts hydrazinium 2-hydroxybenzoate–2-hydroxybenzoic acid (1/1) and hydrazinium 3-hydroxy-2-naphthoate–3-hydroxy-2-naphthoic acid (1/1)

The title molecular salts, N(2)H(5)(+)·C(7)H(5)O(3)(-)·C(7)H(6)O(3) and N(2)H(5)(+)·C(11)H(7)O(3)(-)·C(11)H(8)O(3), are acid adducts containing a hydrazinium cation, one molecule of a deprotonated acid and one molecule of a neutral acid. The two compounds contain essentially identical hydrogen-bond networks between the hydrazinium cation and the acid molecules, which define closely comparable two-dimensional layers in the structures. The planes of the aromatic rings within both structures are approximately parallel and the layers are stacked with comparable intermolecular interactions.