Synthesis and characterization of an unprecedented water-soluble tris-functionalized Anderson-type polyoxometalate.

A water-soluble single-sided tris-functionalized Anderson-type polyoxometalate (POM) with counter ammonium cations, (NH 4) 2 {[NH 3 C(CH 2 O) 3 Cr(OH) 3 Mo 6 O 18 }·5H 2 O(1), has been synthesized by a hydrothermal reaction of parent Anderson-type POMs, [NH 4 3 [Cr(OH) 6 Mo 6 O 18 (CrMo6) and tris ligand (HOCH 2) 3 CNH 2 ·HCl (Tris) in aqueous solution. Single-crystal X-ray diffraction analysis has revealed that compound 1 crystallizes in triclinic space group P-1. Each asymmetric unit contains one protonated single-side tris-functionalized Anderson-type POMs anion cluster, {[NH 3 C(CH 2 O) 3 Cr(OH) 3 Mo 6 O 18 }2- (CrMo6-tris-NH3), and two NH 4 + counter cations and five crystallized H 2 O solvent molecules, which can assemble into a layer-by-layer structure via hydrogen bonding interactions. Furthermore, compound 1 was characterized by elemental analysis, FT-IR, 1H NMR, UV–Vis and TGA. Such a water-soluble tris-functionalized POM with the remote amino reactive group has not been reported before and it may serve as a valuable synthon for further post-functionalization in aqueous solution. This work reported an unprecedented water-soluble single-sided tris-functionalized Anderson-type polyoxometalates (POMs) with counter ammonium cations. Image 1 • A water-soluble tris-functionalized Anderson polyoxometalate has been synthesized. • The polyoxometalate form a supramolecular structure via H-bonding interactions. • This polyoxometalate is a valuable synthon for aqueous post-functionalization. [ABSTRACT FROM AUTHOR]