The crystal structures, Hirshfeld surface analyses and energy frameworks of 8-{1-[3-(cyclo-pent-1-en-1-yl)benz-yl]piperidin-4-yl}-2-meth-oxy-quinoline and 8-{4-[3-(cyclo-pent-1-en-1-yl)benz-yl]piperazin-1-yl}-2-meth-oxy-quinoline

Abstract

The title compounds, 8-{1-[3-(cyclo-pent-1-en-1-yl)benz-yl]piperidin-4-yl}-2-meth-oxy-quinoline, C₂₇H₃₀N₂O (I), and 8-{4-[3-(cyclo-pent-1-en-1-yl)benz-yl]piperazin-1-yl}-2-meth-oxy-quinoline, C₂₆H₂₉N₃O (II), differ only in the nature of the central six-membered ring: piperidine in I and piperazine in II. They are isoelectronic (CH cf. N) and isotypic; they both crystallize in the triclinic space group P with very similar unit-cell parameters. Both mol-ecules have a curved shape and very similar conformations. In the biaryl group, the phenyl ring is inclined to the cyclo-pentene mean plane (r.m.s. deviations = 0.089 Å for I and 0.082 Å for II) by 15.83 (9) and 13.82 (6)° in I and II, respectively, and by 67.68 (6) and 69.47 (10)°, respectively, to the mean plane of the quinoline moiety (r.m.s. deviations = 0.034 Å for I and 0.038 Å for II). The piperazine ring in I and the piperidine ring in II have chair conformations. In the crystals of both compounds, mol-ecules are linked by C-H⋯π inter-actions, forming chains in I and ribbons in II, both propagating along the b-axis direction. The principal contributions to the overall Hirshfeld surfaces involve H⋯H contacts at 67.5 and 65.9% for I and II, respectively. The major contribution to the inter-molecular inter-actions in the crystals is from dispersion forces (E _dis), reflecting the absence of classical hydrogen bonds.

Keywords: Hirshfeld surface analysis; crystal structure; cyclo­pentene; dopamine D2; energy frameworks; hydrogen bonding; isoelectronic; isotypic; meth­oxy­quinoline; piperazine; piperidine; serotonin 5-HT1a.

Figure 1

A view of the mol­ecular structure of I, with atom labelling. The displacement ellipsoids are drawn at the 50% probability level.

Figure 2

A view of the mol­ecular structure of II, with atom labelling. The displacement ellipsoids are drawn at the 50% probability level.

Figure 3

A view of the structural overlap of compounds I and II (red); r.m.s. deviation 0.002 Å (Mercury; Macrae et al., 2020 ▸). The O and N atoms are shown as balls.

Figure 4

A view of the structural overlap of compounds II (red) and III (blue; Ullah & Altaf, 2014 ▸); r.m.s. deviation 0.071 Å (Mercury; Macrae et al., 2020 ▸). The O and N atoms are shown as balls.

Figure 5

A view along the a axis of the crystal packing of I. The C—H⋯π inter­actions are shown as dashed lines (see Table 1 ▸). Only the H atoms involved in these inter­actions have been included.

Figure 6

A view along the a axis of the crystal packing of II. The C—H⋯π inter­actions are shown as dashed lines (see Table 2 ▸). Only the H atoms involved in these inter­actions have been included.

Figure 7

The Hirshfeld surfaces of compounds (a) I, (b) II and (c) III, mapped over d _norm in the colour ranges of −0.1177 to 1.5125, −0.2113 to 1.3756 and −0.1475 to 1.8614 au., respectively.

Figure 8

The full two-dimensional fingerprint plots for compounds (a) I, (b) II and (c) III, and those delineated into H⋯H, C⋯H/H⋯C, O⋯H/H⋯O and N⋯H/H⋯N contacts.

Figure 9

The energy frameworks calculated for (a) I and (b) II, both viewed along the b axis direction, and (c) III, viewed along the a-axis direction, showing the electrostatic potential forces (E _ele), the dispersion forces (E _dis) and the total energy diagrams (E _tot).