Both Fe(III) and Cu(II) complexes of bleomycin (BLM), but not N-acetyl BLM . Fe(III), mediated the transfer of oxygen from iodosobenzene to organic substrates. In analogy with results obtained using certain cytochrome P-450 analogs, cis-stilbene was converted cleanly to the respective oxide, while no more than traces of trans-stilbene oxide were formed from trans-stilbene under identical condit...

Attempts to generate a proposed rhodium hydride catalytic intermediate instead resulted in isolation of (Cp*H)Rh(bpy)Cl (1), a pentamethylcyclopentadiene complex, formed by C-H bond-forming reductive elimination from the fleeting rhodium hydride. The hydride transfer ability of diene 1 was explored through thermochemistry and hydride transfer reactions, including the reduction of NAD(+).

The pigment-protein complexes CP43 and CP47 transfer excitation energy from the peripheral antenna of photosystem II toward the photochemical reaction center. We measured the excitation dynamics of the chlorophylls in isolated CP43 and CP47 complexes at 77 K by time-resolved absorbance-difference and fluorescence spectroscopy. The spectral relaxation appeared to occur with rates of 0.2-0.4 ps a...

The atomic-level picture of transmembrane protein complexes in the photosynthetic membrane has now been completed by the recent publication of crystal structures of cytochrome b(6)f and photosystem II. The two structures of cytochrome b(6)f, together with previously reported structures of the cytochrome bc(1) respiratory complex, provide a basis for understanding the central electron and proton...

Mixed-valence (partial charge transfer state) and segregated stacking are the key factors for constructing organic metals. Here, we discuss the ionicity phase diagrams for a variety of charge transfer systems to provide a strategy for the development of functional organic materials (Mott insulator, semiconductor, superconductor, metal, complex isomer, neutral-ionic system, etc.).

Molecular complexes of paraquat (PQ) with a few drug intermediates in alkaline medium, viz. 2,4,6-trimethylphenol, 4-benzyloxyphenol, 2-cyanophenol, 4-cyanophenol and a few drugs, viz. diclofenac sodium, salmeterol, omeprazole, esomeprazole and pantoprazole in methanol have been studied spectrophotometrically. All the complexes exhibit one charge transfer band each in the region where neither o...

Detailed molecular mechanisms of electron transfer-driven translocation of ions and of the generation of electric fields across biological membranes are beginning to emerge. The ideas inherent in the early formulations of the chemiosmotic hypothesis have provided the framework for this understanding and have also been seminal in promoting many of the experimental approaches which have been succ...

Visible light-driven intermolecular electron transfer was observed from a reduced species Ru(bpy)3+, photogenerated via a reductive quenching of the ruthenium photosensitizer by a diethyldithiocarbamate anion, to bioinspired [2Fe2S] model complexes of the iron-only hydrogenase active site. The results indicate that Ru(bpy)32+ can act as a photoactive functional model of the [4Fe4S] cluster, pla...

MP2/aug'-cc-pVTZ calculations have been carried out to investigate the halogen-bonded complexes formed when CO and CS act as electron-pair donors through C to ClF, ClNC, ClCl, ClOH, ClCN, ClCCH, and ClNH₂. CO forms only complexes stabilized by traditional halogen bonds, and all ClY molecules form traditional halogen-bonded complexes with SC, except ClF which forms only an ion-pair complex. Ion-...

Molecular complexes in the ratio 1:1 were formed in aqueous solution between various methoxysubstituted phenylisopropylamine (amphetamine) hydrochloride or oxalate salts and riboflavin deri­ vatives (flavin mononucleotide and flavin adenine dinucleotide). The association constants for these complexes were determined by the fluorescence quenching method as well as by the absorption method. The n...