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The crystal structures of the Werner clathrates Ni(NCS)2(isoquinoline)4 (H) with para-xylene (px), meta-xylene (mx) and ortho-xylene (ox) have been elucidated. The kinetics of thermal decomposition of the three inclusion compounds were performed using the isothermal technique of Flynn and Wall. Selectivity of H for the xylene isomers was determined for both the liquid and vapour phase binary mixtures of the xylenes. The chosen ligand has a larger aromatic system to improve the possible π interactions between H and the selected guests. The planarity of the isoquinoline ligand causes H rigidity and its selectivity was compared to a related Werner complex containing the more flexible 4-phenylpyridine.

Diacetoneketogulonic acid was used to separate primary amines from their racemic modifications and the selectivity of the acid was rationalized by lattice energy calculations and analyzing the weak interactions around the captured amines.

The isomers of xylene have been separated by enclathration using three host compounds: 9,9'-bianthryl (H1), 9,9'-spirobifluorene (H2) and trans-2,3-dibenzoylspiro[cyclopropane-1,9-fluorene] (H3). The structures of each host with a single xylene isomer have been elucidated and, for H1, the relative lattice energies of the clathrates with ortho- and para-xylene have been evaluated.

3-Methylcyclohexanone is only partially resolved by crystallisation with a chiral diol host compound (ee 40%), but when recrystallised from an equimolar mixture of the chiral diol host and a similar but achiral host we obtain complete resolution. The latter host acts as a nucleation inhibitor and the enhanced resolution is attributed to kinetic effects.

The selectivity profile for the resolution of mandelic acid by quinine is dominated by structures comprising (QUIN(+))(MAND(-)) salts with Z' = 3 which contain (R)-, (R)- and (S)-mandelate anions.

The structures of the inclusion compounds 4,4'-(cyclohexane-1,1-diyl)diphenol-3-chlorophenol (1/1) and 4,4'-(cyclohexane-1,1-diyl)diphenol-4-chlorophenol (1/1), both C(18)H(20)O(2).C(6)H(5)ClO, are isostructural with respect to the host molecule and are stabilized by extensive host-host, host-guest and guest-host hydrogen bonding. The packing is characterized by layers of host and guest molecules. The kinetics of thermal decomposition follow the R2 contracting-area model, kt = [1 - (1 - alpha)1/2], and yield activation energies of 105 (8) and 96 (8) kJ mol(-1), respectively.

Ambroxol theophylline-7-acetate (ACE) is the salt obtained by reaction of equimolar amounts of ambroxol (AMB), a drug showing mucolytic and expectorant properties, and theophylline-7-acetic acid (TAA), a xanthine derivative with specific bronchodilator activity. ACE is used for the treatment of bronchial and pulmonary diseases (bronchitis, asthma, emphysema, chronic obstructive disease). Recrystallization experiments of ACE resulted in the isolation of two polymorphs (monotropically related) and four solvated forms. X-ray diffractometry, DSC, TGA, and HSM techniques were used to investigate the forms that are obtained by thermal desolvation of the solvates. The phase diagram of the TAA-AMB binary system was constructed by performing thermal analyses on mixtures of TAA-AMB and of each component plus the interaction compound (TAA-ACE and ACE-AMB). The Schroeder-Van Laar equation proved to be a very useful tool for checking the consistency between the experimental data and the theoretical model related to the general system, showing complete miscibility in the liquid phase and complete immiscibility in the solid phase., ((c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.)

Investigation of the selectivities of two diol organic hosts for pairs of small organic guests gave interesting results which could be correlated with the crystal structures of the inclusion compounds containing mixtures of the two guests; these structures were compared with those of the single guest inclusion compounds.

The host compound tetra(3-hydroxy-3,3-diphenyl-2-propynyl)ethene, TET, forms inclusion compounds with acetone, dimethyl sulfoxide, dioxane and pyridine. All the structures were successfully solved in the triclinic space group P1[combining macron]. We found variable host : guest ratios for the acetone (TET.ACE, H : G = 1 : 4), dimethyl sulfoxide (TET.DMSO, H : G = 1 : 4) and pyridine compounds (TET.PYR, H : G = 1 : 5). Solutions of the host compound and dioxane formed TET.2DIOX, H : G = 1 : 2 when left to crystallise at room temperature, whereas TET.4DIOX, H : G = 1 : 4 was formed during crystal growth at low temperature. We have correlated the structures with their thermal stabilities and kinetics of desolvation.

