2-Chloro-8-methyl-3-[(pyrimidin-4-yloxy)methyl]quinoline

In the title compound, C15H12ClN3O, the quinoline ring system is essentially planar, with a maximum deviation of 0.017 (1) angstrom. The crystal packing is stabilized by pi-pi stacking interactions between the quinoline rings of adjacent molecule, with a centroid-centroid distance of 3.5913 (8) angstrom. Aweak C-H center dot center dot center dot pi contact is also observed between molecules.

5-(4-Chlorophenyl)-3-(2,4-dimethylthiazol-5-yl)-1,2,4-triazolo[3,4-a]isoquinoline

In the title molecule, C21H15ClN4S, the triazoloisoquinoline ring system is approximately planar, with an r.m.s. deviation of 0.054 (2) angstrom and a maximum deviation of 0.098 (2) angstrom from the mean plane for the triazole ring C atom that is bonded to the thiazole ring. The thiazole and benzene rings are twisted by 66.36 (7) and 56.32 (7)degrees respectively, with respect to the mean plane of the triazoloisoquinoline ring system. In the crystal structure, molecules are linked by intermolecular C-H center dot center dot center dot N interactions along the a axis. The molecular conformation is stabilized by a weak intramolecular pi-pi interaction involving the thiazole and benzene rings, with a centroid-centroid distance of 3.6546 (11) angstrom . In addition, two other intermolecular pi-pi stacking interactions are observed, between the triazole and benzene rings and between the dihydropyridine and benzene rings [centroid-centroid distances = 3.6489 (11) and 3.5967 (10) angstrom, respectively].

The heat kernel on AdS(3) and its applications

We derive the heat kernel for arbitrary tensor fields on S-3 and (Euclidean) AdS(3) using a group theoretic approach. We use these results to also obtain the heat kernel on certain quotients of these spaces. In particular, we give a simple, explicit expression for the one loop determinant for a field of arbitrary spin s in thermal AdS(3). We apply this to the calculation of the one loop partition function of N = 1 supergravity on AdS(3). We find that the answer factorizes into left- and right-moving super Virasoro characters built on the SL(2, C) invariant vacuum, as argued by Maloney and Witten on general grounds.

Quinone Studies—II : Reduction potentials of some 3-substituted phenanthrene quinones

Polarographic reduction potentials of seven 3-substituted phenanthrenequinones have been determined in aqueous dioxan and aqueous ethanol under different pH conditions. The substituent effects on the reduction potentials could be correlated with the Hammett σ- constants (correlation coefficients> 0·995). The possibility of using reduction potentials as an accurate measure of resonance energy has been pointed out.

New family of thallium cuprate superconductors not containing calcium or barium: TlSrn+1−xLnxCunO2n+3+δ (Ln=La, Pr, or Nd)

The first two members of the new TlSrn+1−xLnxCunO2n+3+δ (Ln=La, Pr, or Nd) series of superconducting cuprates possessing 1021 and 1122 type structures are described. The n=1 (1021) members with Tcs around 40 K have electrons or holes as the majority charge carriers depending on x. The n=2 (1122) cuprate (Ln=Pr or Nd) shows a Tc in the 80–90 K range.

Enzyme catalysed non-oxidative decarboxylation of aromatic acids II. Identification of active site residues of 2,3-dihydroxybenzoic acid decarboxylase from Aspergillus niger

In order to understand the mechanism of decarboxylation by 2,3-dihydroxybenzoic acid decarboxylase, chemical modification studies were carried out. Specific modification of the amino acid residues with diethylpyrocarbonate, N-bromosuccinimide and N-ethylmaleiimide revealed that at least one residue each of histidine, tryptophan and cysteine were essential for the activity. Various substrate analogs which were potential inhibitors significantly protected the enzyme against inactivation. The modification of residues at low concentration of the reagents and the protection experiments suggested that these amino acid residues might be present at the active site. Studies also suggested that the carboxyl and ortho-hydroxyl groups of the substrate are essential for interaction with the enzyme.

