pH‐Controlled Assemblies of Dimethyltin‐Functionalized 9‐Tungstophosphates with Guanidinium as Structure‐Directing Cation

Abstract Aqueous reaction of (CH 3 ) 2 SnCl 2 with Na 9 [ A ‐α‐PW 9 O 34 ] in a 3:1 ratio with [C(NH 2 ) 3 ] + as structure‐directing agent resulted in three distinct assemblies of dimethyltin‐functionalized tungstophosphates depending on the pH: [{(CH 3 ) 2 Sn(H 2 O)}{(CH 3 ) 2 Sn}( A ‐α‐PW 9 O 34 )] 5– ( 1 ) at pH = 4.5; [{(CH 3 ) 2 Sn(H 2 O) 2 }{(CH 3 ) 2 Sn(H 2 O)} 2 ( A ‐α‐PW 9 O 34 )] 3– ( 2 ) at pH = 3.0; and [{(CH 3 ) 2 Sn(H 2 O)} 3 ( A‐ α‐PW 9 O 34 )] 3– ( 3 ) at pH = 2.0. All three compounds have been characterized in the solid‐state by elemental and thermal analyses, infrared spectroscopy and single‐crystal X‐ray diffraction. The [ A ‐α‐PW 9 O 34 ] 9– trilacunary fragments have three {(CH 3 ) 2 Sn} 2+ groups anchored on the vacant sites via two Sn–O(W) bonds each and they are linked into guanidinium‐templated, extended architectures with dimensionalities increasing with the acidity of the reaction media. The structure of 1 consists of a 1‐dimensional arrangement of alternating [ A ‐α‐PW 9 O 34 ] 9– subunits and trans ‐(CH 3 ) 2 SnO 4 bridging moieties, whereas compounds 2 and 3 are 2‐ and 3‐dimensional assemblies, respectively, of monomeric [{(CH 3 ) 2 Sn} 3 ( A ‐α‐PW 9 O 34 )] 3– building blocks connected via weak intermolecular Sn–O=W bridges.