A novel method for calculating rate constants for internal conversion (kIC) that simultaneously accounts for Duschinsky, anharmonic and Herzberg–Teller effects has been developed and implemented.

A fast method for estimating nonadiabatic coupling matrix elements (NACME) and rate constants for internal conversion (kIC) is presented. The method based on Plotnikov’s theory requires only calculations of the...

Cyclo[ n ]carbons ( n = 5, 7, 9, ..., 29) composed from an odd number of carbon atoms are studied computationally at density functional theory (DFT) and ab initio complete active space self-consistent field (CASSCF) levels of theory to get insight into their electronic structure and aromaticity. DFT calculations predict a strongly delocalized carbene structure of the cyclo[ n ]carbons and an aromatic character for all of them. In contrast, calculations at the CASSCF level yield geometrically bent and electronically localized carbene structures leading to an alternating double aromaticity of the odd-number cyclo[ n ]carbons. CASSCF calculations yield a singlet electronic ground state for the studied cyclo[ n ]carbons except for C 25 , whereas at the DFT level the energy difference between the lowest singlet and triplet states depends on the employed functional. The BHandHLYP functional predicts a triplet ground state of the larger odd-number cyclo[ n ]carbons starting from n = 13. Current-density calculations at the BHandHLYP level using the CASSCF-optimized molecular structures show that there is a through-space delocalization in the cyclo[ n ]carbons. The current density avoids the carbene carbon atom, leading to an alternating double aromaticity of the odd-number cyclo[ n ]carbons satisfying the antiaromatic [4k+1] and aromatic [4k+3] rules. C 11 , C 15 , and C 19 are aromatic and can be prioritized in future synthesis. We predict a bond-shift phenomenon for the triplet state of the cyclo[ n ]carbons leading to resonance structures that have different reactivity toward dimerization.

The binuclear half-lantern platinum(II) complexes [Pt-(pbt)(μ-S ∧ N)] 2 (pbtH = 2-phenylbenzothiazole, S ∧ N = benzo[d]thiazole-2-thiolate Pt1, 6-fluorobenzo[d]thiazole-2-thiolate Pt2, 6-chlorobenzo[d]thiazole-2-thiolate Pt3, 6-bromobenzo[d]thiazole-2-thiolate Pt4, and 6iodobenzo[d]thiazole-2-thiolate Pt5) were synthesized by the treatment of the in situ formed [Pt(pbt)(NCMe) 2 ]NO 3 complex and appropriate benzo[d]thiazole-2-thiole in the presence of t BuOK; yield: 51−84%. Complexes Pt1-5 exhibit intense red photoluminescence originated from 3MMLCT state reaching 22% room temperature quantum yields in a CH 2 Cl 2 solution. All complexes display excited-state decay kinetics both in solution and in the solid state; the kinetics was adequately modeled by single exponentials. The complexes display more than 10-fold higher electroluminescence brightness for the F-containing Pt2 (900 cd/m 2 ) and 2-fold higher electroluminescence brightness for the Cl-containing Pt3 (143 cd/m 2 ) compared to the H-substituted complex Pt1 (77 cd/m 2 ). It is argued that this impressive device luminance growth, occurred on formal replacement of H-to-F, is associated with the intermolecular strong hydrogen bonding H•••F relevant to the H-bond found in the structure of Pt2.

Spectral characteristics and luminescence under the photo-and electro-excitation of substituted dibenzthiophene sulfone and phenanthridine were studied in this paper. Diphenylamines are substituents introduced in the 2nd and 7th positions (linear con guration) or the 3rd and 6th positions (angular con guration) of dibenzthiophene sulfone or phenanthridine. All molecules show delayed uorescence, both in solutions and lms produced by thermal vacuum deposition. The value of the energy gap between the S 1 and T 1 states has been estimated and is shown to depend not only on the spatial arrangement of the fragments among themselves (linear or angular), but also on the nature of the substituent in diphenylamine. The highest electroluminescence brightness was found for the molecules, in which triplet levels are involved, both through the process of triplet-triplet annihilation and through thermally activated delayed uorescence.