(2-Chloro-8-methylquinolin-3-yl)methanol

The molecule of title compound, C11H10ClNO, is close to being planar (r.m.s deviation for the non-H atoms = 0.017 angstrom). In the crystal, molecules interact by way of O-H center dot center dot center dot O hydrogen bonds, generating C(2) chains propagating in [010]. The crystal structure is consolidated by C-H center dot center dot center dot pi interactions and aromatic pi-pi stacking interactions [centroid-centroid distance = 3.661 (2) angstrom].

(2-Chloro-6-methylquinolin-3-yl)methanol

The title compound, C11H10ClNO, is close to being planar (r.m.s deviation for the non-H atoms = 0.026 angstrom). In the crystal,molecules are linked by O-H center dot center dot center dot O hydrogen bonds, generating C(2) chains, and weak C-H center dot center dot center dot pi interactions and aromatic pi-pi stacking interactions [centroid-centroid distance = 3.713 (3) angstrom] help to consolidate the sturcture.

3-[(2-Chloro-6-methylquinolin-3-yl)methyl]quinazolin-4(3H)-one

In the title molecule, C19H14ClN3O, the quinoline and quinazoline ring systems form a dihedral angle of 80.75 (4)degrees. In the crystal, the molecules are linked by pairs of C-H center dot center dot center dot N hydrogen bonds into centrosymmetric dimers, generating R-2(2)(6) ring motifs. The structure is further stabilized by C-H center dot center dot center dot pi interactions and pi-pi stacking interactions [centroid-centroid distances = 3.7869 (8) and 3.8490 (8) angstrom].

(Z)-2-(2-Isopropyl-5-methylphenoxy)-N`-(2-oxoindolin-3-ylidene)acetohydrazide

In the title Mannich base, C20H21N3O3, an isatin derivative of thymol the O-CH2-C(=O)-N(H)-N fragment connecting the aromatic and fused-ring systems is approximately planar, with the N-N single bond in a Zmconfiguration. The amino H atom of this N-N fragment is intramolecularly hydrogen bonded to the carbonyl O atom of the indolinone fused ring as well as to the phenoxy O atom of the aromat ring. The amino H atom of the indoline fused ring forms a hydrogen bond with the double-bond O atom of an adjacent molecule, this hydrogen bond giving rise to a linear chain motif.

Am unexpected entry into the silver(I) chemistry of diphosphazane ligands: Crystal and molecular structures of [Ag{Ph2PN(Pr-i)PPh2}(CF3SO3)](2), [Ag{Ph2PN(Pr-i)PPh(OC6H3Me2-2,6)}(2)]PF6, and [Ag-3(mu-Cl)(2){Ph2PN(R)PPh2}(3)]PF6 (R = H, Pr-i)

Mononuclear, binuclear and trinuclear silver(l) complexes were obtained unexpectedly while probing the reactivity of diphosphazane ligands of the type X2PN(Pr-i)PXY towards the ruthenium-based precursor Ru(bipy)(2)Cl-2 center dot 2H(2)O, in the presence of a silver salt as a chloride scavenger. Subsequently, the reactions of AgX [X = Cl, NO3 or CF3SO3] with Ph2PN(R)PPh(Y) [R = H, Y = Ph; R = Pr-i, Y = Ph or OC6H3Me2-2,6] in a 1: 1 or 1:2 molar ratio have been investigated. Mononuclear or binuclear Ag(I) complexes containing either chelating or bridging diphosphazane ligands are obtained. Trinuclear silver(l) complexes are accessible by the treatment of diphosphazane ligands, Ph2PN(R)PPh2 [R = H, Pr-i] with AgCl using piperidine as the solvent. In the presence of a suitable chloride donor species, the mononuclear and binuclear complexes of Ph2PN(Pr-i)PPh2 are transformed slowly to the trinuclear complex [Ag-3(mu-Cl)(2){Ph2PN(Pr-i)PPh2}(3)]X, over a period 20 h. The structures of representative complexes have been confirmed by X-ray crystallography and the salient structural features are discussed