Nitric oxide has been proposed to be transported by hemoglobin as a third respiratory gas and to elicit vasodilation by an oxygen-linked (allosteric) mechanism. For hemoglobin to transport nitric oxide bioactivity it must capture nitric oxide as iron nitrosyl hemoglobin rather than destroy it by dioxygenation. Once bound to the heme iron, nitric oxide has been reported to migrate reversibly fro...

The intramolecular proton transfer of 2-(2′-hydroxyvinyl)benzimidazole (HVBI) and 2-(2′-hydroxyphenyl)imidazole (HPI) in the ground state and in the 1ππ*, 1nπ*, and 3ππ* excited states has been studied at the HF/CIS/D95** level of theory. Their rotamerism reaction in the ground and 1ππ* excited states has been also analyzed. These systems are two different fragments of 2-(2′-hydroxyphenyl)benzi...

Strong Raman scattering is observed from iodine anions adsorbed at ca. 3% coverage on single layer graphene. In addition, the Raman signal from just one bromine intercalation layer inside three and four layer thick graphenes is observed. We analyze and model the intramolecular electronic, charge-transfer, and multiple reflection electromagnetic mechanisms responsible for this unusual sensitivit...

The cascade photoassisted synthetic strategy for accessing complex N,O-polyheterocycles of unprecedented molecular architecture is developed. It is based on intramolecular cycloadditions of aza-o-xylylenes formed in situ via excited-state intramolecular proton transfer (ESIPT) of o-acylanilides. The photoprecursors are synthesized via a two-step one-pot method from readily available starting ma...

Using single molecule fluorescence resonance energy transfer, we investigated the interaction between a quadruplex-binding ligand and the human telomeric G-quadruplex. The binding of quinolinecarboxamide macrocycle to telomeric DNA was essentially irreversible and selectively induced and favored one quadruplex conformation. The ligand-quadruplex complex displayed intramolecular dynamics includi...

Platinum(II) salts in combination with copper salts and molecular oxygen catalyse an unprecedented intramolecular transfer of heteroatoms to alkenes to yield aminooxygenation products under sustainable conditions.

Photoinduced twisted intramolecular charge transfer (TICT) of meso-(4-dimethylamino)phenylamino subporphyrin and meso-(4-nitro)phenylamino subporphyrin has been revealed by steady-state and time-resolved absorption/fluorescence experiments and quantum calculations. Subporphyrins and undergo molecular twisting at the Cmeso-N bond and the N-Cipso bond, respectively, to trigger intramolecular char...

We present a study of excited-state dynamics of two flavin cofactors: flavin-adenine dinucleotide (FAD) and flavin-mononucleotide (FMN). We used femtosecond mid-R transient absorption spectroscopy to study the effect of FAD conformation on its excited-state behavior. The conformation of FAD was modulated by changing the solvent polarity: in D(2)O, FAD is present predominantly in the "stacked" c...

Mechanistic aspects of some of the early electron transfer steps occurring in photosynthetic reaction centers are discussed. Starting from the normal modes of the redox cofactors involved in the electron transfer processes, we show how a series of quantities which regulate electron transfer rates, such as (i) the electron transfer active modes, (ii) the intramolecular reorganization energy, and...

The structures of the four lowest alanine conformers, along with their radical cations and the effect of ionization on the intramolecular proton transfer process, are studied using the density functional theory and MP2 method. The energy order of the radical cations of alanine differs from that of the corresponding neutral conformers due to changes in the basicity of the NH2 group upon ionizati...