R3N+N?: a substituent with extreme electronic effects

Abstract

Basicity, infrared and x‐ray results are reported which show the uniquely high electron‐donor effect of R3N+N− substituents. An explanation is offered in terms of theoretically calculated resonance, field and electronegativity σ substituent constants. Large values of the calculated first‐order hyperpolarizabilities in the R3N+N−(CHCH) nNO2 series suggest the introduction of the R3N+N− substituents in the synthesis of push–pull conjugated structures for second‐order non‐linear optics. Copyright © 2000 John Wiley & Sons, Ltd.

The hydrogen bond acidity and other descriptors for oximes

“…Once a 2 H is known, the general equation, eqn (4), 7 can be used to estimate the 1 : 1 complexation constant of the oximes or of the hydroxylamine with any base for which the 1 : 1 hydrogen bond basicity b 2 H has been determined. [8][9][10][11] log…”

“…There is also a set of GLC data on a Perkin-Elmer column that includes acetone oxime. 22 The relevant equation is eqn (9), making a total of 16 equations for acetone oxime. Details of the calculations for acetone oxime are in Table 6; the standard deviation between observed and calculated values is only 0.040 log units.…”

“…1,4 The defining equations for α 2 H are eqn (1), 4 where K is the 1:1 complexation constant for an acid against a reference base B, eqn (2) in which log K is put on a general scale of hydrogen bond acidity K A H , and finally eqn (3) is known, the general equation, eqn (4), 7 can be used to estimate the 1:1 complexation constant of the oximes or of the hydroxylamine with any base for which the 1:1 hydrogen bond basicity β 2 H has been determined. [8][9][10][11] Log K = (7.354* α 2…”

Electronic and Molecular Structure of Aminimides (1-Acyl-2,2,2-trimethyldiazan-2-ium-1-ide). 1. Formaminimide (HCON-N+Me3)

“…For example, the ylide segment -N -N + -(CH 3 ) 3 is claimed to be the strongest electron donor among the uncharged organic substituents. 4 Therefore, one might expect, for example, that the insertion of the CON -N + functionality in an appropriate position within a polyamide chain would strengthen the hydrogen bonding even more than an amide functionality. Indeed, a R-CON -N + R 1 R 2 R 3 tetrapeptide isostere scaffold was found to be a more potent inhibitor of HIV-1 protease than the parent peptide.…”

“…Indeed, the hydrogen bond basicity of oxygen in benzoyl-2,2,2-trimethyldiazan-2-ium-1ide (C 6 H 5 -CON -N + (CH 3 ) 3 ) is larger than that of the oxygen in N,N-dimethylbenzamide, (C 6 H 5 -CON(CH 3 ) 2 ). 4 Additionally, the ylide structure of RCON -N + R 1 R 2 R 3 provides an intrinsic large dipole moment, which would ensure stronger interaction with polar compounds or polar substructure. Therefore, it is not surprising that aminimides have been studied as pharmacophores and nonlinear optical materials.…”