SHG-active NIR-emissive molecular nanomagnets generated in layered neodymium()-octacyanidometallate() frameworks

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 9; no. 33; pp. 175 - 1717
• Main Authors: Jankowski, Robert, Zakrzewski, Jakub J, Zychowicz, Mikolaj, Wang, Junhao, Oki, Yurie, Ohkoshi, Shin-ichi, Chorazy, Szymon, Sieklucka, Barbara
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 26.08.2021
• Subjects: Absorption spectra; Alternating current; Anisotropy; Coordination polymers; Crystallography; Electron transitions; Emission spectra; Emissivity; Infrared spectroscopy; Magnetic measurement; Magnetic properties; Magnets; Mathematical analysis; Near infrared radiation; Neodymium; Optical properties; Photoluminescence; Second harmonic generation; Transition metals
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d1tc00825k

Lanthanide( iii ) single-molecule magnets (Ln-SMMs) offer the fruitful conjunction of magnetic and photoluminescent properties originating from their single-ion anisotropy and emissive f-f electronic transitions. The flexibility of lanthanide( iii )-based coordination systems is the most significant prerequisite for the generation of additional physical phenomena, including non-linear optical effects related to the lack of inversion centre. In the quest towards multifunctional molecular nanomagnets, we report heterometallic d-f layered coordination polymers, {[Nd III 4 (H 2 O) 17 (pzdo) 5 ][M IV (CN) 8 ] 3 }·9H 2 O (M = Mo ( 1 ), W ( 2 ); pzdo = pyrazine- N , N ′-dioxide). They crystallize in the non-centrosymmetric C 2 space group due to the spontaneous resolution process, confirmed by the observation of second harmonic generation (SHG) activity. These materials exhibit UV-to-vis-light-induced near-infrared (NIR) Nd III -centred luminescence sensitized by octacyanidometallates and organic ligand, and slow relaxation of magnetization of Nd III complexes which was investigated by alternate-current (ac) magnetic measurements and the ab initio calculations. The observed magnetic and optical properties are sensitive to the nature of the d-transition metal centre, namely most of their features are improved upon the replacement of Mo IV with W IV centres. In this work, we show the generation of SHG-active NIR-emissive SMMs realized by Nd 3+ ions inserted into hybrid layers built of inorganic [M(CN) 8 ] 4− and organic pzdo linkers. Nd 3+ ions incorporated into hybrid layers built of [M(CN) 8 ] 4− (M = Mo IV or W IV ) and pyrazine N , N ′-dioxide linkers form enantiomorphic materials exhibiting tunable NIR luminescence, SHG activity, and slow magnetic relaxation.