Syntheses, structures, and properties of intercalation compounds of silver(1) complex with [2.2]paracyclophane

Reaction of [2.2]paracyclophane (pcp) with silver(l) trifluoroacetate (AgCF3CO2) and silver(l) pentafluoroproprionate (AgC2F5CO2) has led to isolation of three novel intercalation polymers: [Ag-4(PCP)(CF3CO2)(4)](C6H6) (1), [Ag-4(pcp)(CF3CO2)(4)](C6H3Me3) (2), and [Ag-4(PCP)(C2F5CO2)(4)](PCP) (3). Structure studies using single crystal X-ray diffraction have shown that all compounds contain two-dimensional layered frameworks based on cation-pi interactions, in which pcp exhibits an unprecedented mu-tetra-eta(2) Coordination mode. Guest molecules which weakly interact with the host pcp via C-H(...)pi interactions are intercalated between layers. The guest-eliminated complexes (1a and 2a) and guest-reincorporated ones (1b or 1c and 2b or 2c), accompanied by small structural changes, were confirmed by H-1 NMR, thermogravimetric analysis, mass spectra, and X-ray powder diffraction patterns. The structural changes from 1 --> 1a --> 1c (=11) can take place reversibly in the process of exposure of 1 a to benzene vapor, The original framework of complex 2 is also completely recovered by immersing 2a in mesitylene as well as exposing it to mesitylene vapor.