Weak Effect on T c with Increased Interchain Distances. Structure and Magnetic Properties of (meso-Tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphinato)manganese(III) Tetracyanoethenide, [MnIIITP‘P]+[TCNE]•-

• Published in: Inorganic chemistry 1996-05, Vol.35 (11), p.3083-3088
• Main Authors: Böhm, Arno, Vazquez, Carlos, McLean, R. Scott, Calabrese, Joseph C, Kalm, Sandra E, Manson, Jamie L, Epstein, Arthur J, Miller, Joel S
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic9516267

(meso-Tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphinato)manganese(III) tetracyanoethenide, [MnTP‘P][TCNE], has been structurally and magnetically characterized. [MnTP‘P][TCNE] (C96H108MnN8O4) belongs to the triclinic P1̄ (No. 2) space group with a = 8.597(2) Å, b = 14.756(4) Å, c = 17.573(5) Å, α = 101.16 (2)°, β = 100.56(2)°, γ = 96.37(2)°, and Z = 1. Due to the oxidative instability of the phenoxy groups, [MnIIITP‘P][TCNE] was prepared from the reaction of [MnIIITP‘P]OAc with the strong acid H2TCNE (pK a = 3.6) in the presence of TCNE to form acetic acid and the product. [MnTP‘P][TCNE] is a coordination polymer with the Mn(III) sites bridged by trans-μ2-bound [TCNE]•- with relatively short (8.587 Å) intrachain and long (≥14.756 Å) interchain Mn···Mn separations. The magnetic data above 210 K obey the Curie−Weiss expression with an effective ϑ value of 90.0 K, the largest yet reported for a soluble molecule-based magnet. In addition to a 15 K T c hysteretic behavior with a coercive field of 100 Oe is observed at 5 K. Despite the significant steric bulk leading to the substantially decreased interchain interactions that are crucial for magnetic ordering, the T c is unexpectedly high and suggests that other linear chain systems may be expected to exhibit magnetic ordering at higher temperatures.