Complexes of copper(II) with some new thiocarbamide derivatives

Summary A new series of thiocarbamides was prepared by the reaction of benzoylisothiocyanate with various amines namely 2-aminopyridine (H₂L_I), 3-aminopyridine (H₂L_II), 2,3-diaminopyridine (H₂L_III), 2,6-diaminopyridine (H₂L_IV), o-phenylene diamine (H₂L_V), p-phenylenediamine (H₂L_VI) and ethylene diamine (H₂L_VII). The copper(II) complexes of these ligands were isolated and have been characterized by elemental analyses, molar conductivities, magnetic moments and spectral (visible, i.r.) measurements. I.r. spectra show that the ligands behave as dianionic or neutral tetradentates or as monoanionic or neutral bidentates. The [Cu(HL_I)Cl]₂ and Cu(H₂L_IV)Cl₂ complexes are diamagnetic and the other complexes have normal magnetic moment at room temperature. Electronic spectral analyses show that Cu₂(L_IV)Ac₂ is planar and the other complexes are tetragonally distorted octahedral. All the complexes are non-electrolytes.     

Heterometallic lanthanide group 12 metal iodides

Neodymium tri-iodide reacts with Group 12 metal (M; M = Zn, Cd, Hg) iodides to form heterometallic compounds. These Lewis acidic M cleave Nd-I bonds to give either ionic ([(THF)(5)NdI(2)][MI(3)THF]; M = Zn, Cd) or charge-neutral [(THF)(5)NdI(micro(2)I)HgI(3)] compounds. Differences in structure are interpreted primarily in terms of M-L bond strengths, rather than Nd-L bond strengths. Experiments with Yb indicate that if there is any excess iodide present in these syntheses then the most readily isolated product is a triiodide salt, i.e., [(THF)(5)YbI(2)][I(3)]. In conventional solvents the presence of Lewis acid is not required for iodide displacement-from pyridine, "YbI(3)" crystallizes as [(py)(5)YbI(2)][I]. These compounds are potentially useful as heterometallic sources of lanthanide-doped iodide matrixes, they illustrate the ease with which iodides are displaced from lanthanide coordination spheres, and they underscore the complexity associated with using lanthanide iodides as Lewis acid catalysts.     

Pyridine-1-oxide complexes of lanthanide iodides

Pyridine-1-oxide complexes of lanthanide iodides of the formulaLn(PyO)₈I₃ whereLn=La, Pr, Nd, Tb, Dy, Er, and Yb have been prepared and characterised by analyses, molecular weight, conductance, infrared and proton NMR data. Proton NMR and IR data have shown the coordination of the ligand to the metal through the oxygen atom of the N?O group. NMR data have been interpreted in terms of a distorted square antiprismatic geometry in solution.     

Structural characteristics of some diphenyl oxide derivatives

Conclusions Data are given which question the reliability of the communication concerning the preparation of two conformational isomers of p-bromodiphenyl ether.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 143–145.     

Structural peculiarities of some diphenyl ether derivatives

Conclusions On bromination of diphenyl ether the first bromine atom enters into the hydrocarbon ring, and the second bromine atom enters into the ethereal ring. The same principle was found for the chloromethylation of diphenyl ether.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 142–144, January, 1969.     

Structure-stability relationships of some meta- and para-hydrazopyrazolone derivatives with trivalent lanthanide ions

Acid dissociation constants (pK^H) of a series of 10 compounds (I to X) of substituted 5-pyrazolone dyes have been determined potentiometrically in 75% (v/v) dioxane-water at 30 °C and <0.1 M ionic strength. The stability constants of their 1:1 and 1:2 chelates with 13 lanthanide ions Ln(III) have also been determined. The effect of substituents on the hydrazo moiety of the ligand is discussed. Data are correlated and the results are used to explain the stabilization of such chelates by dative π bonding between Ln(III) and the ligand.     

Structural determinations of some chloroazepine-2,5-diones using a lanthanide shift reagent

The use of a lanthanide shift reagent, Eu(fod)₃, to aid in the structural assignments of some chloroazepine-2,5-diones is described. The chloroazepine-2,5-diones, synthesized via the Schmidt reactions of chloro-1,4-benzoquinones, could not readily have their structures assigned by other spectroscopic methods. Correlations of plotted lanthanide induced shifts in pmr studies demonstrated that there was a large positional dependence on the magnitude of induced shifts. The large difference in the magnitude of induced shifts made it possible to assign protons and methyl substituents to specific positions on the azepine ring, thus assigning the structure of the compound.     

