Peter Schwendt's research while affiliated with Comenius University Bratislava and other places

Publications (90)

Article
Full-text available
Two new 1D polymeric heterometallic copper–vanadium compounds were prepared. The polymers are constructed from [Cu(im)4]²⁺ cations that are coordinated to two terminal oxido ligands of [V2O4(mand)2]²⁻ anions. The stronger coordination in [Cu(im)4V2O4(mand)2]n (1) that contains the racemic mandelato ligand is manifested by a shorter Cu‒O bond distan...
Article
A new mononuclear vanadium peroxido complex [VO(O2)(phen)(quin)]·H2O (1) exhibiting an unprecedented isomerism of its ligands was isolated from a two-component water–acetonitrile solvent system. DFT computations aimed at inspecting the stability of all possible isomers of complexes [VO(O2)(L1)(L2)], where L1 and L2 are NN+ON, OO+ON, NN+OO, and ON+O...
Article
Full-text available
A nickel‒vanadium metal–organic hybrid compound [Ni(phen)3]2[(V2O2(O2)2((S)-mand)2)][(V2O2(O2)2((R)-mand)2)]·18H2O (phen = 1,10-phenanthroline, mand²⁻ = mandelato(2−) ligand, C6H5–CO–COO²⁻) (1) was prepared and characterized by spectral methods, X-ray structure analysis and simultaneous DTA and TG measurements. The crystal structure of 1 contains b...
Article
Full-text available
New vanadium complexes of mandelic acid (NMe4)4[V2O4((R)-mand)2][V2O4((S)-mand)2] (1) (NMe4)2[V2O4((S)-mand)2]·H2O (2) (NEt4)2[V2O4((S)-mand)2]·H2O (3) (PPh4)2[V2O4((R)-mand)((S)-mand)]·2H3CCOCH3·2H2O (4), (NH4)2.5(NEt4)0.5[V3O7((R)-mand)((S)-mand)]·2H2O (5) (mand2− = mandelato ligand) have been synthesized and characterized by single crystal X-ray...
Article
Two novel heterometallic complexes [Cu(bpy) 2 V 2 O 2 (O 2 ) 2 (R-mand) 2 ][Cu(bpy) 2 V 2 O 2 (O 2 ) 2 (S-mand) 2 ]·2CH 3 CN·2H 2 O (1), and [Cu(phen) 2 V 2 O 2 (O 2 ) 2 (R-mand) 2 ][Cu(phen) 2 V 2 O 2 (O 2 ) 2 (S-mand) 2 ]·2CH 3 CN·2H 2 O (2), (mand = mandelato(2–) = C 6 H 5 CH(O)CO 22– ) were prepared and characterized by spectral methods. X-ray...
Article
Complex NH4[VO(O2)2(NH3)] (1) undergoes an order-disorder phase transition at Tc~258K. This transition is accompanied by change in the space group of the orthorhombic lattice and also by significant structural rearrangements of the constituent molecules, which are pertinent mostly to their NH4+ ions and their ammonia ligands. The low-temperature so...
Article
All stereoisomers of isoleucine were transformed to the mixtures of the corresponding epimers by epimerization in alkaline aqueous solution. The catalyst was formed in situ by condensation of salicylaldehyde and isoleucine followed by complexation with vanadate. No derivatization of the amino acid was necessary. The tetrabutylammonium salts of [VO2...
Article
Peroxido complexes represent an important group of vanadium compounds having practical applications in distinct areas of chemistry. They possess insulin mimetic properties, antitumor activity and stimulate or inhibit certain enzymes. The bioinorganic chemistry of peroxidovanadates studies also the role of vanadium in the active centers of vanadium...
Article
The first peroxidovanadium trimer was prepared in the form of its tetrabutylammonium salt (NBu4)3[V3O3(O2)6]·2H2O. Its X-ray structure analysis revealed a unique cyclic structure of the [V3O3(O2)6]3− ion incorporating the yet unobserved μ3-η2:η1:η1 coordination mode of one of its peroxido ligands. While relatively stable in nonaqueous solvents, the...
Article
The synthesis and structure of the first vanadium diperoxido complex carrying a monodentate amine ligand coordinated solely through its –NH2 group is reported herein. (S)-methylbenzylamine (mba) is acting as a ligand, while its protonated form is the cation in mbaH[VO(O2)2(mba)]∙H2O (1), which was isolated from a solution obtained by dissolving van...
