Laser control of double proton transfer in porphycenes: towards an ultrafast switch for photonic molecular wires

Abstract

Electronic excitation energy transfer along a molecular wire depends on the relative orientation of the electronic transition dipole moments of neighboring chromophores. In porphycenes this orientation is changed upon double proton transfer in the electronic ground state. We explore the possibility to trigger such a double proton transfer reaction by means of an infrared pump-dump laser control scheme. To this end a quantum chemical characterization of an asymmetrically substituted porphycene is performed using density functional theory. Ground state geometries, the topology of the potential energy surface for double proton transfer, and S 0 →S 1 transition energies are compared with the parent compound porphycene and a symmetric derivative. Employing a simple two-dimensional model for the double proton transfer, which incorporates sequential and concerted motions, quantum dynamics simulations of the laser driven dynamics are performed which demonstrate tautomerization control. Based on the orientation of the transition dipole moments this tautomerization may lead to an estimated change in the Förster transfer coupling of about 60%.

Tautomerization in 2,7,12,17‐Tetraphenylporphycene and 9‐Amino‐2,7,12,17‐tetraphenylporphycene: Influence of Asymmetry on the Direction of the Transition Moment

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Being of fundamental importance for understanding the multidimensional character of tautomerization coordinates, modeselectivity, tunneling, and the cooperativity between the motions of the two protons, such studies can also lead to applications of porphycenes, for example, as ultrafast switches or as information-storage media. [23,24] Our previous investigations of intramolecular double hydrogen transfer in porphycenes and porphyrins have resulted in the development of techniques for the determination of tautomerization rates. [25][26][27][28][29] These procedures are based on the use of polarized spectroscopy, both in steady-state and time-resolved regimes.…”

Vibrations and hydrogen bonding in porphycene

“…These findings point to the important role of tunneling and indicate a multidimensional character of tautomerization in porphycene, confirmed by theoretical studies. 18,24,27,[34][35][36] In a work devoted to identifying vibrational modes relevant for the proper description of the potential governing the motion of the inner protons, Ku¨hn and co-workers used four-dimensional and six-dimensional nuclear wavefunctions, the latter for a singly deuterated isotopologue. 35 Naturally, the key to understanding the complex mechanism of tautomerization in Pc is the knowledge of the intramolecular hydrogen bond (HB) parameters.…”

Ultrafast excited state dynamics and dispersion studies of nonlinear optical properties in dinaphthoporphycenes

“…25,26 Several other groups have also demonstrated their potential in applications such as two-photon imaging, PDT, 3D-optical memory, and ultrafast switches. [27][28][29] The true potential of any molecule is revealed only through extensive studies using different pulses (ns, ps, and fs pulses). Extending our earlier studies, 25,26 further we deliberated the NLO properties with ps pulses at 560 nm, 580 nm, and 600 nm.…”