Showing papers by "Andrei V. Churakov published in 2013"

Palladium complexes with stabilized germylene and stannylene ligands.

Abstract: The syntheses of novel Pd complexes with germylene and stannylene ligands are reported. [MeN(CH2CH2NC6F5)2Sn]4Pd (2) and [MeN(CH2CPh2O)(CH2CH2O)Ge]4Pd (8) were obtained by different methods including ligand substitution in (Ph3P)4Pd or by the reaction of the free corresponding germylene or stannylene with (Ph3P)2PdCl2 or Pd(OAc)2. Crystal structures of complexes 2, 8 were determined by single crystal X-ray diffraction analysis. The catalytic activity of complexes 2, 8 was examined in the Suzuki–Miyaura and Heck cross-coupling.

Easily accessible, hydrocarbon-soluble, crystalline, anhydrous lanthanide (Nd, La, and Y) phosphates

Abstract: Nd, La and Y triphosphates were prepared via the reaction of potassium ionol ethyl phosphate with the corresponding lanthanide nitrates or chlorides in water. According to the X-ray diffraction data, the recrystallised reaction products were dimers. The products did not contain water, were readily soluble in hydrocarbon solvents and demonstrated promising catalytic properties in the polymerisation of butadiene and DL-dilactide.

Novel Stannylenes Stabilized with Diethylenetriamido and Related Amido Ligands: Synthesis, Structure, and Chemical Properties

Abstract: Complexes of divalent tin 7–12 with diethylenetriamines 1–3 and related ligands 4–6 were prepared from Lappert's stannylene, Sn[N(SiMe3)2]2, and the corresponding ligands. Reactivity of the stannylenes in insertion, oxidation and [1+4] cycloaddition reactions were studied. Composition and structures of the products were confirmed by elemental analyses and multinuclear (1H, 13C, 19F, and 119Sn) NMR spectroscopy. Crystal structures of the diethylenetriamines 1, 2, stannylenes 7, 8 and the product of the reaction of stannylene 8 with an azide, which contains an eight-membered (SnNPO)2 ring, were determined by X-ray diffraction study.

Alternating Asymmetric Self-Induction in Functionalized Pyrrolidine Oligomers**

Abstract: Artificial structurally well-defined polymers have excited interest as functional mimetics of natural biomacromolecules, exhibiting additional properties not occurring in the living world. Specific conformational organization of natural and synthetic polymeric objects leading to unique folding accounts for the molecular recognition, which is one of the driving principles in important natural processes. Some nonnatural oligomeric species adopt specific and well-defined conformations dictated by the structure of monomeric units and intramolecular interactions and are defined as foldamers. One of the most studied unnatural foldamer types are bpeptides that adopt stable folded helical, sheet, and turn-like conformations. b-Peptides are stable towards natural enzymes, and appropriate design leads to discovery of bpeptide ligands for complicated pharmaceutical targets, such as protein–protein interactions. The application of pyrrolidine-3-carboxylic acid (Pca) for the construction of bpolypeptide chain rigidifies the molecular backbone and provides additional stabilization of the secondary structure of the oligomer in solution. The typical synthesis of a b-peptide backbone is based on the arsenal of peptide chemistry methods, including routine sequences of amino group protection–deprotection steps and multiple activations of carboxylic functionality for amide bond construction. Herein we disclose a fundamentally novel synthetic method towards well-defined highly functionalized short b-peptides that avoids protection, deprotection, and activation procedures and allows to generate efficiently stereoregular oligomeric pyrrolidine-based molecules. The developed method, called cycloadditive oligomerization, has been used for the synthesis of a set of racemic and enantiopure oligomers containing a Pca backbone. The realized approach determines highly diverse structural characteristics of b-peptide oligomers, which are characterized by various physicochemical methods, including X-ray analysis. The oligomerization utilized azomethine ylide 1,3-dipolar cycloaddition as a chain-growth approach (Scheme 1). 5Arylpyrrolidine-2,4-dicarboxylate units serve both as linked elements and as auxiliaries to determine stereoand enantioselectivities of the cycloaddition process. The starting 5arylpyrrolidine-2,4-dicarboxylic acid diesters 3a (X=H, Br) for oligomer synthesis were obtained from iminoesters 1 and tert-butyl acrylate in racemic and enantiopure forms by 1,3-dipolar cycloaddition using Lewis acids for the azomethine ylide generation step (Scheme 1, Table 1). Asymmetric synthesis of the monomer ( )-3a-H was effectively conducted with the enantiopure ligand 4 on a gram scale, and single recrystallization provided the target compound with more than 99% ee. Subsequent N-acryloylation of monomers 3a with acryloyl chloride transformed them into dipolarophiles 2b with a sterically hindered amide residue connected to the ethylene fragment. We supposed that these unique dipolarophiles would induce good diastereoand enantioselectivities under iterative cycloaddition steps with iminoesters 1 (Scheme 1). Indeed, dimers 3b were effectively synthesized by cycloaddition of acrylamides 2b with Schiff bases 1 (X=H, Br) in presence of AgOAc as a Lewis acid agent for azomethine ylide generation (Table 1, entries 4–6). Comparison of H NMR spectra of the cycloaddition reaction mixtures and

