Nitrates complex

These exhibit high coordination numbers. Double nitrates Mg3Ln2(N03)i2.24H20, which contain [Ln(N03)6] ions, are important historically as they were once used for the separation of the lanthanides by fractional crystallization. Use of counter-ions like Ph4P+ and Me4N+ allow isolation of the 10-coordinate [Ln(N03)5] ions. 

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Uranium Purification. Subsequent uranium cycles provide additional separation from residual plutonium and fission products, particularly zirconium— niobium and mthenium (30). This is accompHshed by repeating the extraction/stripping cycle. Decontamination factors greater than 10 at losses of less than 0.1 wt % are routinely attainable. However, mthenium can exist in several valence states simultaneously and can form several nitrosyl—nitrate complexes, some for which are extracted readily by TBP. Under certain conditions, the nitrates of zirconium and niobium form soluble compounds or hydrous coUoids that compHcate the Hquid—Hquid extraction. SiUca-gel adsorption or one of the similar Hquid—soHd techniques may also be used to further purify the product streams. 

Plutonium(III) in aqueous solution, Pu " ( 4)> is pale blue. Aqueous plutonium(IV) is tan or brown the nitrate complex is green. Pu(V) is pale red-violet or pink in aqueous solution and is beUeved to be the ion PuO Pu(VI) is tan or orange in acid solution, and exists as the ion PuO. In neutral or basic solution Pu(VI) is yellow cationic and anionic hydrolysis complexes form. Pu(VII) has been described as blue-black. Its stmcture is unknown but may be the same as the six-coordinate NpO (OH) (91). Aqueous solutions of each oxidation state can be prepared by chemical oxidants or reductants... 

Evidence foi the anionic complex PuCP is the precipitation of complex halides such as Cs2PuClg from concentrated HCl (aq). The ability of Pu(IV) to form stable nitrate complexes provides the basis for the Purex and ion-exchange (qv) process used in the chemical processing of Pu (107). Pu(VI) is similar to Pu(IV) in its abihty to form complex ions. Detailed reviews of complex ion formation by aqueous plutonium are available (23,94,105). 

There is reasonable evidence for the formation of aqueous U(IV) nitrate complexes of general formula where n = 1-4. However, owing... 

U(IV) nitrates have been obtained from aqueous solution, but a number of anionic complexes of general formula M2[U(N02)g], where M = NH Rb, Cs, and M[U(N02)g] 8H20, where M = Mg, Zn have been isolated and characterized. These soHds contain the 12 coordinate anionic U(IV) center shown in (2) (158). Neutral, U(IV) nitrate complexes of formula U(N02)4L2 (3) (L = OP(CgH )2, OP(NC4Hg)2) have also been isolated from aqueous solutions and stmcturaHy characterized (159). 

Di-n-amyl n-amylphosphonate [6418-56-0] M 292.4, b 150-151°/2mm, n 1.4378. Purified by three crystns of its uranyl nitrate complex from hexane (see tributyl phosphate). Extracts Zr " from NaCl solns. 

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 45, 71 Sodium amide, in alkylation of ethyl phenylacetate w ith (2-bromo-ethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1 bromobutane to give 2,4-nonanedione, 47, 92 Sodium 2 ammobenzenesulfinate, from reduction of 2 mtrobenzenesul-finic acid, 47, 5... 

Complex wtih Dicupric Pentaazide Ion, MeNH2Ph+.Cu(N3)s, C7HloCu2N16, mw 445.29, N 50.13% fine brown needles which decomp at 80° and deton sharply at 203° prepd by the action of Na azide on the above nitrate complex... 

Stability constants, enthalpies, and entropies determined in the Pu(IV)-HS0I system are presented in Table IV. The enthalpy and entropy for each of the complexation steps were determined by a van t Hoff plot of the stability constant data. These stability constants include a correction for nitrate complexing of Pu(IV) [(Kj = 2.88 (13)) [N0j] = 0.074 M]. Error limits of the... 

Covalent Organotin Halide, Pseudohalide, Carboxylate, and Nitrate Complexes... 

