PREPARATION OF PHOSPHORUS-CONTAINING AND FLUORINE-CONTAINING CALIX[4]ARENE DERIVATIVES - CONFORMATIONAL-ANALYSIS, SEPARATION OF THE CONFORMERS, AND X-RAY CRYSTAL-STRUCTURE ANALYSIS OF A CONE CONFORMER

The Calix[4]arene 1 reacts with hexamethyldisilazane or (diethylamino) trimethylsilane to form the bis-trimethylsilylated derivative 2. Treat ment of 2 with PF2Cl gives the monoand bis-difluorophosphites 3 and 4, which react with elimination of Me(3)SiF or PF3 to yield the monofluo rophosphite derivative 5. All four OH hydrogen atoms in 1 are replaced by lithium on reaction with nBuLi with formation of the tetralithiate d product 6. This has been allowed to react with the P-chlorophosphori nanones 7-9. From 7 the cone conformer 10a is formed, whereas in the e ase of 8 and 9 a mixture of all four possible conformers 11a-d and 12a -d is obtained. The pure conformers 12a-d are isolated. By refluxing t he cone conformer 12a in tetrachloroethane a conformational conversion is effected. In order to evaluate its coordinating ability, 12a was a llowed to react with dichloro(cycloocta-1,5 diene)platinum(II) to form the trans-disubstituted complex 13. In the case of 12a (acetonitrile solvate) a single-crystal X-ray structure analysis has been conducted. The molecule displays a cone conformation, whereby two of the opposin g phenyl rings are approximately parallel and the other two approximat ely perpendicular to each other.