Work by Cotton and others have shown that formamidinates are versatile ligands for stabilizing a wide range of metal-metal bonded complexes. These complexes typically adopt the familiar paddle wheel geometry common among dimetal tetracarboxylate complexes. However, unlike carboxylate ligands, formamidinates may be derivatized in order to tune their steric and electronic properties. Our objective is to replace the typical aryl substituents with thiazole and pyrazole groups. It is anticipated that these functionalized substituents will provide donor sites that may incorporate additional metal ions creating linear arrays of metal ions. To this end, we have successfully synthesized and characterized the di-functionalized formamidines: N,N’-dithiazolylformamidine (HDtzF), N,N’-dibenzothiazolylformamidine (HDbtzF), and N,N’-dipyrazolylformamidine (HDpzF). Each substituted formamidine was prepared in good yield by reaction of two equivalents of the appropriate amino-substituted derivative, 2-aminothiazole, 2-aminobenzothiazole, and 3-aminopyrazole, respectively, with triethylorthoformate. <sup>1</sup>H NMR spectroscopy reveals that each of these functionalized formamidines exhibits fluxional behavior in solution. Details of the synthesis, structure, and spectroscopic characterization of each disubstituted formamidine will be presented together with their preliminary reactions with rhodium acetate.

Development of new dithiazolyl and dipyrazolyl substituted formamidinate ligands for the stabilization of bimetallic and tetrametallic complexes

255th National Meeting (2018)

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