In this work, we have directed our attention to the evaluation of closely related bis-pyridyl ligands N′-(pyridin-2-ylmethylene)picolinohydrazide (HL^I), N′-(pyridin-2-ylmethylene)nicotinohydrazide (HL^II) and N′-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide (HL^III) as linkers for Pb^II extended structures. The reaction of Pb(NO₃)₂ or Pb(ClO₄)₂ with an equimolar amount of HL^I–III in the presence of KSCN in EtOH at 60 °C leads to the formation of heteroleptic coordination polymers [Pb(HL^I)(NO₃)₂]_n, [Pb(L^II)(ClO₄)]_n and [Pb(HL^III)(NO₃)(NCS)]_n. The structures of all these complexes are highly dictated by both the structure of the parent organic ligand and the nature of inorganic anions. In all cases, the main structural motif is a zig-zag 1D coordination polymer, which can be further extended to higher dimensions due to tetrel bonds, N–H⋯O hydrogen bonds and π⋯π interactions. The formation of tetrel bonds was possible thanks to a hemidirected coordination sphere of the Pb^II atoms in all the described complexes. As a result, the overall coordination number of the metal center was found to be 10, 7 and 8 in [Pb(HL^I)(NO₃)₂]_n, [Pb(L^II)(ClO₄)]_n and [Pb(HL^III)(NO₃)(NCS)]_n, respectively. DFT calculations were performed in order to determine the nature of non-covalent interactions and stability of the obtained structures.

中文翻译：

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蝶形键设计的超分子铅（II）体系结构

在这项工作中，我们将注意力转移到了密切相关的双吡啶基配体N '-（吡啶-2-基亚甲基）吡啶并酰肼（HL ^I），N '-（吡啶-2-基亚甲基）烟酰肼（HL ^II）中和ñ ' - （1-（吡啶-2-基）亚乙基）异烟酰肼（HL ^III），作为铅接头^II延长结构。Pb（NO ₃）₂或Pb（ClO ₄）₂与等摩尔量的HL ^{I–III的反应}KSCN在60°C的乙醇中存在会导致形成杂配聚合物[Pb（HL ^I）（NO ₃）₂ ] _n，[Pb（L ^II）（ClO ₄）] _n和[Pb（HL ^III）（NO ₃）（NCS）] _n。所有这些配合物的结构都由母体有机配体的结构和无机阴离子的性质决定。在所有情况下，主要的结构基序都是Z字形的1D配位聚合物，由于t特键，N–H⋯O氢键和π⋯π相互作用，它可以进一步扩展到更高的尺寸。由于在所有描述的配合物中Pb ^II原子的半定向配位域，从而可能形成了蝶形键。结果，在[Pb（HL ^I）（NO ₃）₂ ] _n，[Pb（L ^II）（ClO ₄）] _n和[Pb（HL ^I）（NO ₃）₂ ] _n中，金属中心的总配位数为10、7和8。分别为[Pb（HL ^III）（NO ₃）（NCS）] _n。进行DFT计算以确定非共价相互作用的性质和所获得结构的稳定性。