title: Synthesis and Electrochemistry of Tin(IV) Octaethylcorroles, (OEC)Sn(C(6)H(5)) and (OEC)SnCl.
abstract: Two Sn(IV) corroles were synthesized and electrochemically examined. The investigated compounds are represented as (OEC)Sn(C(6)H(5)) and (OEC)SnCl, where OEC = trianion of 2,3,7,8,12,13,17,18-octaethylcorrole. (OEC)Sn(C(6)H(5)) represents the first example of a sigma-bonded metallocorrole which does not undergo a metal-centered electrode reaction. Both compounds undergo three reversible one-electron oxidations, all of which occur at the conjugated macrocycle. The reduction of (OEC)SnCl involves an overall two electrons, with the product being spectroscopically identified as a Sn(II) corrole after bulk electrolysis of the starting compound. (OEC)Sn(C(6)H(5)) is reversibly reduced by a single electron to give a Sn(IV) corrole pi-anion radical. The electrochemically measured HOMO-LUMO gap (defined as the absolute potential difference between the first-ring centered reduction and first ring-centered oxidation) is equal to 2.25 V in benzonitrile, a value which closely approximates what is observed for porphyrins containing octaethylporphyrin (OEP) or tetraphenylporphyrin (TPP) macrocycles. An X-ray crystallographic analysis for the molecular structure of (OEC)Sn(C(6)H(5)) is also presented: monoclinic, P2(1)/n, with a = 13.235(4) Å, b = 14.502(4) Å, c = 18.387(5) Å, beta = 95.45(2) degrees, Z = 4, R = 0.0619.
authors.affiliation: Department of Chemistry, University of Houston, Houston, Texas 77204-5641, and Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50939 Köln, Germany.
authors.forename: Karl M.
authors.initials: KM
authors.lastname: Kadish
authors.forename: Stefan
authors.initials: S
authors.lastname: Will
authors.forename: Victor A.
authors.initials: VA
authors.lastname: Adamian
authors.forename: Burkhard
authors.initials: B
authors.lastname: Walther
authors.forename: Christoph
authors.initials: C
authors.lastname: Erben
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Ou
authors.forename: Ning
authors.initials: N
authors.lastname: Guo
authors.forename: Emanuel
authors.initials: E
authors.lastname: Vogel