The structures of bis[(R)-(+)-1-phenylethylammonium] (2R,3R)-(-)-2,3-di-p-toluoyloxybutanedioate methanol disolvate monohydrate, 2C8H12N(+).C20H16O8(2-).2CH4O.H2O, (I), and bis(benzylammonium) (2R,3R)-(-)-2,3-di-p-toluoyloxybutanedioate dihydrate, 2C7H10N+.C20H16O8(2-).2H2O, (II), exhibit extensive hydrogen bonding, with (N-)H...O and (O-)H...O distances in the ranges 2.716 (2)-2.929 (3) and 2.687 (2)-2.767 (2) angstroms, respectively, in (I), and 2.673 (2)-2.888 (2) and 2.785 (2)-2.931 (2) angstroms, respectively, in (II). The amine groups are protonated and the carboxylate groups of the tartrate anions are fully deprotonated. The conformation of the toluoyltartrate anion and its molecular parameters are similar in both structures.

A series of clathrates comprising the xanthenol host, 9-(4-methoxyphenyl)-9H-xanthen-9-ol, with a variety of aromatic guests displays similar structures in the space group P(-1). We have elucidated the structures of the inclusion compounds H x 1/2G, where H is 9-(4-methoxyphenyl)-9H-xanthen-9-ol and G is benzene, o-, m- and p-xylene. The structures are isostructural with respect to the host and display consistent (Host)-OH...O-(Host) hydrogen bonding. The guests lie on a centre of inversion and with the exception of the symmetrical guests, benzene and p-xylene, are disordered. An interesting case arises with m-xylene, which is ordered at low temperature (113 K) with both the host and guest molecules in general positions. At a higher temperature (283 K) the inclusion compound with m-xylene fits the series. We have correlated the structures with their thermal stabilities, guest exchange and kinetics of desolvation.

The host xanthenol compound forms a 1:1 clathrate with dioxane, namely 9-(1-naphthyl)-9H-xanthen-9-ol-1,4-dioxane, C23H16O2.C4H8O2. The structure of this clathrate is reported, along with a study of the kinetics of desolvation and the determination of an activation energy. The guest molecules are stabilized by O(host)-H...O(guest) hydrogen bonds [O-H = 0.968 (2) A, O...O = 2.7532 (13) A and O-H...O = 151.9 (4) degrees].

The structures of the inclusion compounds formed by the host H = 9,9'-(biphenyl-4,4'-diyl)bis(fluoren-9-ol) with N,N-dimethylacetamide (H.2DMA and H.4DMA), 1,4-dioxane (H.3DIOX), methyl ethyl ketone (H.2MEK), as well as that of the apohost have been elucidated. The compounds were characterised by thermal analysis and solid state NMR, and the kinetics of desorption of H.4DMA, H.2DMA and H.3DIOX have been examined.

The enclathration selectivity of the host compound 2,2'-dihydroxyl-1,1'-binaphthyl, BINAP, towards the guests quinoline (Q), 2-methylquinoline (2MeQ), 6-methylquinoline (6MeQ) and 8-methylquinoline (8MeQ) were established by competition experiments as: BINAP.2(2MeQ) > BINAP.2Q > BINAP.2(8MeQ) > BINAP.2.5(6MeQ). The crystal structures of the inclusion compounds were elucidated and are all stabilised by (host)O-H...N(guest) hydrogen bonds. Thermal analysis yields the same sequence with respect to the relative stabilities. pH Control was employed to dramatically modify the selectivity profile of the pair of 2-methylquinoline (2MeQ) and 8-methylquinoline (8MeQ).

The isolation and structural elucidation by single crystal X-ray diffraction of triclinic and monoclinic modifications of an inclusion complex of beta-cyclodextrin with the same guest, methylparaben, are reported.

The macro properties of crystalline inclusion compounds depend on their structures. Their thermal stabilities are a function of the strength and the directionality of the various nonbonded interactions occurring in the host-guest assembly. Their lattice energies, as measured by the method of atom-atom potentials, correlate with the thermodynamics of the guest-release reactions and the selectivity that a given host displays for a particular guest. The kinetics of solid-host:vapor-guest reactions and of guest exchange are important in our understanding of catalytic processes. Crystal engineering, in which materials of predetermined properties may be synthesized, is still at the empirical stage.

