Strongly coupled porphyrin arrays featuring both π-cofacial and linear-π-conjugative interactions

A combination of metal-catalyzed cross-coupling and metal-templated cycloaddition reactions have been utilized to establish multiporphyrin compounds 5-(5′-[15′,15″-bis(10″,20″-di[4- (3-methoxy-3-methylbutoxy)phenyl]porphinato)zinc(II)]ethyne)-6- [(5‴-10‴,20‴-di[4-(3-methoxy-3-methylbutoxy) phenyl]porphinato)zinc(II)]indane (1) and 5,6-bis(5′-15′,15″-bis[(10′,20′-di[4- (3-methoxy-3-methylbutoxy)phenyl]porphinato)zinc(II)]ethyne)indane (2). Compounds 1 and 2 feature a covalently bridged cofacial bis(porphinato) metal core; ethyne bridging moieties conjugate directly one and two respective peripheral (porphinato)zinc(II) substituents to the macrocyclic framework of their corresponding face-to-face porphyrin units. Optical spectroscopy and electrochemical studies demonstrate substantive electronic interactions between the porphyrin subunits of these compounds. Notably, structural and ¹H NMR analyses verify that 1 and 2 possess open conformations necessary for binding small molecules within their respective cofacial (porphinato)metal cores.