Article
We present the crystal structures and spectral characterization of two glycolato peroxido complexes of vanadium(V) with divalent cations. Assignment of their experimental infrared and Raman solid-state spectra was corroborated by gas-phase and periodic density functional calculations. First, the conventional BP86, PBE, and B3LYP exchange–correlatio...
Article
The structures of two stereoisomers of the chiral anion [VO2(N-salicylidene-isoleucinato)]− possessing three centers of chirality, the vanadium atom (configuration A/C) and the isoleucine moiety (configuration R/S on alpha and beta carbons), are presented. The absolute configuration of all available stereosiomers, CSS, ARR, CSR and ARS, was determi...
Article
(NMe4)4 [V12O30F4(H2O)2] ·9H2O is synthesized from V2O5 dissolved in a solution of NMe4OH (ice bath), followed by addition of H2O2 and HF solutions (4 °C, 6 d, 12% yield).
Article
A new synthetic strategy for one‒pot synthesis of a fluorinated isopolyvanadate, (NMe4)4[V12O30F4(H2O)2]∙9H2O, utilizing peroxido vanadate intermediates, and the stepwise characterization of the reaction mixture is reported herein. The characterization of the title compound was done by single-crystal X-ray diffraction and IR spectroscopy and the re...
Article
Full-text available
Five new chiral dioxidovanadium Schiff base complexes derived from L-valine, L-leucine, L-histidine, L-threonine and D-threonine were synthesized and characterized by elemental analysis, 1H and 51V NMR and IR spectra. The absolute configurations of the complexes were determined by X-ray single crystal analysis in solid state and by electronic and v...
Article
Full-text available
Four new compounds composed of chiral complex cations and anions: D-[Fe(bpy)3] K-[Fe(bpy)3][V4O8((2R,3R)- tart)2]�12H2O (1), D-[Fe(bpy)3]2K-[Fe(bpy)3]2[V4O8((2R,3R)- tart)2][V4O8((2S,3S)-tart)2]�24H2O (2), D-[Ni(bpy)3]K-[Ni- (bpy)3][V4O8((2R,3R)-tart)2]�12H2O (3) and D-[Ni(bpy)3]2K- [Ni(bpy)3]2[V4O8((2R,3R)-tart)2][V4O8((2S,3S)-tart)2]�24H2O (4) ha...
Article
Reported herein is a simple synthetic and crystallization procedure for sequential isolation of two stereoisomers of isoleucine-derived vanadium(V) complexes from a racemic mixture with three stereogenic centers and therefore eight hypothetical species. The products of this crystallization were characterized by electronic and vibrational circular d...
Article
Reported herein is a simple synthetic and crystallization procedure for sequential isolation of two stereoisomers of isoleucine-derived vanadium(V) complexes from a racemic mixture with three stereogenic centers and therefore eight hypothetical species. The products of this crystallization were characterized by electronic and vibrational circular d...
Article
Two novel heterometallic complexes [Cd(NH3)6][{VO(O2)2(OH)}2{μ-Cd(NH3)4}] (2) and [{VO(O2)2(Im)}2{μ-Cu(Im)4}] (3) (Im = imidazole) containing peroxidovanadium complexes as metalloligands were prepared and characterized by spectral methods. X-ray single-crystal analysis revealed the presence of unique trinuclear complexes in the crystal structures o...
Article
Full-text available
The first transition metal iodato peroxido complex, K3[V2O2(O2)4(IO3)]·H2O (I), was prepared by crystallization from the KVO3 — KIO3 — H2O2 — H2O — ethanol (HNO3) solution. The dinuclear anion is immediately decomposed in aqueous solution; the 51V NMR spectrum exhibits signals corresponding to [VO(O2)2(H2O)]−, [V2O2(OH)(O2)4]3− and H2VO4 − species...
Article
Full-text available
The synthesis, structural characterization, magnetic and catalytic properties of a new class of lanthanide-containing cationic heteropolyoxovanadium clusters with a nanochocolate-like structure are reported. The title compounds were characterized by single-crystal and powder X-ray diffraction, IR and 51V-NMR spectroscopies and magnetic susceptibili...
