Thermal Analysis of Hexachloroplumbate and Chlorides Containing Complex Divalent Lead 2,2'-bipyridine Cations

Lead(II) 2,2'-bipyridine hexachloroplumba tetetrahydrate was synthesized and investigated by DTA, TG and DTG. IR spectroscopy and other methods enabled the identification of some of the decomposition products. Comparative studies on the corresponding chlorides: [Pb(bipy)]Cl₂ and [Pb(bipy)₃]Cl₂, which can be considered as precursors of the hexachloroplumbate, were also undertaken. X-ray measurements enabled the tentative determination of the crystal structure of [Pb(bipy)]Cl₂. Hexachloroplumbate decomposes with the liberation of chlorine, water and organic ligands, and the process is accompanied by the simultaneous transition of Pb(IV)→Pb(II). Chlorides release only ligands upon heating. Residues comprised always PbCl₂. This revised version was published online in August 2006 with corrections to the Cover Date.     

Lower Rim Substituted p-tert-Butyl Calix[4]arenes (V). Synthesis of New 5,11,17,22-tetrakis-p-tert-Butyl-25,27-bis(methoxy)- 26,28-bis(dialkoxyphosphorylmethoxy)calix[4]arenes and Cation Complexation Studies in Ion-Selective Membrane Electrodes

The synthesis and characterization of the lower rim bis-phosphorylatedtetrakis-p-tert-butyl-25,27-bis(methoxy)calix[4]arenas(compounds 2–4) is presented. The studied compounds were examined as ionophores in ion-selective membrane electrodes, showing selectivity for rubidium, potassium, and for the large and flat guanidinium cations (G⁺). The correlation wasstudied between the stereochemical structure of the ligands andpotentiometrically determined ion-selectivity. Complex formationconstants in the PVC/BEHS (bis(ethyl)hexyl sebacate) membranes weredetermined. The crystal and molecular structures of compound 4 have been determined by single crystal X-ray diffraction study.     

9‐(2,6‐Dichloro­phen­oxycarbonyl)‐10‐methyl­acridinium trifluoro­methane­sulfonate and its precursor 2,6‐dichloro­phenyl acridine‐9‐carboxyl­ate

The title compounds, C₂₁H₁₄Cl₂NO₂⁺·CF₃O₃S⁻, (I), and C₂₀H₁₁Cl₂NO₂, (II), form triclinic crystals. Adjacent cations of (I) are oriented either parallel or antiparallel; in the latter case, they are related by a centre of symmetry. Together with the CF₃SO₃⁻ anions, the antiparallel‐oriented cations of (I) form layers in which the mol­ecules are linked via a network of C—H·O and π–π inter­actions (between the benzene rings). These layers, in turn, are linked via a network of multidirectional π–π inter­actions between the acridine rings, and the whole lattice is stabilized by electrostatic inter­actions between ions. Adjacent mol­ecules of (II) are oriented either parallel or antiparallel; in the latter case, they are related by a centre of symmetry. Parallel‐oriented mol­ecules are arranged in chains stabilized via C—H·Cl inter­actions. These chains are oriented either parallel or antiparallel and are stabilized, in the latter case, via multidirectional π–π inter­actions and more generally via dispersive inter­actions. Acridine and independent benzene moieties lie parallel in the lattices of (I) and (II), and are mutually oriented at an angle of 33.4 (2)° in (I) and 9.3 (2)° in (II).     

10‐Methyl‐ and 9,10‐dimethyl­acridinium methyl sulfate

The title compounds, C₁₄H₁₂N⁺·CH₃O₄S^?, (I), and C₁₅H₁₄N⁺·CH₃O₄S^?, (II), respectively, crystallize with the planar 10‐methylacridinium or 9,10‐di­methyl­acridinium cations arranged in layers, parallel to the twofold axis in (I) and perpendicular to the 2₁ axis in (II). Adjacent cations in both compounds are packed in a `head‐to‐tail' manner. The methyl sulfate anion only exhibits planar symmetry in (II). The cations and anions are linked through C—H?O interactions involving three O atoms of the anion, six acridine H atoms and the CH₃ group on the N atom in (I), and the four O atoms of the anion, three acridine H atoms and the carbon‐bound CH₃ group in (II). The methyl sulfate anions are oriented differently in the two compounds relative to the cations, being nearly perpendicular in (I) but parallel in (II). Electrostatic interaction between the ions and the network of C—H?O interactions leads to relatively compact crystal lattices in both structures.     

2‐Methylphenyl 2‐methoxyacridine‐9‐carboxylate

The title compound, C₂₂H₁₇NO₃, crystallizes in the monoclinic space group P2₁/c with four molecules per unit cell. The mol­ecules are arranged in centrosymmetric pairs, joined via the C and attached H atoms in the meta position relative to the methoxy group. These pairs are bonded in the crystalline phase as a result of non‐specific dispersive interactions, and through a network of C—H?O interactions involving the non‐bonded O atom of the carboxy group and, to some extent, the O atom of the methoxy group. The methoxy substituent lies in the plane of the almost planar acridine moiety and is directed towards the phenyl ester group. The phenyl ester group itself is twisted by 35.9 (5)° relative to the mean plane of the acridine moiety.     

Synthesis and Structural Studies of New (Triphenylphosphine)(trialkoxysilanethiolato)gold(I) Complexes

Compounds of general formula Au{SSi(OR)₃}(PPh₃), R = Prⁱ ( 1 ), Bu^s ( 2 ) or Bu^t ( 3 ), have been obtained by reaction of AuCl(PPh₃) with triethylammonium salts of respective silanethiols, (RO)₃SiSH. Molecular and crystal structures of 1 , 2 , and 3 have been determined by the single crystal X‐ray structural analysis. Compounds 1 and 2 are the first structurally characterized metal derivatives of hydrolytically unstable trialkoxysilanethiols (PrⁱO)₃SiSH and (Bu^sO)₃SiSH.     

Contributions to the Chemistry of Silicon—Sulphur Compounds. 66. Synthesis,crystal and molecular structure of bis(tri-tert-butoxysilanethiolato)(acetonitrile)cobalt(II)[(t-C4H9O)3SiS]2Co(NCCH3)

The title compound [(t-C₄H₉O)₃SiS]₂Co(NCCH₃)] 1 was obtained by reaction of anhydrous cobalt(II) chloride with tri-tert-butoxysilanethiol and triethylamine in acetonitrile as a solvent. The compound crystallizes as deep-blue orthorhombic plates with a = 17.779(4), b = 45.363(9), c = 9.096(2) Å, space group Fdd2 and Z = 8. The structure was solved by Patterson synthesis and refined to the R value of 0.0343. The crystal consists of mononuclear complexes in which the cobalt atom is five-fold coordinated to two sulphurs, two oxygens and one nitrogen in a distorted trigonal bipyramidal arrangement. The relevant bond distances and angles are: Co? S, 2.2680(7); Co? N, 2.065(4); Co? O1, 2.283(2); S? Si, 2.0666(8) Å; S? Co? S′, 119.14(4); N? Co? S, 120.43(2); O1? Co? O1′, 178.81(10)°.     

2‐(N,N‐Diphenylamino)benzoic acid

Shaped like a distorted propeller, mol­ecules of the title compound, C₁₉H₁₅NO₂, form centrosymmetric dimers in the crystalline phase in which the carboxy groups are linked through two hydrogen bonds. These dimers are arranged in columns held together via dispersive interactions between the phenyl moieties. The N atom and the three surrounding C atoms lie almost in the same plane, which implies that the lone electron pair of the N atom is involved in conjugation with the π systems of the phenyl fragments.