Single-Crystal X-ray Diffraction
X-ray reflections were collected on a Rigaku Saturn CCD
area detector with graphite monochromated Mo–Ka radiation
(k = 0.71073 A˚ ). Data were collected and processed
using CrystalClear (Rigaku) software. Structures were
solved by direct methods and SHELX-TL [29] was used for
structure solution and least-squares refinement. The nonhydrogen
atoms were refined anisotropically. All hydrogen
atoms were fixed at idealized positions except for the N–H
and O–H hydrogen atoms which were located from the
difference Fourier map and allowed to ride on their parent
atoms in the refinement cycles. The O–H bond distance of
one of the hydroxyl groups of HQ in CBZ–HQ cocrystal
was found to be longer than usual in the normal refinement
cycles, and hence this distance was fixed using DFIX
command in the SHELX. For the calculation of hydrogen
bond metrices, all O–H, N–H, and C–H distances are
neutron normalized to 0.983, 1.009, and 1.083 A˚ , respectively.
Data collection and refinement details are listed in
Table 1, and pertinent hydrogen bond distances are provided
in Table 2.