Crystalline inclusion complexes between the cyclophane 1 and three isomers of picoline and lutidine were grown and their properties and structures were studied by X-ray analysis, thermal gravimetry (TG), and differential scanning calorimetry (DSC). In competition experiments, the cyclophane host, which by itself is only able to form weak Cbond;H.acceptor hydrogen bonds, is able to discriminate between the different picoline or lutidine isomers, although in some cases a strong concentration dependence of the preferred isomer is observed. In the three-component experiments, inclusion of 4-picoline is strongly favored when X(4-picoline)>0.35-0.39. Very similar results were obtained in the lutidine series. The fact that 2,4-lutidine is favored when X(2,4-lutidine)>0.2 indicates that the host prefers the isomer with the methyl group in 4-position relative to the nitrogen atom. The selectivities observed can be explained based on the assignment of the inclusion complexes to different adduct classes. In the case of the picoline isomers, the preference of 4-picoline was in good agreement with the calculated lattice energies for this series. The present work also shows that caution is advisable when deducing selectivity of crystalline inclusion compounds from guest competition experiments.

The diol host, 1,1'-bis-(4-hydroxyphenyl)cyclohexane (DHPC) and a number of xylidine isomers as guests formed a series of inclusion compounds that gave rise to various host:guest ratios controlled by crystallization temperatures. For the host DHPC with a particular xylidine isomer, the number of guests included generally decreases as the crystallization temperature increases. The crystal structures of these host-guest compounds were elucidated using single-crystal X-ray diffraction. Their thermal stabilities were characterized by TG and DSC analysis. The selectivity of enclathration by the host was measured by carrying out a series of competition experiments. The kinetics of guest decomposition were studied using isothermal and non-isothermal methods and reconciled with the crystal structures.

Investigation of the selectivity of a diol organic host for mixtures of DMF and DMSO, showed the formation of five inclusion compounds in which the stoichiometry varies in discrete steps and is determined by the composition of the liquid guest mixture; the structures of these compounds are described.

The crystal structures of the inclusion compounds formed between the host 2,2'-dihydroxy-1,1'-binaphthyl and the three picoline isomers have been elucidated and their lattice energies calculated. The selectivities of enclathration by the host have been measured by competition experiments. The thermal stabilities and activation energies of desolvation of the compounds have been determined. The kinetics of desolvation are correlated to the structures.

Five forms of the drug alprazolam have been identified by thermal analysis and X-ray powder diffraction (XRD). The single crystal X-ray structures of two of these species, a polymorph 1 and a dihydrate 2, were determined. The dihydrate crystallized from a solution of alprazolam in methanol containing traces of water. Species 3 and 4 are nonstoichiometric solvates with ethanol and acetonitrile, respectively. The differential scanning calorimetric curves for the solvates 2-4 are similar, showing a desolvation endotherm, followed by an exotherm associated with recrystallization, and a final endotherm for the fusion of alprazolam. The solvates 3 and 4 were shown to be isomorphous by XRD. The products of desolvation of 2-4 were identified by their XRD traces. Solvates 2 and 3 yield polymorph 1 on desolvation, whereas solvate 4 yields a different polymorph.

The products of recrystallization of tenoxicam (4-hydroxy-2-methyl-N-2-pyridinyl-2H-thieno[2,3-e]-1,2-thiazine-3- carboxamide 1,1-dioxide) from ethanol and acetonitrile were investigated by thermogravimetric analysis, differential scanning calorimetry, and X-ray diffraction. Recrystallization from ethanol yielded a polymorph designated 1, and recrystallization from acetonitrile gave a solvate 2 with 1:1 stoichiometry. The structures of 1 and 2 were determined by single-crystal X-ray methods. Polymorph 1 is triclinic, space group P1, with Z = 4; solvate 2 is monoclinic, space group P2(1)/n, with Z = 4. In both crystal structures, the tenoxicam molecule exists in the zwitterionic form, adopting a planar conformation that is stabilized by two intramolecular hydrogen bonds (N(+)-H...O and N-H...O-). Tenoxicam molecules associate by N(+)-H...O and C-H...N hydrogen bonding in both crystal structures. Desolvation of 2 yields a polymorph of tenoxicam that is different from polymorph 1. A study of the kinetics of the desolvation of 2 by dynamic thermogravimetry yielded estimates of the activation energy in the range 69-72 kJ.mol-1. From a comparison of experimental and simulated X-ray powder diffraction patterns, neither 1 nor 2 undergoes a polymorphic transition upon grinding. X-ray patterns based on the single-crystal X-ray data for 1 and 2 are presented as reliable references for their identification.

