Bis[acetylacetonato(1—)‐ O , O ]di(cyanato‐ N )silicon(IV): A Neutral Hexacoordinate Silicon Complex with Two Cyanato‐ N Ligands

The neutral hexacoordinate silicon(IV) complex cis ‐[(acac) 2 Si(NCO) 2 ] ( cis ‐ 8 ; acac = acetylacetonato‐ O , O ) was synthesized, starting from Si(NCO) 4 . Compound cis ‐ 8 was structurally characterized in the solid state ( 13 C, 15 N, and 29 Si MAS NMR; crystal structure analysis) and in solution ( 1 H, 13 C, and 29 Si NMR). The experimental investigations were complemented by computational studies (RI‐MP2 geometry optimizations of cis ‐ 8 and trans ‐ 8 and of the corresponding cyanato‐ O isomers cis ‐[(acac) 2 Si (OCN) 2 ] ( cis ‐ 9 ) and trans ‐[(acac) 2 Si(OCN) 2 ] ( trans ‐ 9 ); calculations of the 29 Si NMR chemical shifts of cis ‐ 8 , trans ‐ 8 , cis ‐ 9 and trans ‐ 9 using the optimized structures).