Coherence Length Determination of meso−meso Linked Porphyrin Arrays Based on Forward−Backward Pair Trajectory Analysis

Abstract

We investigated the excitation energy transfer process of meso-meso linked zinc(II) porphyrin arrays using the on-the-fly filtered propagator path integral method. Details of the dynamics such as coherence length of a porphyrin array are estimated by analysis of the characteristics of forward-backward pair trajectories. Upon examination of the convergence of the reduced density matrix with respect to the subset of Hilbert space trajectories, we determine the number of porphyrin units that form collective coherent states, that is, the coherence length. Simulation results show that the coherence length of zinc(II) porphyrin arrays is up to 4 units, which agrees excellently with experimental observations. On the other hand, the energy bias provided by the energy-accepting 5,15-bisphenylethynylated zinc(II) porphyrin reduces the degree of coherence which becomes negligible for an array with more than for porphyrin units. Considering conformational inhomogeneity, we found that the experimentally determined coherence length is the result of electronic and environmental influence rather than the structure disorder. Temperature dependence is also discussed.

Pathway Analysis on DNA Charge Transfer through Adenine and Guanine Bridges

“…Contribution of off-diagonal pair trajectories depends on coherence between constituting sites: off-diagonal trajectories consisting of incoherent sites have no contribution to the dynamics and are filtered during the on-the-fly filtering algorithm. Therefore, the deviation between forward and backward segments, Δ FB , of sorted pair trajectories can be used as a measure of the DOC. , Consider a system where two coherent sites | i ⟩ and | j ⟩ are within χ sites apart. Two sites satisfying | j − i | > χ are incoherent then all the significantly contributing trajectories should satisfy the condition Δ FB ≤ χ at any time.…”

Review of porphyrin-based photodynamic therapy materials

“…On the basis of chemical coupling reactions and self-assembly, hydrophilic or amphiphilic molecules including peptides, saccharide, lipids and surfactants can be coupled with porphyrins. These adopted strategies as well as introduced functionalities produce functionalized porphyrinic amphiphiles with improved watersolubility and retained intrinsic properties of porphyrin [43][44][45]. Additionally, the amphiphilic porphyrinic photosensitizers can further self-assemble into nano-sized particles to passively accumulate at tumor sites via enhanced permeability and retention (EPR) effect.…”

Review of Conjugated Porphyrin Systems

“…224 Fig. 23 Pictorial representation of electron transfer in a porphyrin-CNT hybrid photovoltaic cell. 217…”

“…21 Porphyrins generally are attractive from an electrochemical perspective and their redox properties can be tuned by varying the substituents on the meso/β positions, metallation and core-modification. 22 Porphyrins/metalloporphyrins and their derivatives have been used as excellent photosensitizers in dye-sensitized solar cell (DSSC) applications 23 and photodynamic therapy (PDT); 24 as catalysts for chemical transformations including asymmetric synthesis; 25 in supramolecular chemistry 26 and organic electronics, 27,28 etc.…”