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The synthesis of a family of iron(II) spin crossover monomers containing the bis-meridional ligands 2-(1-pyridin-2-ylmethyl-1H-pyrazol-3-yl)-pyrazine (picpzpz) and 2-(3-(2-pyridyl)pyrazol-1-ylmethyl)pyridine) (picpypz) is described.

A report is presented on the synthesis of two new derivatives of 1,4,7-triazacyclononate and their use in the preparation of 'roof-shaped' hydroxo-bridged copper(ll) complexes, in which the (Cu2(mu-OH)2)(super 2+) core is asymmetric and the two Cu-tacn moieties adopt a syn configuration across the hydroxo-bridged core. The ability of these complexes to cleave phosphate ester is examined, which has involved the study of the reaction of the complexes with the model phosphate ester, bis(nitrophenyl)phosphate (BNPP).

Human sulfiredoxin (Srx) exhibits a new protein fold and a novel nucleotide binding motif containing the consensus two-Cys peroxiredoxins (Prx). The features and the conformational flexibility of the Prxs suggest that specific interactions are made between human Srx and the typical two-Cys Prxs.

Research has been conducted on the hexacyanometalates used as templates in preparation of heteropolynuclear complexes. The reaction of the pentadentate ligands' metal complexes with heterocyanometalates has been studied and the details are presented.

Research has been conducted on the polyoxometalate anions. The use of decamethylferrocene as a clean chemical reductant in monitoring the products' protonation and redox levels in solution is described and the structure of the alpha-Dawson anions in the diamagnetic reduced forms has been investigated and compared to that in the oxidized reduced forms and the details are reported.

Research has been conducted on the model complexes for the intermediate species in the biological transmission and racemization of the amino acids with the pyridoxal phosphate. The isolation of the single-stranded metal-coordinated polymers from the reaction mixture of Cu(ClO (sub)4) (sub)2, N-(2-hydroxybenzyl)-beta-alanine and 1,10-phenanthroline has been carried out on the hydrogen- and covalent-bonding basis in a solid state and the results are discussed.

Research has been conducted on the Hammett constants effective in describing the effect of the substituents on the chemical reactivity. The ability of the descriptors derived from the quantum mechanical calculations to catch up with the Hammett parameters in correlating chemical phenomena has been investigated and the results are presented.

Anti-inflammatory Cu(II) dimer complexes of indomethacin with axial solvent donor ligands were characterized by electronic, x-band electron paramagnetic resonance and variable temperature magnetic analysis. Results indicated the complexes' relative insensitivity to changes in the axial ligands. Since the axial ligands were likely to exchange during drug metabolism, results showed that the physical properties and reactivities of indomethacin are likely to be insensitive to the nature of axial ligands.

An innovative method to calculate the aqueous solvation energies using only the computed molecular properties of the solute has been developed. The molecular surface electrostatic potentials of the solute are computed via the B3P86/6-31+G** density functional procedure. The results showed a good level of accuracy when the method was applied to calculate the aqueous solvation energies of 50 solutes of various chemical types.

A study was conducted to analyze C-H and C-NO2 dissociation energies in some azines and nitroazines. A density functional process was utilized to carry out the analysis. The C-H and C-NO2 dissociation energies were computed and given in decreasing order. Experimental results indicated that variations within two isomeric groups can be correlated with the relative stabilities of the product radicals.

The structural and the magnetochemical properties of the novel pentanuclear complex, {(Ni(bpm)(sub 2))(sub 3)(Fe(CN)(sub 6))(sub 2)*7H(sub 2)O was determined. Long-range magnetic ordering is observed at a T(sub c) of 23 Kelvin in both crystalline and powder samples. Detailed magnetization data indicated a ferromagnetic phase transition rather than spin-glass formation. Intercluster magnetic interactions determine the H-bonded 7H(sub 2)O moiety.

