Strukturen von polaren Bariumorganylen: Synthese und Struktur von Ether‐, Pyridin‐ und Kronenether‐Addukten des Bis(fluorenyl)bariums

The synthesis and structure of six bis(fluorenyl)barium complexes is reported. Bis(fluorenyl)barium ( 1 ) was synthesized from barium bis(hexamethyldisilazide) and fluorene. Tetrahydrofuran, dimethoxyethane, and pyridine containing complexes ( 1a , 1b , 2 , and 3a ) could be synthesized by crystallizing 1 from THF, DME, or pyridine. The X‐ray structures of all crystalline compounds reveal a bent‐sandwich structure with Ba–C distances between 303.3 and 322.2 pm to the five‐membered rings of the fluorenyl ligands and a ring centroid–Ba distance of 288.2 to 289.0 pm. The ring centroid–Ba–ring centroid angles are 134.8 to 137.0°. Three THF ( 1a , 1b ), two DME ( 2 ), or three pyridine molecules ( 3a ) complete the coordination sphere of the barium atom. Two crown ether complexes ( 4a and 5a ) of bis(fluorenyl)barium were synthesized by reacting 1 with the crown ethers 18‐crown‐6 and dibenzo‐18‐crown‐6. From pyridine as solvent the following two compounds could be obtained in single crystals: [Ba(C 13 H 9 )(18‐crown‐6)(pyridine)] + [C 13 H 9 ] − · pyridine ( 4a ) and [Ba(C 13 H 9 )(dibenzo‐18‐crown‐6)(pyridine)] + [C 13 H 9 ] − · 2 pyridine ( 5a ). The structures of 4a and 5a could be determined by X‐ray diffraction, too. The complexes 4a and 5a have a salt‐like structure with a complex [Ba(C 13 H 9 )(18‐crown‐6)(pyridine)] + ‐cation and a free fluorenide anion.