Janet L. Shaw

Acid-Base and Aggregation Behavior of Water Soluble N-confused Porphyrin

The acid-base and aggregation behavior of water soluble meso-tetrakis(p-sulfonato-phenyl)N-confused porphyrin was explored using UV-visible spectroscopy. Stepwise protonation events were observed in acidic media with pK4 = 5.8 and pK3 = 7.7, and spectroscopic evidence suggests the formation of polymeric aggregates at low pH. meso-tetrakis(p-sulfonatophenyl)N-confused porphyrin was found to obey Beers Law in dimethylformamide and methanol over the concentration range of 10-4 to 10-6 M and at low concentration in water. Deviations in water at higher concentration were analyzed to determine KD values for aggregate formation in the presence and absence of salt and buffer.

The synthesis of isostructural Mo2+ porphyrin and N-confused porphyrin complexes

We have synthesized the first early transition metal N-confused porphyrin complex Mo(NCTPP)(pip)2; this species is isostructural to its normal porphyrin analog Mo(TPP)(pip)2 but exhibits significant electronic differences arising from the inversion of a single pyrrolic group.

Charged and confused: Meso-tetrakis(p-methoxycarbonyl-phenyl) N-confused porphyrin as a precursor to water soluble variants

A metal-free meso-tetrakis(p-methoxycarbonylphenyl) N-confused porphyrin (1) was prepared as the precursor for water-soluble derivatives by the reaction between pyrrole, methyl-4-formylbenzoate, and MSA. Tautomeric behavior of the porphyrin 1 in polar and non-polar solvents was probed by 1H NMR, UV-vis, MCD, steady-state fluorescence, and high-resolution ESI methods and was found to be similar to the previously reported metal-free N-confused porphyrins. The electronic structure and the nature of the excited states in 1 were correlated with the results obtained by density functional theory (DFT) and time-dependent DFT (TDDFT) calculations.

Preparation, characterization, and structural analysis of d8 palladium and platinum compounds containing amino acid ester derivatized diimine ligands. Observation of liquid crystal behavior

Abstract Eight new compounds, M(pyca(CH2)xCOOR)Cl2, M = Pd, Pt; R = Me, Et; x = 2, 3, 5, 11, were prepared. The resulting new complexes were characterized by 1H and 13C NMR spectroscopy and each was also structurally elucidated by X-ray crystallography. The compounds share general structural features, but there are differences in the alignment of the alkyl chain; as the chain lengthens, the chain straightens relative to the plane of the metal complex. For the dodecanoic ester derivatives, a nearly linear alkyl chain was observed. These longer alkyl derivatives show mesogenic behavior.

[Diphenyldi(pyrazol-1-yl)methane]­dinitratocobalt(II)

In the title compound, [Co(NO3)2(C19H16N4)], the diphenyldipyrazolylmethane ligand coordinates to CoII in a bidentate fashion forming a six-membered ring with an approximate boat configuration. The mean planes of the two pyrazolyl rings are separated by an angle of 39.6 (2)°. The coordination at the CoII center is best described as distorted octahedral with two NO3 − anions serving as bidentate ligands for charge balance. The dihedral angle between the mean planes of the two nitrate rings is 85.0 (1)° and that between the mean planes of the two phenyl rings is 73.7 (1)°. The crystal structure is stabilized by weak intermolecular C—H⋯O and intramolecular C—H⋯N hydrogen-bond interactions.