Article
Two new compounds containing chiral cations and anions, [M(bpy)3][VO(O2)(ox)(bpy)]2⋅7H2O (M = Fe, Ni; bpy = 2,2′-bipyridine; ox = oxalato(2–)) have been prepared and characterized by elemental analysis, vibrational spectra in the solid state, and by 51V NMR and electronic spectroscopy in solution. The compounds are isostructural and racemic. The cr...
Data
Full-text available
The synthesis, structural characterization, magnetic and catalytic properties of a new class of lanthanide-containing cationic heteropolyoxovanadium clusters with a nanochocolate-like structure are reported. The title 10 compounds were characterized by single-crystal and powder X-ray diffraction, IR and 51 V-NMR spectroscopies and magnetic suscepti...
Article
Diperoxidovanadium complex with 1,10-phenanthroline, [N(C4H9)4]{[VO(HO2)(O2)(phen)][VO(O2)2(phen)]}⋅3H2O2⋅ H2O (1), has been prepared and characterized by infrared, Raman and 51V NMR spectra. X-ray structure analysis revealed the presence of dinuclear anion in 1 in which the [VO(HO2)(O2)(phen)] and [VO(O2)2(phen)]− entities are connected via a shor...
Article
Two new compounds containing decavanadate ions coordinated to copper centers, (2-hepH+)2[{Cu (H2O)2(O,N-2-hep)}2V10O28].6H2O(2-hepH+ = 2-(2-hydroxyethyl)pyridinium; 2-hep = 2-(2-hydroxyethyl) pyridine) (1), [{Cu(2-amp)2(H2O)}2H2V10O28].4H2O(amp = 2-(aminomethyl)pyridine) (2), have been prepared and characterized by elemental analyses and IR spectro...
Article
The oxalato complex (EnH(2))(2)[V2O2(O-2)(4)(mu-C2O4)] (where En = ethane-1,2-diamine) has been prepared and characterised by elemental analysis, infrared and Raman spectra and single crystal X-ray analysis. The crystal structure is stabilised by an extensive network of simple, bi-, tri- or tetrafurcated N - H . . . O hydrogen bonds which is suppos...
Article
The review is dealing with monoperoxidovanadium (V) complexes, intensively studied in many laboratories during the last decades, due to their importance in biocoordination chemistry which is based mainly on the fact that they represent synthetic structural and functional models for the peroxo form of the vanadium haloperoxidase enzyme (VHPO), or ca...
Article
The decavanadate with a novel glycine–glycinato complex of copper (II) in the cationic part, (NH4)2[Cu2(H2O)4(NH3CH2COO)2(NH2CH2COO)2]H2V10O28·6H2O (1), has been prepared and characterized by elemental analysis, infrared and EPR spectroscopies. The triplet X band EPR spectrum of powdered sample evidenced magnetic interaction between the Cu(II) atom...
Article
Vanadium(V) oxido peroxido tartrato complexes have been prepared from aqueous-ethanolic media and characterized by spectroscopic methods. Using racemic tartaric acid for the synthesis, the simultaneous crystallization of racemic compounds (racemic phases) and racemic conglomerates (chiral phases) has been observed. The X-ray crystal structure of (N...
Article
Decavanadates with complex cations, (NH4)2[Zn(H2O)5(NH3CH2CH2COO)]2V10O28·4H2O (4) and (NH4)2[Mn(H2O)5(NH3CH2CH2COO)]2V10O28·2H2O (5), have been prepared and characterized by elemental analysis, i.r., Raman, UV–vis. and 51V-n.m.r. spectroscopies and by thermal analysis. The X-ray structure determination revealed, both in 4 and 5, the presence of co...
Article
The decavanadate with a novel glycine–glycinato complex of copper (II) in the cationic part, (NH4)2[Cu2(H2O)4(NH3CH2COO)2(NH2CH2COO)2]H2V10O28·6H2O (1), has been prepared and characterized by elemental analysis, infrared and EPR spectroscopies. The triplet X band EPR spectrum of powdered sample evidenced magnetic interaction between the Cu(II) atom...