The crystal structures and thermal decomposition of three solvated forms of the antibacterial drug succinylsulfathiazole (SST) have been studied. The solvates, with 1:1 host-guest stoichiometry, are SST x 1-butanol (1) SST x 1-pentanol (2), and SST x 1,4-dioxane (3). Solvates 1 and 2 crystallize in the triclinic system, space group P1, with two formula units per cell, and are nearly isostructural. The OH groups of the guest molecules in both solvates engage in hydrogen bonding to the host SST and occupy cavities in the crystals. Solvate 3 is triclinic, space group P1, with two formula units per cell, but the two independent solvent molecules are located in crystallographically distinct channels. In one channel, solvent molecules are hydrogen bonded to the host while, in the other, they are held by van der Waals interactions only. The structural results are in accord with thermogravimetric and differential scanning calorimetric data which indicate one-step desolvation for 1 and 2 but two-step desolvation for 3. X-ray powder diffraction was used to attempt identification of the polymorphic forms of SST resulting from desolvation of 1-3. Desolvation of 1 and 3 appears to yield pure polymorphs of SST while 2 yields a mixture of polymorphs. The activation energies for the desolvation of the nearly isomorphous solvates 1 and 2 were found by dynamic thermogravimetry to be 155 and 149 kJ mol(-1), respectively.

Single crystals of anhydrous metronidazole benzoate and its monohydrate were isolated from the same aqueous solution and studied by X-ray diffraction. Anhydrous metronidazole benzoate gives crystals belonging to the triclinic space group P1 and, at ambient temperature, a = 6.649 (2), b = 8.666(1), c = 11.940(3) A, alpha = 76.70(2)degrees, beta = 76.72(2)degrees, gamma = 87.56(2)degrees, V = 651.6(3) A3, Z = 2, and Rw(F) = 0.053. Metronidazole benzoate monohydrate gives crystals belonging to the triclinic space group P1 and, at ambient temperature, a = 7.544(1), b = 7.990(1), c = 12.329(4) A, alpha = 94.33(2)degrees, beta = 97.40(2)degrees, gamma = 101.36(1)degrees, V = 718.6(3) A3, Z = 2, and Rw(F) = 0.041. Thermomicroscopy, differential scanning calorimetry, and thermogravimetry were used for initial characterization of the title species and to investigate possible phase changes on heating. The crystal structure analyses revealed that the metronidazole benzoate molecule adopts different conformations in the two crystal forms. Crystal cohesion in the anhydrous form is due to van der Waals interactions only, whereas in the monohydrate, there is strong intermolecular hydrogen bonding mediated by water molecules. Computer-generated X-ray powder patterns for the two species are distinctly different and serve as reference for their identification.

The 1:1 inclusion compounds of cholic acid with methanol (C24H40O5.CH4O), ethanol (C24H40O5.C2H6O) and 1-propanol (C24H40O5.C3H8O) crystallize in the P2(1)2(1)2(1) space group with unit-cell dimensions at 293 K: a = 15.198 (6), b = 11.625 (7), c = 14.560 (9) A; a = 14.653 (7), b = 11.739 (4), c = 15.045 (2) A; and a = 15.026 (2), b = 11.864 (9), c = 14.951 (4) A; Z = 4. The structures were solved using direct methods. Full-matrix least-squares refinement reduced the conventional R factor to values of 0.109, 0.066 and 0.071, respectively. The alcohol molecules are contained in cavities created by the cholic acid molecules and are involved in the hydrogen-bonding scheme consisting of five unique hydrogen bonds. Statistical disorder is observed for the ethanol and 1-propanol molecules.

A single calculus from the bladder of a Beagle bitch has been analyzed by a multiple technique approach employing x-ray diffraction, infrared spectroscopy, scanning electron microscopy, x-ray fluorescence spectrometry, atomic absorption spectrophotometry and density gradient fractionation. The qualitative and quantitative data obtained showed excellent agreement, lending confidence to such an approach for the evaluation and understanding of stone disease.

10 urinary calculi have been qualitatively and quantitatively analysed using X-ray diffraction, infra-red, scanning electron microscopy, X-ray fluorescence, atomic absorption and density gradient procedures. Constituents and compositional features which often go undetected due to limitations in the particular analytical procedure being used, have been identified and a detailed picture of each stone's composition and structure has been obtained. In all cases at least two components were detected suggesting that the multiple technique approach might cast some doubt as to the existence of "pure" stones. Evidence for a continuous, non-sequential deposition mechanism has been detected. In addition, the usefulness of each technique in the analysis of urinary stones has been assessed and the multiple technique approach has been evaluated as a whole.