Zirconium and hafnium complexes based on 2-aryl-8-arylaminoquinoline ligands: synthesis, molecular structure, and catalytic performance in ethylene copolymerization

Abstract: A general and efficient approach toward new zirconium and hafnium complexes based on 2-aryl-8-arylaminoquinoline ligands was developed. These precursors, when activated with MAO/borate cocatalyst and supported on silica, result in active olefin polymerization catalysts. The ethylene copolymers produced under industrially relevant conditions show very high molecular weights and unique microstructures defined by the multisite nature of the catalyst. A site-diversification mechanism is proposed to explain the presence of at least five individual sites, as deduced from 3D-TREF analysis of ethylene–butene copolymers.

Molecular and crystal structures of 4-acylphenyl 4'-alkyloxybenzoates

Abstract: The crystal structures of four liquid-crystal (LC) compounds belonging to 4-acylphenyl 4′-alkyloxybenzoates with the general formula C n H2n + 1-C(O)-C6H4-O-C(O)-C6H4-O-C m H2m + 1 numbered as 1/6, 1/7,2/7, and 3/7 (the numbers in the code indicate the ratios of the numbers of alkyl-chain units, n/m) are determined. Compounds 1/6 and 1/7 form smectic and nematic phases, but they are monotropic mesogens, whereas compounds 2/7 and 3/7 form only an enantiotropic smectic phase. Compound 3/7 crystallizes in two crystal modifications—triclinic with Z′ = 2 (3/7 tr ) and monoclinic with Z′ = 4 (sp. gr. P2, 3/7 mon ). All crystals consist of alternating aromatic and aliphatic regions and are characterized by the presence of weak directional interactions, such as C-H...O hydrogen bonds and π-stacking interactions. This provides the necessary conditions for the formation of a mesophase, and the existence of two types of structure-forming units is in line with the formation of a smectic phase. An explanation is proposed for the monotropic properties of 1/6 and 1/7.

Pd17In4Se4, a Metal‐Rich Palladium–Indium Selenide with an Open‐Framework Structure

Abstract: A new metal-rich palladium–indium selenide, Pd17In4Se4, was synthesized in the shape of needlelike crystals by annealing a mixture of the elements in a 7:2:1 ratio, respectively, at 750 °C for 7–10 d with subsequent cooling to room temperature. Its crystal structure was determined from single-crystal diffraction data, with the composition confirmed by energy-dispersive spectroscopy (EDS). The compound crystallizes in a new structure type [tetragonal, I4/m, a = 14.3104(7) A, c = 3.9641(4) A, Z = 2]. Its main structural units are indium-centered [Pd12In] cuboctahedra of the Cu3Au type. The key feature that differentiates the structure of Pd17In4Se4 from any known compound based on the Pd–In intermetallic motif is the terminal role of selenium atoms that results in the formation of 1D channels along the c axis. Electronic structure calculations on the DFT/full-potential linearized augmented-plane wave (FP-LAPW) level predict metallic properties and Pauli-like paramagnetic behavior for the new compound. The electron localization function (ELF) topological analysis reveals the key role of selenium lone pairs in the formation of the channels in the structure and shows the multicentered nature of the bonding in the [Pd12In] fragments.

