Asymmetric bis-(μ_1,1-azido) bridged dinuclear copper(II) complex with N₂O donor Schiff base: synthesis, structure and magnetic study

Abstract

A copper(II) complex, [Cu₂(L)₂(N₃)₂] [where HL = 2-((3-(methylamino)propylimino)methyl)-6-methoxyphenol] has been synthesized and characterized by elemental analysis, IR, UV–vis and fluorescence spectroscopy, and single-crystal X-ray diffraction studies. The complex crystallizes in the trigonal space group R. The deprotonated tridentate Schiff base occupies three coordination sites of copper(II). The fourth coordination site is occupied by an azide. A symmetry-related azide from a different molecule coordinates with the fifth site of copper(II), thereby forming a double end-on azide-bridged centrosymmetric dimer. Variable temperature solid–state magnetic studies between 2 and 300 K were carried out and the data indicate predominant antiferromagnetic exchange interactions with 2J = –0.45 cm⁻¹. The magnetic field-dependent magnetization study (M − H) reveals existence of antiferromagnetic ordering at a lower temperature (2 K) with a very small coercive field (~20 Oe) suggesting soft magnet behavior of the complex.

A double end-on azide-bridged centrosymmetric dinuclear copper(II) complex, [Cu₂(L)₂(N₃)₂], has been synthesized and characterized. X-ray crystal structure analysis has confirmed the structure; variable temperature (2–300 K) magnetic susceptibility measurement indicates antiferromagnetic exchange interactions with 2J = –0.45 cm⁻¹.

Keywords:

• Schiff base
• Copper(II)
• Dinuclear
• Antiferromagnetic
• Field-dependent magnetization study

Acknowledgments

SC acknowledges DST, India under FAST Track Scheme (Order No. SR/FT/CS-118/2010, dated 15/02/2012). SKS acknowledges DST, India (project No. SR/NM/NS-1089/2011) for providing facilities of magnetic measurements. BKS acknowledges CSIR, New Delhi, for awarding fellowship.