Article
The first dinuclear nonperoxido tartrato complexes of vanadium(V), (NMe(4))(2)[V(2)O(4)((2R,3R)-H(2)tart)(2)] x 6 H(2)O (1), (NMe(4))(2)[V(2)O(2)((2R,3R)-tart)((2S,3S)-tart)] (2), (NEt(4))(2)[V(2)O(2)((2R,3R)-tart)((2S,3S)-tart)] (3) (tart = tartrato(4-) = C(4)H(2)O(6)(4-)) have been prepared from water-ethanol medium and characterized by X-ray str...
Article
Full-text available
The structure of the title compound, (C(7)H(10)NO)(2)[Mn(2)V(10)O(28)(H(2)O)(10)].4H(2)O or (C(5)H(4)NHCH(2)CH(2)OH)(2)[{Mn(H(2)O)(5)}(2)V(10)O(28)].4H(2)O, at 293 (2) K has triclinic (P\overline{1}) symmetry. The asymmetric unit consists of one half of a decavanadate anion of C(i) symmetry, one [Mn(H(2)O)(5)](2+) group, one 2-(2-hydroxyethyl)pyrid...
Article
Full-text available
Two new dinuclear fluoro peroxovanadium(v) complexes, Cs3[V2O2(O2)4F] x H2O (1) and Cs3[V2O2(O2)3F3] x 2HF x H2O (2), were prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and X-ray crystallography. While the anion in possesses an asymmetric structure with a micro-eta1:eta2 bridging peroxo group, the [V2O2(O2)3F3]...
Article
The structure of the title compound, (C7H10NO)2[Mn2V10O28(H2O)10]·4H2O or (C5H4NHCH2CH2OH)2[{Mn(H2O)5}2V10O28]·4H2O, at 293 (2) K has triclinic (P) symmetry. The asymmetric unit consists of one half of a decavanadate anion of Ci symmetry, one [Mn(H2O)5]2+ group, one 2-(2-hydroxyethyl)pyridinium cation and two solvent water molecules. The decavanada...
Article
A new polymeric inorganic–organic hybrid compound, (NH4)2[Cu2(NH3CH2CH2COO)4(V10O28)] · 10H2O, (1) has been synthesized and characterized by IR, electron and EPR spectroscopy. The thermal decomposition of 1 is briefly described. The structure of 1 consists of Cu2(NH3CH2CH2COO)44+ moieties which are connected by bridging V10O286− ions into polymeric...
Article
The compounds [{VO(O2)2(NH3)}2{μ-Cu(NH3)4}] (1) and [Zn(NH3)4][VO(O2)2(NH3)]2 (2) were prepared and characterized by elemental analysis and infrared spectra. The single crystal X-ray study revealed that the structure of 1 consists of trinuclear complex molecules [(NH3)OV(O2)2{μ-Cu(NH3)4}(O2)2VO(NH3)] with a rare heterobimetalic peroxo bridge: coppe...
Article
Full-text available
The compound [Ni(NH3)6][VO(O2) 2(NH3)]2 was prepared and characterized by elemental analysis and vibrational spectra. The single crystal X-ray study revealed that the structure consists of [Ni(NH3)6] 2+ and [VO(O2)2(NH3)]- ions. As a result of weak interionic interactions V •••O p (Op-peroxo oxygen), ([VO(O2) 2(NH3)]-)2 dimers are formed in the sol...
Article
A study of the aqueous H3O+(OH-)/H2VO4-/(2R,3R)-tartrate system has been performed at 273 K in a 1.0 mol/L Na+(Cl-) ionic medium using 51V NMR spectroscopy. In this relatively complicated system, more than 12 different species were observed. Ligand concentration, vanadate concentration, and pH variation studies were carried out, particularly for th...
Article
The presence of the [VO(O2)2F]2− ion in an aqueous solution gives rise to a doublet (δ = −714 ppm, JVF = 163 ± 3 Hz) in the 51V NMR, and a multiplet (δ = −160 ppm, Δν1/2 = 1163 Hz) in the 19F NMR spectrum. The formation of this species is enhanced in formamide solutions. The ethane-1,2-diammonium(2+) fluorooxodiperoxovanadate, [NH3CH2CH2NH3][VO(O2)...
