ConspectusKohn–Sham theory (KST) is the "workhorse" of numerical quantum chemistry. This particularly true for first-principles calculations ground- and excited-state properties larger systems, including electronic spectra, dynamic static linear higher order response (including nonlinear optical (NLO) properties), conformational or averaging spectra properties, that are affected by coupling electron nuclear motion.This Account explores sometimes dramatic impact delocalization error (DE)...

Abstract Electronic circular dichroism and circularly polarized luminescence acid/base switching activity has been demonstrated in helicene‐bipyridine proligand 1 a its “rollover” cycloplatinated derivative 2 . Whereas displays strong bathochromic shift (>160 nm) of the nonpolarized upon protonation, complex slightly stronger emission. This strikingly different behavior between singlet emission organic helicene triplet organometallic rationalized by using quantum‐chemical calculations....

A fused π-helical N-heterocyclic carbene (NHC) system was prepared and examined through its diastereoisomerically pure cycloiridiated complexes. The latter display light-green phosphorescence with unusually long lifetimes circular polarization that depends on both the helical NHC P/M stereochemistry iridium Δ/Λ stereochemistry. These unprecedented features are attributed to extended π conjugation within carbenic ligand efficient helicene-NHC-Ir interaction.

In the framework of determining system-specific long-range corrected density functionals, question is addressed whether such tuned to satisfy condition -ε(HOMO) = IP or other energetic criteria, provide accurate electron densities. A nonempirical physically motivated two-dimensional tuning range-separated hybrid functionals proposed and applied particularly challenging case a molecular property that depends directly on ground-state density: copper electric field gradient (EFG) in CuCl. From...

Enantiopure mono-cycloplatinated-[8]helicene and bis-cycloplatinated-[6]helicene derivatives were prepared through column chromatography combined with crystallization of diastereomeric complexes using a chiral ancillary sulfoxide ligand. The UV-visible spectra, circular dichroism, molar rotations, (circularly polarized) luminescence activity these new helical have been examined in detail analysed the help first-principles quantum-chemical calculations.

Computations of natural optical activity (OA) from first principles (ab initio) have become indispensable in chiroptical studies molecular systems. Calculations are used to assign absolute configurations and analyze data, providing a basis for understanding their origin as well assigning predicting experimental results. In this article, methodology OA computations is outlined accompanied by review selected, mainly recent (ca. 2010–2016) achievements rotation, electronic vibrational circular...

Helicene-bis-diketopyrrolopyrrole derivatives display strong circular dichroism and red circularly polarized emission originating from exciton coupling chirality.

Introducing metal-vinyl ruthenium moieties onto [6]helicene results in a significant enhancement of the chiroptical properties due to strong metal-ligand electronic interactions. The electro-active Ru centers allow achievement first purely helicene-based redox-triggered switches. A combination electrochemical, spectroscopic, and theoretical techniques reveals that helicene moiety is noninnocent ligand bearing spin density.

Time-dependent density functional theory (TDDFT) computations are performed for 42 organic molecules and three transition metal complexes, with experimental molar optical rotations ranging from 2 to × 104 deg cm2 dmol–1. The performances of the global hybrid functionals B3LYP, PBE0, BHLYP, range-separated CAM-B3LYP LC-PBE0 (the latter being fully long-range corrected), investigated. performance different basis sets is studied. When compared liquid-phase data, do, on average, not perform...

For range-separated hybrid density functionals, the consequences of using system-specific range-separation parameters (γ) in calculations optical rotations (ORs) are investigated. Computed ORs at three wavelengths reported for methyloxirane, norbornenone, β-pinene, [6]helicene, [7]helicene, and two derivatives [6]helicene. The γ adjusted such that Kohn-Sham functional satisfy condition -ε(HOMO)(N) = IP. behavior energy as a function fractional total charge is also tested. test set molecules,...

Four members of a new class cycloborylated hexa-, octa-, and deca-helicenes (1 a-d) have been prepared in enantiopure form, along with two cycloplatinated d', 1 d1 ), further extending the family hexa- octa-helicenes reported previously. The azabora[n]helicenes display intense electronic circular dichroism large optical rotations; dependence activity on size helix (n=6, 8, 10) number boron atoms or 2) has examined detail both experimentally theoretically. photophysical properties...

π-Helical push-pull dyes were prepared and their (chir)optical properties investigated both experimentally computationally. Specific fluorescent behaviour of bis-substituted system was observed with unprecedented solvent effect on the intensity circularly polarized luminescence (CPL, dissymmetry factor decreasing from 10-2 to 10-3 an increase in polarity) that linked a change symmetry chiral excited state suppression interbranched exciton coupling. The results highlight potential CPL...

