Hepta‐Coordinated Mono‐ and Diorganotin(IV) Compounds with N3O2 Chelating Hydrazone Ligand

A series of organotin(IV) complexes featuring the pro‐ligand 2,6‐diacetylpyridine bis(2‐methylbenzoylhydrazone) (H 2 L Me ) and various axial ligands have been synthesized. The reactions of H 2 L Me with R 2 SnO (where R = Me, n ‐Bu, n ‐Oct, or t ‐Bu) and n‐ BuSnCl 3 in anhydrous toluene yielded the seven‐coordinate complexes [Me 2 Sn(L Me )] ( 1 ), [ n ‐Bu 2 Sn(L Me )] ( 2 ), [ n ‐Oct 2 Sn(L Me )] ( 3 ), [ t ‐Bu 2 Sn(L Me )] ( 4 ), and [ n ‐BuSn(L Me )Cl] ( 5 ), respectively. Subsequent treatment of complex 5 with NaN 3 and NH 4 SCN afforded the corresponding isothiocyanate and azide derivatives, [ n ‐BuSn(L Me )N 3 ] ( 6 ), and [ n ‐BuSn(L Me )NCS] ( 7 ), respectively. Single crystal X‐ray diffraction studies confirmed that the tin centers in complexes 1 , 2 , 4 , 6 , and 7 adopt a seven‐coordinate geometry with a pentagonal bipyramidal configuration. The κ‐ N 3 O 2 donor set of the ligand occupies the equatorial plane, while the axial positions are occupied by either two R groups, or one R group and one Cl, N 3 , or NCS ligand, depending on the specific complex. In addition to X‐ray diffraction analysis, all complexes 1 − 7 are characterized using Fourier transform infrared spectroscopy, high‐resolution mass spectrometry , and solution‐state Fourier transform nuclear magnetic resonance spectroscopy. The structural distortion within the SnN 3 O 2 equatorial plane, attributed to positional shifts of the Sn(IV) center, are also discussed.