화학공학소재연구정보센터
Inorganic Chemistry, Vol.47, No.23, 11245-11256, 2008
Investigation of Silver-Containing Layered Materials and Their Interactions with Primary Amines Using Solid-State Ag-109 and N-15 NMR Spectroscopy and First Principles Calculations
Silver-containing layered networks of the form [Ag(L)] (L = 4-pyridinesulfonate or p-toluenesulfonate) were treated with primary amines in different ratios. The structures of the parent supramolecular networks are well-known; however, their interactions with primary amines lead to the formation of new layered materials for which single-crystal X-ray structures cannot be obtained. Solid-state Ag-109, N-15, and C-13 cross-polarization magic-angle spinning (CP/MAS) NMR experiments, in combination with powder X-ray diffraction experiments and ab initio calculations, are utilized to investigate the interactions between the primary amines and the parent materials, and to propose structural models for the new materials. Ag-109 chemical shift (CS) tensor parameters are extremely sensitive to changes in silver environments; hence, H-1-Ag-109 CP/MAS NMR experiments are used to distinguish and characterize silver sites. The combination of Ag-109 and N-15 NMR experiments on starting materials and samples prepared with both N-15-labeled and unlabeled amines permits the accurate measurements of indirect (1)J(Ag-109,N-15) and (1)J(Ag-109, N-14) spin-spin coupling constants, providing further information on structure and bonding in these systems. First principles calculations of silver CS tensors and (1)J(Ag-109, N-14) coupling constants in model complexes aid in formulating the proposed structural models for the new materials, which are largely comprised of layers of silver-diamine cations.