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JOURNAL OF MATERIALS CHEMISTRY, vol.5, no.12, pp.2257-2264, 1995 (SCI-Expanded)
Two series (4 and 5, each with three members) of a new family of metallomesogens have been synthesized starting from the bisimine ligands 1 and 2 and the dichloroplatinum compound 3. These one-pot reactions of 1 or 2 with 3 leading to 4a and 5a, respectively, give insights into possible self-assembly processes and constitute the first examples of four-fold o-platinations in organic chemistry. The two pairs of halogen homologues 4b,c and 5b,c are then obtained by the usual exchange of the four central chlorine bridges in their parent compounds 4a or 5a, respectively, using the corresponding alkali-metal halides (potassium bromide, lithium iodide) in organic solvents at room temperature. Furthermore, we report on the mesomorphism of these first tetraplatinum organyls (applying a new system of mesophase notation for materials with sheet-like molecular structure) and describe some of their unusual lyotropic (including charge-transfer-induced chiral nematic) properties in apolar organic solvents in which, e.g., two nematic-columnar phases can be observed side by side.