Photophysics of octabutoxy phthalocyaninato-Ni(II) in toluene: ultrafast experiments and DFT/TDDFT studies.
Reported herein is a combination of experimental and DFT/TDDFT theoretical investigations of the ground and excited states of 1,4,8,11,15,18,22,25-Octabutoxyphthalocyaninato-nickel(II), NiPc(BuO)(8), and the dynamics of its deactivation after excitation into the S(1)(pi,pi) state in toluene solution. According to X-ray crystallographic analysis NiPc(BuO)(8) has a highly saddled structure in the solid state. However, DFT studies suggest that in solution the complex is likely to flap from one D(2)(d)-saddled conformation to the opposite one through a D(4)(h)-planar structure. The spectral and kinetic changes for the complex in toluene are understood in terms of the 730 nm excitation light generating a primarily excited S(1) (pi,pi) state that transforms initially into a vibrationally hot (3)(d(z)2,d(x)2(-)(y)2) state. Cooling to the zeroth state is complete after ca. 8 ps. The cold (d,d) state converted to its daughter state, the (3)LMCT (pi,d(x)2(-)(y)2), which itself decays to the ground state with a lifetime of 640 ps. The proposed deactivation mechanism applies to the D(2)(d)-saddled and the D(4)(h)-planar structure as well. The results presented here for NiPc(BuO)(8) suggest that in nickel phthalocyanines the (1,3)LMCT (pi,d(x)2(-)(y)2) states may provide effective routes for radiationless deactivation of the (1,3)(pi,pi) states.
Gunaratne
Tissa C
TC
Center for Photochemical Sciences and Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, USA.
Gusev
Alexey V
AV
Peng
Xinzhan
X
Rosa
Angela
A
Ricciardi
Giampaolo
G
Baerends
Evert Jan
EJ
Rizzoli
Corrado
C
Kenney
Malcolm E
ME
Rodgers
Michael A J
MA
D003198:Computer Simulation; D018360:Crystallography, X-Ray; D008027:Light; D008665:Metalloporphyrins / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010777:Photochemistry; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry; D013997:Time Factors; D014050:Toluene / Q000737:chemistry*
C521012:1,4,8,11,15,18,22,25-octabutoxyphthalocyaninato-nickel(II); D008665:Metalloporphyrins; D009942:Organometallic Compounds; D012997:Solvents; D014050:Toluene