Software for the frontiers of quantum chemistry: An overview of developments in the Q-Chem 5 package

The Journal of Chemical Physics, Journal Year: 2021, Volume and Issue: 155(8)

Published: Aug. 23, 2021

This article summarizes technical advances contained in the fifth major release of Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library exchange-correlation functionals, along with a suite correlated many-body methods, continues to be hallmark software. The methods include novel variants both coupled-cluster and configuration-interaction approaches based on algebraic diagrammatic construction variational reduced density-matrix methods. Methods highlighted 5 tools for modeling core-level spectroscopy, describing metastable resonances, computing vibronic spectra, nuclear-electronic orbital method, several different energy decomposition analysis techniques. High-performance capabilities including multithreaded parallelism support calculations graphics processing units are described. boasts community well over 100 active academic developers, continuing evolution software is supported by an "open teamware" model increasingly modular design.

Language: Английский

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Charge-Transfer Excitations within Density Functional Theory: How Accurate Are the Most Recommended Approaches?

Journal of Chemical Theory and Computation, Journal Year: 2022, Volume and Issue: 18(3), P. 1646 - 1662

Published: Feb. 24, 2022

The performance of the most recent density functionals is assessed for charge-transfer (CT) excitations using comprehensive intra- and intermolecular CT benchmark sets with high-quality reference values. For this comparison, state-of-the-art range-separated (RS) long-range-corrected (LC) double hybrid (DH) approaches are selected, global DH LC also inspected. correct long-range behavior exchange–correlation (XC) energy extensively studied, various descriptors compared as well. Our results show that robust attained by RS-PBE-P86/SOS-ADC(2), it suitable to describe both types outstanding accuracy. Furthermore, concerning intramolecular transitions, unexpectedly excellent obtained DHs, but their limitations demonstrated bimolecular complexes. Despite LC-DH methods common excitations, serious deficiencies pointed out wrong XC revealed. application hybrids such transitions not recommended in any respect.

Language: Английский

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Room-Temperature Phosphorescence from Pd(II) and Pt(II) Complexes as Supramolecular Luminophores: The Role of Self-Assembly, Metal–Metal Interactions, Spin–Orbit Coupling, and Ligand-Field Splitting

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(7), P. 3937 - 3951

Published: Feb. 13, 2023

The synthesis as well the structural and photophysical characterization of two isoleptic bis-cyclometalated Pt(II) Pd(II) complexes, namely [PtL] [PdL], bearing a tailored dianionic tetradentate ligand (L2–) are reported. isostructural character intermolecular interactions [PdL] were assessed by NMR spectroscopy X-ray diffraction analysis. Both complexes show fully ligand-controlled aggregation, demonstrating that judicious molecular design can tune properties. In fact, introduction fluorine atoms on defined positions methoxy groups complementary sites, metal–metal be forced head-to-tail stacking. Hence, shows luminescence from metal-perturbed ligand-centered or metal-metal-to-ligand charge-transfer triplet states in diluted solutions, frozen glasses crystals, with high photoluminescence quantum yields long lifetimes microsecond range. At room temperature (RT) concentrated fluid palladium analogue surprisingly emits aggregated species involving supramolecular interactions. Time-resolved transient absorption spectroscopies demonstrated ultrafast intersystem crossing occurs for both metals, which outruns any competitive relaxation pathway photoexcited singlet state. Furthermore, we demonstrate radiationless deactivation suppressed glassy matrices at 77 K solutions RT. cases indicated density functional theory calculations, lowest emissive state acts an energy trap thermal population dissociative formal occupation antibonding Pd-centered 4dx2–y2 orbital is suppressed. This gap between dark surpasses kT.

Language: Английский

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Effects of solvent polarity on the novel excited-state intramolecular thiol proton transfer and photophysical property compared with the oxygen proton transfer

Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, Journal Year: 2023, Volume and Issue: 293, P. 122475 - 122475

Published: Feb. 9, 2023

Language: Английский

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Janus-type emission from a cyclometalated iron(iii) complex

Nature Chemistry, Journal Year: 2023, Volume and Issue: 15(4), P. 468 - 474

Published: Feb. 27, 2023

Although iron is a dream candidate to substitute noble metals in photoactive complexes, realization of emissive and compounds demanding due the fast deactivation their charge-transfer states. Emissive are scarce dual emission has not been observed before. Here we report FeIII complex [Fe(ImP)2][PF6] (HImP = 1,1'-(1,3-phenylene)bis(3-methyl-1-imidazol-2-ylidene)), showing Janus-type from ligand-to-metal charge transfer (LMCT)- metal-to-ligand (MLCT)-dominated This behaviour achieved by ligand design that combines four N-heterocyclic carbenes with two cyclometalating aryl units. The low-lying π* levels units lead energetically accessible MLCT states cannot evolve into LMCT With lifetime 4.6 ns, strongly reducing oxidizing MLCT-dominated state can initiate electron reactions, which could constitute basis for future applications photoredox catalysis.