Structural features for fluorescing present in methoxycoumarin derivatives

Structural features of fluorescent methoxycoumarins were examined from the viewpoint of substituent effect and ring structure in connection with intramolecular charge-transfer (ICT). The fluorescence of methoxycoumarins depended primarily upon the ICT from a C6-electron-donating group to the substituents at the C3-position of the coumarin ring. Furthermore, the presence of a lactone ring itself, including a carbonyl group, cyclic ether oxygen and ethylenic bond as partial ring structures, was found to be essential for fluorescing in methoxycoumarins according to the fluorescent behaviors of chemically deformed model compounds.     

The structure of some benzylideneamino-pyridinium iodides

The UV, IR, and PMR spectra of a number of m- and p-substituted N-(benzylideneamino)-pyridinium iodides confirm the structure of hydrazonium compounds proposed for them previously. On the basis of physicochemical data, a hypothesis has been put forward of the participation of the pyridinium ring in an intramolecular interaction of the conjugation type. Charge-transfer bands are observed in the UV spectra of some of these compounds.Communication XXXVIII of the series Hydrazones, for Communication XXXVII, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1219–1223, September, 1973.     

The luminescence of some lanthanide decatungstates

Luminescence of Na₉LnW₁₀O₃₆ · 18H₂O (Ln = Sm, Tb, Dy) and K₉EuW₁₀O₃₆ · 18H₂O is reported. Low efficiency of the Tb³⁺ compound is ascribed to non-radiative loss via a charge-transfer (Tb⁴⁺-W⁵⁺) state. The Sm³⁺ and Dy³⁺ compounds have only medium luminescence efficiency due to cross relaxation between lanthanide ions. The Eu³⁺ compound demonstrates again the sensitivity of Eu³⁺ luminescence to small changes.     

Thermodynamic properties of some lanthanide chlorides

The heat capacities of the lanthanide chlorides NdCl₂, SmCl₂, EuCl₂, DyCl₂, TmCl₂, YbCl₂, DyCl₃, YbCl₃ and LuCl₃ were measured at 10–320 K with an adiabatic microcalorimeter.Standard thermodynamic properties were calculated from the experimental results.The heat capacities of these chlorides are composed of the lattice heat capacity and an additional contribution caused by the thermal population of the low-lying Stark electronic levels (Schottky anomaly). The Schottky heat capacity was estimated as the difference between the experimentalC _p values for the isostructural paramagnetic and diamagnetic chlorides. Experimental Schottky contributions were found to be in good agreement with those calculated for SmCl₂, TmCl₂ and YbCl₃ via a general model of the main-term Stark splitting of the respective ions in the orthorhombic and monoclinic crystal fields.

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Zusammenfassung Die Wärmekapazitäten von NdCl₂, SmCl₂, EuCl₂, DyCl₂, TmCl₂, DyCl₃, YbCl₃ und LuCl₃ wurden im Temperaturbereich 10–320 K mit einem adiabatischen Mikrokalorimeter gemessen. Aus den Ergebnissen wurden die thermodynamischen Standardwerte berechnet. Die Wärmekapazität dieser Chloride setzt sich zusammen aus der Gitter-Wärmekapazität und einem Beitrag, infolge der thermischen Besetzung der niedrig-liegenden Stark-Niveaus (Schottky-Anomalie). Die Schottky-Wärmekapazität wurde als Differenz zwischen experimentellenC _p -Werten isostruktureller para- und diamagnetischer Chloride geschätzt. Die experimentell gefundenen Schottky-Beiträge stimmen gut überein mit den Werten, die für SmCl₂, TmCl₂ und YbCl₃ nach einem verallgemeinerten Modell der Stark-Aufspaltung der Hauptterme der betreffenden Ionen im orthorhombischen bzw. monoklinen Kristallfeld berechnet wurden.

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10–320 , , , , , , . . , ( ). . SmCl₂, TmCl₂ YbCl₃ .

