title: Structural characteristics for phase transitions of [N(CH3)4]2CuCl4 by (13)C CP/MAS NMR and (14)N NMR.
abstract: Structure geometry changes in [N(CH3)4]2CuCl4 near the phase transition temperature were studied by (13)C CP/MAS NMR and (14)N NMR spectrum. We distinguished the two chemically inequivalent N(1)(CH3)4 and N(2)(CH3)4 groups by (13)C CP/MAS NMR and (14)N NMR spectrum. The abrupt changes in chemical shifts and the split of the NMR signals near the phase transition temperatures for (13)C and (14)N are explained by a structural phase transition, implying that the structural geometry depends on the temperature. The mechanism behind this phase transition is based on ferroelasticity, and is also mainly related to the (14)N ions in N(CH3)4 ions. Furthermore, both phases III and IV exhibit ferroelastic properties with identical orientational domains.
authors.affiliation: Department of Carbon Fusion Engineering, Jeonju University, Jeonju 560-759, Republic of Korea.
authors.forename: Nam
authors.initials: N
authors.lastname: Hee Kim
authors.affiliation: Department of Science Education, Jeonju University, Jeonju 560-759, Republic of Korea; Department of Carbon Fusion Engineering, Jeonju University, Jeonju 560-759, Republic of Korea. Electronic address: aeranlim@hanmail.net.
authors.forename: Ae Ran
authors.initials: AR
authors.lastname: Lim
keywords: Ferroelasticity; Magic-angle spinning; Nuclear magnetic resonance; Phase transition; [N(CH(3))(4)](2)CuCl(4)