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 -C 6 H 4 O(CH 2 ) 6 O 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 -C 6 H 4 group ( 3a ) are reacted with the hexatriynyl complex trans -(C 6 F 5 )( p -tol 3 P) 2 Pt(C≡C) 3 H (1.0:2.5 mol ratios) in the presence of K 2 CO 3 (4.0–5.0 equiv) and I 2 (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 -(C 6 F 5 )( p -tol 3 P) 2 Pt(C≡C) 6 Pt(P p -tol 3 ) 2 (C 6 F 5 ) ( 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 (C 8 ) analogs, and their spectroscopic properties and crystal structures are analyzed in detail, especially with reference to recent DFT studies.