Synthesis and X-ray Structures of Dilithium, Dipotassium, and Lithium−Potassium 2,6-Pyridyl-Bridged Bis-azaallyl Complexes

Treatment of dilithium dialkyl complex [{(CHSiMe 3 ) 2 C 5 H 3 N-2,6}{Li(TMEDA)} 2 ] ( 1 ) with organonitriles Bu t CN and Bu t NC afforded 2,6-pyridyl-bridged bis-azaallyl complexes [{{N(SiMe 3 )C(Bu t )CH} 2 C 5 H 3 N-2,6}{Li 2 (THF) 2 }] ( 2 ) and [{{N(Bu t )C(SiMe 3 )CH} 2 C 5 H 3 N-2,6}{Li 2 (TMEDA)}] ( 3 ). Similar reaction with PhCN afforded a solvent-separated ion complex [Li(TMEDA) 2 ][Li{{N(SiMe 3 )C(Ph)CH} 2 C 5 H 3 N-2,6}] ( 4 ). In situ reaction of (CH 2 SiMe 3 ) 2 C 5 H 3 N-2,6 with Bu n Li/Bu t OK in the presence of TMEDA, followed by the addition of PhCN, afforded a mixed lithium−potassium complex [{{N(SiMe 3 )C(Ph)CH} 2 C 5 H 3 N-2,6}{Li(Et 2 O)}{K(TMEDA)}] ( 5 ), dipotassium complex [{{N(SiMe 3 )C(Ph)CH} 2 C 5 H 3 N-2,6}{{K(TMEDA)} 2 ] ( 6 ), and 4 . Furthermore, sequential addition of the reagents in the order Bu n Li, Bu t CN, and Bu t OK to (CH 2 SiMe 3 ) 2 C 5 H 3 N-2,6 afforded a dimeric dipotassium compound [{{N(SiMe 3 )C(Bu t )CH} 2 C 5 H 3 N-2,6}{K 2 (Bu t CN)(TMEDA)}] 2 ( 7 ). X-ray structures of 2 − 7 showed that one of the metals is bonded to the ligand in [N -,N,N - ] tridentate-chelate fashion, while the other metal interacts with the π-orbitals of the azaallyl arm.