CP/MAS NMR studies on binding environment of CH ₃ CN in Cu( <scp>i</scp> ) complexes with disilane-bridged bis(methylpyridine) ligands

CP/MAS NMR spectroscopies have developed as an important tool for studying the structure in the crystalline state. In this work, the structures of representative Cu(i) complexes 1-3 with disilane-bridged bis(methylpyridine) ligands in the crystalline state were investigated by CP/MAS NMR. ¹³C CP/MAS NMR confirmed the presence of CH₃CN in the crystals of 2 and 3, but the environment around CH₃CN could not be determined. Natural abundance (<i>ca.</i> 0.36%) ¹⁵N CP/MAS NMR measurements could confirm the difference of CH₃CN environment between coordinating solvent in 2 and crystal solvent in 3. The ¹⁵N CP/MAS of CH₃CN in 3 shows a singlet because it is not coordinated to Cu(i) and the crystal structure is stabilized by multiple intermolecular interactions. These data have provided valuable information on Cu(i) coordination environment, which was in good accordance with single-crystal X-ray analysis.