Biomedical subjects
Publications and source records attributed to Philip J Cox.
The planar molecules of 6-hydroxy-1,3-benzoxathiol-2-one, C(7)H(4)O(3)S, are linked by extensive O-H.O and C-H.O hydrogen bonding and are further stablilized by face-to-face pi-pi interactions.
The 20-membered ring in 1,7,11,17-tetraoxa-2,6,12,16-tetraazacycloeicosane tetrahydrochloride, C(12)H(32)N(4)O(4)(4+).4Cl(-), adopts an endo conformation, while the 18-membered ring in 1,6,10,15-tetraoxa-2,5,11,14-tetraazacyclooctadecane tetrahydrochloride, C(10)H(28)N(4)O(4)(4+).4Cl(-), lies about an inversion centre and adopts a symmetrical conformation. In the crystal structures of both compounds, the cations and chloride anions are linked by N-H...Cl hydrogen bonds into planar sheets of molecules; the sheets are linked into three-dimensional networks via C-H...Cl hydrogen bonds.
An X-ray crystallographic study of dichlorophen has been performed. Intramolecular hydrogen bonding is found within the molecule and intermolecular hydrogen bonding is present between molecules. The formation of dimers within the crystal lattice has been established.
The crystal structure of the title compound, C(26)H(18)N(4)O(6)S, determined from synchrotron data with a small crystal, is characterized by the presence of whole-molecule disorder. In each molecule, the two planar portions are approximately perpendicular to one another and there are short intermolecular contacts between the nitro groups.
Molecules of the title compound, C(13)H(9)ClO(2), contain an intramolecular O-H...O hydrogen bond, and the two aromatic rings are inclined at 57.02 (3) degrees with respect to one another. The crystal structure is supported by C-H...O, C-H...pi and pi-pi interactions.
The crystal structures of the title compounds (both C(7)H(7)ClO) are characterized by two independent molecules in each of the asymmetric units and feature O--H...O, C--H...pi and pi-pi interactions. In addition, intermolecular C--H...Cl and intramolecular O--H...Cl interactions are present in 2-chloro-5-methylphenol. For each crystal, the non-covalent interactions emphasize the different spatial environments for the two independent molecules.
The crystal structure of 9-(3-methylbut-2-enyloxy)-7H-furo[3,2-g]chromen-7-one-4-methoxy-9-(3-methylbut-2-enyloxy)-7H-furo[3,2-g]chromen-7-one (0.926/0.074), 0.926C(16)H(14)O(4)*- x 0.074C(17)H(16)O(5), is characterized by two independent imperatorin molecules in the asymmetric unit, which exhibit different side-chain conformations. A small amount of phellopterin overlaps with one of the two imperatorin molecules. The supramolecular structure is supported by C--H...O, C--H...pi and pi-pi interactions.
Apart from the O and H atoms of the hydroxymethyl group, molecules of the title compound, C(7)H(7)BrO(2), are essentially planar. Both O atoms act as hydrogen-bond donors and acceptors, resulting in helical hydrogen bonding in the direction of the b axis and the formation of R(2)(2)(12) rings. Weaker C--H...pi interactions are also present.
Reaction of copper(I) chloride or bromide with equimolar amounts of the diphos ligand 1,3-propanebis(diphenylphosphine) and a heterocyclic thione (L) in acetonitrile/methanol solvent afforded mononuclear complexes of the type [CuX(dppp)(L)] with the diphosphine ligand acting as a chelating ligand. In contrast, copper(I) iodide under the same conditions gave the dimeric complex [Cu(mu-I)(dppp)](2), which contains doubly bridging iodo ligands. The structures of three complexes, namely, [CuCl(pymtH)(dppp)], [CuCl(pymtH)(dppp)], and [Cu(mu-I)(dppp)](2), have been established by single-crystal X-ray diffraction. Density functional calculations at the B3LYP level of theory provided a satisfactory description of the structural, bonding, electronic, and related properties of the [CuX(PH(3))(2)] and [CuX(1,3-pdp)] (1,3-pdp = 1,3-propane-di-phosphine) complexes and their dimers along with their associations with the pyrimidine-2-thione (pymtH) ligand. The interaction of the pymtH ligand with the Cu(I) metal center in these complexes corresponds to loose associations, the computed interaction energies predicted to be about 20 kcal/mol for all complexes in the series. The bonding mechanism of the thione ligand with the Cu(I) metal centers involves both a sigma-dative and pi-back-bonding components. The coordination of the pymtH ligand is further stabilized by X...H-N bond formation being more pronounced in the chloro than in the iodo derivatives. The Cu-X bond was also found to be a composite bond involving sigma- and pi-dative bonding components. Most important is the presence of pi-type MOs delocalized over the entire four-membered Cu(mu-X)(2)Cu ring, which supports a ring current and could probably account for the nearly equivalent Cu-X bonds in the rhombus. Moreover, all [Cu(mu-X)(PH(3))(2)](2) dimers exhibit a sigma-type MO corresponding to weak Cu.Cu interactions supporting through-ring intermetallic interactions, which seems to be responsible for the stabilization of the otherwise unstable antiaromatic Cu(mu-X)(2)Cu ring.
The molecular structure of the title compound, C(20)H(24)B(2)N(2)O(2)S, is characterized by a twofold rotation axis passing through the S atom and the midpoint of the C-C single bond in the thiophene ring. A coordinative N-->B bond is present in the boroxazolidine ring and a single N-H...O hydrogen bond [H...O 1.93 (3) A, N...O 2.829 (3) A and N-H...O 172 (2) degrees] links the molecules into a molecular ladder.