Abstract
The (tert-butyl isocyanide)(5,10,15,20-{tetrakis-[4-(benzoyloxy) phenyl] porphyrinato} iron(II) coordination compound with the formula [Fe-II(TPBP)(t-BuNC)(2)] (I) was prepared by the reduction of the triflato iron(III) starting material [Fe-III(TPBP)(SO3CF3)] using a large excess of tert-butyl isocyanide. The UV-visible titration and IR spectra indicated that (I) is an iron(II) porphyrin derivative. A solid-state Mossbauer investigation of this species showed that the quadrupole splitting (Delta E-Q) and the isomer shift (delta(Fe)) values are small [Delta E-Q - 0.20 (1) mm. s(-1) and delta(Fe) - 0.22 (1) mm. s(-1) at 300 K]. These values are very close to those of the known bis(carbonyl) and the bis(cyano) iron(II) porphyrins. This indicates that (I) is a low-spin (S = 0) iron(II) metalloporphyrin where the t-BuNC is a good pi-acceptor moiety comparable to the CN- and CO ligands. The X-ray molecular structure confirms the low-spin character of (I) where the average equatorial Fe(II)-N(pyrrole) bond length is 2.007 (2) angstrom. In the crystal, the [Fe-II(TPBP)(t-BuNC)(2)] molecules are linked together via weak C-H center dot center dot center dot center dot O and C-H center dot center dot center dot center dot Cg (Cg is the centroid of a pyrrole or a phenyl ring) intermolecular interactions forming two-dimensional chains parallel to the c axis. (C) 2017 Elsevier B.V. All rights reserved.