Study of novel mesostructured materials based on tin(IV) sulfide .2. Transformation between two lamellar phases

A new lamellar mesophase named C(16)TMA-SnS-L1 was obtained at room temperature in the system C(16)TMABr-SnCl4Na2S-H2O when the pH of the reactant mixture was 12.0. The transformation of C(16)TMA-SnS-L1 into C(16)TMA-SnS-L was observed with the increase of the crystallization time. These two phases were characterized by XRD, SEM, Ar-DTA, TG, Sn-119 CPMAS NMR, C-13 CPMAS NMR, EDX and bulk chemical analysis. Although the coordination of tin(IV) is tetrahedral in both phases, different environments of tin(IV) are present. The Sn-119 shielding tensor of C(16)TMA-SnS-L is axially symmetric, whereas that of C(16)TMA-SnS-L1 is asymmetric. A different geometry of the aliphatic chains of CH3(CH2)(15)N+(CH3)(3) in both phases was found by C-13 CPMAS NMR.