Which of these molecules is the most basic?

NH3, NH2CH3, NH2NH2 or NH2OH?

I assume this is homework? If so, what do you think? Which part of the molecule is responsible for it being basic?

It is a part of theoretical investigation... computational chemistry... and i would like to compare calculation results with some theories. I am not sure if i am correct, but i was thinking about the nature of the group attached to NH2. Is it possible, that thanks to -CH3 substituent, which push electrones towards N atom, it makes the molecule more basic? It would tend to accept extra proton more then for example NH2OH, where -OH group withdraw the electrons...?

One thing to be aware of in comparing the basicities of ammonia and gradually more methyl-substituted amines is that one has to specify gas-phase versus in solution. The order of basicities is different.

It depends on the solvent (or lack of one).

no solvent and water?

no solvent and water?

 

Gas-phase acidities are obviously measured in the complete absence of solvent (my recollection is that mass spectrometry is involved, but I don't recall any details). Many pK_a values are measured in water, but many others are tabulated in DMSO. With respect to primary, secondary, and tertiary amines, the relative order of pK_a values is affected by how well the conjugate acid (which is a cation) is solvated by water, as well as electronic effects that are intrinsic to the cation.

Edited May 27, 20169 yr by BabcockHall

in my opinion form left to right of increase. Because basicity is mean to, localize and feed consist of electrons. So Nh2oh the most basic

 

i cant exactly explain im sorry i am not Good about english writting

Edited June 29, 20169 yr by Albert hofmann