Synthesis, Characterization and Properties of Two Novel Complexes Based on 2‐Aminopyridine and Polyoxometalates †

Two novel complexes based on 2‐aminopyridine and polyoxometalates (POMs) formulated as (C 5 H 7 N 2 ) 6 ‐[PMo 11 V Mo VI O 40 (V IV O) 4 ]·H 2 O ( 1 ) and (C 5 H 7 N 2 ) 16 [P 2 W 18 O 61.5 ] 2 ( 2 ) were hydrothermally synthesized and structurally characterized by elemental analysis, ICP, IR, UV‐Vis, TG, ESR and single crystal X‐ray diffraction methods. Complex 1 consists of a novel tetra‐capped Keggin POMs, [PMo 11 V Mo VI O 40 (V IV O) 4 ] 6− in which four [V IV O 5 ] square pyramids cap the equatorial positions of Keggin core [PMo 11 V Mo VI O 40 ] 14− , linked together with six protonated 2‐aminopyridine via hydrogen bonding interactions. Dawson and lacunary Dawson POMs, [P 2 W 18 O 62 ] 6− and [P 2 W 17 O 61 ] 10− coexist in complex 2 , they link together with sixteen protonated 2‐aminopyridine via hydrogen bonding interactions. Complex 2 exhibits photochromic property.