The crystal structure of propane-1-aminium-2-carbamate, C 4 H 10 N 2 O 2

C 4 H 10 N 2 O 2 , monoclinic, Cc (no. 9), a = 9.5726(8) Å, b = 9.2271(9) Å, c = 7.4577(7) Å, β = 115.295(3) ° , V = 595.56(9) Å 3 , Z = 4, R gt ( F ) = 0.0520, wR ref ( F 2 ) = 0.1436, T = 298 K .


Source of materials
In a representative experiment propane-1,2-diamine (7.4 mg, 0.10 mmol) was dissolved in 6 mL of 95 percent ethanol, then the carbon dioxide were bubled into the solution under stirring for 5 min.The solution was filtered into a test tube and left standing at room temperature.After ca. 15 days colorless block crystals were collected.

Experimental details
The C-bound H atoms were geometrically placed (C-H = 0.95-0.98Å) and refined as riding with U iso (H) = 1.2-1.5 U eq (C).The N-bound H atoms were located in a difference Fourier map but were refined with a distance restraint of N-H = 0.86-0.89[3]

Comment
Organic acid-base salt has always been a hotspot of crystal engineering that can afford an alternative but efficient way for enhancing the physicochemical properties of a target molecule. 4Meanwhile, salts are also known as the paradise of the material science. 5Therefore, organic salts have attracted considerable interest and found their potential application in various fields of pharmaceutical, 6 energetic, 7 and photovoltaics industries. 8In this case, salts derived from the organic carboxylic acid and a range of nitrogenous bases of organic amine has been explored widely. 9Yet the carbonate salts of the organic bases were rare 10 in comparison with other organic carboxylic acids derived organic salts on account of its relative weak acidity.Although reactions of CO 2 with the primary and secondary amines, including the cyclic ones and those resulting in the salts of the amine and the corresponding carbamic acid, have been reported, they usually produce powder or amorphous solids.2][13][14][15][16][17][18] The reported crystal structures demonstrate that in many cases half of the molecules retain the amine group while the remaining half form a carbamate moiety resulting from the carbonation of the amino group.To the best of our knowledge, there were some reports on the salts of propane-1,2-diamine. 19 During the carbonation, the 2-amine form a carbamic acid via the addition reaction with the carbon dioxide, the 1-amine acted as the hydrogen bond acceptor for the H from the carbamic acid to form the carbonated adduct, resembling the zwitterionic piperazinium-4-carboxamide trihydrate. 20In the asymmetric unit there existed a propane-1-aminium-2-carbamate (Figure 1).The O(1)-C(4)/C(4)-O(2) (1.275(4)/1.269(4)Å) are almost equal to each other within the experimental error with the minor difference of 0.006 Å, telling the equal distribution of the negative charge on both the O atoms and supporting the existence of the carbamate.All the H attached to the N atoms were involved in the N-H⋯O hydrogen bond, the both O atoms at the carboxylate each had two N-H⋯O hydrogen bonds.The zwitterionic propane-1-aminium-2-carbamate were linked by the N-H⋯O hydrogen bond of 2.733(4) % A from one H of the NH + 3 and one O at the CO − 2 , establishing 1D chain.The chains were joined together by the N-H⋯O hydrogen bond of 2.801(4) Å from the second H of the NH + 3 and the same O at the CO − 2 the above N-H⋯O hydrogen bond, N-H⋯O hydrogen bond of 2.934(4) Å from the H of the NHCO − 2 and the other O at the CO − 2 , and the CH 2 -CH contact with the C-C/H-H = 3.988/2.145Å to establish the 2D sheet located in the crystallographic ac plane.The sheets were stacked in the crystallographic b-cell by the N-H⋯O hydrogen bond of 2.806(3) Å from the third H of the NH + 3 and one O at the CO − 2 , CH 2 -O contact of 3.367 Å from the CH 2 linker and the CO − 2 , and the CH 2 -C contact of 3.631 Å from the CH 2 linker and the CO − 2 to make 3D net.The net enclosed the R rings according to Bernstein 21 .

Table  :
Data collection and handling.

Table  :
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å  ).