The effect of temperature and pressure on the crystal structure of piperidine

BMC Chemistry

Table 2 Intermolecular contact distances in piperidine-d ₁₁ as determined by neutron powder diffraction, and molecule-molecule contact energies E estimated in PIXEL calculations

Contact	Symmetry operation	− E _COUL / kJmol ⁻¹	− E _POL / kJmol ⁻¹	− E _DISP / kJmol ⁻¹	E _REP / kJmol ⁻¹	− E _TOT / kJmol ⁻¹	Distance/Å	Distance/Å	Distance/Å
T or P							T = 2 K	P = 0.22 GPa	P = 1.09 GPa
Contacts formed within H-bonded chains
1. N1…H1-N1	[−x + 1,y − ½, −z + ½]	30.5	11.8	19.2	38.9	22.7	2.141(3)	2.18	2.09
2. N1-H1…N1	[−x + 1,y + ½, −z + ½]	30.5	11.8	19.2	39	22.6	2.141(3)	2.18	2.09
3. C1-H2…H5	[x,y + 1,z]	4.2	1.9	15.5	13.4	8.2	2.365(6)	2.41	2.27
4. C2-H5…H2	[x,y − 1,z]	4.2	1.9	15.5	13.4	8.2	2.365(6)	2.41	2.27
Contacts formed between H-bonded chains
5. C2-H4…H2	[−x + 2,y − ½, −z + ½]	2.2	1.2	12.1	9.5	6.0	2.373(9)	2.42	2.31
6. C1-H2…H4	[−x + 2,y + ½, −z + ½]	2.2	1.2	12.1	9.5	6.0	2.373(9)	2.42	2.31
7. C4-H8…H6	[−x + 2, −y, −z + 1]	2.4	1.0	11.2	8.8	5.7	2.446(14)	2.49	2.38
8. C5-H11…H9	[−x + 1, −y, −z + 1]	3.0	1.5	10.5	9.7	5.4	2.382(13)	2.44	2.26
9. C5-H10…H3	[x, −y + ½,z + ½]	1.1	0.4	6.8	3.9	4.4	2.588(9)	3.04	2.51
10. C1-H3…H10	[x, −y + ½,z − ½]	1.1	0.4	6.8	3.9	4.4	2.588(9)	3.04	2.51
11. C4-H8…H5	[x, −y − ½,z + ½]	1.7	0.7	8.0	6.3	4.1	2.443(6)	2.51	2.33
12. C2-H5…H8	[x, −y − ½,z − ½]	1.7	0.7	8.0	6.3	4.1	2.443(6)	2.51	2.33

The subscripts COUL, POL, DISP, REP and TOT refer to Coulombic, polarisation, dispersion, repulsion and total energy terms. Distances from the high-pressure measurements are quoted without uncertainties because the piperidine molecules were treated as rigid bodies during refinement.

ISSN: 2661-801X