Article
The presence of the [VO(O2)2F]2− ion in an aqueous solution gives rise to a doublet (δ=−714ppm, JVF=163±3Hz) in the 51V NMR, and a multiplet (δ=−160ppm, Δν1/2=1163Hz) in the 19F NMR spectrum. The formation of this species is enhanced in formamide solutions. The ethane-1,2-diammonium(2+) fluorooxodiperoxovanadate, [NH3CH2CH2NH3][VO(O2)2F], was prepa...
Article
The peroxo complexes formed by vanadium (V) in the presence of rac- or S-3-phenyllactic acid as heteroligand, M2[V2O2(O2)2(rac-3-phlact)2] · nH2O (M+ = K+ (1), NMe4+ (3), NBu4+ (6)), M2[V2O2(O2)2(S-3-phlact)2] · nH2O (M+ = K+ (7), NH4+ (8), NMe4+ (9), NEt4+ (10), NPr4+ (11), NBu4+ (12)), (NH4)4[V2O2(O2)2(R-3-phlact)2][V2O2(O2)2(S-3-phlact)2] · 2H2O...
Article
Monoperoxovanadium(V) complexes, [NH3(CH2)2NH3][VO(O2)(ox)(pic)]·2H2O (1) and [NH3(CH2)2NH3][VO(O2)(ox)(pca)] (2) [NH3(CH2)2NH3 = ethane-1,2-diammonium(2+), ox = oxalate(2−), pic = pyridine-2-carboxylate(1−), pca = pyrazine-2-carboxylate(1−)], were synthesized and characterized by X-ray analysis, IR and Raman spectroscopies. The five equatorial pos...
Article
The new compound, [CuCl(phen)2]3H3V10O28 · 7 H2O, was prepared by reaction of an aqueous KVO3 solution (pH 3) with an aqueous solution of CuSO4 · 5 H2O in which 1,10-phenanthroline (phen) and KCl were added. The crystal structure of the compound was determined, and the proton position in H3V10O283– were calculated by the bond length/bond number met...
Article
Peroxovanadium(V) complexes of α-hydroxyhippuric acid (α-H2hhip), M 2[V2O2(O2)2(α-hhip)2]·nH2O, [M=K+(1), NH4+(2), NEt 4+(3), NBu 4+(4); n=5.5, 3, 8, 5) have been prepared and characterized by elemental analysis, i.r., u.v.–vis. and 51V-n.m.r. spectroscopies and by thermal analysis. The X-ray structure determination of (4) revealed the presence of...
Article
Peroxovanadium(V) complexes of α-hydroxyhippuric acid (α-H2hhip), M2[V2O2(O2)2(α-hhip)2] · nH2O [M=NMe4+ (1), NPr4+ (2); n=0.5, 5], have been prepared and characterized by elemental analysis and by IR and Raman spectroscopies. The X-ray crystal structure of 2 has been determined as the first crystal structure of an α-hydroxyhippurato complex. A sin...
Article
Vanadium(V) oxo peroxo mandelato complexes were prepared from aqueous solution and characterized by elemental analysis, IR, UV–Vis and 51V NMR spectroscopies. The single crystal X-ray studies of (NMe4)2[V2O2 (O2)2(R,S-mand)2] · 6.5H2O (3), (NMe4)(NH4)[V2O2(O2)2(R,S-mand)2] · 2H2O (4) and (NEt4)2[V2O2(O2)2(R-mand)2] (8) revealed that the mandelato l...
Article
Two new racemic monoperoxo complexes of vanadium(V), K[VO(O2)(ox)(bpy)]·3H2O (1) and Pr4N[VO(O2)(ox)(phen)] (2) [bpy=2,2′-bipyridine, phen=1,10-phenanthroline, ox=oxalate(2−) and Pr4N=tetra(n-propyl)ammonium(1+)], were synthesized. The solid complexes were characterized by X-ray structure analysis and IR and Raman spectroscopies. The coordination p...
Article
Reactions in the CuSO4-phen-KVO3-H2O (KOH, ethanol) systems yielded two new compounds [Cu-2(phen)(2)V4O12] . 5H(2)O, 1, and [Cu(phen)(3)](VO3)(2) . 20H(2)O, 2 (phen = 1,10-, phenanthroline). A structure, containing a V4O124- cluster to which Cu(phen) fragments are attached through Cu-O bonds, was proposed for 1, while 2 is probably constructed from...
