The Field-Dependent Magnetization of d5-d7 Metal β−Diketonate Complexes and Their Macromolecular Polymers

• Published in: Journal of macromolecular science. Physics 2014-07, Vol.53 (7), p.1258-1269
• Main Authors: Al-Anber, Mohammed A., Daoud, Haneen, Lataifeh, Mahdi
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Inorganic and organomineral polymers; magnetic properties; metal acetates, paramagnetic transition metals; metal β−diketonate polymers; Physicochemistry of polymers; Preparation
• ISSN: 0022-2348; 1525-609X
• DOI: 10.1080/00222348.2014.901872

A vibrating sample magnetometer (VSM) has been used to study the field-dependent magnetization, M(H), of the d 5 −d 7 metal acetates [M(OAc) 2 .nH 2 O], metal β−diketonate complexes [M(tba) 2 (H 2 O) 2 ] and the macromolecular polymers [M(tba) 2 (4,4-bipy)] n (where, M = Mn(II), Fe(II), and Co(II), OAc = O 2 CCH 3 , tba = deprotonated 3-benzoyl-1.1.1-trifluoroacetone, and 4,4-bipy = 4,4′-bipyridine). The magnetic field strength (H) was applied in the range of 0−10 4 O e at ambient temperature (ca. 23°C). The experimental results showed that the d 5 −d 7 metal acetate, complexes and polymers exhibit low paramagnetic properties excepting [Fe(tba) 2 (4,4-bipy)] n polymer, which had negative magnetization M(emu/g) showing diamagnetic properties in the range 0−10 4 O e . The magnetization was almost equal to zero without an applied magnetic field (H(O e )) for each d 5 −d 7 metal acetate, complex, and polymer. The linear M(H) curve had a magnetic saturation for iron and manganese acetate species at the magnetic field strengths of 3.1 × 10 3 and 4.7 × 10 3 Oe, respectively. The external magnetic field reached 9.0 × 10 3 O e without any saturation magnetization for the cobalt compounds. The coordination effect of 3-benzoyl-1.1.1-trifluoroacetone (H-tba) and 4,4′-bipyridine (4,4′-bipy) ligands on the field-dependent magnetization M(H) and paramagnetic behavior of d 5 −d 7 metal atoms is discussed. The field-dependent magnetization M(H) curves of metal β−diketonate complexes and the polymers including d 5 −d 7 metal acetates showed a weak field octahedral geometry.