Triplet excited states photophysical properties

The photophysical properties of 1-8 have been studied in different solvents (PhMe, CH2CI2, and CH3CN). The lifetimes of the lowest triplet excited states are summarized in Table 1. 

Fullerene Ceo is an electron-deficient compound with rich photophysical and photochemical properties. Moreover, the triplet-excited state of Ceo is formed almost quantitatively and, in the presence of molecular oxygen, energy transfer from the triplet-excited... 

The effect of aggregation or interchain interaction on the triplet excited state in Pt-acetylide polymers was investigated by comparing the optical properties of 1 with the pentiptycene-bridged polymer 15.21 The interchain interaction is prevented by the sterically demanding pentiptycene moiety in 15, and its photophysics is being dominated by the intrachain triplet exciton. 

The compounds [M(bpy)3][SeCN]3 (M = Ce, Pr, Nd, Tb, Dy, Ho, or Er) have been prepared by the reaction of M(SeCN)3 with bpy (307, 849). Conductivity studies of solutions of the compounds, together with infrared and crystallographic studies of the solids, suggested that a 6-coordinate formulation was appropriate. The ground-state magnetic properties and photophysical properties of the triplet excited states of [M(bipy) ] + complexes (M = Pr, Nd, Tb, Dy, or Er n = 3 or 4) have been reported (872). The complexes are prepared by the reaction of the appropriae metal perchlorates with bpy in ethanol. 

The photophysical properties of individual molecules under a wide variety of conditions are currently attracting considerable interest. Spatial photoselection of single molecules on surfaces has been reported (Watson et al. and Lemer et al.) and the importance of the triplet excited state for single molecule detection has been emphasised by Kilin et al. and Brouwer et al. 

Interestingly, imides possess a photochemical behavior that is very similar to that of ketones. Especially, phthalimides behave like phenyl ketones with respect to some of their photophysical properties. Despite many similarities there are at least three important differences. First, phthalimides are more prone to photoelectron transfer (PET) processes than ketones. This property was very successfully applied in the synthesis of a variety of amino acid derivatives (see Section 6.2.3.2). Second, the cyclization of imides often affords 0,7V-acetals as primary products, and this obviously has some consequences for the stability and the follow-up reactions of these products. Third, in contrast to aryl ketones, phthalimides are not quantitatively converted into the triplet state, and thus they may react both from the singlet and the triplet excited state. 

A new peptidic Au(i)-metalloamphiphile able to self-assemble into micellar nanostructures of 14 nm in diameter shows interesting photophysical properties. In particular, the luminescence of these species can be assigned to electronic transitions from triplet-excited states with excited state life times of 1.5 ps. ... 

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