Controlled Assembly of [Nb6‐xWxO19](8‐x)‐ (x = 0‐4) Lindqvist Ions with (Amine)copper Complexes.

The mixed addenda isopolyanion, [N(CH 3 ) 4 ] 2 Na 2 [cis-Nb 2 W 4 O 19 ]·18H 2 O, reacts with Cu(NO 3 ) 2 in water and in the presence of NH 2 CH 2 CH 2 NH 2 (en) or NH 4 OH at 60 °C to yield a phase that is decorated {[Cu(en) 2 (H 2 O)] 2 -[Nb 2 W 4 O 19 ]·2H 2 O (1)) or charge-balanced {[Cu(NH 3 ) 4 -(H20)] 2 [Nb 2 W 4 O 19 ]·8H 2 O (2)), respectively, by (amine)copper complexes. The prolonged heating at 95 °C of [N(CH 3 ) 4 ] 6 -[Nb 10 O 28 ]·6H 2 O, [N(CH3)4] 2 Na 2 [cis-Nb 2 W 4 O 19 ]·18H 2 O, or Na4K2[cis-Nb 4 W 2 O 19 ]·12H 2 O and Cu(NO 3 ) 2 in a mixed water/amine [en or NH 2 CH 2 CH 2 CH 2 NH 2 (dap)] solution results in the formation of two-dimensional materials with alternate layers of (amine)copper complexes linking Lindqvist [Nb 6-x W x O 19 ] (8-x)- (x = 0-4) clusters. These phases include: [Cu(dap) 2 ] 3 [Nb 4 W 2 O 19 ]·7H 2 O (3), [Cu(dap) 2 ] 3 -[H 2 Nb 6 O 19 ]·6H 2 O (4), [Cu(dap) 2 ] 3 [Nb 3 W 3 O 19 ]-Cl·6H 2 O (5), and [Cu(en) 2 ] 3 [Nb 4 W 2 O 19 ]·6H 2 O (6). Complexes 4 and 5 result from the decomposition of [Nb 10 O 28 ] 6- and [cis-Nb 2 W 4 O 19 ] 4- to [H 2 Nb 6 O 19 ] 6- and [fac-Nb 3 W 3 O 19 ] 5- , respectively, in alkaline solution. Complex 5 contains an extra-framework site that is occupied by Cl - , but this site is occupied by a water molecule in 3 and is vacant in structures 4 and 6. The results of this study suggest that charge density, cluster charge and symmetry, and cluster-cation pairing are all important parameters in the incorporation of d-electron metals onto the surfaces of [Nb 6-x W x O 19 ] (8-x)- (x = 0-4) clusters or into the frameworks of Lindqvist-based complex materials.