(Carbido)decaruthenium carbonyl clusters were analyzed by electron spectroscopy, magnetic susceptibility, near infrared and electron paramagnetic resonance spectrometric studies. The results revealed that the the metal cluster compound exhibits properties that are characteristic of high-nuclearity carbonyl clusters in terms of having 'molecular' rather than 'mesometallic' character.

The reaction of Fe(OH)3, 2 equiv of catechol, and equiv of an aqueous base solution produces a binuclear iron(III) complex. The complex is composed of two PPh4+ cations and an anionic binuclear iron(III) core with six oxygen atoms. The complex (pipH)2[Fe2(bipH)4] has an analogous Fe2O2 core with an isomer shift of 0.46 mm. s-1 and a quadrupole splitting of 0.65 mm. s-1. Fe exhibits a magnetic moment of 5.10 muB in (Ph4P)2[Fe2(Cat)4(H2O)2].6H2O. The complex has an isotropic exchange constant of J= 9.7 cm.-1 with a weak antiferromagnetically coupled binucleus and a strong exchange spin system.

Synthesis of a ferromagnetically coupled hexanuclear copper(II) bipyridine complex and an antiferromagnetically coupled mu-carbonato bonded binuclear complex reveals spectral and magnetic properties. Crystal structure of the complexes reveals that a central planar bis(mu-hydroxo) copper(II) bipyridine moiety contains two cis-Cu(bpy)(sub 2) fragments attached to the central Cu atoms in a trans-axial position. Magnetic studies over a variable temperature range and field range reveals that ferromagnetic coupling of the spins on each Cu(II) center occurs, leading to a S = 3 ground state.

Scientists have shown considerable interest in the application of distorted MN2S2 complexes as spectroscopic and structural models for active site coordination environments of a number of metalloproteins. Synthesization of four new 5-formylpyrazole-based thiolato Schiff base nickel(II) complexes has been executed from the corresponding ligands and nickel(II) acetate.

The two-electron redox reactions using several porphyrin complexes and Mn(II) compounds of porphyrins and salicylaldimines lead to the synthesis of oxo-bridged, heterometallic complexes (L)M(III)ORu(IV)(P)OM(III)(L) (M = Fe(III), Cr(III), Mn(III); P is the domain of 5,10,15,20-tetraaryl- porphyrins). The Mossbauer spectral measurements detect the spin-states (S) of the centers of the complexes. The ground state, the spin ladder of energy levels and exchange parameters are detected.

The synthesis and characterization of a rare high-spin manganese thioether complex, Mn( 9 aneN2S)2(ClO4)2 are presented. The complex has been prepared by the reaction of manganese(II) perchlorate with a methanol solution of 1-thia-4,7-diazacyclononane ( 9 -aneN2S). X-ray structure analysis showed that all of the macrocyclic donors are coordinated in a distorted octahedral geometry.

X-ray analysis, magnetic susceptibility measurement, ion spray mass spectrometry and EPR spectroscopy help the structural characterization of a bis(copper (II)) complex of cyclic peptide ascidiacyclamide derived from the ascidian Lissoclinum patella. Cu-Cu distance is 4.43 angstroms and the complex has a CO(sub 3)(super 2-) species. It exhibits weak ferromagnetic coupling and undergoes structural reorganization of the binuclear copper site on dissolution in methanol.

Octanol/water partition coefficients were obtained in relation to solute molecular surface areas and electrostatic potentials. An analysis of the relationship between octanol/water partition coefficient and the measure of local polarity is used to determine the variability of electrostatic potential.

The compound KAlCuF6 consists of copper(II) ion, characterized by a compressed tetragonal coordination geometry of the CuF(sub 6)(super 4-) units, which is elucidated during an analysis of the 2Az square to E square (xz, yx) transition. The measurement of the electronic spectrum of the compound over visible and infrared region forms a part of the application of the study transition. The magnetic behavior and the EPR spectrum are analyzed by the computation of the angular overlap bonding parameters which helps in determining the intensity of magnetic coupling between Cu2+ ions. The Cu2+ ions are chained to each other through the axial fluoride ligands. The experimentally obtained value of coupling constant is consistent with the theoretical value of J = -60 per cm, with the additional feature of CuFCu bridging angle shown to strongly influence this coupling.

