Study of a rigid-chain dendrimer by inverse gas chromatography

A fourth-generation rigid-chain pyridine-containing polyphenylene dendrimer is studied by inverse gas chromatography. Two types of sorbates are investigated: C₇-C₁₁ n-alkanes and C₆H₆-C₆H₅C₅H₁₁ alkylbenzenes. In the range 35−150°C, specific retention volumes of the indicated sorbates are measured and their solubility coefficients are calculated. It is shown that aliphatic sorbates exhibit reduced solubility coefficients in the aromatic dendrimer compared to those observed for aliphatic polymers and the earlier studied carbosilane dendrimer. At the same time, alkylbenzenes are characterized by enhanced solubility coefficients and this effect is more pronounced for the first members of the homologous series. An analysis of excess partial molar thermodynamic functions shows that π-electron interactions in the dendrimer and among dendrimer and aromatic sorbates are responsible for the thermodynamic properties of the dendrimer under study.