Formation of Charge-Transfer Complexes from Neutral Bis(porphyrin) Sandwiches

Abstract

Lanthanide(III) bis(porphyrin) sandwich complexes of octaethyltetraazaporphyrin (OETAP) were synthesized and characterized by UV-vis, IR, and NMR spectroscopies. Cyclic voltammetry results indicate that these neutral sandwich complexes are very easily reduced. Charge-transfer reactions were performed in solution with Ln-(OETAP)2 sandwiches and zirconium(IV) bis(porphyrin) sandwiches. The lanthanide sandwiches partially oxidize the zirconium sandwiches in solution, and a solvent dependence of the charge-transfer reaction was observed. The solid-state properties of these charge-transfer materials were also studied. Magnetic susceptibility results suggest weak intermolecular interactions between the sandwiches. The conductivities of the charge-transfer species are greatly improved relative to those of the insulating undoped sandwiches, but the conductivities are in the lower semiconducting region. The low conductivity values are thought to be due to poor intermolecular overlap.

Multistate molecular information storage using S-acetylthio-derivatized dyads of triple-decker sandwich coordination compounds

“…An alternative route employs the templated synthesis of a phthalonitrile with Eu(acac) 3 ·nH 2 O and DBU in refluxing 1-pentanol [33]. Regardless of synthetic method, the double-decker complex of a lanthanide such as europium typically consists of a mixture of a protonated form (blue) and a π-radical form (green) [34,35]. The separation of such forms often is difficult; the mixture can be used directly or treated to convert one form into the other.…”

Developments in the metal chemistry of N-confused porphyrin

“…However, in certain circumstances dimeric complexes can form. This is observed for large metal ions which do not fit well in the pore of the macrocycle, as in Zr(TPP) 2 and U(TPP) 2 [57][58][59][60]. Alternatively, there are many examples where metal-metal bond formation promotes dimerization, as seen in [Rh(TPP)] 2 and [Ru(TPP)] 2 [61][62][63].…”

DFT/TDDFT Study of LanthanideIII Mono- and Bisporphyrin Complexes

“…26 Compared to analogous monoporphyrins, there are two notable features of M(Por) 2 : a blue shift of the B (or Soret) bands and a decrease in the oxidation potential. 16,17 In addition, the porphyrin sandwich compounds have a number of characteristic optical properties that are not exhibited by mono-porphyrins or dimers having larger spacing between the rings. For example, Ln III (Por) 2 or the π-radical cations, [M IV (Por) 2 ] + (formed by oxidation), exhibit an intense broad band in the near-IR region (1000 -1400 nm) 20,22 not found in simple MPor or [MPor] + .…”