Synthesis and photochemical and magnetic properties of Cr, Mn, Fe, and Co complexes based on the 1-{(1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indolin]-8-yl)methyl}pyridinium cation

• Published in: Russian chemical bulletin 2008-07, Vol.57 (7), p.1451-1460
• Main Authors: Sanina, N. A., Aldoshin, S. M., Shilov, G. V., Kurganova, E. V., Yurieva, E. A., Voloshin, N. A., Minkin, V. I., Nadtochenko, V. A., Morgunov, R. B.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Full Articles; Inorganic Chemistry; Organic Chemistry
• ISSN: 1066-5285; 1573-9171
• DOI: 10.1007/s11172-008-0188-3

Paramagnetic (tris)oxalates with the composition (SP) 3 M(C 2 O 4 ) 3 ·4H 2 O (M = Cr ( 2 ), Mn ( 3 ), Fe ( 4 ), and Co ( 5 )) were synthesized for the first time based on the spiropyran salt SP + Br − ( 1 ) with the SP + cation containing the pyridine ring in the aliphatic chain of the benzopyran moiety, which was also prepared in the present study. According to X-ray diffraction data, the SP + cations in the starting salt 1 are close-packed thus hindering photochromic transformations. The spin for paramagnet 4 is 5/2, which corresponds to the Fe III atom in the high-spin state, the spin of the system remaining unchanged under UV irradiation. In complex 3 , a crossover from ferromagnetic to antiferromagnetic correlations was observed after the replacement of the inorganic cation with the organic spiropyran cation.