1228693-63-7Relevant academic research and scientific papers
Synthesis of C-substituted t-BuNH-8,9-R,R′-nido-7,8,9-C 3B8H9 (R,R′ = H,H; MeH; Me,Me; Ph,H and Ph,Ph) tricarbollide compounds and their tautomeric conversions. Effect of substituents on tautomeric equilibria between neutral and zwitterionic forms
Bakardjiev, Mario,Holub, Josef,Stibr, Bohumil,Cisaova, Ivana
, p. 4186 - 4190 (2010)
Treatment of C-substituted nido dicarbadecaboranes 5,6-R′,R-5,6- C2B8H10 (1) (where R′,R = H,H (1a); H,Me, (1b); Me,Me, (1c); H,Ph, (1d) and Ph,Ph, (1e) with 1,8-bis-(dimethylamino) naphthalene (proton sponge = PS) and t-BuNC in CH2Cl2, followed by acidification, generated a series of pure neutral compounds 7-t-BuNH-8,9-R,R′-nido-7,8,9-C3B8H9 (N2) (where R,R′ = H,H (N2a); H,Me (N2b); Me,Me (N2c); H,Ph (N2d), and Ph,Ph (N2e)), each of which exhibits tautomerism. Dissolution of the substituted compounds (N2b-N2e) in protic solvents (PRS), such as MeCN and Me2CO, leads to tautomeric equilibrium with the zwitterionic tautomers 7-t-BuNH 2-8,9-R,R′-nido-7,8,9-C3B8H8 (Z2) (where R,R′= H,H (Z2a); H,Me (Z2b); Me,Me (Z2c); H,Ph (Z2d) and Ph,Ph (Z2e)), while the unsubstituted compound N2a exhibits absolute tautomerism - a complete conversion into the zwitterionic tautomer Z2a. The tautomeric behaviour of individual compounds is therefore strongly affected by the nature of the substituent, as assessed via NMR spectroscopy in terms of tautomerisation constants KT = CZ2/CN2 (where CZ2 and CN2 are equilibrium concentrations of Z2 and N2 forms in a given solvent). Individual tautomers were characterised by 11B and 1H NMR spectroscopy and the structure of the monomethylated N2b tautomer was determined by an X-ray diffraction study.