The ability of cobalt(II), nickel(II), and copper(II) to exhibit a greater tendency than Zn(II) towards bidentate coordination is further illustrated by structural comparisons within a series of bridging carbonate complexes (188). For example, of the complexes [TpPr 2]M 2(/x-C03) (M = Mn, Fe, Co, Ni, Cu, Zn), only the zinc derivative does not exhibit bidentate coordination at both metal centers (151,153). Furthermore, the carbonate ligand in the complexes [TpPr 2]M 2(/x-C03) (M = Mn, Fe, Co, Ni, Cu) also exhibits varying degrees of asymmetry that closely parallel the series of nitrate complexes described earlier (Fig. 47 and Table IX). 

There has been particular recent interest in zinc nitrate complexes as coordination models for bicarbonate binding in carbonic anhydrase. The mono- or bidentate coordination modes have been studied with tris-pyrazolyl borate complexes and can be rationalized in the context of the enzyme activity.433 Caution in this comparison is introduced by ab initio calculations on these model systems demonstrating both monodentate and bidentate coordination energy minima for nitrate binding to zinc 434... 

The zinc nitrate complexes of pyridyl functionalized 12[ane]N3 ligands l-(2-pyridylmethyl) -1,5,9-triazacyclododecane and l-(2-pyridyl-2 -ethyl)-l,5,9-triazacyclododecane were formed. 13C NMR studies were used to determine conformation in solution suggesting the former gave a trigonal bipyramidal isomer in solution with a water bound and the latter gave a 2 1 mixture of tetrahedral and asymmetric trigonal bipyramidal isomers. The crystal structure of the zinc complex of l-(2-pyridyl-2 -ethyl)-1,5,9-triazacyclododecane reveals a tetrahedral geometry in the solid state.679... 

Buffinger, D. R., et al J. Coord. Chem., 1988, 19(1-3), 197 A double salt of the nitrate and the copper(II) salt of an organometallic ligand was found to explode at around 100°C. In view of the oxidising powers of the nitrate, complexes of this nature are not likely to be stable. 

The reaction of the tetranuclear mercuracarborand 166 with 2 or 3 equiv. of KNO3/I8-C-6 in acetone affords two different nitrate complexes namely [166-(N03)2(H20)]2 and [166-(N03)2]2 (Figures 15 and 16). In both cases, the nitrate anions are ligated to the mercury centers by Hg-O interactions ranging from 2.60 to 3.08 A. In [166-(N03)2]2, the two anions coordinate with all four mercury atoms in a face-on trihapto fashion from either side of the plane.216... 

Bi2S3, Bi2Se3. Bismuth nitrate complexed with triethanolamine or EDTA and thioacetamide, with the addition of hydrazine hydrate, have been... 

Silver nitrate complexed with ethylenediamine and glucose and other reducing agents have been used to grow silver films by SILAR. After annealing at 300 °C the films showed cubic structure and the I-V curves exhibited linear behavior, whereas the as-grown films showed nonlinear behavior.125... 

Lead nitrate complexed with EDTA and lead perchlorate and sodium sulphide have been used for PbS ECALE-deposition.158159 The films were cubic and highly (200) oriented, and AFM images showed the same cubic structure.158159 PbSe films were also cubic, and the band gap of a film after 50 deposition cycles was 8000cm-1.160 PbSe/PbTe superlattices, with 4.2-nm and 7.0-nm periods, have been grown by ECALE.161 The (111) reflection in the XRD pattern showed a first-order satellite peak and one second-order peak, indicating the formation of the superlattice. AFM images of the superlattice structure showed a small amount of three-dimensional growth.161... 

SbClt, Gad , AuClj, T1C1, FeCij extraC( many metals including U(VI), Co, Fe(III), Mo(VI), Ta, Ti(III), Zn as halide, sulphate or nitrate complexes... 

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 46, 71 Sodio-2-formyl-6-methylcyclohexanone, 48,41... 

Torsional barriers for trimethylphosphine derivatives (63) have been obtained from Raman spectra.56 Vibrational spectra for the uranyl nitrate complex of (63a) have been published.66 Complexes of triarylphosphine derivatives (64) with iodine,67 and of (64b) with metal halides,68 have been the subject of thermodynamic67 and spectroscopic67 68 study. 

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