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The mechanism of the green luminescence triggered by aromatic hydrocarbons on their association to a beta-cyclodextrin modified with a Tb(super 3+) diethylenetriaminepentaacetic acid (DTPA) macrocycle was investigated. Time-resolved emission spectroscopy was used to examine this enhanced luminescence response with biphenyl as the aromatic hydrocarbon. Experimental results showed that excitation energy at the Tb(super 3+) ion appears 12 micros after light is absorbed by biphenyl included within the beta-cyclodextrin cup.

Proton-coupled electron transfer (PCET) is important as a mechanism for charge transfer in many types of systems including materials- and biology-oriented situations. Areas where transfer of an electron and proton is tightly coupled have been reviewed. Model systems that can provide an experimental basis for a test of PCET theory are of interest. In a PCET reaction, the electron and proton may transfer concertedly (ETPT) or consecutively (ET/PT), and for both kinds of transfers rate constants have been found. To evaluate the rate constants dielectric continuum theory is used. Electron donor hydrogen-bonded-interface electron-acceptor systems displaying PCET reactivity have been studied.

A comparative study of electron transfer via an asymmetric salt bridge interface, formed through the 1:1 association of an amidinium to a carboxylate via hydrogen bonds, was undertaken. Laser flash excitation prompted electron transfer from a highly reducing excited state of a derivatized Ru(II) bipyridine donor complex, to a dinitrobenzene acceptor. Electron transfer rates through the D-(amidinium-carboxylate)-A salt bridge is 10super2 times slower than a switched interface pair.

The magnetic characteristics of the layered vanadyl phosphonates (LVPs) VO(O3PC6H4-X)*nH2O (X = p-NO2, m-F, p-Cl, p-F, H, p-CH3) were studied. The simple paramagnetism of the LVP featuring the strong electron withdrawing substituent X = p-NO2 gives way to increasing antiferromagnetic coupling between the V(super IV) centers as the electron-donating capability if X is increased. Findings revealed that magnetic coupling correlates with a simple measure of electronic perturbation of the exchange pathway in LVPs.

The Charles Drew Enrichment Science Laboratory is a comprehensive program at Michigan State University designed to encourage minority students to complete science and engineering degree programs. Drew Lab begins by identifying potential in high school students, involves counseling and additional instruction while the students still participate in classes with other students, has a research component, is supported by professional and scholarly organizations and involves continuous assessment and support. The main resource needed is the skills and time of the faculty and staff.

The quadruply bonded metal-metal complexes cis-Mo2Cl2(6-mhp)2(PR3)2 (R3=Et3, Me3, Me2Ph, MePh2; 6-mhp=2-hydroxy-6-methylpyridinato) photoreact when irradiated with visible and near-ultraviolet light. The primary photoprocess produces the ligand redistribution products Mo2Cl3(6-mhp)(PR3)3 and Mo2Cl(6-mhp)3(PR3). The photolysis reaction of Mo2Cl2(6-mhp)2(PR3)2 is strongly solvent-dependent. In the absence of light, THF solutions of the photoproducts back-react to produce starting complex. The ligand redistribution photochemistry occurs at wavelengths that are coincident with previously assigned ligand-to-metal charge transfer excited states.

The photoinduced bimolecular reaction of cytochrome c in its reduced and oxidized states with electronically excited Ru(II) diimine complexes is investigated for its driving-force dependence. Variations in the excited state oxidation and reduction potentials that control the driving force of the reaction are made possible by systematically varying the substituents of the parent ligand or by utilizing the mixed-ligand complexes. Results indicate inverted region behavior for the forward bimolecular electron transfer reaction of FeII and FeIII cytochrome c.

The photoreaction of quadruple metal-metal bonded complexes, M2Cl4(dppm)2 with disulfides in nonaqueous solvents generate M(III)(sub 2) edge sharing bioctahedrons Mo2Cl5(dppm)2(SPh) and W9Cl4(dppm)2(SPh)2 respectively. Transition absorption spectra and wavelength dependence of M2X4(dppm)2 indicate that metal-localized activated states present in the higher energy states of delta-delta* state induce the reactivity. The wavelength dependence of M2X4(dppm)2 is associated with the existence of long-lived intermediates.

The excited state chemistry of singly bonded dirhodium complexes were investigated. The compounds included Rh(super 0)(sub 2), RhoRhIIX2 and Rh(super II)(sub 2)X4 cores coordinated by three bis(dilfluorophosphino)methylamine ligands. The results showed that luminescence spectra, excitation profiles and lifetimes are characteristic of dsigma* excited state. The excited state dynamics of the complexes were also found to be influenced by the thermal population of the spin-orbit excited states of a 3(dpi*dsigma*) manifold.

A simple ligand substitution reaction produces quadruply bonded metal-metal complex tetrakis (diphenyl phosphato) dimolybdenum(II, II). X-ray diffraction determines the crystal structures. This complex photochemically reduces 1,2-dichloroalkanes and 1,2-dichloroalkenes which is similar to electroreduction. A Mo(super II) Mo(super III) mixed-valence binuclear complex is produced in the photoreduction reaction.

A cyclodextrin functionalized with a europium(3) (Eu3+)-containing 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane crown ether represents a new series of synthesized supramolecular structures exhibiting photophysical properties. The Eu3+-crown-swing-modified cyclodextrin features luminescence properties similar to simple Eu3+ aza crown swing ethers. Moreover, the supramolecular structures undergo absorption-energy-transfer-emission reaction upon the addition of benzene which results in the increased release of Eu3+ ions.

A quadruply bonded dimolybdenum core was incorporated into layered vanadium and niobium phosphates via the redox intercalation of the dimolybdenum core following acetonitrile solvation and the ion-exchange reaction following NaBH4-reduction of the phosphate layer. The formed layers were studied using absorption spectroscopy, magnetic susceptibility and electron paramagnetic resonance measurements. The results indicated that antiferromagnetically coupled electrons comprised the layered structure resulting in weak exchange interaction coupling.

Intervalence charge transfer (IVCT) is sensitive to the intervening bridge of the redox termini and hence the bridge is typically a ligand that connects one-electron disparate metal ions. The IVCT depends on the position of the central metal between redox termini, which is also unique inasmuch as they are ligand-based and derive their mixed valency from two-electron inequivalency.

Research has been conducted on the tyrosyl radicals. The authors describe the method for the radicals' unmolecular photochemical generation from the diaryl oxalate ester platform on the nanosecond time scale.

Research has been conducted on the one-dimensional extended systems. The use of the disparate synthetic approaches in producing a [Rh (super)I (sub)2 ...Ag (super)I ...Rh (super)I (sub)2] (sub)n (super)5+ one-dimensional chain is reported.