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Christopher J Sumby

Publications and source records attributed to Christopher J Sumby.

6 recordsLinked to original sources
PubMed2006

Silver(I) complexation of linked 2,2'-dipyridylamine derivatives. Synthetic, solvent extraction, membrane transport and X-ray structural studies.

Synthesis of the 2,2'-dipyridylamine derivatives di-2-pyridylaminomethylbenzene 1, 1,2-bis(di-2-pyridylaminomethyl)benzene 2, 1,3-bis(di-2-pyridylaminomethyl)benzene 3, 2,6-bis(di-2-pyridylaminomethyl)pyridine 4, 1,4-bis(di-2-pyridylaminomethyl)benzene 5, and 1,3,5-tris(di-2-pyridylaminomethyl)benzene 6 are reported together with the single-crystal X-ray structures of 2, 3, and 5. Reaction of individual salts of the type AgX (where X = NO(3)(-), PF(6)(-), ClO(4)(-), or BF(4)(-)) with the above ligands has led to the isolation of thirteen Ag(I) complexes, nine of which have also been characterised by X-ray diffraction. In part, the inherent flexibility of the respective ligands has resulted in the adoption of a range of coordination arrangements. A series of liquid-liquid (H(2)O/CHCl(3)) extraction experiments of Ag(I) with varying concentrations of 1-6 in the organic phase have been undertaken, with the counter ion in the aqueous phase being respectively picrate, perchlorate and nitrate. In general, extraction efficiencies for a given ionophore followed the Hofmeister order of picrate > perchlorate > nitrate; in each case the tris-dpa derivative 6 acting as the most efficient extractant of the six systems investigated. Competitive seven-metal bulk membrane transport experiments (H(2)O/CHCl(3)/H(2)O) employing the above ligands as the ionophore in the organic phase and equimolar concentrations of Co(II), Ni(II), Zn(II), Cu(II), Cd(II), Pb(II) and Ag(I) in the aqueous source phase were also undertaken, with transport occurring against a pH gradient. Under the conditions employed 1 and 5 yielded negligible transport of any of the metals present in the source phase while sole transport selectivity for Ag(I) was observed for 2-4 and 6.

Journal Article↗
PubMed2006

Tris(pyridylmethylamino)cyclotriguaiacylene cavitands: an investigation of the solution and solid-state behaviour of metallo-supramolecular cages and cavitand-based coordination polymers.

The synthesis of the three isomeric tris(pyridylmethylamino)cyclotriguaiacylene cavitands is reported, along with the crystal structures of the 2- and 4-pyridyl derivatives. The generality of a previously described [Ag(2){tris(3-pyridylmethylamino)cyclotriguaiacylene}(2)](2+) dimeric capsule motif and the [Ag(4){tris(4-pyridylmethylamino)cyclotriguaiacylene}(4)](4+) tetrahedron with several silver salts was confirmed in the solid state and the corresponding solution species were investigated by NMR spectroscopy. Host-guest interactions in these systems have been probed and these interactions are demonstrated to alter and influence the self-assembly outcome of the reaction. Notably, introduction of larger glutaronitrile guest molecules to the [Ag(4)L(4)](4+) tetrahedron system prevents formation of the tetrahedral structure, resulting instead in the formation of a 4.8(2) coordination network in the solid state. In the absence of templating acetonitrile guests in the [Ag(2)(3)(2)](2+) capsule system, formation of a cage-based one-dimensional coordination polymer is observed.

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PubMed2004

Interwoven 2-D coordination network prepared from the molecular host tris(isonicotinoyl)cyclotriguaiacylene and silver(I) cobalt(III) bis(dicarbollide).

A new 3-fold symmetric molecular host, tris(isonicotinoyl)cyclotriguaiacylene, has been synthesized from cyclotriguaiacylene and isonicotinoyl chloride hydrochloride in 70% yield. Its crystal structure shows dimerization of the host molecules into a capsule-like arrangement. When reacted with Ag[Co(C(2)B(9)H(11))(2)], the host forms a 1-D [ML(2)](n) coordination polymer, which assembles into a 2-D interwoven network through a similar dimerization of the host moieties around acetonitrile guests. Thus, the network structure represents an elegant example whereby the solid state structure of the building blocks is echoed in the resulting supramolecular assembly. The 2-D sheets are further stabilized by pi...pi stacking interactions between pyridyl donors of alternate 1-D coordination polymers.

Journal Article↗
PubMed2004

Building blocks for cyclotriveratrylene-based coordination networks.

The incorporation of three-fold symmetric organic host molecules into coordination polymers should allow for the construction of new and interesting network structures, capable of multiple inclusion behaviour. A range of new multi-dentate bridging ligands/molecular hosts have been prepared by appending nitrogen-containing heterocycles to either cyclotricatechylene, or cyclotriguaiacylene cores. These compounds were obtained in a single-step reaction from readily available precursors, with moderate to good yields, and characterised by a combination of NMR spectroscopy, mass spectrometry and elemental analysis. Two of the new compounds were characterised by X-ray crystallography, revealing different modes of self inclusion behaviour, which indicate the potential importance of [small pi]-donor stabilisation by CTV derivatives in host-guest chemistry.

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