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The trans-[RuS[O.sub.4][(N[H.sub.3]).sub.4](L)]Cl complexes, (L = nicotinamide (nia), L-histidine (L-hist), 4-picoline (4-pic), 4-chloropyridine (4-Clpy), isonicotinamide (isn), pyrazine (pyz), 4-aminopyridine (4-N[H.sub.2]py), 4-cyanopyridine (4-CNpy), pyridine (py), imidazole (Him), and water ([H.sub.2]O)), were characterized by elemental analysis cyclic voltammetry, UV-vis, IR, and electron paramagnetic resonance spectroscopies. From the four v (S[O.sup.2-.sub. 4]) observed only [v.sub.3] and [v.sub.4] split in two bands each for the sulfate unidentate coordination. The values of [DELTA]/[xi] parameters, extracted from g values, allow us to write the following order of increasing [pi]-donation ability: pyz < (py, 4-CNpy, 4-Clpy. 4-pic, isn, nia) < Him < L-hist < 4-N[H.sub.2]py. The intense absorption in the 317-347 nm ([epsilon] ~ 2.3-5.6 x [10.sup.3] [M.sup.-1] [cm.sup.-1]) region was tentatively assigned to sulfate-to-metal charge transfer (LMCT) and the absorption in the range of 230-270 nm ([epsilon] ~ 2 - 6 x [10.sup.3] [M.sup.-1] [cm.sup.-]) assigned to an internal (IL) [pi]-[[pi].sup.*] transition in the heterocyclic ligands. The rate for the sulfate aquation in trans-[[RuS[O.sub.4][(N[H.sub.3]).sub.4]L].sup.0] complexes was evaluated through chronopotentiometric measurements and are in the 2.6 [s.sup.-1] (chloropyridine) to 20 [s.sup.-1] (pyrazine) range. The S[O.sup.2-.sub.4] is aquated in trans-[[Ru.sup.III]S[O.sub.4][(N [H.sub.3]).sub.4](4-pic)]Cl at the specific rate constant of (1.4 [+ or -] 0.4) x [10.sup.-5] [s.sup.-1], which is very much slower than in trans-[[Ru.sup.II]S[O.sub.4][(N[H.sub.3]).sub.4](4-pic)] (5.4 [s.sup.-1]). The X-ray crystal structure data show that the Ru--Cl (2.3444(9) [Angstrom]) and Ru--N[H.sub.3] (2.100(2) [Angstrom]) mean distances in trans-[RuCl[(N[H.sub.3]).sub.4](4-pic)][Cl.sub.2]* [H.sub.2]O are similar to the ones observed in other tetraammineruthenium(III) complexes. Key words: ruthenium, sulfate, ammines.

Research describes the physico-chemical characteristics of heterocyclic monodentate nitrogen ligands in relation to ruthenium complexes and their fluxionl behaviors in solution by using (sup)1H nuclear magnetic resonance spectroscopy. Data indicate that different ruthenium complexes have different fluxional behaviors in solution and the smallest ligand exhibits the fastest exchange kinetics.

A spectroscopic comparison of the structure of amorphous PcRu (1) with that of the bisubstituted monomer PcRu(n-BuNH2)2 (2) has been carried out to prove the existence of short Ru-Ru double bond in 1. Compound 2 was chosen for the EXAFS spectroscopic study because it does not have the short Ru-Ru bond during ligand attachment. Results show that the next-neighboring phthalocyanine molecule is located at a shorter distance in 1. N-butamine ligands are found at one side of the macrocycle at a long distance in 2.

The formation of ruthenium metal centers with varying distances can be attributed to the series of bimetallic complexes of ruthenium(II) which are bridged by heterocyclic ligands that are formed through the condensation of metal derivatives such as diamines, hydrazine, benzidine and 4,4'-nethylenedianiline. These complexes also feature the metal-to-ligand charge-transfer absorptions in the 450 nm region. The heterocyclic ligands which bridged ruthenium(II) are oxidized through electron processes.

The formation of ruthenium nitrosyl complexes by reacting Ru(bpy)(CO)2Cl2 with Ru(4,4'-dmbpy)(CO)2Cl2 and Ru(6,6'-dmbpy)(CO)2Cl2 in oxidizing acidic solutions was investigated. The carbonyl ligands in Ru(bpy)(CO)2Cl2 and its methyl-substituted derivatives have been replaced by NO and Cl ligands in HCl/HNO3 solution. The Ru(4,4'-dmbpy)(CO)2Cl2, on the other hand, formed Ru(dcbpy)Cl3(NO). The substitution of the 2,2'-bipyridine ligand by 6,6'-dimethylbipyridine caused the splitting of Ru(6,6'-dmbpy)(CO)2Cl2 into (H3O)2{Ru(NO)Cl5 and 6,6'-dicarboxy-2,2'-bipyridine hydrochloride.

