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The reactivity of an isolated, well-characterized manganese(V) [Mn.sup.V]-oxo complex is examined to verify that high-valent metal-oxo complexes are key intermediates for a wide range of enzymatic and synthetic processes. Direct assessment of the reactivity of the complex provides concrete experimental evidence that high-valent metal-oxo porphyrinoid complexes are capable of hydrogen atom abstraction despite weak oxidizing power.

Corrolazines are relatively new entries in the porphyrinoid family and most closely related to the ring-contracted, fully aromatic corrole compounds, both corrolazines(super 1-6) and corroles(super 6-11) impart enhanced stability to transition metals in high oxidation states. An attempt is made to show that the corrolazine system is better able to stabilize the high oxidation state copper center than the corresponding corroles.

Research has been conducted on the N,S(alkylthiolate) ligand. The preparation of this ligand has been carried out and the results indicate that it has reacted with zinc(II) and cobalt(II) to produce monomeric complexes.

Research has been conducted on two high-spin manganese(III) complexes. The results of high-field and -frequency electron magnetic resonance spectroscopy are described.

The manganese(III) porphyrazine complexes (Mn(Et2dtc)ODMAPz) and (Mn(Cl)ODMAPz) have eight peripheral dimethylamino groups attached to the beta-carbon atoms of the pyrrole rings. This was gleaned from the syntheses and determination of the X-ray crystal structures of the two complexes. Electrochemical data also reveal that the complexes are electron-rich and are an extremely strong reductant, while magnetic susceptibility measurements showed an S = 2 ground state with axial zero-field splitting.

Research has been conducted on the transition metal corrolazines with the corrole framework's meso carbon atoms replaced by N atoms. The syntheses of these complexes have been carried out and the details are reported.

The manganese(V) imido complex [(TBP8Cz)[Mn.sup.V](NMes)] (2) is prepared from the [Mn.sup. III) complex [(TBP8Cz)[Mn.sup.III (1)and thermolysis of mesityl azide. An X-ray structure of 2 shows a short Mn-N distance [1.595(4) Angstrom], consistent with the Mn-N triple bond expected for a manganese(V) imido species.

The new N2S(alkylthiolate)-coordinated Pb(super 2+) compound {2-methyl-1-[methyl(2-pyridin-2-ylethyl)amino]propane-2-thiolatolead perchlorate, [PATH-Pb][CIO4] is synthesized and characterized by X-ray diffraction and by [.sup.207.Pb] NMR. [[PATH-Pb].sup.+] is the first reported three-coordinate Pb complex with an alkenethiolate ligand and, hence, is a good model for Pb-cysteine interactions in proteins.

The bonding modes of a series of Zinc(II) and Iron(II) formate complexes are compared from crystallographic data and high-level DFT calculations. The results points to the higher reactivity of iron(II) in peptide deformylase as compared to zinc(II).

The zinc(II) complex (PATH)ZnOH, where PATH is an N(sub 2)S(thiolate) ligand, is examined for its ability to promote the hydrolysis of the phosphate triester tris(4-nitrophenyl) phosphate (TNP). Kinetic measurements, including a complete pH-rate profile which yields a kinetic pKa value for Zn-OH(sub 2) and a pH-independent rate constant for Zn-OH indicate a hybrid mechanism in which the zinc(II) ion has the dual role of providing a nucleophilic hydroxide and activating the substrate through coordination.

The structural and physicochemical properties of the manganese-corrolazine (Cz) complexes (TBP8Cz)Mn(super V) equivalent to O and (TBP8Cz)Mn(super III) (where TBP=p-tert-butylphenyl) are determined. The improved synthesis of manganese(III) and manganese(V)-oxo corrolazine complexes is accomplished.

Highly soluble octabutoxy-substituted Pc's are smoothly converted to the corresponding corrole framework. The synthesis of a novel series of P(super v)-TBCs along with the synthesis of a PV-Pc is described.

Research has been conducted on zinc(II) hydroxide complex containing alkylthiolate donor in coordination sphere. The authors report that this complex has been formed in aqueous solution from the zinc alkyl precursor complex dissolution ion H (sub)2 O.

Research shows that the peptide deformylases containing cysteinyl sulfur ligand belong to the zinc metalloproteases superfamily. Data discus the preparation of the mononuclear nitrogen-sulfur-thiolate metal mimics containing zinc or cobalt metal constituents as model analogues of peptide deformylase.

A report on the preparation of the metallocene porphyrazine complexes (Cp2Mo (super IV))(M(pz((S2-0;(B2)3)))), where the molybdocene unit was covalently attached to a dithiolene binding site on the macrocyclic periphery, was presented. The metallocene complexes conjoin the metalladithiolene metallacycle which was known to have extensive bond delocalization and aromatic properties. The synthesis of the complexes revealed that they were highly electroactive with five reversible redox couples.

X-ray crystallographic studies help determine the structures of two synthesized dinuclear ferric citrate complexes. One of the compounds has two octahedrally coordinated alkoxide-bridged iron atoms with a common edge. The second compound has three bridging citrate ligands and each ligand employs its alkoxide group to bind two ferric ions. Magnetic susceptibility studies reveal the second compound to be a ferromagnetically coupled face-sharing d5-d5 system.