Profiling energetics and spectroscopic signatures in prototropic tautomers of asymmetric phthalocyanine analogues.
Density functional theory (DFT) and time-dependent density functional theory (TDDFT) were used to explain discrepancies in UV-vis and MCD spectra of the metal-free tribenzo[b,g,l]thiopheno[3,4-q]porphyrazine (1), substituted tribenzo[b,g,l]porphyrazine (2), and 2,3-bis(methylcarboxyl)phthalocyanine (3). On the basis of gas-phase and polarized continuum solvation model (PCM) DFT and TDDFT calculations, it was suggested that both NH tautomers contribute to the spectroscopic signature of 1, whereas the Q-band region of 2 and 3 is dominated by a single NH tautomer. For all tested compounds, it was found that the combination of the BP86 exchange-correlation functional, 6-31G(d) basis set, and TDDFT-PCM approach provides the best accuracy in energies of the Q(x)- and Q(y)-bands of the individual NH tautomers as well as correctly describes their relative energy differences, which are important in understanding of experimental spectroscopy of the target systems.
Department of Chemistry and Biochemistry, 1039 University Drive, University of Minnesota, Duluth, Minnesota 55812, United States. vnemykin@d.umn.edu
Victor N
VN
Nemykin
Jared R
JR
Sabin
D005740:Gases; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D007700:Kinetics; D011166:Porphyrins / Q000737:chemistry*; D011789:Quantum Theory; D012997:Solvents; D013057:Spectrum Analysis; D013237:Stereoisomerism; D013816:Thermodynamics
D005740:Gases; D007211:Indoles; D054833:Isoindoles; D011166:Porphyrins; D012997:Solvents; C013647:phthalocyanine