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.

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...

The stability over time (repeatability) for the determination of site-specific 13C/12C ratios at natural abundance by quantitative 13C NMR spectroscopy has been tested on three probes: enriched bilabeled [1,2-13C2]ethanol; ethanol abundance; and vanillin abundance. It is shown in all cases that standard deviation a series measurements taken every 2-3 months periods between 9 13 equal to or smaller than calculated from 5-10 replicate made single sample. precision which can be achieved using...

Abstract 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.

A novel organometallic gel whose molecular building block contains either one (Ru1) or two Ru (Ru2) atoms is presented and for the latter molecule, its supramolecular properties in solution investigated....

Abstract Strontium and calcium (alkaline earth: Ae) olefin complexes stabilised by secondary Ae⋅⋅⋅F−C β‐agostic Ae⋅⋅⋅H−Si interactions are presented. Olefin coordination onto the alkaline earths is plain in solid state, it thermodynamically favoured over of THF. The existence Ae⋅⋅⋅olefin corroborated solution NMR data DFT computations. mode varies with steric effects and, if enforced, dissociation can be compensated other non‐covalent interactions, as supported

Ag–N-heterocyclic carbene (NHC) complexes can occur as neutral [(NHC)AgX] and/or ionic [(NHC)2Ag][AgX2] species in solution. Herein, the behavior of four bearing common bulky N,N′-diaryl NHCs was examined DMSO. 1H NMR experiments performed systematically CDCl3 and DMSO-d6 were used to detect DMSO or chloride ion induced equilibration between forms at very different time scales. We observed that solubilization IMesAgCl SIMesAgCl 300 K led less than a few minutes complete equilibration. Here,...

Regiodivergent C–H bond arylation of fluorinated 2-arylpyridines and 2-arylquinolines has been developed. The use Pd catalyst allows functionalization the aryl flanked by two fluorine atoms (most acidic position), while using Ru catalyst, takes place on unit at ortho position heterocycle. Both reaction conditions exhibit a good functional group tolerance. synthetically useful selectivity observed with was applied to design C^N ligands for preparation luminescent cationic iridium(III)...

The first helicene–NHC–Ir complexes have been prepared in enantiopure forms and analyzed detail.

Abstract A new enantiopure cyclometallated iridium complex bearing a [4]helicenic ‐coordinating and two dfppy (2‐(2,4‐difluorophenyl)‐pyridyl) ligands was prepared. This displayed long‐lived phosphorescence both in solution the solid state. Its chiroptical properties, namely electronic circular dichroism circularly polarized luminescence, were also examined. Comparison with former chiral complexes enabled assignment of Δ Ir ‐(−) Λ ‐(+) absolute configurations.

Abstract Mono‐ and di‐boranil‐substituted helicenes were prepared by BF 2 ‐borylation of the corresponding anils, readily synthesized condensation 2‐amino‐ 2,15‐diamino‐helicenes with 4‐(diethylamino)salicylaldehyde. After enantiomeric resolution using HPLC, their chiroptical properties including circularly polarized fluorescence in solution PMMA films investigated rationalized help NMR, X‐ray quantum‐chemical calculations.

We report the straightforward one-pot synthesis of novel 5- or 6-membered P-heterocycles featuring an internal ylidic bond: P-containing acenaphthylenes and phenanthrenes. The stability compounds tolerates post-functionalization through direct arylation to introduce electron-rich/poor substituents synthetic strategy is also compatible with preparation more elaborate polyaromatic scaffolds such as acenes helicenes. Using a joint experimental (X-ray analysis, optical redox properties)...

The recent development of 13C NMR to measure absolute 13C/12C ratios at natural abundance has made it possible examine site-by-site variation abundance. This technique been applied two common physical processes: distillation and column chromatography. It is shown that the target molecules, ethanol vanillin, respectively, both show isotopic fractionation differs in size and/or sense each carbon atom. observation this disparity behavior novel unexpected. SNIF-NMR appears as a new effective...

N-Aryl-N-methyl-2-tert-butyl-6-methylaniline derivatives exhibit a rotationally stable N-C axially chiral structure and the rotational barriers around an axis increased with increase in electron-withdrawing character of para-substituent on aryl group. X-ray crystal structural analysis DFT calculation suggested that considerable change by electron effect para-substituents is due to disappearance resonance stabilization energy caused twisting para-substituted phenyl group transition state....

We report the straightforward synthesis of unprecedented electron-acceptors based on dicationic P-containing PAHs (Polycyclic Aromatic Hydrocarbons) copper mediated radical approach. In these systems, two phosphoniums are connected through various backbones. The impact π-extension both optical and redox properties is investigated using a joint experimental (UV/Vis absorption, fluorescence cyclic voltammetry) theoretical approach (TD-DFT calculations). Finally, (spectro)-electrochemical...

The synthesis and photophysical chiroptical properties of novel aza[n]helicenes (6a–d, 10a,b, n = 4–7) substituted with one or two 2-pyridyl groups are described. preparation was performed via an adapted Mallory reaction using aromatic imines as precursors. obtained class helical 2,2′-bipyridine ligands then coordinated to Ru(bipy)22+ units, thus affording the first diastereomerically enantiomerically pure [RuL(bipy)2]2+ (11a,c, L 6a,c) [Ru2L′(bipy)4]4+ (12, L′ 10b) complexes. topology...

π ligands such as olefins and alkynes bind intramolecularly to the metal atom in d0 complexes of large alkaline earths (Ae) calcium strontium supported by fluoroalkoxo with dangling unsaturated C═C or C≡C bonds, having amide N(SiMe2H)2– coligand. These O-bridged dinuclear are further stabilized secondary C–F→Ae β-Si–H···Ae interactions. In a set structurally related Ca-olefin complexes, strength these interactions gradually increases coordination olefin onto Ca2+ becomes weaker (from...

Abstract 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...

The photophysical and chiroptical properties of a novel, chiral helicene-NHC-Re(I) complex bearing an N-(aza[6]helicenyl)-benzimidazolylidene ligand are described, showing its ability to emit yellow circularly polarized luminescence. A comparative analysis this new system with other helicene-Re(I) complexes reported date illustrates the impact structural modifications on emissive absorptive properties.

Triskelion-shaped cycloiridiated complexes with three <italic>N</italic>-[6]helicenyl-NHC ligands were prepared uncommon diastereoselectivities and their configurations assigned using NMR analyses. They show strong ECD OR, yellow CP phosphorescence.

Stereospecific synthesis and (chir)optical redox properties of helicenoid-based phosphepine as well chiral P-containing polycyclic aromatic hydrocarbons are presented.

Abstract The Kinugasa reaction, applied to propargylic gem ‐difluorides, allows a very direct and efficient synthesis of new exoalkylidene β‐lactams with fluorine in the vinylic position.

Investigations based on NMR spectroscopy, mass spectrometry, and DFT calculations shed light the metallic species generated in rhodium-catalyzed asymmetric [2+2+2] cycloaddition reaction between diynes isocyanates with chiral phosphate TRIP. The catalytic mixture comprising [{Rh(cod)Cl}2 ], 1,4-diphenylphosphinobutane (dppb), Ag(S)-TRIP actually gives rise to two species, both having an effect stereoselectivity. One is a rhodium(I) complex which TRIP weakly coordinating counterion, whereas...

A new synthetic route toward the synthesis of benzo[b]phospholes- and benzo[b]siloles-fused pyrenes using a transition metal-catalyzed C–H bond activation is described. The compounds were fully characterized including X-ray diffraction. combined experimental theoretical study shows that both heteroatom substitution pattern impact optical redox properties.