The incorporation of a rhenium atom within an extended helical π-conjugated bi-pyridine system impacts the chiroptical and photophysical properties resulting neutral or cationic complexes, leading to first examples rhenium-based phosphors that exhibit circularly polarized luminescence.

Chiral metal–organic frameworks have attracted interest for enantioselective separations and catalysis because of their high crystallinity pores with tunable shapes, sizes, chemical environments. the type M2(dobpdc) (M = Mg, Mn, Fe, Co, Ni, Zn; dobpdc4– 4,4′-dioxidobiphenyl-3,3′-dicarboxylate) seem particularly promising potential applications excellent stability, internal surface areas, strongly polarizing open metal coordination sites within channels, but to date these materials been...

A new type of chiroptical switch based on a bis-helicenic terpyridine, changing conformation upon Zn binding, has been designed.

The first enantiopure chiral-at-rhenium complexes of the form fac-ReX(CO)3 (:C^N) have been prepared, where :C^N is a helicene-N-heterocyclic carbene (NHC) ligand and X=Cl or I. These show strong changes in emission characteristics, notably strongly enhanced phosphorescence lifetimes (reaching 0.7 ms) increased circularly polarized (CPL) activity, as compared to their parent chiral models lacking helicene unit. halogen along with its position within dissymmetric stereochemical environment...

Abstract The combination of a bis‐alkynyl‐helicene moiety with two iron centers leads to novel electroactive species displaying unprecedented redox‐triggered chiroptical switching. Upon oxidation, strong changes vibrational modes (either local or extended coupled modes) are detected by circular dichroism and Raman optical activity. Remarkably, the sign rotation at 1.54 µm (that is, wavelengths typically used for telecommunications) upon oxidation while topology stereochemistry helicene...

A combination of multinuclear ultra-wideline solid-state NMR, powder X-ray diffraction (pXRD), absorption fine structure experiments, and first principles calculations platinum magnetic shielding tensors has been employed to reveal the previously unknown crystal Magnus' pink salt (MPS), [Pt(NH3)4][PtCl4], study isomeric green (MGS), examine their synthetic precursors K2PtCl4 Pt(NH3)4Cl2·H2O. simple synthesis MPS is detailed which produces relatively pure product in good yield. Broad (195)Pt,...

A novel enantiopure bis-helicenic 2,2′-bipyridine system was prepared using a Negishi coupling. Thanks to the bipyridine unit, coordination with ZnII and protonation processes were studied, revealing efficient tuning of photophysical (UV/visible emission) chiroptical properties (electronic circular dichroism circularly polarized system. The coordination/decoordination protonation/deprotonation appeared reversible, thus constituting switches.

Norbornenone, which has both a C═O and C═C chromophore in rigid bicyclic hydrocarbon framework, exhibits optical rotation (OR) an order of magnitude larger than that similar molecules with only one these chromophores (e.g., α-pinene). Its OR is also very sensitive to approximations electronic structure calculations. The present study demonstrates novel approach interpret using familiar concepts chemical bonding, aided by first-principles A theoretical procedure developed for analyzing the...

4-[5-(Naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol (NTBD) was extensively studied through stationary UV–vis absorption and fluorescence measurements in various solvents solvent mixtures by first-principles quantum chemical calculations. It observed that while polar (e.g., methanol) only a single emission band emerged; the analyzed 1,3,4-thiadiazole derivative capable of producing dual signals low polarity n-hexane) certain methanol/water). As clearly follows from...

The natural orbitals for chemical valence and the Ziegler−Rauk bond energy decomposition analysis were used to describe donor/acceptor character of N-heterocyclic carbenes (NHC)−metal in two groups square-planar rhodium(I) complexes: (NHC)RhCl(cod) (1-X; cod = 1,5-cyclooctadiene) (NHC)RhCl(CO)2 (2-X), with a group X H, Cl, NO2, or CN located on NHC ligand. results show that NHC−metal consists components originating from donation (σ symmetry) back-donation (two contributions π symmetry,...

Faraday rotation, the rotation of polarization light due to a magnetic field in direction propagation light, is used applications ranging from quantum memory detection biomagnetic fields. For these large necessary, but absorption detrimental. In search properties, we have characterized Verdet constant so far unexplored class mesogenic organic molecules. We report their spectra and provide an interpretation. A almost 2.5 × 105 deg T–1 m–1 found around 520 nm. This 3 orders magnitude larger...