PHOTOINDUCED ELECTRON-TRANSFER IN PORPHYRIN-QUINONE CYCLOPHANES, 17 -DISTANCE DEPENDENCE OF PHOTOINDUCED ELECTRON-TRANSFER - SYNTHESES ANDPROPERTIES OF BIPHENYLENE-SPACERED PORPHYRIN-QUINONE CYCLOPHANES

In continuation of previous syntheses of benzene- naphthalene-, and an thracene-spacered porphyrin-quinone cyclophanes 1, 2, and 4, biphenyle ne-spacered porphyrin- quinone cyclophanes of structure 3 as the ''mis sing link'' between 2 and 4 were prepared in multistep syntheses. Thes e donor-acceptor systems are of interest since, with regard to electro n-transfer rates, they complete the series of 1, 2, and 4, As expected the electron-transfer of 3 proceeds 1, 2, and 4, As expected the elec tron-transfer of 3 proceeds between that of 2 and 4 in an especially s teep region of distance dependences of electron-transfer rates.