145757-19-3Relevant academic research and scientific papers
Inorganic hybrid analogues of Thiele's and Chichibabin's hydrocarbons. Spectroscopy, electrochemistry, and structure
Lichtblau, Alexander,Hausen, Hans-Dieter,Schwarz, Wolfgang,Kaim, Wolfgang
, p. 73 - 78 (2008/10/08)
The formal substitution of external C=C bonds in quinonoid hydrocarbons such as 7,7,8,8-tetraaryl-p-quinodimethanes and 1,1′-biphenyl-4,4′-diylbis(diarylmethyl) compounds with the isoelectronic B=N function has occurred in 1,4-bis(dimesitylboryl)-1,4-dihydropyrazine (1) and 1,1′-bis(dimesitylboryl)-1,1′,4,4′-tetrahydro-4,4′- bipyridylidene (2). These new inorganic hybrid analogues of Thiele's and Chichibabin's hydrocarbons are sufficiently electron-rich to allow chemical and electrochemical one-electron oxidation despite the strong π acceptor effect of BMes2 substituents. Unusual small 11B and 14N EPR/ENDOR coupling constants of the cation radicals 1?+ and 2?+ indicate a considerable degree of π bonding within the B=N units. The crystal structure of 2 as bis(benzene) solvate reveals a significantly higher degree of π electron localization than Chichibabin's hydrocarbon. The B-N distance of 144.4 (3) pm is close to that in borazine or hexagonal boron nitride. Hu?ckel MO calculations were used to interpret EPR/ENDOR, electrochemical, and structural results. Crystal data for 2·2C6H6 at -100°C: Triclinic P1, Z = 1, a = 802.7 (2) pm, b = 1020.3 (3) pm, c = 1499.6 (5) pm, α = 97.12 (1)°, β = 92.85 (1)°, γ = 98.32 (1)°.