The conditions of formation of heterometallic complexes in the GeCl 4 (SnCl 4 )-citric acid-M(CH 3 COO) 2 -H 2 O systems. The crystal and molecular structures of [M(H 2 O) 6 ][Ge(HCit) 2 ] · 4H 2 O (M = Mg, Mn, Co, Cu, Zn) and [M(H 2 O) 6 ][Sn(HCit) 2 ] · 4H 2 O (M = Mg, Co, Ni)

Abstract: Fourteen bis(citrato)germanates(IV) and bis(citrato)stannates(IV) were prepared, in particular, [M(H2O)6][Ge(HCit)2] · 4H2O (M = Mg (I), Mn (II), Fe (III), Co (IV), Ni (V), Cu (VI), Zn (VII)) and [M(H2O)6][Sn(HCit)2] · nH2O (M = Mg, n = 4 (VIII); Mn, n = 2 (IX); Fe, n = 4 (X); Co, n = 4 (XI); Ni, n = 4 (XII); Cu, n = 4 (XIII); Zn, n = 3 (XIV)) (H4Cit is citric acid). The purity and the composition of the products were determined by a set of physicochemical methods including elemental analysis, thermogravimetry, and IR spectroscopy. The structures of I, II, IV, VI, VII, VIII, XI, and XII were determined by X-ray diffractometry. All eight crystals composed of centrosymmetrical octahederal [M(H2O)6]2+ cations, [Ge(HCit)2]2− (or [Sn(HCit)2]2−) anions, and crystal water molecules are isostructural. The structural units in I, II, IV, VI, VII, VIII, XI, and XII are connected by systems of hydrogen bonds to form a three-dimensional framework.

Reactivity of polynuclear palladium carboxylate complexes towards acetonitrile: synthesis and X-ray study of Pd2(C6H4-o-C(=NH)CH3)2(CH3CO2)2 and Pd5(CH3C(=N)OC(=N)CH3)(NO)(NO2)x(RCO2)7-x.

Abstract: Reactions of the polynuclear palladium carboxylate complexes (binary palladium carboxylates and palladium nitrosyl carboxylates) with acetonitrile in some common organic solvents are described. It was found that reaction of palladium acetate Pd3(μ-CH3CO2)6 with acetonitrile and benzene leads to the formation of a binuclear complex Pd2(C6H4-o-C(NH)CH3)2(CH3CO2)2 containing molecules of orthometallated 1-phenylethanimine formed as a result of C–C-coupling of acetonitrile and benzene. Nitrosyl carboxylate complexes Pd4(NO)2(RCO2)6 promote more complicated transformations of acetonitrile that leads to the formation of coordinated acetimidic anhydride, which was found in Pd5(CH3C(N)OC(N)CH3)(NO)(NO2)x(RCO2)7−x clusters. Structures of all the complexes contained products of acetonitrile transformations and a new palladium nitrosyl carboxylate Pd4(NO)2(cyclo-C6H11CO2)6 was studied with XRD. Analysis of the structures allowed finding a “building block” of palladium nitrosyl carboxylate clusters, that is a 4-nuclear metal chain –Pd(μ-RCO2)2Pd(μ-NO)(μ-RCO2)Pd(μ-RCO2)2Pd–.

Synthesis and characterization of cobalt(II) and manganese(II) xylaratogermanates: The molecular and crystal structures of the [M(H2O)6][Ge(μ3-L)2{M(H2O)2}2] · 4H2O · nCH3CN Complexes (M = Co, n = 0; M = Mn, n = 1)

Abstract: A synthetic procedure was developed, and heteropolynuclear coordination compounds—the products of the interaction of germanium tetrachloride with xylaric (trihydroxyglutaric) acid HOOC-CH(OH)-CH(OH)-CH(OH)-COOH (H5L) and the acetates of the 3d metals Mn(II) and Co(II)—were prepared. The compounds were characterized by elemental analysis, thermogravimetry, and IR spectroscopy. The X-ray diffraction analysis of the [M(H2O)6][Ge(μ3-L)2{M(H2O)2}2] · 4H2O · nCH3CN complexes, where M = Co, n = 0 (I) and M = Mn, n = 1 (II), was performed. The crystals of I are monoclinic, a = 10.752(2) A, b = 11.830(2) A, and c = 10.772(2) A, β = 94.741(3)°, V = 1365.4(5) A3, Z = 2, space group P21/n, R1 = 0.0309 for 3200 reflections with I > 2σ(I). The crystals of II are triclinic, a = 9.5330(17) A, b = 9.7415(17) A, and c = 10.3935(18) A, α = 115.024(2)°, β = 97.580(3)°, γ = 111.535(3)°, V = 764.9(2)A3, Z = 1, space group $$P\bar 1$$ , R1 = 0.0621 for 3028 reflections with I > 2σ(I). The bimetallic anions [Ge(μ3-L)2{M(H2O)2}2]2−, the cations [M(H2O)6]2+, and crystal water molecules form the basis of compounds I and II (the acetonitrile molecule is also a constituent of compound II). In the centrally symmetrical trinuclear complex anion, the Ge(1) atom is bound to two M(1) atoms through two completely deprotonated bridging ligands. The Ge(1) atom is coordinated to the six alcohol oxygen atoms of two ligands L5− at the apexes of a distorted octahedron (the average Ge(1)-O distances in I and II are 1.8858(14) and 1.892(3)A, respectively). The coordination polyhedron of the M(1) atom in the complex anion is a strongly distorted octahedron. The base of the coordination polyhedron is formed by the two bridging alcohol oxygen atoms (the average M(1)-O distances in I and II are 2.1756(14) and 2.255(3) A, respectively) of two L5− ligands and by the oxygen atoms of two water molecules (the average M(1)-O distances in I and II are 2.0693(17) and 2.175(4) A, respectively). In the centrally symmetrical complex cation, the coordination polyhedron of the M(2) atom is a somewhat distorted octahedron. The M(2)-O(H2O) bond lengths in I and II vary in the ranges of 2.0137(17)-2.1555(17) and 2.140(5)-2.172(4) A, respectively (the average lengths are 2.0375(17) and 2.166(4) A, respectively). The cations and anions are joined by a branched system of hydrogen bonds.

