Self‐Assembly of an Alkali Metal Cluster Stabilized by a New Flexidentate Metalloligand: Formation and Structure of Heterobimetallic Na–Mo and Cs–Mo 2D Networks

A new tridentate ligand, {(3,5‐di‐ tert ‐butyl‐2‐hydroxybenzyl)amino}acetic acid, has been synthesized. This ligand forms [{Na 4 (H 2 O) 4 (μ‐H 2 O) 2 }(Mo 2 O 5 L 2 ) 2 ] ( 1 ), which contains an Na 4 4+ cluster cation stabilized by [LMoO 2 (μ‐O)MoO 2 L] 2– , upon reaction with Na 2 MoO 4 in aqueous methanol. This compound has been characterized by various spectroscopic techniques and crystallizes in the triclinic space group P $\bar {1}$ . Furthermore, compound 1 undergoes smooth exchange of Na + for Cs + to give [Cs 2 (Mo 2 O 5 L 2 ) · H 2 O] n ( 2 ) upon treatment with CsCl in aqueous methanol. Similarly, 2 reacts with an excess of NaCl to produce 1 . Complex 2 crystallizes in the monoclinic space group C 2/ c . The crystal structure of this compound reveals that the geometry of the [LMoO 2 (μ‐O)MoO 2 L] 2– unit stays almost intact but that it stabilizes a polymeric chain of Cs + cations, unlike in 1 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)