DFT study of vibronic properties of d8 (Ni-, Pd-, and Pt-) phthalocyanines

Abstract

By means of density functional theory, we have studied the electronic structure and vibronic properties of single neutral NiPc, PdPc, and PtPc molecules and their singly and doubly ionized cations and anions. In particular, the vibronic couplings and reorganization energies of all systems are compared. Partitioning of the reorganization energy, corresponding to the photoelectron spectra of the first and second ionizations of studied molecules, into normal mode contributions shows that the major contributions are due to several vibrational modes with a(1g) symmetry and energies lower than 1600 cm(-1). The results reveal that the reorganization energy due to the singly positive ionization in the studied molecules is up to about one order of magnitude less than other reorganization energies. This makes these metal phthalocyanines, from the perspective of intramolecular reorganization energies, attractive as electron donor for intramolecular electron transfer in electron acceptor-donor systems.

Intramolecular reorganization energy in zinc phthalocyanine and its fluorinated derivatives: a joint experimental and theoretical study

“…Theoretical calculations have shown that comparable small reorganization energies are characteristic as well for other metal phthalocyanines. 13,14,16,32 For instance, values in the range of 36-39 meV at a comparable level of calculations were estimated recently for holes in TiO-, 13 Ni-, Pd-and PtPc. 16 Interestingly, the 6-31G(d,p)/B3LYP estimate of reorganization energy of the metal free H 2 Pc is somewhat larger, 45 meV.…”

“…11 Therefore, the investigation of the electronic and electron-vibrational interactions in metal phthalocyanines, that ultimately define the material performance, also gained significant attention. [12][13][14][15][16][17][18] In this communication, we report the electron-vibration couplings in ZnPc on the basis of a joint experimental and theoretical study. We have carried out highresolution gas-phase ultraviolet photoelectron spectroscopy (UPS) measurements and performed density functional theory calculations.…”

Ultrafast Charge Transfer in Nickel Phthalocyanine Probed by Femtosecond Raman-Induced Kerr Effect Spectroscopy

“…62–66,71–78 The NiPc-(OBu) 8 RR spectrum between 1100 and 1600 cm −1 (Figure 3, bottom) is dominated by phthalocyanine ring vibrations. The bands between 1390 and 1480 cm −1 are due to isoindole ring stretching, while the most intense band, at 1551 cm −1 , is assigned to C α –N b –C α bridge bond stretching.…”

“…62–66,71–78 These bonds are responsive to changes in macrocycle geometry and in the occupancy of the macrocycle π orbitals. In particular, expansion of the macrocycle core, as a result of increasing the central metal radius, produces characteristic downshifts in the macrocycle ring modes.…”

“…The characteristic band frequencies and polarizations of the ground-state NiPc(OBu) 8 FRIKES spectrum afford reliable assignments to modes of the Pc macrocycle, involving stretching of the ring C–N and C–C bonds. 62 − 66 , 71 − 78 These bonds are responsive to changes in macrocycle geometry and in the occupancy of the macrocycle π orbitals. In particular, expansion of the macrocycle core, as a result of increasing the central metal radius, produces characteristic downshifts in the macrocycle ring modes.…”