Magneto-structural correlations are of great importance in developing single-molecule magnets(SMMs)for storage and quantum processing of information.In this work,three cyclooctatetraenylido(COT)ligands,namely COT^(TMS...Magneto-structural correlations are of great importance in developing single-molecule magnets(SMMs)for storage and quantum processing of information.In this work,three cyclooctatetraenylido(COT)ligands,namely COT^(TMS1),COT^(TMS2),and COT^(TMS3) equipped with one,two,and three trimethylsilyl(TMS)substituent(s),respectively,were used to prepare the corresponding Er(Ⅲ)complexes,namely[K(DME)_(2)][Er(COT^(TMS1))_(2)](1:DME,1,2-dimethoxyethane),[K(DME)_(2)][Er(COT^(TMS2))_(2)](2),and[K(18-crown-6)_(1.5)][Er(COT^(TMS3))_(2)](3).The complexes,each featuring an Er(Ⅲ)ion sandwiched by two cyclooctatetraenyl rings,possess uni-axial magnetic anisotropy and display single-molecule magnet behaviors with energy barriers of 208(1)K for 1,193(2)K for 2,and 217(18)K for 3,and blocking temperatures of 11,10,and 9 K,respectively.The relaxation times are found to be closely related to the number of TMS substituents,with that of 1 being about 10 times longer than that of 2,and more significantly,100 times longer than that of 3 at the same temperatures.Studies using infrared spectroscopy indicate that the molecular vibrations of the complexes intensify upon increasing the number of TMS substituents in the ligands,resulting in faster magnetic relaxation.Further analyses reveal that the molecular vibrations in these complexes are related to the pre-exponential factor τ_(0) for the Orbach process or C value for the Raman process.展开更多
基金supported by the National Natural Science Foundation of China(92261203,22101116 and 21971106)the Science Research Foundation of Jilin Province(YDZJ202301ZYTS478)+1 种基金Shenzhen Fundamental Research Program(JCYJ20220530115001002)the Stable Support Plan Program of Shenzhen Natural Science Fund(20200925161141006).
文摘Magneto-structural correlations are of great importance in developing single-molecule magnets(SMMs)for storage and quantum processing of information.In this work,three cyclooctatetraenylido(COT)ligands,namely COT^(TMS1),COT^(TMS2),and COT^(TMS3) equipped with one,two,and three trimethylsilyl(TMS)substituent(s),respectively,were used to prepare the corresponding Er(Ⅲ)complexes,namely[K(DME)_(2)][Er(COT^(TMS1))_(2)](1:DME,1,2-dimethoxyethane),[K(DME)_(2)][Er(COT^(TMS2))_(2)](2),and[K(18-crown-6)_(1.5)][Er(COT^(TMS3))_(2)](3).The complexes,each featuring an Er(Ⅲ)ion sandwiched by two cyclooctatetraenyl rings,possess uni-axial magnetic anisotropy and display single-molecule magnet behaviors with energy barriers of 208(1)K for 1,193(2)K for 2,and 217(18)K for 3,and blocking temperatures of 11,10,and 9 K,respectively.The relaxation times are found to be closely related to the number of TMS substituents,with that of 1 being about 10 times longer than that of 2,and more significantly,100 times longer than that of 3 at the same temperatures.Studies using infrared spectroscopy indicate that the molecular vibrations of the complexes intensify upon increasing the number of TMS substituents in the ligands,resulting in faster magnetic relaxation.Further analyses reveal that the molecular vibrations in these complexes are related to the pre-exponential factor τ_(0) for the Orbach process or C value for the Raman process.
