Gradual or Hysteretic Transition: Anion Effects on Cobalt(II) Spin Crossover Complexes
Yu-Chen Sun
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorYing-Lian Li
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorCheng-Cheng Zhang
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorFeng-Li Chen
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorDong Shao
Hubei Key Laboratory of Processing and Application of Catalytic Materials, College of Chemistry and Chemical Engineering, Huanggang Normal University, Huanggang, Hubei, 438000 China
Search for more papers by this authorYue Zhao
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorHai-Yan Wei
Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorCorresponding Author
Xin-Yi Wang
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
E-mail: [email protected]Search for more papers by this authorYu-Chen Sun
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorYing-Lian Li
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorCheng-Cheng Zhang
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorFeng-Li Chen
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorDong Shao
Hubei Key Laboratory of Processing and Application of Catalytic Materials, College of Chemistry and Chemical Engineering, Huanggang Normal University, Huanggang, Hubei, 438000 China
Search for more papers by this authorYue Zhao
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorHai-Yan Wei
Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, Jiangsu, 210023 China
Search for more papers by this authorCorresponding Author
Xin-Yi Wang
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210023 China
E-mail: [email protected]Search for more papers by this authorComprehensive Summary
To better understand the impact of different anions on the structures and SCO properties of the CoII SCO complexes, six new complexes [Co(terpy-CH2OH)2]A2·sol (terpy-CH2OH = 4′-(hydroxymethyl)-2,2′;6′,2″-terpyridine, A = Br– (1, sol = 1.5H2O), I– (2), N3– (3, sol = 2H2O), H3BCN– (4), OTf– (5), and TsO– (6, sol = 4H2O·CH3CN), have been synthesized and characterized. All six compounds consist of mononuclear [Co(terpy-CH2OH)2]2+ cations and charge-balancing anions that differ in size, shape, and hydrogen bonding capacity. Complexes 1, 2, 3, and 6 displayed incomplete gradual SCO transitions, whereas 4 and 5 exhibited abrupt hysteretic spin transitions with loops of 12 and 16 K (250.0—262.0 K for 4, and 370.0—386.0 K for 5, respectively), closely resembling our previously reported complexes with SCN– and SeCN– anions. The occurrence of the order-disorder transition of the CH2OH groups and their transition temperatures are determined by the size and hydrogen bonding capability of the anions. Remarkably, the transition temperatures of complexes with H3BCN–, SCN–, OTf–, and SeCN– anions exhibit an upward trend as the size and mass of the anions increase, as confirmed through detailed single crystal structure analyses conducted in both high-spin and low-spin states for all four complexes.
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