     

Conformational studies of some 2-phenylpropyl derivatives by NMR spectroscopy and use of lanthanide shift reagents

The conformational distribution of CH₃CH(Ph)CH₂X (X = OH, OCH₃, NH₂ Cl) has been studied by NMR and IR spectroscopy. The results are interpreted in favour of the conformers with methoxy- or chloro-groups anti to the phenyl group, but the amino group anti to the methyl group. For the alcohol both forms are about equally populated. It is suggested that intra-molecular hydrogen bonding might be affecting the conformational equilibria when X = OH, NH₂.     

Structural studies on some 1,3,5,7-tetraaza- and 1,3,5-triazaadamantane derivatives

¹H and ¹³C NMR data are reported for hexamethylenetetramine (hexamine), 7-nitro-1,3,5-triazaadamantane and some of their quaternary derivatives. INDO molecular orbital calculations have been performed on these molecules to aid the interpretation of their spectra.     

The cross coupling of some primary fluorochlorocarbon iodides

1,2-Dichloroiodotrifluoroethane reacts with zinc to form 1,2,3,4-tetrachlorohexafluorobutane and, by a coupling reaction with it, 1,2,3,5,6-pentachlorononafluorohexane. The latter compound was also synthesized from cross-coupling of CF₂ClCFClI and CF₂ClCFClCF₂CFClI. Heptafluorobutyl iodide and CF₂ClCFClCFClI did not cross couple     

Tandem reactions catalyzed by lanthanide iodides. Part 2: Tandem iminoaldol-enolisation reactions

Samarium diiodide is a catalyst for the reaction of cyclic and acyclic tert-butyldimethylsilyl enoxysilanes with chelating imines. Reaction products are isolated as β-aminoenoxysilanes instead of β-aminoketones as previously observed with the corresponding trimethylsilyl enoxysilanes. Several mechanistic pathways are discussed.     

Innovative synthetical and structural features of new aryltellurenyl iodides

The syntheses and the structural characterization of the compounds [(mes)₂Te–Te(I)mes], (PyH)[mesTeI₃(I₃)] (mes = mesityl = 2,4,6-trimethylphenyl; Py = pyridine), (PyH)₃[dmephTeI₂(I₂)]₂(I₃) (dmeph = 2,6-dimethylphenyl), (PyH)₂[RTeI₄]₂·(CH₃)CO(CH₃)·C₆H₅CH₃ (R = p-tert-butylphenyl) and (PyH)₂[PhTeI₄]₂ (Ph = phenyl) are presented. Some earlier analog preparations are compared and the influence of ortho substituents in the aryl group on the oxidation state of tellurium is discussed, as well as the observed conditions for the formation of poly-iodides chains.     

1H NMR separation of epimeric mixtures by lanthanide shift reagents: Analysis of some isoxazolidine derivatives

Epimeric mixtures of isoxazolidine derivatives were investigated by ¹H NMR spectra obtained in the presence of lanthanide shift reagents. The NMR signals of all the components contained in a mixture of 2,3-diphenyl-5-carboxymethylisoxazolidines were identified and the LISCA computer program enabled the stereochemistry of the different isomers to be established.     

Structural features of copper(II) and lanthanide(III) tartratogermanate(IV) complexes

Four heterometallic tartratogermanate complexes, namely [Cu₂Ge₂(Tart)₃(H₂O)₁₀] _n · 3nH₂O and (H₃O)[LnGe₂(Tart)₃(H₂O)₆] · nH₂O (Ln³⁺ = Gd, n = 3.5; Tm, n = 3; Yb, n = 3), have been prepared via the reaction between germanium tetrachloride and D-tartaric acid (H₄Tart) in aqueous acetic acid. All complexes contain {Ge₂(Tart)₃} _n ^4n- polymer chains. The Cu²⁺ and Ln³⁺ atoms coordinate only Tart carbonyl oxygen atoms.     

Structural studies on some 1,3,5,7-tetraazabicyclo-[3.3.1]-nonane derivatives

From a study of the ¹H NMR spectra of a number of 3,7-disubstituted derivatives of 1,3,5,7-tetraazabicycio - [3.3.1] - nonane it is concluded that these molecules exist in either chair-chair or flattened chair-chair conformations. The derivatives containing COCH₃ and NO substitutents have room temperature spectra consistent with restricted rotation about their NC and NN bonds respectively. High temperature spectra reveal an activation energy, for the rotational barrier of the NC bond in the diacetyl derivative, of 23±2K.Cal/mol.