US EPA

7494198 

Journal Article 

New crystal structure of molecular complex 1-piperidine carboxylate-piperidinium-H2O studied by X-ray single crystal diffraction 

Jiang, H; Zhang, S; Jin, R; Ma, Y 

2007 

12 

6 

1099-1104 

English 

10.1007/s11859-007-0111-z 

Piperidine absorbs CO2 and H2O in air to form a molecular complex: piperidium-1-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was determined to be triclinic, space group P1̄ with a=0.648 6(8) nm, b=0.809 2(10) nm, c=1.357 1(16) nm, α=96.967(16)°, β=102.506(15)°, γ=104.202 (15)°, Z=2. The complex is stabilized via five hydrogen bonds between the three components, N-O electrostatic interaction and O-O interaction (electron transfer) between1-piperidinecarboxylate and H2O. Due to electron transference of carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of the free molecule of water. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein. © 2007 Wuhan University. 

Electron transfer; Hydrogen bond; Molecular complex; Piperidine; Single crystal