Rue Kelly, Raptis Raphael G
Department of Chemistry and Biochemistry, 11200 SW 8th Street, Miami, FL 33199, USA.
Acta Crystallogr E Crystallogr Commun. 2021 Aug 24;77(Pt 9):955-957. doi: 10.1107/S2056989021008604. eCollection 2021 Sep 1.
The structure of 4-chloro-1-pyrazole, CHClN, at 170 K has ortho-rhom-bic () symmetry and is isostructural to its bromo analogue. Data were collected at low temperature since 4-chloro-1-pyrazole sublimes when subjected to the localized heat produced by X-rays. The structure displays inter-molecular N-H⋯N hydrogen bonding and the packing features a trimeric mol-ecular assembly bis-ected by a mirror plane ( normal to ) running through one chlorine atom, one carbon atom and one N-N bond. The asymmetric unit therefore consists of one and one-half 4-chloro-1-pyrazole mol-ecules. Thus, the N-H proton is crystallographically disordered over two positions of 50% occupancy each.
4-氯-1-吡唑（CHClN）在170 K时具有正交（）对称性，且与其溴代类似物同构。由于4-氯-1-吡唑在受到X射线产生的局部热量时会升华，因此在低温下收集数据。该结构显示出分子间N-H⋯N氢键，堆积特征为三聚体分子组装，由一个穿过一个氯原子、一个碳原子和一个N-N键的镜面（垂直于）平分。因此，不对称单元由一个半4-氯-1-吡唑分子组成。因此，N-H质子在晶体学上在两个占有率均为50%的位置上无序分布。
