: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Bioinorganic photochemistry: frontiers and mechanisms.

The majority of clinically approved anticancer drugs are characterized by a narrow therapeutic window that results mainly from a high systemic toxicity of the drugs in combination with an evident lack of tumor selectivity. Besides the development of suitable galenic formulations such as liposomes or micelles, several promising prodrug approaches have been followed in the last decades with the aim of improving chemotherapy. In this review we elucidate the two main concepts that underlie the design of most anticancer prodrugs: drug targeting and controlled release of the drug at the tumor site. Consequently, active and passive targeting using tumor-specific ligands or macromolecular carriers are discussed as well as release strategies that are based on tumor-specific characteristics such as low pH or the expression of tumor-associated enzymes. Furthermore, other strategies such as ADEPT (antibody-directed enzyme prodrug therapy) and the design of self-eliminating structures are introduced. Chemical realization of prodrug approaches is illustrated by drug candidates that have or may have clinical importance.

Prodrug strategies in anticancer chemotherapy.

Lighting the way to see inside the live cell with luminescent transition metal complexes

The rich photophysical properties of luminescent inorganic and organometallic transition metal complexes, such as their intense, long-lived, and environment-sensitive emission, render them excellent candidates for biological and cellular studies. In this Perspective, we review examples of biological probes derived from luminescent transition metal complexes with a d6, d8, or d10 metal center. The design of luminescent covalent labels and noncovalent probes for protein molecules is discussed. Additionally, the recent applications of these complexes as cellular probes and bioimaging reagents are described. Emphasis is put on the structural features, photophysical behavior, biomolecular interactions, cellular uptake, and intracellular localization properties of luminescent transition metal complexes.

Applications of luminescent inorganic and organometallic transition metal complexes as biomolecular and cellular probes

Photooxidation of DNA by a cobalt(II) tridentate complex.

Oxidative cleavage of DNA by tridentate copper (II) complex.

Synthesis, characterization and DNA binding studies of two mixed ligand complexes of ruthenium(II).

Synthesis, characterization and DNA binding studies of a ruthenium(II) complex.

Two mixed ligand complexes of ruthenium(II) 				[Ru(bzimpy)(bpy)(OH2)]2+ 				(1) and [Ru(bzimpy)(phen)(OH2)]2+ 				(2) have been synthesized and characterized by FAB mass, 1H NMR, cyclic voltammetry and spectroelectrochemical measurements. Controlled potential electrolysis of these complexes results in the conversion of ruthenium(II) to ruthenium(III) at 0.6 V and ruthenium(III) to ruthenium(IV) at 0.8 V vs. SCE. The binding constant of these complexes with DNA has been determined electrochemically and found to be (3.58 ± 0.25) 				× 104 and (2.87 ± 0.2) 				× 104 M−1. Viscosity measurements suggest that these complexes bind with DNA through intercalation. Such intercalative binding to DNA has been found to induce chirality to the two complexes. Electrochemically generated ruthenium(IV) species of these complexes have been found to bring about oxidative cleavage in DNA.

V. G. Vaidyanathan

Papers

Photooxidation of DNA by a cobalt(II) tridentate complex.

Oxidative cleavage of DNA by tridentate copper (II) complex.

Synthesis, characterization and DNA binding studies of two mixed ligand complexes of ruthenium(II).

Synthesis, characterization and DNA binding studies of a ruthenium(II) complex.

Synthesis, characterization and electrochemical studies of mixed ligand complexes of ruthenium(ii) with DNA.