The intrinsic charge localization in the formed state of metal-to-ligand charge transfer (MLCT) excited-state formation was established through utilization of Electronic Starck effect measurements. Data indicated that the transition involved the production of a charge-localized state. It was further indicated that the 'singlet' MLCT excited state of Ru(phenanthroline)3(super)2+ resembled the MLCT state of the bipyridine analogue.

A novel method of synthesizing ruthenium(II) complexes with unsymmetrical terdentate ligands was developed. The design featured the utilization of Friedlander condensation between 8-amino-7-quinolinecarbaldehyde and a ketone. Results have shown that the different coordination modes indicated that subtle steric and electronic considerations can determine the stereochemistry of binding.

Chemical and electrochemical studies were conducted to investigate the ruthenium complexes of a mono-(thiosemicarbazone) of 2,6-diacetylpyridine. It was shown that 2,6-diacetylpyridine reacted with 4-(4-tolyl) thiosemicarbazide resulting in the formation of bis(thiosemicarbazone) and mono(thiosemicarbazone). The reaction of the ligand L(sub 2)H with Ru(PPh(sub 3)(sub 3)Cl(sub 2)) resulted in various products was determined by the nature of the reaction medium. In an ethanol medium, the product isolated was [Ru(L(sub2))(PPh(sub3))(sub2)]X where X = ClO(sub4), Cl; while acetonitrile medium, the compounds behaved as uni-univalent electrolytes.

Ruthenium half-sandwich complexes of thoiethers can be directly oxidized to the corresponding sulfoxide complexes using dimethyldioxirane (DMD) which acted as a strong and selective oxygen transfer reagent. The resulting complexes were characterized as chiral compounds with metal centers that were oxidized with moderate diastereoselectivity. Furthermore, high diastereoselectivities were achieved for complexes that bear the (S,S)-CHIRAPHOS ligand as a chiral auxilliary.

The reaction of omicron-diaminobenzo-15-crown-5 and 1,10-phenanthroline-5,6-dione in alcohol led to the formation of a dypyrido[3,2-a:2',3'-c]phenazo-15-crown-5 (dppzc) ligand. The ruthenium(II)-dppzc complexes in acetonitrile exhibited high spectral emission intensity due to the blocking of the photo-induced electron transfer quenching mechanism during cation inclusion. Furthermore, the spectator ligands exhibited negligible effects on the crown ligand and did not alter binding ability.

The novel scanning force microscopy (SFM)-based assay for weakly-binding ligands was utilized to determine the molecular characteristics of DNA-ligand interactions. The novel SFM assay can be utilized as an alternative strategy for the high-precision analysis of the length of single DNA molecules. The novel assay was also used for confirming the absence of DNA sequence lengthening during interactions with Ru(phen)sub2sup3+.

Di- and trinuclear ruthenium(II) complexes of the 'Chiragen' ligand series were synthesized. The results revealed that the reaction of the ligands with Ru(bpy)2Cl2 generates a mixture of diastereomers whereas the use of enantiomerically pure delta- or lamda-(Ru(bpy)2(py)2)(dibenzoyltartrate) or delta-Ru(CG(m-xyl))Cl2 yield products of nearly complete stereoselectivity. The results of a circular dichroism study also showed that the complexes consist of one helical diastereomer with the expected absolute configuration predetermined by the chiral building block used. C2 point group symmetry was the observed configuration of the structures.

X-ray crystallography and nuclear magnetic resonance spectroscopy were done to characterize the (RuTp(pn))+ fragment. It was found that the fragment has a strong sigma acceptor and a weak pi donor through which reversible complexes with a variety of sigma donor ligands such as dinitrogen, water, acetone, CO and vinylidene, can be formed. Theoretical calculations and crystallographic data revealed that the order of increasing stabilities of the (TpRu(pn)L)+ complexes with respect to the ligands are CF3SO3- < acetone or water < CH3CN < N2 < CO < vinylidene.

