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Research has been conducted on the diionized and monoionized aromatic diols. The isolation, characterization and structural analysis of these compounds incorporating achiral and chiral alpha-amino acid salicylaldimines have been carried out and investigated and the results are reported.

Research discusses rhenium-promoted ligand oxidations and documents one to two oxygen atoms transfer between the azopyridine and diphosphine reagents. Data indicate that the transfer results in mononuclear and binuclear products, respectively.

The structural characterization and solution thermodynamic properties of iron complexes of two of the heteropodans ligands, based on hydroxypyridinonate (HOPO) and other ligands, that are therapeutic agents for ferric ion sequestration are reported. The ligands that are described are part of a new class of heteropodate ligands, which exploit the various chelating properties of several binding units within a single tripodal ligand and allow for systematic variation of the properties for medical or other applications.

The reaction of the dihydride [Ru(super II)(H)(sub 2)(CO)(PPh3)(sub 3)] with excess azo-2,2'-bipyridine (abp) in boiling dry benzene has afforded the diradical bischelate [Ru(super II)(abp(super .-))(sub 2)(CO)(PPH3)] and the hydridic monochelate monoradical [Ru(super II)(abp(super .-))(H)(CO)(PPH3)(sub 2)]. The diradical bischelate displays strong metal-mediated antiferromagnetism, and upon oxidation to the monoradical the unpaired electron with approximately 40 percent azo pi(super star)-character gets localized in one of the chelate rings.

Research has been conducted on the reducible ligands azopyridines to investigate osmium. Isolation of nonradical congeners formed via electrochemical/chemical oxidation is discussed.

A study concerning the synthesis and the structure of the rhenium-azopyridine system is described. The effect of azopyridine pi-acidity on metal reduction potential is analyzed.

A study concerning the synthesis of the (pyridylazo)oxime ligand to promote a mononuclear oximato-O coordination is presented. Experiments include hydrazone nitrosation.

The synthesis of the glycosides methyl-2,6-dimethoxy-beta-D-galactopyranoside, methyl-4,6-dimethoxy-alpha-D-mannopyranoside, and methyl-5-methoxy-beta-D-ribofuranoside is described. The reaction of these glycosides with VO(L-Asal)(OMe)(OHMe) in dichloromethane results in esters of the type VO[beta-D-HMe(sub 3)MP](OHMe), and VO[beta-D-HMe(sub 2)RF](L-Asal) as dark-colored solids. The X-ray structures of two representative esters are determined, confirming the induction of chiral specificity at the metal site by ligands.

Research was conducted to examine the synthesis, structure and chemical reactions of a family of (N-salicylidene-alpha-amino acidato)vanadate esters incorporating chelate propane-1,3-diol and glycerol. V(super V)O(Asal)(Hpd) and V(super V)O(Asal)(H2p) were synthesized in excellent yields through the reaction of V(IV)O(Asal)(H2O) with propane-1,3-diol(H2pd) and glycerol (H3pt), respectively, in methanol. Results indicate that the chelate rings are conserved in solution and glycerol does not form the six-membered ring at all.

A family of picolinamide complexes which included the rare Re(super VI)NAr moiety was successfully synthesized by treating pyridine-2-carboxaldimine chelates of Re(super V)NAr with nitric acid. The 2-benzoylpyridine complex failed to transform from imine to amide due to the steric crowing of the phenyl substituents. The transformation, on the other hand, was facile in the case of the pyridine-2-carboxaldehyde and 2-acetylpyridine.

X-ray crystallography and electrochemical studies were done to characterize the newly synthesized triad of variable-valent rhenium aldimine and amide systems, Re(super V)OCl3(RA) (complex 1), Re(III)(OPPh3)Cl3(RA) (complex 2) and Re(super IV)(OPPh3)Cl3(RB) (complex 3). The compounds were found to be formed via associative pathways involving nucleophilic attacks of PPh3 on the Re=O and of water on C=N. The compounds were also found to be interrelated in that they are formed in succession through the outward and inward transfer of oxygen atoms.

