Guanidine - Wikipedia
Guanidine is the compound with the formula HNC(NH 2) 2. It is a colourless solid that dissolves in polar solvents. It is a strong base that is used in the production of plastics and explosives .
Why there is a huge difference between the basicity of urea and guanidine?
2019年12月22日 · Thus, basically, it comes down to protonation ability of oxygen versus nitrogen. Oxygen is more electronegative than that of nitrogen, thus like to retain its lone pare better than nitrogen (cf. basicity of water and ammonia). Therefore, in that sense alone, guanidine is a better base than urea. References:
Basicity of Amidines and Guanidines - Unacademy
Because of the resonance stability and efficient solvation by water molecules, guanidines are more basic than amidines. The pkb value of guanidines was found to be 13.6. Amidines and guanidines are organic compounds with the chemical formula of …
5 Key Basicity Trends of Amines – Master Organic Chemistry
2017年4月26日 · Another example of how basicity of nitrogen can be increased by attachment to pi-donors is found in guanidines. In guanidine there are two pi-donating NH 2 groups which can donate electron density to the (pi-accepting) C=NH.
Substituent effects on the basicity (p - RSC Publishing
Replacing the guanidine group of 1b by a 2-iminoimidazolidine group (1a: p K a = 10.24) leads to a drop in the basicity of the molecule (Δp K a = −0.66). Changing the phenyl ring of 1a for a 2-pyridinyl (19a) or a 3-pyridinyl (16a) group has a strong effect on the p K a decrement (Δp K a = −0.79 and −1.25, respectively).
organic chemistry - Comparing the basicities of guanidine, …
2015年12月12日 · In terms of the resonance structures available to the conjugate acids: DH + has 0 resonance structures. Judging by this, C should be the most basic, as its conjugate acid is most stabilised by resonance. However, it turns out that guanidine A is more basic, despite its conjugate acid having fewer resonance structures. Why is this the case?
Upon protonation, guanidine forms a guanidinium cation which positive charge is delocalized and can be presented in the resonance forms (Fig. 1b). That is why guanidine possesses strong basic properties (рКb = 0.4) which are comparable to those of …
The study of the quantitative effect of diverse substituents on the basicity of aryl guanidine and 2-(arylimino)imidazolidine derivatives is useful for medicinal chemists working with biologically relevant guanidine-containing molecules. 1. Introduction. The guanidine group of the amino acid arginine is ubiquitous in Nature.
‘Guanidine is categorized as an organosuperbase with amine basicity due to the resonance stabilization of its conjugated acids’ is the recurrent way in which Ishikawa describes the particular strongly basic property of this system (Figure 2). 3 In …
The coordination chemistry of guanidines and guanidinates
2001年4月1日 · It has long been speculated that the exceptionally high basicity of guanidine (pK a =13.6) is associated with a form of aromaticity associated with the delocalisation of the six π-electrons across the symmetric Y-shaped CN 3 unit in the guanidinium cation, and the term Y-aromaticity has been coined to describe this [2]. However, this remains ...