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RESEARCH PRODUCT

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

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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.