Search

A new triclinic polymorph of the title compound, [PdCl(2)(C(18)H(15)P)(2)], has two independent molecules in the unit cell, with the Pd atoms located on inversion centres. One molecule has an eclipsed conformation, whereas the second molecule adopts a gauche conformation. The molecules with a gauche conformation are involved in weak intermolecular C-H···Cl-Pd interactions with symmetry-related molecules. It is suggested that C-H···Cl-Pd interactions are mainly responsible for the existence of conformational differences, which contribute to the polymorph formation. In the crystal, there are layers of eclipsed and gauche molecules separated by normal van der Waals interactions.

The title 2:1 complex of 3-nitrophenol (MNP) and 4,4'-bipyridyl N,N'-dioxide (DPNO), 2C(6)H(5)NO(3) x C(10)H(8)N(2)O(2) or 2MNP.DPNO, crystallizes as a centrosymmetric three-component adduct with a dihedral angle of 59.40 (8) degrees between the planes of the benzene rings of MNP and DPNO (the DPNO moiety lies across a crystallographic inversion centre located at the mid-point of the C-C bond linking its aromatic rings). The complex owes its formation to O-H...O hydrogen bonds [O...O = 2.605 (3) A]. Molecules are linked by intermolecular C-H...O and C-H...N interactions forming R(2)(1)(6) and R(2)(2)(10) rings, and R(6)(6)(34) and R(4)(4)(26) macro-rings, all of which are aligned along the [1 01] direction, and R(2)(2)(10) and R(2)(1)(7) rings aligned along the [010] direction. The combination of chains of rings along the [1 01] and [010] directions generates the three-dimensional structure. A total of 27 systems containing the DNPO molecule and forming molecular complexes of an organic nature were analysed and compared with the structural characteristics of the dioxide reported here. The N-O distance [1.325 (2) A] depends not only on the interactions involving the O atom at the N-O group, but also on the structural ordering and additional three-dimensional interactions in the crystal structure. A density functional theory (DFT) optimized structure at the B3LYP/6-311G(d,p) level is compared with the molecular structure in the solid state.

Single crystals of the phenylcoumarin named mammeigin (or mammea A/AA cycle D) [systematic name: 5-hydroxy-8,8-dimethyl-6-(3-methylbutanoyl)-4-phenyl-2H,8H-pyrano[2,3-f]chromen-2-one], C25H24O5, were obtained in the course of a chemotaxonomic study of the Guttiferae family. Mammeigin was extracted from the fruits of Kilmeyera pumila. The structure reveals an infinite three-dimensional network stabilized by non-classical intermolecular hydrogen bonds.

The first structurally characterized alkali metal phosphonate, the title compound, [K2(C6H6O3P)2(C3H7NO)(H2O)]n, has a complex structure, with layers parallel to the crystallographic bc plane consisting of two crystallographically independent K atoms sandwiched between the three types of ligands present in the structure, viz. water molecules, dimethylformamide molecules and two crystallographically independent phenylphosphonate ligands. Six O atoms coordinate to one K atom and seven to the other. The interlayer distance is 15.327 (4) A. The K-O distances are in the range 2.739 (2)-2.932 (2) A for the seven-coordinate K atom and 2.650 (2)-2.821 (2) A for the six-coordinate K atom.

Pamidronate (3-ammonium-1-hydroxypropylidene-1,1-bisphosphonate) is used clinically in the treatment of diseases affecting bone tissue. In the salt zinc pamidronate dihydrate, Zn(2+).2C(3)H(10)NO(7)P(2)(-).2H(2)O, pamidronate is a zwitterion with an overall charge of -1. The carbon chain adopts a trans conformation, separating maximally the positively charged N atom from the negative phosphonate groups. The Zn(2+) ion lies on an inversion center and is surrounded by a sixfold coordination sphere provided by two bidentate chelating zwitterions and two water molecules. The bidentate O.Zn.O bond angle is 92.70 (7) degrees, while the O.O bite distance is 3.018 (3) A.

Single crystals of methyl-p-aminobenzoate (MAB), C(8)H(9)NO(2), were obtained during the synthesis of 4-amino-N'-(5-nitro-2-thienylmethylene)benzohydrazide. A P2(1)/c polymorph [a = 8.5969 (4) A, b = 5.6053 (2) A, c = 15.5397 (7) A and beta = 96.172 (2) degrees ] of MAB was found and the intra- and intermolecular geometries were compared with those of the previously known C2/c structure [a = 16.242 (2) A, b = 8.113 (2) A, c = 12.724 (2) A and beta = 69.17 (1) degrees; Xianti (1983). Jiegou Huaxue, 2, 219-221].

The preparation and structures of caesium lithium sulfate, Cs(1.15)Li(2.85)(SO(4))(2), and caesium lithium rubidium sulfate, Cs(0.90)Li(2.88)Rb(0.22)(SO(4))(2), are described and discussed in the context of simple and double sulfate polymorphism. The latter structure is related to the former through the substitution of Rb for Cs. In both crystals, the sulfate ions occupy two non-equivalent sites, but the ions are disordered in Cs(1.15)Li(2.85)(SO(4))(2).