Specific features of technetium mononuclear octahedral oxo complexes: A review

Abstract: The specific structural features of technetium mononuclear octahedral oxo complexes have been considered. The structures of d 2-Tc(V) mono- and dioxo complexes, d 2-Tc(V) pseudodioxo compounds (Tc(V) mono-oxo complexes with an additional multiply bonded RO− ligand), and d 0-Tc(VII) trioxo compounds are analyzed.

Molybdenum(VI) complexes with N-substituted hydroxylamines

Abstract: New molybdenum(VI) complexes with N-monoalkylsubstituted hydroxylamines have been synthesized and studied. The structure of [MoO2(C2H5NHO)2] and [MoO2(i-C3H7NHO)2], whose distinguishing feature is the bidentate chelate coordination of the ligand to molybdenum with the formation of the three-membered NMoO chelate ring, has been determined by X-ray diffraction.

Palladium ketonyl carboxylate complexes – potential models of polynuclear intermediates in olefin oxidation: formation and X-ray structure of Pd6(μ-Cl)2+x(μ-CF3CO2)4(μ,κ2-CH2C(O)CMe3)6−x (x = 0, 2)

Abstract: Reactions of Pd4(NO)4(CF3CO2)4 with olefins were studied, this Pd-cluster was shown to promote the oxidation of olefins into ketones, which were found as ketonyl ligands in complex products of the reaction; 6-nuclear palladium clusters with carboxylate and ketonyl ligands Pd6(μ-Cl)x(μ-CF3CO2)4(μ,κ2-CH2C(O)CMe3)6−x were characterized by XRD analysis.

Inner complex compounds of dioxomolybdenum(VI) with o-oxyazomethines, derivatives of substituted salicylaldehydes and tris(hydroxymethyl)aminomethane. crystal structures of two complexes [MoO(L)] · CH3OH; L = Z-substituted salicylalimines, Z = 3-NO2 and 3-OCH3

Abstract: Ten new dioxomolybdenum(VI) compounds with o-oxyazomethines, derivatives of substituted salicylaldehydes (I–X) and tris(hydroxymethyl)aminomethane, are synthesized. The structures of two of them, [MoO2(L)] · CH3OH; L = Z-substituted salicylalimines, Z = 3-NO2 (IV) and 3-OCH3 (V), are determined by X-ray diffraction analysis. Compounds IV and V have similar structures and geometric parameters. The Mo atoms are coordinated through the octahedral mode by two oxo ligands in the cis positions to each other, two O atoms, one N atom of the tridentate bis(chelating) ligand L, and the O atom of the MeOH molecule.

Molecular and crystal structures of p-heptyloxyphenyl p-hexyloxybenzoate and p-butyloxyphenyl p-heptyloxybenzoate: Mesophase design

Abstract: Two aromatic esters with the formulas C6H13-O-C6H4-C(O)O-C6H4-O-C7H15 (1) and C7H15-O-C6H4-C(O)O-C6H4-O-C4H9 (2) belonging to nematic liquid-crystal compounds were studied by X-ray diffraction. Compound 1 crystallizes in two modifications: monoclinic (1-m) and triclinic (1-tr). The crystal packing of 1 and 2 is built from alternating loosely packed aliphatic regions and closely packed aromatic regions. In crystal structures 1-m and 2, the aromatic regions are linked into chains by hydrogen bonds with the participation of the carbonyl oxygen atom of the ester group and the C-H fragment of the benzene ring, but these hydrogen bonds in 1-m are much weaker than in 2. In 1-m there are π-stacking interactions between the molecules, resulting in the formation of centrosymmetric dimers with an interplanar distance of 3.45 A. In 1-tr, the aromatic fragments form a herringbone packing motif favorable for a two-dimensional network of directional C-H...π-system interactions.

