A new molecular magnetic semiconductor based on tetrathiafulvalene (ttf) and oxamato ligand (opba): [ttf]2[Cu(opba)]·H2O

Journal of the Brazilian Chemical Society

Universidade Federal de Minas Gerais, Belo Horizonte, Brazil¹  Sansiviero, Maria T. C.¹  Universidade Estadual Campinas, Campinas, Brazil¹  Mambrini, Raquel V.¹  Centro Federal de Educação Tecnológica do Espírito Santo, Vitória, Brazil¹  Stumpf, Humberto O.¹  Knobel, Marcelo¹  Matencio, Tulio¹  Dias, Mauro C.¹ 

关键词: tetrathiafulvalene;    molecular magnetism;    semiconductor;    oxamato ligand;    molecular spintronics;   

DOI  :  10.1590/S0103-50532010000700015

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

An oxamato-based compound of formula [ttf]2[Cu(opba)]·H2O, with ttf = tetrathiafulvalene and opba = ortho-phenylenebis(oxamato), has been prepared and characterized. The complex was obtained by metathesis from (ttf)3(BF4)2 and (Bu4N)2[Cu(opba)] in acetonitrile at room temperature. The UV-Vis-NIR spectrum reveals the presence of the radical cation in two forms, (ttf •+) and (ttf •+)2 dimer. The electronic transport properties of [ttf]2[Cu(opba)]·H2O were studied by impedance spectroscopy (IS) and linear voltammetry (LV), and show a typical semiconductor behavior. The EPR spectra exhibit two superposed lines corresponding to electron spins of CuII ions and ttf •+ radical cations. The dc magnetic properties show a room temperature value of the χMT product close to that expected for three uncoupled S = ½ spins and a value of 0.13 emu K mol-1 at low temperature (4 K). The χMT vs. T curve was fitted and the best model consists of a term for a (ttf •+)2 dimer (Bleaney-Bowers, leading to J2 = -186 cm-1) and a second term related to an antiferromagnetic {Cu···ttf •+} chain (J1 = -10.1 cm-1).

【 授权许可】

Unknown