Abstract
We report upon an analysis of the vibrational modes that couple and drive the state-to-state electronic transfer branching ratios in a model donor-bridge-acceptor system consisting of a phenothiazine-based donor linked to a naphthalene-monoimide acceptor via a platinum-acetylide bridging unit. Our analysis is based upon an iterative Lanczos search algorithm that finds superpositions of vibronic modes that optimize the electron/nuclear coupling using input from excited-state quantum chemical methods. Our results indicate that the electron transfer reaction coordinates between a triplet charge-transfer state and lower lying charge-separated and localized excitonic states are dominated by asymmetric and symmetric modes of the acetylene groups on either side of the central atom in this system. In particular, we find that while a nearly symmetric mode couples both the charge-separation and charge-recombination transitions more or less equally, the coupling along an asymmetric mode is far greater suggesting that IR excitation of the acetylene modes preferentially enhances charge-recombination transition relative to charge-separation.
Highlights
We report upon an analysis of the vibrational modes that couple and drive the state-to-state electronic transfer branching ratios in a model donor-bridge-acceptor system consisting of a phenothiazine-based donor linked to a naphthalene-monoimide acceptor via a platinumacetylide bridging unit
We focus our attention on the PTZ system and anticipate that the other systems in this study will exhibit similar behaviour due to the overall similarity of the various donor groups
We present here an analysis of the vibrational modes that couple to, and drive, the state-to-state electronic transitions, and largely determines their relative efficiencies of electron transfer in a model Donor-Bridge-Acceptor system, where the -CC-Pt-CC- unit acts as a bridge
Summary
We report upon an analysis of the vibrational modes that couple and drive the state-to-state electronic transfer branching ratios in a model donor-bridge-acceptor system consisting of a phenothiazine-based donor linked to a naphthalene-monoimide acceptor via a platinumacetylide bridging unit. One suggested means of controlling the outcome of an electron transfer process is to use an infra-red light to selectively excite specific nuclear motions that are strongly coupled to an electron transfer event[1,2,3,4] In this context, dynamics of photoinduced electron transfer have been investigated in a series of three donor-bridge-acceptor molecular triads[5,6,7]. IR excitation in the course of electron transfer has caused a 100% decrease in the CSS yield in 1, B50% effect in 2 and no effect in 3 This demonstration of control over excited-state dynamics strongly suggests that the acetylide stretching modes are significantly involved in the electron/nuclear coupling in these systems and play central roles in the electron transfer process. Our results indicate that the majority of the electronic coupling is mediated by local acetylide stretching modes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
