Synthesis and Complexation of “Back-to-Back” Capped Bis-dioxocyclams

Pyridine-capped 5,12-dioxocyclams were coupled “back-to-back” directly, with one or two intervening phenyl groups,
an ethynyl group, or a diazo group via Suzuki, Sonogashira, or reductive coupling of the 4-nitropyridine monocyclam.
These bis-dioxocyclams linked through extended π-conjugated systems were complexed to copper(II) and cobalt(III), producing bis-metal complexes which were characterized spectroscopically and electrochemically. These studies
gave little evidence for electronic communication between metal centers across the π-conjugated linkers.

吡啶封端的5,12-二氧环胺（Pyridine-capped 5,12-dioxocyclams）可直接以"背对背"方式偶联，或通过铃木（Suzuki）、薗头（Sonogashira）偶联反应，抑或借助4-硝基吡啶单环胺的还原偶联，接入1个或2个间隔苯基、乙炔基或重氮基。这类通过扩展π共轭体系（π-conjugated systems）连接的双二氧环胺，可与二价铜（copper(II)）和三价钴（cobalt(III)）配位得到双金属配合物，随后通过光谱学与电化学手段对其完成表征。上述研究未观测到金属中心间通过该π共轭连接桥存在电子通讯的明确证据。