Tweaking the Charge Transfer: Bonding Analysis of Bismuth(III) Complexes with a Flexidentate Phosphane Ligand

To account for the charge transfer and covalent character in bonding between P and Bi centers, the electronic structures of [P(C6H4-o-CH2SCH3)3BiCln](3–n)+ (n = 0–3) model species have been investigated computationally. On the basis of this survey a synthetic target compound with a dative P→Bi bond has been selected. Consecutively, the highly reactive bismuth cage [P(C6H4-o-CH2SCH3)3Bi]3+ has been accessed experimentally and characterized. Importantly, our experiments (single-crystal X-ray diffraction and solid-state NMR spectroscopy) and computations (NBO and AIM analysis) reveal that the P···Bi bonding in this trication can be described as a dative bond. Here we have shown that our accordion-like molecular framework allows for tuning of the interaction between P and Bi centers

Topologically diverse polycyclic aromatic hydrocarbons from pericyclic reactions with polyaromatic phospholes

International audiencePolycyclic Aromatic Hydrocarbons (PAHs) with planar, twisted and negatively curved topologies were obtained from polycyclic phospholes using pericyclic reactions. Deviation from planarity is due to steric interaction between the PAH core and the ester substituents. These structural effects on the optical and redox properties were studied and rationalized through DFT calculations. This synthetic approach thus allows the preparation of topologically diverse PAHs allowing finetuning their electronic properties, with potential applications in organic electronics

Stereospecific synthesis of chiral P-containing polyaromatics based on 7-membered P-rings

International audienceWe present the stereospecific synthesis of helicenoid-based phosphepines (7-membered P-rings) as well as chiral P-containing polycyclic aromatic hydrocarbons. In these systems, an axial to central chirality transfer takes place from the BINAP moiety to the P-atom. The impact of the molecular design on the structure, the (chir)optical (including circularly polarized luminescence) and redox properties are investigated

Étude de systèmes pi-conjugués contenant des hétéroéléments

Les hydrocarbures aromatiques polycycliques (HAP) et autres nanostructures carbonées peuvent offrir un large éventail d'applications et ces composés sont accessibles par diverses méthodes de chimie organique. De nos jours, l'importance des composés aux propriétés spécifiques ne cesse d'augmenter. Dans le premier chapitre, j'ai poursuivi un travail préliminaire sur la synthèse de PAHs à topologies variées. En plus de la synthèse des HAPs distordus, j'ai également effectué l'optimisation des procédures de synthèse et la post-fonctionnalisation des nouveaux HAPs. Un nouveau phosphole polycyclique plan a été synthétisé et utilisé dans la réaction de cycloaddition pour obtenir un HAP plan. Une étude mécanistique a été effectuée de manière expérimentale et théorique. En plus du travail de synthèse, les propriétés électroniques, optiques et structurelles ainsi que l'aromaticité de ces composés ont également été étudiées. Dans un second chapitre, j'ai prouvé que la synthèse de phosphépines polyaromatiques à partir de BINAP(O)2 est stéréospécifique. La stabilité conformationnelle des énantiomères a également été étudiée avec des méthodes théoriques et expérimentales. La complexation avec de l'or et les propriétés chiroptiques de ces composés ont également été étudiées. Dans un troisième chapitre lié l'étude structurelle d’oxydes de bromonaphtyl phosphines, des méthodes de calcul ont été appliquées pour comprendre la stabilité chimique particulière de ces composés ainsi que leur comportement en RMN (signaux élargis). Ce comportement a été attribué à une combinaison de protection stérique et de liaisons pnictogènes faibles. Enfin, en utilisant une voie de synthèse modifiée, de nouveaux siloles à substitution phosphanyle ont été préparés et caractérisés expérimentalement. Pour comprendre les différentes propriétés spectroscopiques de ces composés, des calculs TD-DFT ont été effectués.Polycyclic aromatic hydrocarbons (PAHs) and other carbon nanostructures can offer a wide range of applications and these compounds can be prepared by various methods of organic chemistry. Nowadays, the importance of compounds with special properties continues to increase. In the first chapter, I continued a preliminary work on novel access to topologically diverse PAHs. In addition to the synthesis of contorted PAHs, I also performed the optimization of synthetic procedures, and the postfunctionalization of the new PAHs. A new planar polycyclic phosphole was synthesized and it was used as starting material in cycloaddition reaction to obtain a planar PAH. A mechanistic study was performed both theoretically and experimentally. Besides the synthetic work, the electronic, optical and structural properties as well as the aromaticity of these compounds were also investigated. In a second chapter, I proved that the synthesis of polyaromatic phosphepines from BINAP(O)2 is stereospecific, and the conformational stability of the enantiomers was also investigated with computational and experimental methods. The complexation with gold and the chiroptical properties of these compounds were also investigated. In a third chapter, during the structural study of bromonaphthyl phosphine oxides, computational methods were applied to understand the special chemical stability of these compounds and the peculiar NMR behavior (broad resonances). Such behavior was attributed to a combination of steric shielding and weak pnictogen interactions. Finally, with a modified synthetic route new phosphanyl substituted siloles were synthesized and characterized experimentally. To understand the spectroscopic difference of these compounds TD-DFT calculations were performed

Weak pnictogen bond with bismuth: Experimental evidence based on Bi-P through-space coupling

To study pnictogen bonding involving bismuth, flexible accordion‐like molecular complexes of the composition [P(C6H4‐o‐CH2SCH3)3BiX3], (X=Cl, Br, I) have been synthesised and characterised. The strength of the weak and mainly electrostatic interaction between the Bi and P centres strongly depends on the character of the halogen substituent on bismuth, which is confirmed by single‐crystal X‐ray diffraction analyses, DFT and ab initio computations. Significantly, 209Bi–31P through‐space coupling (J=2560 Hz) is observed in solid‐state 31P NMR spectra, which is so far unprecedented in the literature, delivering direct information on the magnitude of this pnictogen interaction

Naphthyl-Fused Phosphepines: Luminescent Contorted Polycyclic P-Heterocycles

The article presents the synthesis of a new family of naphthyl-fused phosphepines through Ni-mediated C-C coupling. Interestingly, the chloro-phosphine-oxide intermediate shows strong resistance toward oxidation/hydrolysis due to a combination of steric hindrance and pnictogen interactions. However it can undergo substitution reactions under specific conditions. The optical / redox properties and the electronic structure of these new pi-systems were studied experimentally and computationally. Taking advantage of the luminescence of these derivatives, a blue emitting OLED has been prepared highlighting that these novel pi-conjugated P-heterocycles appear as promising building blocks for solid-state lightning applications

Naphthyl-Fused Phosphepines: Luminescent Contorted Polycyclic P-Heterocycles

the article presents the synthesis of a new family of naphthyl-fused phosphepines through Ni-mediated CC coupling. Interestingly, the chloro-phosphine-oxide intermediate shows strong resistance toward oxidation/hydrolysis due to a combination of steric hindrance and pnictogen interactions. However it can undergo substitution reactions under specific conditions. The optical / redox properties and the electronic structure of these new $\pi$-systems were studied experimentally (UV-vis absorption, emission, cyclic voltammetry) and computationally (TD-DFT calculations, NICS investigation). Taking advantage of the luminescence of these derivatives, a blue emitting OLED has been prepared highlighting that these novel $\pi$-conjugated P-heterocycles appear as promising building blocks for solid-state lightning applications