Crystal structures of pyridinemonocarboxylic acid peroxosolvates

Abstract: The crystal structures of new peroxosolvates of the following pyridinemonocarboxylic acids were studied: picolinic 2-C5H4NCOOH·H2O2 (1), nicotinic 3-C5H4NCOOH·H2O2 (2), and isonicotinic 4-C5H4NCOOH·2H2O2 (3). In these compounds, the acids exist exclusively as zwitterions, as opposed to non-solvated crystals. In compounds 1–3, the hydrogen peroxide molecules form two donor hydrogen bonds and, in some cases, one additional acceptor hydrogen bond. Peroxosolvate 2 can be considered as a novel drug formulation of vitamin B3.

Strategy for the synthesis of Di- and polymer tartratogermanates with single-charge cations. Crystal structures of K2[Ge2(OH)2(μ-Tart)2] · 4.5H2O and (NH4)2n [Ge2(μ-O)(μ-Tart)2] n · nMeCN · nH2O

Abstract: Tartratogermanates of alkaline metals and ammonium are synthesized for the first time using different solvents (water, acetonitrile) and starting reagents (GeO2 and GeCl4): dimeric Kat2[Ge2(OH)2(μ-Tart)2] · 4.5H2O (H4Tart is D-tartaric acid, Kat = Na (I) and K (II)) and polymer (NH4)2n[Ge2(μ-O)(μ-Tart)2]n · nCH3CN · nH2O (III). The complexes are characterized by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. The structure of complex II contains binuclear isolated [Ge2(OH)2(μ-Tart)2]2-complexes. In complex III, the oxo ligands join the binuclear fragments into polymer chains.

Bromination of 6-dibromomethyl-6-methylcyclohexyl-2,4-dien-1-one

Abstract: Bromination of 6-dibromomethyl-6-methylcyclohexyl-2,4-dien-1-one (I) with molecular bromine was studied at different ratios of reactants and varied reaction time. A number of tri-, tetra-, penta-, and hexabromo derivatives was obtained, which were characterized by 1H, 13C, IR, UV spectroscopy and elemental analysis. The molecular structure of (2R,3R,4S,5S,6R)-2-dibromomethyl-2-methyl-3,4,5,6-tetrabromocyclohexan-1-one (V) was revealed using XRD. It was shown that 2-bromo-6-dibromomethyl-6-methylcyclohexyl-2,4-dien-1-one (III) upon standing for six months at room temperature dimerized quantitatively via Diels-Alder reaction to form IX. Dimer IX was investigated by the methods of cyclic voltammetry (CVA) and rotating disk electrode (RDE) in a solution of DMF on glassy carbon electrode.

{2,2'-[Ethane-1,2-diylbis(nitrilo-methan-yl-yl-idene)]diphenolato}(iso-propano-lato)aluminium di-chloro-methane hemisolvate.

Abstract: In the title compound, [Al(C16H14N2O2)(C3H7O)]·0.5CH2Cl2, the salen complex is monomeric and the dichlormethane solvent mol­ecule lies on a crystallographic twofold axis. The central Al atom is fivefold coordinated and possesses a square-based pyramidal environment. The Al—OAlk(iprop­yl) bond [1.7404 (14) A] is much shorter than the Al—OAr(salen) bond lengths [1.7974 (15) and 1.8094 (14) A]. The iso­propyl­oxo group forms an intra­molecular C—H⋯N hydrogen bond. In the crystal, the complex mol­ecules are linked by weak C—H⋯O inter­actions.

Specific Features of Technetium Mononuclear Octahedral Oxo Complexes: A Review

Abstract: The specific structural features of technetium mononuclear octahedral oxo complexes have been considered. The structures of d 2-Tc(V) mono- and dioxo complexes, d 2-Tc(V) pseudodioxo compounds (Tc(V) mono-oxo complexes with an additional multiply bonded RO− ligand), and d 0-Tc(VII) trioxo compounds are analyzed.

Di-μ-oxido-bis-({2,2'-[ethane-1,2-diylbis(nitrilo-methanylyl-idene)]diphenolato}titanium(IV)) chloro-form disolvate.

