Photoisomerization dynamics of spiropyran: A surface-hopping investigation

Abstract

In the present work, we performed a computational investigation of the photoisomerization of spiro[1,3-dihydroindole-2,2 ′ -chromene] [spiropyran (SP)] to merocyanine. The electronic energies and wavefunctions were obtained from configuration interaction calculations, using the floating occupation molecular orbital method, in a semiempirical framework. The parameters of the semiempirical Hamiltonian were re-optimized to reproduce ab initio literature data for SP. In our dynamics simulations, we considered, besides S 0 , the excited states S 1 , S 2 , and S 3 , which are very close in energy in the Franck-Condon region. We obtained a singlet lifetime of 0.67 ps, in line with the experimental results. We found the photoisomerization quantum yield to depend on the electronic state initially populated.

Spiropyran/Merocyanine Amphiphile in Various Solvents: A Joint Experimental–Theoretical Approach to Photophysical Properties and Self-Assembly

“…The chemical bond C –N is 1.472 Å; the experimental values are 1.438 [ 35 ], 1.452 [ 67 ] and from 1.426 to 1.446 Å [ 66 ]. The values reported in theoretical calculations published in the literature [ 49 , 53 , 54 , 56 , 57 ] are closer to the mentioned values evaluated in this work. For example, for MC ( Figure 3 b) the length of the double bond formed upon photoisomerization due to the ring opening is 1.385 Å, which coincides with the value reported by Murugan et al [ 56 ] in Car-Parrinello MD of MC and SP in water and by Sheng et al [ 49 ] for a set of compounds bearing various substituents and immersed in different solvents.…”

“…Theoretical studies published so far include quantum chemical description of the photoinduced ring-opening reaction of spiropyrans bearing various substituents [ 49 , 50 , 51 , 52 , 53 , 54 , 55 ], classical, semiclassical and ab initio calculations of the hydration mechanisms and the water shells around spiropyran and merocyanine, as well as MC protonated forms [ 49 , 56 , 57 , 58 , 59 ], and theoretical characterizations of the optical properties [ 60 ]. To the best of our knowledge, there are only a few papers devoted to the theory and modeling of the SP/MC amphiphiles.…”

Spiropyran/Merocyanine Amphiphile in Various Solvents: A Joint Experimental–Theoretical Approach to Photophysical Properties and Self-Assembly

“…The chemical bond C spiro -N is 1.472 Å; the experimental values are 1.438 [43], 1.452 [93] and from 1.426 to 1.446 Å [92]. The values reported in theoretical calculations published in literature [58,64,65,67,68] are closer to the mentioned values evaluated in this work. E.g., for MC (Figure 4b) the length of the double bond formed upon photoisomerization due to the ring opening is 1.385 Å, which coincides with the value reported by Murugan et al [67] in Car-Parrinello MD of MC and SP in water and by Sheng et al [58] for a set of compounds bearing various substituents and immersed in different solvents.…”

“…Theoretical studies published so far include quantum chemical description of the photoinduced ring-opening reaction of spiropyrans bearing various substituents [58][59][60][61][62][63][64][65][66], classical, semiclassical and ab initio calculations of the hydration mechanisms and the water shells around spiropyran and merocyanine, as well as MC protonated forms [58,[67][68][69][70], and theoretical characterizations of the optical properties [71]. To the best of our knowledge, there is only a few papers devoted to the theory and modeling of the SP/MC amphiphiles.…”

TD‐DFT study of BIPS spiropyran: Effects of functionals and high‐polarity solvent on CspiroO bond dissociation and recovery

“…The dynamics of SPt was also studied in a recent paper. 27 Its important result was the very close mutual arrangement of the PESs of the S 1 , S 2 , and S 3 excited states in the Franck-Condon region.…”