Borderland Theory as a Conceptual Framework for Comparative Local US and Canadian History

A double-helical S,C-bridged tetraphenyl-para-phenylenediamine and its persistent radical cation

“…We synthesized 4 in three steps from diethyl 2,5-dibromoterephthalate as shown in Scheme S1 (ESI †). 11 In the 1 H NMR spectrum of 4, two sets of signals for the Ha, Hb, and Hc protons of the two diastereomers, i.e., the meso compound (meso-4) and the racemate (rac-4), were observed on the NMR timescale (Fig. S2, ESI †).…”