Six triangular silver(I) or gold(I) 4-chloro/iodo-3,5-diphenyl pyrazolates, as well as a triangular silver(I) 4-methyl-3,5-diphenyl pyrazolate, have been synthesized and structurally characterized by single-crystal X-ray diffraction. Comparison and inspection of the Ag/Au⋯Cl/I distances, geometries of C–Cl/I bonds with respect to the Ag₃ or Au₃ triangles, and crystal packing diagrams verify the existence of Ag₃⋯Cl/I or Au₃⋯I interactions in some of the structures of the trimers, which are strong enough to impart a substantial effect on the spatial arrangement of the trimers in their solid states. Density function theory (DFT) calculations on the trimers give the molecular electrostatic potential (MEP) surfaces and HOMO/LUMOs, which support that the observed M₃⋯X structural motifs can be understood on the basis of a weak acid–base interaction having contributions from both ionic δ⁺⋯δ⁻ attraction and covalent LUMO–HOMO overlap. Calculations also show the existence of the so-called “σ-hole” and the secondary effect to it on the halogen atoms; the structural roles played by them were discussed based on the crystal structures.

中文翻译：

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银（i）或金（i）4-卤代的3,5-二苯基吡唑并三聚体†的晶体结构中涉及卤素的弱相互作用

已经合成了六种三角形的三氯银（I）或金（I）4-氯/碘-3,5-二苯基吡唑酸酯，以及结构上表征的三角形的三价银（I）4-甲基-3,5-二苯基吡唑酸酯通过单晶X射线衍射。比较和检查Ag / Au⋯Cl / I距离，相对于Ag ₃或Au ₃三角形的C–Cl / I键的几何形状，以及晶体堆积图验证了Ag ₃ ⋯Cl / I或Au _3的存在三聚体在某些结构中的相互作用非常强，足以对三聚体在固态时的空间排列产生实质性影响。在三聚体上的密度泛函理论（DFT）计算得出分子静电势（MEP）表面和HOMO / LUMO，这表明可以在弱酸碱相互作用的基础上理解所观察到的M ₃ ⋯X结构基序从两个离子δ ⁺ ⋯δ ^-引力和共价LUMO-HOMO重叠。计算还表明存在所谓的“σ-孔”以及它对卤素原子的次级影响。根据晶体结构讨论了它们所起的结构作用。