Synthesis and Crystal Structure of Bis[2-(2-imidazolinyl)-6-methoxyphenolato]zinc(II)

High-spin octahedral or pseudo-tetrahedral cobalt(II) complexes have been attracting much attentions because they are potential candidates for single-ion magnets (SIMs).1–4 Although many SIMs with a first-row transition-metal have been reported,5 most of them do not exhibits a slow magnetic relaxation behavior in the absence of an external field due to fast relaxation via quantum tunneling. To prepare a zero-field SIM, not only a strong magnetic anisotropy, but also the molecular alignment of SIMs in the crystal, is important. Recently, zero-field SIM behavior in pseudo-tetrahedral cobalt(II) complexes with 2-(2-imidazolinyl)-6-methoxyphenolate (Hmimn–) was reported.4 It was suggested that hydrogen-bonded chain networks of [Co(Hmimn)2] play a crucial role for slow magnetic relaxation in the absence of an external field. To elucidate the correlation between intermolecular magnetic coupling and quantum tunneling of magnetization, partial substitution of a paramagnetic ion by a diamagnetic ion in the crystal is an effective method. For such magnetic dilution experiments, it is important to prepare a diamagnetic analogue which is isomorphic to the SIM. In this study, an isomorphic Zn complex analogue of [Co(Hmimn)2]·CH3OH, [Zn(Hmimn)2]·CH3OH, was prepared and crystallographically characterized (Fig. 1). The ligand precursor 2-(2-imidazolinyl)-6-methoxyphenol (H2mimn) was synthesized according to a previously reported procedure.4 The title compound was obtained as colorless crystals from a reaction of ZnCl2 (13.6 mg, 0.10 mmol), H2mimn (38.4 mg, 0.20 mmol) and triethylamine (30 μL) in 10 mL methanol. Yield: 38.9 mg (81%). The crystal data are included in Table 1. X-ray crystallographic data were collected on a Rigaku HyPix AFC diffractometer at 100(2)K. The integrated and scaled data were empirically 2021 © The Japan Society for Analytical Chemistry