Dodecanuclear water cluster in bowl: microwave-assisted synthesis of a heptanuclear cobalt(II) cluster

• Published in: Journal of coordination chemistry 2014-10, Vol.67 (19), p.3155-3166
• Main Authors: Zhang, Shu-Hua, Huang, Qiu Ping, Zhang, Hai Yang, Li, Gui, Liu, Zheng, Li, Yan, Liang, Hong
• Format: Article
• Language: English
• Subjects: Acetonitrile; Clusters; Dodecanuclear water cluster; Exchange; Ferromagnetism; Heptanuclear cluster; Hydrogen bonds; Ion exchangers; Magnetic exchange; Solvents; Stands
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2014.964221

A heptanuclear double-bowl-like cluster [Co 7 (mmp) 6 (OH) 6 ] 2 ·(ClO 4 ) 2 ·12H 2 O (1·12H 2 O, Hmmp is 2-methoxy-6-methyliminomethyl-phenol) has been synthesized through the microwave-assisted reaction of Co(ClO 4 ) 2 ·6H 2 O with 2-hydroxy-3-methoxy-benzaldehyde (Hhmb) and methylamine in mixed solvent (acetonitrile : distilled water = 9 : 1) for 29 min. 1·12H 2 O was heated until 180 °C and it formed a non-water complex [Co 7 (mmp) 6 (OH) 6 ] 2 ·(ClO 4 ) 2 (1). The core of 1·12H 2 O can be described as a double bowl, while the dodecanuclear water cluster stands on the bowl. Magnetic investigations show that 1·12H 2 O and 1 display ferromagnetic interaction between cobalt ions. Moreover, 1 shows single molecular magnet behavior under 2 K. Magnetic studies indicate that hydrogen bond plays a vital role in transferring magnetic exchange effects. Using microwave assisted heating solvothermal method, a double-bowl-like heptanuclear cluster [Co 7 (mmp) 6 (OH) 6 ] 2 ·(ClO 4 ) 2 ·12H 2 O (1·12H 2 O) has been synthesized. We study the thermolysis of 1·12H 2 O through TG and XRD. 1 was formed through heating 1·12H 2 O. Magnetic behavior between 1 and 1·12H 2 O indicates hydrogen bonds playing an important role for transferring magnetic exchange effects. 1 shows a single molecular magnet behavior under 2 K.