Phosphetene-based polyaromatics: structure-property relationships and chiroptical tuning.

We describe the synthesis of π-extended phosphetene rings (4-member P-rings) flanked with PAH systems of various topologies. These compounds are fully characterized including X-ray diffraction. The impact of both the polyaromatic platform and the P-ring on the structure, and the optical and redox properties are investigated both experimentally and theoretically. Although neither the P centre nor the 4-membered ring significantly takes part in the HOMO or LUMO orbitals, both structural features have an important modulating role in distorting the symmetry of the orbitals, leading to chiroptical properties. The stereogenic P-atom is used as a remote chiral perturbator to induce circularly polarized luminescence of the polyaromatic system. The dissymmetry factor is highly dependent on the polyaromatic topology, as supported by theoretical calculations.

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

We 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.

Generation and trapping of a terminal chlorophosphinidene complex.

The system (1-chloro-3,4-dimethylphosphole)pentacarbonyltungsten + dimethyl acetylenedicarboxylate generates (chlorophosphinidene)pentacarbonyltungsten at 60-70 degrees C via the 7-phosphanorbornadiene complex. This phosphinidene reacts with alkynes, alkenes, and conjugated dienes to give the corresponding chlorophosphirene, chlorophosphirane, and chlorophospholene complexes. A single isomer has been obtained in the cyclohexene case.