Synthesis of and evidence for electronic communication within heteromultimetallic Tetrakis(NCN-pincer metal) - (Metallo)porphyrin Hybrids

Several heteromultimetallic pincer-porphyrin hybrids have been prepared in excellent yields by stepwise metalation of a general precursor, [2H(Br(NCN))4], which was designed in such a way so as to guarantee selectivity for either the porphyrin or pincer sites during themetalation steps. First, ametal was introduced in the porphyrin cavity using ametal(II) salt, followed bymetalation of the pincer units through oxidative addition to an appropriate metal(0) complex. The resulting multimetallic complexes show an appreciable amount of intramolecular communication between the meso-pincer metal groups and the centralmetalloporphyrin component. Thiswasmanifested in changes of the optical and ligandbinding properties of the metalloporphyrin part upon reactions at the peripheral pincer sites.