Article
The oxalatooxoperoxovanadates(V) (H3dien)[VO(O2)(C2O4) 2] · H2O (I), (H3tren)[VO(O2)-(C2O4) 2] · 3H2O (II), (Hampic)3[VO(O2)(C2O4) 2] · 2H2O (III), and (Hampic)3[VO(O2)2(C2O 4)] · 4H2O (IV) (dien = diethylenetriamine, tren = tris(2-aminoethyl)amine, ampic = 2-amino-3-methylpyridine) have been prepared and characterized by elemental analyses and IR...
Article
An overview of structurally characterized alpha-hydroxycarboxylatodioxo- and alpha-hydroxycarboxylatooxoperoxovanadates(V) is presented and the geometric parameters of the V2O2 bridging core are discussed. The first case of a stereospecific formation of oxoperoxovanadates(V) is reported: The crystal structures of the isomeric compounds (NBu4)2[V2O2...
Article
The crystal structure of the title complex, bis­(tetra-n-butyl­ammonium) bis(--hydroxy­benzene­acetato)-1κ2O1,O2:2κO2;1κO2:2κ2O1,­O2-bis­[oxo­(peroxo)­vanadium(V)] α-hydroxy­benzene­acetic acid solvate, (C16H36N)2­[V2O2(O2)2(C8H6O3)2]·C8H8O3, consists of dimeric anions with twofold rotation symmetry, cations and mol­ecules of mandelic acid. Deproto...
Article
 Oxo peroxo glycolato complexes of vanadium(V) (M 2[V2O2(O2)2(C2H2O3)2]ċnH2O (n=0, 1; M=NBu4 + (1), K+ (2), NH4 + (3), Cs+ (4), NPr4 + (5)) as well as (NBu4)2[V2O4(C2H2O3)2]ċ H2O (6) have been prepared and characterized by spectroscopic methods. X-Ray structure analysis of 1 revealed the presence of dinuclear [V2O2(O2)2(C2H2O3)2]2− anions with a (c...
Article
Vanadium(V) oxo peroxo tartrato complexes M2[{VO(O2)(L-tartH2}2(μ-H2O)]. 5H2O (M = K+, NH4+; tart4− = C4O6H24− have been prepared from aqueous-ethanolic medium and characterized by elemental analysis and IR spectroscopy. The X-ray crystal structure of K2[{VO(O2) (L-tartH2)}2(μ-H2O)]. 5H2O, as the first crystal structure of a vanadium(V) tartrato co...
Article
The crystal structure of (Bu4N)(2) [VO2(C4H6O3)](2).2H(2)O consists of the dimeric [{VO2(C4H6O3)}(2)](2-) anion with C-i symmetry, two Bu4N+ cations and two water molecules. The V atom is pentacoordinated by O atoms in a tetragonal-pyramidal arrangement.
Article
Compounds crystallizing from theMOH-HF-V2O5-H2O2-H2O (M=N(CH3)4, N(C2H5)4, N(C4H9)4) system have been characterized by elemental analysis, vibrational spectra, and X-ray powder patterns. Besides [N(CH3)4]2[VO(O2)2F]·2H2O (1) and [N(CH3)4]3[V2O2(O2)4F] (2) which correspond to the known compoundsM 2[VO(O2)2F] (M=K, NH4, Cs) and (NH4)3[V2O2(O2)4F]·2H2...
Conference Paper
Complexes (Bu4N)(2) [VO(O-2)(LL)](2) . H2O where Bu = C4H9 LL = glycolate C2H2O2- (I), or DL-lactate C3H4O2-(II), have been prepared and characterized by X-ray and spectral methods. Complexes I and II are able to hydroxylate benzene under mild conditions.
Article
The vanadium(V) peroxo phosphato complex K7[V4O4(O2)8(PO4)]·9H2O has been obtained from the KVO3KH2PO4KOHH2O2H2OC2H5OH system. The X-ray structural analysis revealed a tetranuclear anionic structure in which two dinuclear [V2O2(O)2)2(μ-η1 : η2-O2)2] units are connected by the μ4-PO4 group.
