The quantum effects that determine the SF rate with anthracene as the bridge molecule are more complex. The relatively small 𝜏 !" in the DQI compounds here are ascribed to two competing quantum effects. First, the absence of long-range antiferromagnetic order in one dimension implies that, for long bridge molecules, spin couplings between distant atoms are not strictly antiferromagnetic or ferromagnetic. As a result, CT between carbon atoms at the point of connectivity that would be forbidden from the graphical model of These results explain our observation of only a ~4-5× change in 𝜏 !" between the CQI 26A compounds and the DQI 27A compounds. Furthermore, while SF in DQI P-27A-P is relatively slow, it is still significantly faster than in T-27N-T and P-27N-P.