Systematic investigation of an array of TCNQ lanthanide complexes: synthesis, structure and magnetic properties.
An array of TCNQ (TCNQ = 7,7,8,8-tetracyano-p-quinodimethane) lanthanide complexes, namely, [Ln2(TCNQ)4(H2O)10(EtOH)2][2TCNQ] x xH2O [Ln = La (1, x = 5), Pr (2, x = 3)], [Ln2(TCNQ)4(H2O)10][2TCNQ] x yH2O [Ln = Gd (3, y = 6), Dy (4, y = 5)] and [Ln(TCNQ)2(H2O)6][TCNQ] x H2O x MeOH [Ln = Er (5), Lu (6)], have been synthesized by salt-elimination reactions. X-ray crystallographic analysis indicates that 1-6 are discrete ion complexes. Cations of 1-4 adopt a dimer structure, while cations of 5 and 6 display a monomer structure. The magnetic study proposes that an antiferromagnetic interaction between TCNQ radicals exists in 1-6. The depopulation of the Stark levels for 2 and 5 leads to a continuous decrease in mT when the samples are cooled from 300 K to 2 K. The desolvated 3, namely, 3a exhibits a unique magnetic conversion from the magnetic disordering to the magnetic ordering at 4 K. 4 shows a ferromagnetic coupling between paramagnetic centers.
Zhang
Juwen
J
Key Laboratory of Functional Inorganic Material Chemistry (Heilongjiang University), Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, No. 74, Xuefu Road, Nangang District, Harbin, 150080, PR China.
Yan
Pengfei
P
Li
Guangming
G
Hou
Guangfeng
G
Suda
Masayuki
M
Einaga
Yasuaki
Y