title: Very strong organosuperbases formed by combining imidazole and guanidine bases: synthesis, structure, and basicity.
abstract: New structural motives for organosuperbases, that are easy to prepare and highly basic are urgently required in many areas of chemistry. The synthesis of N,N'-bis(imidazolyl)guanidine bases (BIG bases) is reported. Their pKα  values are determined as 26.1-29.3 in THF. They are thus probably the strongest known phosphorous-free organic bases both in solution and in the gas phase. Calculations help to determine the structural and electronic factors giving rise to the high basicity.
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 16610 Prag 6 (Czech Republic) http://www.uochb.cz/web/structure/616.html; Laboratory for Synthesis and Self-Assembling of Organic, Molecules; Division of Physical Chemistry, Rudjer Boskovic Institut, Bijenicka c. 54, 10000 Zagreb (Croatia).
authors: Katarina
authors: K
authors: Vazdar
authors: Roman
authors: R
authors: Kunetskiy
authors: Jaan
authors: J
authors: Saame
authors: Karl
authors: K
authors: Kaupmees
authors: Ivo
authors: I
authors: Leito
authors: Ullrich
authors: U
authors: Jahn
keywords: UV/Vis spectroscopy; basicity; guanidine; organosuperbases; synthetic methods