0000000000082628
AUTHOR
Hans ÅGren
Polymorph acceptor-based triads with photoinduced TADF for UV sensing
Abstract In contrast to many donor–acceptor type organic luminophores exhibiting thermally activated delayed fluorescence (TADF), two deep blue TADF emitters designed in this work contain only typical electron accepting moieties with different electron accepting abilities. Derivatives of benzophenone and diphenylsulfone substituted with phenothiazine-5,5-dioxide donor moieties were synthesized and studied. In addition to the TADF, green to blue emission color switching and strong fluorescence intensity enhancement by more than 60 times was detected for THF solution of the derivative of phenothiazine-5,5-dioxide and benzophenone under increase of UV excitation dose. We proved by a variety of…
Ab initio calculations of zero-field splitting parameters in linear polyacenes
Abstract The results of ab initio calculations of zero-field splitting (ZFS) parameters are presented for the linear polyacenes from benzene to pentacene. We show how the electron spin–spin (SS) parameters can be efficiently obtained from restricted high-spin open-shell wave functions (ROHF), and present calculations of these, comparing with the results of a recent multi-configurational self-consistent field approach. The SS parameters are obtained from electron SS coupling strengths evaluated as expectation values over the wave functions and from state-to-state spin–orbit (SO) interactions. The results for the two lowest triplet states of naphthalene demonstrate that excellent values can b…
A comparison of density-functional-theory and coupled-cluster frequency-dependent polarizabilities and hyperpolarizabilities
The frequency-dependent polarizabilities and hyperpolarizabilities of HF, CO, H2O and para-nitroaniline calculated by density-functional theory are compared with accurate coupled-cluster results. Whereas the local-density approximation and the generalized gradient approximation (BLYP) perform very similarly and overestimate polarizabilities and, in particular, the hyperpolarizabilities, hybrid density-functional theory (B3LYP) performs better and produces results similar to those obtained by coupled-cluster singles-and-doubles theory. Comparisons are also made for singlet excitation energies, calculated using linear response theory.
Two-photon absorption of BF2-carrying compounds: insights from theory and experiment
This communication presents a structure–property study of a few novel pyridine-based difluoroborate compounds with a N–BF2–O core, which exhibit outstanding fluorescence properties. To exploit their potential for two-photon bioimaging, relationships between the two-photon action cross section and systematic structural modifications have been investigated and unravelled.
The Dalton quantum chemistry program system
Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, MOller-Plesset, confi ...
A coupled-cluster study of lanthanum trihalide structures
Coupled-cluster calculations were carried at the CCSD(T)-level in order to determine the structures and vibrational spectra of the lanthanum trihalides LaF3 and LaCl3. Two different approaches were employed to describe scalar relativistic effects; the quasi-relativistic Effective Core Potential approach and the all-electron Douglas–Kroll approach. We find LaF3 to be of pyramidal structure and LaCl3 to be planar. The obtained vibrational frequencies accord well with experimental measurements except for the ν2 mode. This disagreement is attributed to the intrinsic uncertainty of harmonic frequencies of this fluxional mode as extracted from spectra which were obtained at high temperature and f…
Flexible diphenylsulfone versus rigid dibenzothiophene-dioxide as acceptor moieties in donor-acceptor-donor TADF emitters for highly efficient OLEDs
DG acknowledges funding from the ERDF PostDoc project No. 1.1.1.2/VIAA/1/16/177 . This research is/was funded by the European Regional Development Fund according to the supported activity ‘ Research Projects Implemented by World-class Researcher Groups ’ under Measure No. 01.2.2-LMT-K-718 . Ministry of Science and Technology (MOST), Taiwan , Grant No. MOST 106-2923-E-155-002-MY3 . This work was also supported by the Ministry of Education and Science of Ukraine (projects no. 0117U003908 and 0118U003862 ), and by the Olle Engkvist Byggmästare foundation (contract No. 189-0223 ). The quantum-chemical calculations were performed with computational resources provided by the High Performance Comp…
Substituent effects on the photophysical properties of fluorescent 2-benzoylmethylenequinoline difluoroboranes: A combined experimental and quantum chemical study
Abstract In this study, we demonstrate a successful synergy between theory and experiment and report on the photophysical properties of a recently synthesized series of substituted 2-benzoylmethylenequinoline difluoroboranes with a view towards the effect of substitution on their properties. In general difluoroboranes are known to have a bright fluorescence but for some analogs the properties are not fully understood. Quantum chemistry methods have been applied in order to explain a complex structure of the absorption and emission spectra and to gain an insight into the charge redistribution upon the excitation of the investigated molecules. We demonstrate that the spectra of this important…
CCDC 1520868: Experimental Crystal Structure Determination
Related Article: Joanna Bednarska, Robert Zaleśny, Małgorzata Wielgus, Beata Jędrzejewska, Rakesh Puttreddy, Kari Rissanen, Wojciech Bartkowiak, Hans Ågren, Borys Ośmiałowski|2017|Phys.Chem.Chem.Phys.(PCCP)|19|5705|doi:10.1039/C7CP00063D
CCDC 1520867: Experimental Crystal Structure Determination
Related Article: Joanna Bednarska, Robert Zaleśny, Małgorzata Wielgus, Beata Jędrzejewska, Rakesh Puttreddy, Kari Rissanen, Wojciech Bartkowiak, Hans Ågren, Borys Ośmiałowski|2017|Phys.Chem.Chem.Phys.(PCCP)|19|5705|doi:10.1039/C7CP00063D