A doubly mononuclear cobalt(II) complex [Co(Hpmt)2(N3)2]2 (1) (Hpmt = 2-(2-pyridylmethylamino)ethanesulfonic acid; N3 = azide anion) has been synthesized and structurally characterized. Single-crystal X-ray diffraction analysis showed that 1 has crystallized in orthorhombic crystal system, Cmc21 space group. In the two independent and identical complexes, the cobalt(II) centers are both hexa-coordinated in distorted CoN6 octahedrons. The reduced Schiff base ligand Hpmt displayed a new coordination mode of bidentate chelate (κ 2-N,N′). The careful comparisons between Hpmt upon coordination and as free acid form demonstrated that the conformation flexibility might be responsible for its multiple coordination modes. The N–H⋯O and C–H⋯N hydrogen bonds constructed the 3D network, and this mainly agreed with the Hirshfeld surface analysis results.

中文翻译：

---

叠氮阴离子构建的双单核钴(II)配合物和2-(2-吡啶甲基氨基)乙磺酸配体的新配位模式：结构、构象比较和赫什菲尔德表面分析

双单核钴(II)络合物 [Co(Hpmt)2（N3）2]2(1) (Hpmt = 2-(2-吡啶基甲基氨基)乙磺酸；N3=叠氮阴离子）已被合成并进行结构表征。单晶X射线衍射分析表明1以斜方晶系结晶，羧甲基纤维素21空间组。在两个独立且相同的配合物中，钴(II)中心均在扭曲的CoN中六配位6八面体。还原的希夫碱配体 Hpmt 显示出一种新的双齿螯合物配位模式（κ 2-氮,氮′）。配位后的 Hpmt 与游离酸形式之间的仔细比较表明，构象灵活性可能是其多种配位模式的原因。N-H⋯O和C-H⋯N氢键构建了3D网络，这与Hirshfeld表面分析结果基本一致。