The crystal structure of [Ru2Cl3(tacn)2]2+, [Ru2Br3(tacn)2]3+ and [Ru2I3(tacn)2]3+ were analyzed by Raman spectroscopy to determine the mechanims that affect their steric interactions. The tridentate tacn ligands of the ruthenium blue complexes exhibited higher steric hindrance compared to the unidentate NH3 ligands. Furthermore, steric hindrance between the hydrogen and alpha-carbons of the tacn and halide bridges of the ligands increases the Ru-X-Ru bond angles.

Analysis of the physical and photophysical properties of monometallic and bimetallic Ru(II) complexes indicate the presence of metal-to-ligand charge transfer interactions. The two bipyridine moieties of the compounds exhibit different attachments in the six or four positions. Furthermore, attachment of the bipyridine moieties to the six position causes steric hindrance. The number of diimine ligands in the Ru(II) complexes also affects the absorption coefficients of the pi-pi* bond transitions.

Ruthenium complexes such as [RusupIIIsub3(mu3-O)(mu-CH3CO2)6(mbpy+)2(L)3+ and [RusupIIIsub2RuII(mu3-O)(mu-CH3CO2)6(mbpy+)2(CO)]2+ were analyzed to determine the mechanisms of terminal ligand-ligand reactions. The two mbpy+ ligands of the mbpy+-coordinated Ru3 complexes exhibited ligand-ligand interactions due to the presence of pi-pi electronic coupling. The interactions between the RuIII...RIII units are also dominant in the triruthenium complex.

The reaction of olefinic alcohols with 1,2-bis(phosphino)ethane in a free-radical environment produced hydroxybutyl and hydroxypentyl homologs of 1,2-bis(bis(hydroxymethyl)phosphino)ethane. The synthesis of the 1,2-bis(bis(hydroxyalkyl)phosphino)ethane ligands is characterized by the free radical addition of 1,2-bis(phosphino)ethane to 3-buten-1-ol(Aldrich) olefin alcohol. Furthermore, the ligands react with Ni(II), Ru(III), and Rh(I) to form transition metal complexes that exhibit water solubility.

The reaction of bis(diazonium) salts with the hydride species MH2P4 and (MH(4-CH3C6H4CN)P4)BPh4 in a 2:1 ratio at low temperature afforded binuclear complexes ((MHP4)2(mu-HN=NAr-ArN=NH))(BPh4)2 and ((M(4-CH3C6H4-CN)P4)2(mu-HN=NAr-ArN=NH))(BPh4)4, respectively. NMR and IR spectroscopy and an X-ray crystal structure determination were conducted to characterize the compounds.

The Friedlander condensation of 8-amino-7-quinolinecarbaldehyde with 5,6,7,8-tetrahydro-8-quinolone resulted in the formation of the dipyridol derivative, 1,2-dihydrodipyrido[4,3-b;5,6-b]acridine. The ruthenium(II) ligand has a saturated half that is derived from the ruthenium(II) complex and an unsaturated region that is derived from dipyrido[4,3-b;5,6-b]acridine. The H7 proton of the ligand is sensitive to high unsaturation levels with a chemical downfield shift of 0.58 ppm.

The oligomeric Ru2(O2C(CH2)6CH3)4 and its Rhsub2super4+ analogue exhibit extended pi-systems in noncoordinating solvents. The axial ligands of dimetal tetracarboxylate systems are affected by dipolar and contact shifts. The presence of direct pi-delocalization in pi-type ligands indicates the formation of conductive polymers through bridging pi-type ligands. This link connects Ru2(o2CR)sub4supern+ units in dimetal tetracarboxylate systems. Downfield sigma-contact contributions occur due to the chemical shifts on axial THF ligands and equatorial carboxylate ligands.

The addition of sulfur dioxide, acetonitrile, and tert-butyl isocyanide to octahedrally coordinated bis(ether-phosphine)ruthenium(II) complexes (1a-c) generate eta1(P)-coordinated ether phosphine, Cl2Ru(CH3CN)(P-O)(P-O). The facile cleavage of Ru-O bond activate small molecules such as phenylacetylene, sulfur dioxide, CO, CS2 and tert-butyl isocyanide. The feasibility of Ru-O bond depends upon the donor strength of phosphine and the O-basicity. The vinylidene complexes exhibit exchange phenomena in a two step procedure. Syntheses of these complexes are discussed.