The one-electron electroreduction of V2O3(L-Asal)2 in dichloromethane yields Et4N(V2O3(L-Asal)2). (L-Asal)2 is the deprotonated salicylaldimine of L-alanine, L-valine or L-phenylalanine. The metal atoms have a distorted square pyramidal geometry. The relative orientation of the two terminal V=O groups is intermediate between cis and trans. The unpaired electron is delocalized and thus the metal valence is over both metal atoms. The complex crystallizes in an orthorhombic space group.

The reaction between RuII(eta-2-RL)(PPh3)2(CO)Cl, where R is Ph, p-MeC6H4, with NaY, where Y is NO2 or NO3, yields two organometallics, RuII(eta 1-RL)(PPh3)2(CO)(eta-2-Y). An associative cis attack by Y- on chloride induces this reaction. The addition of excess halide to the products gives the backward reaction. An iminium-phenolate to imine-phenol tautomerism and a change in the rotational conformation of the RL ligand causes the interconversion of the products. Both products crystallize in monoclinic space groups.

The azo-amine system in the form of electroneutral diamagnetic bis chelates of palladium is presented. The chelated azo amines incorporate 10 ligand pi electrons while their synthetic precursor is the bis(azooximate) Pd-(Ra)2. The azo-amine frame can be looked upon as the intermediate member in the azo-azo, azo-amine, imine-imine sequence. Results with palladium indicate that the chelate frame can sustain more ligand pi electrons and anionic charge as the number of nitrogen increases.

Tridentate ligands H2PhL, H2ToL, and H2NpL react with iron(III) chloride to yield iron(III) salts Et4N(Fe ArL 2). Azo oxime chelation affords spin-pairing while the coordination of the carboxylate effects a stabilized trivalent state. Distinct rhombic spectra are achieved in frozen dimethylformamide-toluene glass, which are in agreement with the cis-FeN4O2 metal coordination geometry. This configuration is generated from meridional binding of the two ligands to the metal through oximato N, azo N, and carboxyl O atom pairs.

Spectroscopic studies of ruthenium complexes of the type RuN4P2 containing the Ru(PPh3)2 moiety reveal the presence of an intense near-IR LMCT band. The voltammograms of Ru(II) and Ru(III) are identical due to their invariant geometry. Crowding by PPh3 and other such functions leads to destabilization of the bi- and trivalent cis geometries. The trans geometry of the bivalent state possess back-bonding, while that of the trivalent state does not.

Synthesis of first low-spin complexes of manganese(II) with thioether binding involves the use of new hexadentate thioether-oxime-azo ligands, which also help prepare iron(II,III) species. Oximato-N coordination exerts significant influence on spin-pairing. X-ray studies of MnS2N4 coordination sphere reveal that the lengths of Mn-S and Mn-N bonds are significantly short. EPR spectroscopic studies reveal that 55Mn EPR hyperfine coupling is weak.

A one-electron-one-proton electroprotic transformation enables the conversion of trans-Pt(pbo)2 (Hpbo = PhN double bond Nc(Ph) double bond NOH), prepared from a reaction between Hpbo and K2PtCl4, into a cis-dimer complex. Both trans and cis complexes exhibit diamagnetism in the solid state, and in solution the dimer undergoes dissociation. X-ray and spectroscopic studies help characterize these complexes. In the dimer, dz2-dz2 and azo-azo interactions exhibit significant contribution to binding, while the unpaired electron in the monomer is significantly azo-pi in nature.

The reaction of bis(salicylaldimines) (H2sxL) with cobalt(II) acetate tetrahydrate and sodium perchlorate produces two complexes (Co(III)(sxL))ClO4 (x = 2 and x = 3). Sodium hydroxide induces deprotonation of salicylaldimine ligands in the two complexes, generating two new complexes. In one complex (x = 2) C-S cleavage occurs, followed by thiolato-bridge formation of a new complex. In the second complex (x = 3) metal binding moves from the thioether to the adjacent carbanionic site, leading to ring-size-specific transformations. NMR studies help characterize all the four complexes.

