Analysis of the Photomagnetic Properties of Cyano-Bridged Heterobimetallic Complexes by X-Ray Diffraction
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- 作者：Helle Svendsen ; Mads Ry Vogel J酶rgensen ; Jacob Overgaard ; Yu-Sheng Chen ; Guillaume Chastanet ; Jean-Fran莽ois L茅tard ; Kenichi Kato ; Masaki Takata ; Bo B. Iversen
- 刊名：Inorganic Chemistry
- 出版年：2011
- 出版时间：November 7, 2011
- 年：2011
- 卷：50
- 期：21
- 页码：10974-10984
- 全文大小：1155K
- 年卷期：v.50,no.21(November 7, 2011)
- ISSN：1520-510X
文摘
Single crystal synchrotron X-ray diffraction measurements have been carried out on [Nd(DMF)4(H2O)3(渭-CN)Fe(CN)5]路H2O (DMF = dimethyl-formamide), 1; [Y(DMF)4(H2O)3(渭-CN)Fe(CN)5]路H2O, 2; [Ce(DMF)4(H2O)3(渭-CN)Fe(CN)5]路H2O, 3; [Sm(DMF)4(H2O)3(渭-CN)Fe(CN)5]路H2O, 4; [Tb(DMF)4(H2O)3(渭-CN)Fe(CN)5]路H2O, 5; [Yb(DMF)4(H2O)3(渭-CN)Fe(CN)5]路H2O, 6; and [Nd(DMF)4(H2O)3(渭-CN)Co(CN)5]路H2O, 7, at 15(2) K with and without UV illumination of the crystals. Significant changes in unit cell parameters are observed for all of the iron-containing complexes, while compound 7 shows no response to UV illumination. These results are consistent with previous results and are furthermore reproduced by powder synchrotron X-ray diffraction for compounds 1 and 7. Photoexcited crystal structures have been determined for 1鈥?b>6 from refinements of two-conformer models, and excited state occupancies in the range 80鈥?4% are found. Significant bond length changes are observed for the Fe鈥搇igand bonds (up to 0.06 脜), the cyano bonds (up to 0.02 脜), and the lanthanide鈥搇igand bonds (up to 0.1 脜). On the contrary, powder X-ray diffraction on the simple compound K3Fe(CN)6, 8, upon UV illumination does not show any structural changes, suggesting that the photomagnetic effect requires the presence of both the transition metal and the lanthanide ion. Photomagnetic measurements show an increase in magnetization of the excited state of 1 of up to 3%, which is much diminished compared with previously published values of 45%. Furthermore, they show that the isostructural complex [La(DMF)4(H2O)3(渭-CN)Fe(CN)5]路H2O, 9, exhibits identical magnetic responses in the UV-induced excited crystal structure.