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, [Mn(III)TP'P](+)[TCNE](*-).
(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] (C(96)H(108)MnN(8)O(4)) belongs to the triclinicP&onemacr; (No. 2) space group with a = 8.597(2) Å, b = 14.756(4) Å, c = 17.573(5) Å, alpha = 101.16 (2) degrees, beta = 100.56(2) degrees, gamma = 96.37(2) degrees, and Z = 1. Due to the oxidative instability of the phenoxy groups, [Mn(III)TP'P][TCNE] was prepared from the reaction of [Mn(III)TP'P]OAc with the strong acid H(2)TCNE (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-&mgr;(2)-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 &THETAV; 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.
Böhm
Arno
A
Science and Engineering Laboratories, Experimental Station, E328, Du Pont, Wilmington, Delaware 19880-0328, Departments of Physics and Chemistry, The Ohio State University, Columbus, Ohio 43210-1106, Bard College, Annandale-on-Hudson, New York 12504, and Department of Chemistry, University of Utah, Salt Lake City, Utah 84112.
Vazquez
Carlos
C
McLean
R. Scott
RS
Calabrese
Joseph C.
JC
Kalm
Sandra E.
SE
Manson
Jamie L.
JL
Epstein
Arthur J.
AJ
Miller
Joel S.
JS