Linking solution chemistry to crystal nucleation: the case of tetrolic acid.

The application of FTIR spectroscopy to concentrated solutions of tetrolic acid shows, for the first time, a direct relationship between molecular self association in solution and H-bonded motifs in the subsequently crystallised solid phases.

1,2-Bis(N-fluoro-p-toluenesulfonamido)ethane chloroform solvate.

The title compound, N,N'-difluoro-N,N'-ethylenedi-p-toluenesulfonamide, C(16)H(18)F(2)N(2)O(4)S(2).CHCl(3), is a novel stable compound of the N-F class of reagents containing two R(2)N-F functionalities. The compound, as the chloroform solvate, is the first such bis(N-F) compound to be structurally characterized. It adopts a solid-state structure in which the two aromatic rings are antiperiplanar and a combination of weak C-H...F and C-H...O hydrogen bonds [distances and angles range from 3.265 (4) to 3.439 (4) A and 150 to 170 degrees, respectively] and pi-stacking between the rings of different molecules (separations of 3.717 and 3.926 A) results in a solid-state structure containing well defined channels in which CHCl(3) solvent molecules are located. The N-F distances are 1.428 (3) and 1.433 (3) A.

catena-Poly[dibromozinc(II)-mu-ethylenediamine-N:N']: resolution of structural anomalies resulting from the interpretation of vibrational spectra.

The title structure, [ZnBr2(C2H8N2)], is made up of infinite -ZnBr2-(en)-ZnBr2-(en)- zigzag chains. Each repeat unit contains a trans ethylenediamine ligand [N-C-C-N -179 (1) degrees ], which bridges two approximately tetrahedral but crystallographically distinct Zn atoms. One Zn atom is bisected by a crystallographic twofold axis, whereas the other has mirror symmetry. Even though the crystal packing does not allow significant interaction between Zn and N atoms on adjacent chains, it does facilitate extensive intermolecular N-H...Br hydrogen bonding (N...H 2.69-2.96 A).

Cytotoxic Michael-type amine adducts of alpha-methylene lactones alantolactone and isoalantolactone.

Two series of cytotoxic (IC50, K562 cell line, 1-24 microM) alpha-aminomethyl substituted lactones 3 and 4 were prepared by stereoselective Michael-type addition of amines to alantolactone (1) and isoalantolactone (2). The lactones 1 and 2 and their amine adducts induce apoptosis and act as alkylating agents.

Crystal engineering of microporous 'Chinese-lantern' compounds to improve their ability to reversibly adsorb sulfur dioxide.

Three new 'Chinese lantern' complexes [XMn(mu-dppO2)4MnX](2+)2X-.4MeOH.Me2CO [X = Cl, Br, I; dppO2 = 1,3-bis(diphenylphosphinoyl)propane], have been structurally characterised using single-crystal X-ray diffraction and shown to have increasing affinity for SO2 across the series Cl < Br < I via thermogravimetric measurements.

Disorder and twinning in molecular crystals: impurity-induced effects in adipic acid.

The variation in physical properties of crystals grown in the presence of additives or impurities have previously been attributed to lattice disorder developed during crystallization. Adipic acid crystallized in the presence of a variety of stereochemically related impurities typifies such behavior with disorder manifest in variations of dissolution rates and enthalpies of solution and fusion. In this case the most extreme habit, produced by the presence of added monoalkanoic acids, is a rounded dumbbell that was suggested previously to be a twinned crystal. In this contribution such crystals are fully characterized both through their external morphology and by means of single crystal X-ray diffraction. These techniques show that these particles are not twinned but rather are disordered single crystals comprising a small number of slightly misaligned domains. The interaction between additive and substrate is modeled and new additives selected that induce the formation of true mechanical twins in adipic acid.

Synthesis and crystal structure determination of some asymmetrical and symmetrical CR-type macrocyclic Schiff base complexes, with a single pendant coordinating 2-aminoethyl arm.

A novel, totally asymmetrical tripodal 2,3',4"-tetraamine ligand, N((CH2)2NH2)((CH2)3NH2)((CH2)4NH2), epb, has been synthesized. In the presence of copper(II) and nickel(II) ions it condenses with 2,6-diacetylpyridine in 1:1 ethanol-water solution, producing some new CR-type complexes with a pendant primary amino group. The X-ray crystal structure of the resulting copper(II) complex, [Cu(3,4(2)-CR)](PF6)2 (1), and two other related complexes, [Cu(2,4(2)-CR)](ClO4)2 (2) and [Cu(3,3(2)-CR)](ClO4)2 (3), are reported. Crystal data: complex 1, monoclinic, P2(1)/n, a = 8.366(3) A, b = 15.549(3) A, c = 20.283(2) A, beta = 98.73(2) degrees, V = 2607.8(11) A3, Z = 4, R1 = 0.0621, wR2 = 0.1615; complex 2, monoclinic, P2(1)/c, a = 7.981(10) A, b = 18.882(3) A, c = 15.185(3) A, beta = 96.40(2) degrees, V = 2275.7(6) A3, Z = 4, R1 = 0.0773, wR2 = 0.1635; complex 3, monoclinic, P2(1)/n, a = 7.8764(10) A, b = 15.361(2) A, c = 19.370(2) A, beta = 100.330(10) degrees, V = 2305.7(5) A3, Z = 4, R1 = 0.0537, wR2 = 0.1397. In all of these, copper atoms are bonded to four nitrogens of a macrocyclic ring and a nitrogen of the pendant arm. The arrangements are slightly distorted square-pyramidal in which the primary amino groups occupy apical positions and have the longest Cu-N distances. For all isomers, copper(II) ions are somewhat above the plane of the imino-pyridine system of the macrocylic ring in the direction of the pendant coordinated primary amino group.