Ligand exchange and spin state equilibria of Fe(II)(N4Py) and related complexes in aqueous media.

We report the characterization and solution chemistry of a series of Fe(II) complexes based on the pentadentate ligands N4Py (1,1-di(pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine), MeN4Py (1,1-di(pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)ethanamine), and the tetradentate ligand Bn-N3Py (N-benzyl-1,1-di(pyridin-2-yl)-N-(pyridin-2-ylmethyl)methanamine) ligands, i.e., [Fe(N4Py)(CH(3)CN)](ClO(4))(2) (1), [Fe(MeN4Py)(CH(3)CN)](ClO(4))(2) (2), and [Fe(Bn-N3Py)(CH(3)CN)(2)](ClO(4))(2) (3), respectively.

Mononuclear Fe(II)-N4Py complexes in oxidative DNA cleavage: structure, activity and mechanism.

A series of monotopic N4Py (N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine, 1) derived ligands have been prepared and evaluated in the iron catalyzed oxidative cleavage of pUC18 DNA, in the presence and absence of external reducing agent DTT. The mononuclear iron(II) complexes induce efficient DNA cleavage in air with a low catalyst loading. It was demonstrated that covalent attachment of 9-aminoacridine, ammonium group or 1,8-naphthalimide leads to increased DNA cleavage activity in the presence of a reductant.

Multinuclear non-heme iron complexes for double-strand DNA cleavage.

The cytotoxicity of the anti-tumor drug BLM is believed to be related to the ability of the corresponding iron complex (Fe-BLM) to engage in oxidative double-strand DNA cleavage. The iron complex of the ligand N4Py (Fe-N4Py; N4Py = N,N-bis(2-pyridyl)-N-bis(2-pyridyl)methylamine) has proven to be a particularly valuable spectroscopic and functional model for Fe-BLM. It is also a very active oxidative DNA-cleaving agent.

Double strand DNA cleavage with a binuclear iron complex.

Covalently linking two single strand DNA cleaving agents resulted in a new biomimetic binuclear iron complex capable of effecting oxidative double strand DNA cleavage.

Electronic properties, redox behavior, and interactions with H2O2 of pH-sensitive hydroxyphenyl-1,2,4-triazole-based oxovanadium(V) complexes.

The syntheses and spectroscopic characterization of two 1,2,4-triazole-based oxovanadium(V) complexes are reported: 1- [VO2L1]- and 2 [(VOL2)2(OMe)2] (where H2L1 = 3-(2'-hydroxyphenyl)-5-(pyridin-2' '-yl)-1H-1,2,4-triazole, H3L2 = bis-3,5-(2'-hydroxyphenyl)-1H-1,2,4-triazole). The ligand environment (N,N,O vs O,N,O) is found to have a profound influence on the properties and reactivity of the complexes formed. The presence of the triazolato ligand allows for pH tuning of the spectroscopic and electrochemical properties, as well as the interaction and stability of the complexes in the presence of hydrogen peroxide.

Enhanced selectivity in non-heme iron catalysed oxidation of alkanes with peracids: evidence for involvement of Fe(IV)=O species.

Catalytic alkane oxidation with high selectivity using peracids and an (N4Py)Fe complex is presented and the role of [(N4Py)Fe(IV)=O]2+ species, molecular oxygen and hydroxyl radicals in the catalysis is discussed.

Synthesis of a non-heme template for attaching four peptides: an approach to artificial iron(II)-containing peroxidases.

We are developing all-synthetic model cofactor-protein complexes in order to define the parameters controlling non-natural cofactor activity. The long-term objective is to establish the theoretical and practical basis for designing novel enzymes. A non-heme pentadentate ligand (N4Py) is being developed as a template for the site-specific attachment of a designed four-helix bundle.