Two tetranuclear ruthenium (II) complexes are synthesised and their structures are analyzed with electrospray ionization mass spectroscopy (ESI-MS). The cation (M-5X)5+ (M = molecule, X = ClO4-), has a coordination between three ClO4- and the metal bearing ligands. Steric hindrance in the pyridine ring makes a distorted planar form in the first compound, which has no protonated site.

3,3',5,5'-tetrapyridylbiphenyl (tpbpH2) is a bis-cyclometalating terpyridine bridging ligand that strongly couples mixed valence, ruthenium and osmium metal centers. Physical properties of the dinuclear Ru and Os systems are studied using electrochemical and spectroscopic data. Ru complex exhibits diamagnetism over a large temperature range. Electronic coupling strength between metal centers varies with ligand nature and the distance between metals.

2-(2'-pyridyl)Pyrimidine (PYPM) and bis(pyridine) complexes are used to design more complex systems based on pyridine binding to ruthenium(II)(Ru(II)) by focussing on the energy gap between the MLCT state and ground state. The minimization of low lying dd states is studied for the molecular level factors that cause it. Ligand combinations that minimize photochemical loss are identified to enable preparation of photostable light induced electron-transfer systems with the Ru(II) complexes as the system cores.

Synthesized mixed-metal compounds of the general form ((bpy)2Os(BL)Ru(bpy)2)4+, where BL indicates the bridging ligands and dpp, dpb, and dpq indicate tpy, are studied for their spectroscopic electrochemical and spectroelectrochemical properties. A study of the electronic absorption spectra indicates a lowest energy transition Pi-Pi to the red on variation of the BL from dppt to dpq to apb. Spectroelectrochemistry confirms the assignment of the lowest energy transition levels with the first and second bimetallic complex reductions being attributed to the sequential bridging ligand reductions.

High yields of [RuH(SiHPh2)(CO)L2 were synthesized by the C6H6 elimination reaction of Ru(H)Ph(CO)L2 with H2SiPh2 and toluene. Complex facile exchange of the RuH and SiH units of [RuH(SiHPh2)(CO)L2 was detected at 25 degrees centigrade due to oxidative addition of the hydrogen substituent and reduction of the eta3-silane complex. Reductive elimination reactions were also detected in the saturated RuIV trihydride species due to the absence of pi-donor ligands.

[Ru6(CO)13(mu-CO)(mu3-NH)(mu5-N)(mu3-OMe){mu2-eta2-C(O)OMe}2] and [Ru4-(CO)12(mu4-N)(mu-OMe)] were produced when a n-octane solution of first hexanuclear ruthenium carbonyl product was heated under reflux. The hexanuclear ruthenium carbonyl cluster has a distorted square-pyramidal geometry that is composed of a Ru5(mu5-N) metal core with an Ru atom that is capped by bridging organic moieties on one triruthenium plane. The basal triruthenium plane exhibits a trapezoidal geometry.

A tridenate bis-amide ligand 2,6-bis(N-phenylcarbamoyl)pyridine (H(sub 2)L) used, in its deprotonated form, a new mononuclear ruthenium(III) complex [Et(sub 4)N][RuL(sub 2)].H(sub 2)O (1) is synthesized. The structural analysis of the same, is revealed.

Infrared spectroelectrochemistry of the oxidation states of the hexaruthenium clusters, with pyrazine-d(sub)4 as bridging ligand, shows oxidation-dependent spectral changes. Further, a symmetric vibrational mode of pyrazine is seen for four pyrazine-bridged hexaruthenium mixed-valence complexes exhibiting electronic coupling between clusters.

The organoruthenium complex [Ru(H2O)((R)-bpop)(C6H6)(BF4)2 was produced in 77% yield by the removal of [RuCl((R)-bpop)(C6H6)]BF4 with AgBF4 in H2O. The ruthenium complex has one set of oxazoline ring proton resonances and one resonance for its center methyl units of (R)-bpop. The complex is a solid-state structure without C2 symmetry. Furthermore, it also exhibits an H2O associative exchange or a unimolecular dissociative reaction during the intraconversion process.

The [OEP]Ru(NO)(H2O)+ cation is a stable precursor to diamagnetic nitrosyl porphyrins that contains ligands of nitrosamine, thiolate and amine. An 81% yield of nitrosyl thiolate can be obtained by combining alkane- and arenethiolate anions. The nitrosyl thiolate cationic complex is air-stable and generates iron nitrosyl porphyrin derivatives. Bis-nitrosamine complexes of iron porphyrins can be synthesized to produce derivatives of ruthenium porphyrins.