High Nuclearity Antimonato‐Polyoxovanadate Cluster {V 15 Sb 6 O 42 } as a Synthon for the Solvothermal in situ Generation of α‐ and β‐{V 14 Sb 8 O 42 } Isomers

New heteroatom polyoxovanadates (POVs) were synthesized by applying a water‐soluble high‐nuclearity cluster as new synthon. The [V 15 Sb 6 O 42 ] 6− cluster shell exhibiting D 3 symmetry was in situ transformed into completely different cluster shells, namely, the α‐[V 14 Sb 8 O 42 ] 4− isomer with D 2 d and the β‐[V 14 Sb 8 O 42 ] 4− isomer with D 2 h symmetry. The solvothermal reaction of {Ni(en) 3 } 3 [V 15 Sb 6 O 42 (H 2 O) x ] ⋅ 15 H 2 O ( x =0 or 1; en=ethylenediamine) in water led to the crystallization of [{Ni(en) 2 } 2 V 14 Sb 8 O 42 ] ⋅ 5.5 H 2 O containing the β‐isomer. The addition of [Ni(phen) 3 ](ClO 4 ) 2 ⋅ 0.5 H 2 O (phen=1,10‐phenanthroline) to the reaction slurry gave the new compound {Ni(phen) 3 } 2 [V 14 Sb 8 O 42 ] ⋅ phen ⋅ 12 H 2 O with the α‐isomer. Both transformation reactions are complex due the change of symmetry, the chemical composition, and rearrangement of the VO 5 square pyramids and Sb 2 O 5 handle‐like moieties.