Metal formate hydrazines

Metal formate hydrazines M(HCOO)2(N2H4)2 (where M = Mn, Co, Ni, Zn, and Cd) are prepared by the addition of excess hydrazine hydrate to the corresponding metal formate hydrates [10]. The reaction is instantaneous with the evolution of heat ... 

Metal formate hydrazines exhibit autocatalytic combustion behavior when heated rapidly. Although TG/DTA shows endothermic decomposition in the beginning, combustion of these complexes is exothermic, since both hydrazine and formate undergo oxidation simultaneously. 

Ravindranathan, P. and Patil, K.C. (1983) Thermal reactivity of metal formate hydrazinates. Thermochimica Acta, 71, 53-57. 

Hydrazine hydrate dissolves many inorganic salts readily most of these salts recrystallize from the solution to form stable solvates or adducts that do not dissolve further. Additionally, the reaction of hydrazine with mineral adds/organic acids also leads to the formation of crystalline solids. These colored compounds are mostly single crystals although polycrystalline products can also be obtained. In metal complexes, hydrazine appears as either singly or doubly protonated cation and plays an important role in forming various hydrogen bond networks in their derivatives. For this reason, it is of interest to determine their crystal structures. 

Interestingly, in all these synthesis methods, although one starts with the thiocyanate salt, with hydrazine as one of the ligands, the metal chelates to the N atom of the anion to form complexes of the rearranged isothiocyanate type. This formation of metal isothiocyanate hydrazines is confirmed by chemical analysis and infrared spectra (Table 3.1). 

The features of the thermal analysis data show that metal acetate hydrazines decompose exothermically, in three steps, to their respective metal oxides. Manganese, cobalt, zinc, and cadmium complexes decompose through the formation of their corresponding metal acetates, while the nickel complex decomposes through a mixture of nickel metal and nickel acetate (Figure 3.5). The zinc complex however, loses both hydrazine molecules in a single step, while Mn, Co, and Cd complexes lose hydrazine in two steps. The metal oxide formation temperatures from the decomposition of metal acetate hydrazine complexes occur at 275-385 °C. These are lower than those reported for metal acetate hydrates, which occur at 350-400 °C. 

As the structure of metal acetate hydrazine complexes appears to be isomorphous, the formation of mixed metal hydrazines takes place easily. This is further confirmed by the identical infrared spectra of Nii/3Co2/3(CH3COO)2(N2H4)2 with the nickel and cobalt acetate hydrazine complexes (Figure 3.6). 

Patil, K.C., Gajapathy, D., and Pai Verneker, V.R. (1982) Low temperature ferrite formation using metal oxalate hydrazinate precursor. Materials Research Bulletin, 17, 29-32. 

Table 4.7 gives thermal decomposition data of N2H5M(N2H3COO)3-H2O. The iron complex shows a single step in TG-DTG and two exotherms in DTA, while both cobalt and nickel complexes show two-step decomposition in TG-DTG and two exotherms in DTA. The observed weight loss after the first step corresponds to the formation of metal oxalate hydrazine... 

The reduction of molybdate salts in acidic solutions leads to the formation of the molybdenum blues (9). Reductants include dithionite, staimous ion, hydrazine, and ascorbate. The molybdenum blues are mixed-valence compounds where the blue color presumably arises from the intervalence Mo(V) — Mo(VI) electronic transition. These can be viewed as intermediate members of the class of mixed oxy hydroxides the end members of which are Mo(VI)02 and Mo(V)0(OH)2 [27845-91-6]. MoO and Mo(VI) solutions have been used as effective detectors of reductants because formation of the blue color can be monitored spectrophotometrically. The nonprotonic oxides of average oxidation state between V and VI are the molybdenum bronzes, known for their metallic luster and used in the formulation of bronze paints (see Paint). 

Palladium catalysts have been prepared by fusion of palladium chloride in sodium nitrate to give palladium oxide by reduction of palladium salts by alkaline formaldehyde or sodium formate, by hydrazine and by the reduction of palladium salts with hydrogen.The metal has been prepared in the form of palladium black, and in colloidal form in water containing a protective material, as well as upon supports. The supports commonly used are asbestos, barium carbonate, ... 

The formation of semiconductor nanoparticles and related stmctures exhibiting quantum confinement within LB films has been pmsued vigorously. In 1986, the use of the metal ions in LB films as reactants for the synthesis of nanoscale phases of materials was described [167]. Silver particles, 1-2 mn in size, were produced by the treatment of silver be-henate LB films with hydrazine vapor. The reaction of LB films of metal salts (Cd, Ag, Cu, Zn, Ni, and Pb ) of behenic acid with H2S was mentioned. The use of HCl, HBr, or HI was noted as a route to metal halide particles. In 1988, nanoparticles of CdS in the Q-state size range (below 5 mn) were prepared inside LB films of cadmium arachi-... 

Whether nitrogen is in the reduced form (ammonia, ammonium salts, hydrazine) or the oxidised form (nitrites, nitrates), sodium gives rise to dangerous interactions. With the first set of compounds metalation occurs with formation of unstable or highly reducing compounds, whilst, with the second, redox reactions occur. 

Hydrazine and its Derivatives, Schmidt, F. W., New York, Wiley, 1984, 75 Use of excess calcium metal, or its solution in ammonia (presumable calcamide) to dry hydrazine leads to formation of calcium hydrazide and explosion. Calcium hydride and carbide are, apparently, safe drying agents... 

Interaction of anhydrous hydrazine and titanium isopropoxide is explosive at 130° C in absence of solvent. Evaporation of solvent ether from the reaction product of tetrakis(dimethylamino)titanium and anhydrous hydrazine caused an explosion, attributed to formation and ignition of dimethylamine. /V-Metal derivatives may also have been formed. 

In contrast with formation of three types of bpz-substituted RU3 cluster species, reactions of 2 with pyq induced isolation of monomer 45 and trimer 46 containing 6>rf/ 6>-metallated pyq depending on the reaction conditions [30]. Reduction of the 3+ trimeric complex 46 by addition of aqueous hydrazine gave neutral species 46a. Oxidation of 46a by addition of two equivalents of ferrocenium hexaflu-orophosphate afforded 2+ intercluster heterovalent complex46b containing two Ru30(0Ac)6(py)2II,III,m and one Ru30(OAc)5(py)2II,m,n moieties. 

Apart from complex formation involving metal ions (as discussed in Chapter 4), crown ethers have been shown to associate with a variety of both charged and uncharged guest molecules. Typical guests include ammonium salts, the guanidinium ion, diazonium salts, water, alcohols, amines, molecular halogens, substituted hydrazines, p-toluene sulfonic acid, phenols, thiols and nitriles. 

In earlier studies the in vitro transition metal-catalyzed oxidation of proteins and the interaction of proteins with free radicals have been studied. In 1983, Levine [1] showed that the oxidative inactivation of enzymes and the oxidative modification of proteins resulted in the formation of protein carbonyl derivatives. These derivatives easily react with dinitrophenyl-hydrazine (DNPH) to form protein hydrazones, which were used for the detection of protein carbonyl content. Using this method and spin-trapping with PBN, it has been demonstrated [2,3] that protein oxidation and inactivation of glutamine synthetase (a key enzyme in the regulation of amino acid metabolism and the brain L-glutamate and y-aminobutyric acid levels) were sharply enhanced during ischemia- and reperfusion-induced injury in gerbil brain. 

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