title: Photoinduced spin transition for Iron(II) compounds with liquid-crystal properties.
abstract: The iron(II) compounds [Fe(3Cn-L)2(NCS)2] (n = 6 (1), n = 8 (2), n = 10 (3), n = 12 (4), n = 14 (5), n = 16 (6), n = 18 (7), n = 20 (8), and n = 22 (9)) were synthesized and their physical properties characterized by polarizing optical microscopy, differential scanning calorimetry, and powder X-ray analysis, where 3Cn-L denotes bidentate Schiff-base ligands formed from the corresponding aniline derivatives and pyridine-2-carboxyaldehyde. The iron(II) compounds 4-8 exhibited crystal to liquid-crystal transitions at 318, 334, 345, 338, and 347 K, respectively. Variable-temperature magnetic susceptibility measurements revealed that the compounds 1-9 exhibit spin-crossover behavior between the high-spin and low-spin states and a photoinduced spin transition from a low-spin state to a metastable high-spin state. Therefore, the iron(II) compounds 4-8 can undergo spin-crossover and photoinduced spin transition as well as have liquid-crystal properties all in a single molecule. Compounds with multifunctions are important in the development of molecular switches and optical materials.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. hayascc@mbox.nc.kyushu-u.ac.jp
authors.forename: Shinya
authors.initials: S
authors.lastname: Hayami
authors.forename: Natsuko
authors.initials: N
authors.lastname: Motokawa
authors.forename: Aya
authors.initials: A
authors.lastname: Shuto
authors.forename: Naoji
authors.initials: N
authors.lastname: Masuhara
authors.forename: Takehiro
authors.initials: T
authors.lastname: Someya
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ogawa
authors.forename: Katsuya
authors.initials: K
authors.lastname: Inoue
authors.forename: Yonezo
authors.initials: Y
authors.lastname: Maeda
mesh_terms: D018360:Crystallography, X-Ray; D005296:Ferrous Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D050866:Liquid Crystals / Q000737:chemistry* / Q000528:radiation effects; D008958:Models, Molecular; D015394:Molecular Structure; D010777:Photochemistry; D011789:Quantum Theory; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D005296:Ferrous Compounds