Hydrogen peroxide oxidizes cobalt(II) acetate tetrahydride to form a dithiaalkyl-substituted triazene oxide compound, (Co(III))(Me(x)L)ClO4CH2Cl2. The ligands behave in a hexadentate manner in these complexes as the coordination spheres are the CoS2CH2Cl2 type. The cleavage of the coordinate constituents by a scission bond occurs when Co(Me2L)+ reacts with a base.

MnIII(RxL)y was electrochemically prepared after having obtained MnII(RxL) from the reaction of manganese(II) acetate tetrahydrate with dithiaalkyl-substituted triazene 1-oxides. Octahedral MnS2N2O2 coordination spheres result as the ligand functions in a hexadentate manner in every instance.

Oxo-vanadium complexes which incorporate oxygen and nitrogen donor ligands are synthesized and characterized. Binuclear oxovandium complexes are synthesized by the aerial reaction between dihydroxyazobenzene and bis(acelylacetanoto)oxovanadium in methanol medium. The complexes are characterized by electronic and infra-red spectra.

Trinuclear complex CuIIFeII2(RL)6 results from the reaction of the tris(arylazo oximato)iron(II) anion, Fe(RL)3- (R = Me, Ph, p-MeC6H4) with Cu(MeCN)4+ in dichloro methane, under air. The binuclear complex CuIFeII(RL)3(PPh3) is isolated in the presence of PPh3. CuFe(MeL)3(PPh3) and CuFe2(PhL)6.2CH2Cl2 are studied for their X-ray structures. The Fe(RL)3- portion serves as a facially disposed tridentate oximato-O3 ligand, in both complexes. The presence of a soft coligand such as PPh3 facilitates stable binding of copper(I).

The deprotonated forms of N-(2-hydroxyphenyl)salicylaldimine (H2amp),2, 2'-dihydroxyazobenzene (H2azp), N-(2-carboxyphenyl)salicylaldimine (H2amc) or 2-hydroxy-2'-carboxy-5-methylazobenzene (H2azc) are seen in the ONO ligands of the (V(V)O(ONO))(ON) and V(IV)O(ONO)(NN) groups. The deprotonated form of 8-quinolinol (Hhq) is an ON ligand while 2,2'-bipyridine (bpy) or 1, 10-phenanthroline (phen) forms the NN ligands. Aerial oxygen is used as an oxidant when V(IV)O(amp)(bpy) or V(V)O(amp)(hq) are formed due to the interaction of VO(acac)2 with H2amp and pby or Hhq in methanol.

Two geometrical isomers of (OsL2(PPh3)2)PF6.nH2O, a green (1) and red one (2), were obtained from the oxidation of OsL2(PPh3)2 by cerium(IV). Complex 1 was formed on a large proportion compared to 2 which constituted only about 1 percent. Complex 1 consisted of cations of single type with the atoms occupying general positions while 2 had two almost identical cations. The donor pair triad (N,N)-(S,S)-(P,P) was cis-cis-trans in 1 and trans-trans-trans in 2. The reduction potentials and distortion parameters of the complexes were compared.

A group of Mn(RQ)3(super z) complexes, where R = Cl, Br, Me and (super t)Bu and z = 1- or 0, was synthesized and characterized. The reaction of HRQ with Mn(III) acetate in methanol resulted in Mn(super III)(RQ)3., while reaction with Mn(II) salts resulted in a mixture of species. The Mn(RQ)3(super z) group is characterized by chelating ligands which allow low-spin complexes for the metal in the di- and trivalent states. Moreover, a low-spin trivalent state exists in a nonporphyrinic O,N environment. Finally, a tris chelate geometrical isomerism also exists for the di-and trivalent states.

The tris(thioxanthate)nickel(II) salt Et4NNi(txn)3 is generated by the reaction of potassium ethylthioxanthate with Ni(II) chloride hexahydrate. This salt forms the trithiocarbonate (Et4N)2(Ni2 SEt 2 CS3 2) when dissolved in acetone. Its structure is reported to be a = 31.279(9) Angstrom (A), b = 13.670(5) A, c = 16.900(4) A, beta = 102.63(2) degrees, V = 7050(4) A(super 3), R = 0.0733, R(sub w) = 0.0720, Z = 8 and space group C2/c. The metal atoms of the salt are chelated by a trithiocarbonate dianion, resulting in a planar, four-membered NiS2C ring.

