Biomedical subjects

Patrick Plitt

Publications and source records attributed to Patrick Plitt.

4 recordsLinked to original sources

PubMed2007

Dipyrrolyl-functionalized bipyridine-based anion receptors for emission-based selective detection of dihydrogen phosphate.

New cationic anion receptors, based on the use of pyrrole-substituted bipyridine and coordinated to transition metals, are described. Specifically, polypyridine-ruthenium and -rhodium cores have been functionalized to generate an anion binding site. The design was chosen to probe the influence of the pyrrole-to-pyrrole separation on anion-binding affinities and selectivities; this distance is greater in the new systems of this report (receptors 1 and 2) relative to that present in related dipyrrolyl quinoxaline based receptors 3 and 4. Solution-phase anion-binding studies, carried out by means of (1)H NMR spectroscopic titrations in [D(6)]DMSO and isothermal titration calorimetry (ITC) in DMSO, reveal that 1 and 2 bind most simple anions with substantially higher affinity than either 3 or 4. In the case of chloride anion, structural studies, carried out by means of single-crystal X-ray diffraction analyses, are consistent with the solution-phase results and reveal that receptors 1 and 2 are both able to stabilize complexes with this halide anion in the solid state.

2,2'-Dipyridyl↗

PubMed2005

N,N:N',N'-Bis(2,2'-dihydroxybiphenyl-3,3'-dimethylidene)benzene-1,2-diamine dimethyl sulfoxide tetrasolvate.

The title compound, 8,15,28,35-tetraazaheptacyclo[35.3.1.1(2,6).1(17,21).1(22,26).0(9,14).0(29,34)]tetraconta-1(41),2,4,6(42),7,9,11,13,15,17,19,21(43),22,24,26(44),27,29,31,33,35,37,39-docosaene-41,42,43,44-tetrol dimethyl sulfoxide tetrasolvate, C40H28N4O4.4C2H6OS, adopts a chair-shaped C(2h) symmetric conformation with crystallographically imposed inversion symmetry. Four intramolecular hydrogen bonds are observed between phenol O and imine N atoms.

Journal Article↗

PubMed2005

Biphenyl derived oxovanadium(IV) and copper(II) salen-type complexes--structure and redox tuning.

A series of vanadyl(IV) salen (N,N'-bis(salicylidene)ethylenediaminato)-type complexes (1-4) bearing phenyl or 2-hydroxyphenyl moieties have been prepared and characterized by means of mass spectrometry, infra-red, electron paramagnetic resonance (EPR), UV/Vis spectroscopy, cyclovoltammetry and X-ray crystallography. Their structures have been compared to their copper(II) analogs 5-8. Hydrogen intralinkages have been observed in the crystal structure of 5. The pendant hydroxy groups fine-tune the redox properties of the complexes. The catalytic activity in the oxygenation of ethyl phenyl sulfide to the corresponding sulfoxide was investigated. Results indicate that complex 1 bearing hydroxyphenyl subunits and a phenylene bridge is the most selective under these reaction conditions, with the smallest amount of the over-oxidized product, sulfone.

Journal Article↗

PubMed2004

Biphenyl derived Schiff-base vanadium(V) complexes with pendant OH-groups--structure, characterization and hydrogen peroxide mediated sulfide oxygenation.

A series of mononuclear oxovanadium(v) complexes of tridentate Schiff bases HL(1)-HL(4) and H(2)L(5)-H(2)L(8) derived from 6-phenylsalicylaldehyde and 6-(2-hydroxyphenyl)salicylaldehyde and four different amines was synthesized. The systematically selected ligands contain aliphatic or aromatic nitrogen, or alkoxy- and phenoxy-oxygen as third donor atom. The complexes were characterised by spectroscopic methods in solution and the solid state. Single-crystal X-ray analyses were performed with VO(2)L(1)(), VO(2)L(3)x1/2EtOH (), VO(2)L(4)(), VO(OiPr)L(7)xiPrOH, VO(OiPr)L(8) and H(2)L(8). For all compounds the vanadium(v) cores contain distorted tetragonal pyramidal geometry around the dioxo- and oxovanadium site at which the N(2)O- and NO(2)-donor ligands bind equatorially. Complexes and display intramolecular hydrogen bonding of the pendant hydroxyphenyl group to a coordinated oxygen trans to a nitrogen atom and therefore serve as suitable models for the native site of vanadium dependent haloperoxidases. Variable-temperature (1)H NMR spectra revealed significant hydrogen bond interaction in acetonitrile solution. In situ prepared catalysts are active for hydrogen peroxide mediated oxygenation of ethyl phenyl sulfide and showed complete conversion of the substrate to ethyl phenyl sulfoxide, together with small amounts of the corresponding sulfone, as detected by GC/MS after 10 min. The complex of H(2)L(7) turned out to be most efficient while HL(1) and HL(2) were completely inactive. Catalysis is supported by the pendant OH group in the complex of HL(3), the catalyst is twice as active as the complex of HL(4).

Biphenyl Compounds↗