Synthesis and Solid-State Structural Analysis of Exotetradentate Ligands Based on Mesitylene-Derived [1.1.1.1]Metacyclophane Fixed in a 1,3-Alternate Conformation

Abstract

A series of new tetradentate ligands based on the [1.1.1.1]metacyclophane backbone fixed in a 1,3-alternate conformation was achieved. For the strategy developed, the common synthon for the preparation of twelve ligands bearing four interaction sites occupying the apices of a pseudo-tetrahedron [H, SH, CN, SCH3, CO2H, CHO, PPh2, P(O)Ph2, NO2, NH2, pyridine, and para-methoxyphenyl] was the tetrabromo derivative 7. In addition to the classical characterisation methods applied to all reported ligands, compounds 7, 9, 12, and 13 were structurally studied in the solid state by single-crystal X-ray diffraction, which indeed confirmed their 1,3-alternate conformation.