The application of heat in a mixture of ethyl and methyl salicylate with triethylenetetramine for twelve hours results in the formation of 1,8-bis(2-hydroxybenzamido) 3, 6-diazaoctane and 1,10-bis(2-hydroxybenzamido) 4,7-diazadecane hexadentate ligands in 87% and 97% yields, respectively. The two compounds, which incorporate amide, amine and phenol properties, react with Mn(CH3CO2)3.2H2O in aqueous methanol to produce MnN4O2-containing MnL2.4H2O and MnL3.MeOH complexes. These complexes exhibit a 3d3 configuration with axial x-band EPR spectra. The Mn(IV)-Mn(III) couple shows a low reduction potential which is indicative of its facile oxidation by air.

Catechol groups containing H, 4-t-Bu, 3,5-(t-Bu)2 and 3,4,5,6-Cl4 reacted with tc-(Ru- OH2 2 tap 2)(ClO4)2.H2O to form the respective Ru(RQc)(2- m-tolylazo pyridine) (tap)2. Cerium(IV) oxidation of Ru(RQc)(tap)2 in acetonitrile gave (Ru RQc tap 2)+ which was obtained as the perchlorate salt. The molecular and electronic structures and the redox behavior of the complexes were determined using spectral and electrochemical measurements.

The chemical synthesis of Nickel(III) complexes of coordination type NiS2N4 using acyclic hexadentate thioether-azo-oxime ligands is described. Structural analysis is established given using single crystal X-ray spectroscopy, including selected bond distance and angle measurements. The research achieves the production of NiIII-S(thioether) species incorporating acyclic ligands for the first time.

The effects of variable metal valence on the dimensions and bonding around the M = Ru species were analyzed by utilizing two Ru complexes with a general formula of RuCl2(L)(HL)z (HL = PhC(NOH)NNPh; z = 1-, 0). The ruthenium complexes were synthesized as Et4N+ salts from the reaction of trans-RuCl2(Me2SO)4 with PhC(NOH)NNPh. The RuCl2(L)(HL)z complexes exhibited distorted octahedral geometries with linear RuCl2 fragments. Furthermore, the ruthenium complexes exhibited unsymmetrical O-H-...O hydrogen bonding.

The reaction of Mn-(MeCO2)2.4H2O with the ligand H2ArL produces carboxyl-coordinated Mn complexes with low-spins. The (MnII(ArL)2)2- bivalent complex has a moderately intense charge transfer absorption in the visible region and behaves as an 1:1 electrolyte. The complex contains a five-membered puckered chelate ring that forms a dihedral angle of 16.9 degrees with the phenyl ring. The complex's variable temperature moment decreases with a decrease in temperature. The spin-pairing shortens the metal-radius in the complex.

Synthesis of FeS2N2O2 complex with Fe(III)-S(thioether) binding involves a reaction of iron(III) nitrate nonahydrate with hexadentate triazene 1-oxide thioether ligands. X-ray studies of the complex (Fe(Me3L))ClO4 confirm the presence of Fe(III)-S(thioether) binding. EPR spectroscopic studies reveal the complexes as high-spin complexes. Cyclic voltammetric studies reveal that at low potentials Fe(III) complexes undergo reduction producing Fe(II) complexes.

[Ag(MeL)(HMeL)(sub 2)](sub 2) and [Ag(PhL(HPhL)](sub 2) have resulted from the title azooximes PhNNC(R)NOH, HRL(R = Me, Ph). Strong H...H hydrogen bonds characterize the species while the Ag...Ag distances are shorter and longer than the van der Waals sum in [Ag(PhL(HPhL)](sub 2)and [Ag(MeL)(HMeL)(sub 2)](sub 2).