Synthesis and Optical Property Modulation of Substituted [2,2]-paracylophanes through Through-Space Conjugation

4,16-para-substituted [2,2] paracylophane with naphthalene (PCP-NAP), anthracene (PCP-ANTH), and tetraphenylethylene (PCP-TPE) as a new through-space conjugated dimers were prepared by the Suzuki–Miyaura cross-coupling reaction of 4,16-diboryl [2,2] paracyclophane and respective bromo derivative using Pd(PPh3)4 as a catalyst and KOH as a base. The synthesized compounds were fully characterized by NMR, HR-MS and their photophysical, and electrochemical properties were studied. The quantum yield of PCP-NAP and PCP-ANTH were calculated and estimated as 0.21 and 0.50. PCP-TPE exhibited aggregation-induced emission characteristics when the water fraction was higher than 40% in the THF/water mixtures, it crystallizes in the centrosymmetric triclinic space group P⎼1 with one molecule residing on the inversion centre. The observed properties of these π-stacked dimers were compared to conjugation length in the structure.