Über Metallalkyl‐ und ‐arylverbindungen, 48 Monomeres, tetrameres und polymeres Natriumfluorenid S [S = Me₂N(CH₂)₂N(Me)(CH₂)₂NMe₂, Me₂N(CH₂)_<i>n</i>NMe₂ (<i>n</i> = 2, 3)]

Abstract

Monomeric, Tetrameric, and Polymeric Sodium Fluorenide · S [S = Me 2 N(CH 2 ) 2 N(Me)(CH 2 ) 2 NMe 2 , Me 2 N(CH 2 ) n NMe 2 (n = 2, 3)] The metallation of fluorene with sodium butanide (NanBu) in the presence of N bases yields solvated sodium fluorenide. Base adducts with bi‐ and tridentate N ‐chelating ligands have been isolated: Na(fluorenide)(pmdta) ( 1 [PMDTA = Me 2 N(CH 2 ) 2 N(Me)(CH 2 ) 2 NMe 2 ], [Na(fluorenide)(tmeda)] n ( 2 ) [TMEDA = Me 2 N(CH 2 ) 2 N(Me)(CH 2 ) 2 NMe 2 ], [Na(fluorenide)(tmeda)] 4 ) ( 3 ) [TMPDA = Me 2 N(CH 2 ) 3 NMe 2 ]. According to X‐ray diffraction studies monomeric ( 1 ), polymeric ( 2 ), and cyclic‐tetrameric ( 3 ) structures are present in the crystal. These pronounced structural variations are explained on the basis of ionic contact aggregates where together with coulomb interactions the steric requirements of the ligands become rather important. Contact distances between Na ions and several C atoms of the carbanion may vary (ca. 260—300 pm) and definite coordination numbers become meaningless.