Bicyclic guanidine superbase carboxylate salts for cellulose dissolution

Gazagnaire, Eva; Helminen, Jussi; King, Alistair W. T.; Golin Almeida, Thomas; Kurten, Theo; Kilpeläinen, Ilkka

doi:10.1039/d4ra01734j

Cited by 2 publications

(1 citation statement)

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“…Numerous natural products contain the amidino and guanidino groups [ 167 , 168 ]. Strong organic nitrogen bases are also used as ionic liquids [ 169 , 170 , 171 , 172 ], ligands in metal chelation [ 173 ], and reference bases in PA/GB measurements [ 18 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 51 , 52 , 53 , 54 , 55 , 65 , 85 , 86 , 87 ]. Figure 15 summarizes the most significant fields in which organic nitrogen superbases are found.…”

Section: Overview and Prospectsmentioning

confidence: 99%

Strong Bases and beyond: The Prominent Contribution of Neutral Push–Pull Organic Molecules towards Superbases in the Gas Phase

Raczyńska,

Gal,

Maria

2024

IJMS

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In this review, the principles of gas-phase proton basicity measurements and theoretical calculations are recalled as a reminder of how the basicity PA/GB scale, based on Brønsted–Lowry theory, was constructed in the gas-phase (PA—proton affinity and/or GB—gas-phase basicity in the enthalpy and Gibbs energy scale, respectively). The origins of exceptionally strong gas-phase basicity of some organic nitrogen bases containing N-sp3 (amines), N-sp2 (imines, amidines, guanidines, polyguanides, phosphazenes), and N-sp (nitriles) are rationalized. In particular, the role of push–pull nitrogen bases in the development of the gas-phase basicity in the superbasicity region is emphasized. Some reasons for the difficulties in measurements for poly-functional nitrogen bases are highlighted. Various structural phenomena being in relation with gas-phase acid–base equilibria that should be considered in quantum-chemical calculations of PA/GB parameters are discussed. The preparation methods for strong organic push–pull bases containing a N-sp2 site of protonation are briefly reviewed. Finally, recent trends in research on neutral organic superbases, leaning toward catalytic and other remarkable applications, are underlined.

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