Abstract: In the title structure, [Ti2(C16H16N2O2)2O2]·2CHCl3, the Ti atom is coordinated in a distorted octa­hedral geometry by the O,N,N′,O′ donor set of the salalen ligand and by two μ2-oxide O atoms, which bridge two Ti(salalen) fragments into a centrosymmetric dimeric unit. In the central Ti2(μ2-O)2 fragment, the metal–oxygen distances are significantly different [1.7962 (19) and 1.9292 (19) A]. In the crystal, the chloro­form mol­ecule is anchored via an N—H⋯Cl and a bifurcated C—H⋯(O,O) hydrogen bond. Slipped π–π stacking [shortest C⋯C distance = 3.585 (4) A] and C—H⋯π inter­actions contribute to the coherence of the structure.

2-(1H-Imidazol-1-yl)-4-[3-(trifluoro-meth-yl)phen-yl]-1,3-thia-zole.

Abstract: The title compound, C13H8F3N3S, consists of three linked aromatic rings. The whole mol­ecule (except for the three F atoms) is planar to within 0.225 (2) A. In the crystal, adjacent mol­ecules are linked into chains along the ac diagonal by weak C—H⋯N inter­actions.

Complexing and ion selective properties of some acid type phosphoryl podands. The crystal and molecular structures of 1,5-bis(2-dihydroxyphosphoryl-4-ethylphenoxy)-3-oxapentane dihydrate [(HO)2(O)P(C6H3CH2CH3)(OCH2CH2)2O (C6H3CH2CH3)P(O)(OH)2] · 2H2O

Abstract: The synthesis of 1,5-bis(2-dihydroxyphosphoryl-4-ethylphenoxy)-3-oxapentane [(HO)2(O)P(C6H3CH2CH3)(OCH2CH2)2O(C6H3CH2CH3)P(O)(OH)2] (H4K2) and single crystal X-ray diffraction study of H4K2 · 2H2O (I) are described. The crystals are orthorhombic, a = 33.291(4) A, b = 8.9374(10) A, c = 8.1021(9) A, V = 2410.6(5) A3, Z = 4, space group Cmc21, R = 0.0484 for 2566 reflections with I > 2σ(I). In I, the molecules of H4K2 are hydrogen-bonded to two crystallographically independent H2O molecules to give neutral conglomerates H4K2 · 2H2O. The electroanalytical characteristics of poly(vinyl chloride) membranes based on H4K2 were tested. Cu2+ and Zn2+ complexes with H4K2 and Er3+, Nd3+, and complexes with H4K2, 1,5-bis[2-(dihydroxyphosphoryl-4-methoxy)phenoxy]-3-oxapentane, 1,5-bis[2-(dihydroxyphosphinyl)phenoxy]-3-oxapentane, and 1,8-bis[2-(dihydroxyphosphinyl)phenoxy]-3,6-dioxaoctane were prepared.

Coordination compounds of some d metals with nitrophenylhydrazone oxopyridine (pyrimidine) derivatives: Crystal and molecular structure of C10H9N5O6

Abstract: Twelve new d-metal complexes with 5-[(4-nitrophenyl)hydrazo]pyrimidine-2,4,6-trione (HL1) and 4-methyl-5-[4-nitrophenylhydrazo]-2,6-dioxo-1,2,5,6-tetrahydropyridine-3-carbonitryl (HL2) have been synthesized and separated out in the crystalline state. The crystal and molecular structures of HL1 have been solved by X-ray diffraction analysis. The organic molecule exists in the crystalline state as a planar hydrazo tautomer stabilized by intramolecular hydrogen bonds. Metal coordination is bidentate chelate. The acid-base equilibria and complexation of the ligands in solutions have been studied, and the complexation constants have been found.

(1SR,3RS,3aSR,6aRS)-Methyl 5-methyl-4,6-dioxo-3-[2-(trifluoro-meth-yl)phen-yl]octa-hydro-pyrrolo-[3,4-c]pyrrole-1-carboxyl-ate.

Abstract: In the title compound, C16H15F3N2O4, the relative stereochemistry of the four stereogenic C atoms has been determined. The carb­oxy­methyl and 2-(trifluoro­meth­yl)­phenyl substituents of the pyrrolidine cycle have a cis mutual arrangement. The five-membered saturated aza­cycle adopts an envelope conformation with the N atom occupying the flap position. In the crystal, adjacent mol­ecules are combined in centrosymmetric dimers by two weak N—H⋯O hydrogen bonds.