Article
Infrared spectra of solutions of M<sub>2</sub>[V<sub>2</sub>O<sub>2</sub>(O<sub>2</sub>)<sub>4</sub>H<sub>2</sub>O] . aq (M = N(CH<sub>3</sub>)<sub>4</sub>, N(C<sub>4</sub>H<sub>9</sub>)<sub>4</sub>) in heavy water and acetonitrile indicate that in concentrated solutions ( c >= 0.5 mol dm<sup>-3</sup>) the asymmetric structure of the [V<sub>2</sub>...
Article
The monoperoxo complexes, M2[VO(HEDTA)(O2)] 4H2O, where M is K+ or NH 4 + and H4EDTA is ethylene-diaminetetraacetic acid, were prepared and characterized by Raman and i.r. spectra in the solid state and in aqueous solution. The single crystal X-ray study revealed a pentagonal bipyramidal anion structure with a tetradentate HEDTA(3—) ligand. The dec...
Article
From the reaction systems,B-V2O5-HClO4-H2O andB-V2O5-H2O, whereB is benzylamine (Bz), imidazole (Im) or pyridine (Py), eight new compounds were synthesized: at 20°C, the metavanadate and decavanadates of composition (BzH)VO3, (BzH)6V10O28·3H2O, (ImH)6V10O28·2H2O, (PyH)6V10O28·2H2O, (ImH)4H2V10O28·2H2O and (PyH)4H2V10O28·3H2O, and at 60°C, the hexav...
Article
The thermal decomposition of K3[OH{VO(O2)2}2]·H2O was studied under dynamic conditions up to 350°C and also isothermally at 150°±3°C in self-generated atmosphere. K4[V2O6(O2)] is formed as the reaction intermediate. The final products of thermal decomposition of K3[OH{VO(O2)2}2]·H2O are KVO3 and K4V2O7.
Article
M2[VO(nta)(O2)]xH2O, where M+ is NH inf4 p+ , K+ or Rb+ and nta is nitrilotriacetate, and Sr[VO(nta)(O2)]2H2O were synthesized. The electronic spectra of aqueous KVO3-H2O2-H3nta-HClO4(KOH) solutions (pH 1.45–5.62) and the thermal decomposition of K2[VO(nta)(O2)] 2H2O with active oxygen release at 275 C showed that the nta-monoperoxo complex is the...
Article
The thermal decomposition of K2[VFO(O2)2], proceeding isothermally at 114 and 175°C in a self-generated atmosphere or under dynamic conditions up to 240°C, is a multi-step process. The unstable intermediate formed in the first stage of the decomposition reacts to form a mixture of KVO3, KF, K3VF4O2 and K4[V2O6(O2)]. The final decomposition product...
Article
The Raman spectra of aqua- and oxalatooxodiperoxovanadates in aqueous solutions are reported. Based on correlations between the coordination number of the vanadium and the stretching mode absorptions, a pentagonal pyramidal structure is proposed for [VO(O2)2H2O]−, [VO(O2)2D2O]− and [VO(O2)2NH3]−; the [VO(O2)2C2O4]3− ion appears to be pentagonal bip...
Article
The thermal decomposition of K3[V(CO3)O(O2)2] was studied under isothermal, dynamic and quasi-isobaric-isothermal condition. A mixture of K4V2O7 and K2CO3 was identified as the primary product of thermal decomposition. Under experimental conditions not allowing a continuous loss of volatile products, the reaction of K4V2O7 with CO2 gives KVO3 and K...
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Single crystals of the title compound are obtained from the reaction of KVO3 in 15% H2O2 at 273 K. K2(V2O2(O2)4(H2O))·3 H2O crystallizes in the triclinic space group P1 with Z=1.
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K 2 [V 2 O 2 (O 2 ) 4 (H 2 O)]•3H 2 O cristallise dans P1 avec a=6,501, b=7,882 et c=7,501 A, α=107,18, β=95,50 et γ=116,20°, Z=1; affinement jusqu'a R=0,026. Le cœur de la structure est l'anion [V 2 O 2 (O 2 ) 4 (H 2 O)] 2− . Le polyedre de coordination de chaque V peut etre decrit commune une pyramide pentagonale. Presence d'un reseau de liaisons...
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The peroxovanadate (I), precipitated from aqueous solution, crystallizes in the monoclinic system, space group Cc with Z=4.