The complexation energies of boron trifluoride (BF3) and boron trichloride (BCl3) with ammonia were computed. The Lewis acidities of the boron trihalides increase in the order BF3 is less than BCl3 is less than BBr3. It is suggested that this trend reflects the importance of Lewis base -> BX3 charge transfer in these complexes and the ability to accept the charge, as indicated by charge capacities.

The reaction of the acetato complex LNi4(OH)(CH3O.H.OCH3)(CH3CO2)2 with azide ion resulted in the azido complex LNi4(OH)(CH3O.H.OCH3)(N3)2(H2O)2. Its reaction with KOH or NR4OH in methanol also generated the solvated methoxo compound LNi4(OH)(CH3O.H.OCH3)3. The cation (LNi4(OH)(CH3O.H.OCH3))2+ remained intact in the complexes which possessed a bowl-like molecular structure. The azido complex contained LNI4(OH)(CH3O.H.OCH3)(N3)2(H2O)2 molecules with no lattice solvent. The methoxo complex exhibited a more dished configuration than either of the acetato and azido complexes.

The u-carbonato u-hydroxo complex (tren)Cr(u-CO3)(u-OH)Cr(tren)(ClO4)3.2H2O crystallizes in the monoclinic space group P2(sub 1)/c with a = 7.022(1) Angstrom (A), b = 25.679(8) A, c = 8.646(2) A, beta = 102.27(2) degrees, V = 1523.4(7) A(super 3), Z = 2, R = 0.054 and R(sub w) = 0.043. The two Cr(III) centers are bridged by one carbonato and one hydroxo group. Nitrogen atoms from the ligand result in a distorted octahedral geometry. Magnetic susceptibility determination indicates that the chromium centers are weakly antiferromagnetically coupled with J = -16.8 centimeter(super -1).

The reaction force F[R.sub.c] is analysed for an [S.sub.N] substitution reaction in the gas and aqueous phases. The preparative structural factors ([E.sub.act,tras]) are least affected but overall forward and reverse activation barriers are significantly lowered by the solvent and this example shows how the reaction force decomposition of activation barriers can help to elucidate the roles played by external factors.

The correlation between lattice energies and surface electrostatic potentials and areas of an ionic crystal was investigated. The lattice energy reflects the electrostatic forces within the three-dimensional array of positive and negative ions. It was found that the lattice energies of ammonium, sodium and potassium salts can be expressed analytically as a function of the total charges of the anions and their computed surface electrostatic potentials and areas.

The electronic switching properties of the nanoporous spin crossover framework (SCOF-2) are rationally manipulated via sorption of a range of molecular guests into the 1-D channels of this material. The changes to the spin crossover properties are related directly to the steric and electronic affect of the individual guests, where the degree of lattice cooperativity is affected by the presence of cooperative host-guest interactions.

The nanoporous metal-organic framework [Fe(pz)Ni[(CN).sub.4]], (pz = pyrazine) which exhibit hysteretic spin-crossover at ambient conditions and is robust to the adsorption and desorption of a wide range of small molecular guests, both gases ([N.sub.2], [O.sub.2], C[O.sub.2]) and vapors (methanol, ethanol, acetone, acetonitrile, and toluene) is described. Guest desorption followed by adsorption, and vice versa, could be used to switch between spin states in the bistable temperature region to add a guest-dependent memory effect to this system.

The structural and magnetic characterization of the new SCOF material Fe[(bpe).sub.2][(NCS).sub.2].3(acetone) (SCOF-4(Ac) and bpe = 1,2-bis(4'-pyridyl)ethane), which has displayed a two-step spin crossover (SCO) that is sensitive to the presence of the acetone guest molecules is presented. The studies have disclosed a series of intricate structural phase transitions associated with not only the SCO properties but also desorption and resorption of the acetone guest species.