Rotaxanes Derived from Dimetallic Polyynediyl Complexes: Extended Axles and Expanded Macrocycles

A new 35-membered macrocycle 3b derived from 1,10-phenanthroline and two 2,9-p-C6H4O­(CH2)6O substituents that tether a 2,7-naphthdiyl moiety is synthesized. CuI complexes of 3b and a previously reported analog in which the naphthdiyl is replaced by a m-C6H4 group (3a) are reacted with the hexatriynyl complex trans-(C6F5)­(p-tol3P)2Pt­(CC)3H (1.0:2.5 mol ratios) in the presence of K2CO3 (4.0–5.0 equiv) and I2 (1.3–1.8 equiv) in THF at 55 °C. Workups afford the rotaxanes 5·3a and 5·3b (45–23%), in which the macrocycles are threaded by the sp carbon chain of the diplatinum dodecahexaynediyl complex trans,trans-(C6F5)­(p-tol3P)2Pt­(CC)6Pt­(Pp-tol3)2(C6F5) (5), which is also obtained as a byproduct. The yields of 5·3a and 5·3b are much higher than in the case with octatetraynediyl (C8) analogs, and their spectroscopic properties and crystal structures are analyzed in detail, especially with reference to recent DFT studies.