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

A heptanuclear double-bowl-like cluster [Co-7(mmp)(6)(OH)(6)](2)center dot(ClO4)(2)center dot 12H(2)O (1 center dot 12H(2)O, Hmmp is 2-methoxy-6-methyliminomethyl-phenol) has been synthesized through the microwave-assisted reaction of Co(ClO4)(2)center dot 6H(2)O with 2-hydroxy-3-methoxy-benzaldehyde (Hhmb) and methylamine in mixed solvent (acetonitrile : distilled water=9:1) for 29min. 1 center dot 12H(2)O was heated until 180 degrees C and it formed a non-water complex [Co-7(mmp)(6)(OH)(6)](2)center dot(ClO4)(2) (1). The core of 1 center dot 12H(2)O can be described as a double bowl, while the dodecanuclear water cluster stands on the bowl. Magnetic investigations show that 1 center dot 12H(2)O and 1 display ferromagnetic interaction between cobalt ions. Moreover, 1 shows single molecular magnet behavior under 2K. Magnetic studies indicate that hydrogen bond plays a vital role in transferring magnetic exchange effects.