Language: Английский

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Control over Charge Separation by Imine Structural Isomerization in Covalent Organic Frameworks with Implications on CO₂ Photoreduction

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(7), P. 4489 - 4499

Published: Feb. 8, 2024

Two-dimensional covalent organic frameworks (COFs) are an emerging class of photocatalytic materials for solar energy conversion. In this work, we report a pair structurally isomeric COFs with reversed imine bond directions, which leads to drastic differences in their physical properties, photophysical behaviors, and CO2 reduction performance after incorporating Re(bpy)(CO)3Cl molecular catalyst through bipyridyl units on the COF backbone (Re-COF). Using combination ultrafast spectroscopy theory, attributed these polarized nature that imparts preferential direction intramolecular charge transfer (ICT) upon photoexcitation, where unit acts as electron acceptor forward case (f-COF) donor reverse (r-COF). These interactions ultimately lead Re-f-COF isomer function efficient photocatalyst, while Re-r-COF shows minimal activity. findings not only reveal essential role linker chemistry plays properties but also offer unique opportunity design photosensitizers can selectively direct charges.

Language: Английский

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Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs

Nature Materials, Journal Year: 2024, Volume and Issue: 23(4), P. 519 - 526

Published: March 13, 2024

Abstract Hyperfluorescence shows great promise for the next generation of commercially feasible blue organic light-emitting diodes, which eliminating Dexter transfer to terminal emitter triplet states is key efficiency and stability. Current devices rely on high-gap matrices prevent transfer, unfortunately leads overly complex from a fabrication standpoint. Here we introduce molecular design where ultranarrowband emitters are covalently encapsulated by insulating alkylene straps. Organic diodes with simple emissive layers consisting pristine thermally activated delayed fluorescence hosts doped exhibit negligible external quantum drops compared non-doped devices, enabling maximum 21.5%. To explain high in absence matrices, turn transient absorption spectroscopy. It directly observed that sensitizer host can be substantially reduced an emitter, opening door highly efficient ‘matrix-free’ hyperfluorescence.

Language: Английский

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Oxidative two-state photoreactivity of a manganese(IV) complex using near-infrared light

Nature Chemistry, Journal Year: 2024, Volume and Issue: 16(5), P. 827 - 834

Published: Feb. 8, 2024

Language: Английский

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Reference Energies for Intramolecular Charge-Transfer Excitations

Journal of Chemical Theory and Computation, Journal Year: 2021, Volume and Issue: 17(6), P. 3666 - 3686

Published: May 6, 2021

In the aim of completing our previous efforts devoted to local and Rydberg transitions in organic compounds, we provide a series highly-accurate vertical transition energies for intramolecular charge-transfer occurring ($\pi$-conjugated) molecular compounds. To this end apply composite protocol consisting linear-response CCSDT excitation determined with Dunning's double-$\zeta$ basis set corrected by CC3/CCSDT-3 obtained corresponding triple-$\zeta$ basis. Further corrections (up \emph{aug}-cc-pVQZ) are at CCSD CC2 level. We report 30 17 These reference values then used benchmark wave function (CIS(D), SOPPA, RPA(D), EOM-MP2, CC2, CCSD, CCSD(T)(a)*, CCSDR(3), CCSDT-3, CC3, ADC(2), ADC(3), ADC(2.5)), Green's function-based Bethe-Salpeter equation (BSE) formalism performed on top partially self-consistent ev$GW$ scheme considering two different starting points (BSE/ev$GW$@HF BSE/ev$GW$@PBE0), TD-DFT combined several exchange-correlation functionals (B3LYP, PBE0, M06-2X, CAM-B3LYP, LC-$\omega$HPBE, $\omega$B97X, $\omega$B97X-D, M11).

Language: Английский

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Conjugation- and Aggregation-Directed Design of Covalent Organic Frameworks as White-Light-Emitting Diodes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(2), P. 1061 - 1068

Published: Jan. 4, 2021

2D covalent organic frameworks (COFs) have emerged as a promising class of luminescent materials due to their structural diversity, which allows the systematic tuning building blocks optimize emitting properties. However, significant knowledge gap exists between design strategy and fundamental understanding key parameters that determine photophysical In this work, we report two highly emissive sp2-C-COFs direct correlation structure (conjugation aggregation) with light absorption/emission, charge transfer (CT), exciton dynamics, properties function materials. We show white can be obtained by simply coating COFs on an LED strip or mixing COFs. Using combination time-resolved absorption emission spectroscopy well computational prediction, planarity, conjugation, orientation dipole moment, interlayer aggregation not only light-harvesting ability but also control relaxation pathway photoluminescent quantum yield.

Language: Английский

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