Lambda-[1,4,7,10-tetrakis[(S)-2-hydroxypropyl-kappaO]-1,4,7,10-tetraazacyclododecane-kappa4N]cadmium(II) bis(2,4,6-trinitrophenolate) acetonitrile solvate.

Crystallization of [Cd(S-thpc12)](ClO(4))(2) x H(2)O [S-thpc12 is 1,4,7,10-tetrakis[(S)-2-hydroxypropyl]-1,4,7,10-tetraazacyclododecane] in the presence of two equivalents of sodium picrate monohydrate (sodium 2,4,6-trinitrophenolate monohydrate) diastereoselectively produces a neutral receptor complex, viz. the title compound, lambda-[Cd(C(20)H(44)N(4)O(4))](C(6)H(2)N(3)O(7))(2) x CH(3)CN. In this complex, two picrate anions hydrogen bond, via their phenolate moieties, to the pendant hydroxyl groups of the receptor which, together with the four N atoms, themselves bond to Cd(II) in an approximately cubic arrangement.

On the structure of aragonite -- Lawrence Bragg revisited.

The structure of aragonite was first determined by Lawrence Bragg in 1924 in what is the now standard space-group setting Pnma (No. 62). Subsequent studies have all taken his structure as their starting points, despite Bragg's own stated doubts and some earlier etching studies which indicated that the underlying symmetry may really be polar.

Metal ion-dependent molecular inclusion chemistry: inclusion of aromatic anions by coordinated 1,4,7,10-tetrakis((S)-2-hydroxy-3-phenoxypropyl)-1,4,7,10-tetraazacyclododecane.

The ability of the pendant donor macrocyclic ligand 1,4,7,10-tetrakis((S)-2-hydroxy-3-phenoxypropyl)-1,4,7,10-tetraaza- cyclododecane((S)-thphpc12) (or [Cd((S)-thphpc12)](2+)) to act as a metal ion-dependent receptor for aromatic anions has been investigated in solution and in the solid state. [Cd((S)-thphpc12)](2+) adopts a stable conical conformation with a large hydrophobic cavity, which has been shown to contain, via complementary multiple hydrogen bonding, p-nitrophenolate, aromatic carboxylates, p-toluenesulfonate, certain aromatic amino acid anions, phenoxyacetate, and acetate. In the case of p-nitrophenolate only, one or two anions can be contained within the receptor cavity.

Metal Ion Dependent Molecular Inclusion Chemistry: Inclusion of p-Toluenesulfonate and p-Nitrophenolate within the Structure of Coordinated 1,4,7,10-Tetrakis((S)-2-hydroxy-3-phenoxypropyl)-1,4,7,10-tetraazacyclododecane.

The pendant donor macrocyclic ligand 1,4,7,10-tetrakis((S)-2-hydroxy-3-phenoxypropyl)-1,4,7,10-tetraazacyclododecane ((S)-thphpc12) has been synthesized in quantitative yield from cyclen (1,4,7,10-tetraazacyclododecane) and (2S)-(+)-3-phenoxy-1,2-epoxypropane. An X-ray diffraction study supports the result of molecular orbital calculations in showing that complexation with hydrated cadmium(II) diperchlorate produces an approximately square-antiprismatic complex in which the metal ion is located between a plane containing the four nitrogen atoms and a plane containing the four oxygen atoms. As a consequence of this the four phenoxymethyl moieties, each attached to one of the four N-O chelate rings, juxtapose to form a substantial empty cavity allowing the complex to act as a molecular receptor.

Gold(I)-Purine Interactions: Synthesis and Characterization of Cyclic and Open Chain Polynuclear Gold(I) Complexes Containing Xanthine Derivatives and Bis(phosphine) as Bridging Ligands. Crystal Structures of [Au(2)(&mgr;-HX)(&mgr;-dmpe)].3H(2)O and [Au(2)(&mgr;-TT)(&mgr;-dmpe)].H(2)O (H(3)X = Xanthine; H(2)TT = 8-Mercaptotheophylline).

The reaction of [(AuBr)(2)(&mgr;-PR(2)P(CH(2))(n)()PR(2))] (where R = CH(3) for n = 1; R = Ph for n = 1, 3, 4) with N-alkylxanthine and thioxanthine derivatives, containing two ionizable protons in close positions, yields, under basic conditions, neutral heterobridged dinuclear gold(I) ring complexes [Au(&mgr;-L)(2)(&mgr;-PR(2)P(CH(2))(n)()PR(2))], which have been investigated by means of (1)H- and (31)P-NMR and FAB spectroscopies. Crystal structures of two of these complexes are reported. [Au(2)(&mgr;-HX)(&mgr;-dmpe)].