Efficient synthesis and magnetic properties of triphenylamine bearing three nitronylnitroxide radicals

Abstract: Improved synthesis and reinvestigation of the magnetic properties of triphenylamine bearing three nitronylnitroxide radicals (1) were carried out. Single crystal X-ray crystallographic analysis of 1 established that its molecular shape had a C 3-symmetry. Our newly prepared 1 showed different physical properties from those of reported. SQUID measurements of 1 showed that each of the three spins of 1 behaved independently at room temperature. In contrast, the three spins coupled antiferromagnetically at lower temperature as low as ca. 1.8K. These spin behaviors can be explained by a regular triangular antiferromagnetic model (J/k B =−3.3K) and interpreted as a spin frustration system. [Copyright &y& Elsevier]