Synthesis and characterization of 1,1’-ferrocenic aryl carbonic and thiocarbonic anhydrides

Abstract

The reactivity of 1,1′-ferrocenedicarboxylic acid (FcDA) toward aryl chloroformates and O-aryl chlorothioformates has been investigated to access novel ferrocene-derived (aryl carbonic) and (aryl thiocarbonic) anhydrides. The reactions of FcDA with phenyl and p-tolyl chloroformates in the presence of triethylamine afforded the corresponding bis(aryl carbonic) anhydrides, Fc(CO₂CO₂Ar)₂ [Fc = 1,1′-(C₅H₄)₂Fe; Ar = C₆H₅ (1a), p-C₆H₄CH₃ (1b)]. Similarly, treatment of FcDA with the analogous O-aryl chlorothioformates yielded bis(aryl thiocarbonic) anhydrides, Fc(C(O)SCO₂Ar)₂ [Ar = C₆H₅ (2a), p-C₆H₄CH₃ (2b)]. All compounds were characterized by UV–Vis, IR, ¹H-, and ¹³C{¹H}-NMR spectroscopy. Structural elucidation was further achieved by single-crystal X-ray diffraction, confirming the molecular architectures of the synthesized anhydrides. Density functional theory (DFT) calculations were performed at the PBE0/def2-TZVP level with CPCM solvation to further elucidate the electronic structures of the complexes. These theoretical results support the experimental UV–Vis data, offering insights into the nature of the observed electronic transitions and the frontier molecular orbitals involved.