Boron complexes of [14]triphyrins(2.1.1) were prepared from free-base [14]triphyrins(2.1.1) with phenylboron dichloride. The absorption spectrum of the meso-free β-alkyl-triphyrin boron complex in CH2Cl2 showed a broad weak band at around 640 nm assigned to transition from B-phenyl to the triphyrin, while that of the meso-aryl benzotriphyrin boron complex showed only Soret and Q bands.

Native and reconstituted myoglobin were prepared and their c.d. spectra recorded in the Soret region. Time-dependent changes in dichroism following reconstitution were observed and related to haem orientational disorder. Comparative c.d. studies, in agreement with n.m.r. studies, reveal that the degree and nature of this disorder are species-dependent.

The circular dichroism spectra of native and recombined vinyl-(protojhematin horseradish peroxidase are identical, which confirms the proper position of the reintroduced group. The same observation and conclusion applies to the light absorption spectra. Circular dichroism and light absorption spectra of seven artificial peroxidases, prepared from apoperoxidase and 2,4substituted hematins, have ...

The absorption spectrum of deoxygenated human hemoglobin differs from that of the isolated a! and /3 chains, and the difference has been ascribed to the conformational changes on which depends the cooperative ligand binding. Studies on hybrid-heme hemoglobins, in which one chain contains protoheme and the other chain mesoheme, showed that the prominent peak in the Soret region of the difference...

In the present approach, a two-dimensional steady MHD free convection flow and mass transfer over a stretching sheet has been analyzed numerically including the Dufour and Soret effects with a magnetic field. The governing differential equations of the problem have been transformed into a system of non-dimensional differential equations, which are then solved numerically using a sixth-order Run...

We have performed gas-phase absorption spectroscopy in the Soret-band region of chlorophyll (Chl) a and b tagged by quaternary ammonium ions together with time-dependent density functional theory (TD-DFT) calculations. This band is the strongest in the visible region of metalloporphyrins and an important reporter on the microenvironment. The cationic charge tags were tetramethylammonium, tetrab...

Soret band lifetimes of the free-base tetraphenylporphine (H(2)TPP) and Cu(ii) tetraphenylporphine (Cu(II)TPP) at 408 nm have been directly measured with femtosecond (fs) resolution using the fluorescence-upconversion technique for the first time, giving tau = 68 +/- 15 and 63 +/- 15 fs, respectively, in benzene solvent.

New stochastic models of thermodiffusion are constructed and their hydrodynamical limits are studied through a first order Chapman-Enskog expansion. These models differ from earlier ones by taking into account all first order contributions proportional to the temperature gradient and, thus, allow for both positive and negative Soret coefficients, in accordance with observations.

The effects of thermo-diffusion (Soret effect) and diffuso-thermal gradients (Dufour effect) on the unsteady incompressible magneto-hydrodynamic (MHD) free convection flow with mass transfer past a semi-infinite vertical plate in a Darcian porous medium in the presence of significant thermal radiation, first order homogenous chemical reaction and viscous heating are analyzed. The governing diff...