In the title compound, C(6)H(5)Cl(3)N(+)·ClO(4) (-)·C(12)H(24)O(6), the perchlorate anion is disordered over two orientations in a 0.666 (17):0.334 (17) ratio. The ammonium group of the organic cation inserts into the crown ether ring and forms three bifurcated N-H⋯(O,O) hydrogen bonds to generate a supra-molecular complex. The macrocycle has approximate D(3d) local symmetry.

The Sn, Cl and water O atoms of the title compound, [Sn(2)(CH(3))(4)Cl(4)(H(2)O)(2)]·C(10)H(20)O(5), lie on a special position of 2 site symmetry. The Sn(IV) atom shows cis-C(2)SnCl(2)O trigonal-bipyramidal coordination [C-Sn-C = 157.0 (1)°]; however, two [Me(2)SnCl(2)(H(2)O)] units are linked by a tin-chlorine bridge [Sn←Cl = 3.247 (1) Å] across a center of inversion, generating a dinuclear sp...

The new compound [K–(12C4)2]2[K–12C4]2[Sn9]·4en (1), where 12C4 is 12-crown-4 polyether, was crystallized from an ethylenediamine solution of an intermetallic precursor with nominal composition K4Li2Sn8. The structure of the compound (orthorhombic, Cmca, a = 21.763(4), b = 16.030(3), c = 51.85(1) Å, Z = 8) contains isolated deltahedral clusters of [Sn9]4−. The clusters are of Cs symmetry and ar...

The asymmetric unit of the title compound, H(3)O(+)·ClO(4) (-)·C(20)H(24)O(6), contains two mol-ecules/ions of each species. Both dibenzo-18-crown-6 mol-ecules have a complexed hydro-nium ion inside their cavity with O-H⋯O and O-H⋯(O,O) links between the two species. The associated perchlorate anions also accept O-H⋯O hydrogen bonds from the hydro-nium ion. Both crown ether mol-ecules are prese...

The title compound, C24H29NO4, is the product of a Petrenko-Kritchenko condensation of 1,5-bis-(2-formyl-phen-oxy)-3-oxa-pentane, pentan-3-one and methyl-ammonium acetate in ethanol. The mol-ecule has mirror symmetry. The aza-14-crown-3 ether ring adopts a bowl conformation stabilized by a weak intra-molecular C-H⋯O hydrogen bond. The conformation of the C-O-C-C-O-C-C-O-C polyether chain is t-g...

OBJECTIVES To determine the frequency, variability, sexual dimorphism and bilateral symmetry of fourteen dental crown traits in the deciduous and permanent dentition of 60 dental models (35 women and 25 men) obtained from a native, indigenous group of Nasa school children of the Musse Ukue group in the municipality of Morales, Department of Cauca, Colombia. METHODS This is a quantitative, des...

The K antigenic capsular polysaccharide forms a structural layer, the capsule, on the surfaces of Escherichia coli cells. The capsule provides an important protective covering that helps protect encapsulated bacteria from host immune defenses. The assembly and translocation of the capsule requires proteins in the inner and outer membranes. The inner membrane protein Wzc is a tyrosine autokinase...

The transition between 190 and 200 K in [Ni(H(2)O)(6)](NO(3))(2)·(15-crown-5)·H(2)O has been followed by determining the structure at 22 temperatures in the range 90-273 K. The structural change is a zone-boundary transition with a critical point at (½, 0, ½) in the Brillouin zone of the high-temperature phase; both phases have space-group symmetry P2(1) but the volume of the unit cell is halve...