A novel hybrid terpyridine–pyrimidine ligand and the supramolecular structures of two of its complexes with Zn(II) and acetylacetonato: The underlying role of non-covalent π⋯π contacts and C–H⋯X(O, N, π) hydrogen bonds

• A novel hybrid terpyridine–pyrimidine ligand (L1) was synthesized.
• The reaction of L1 with Zn(acac)2 gives simultaneously 1 and 2.
• 1 and 2 present C–H⋯N bonds generating planar 2D aromatic structures.
• The spacings between the 2D arrays strongly suggests a π⋯π linkage among them.

The novel 4′-[4-(pyrimidin-5-yl)phenyl]-4,4′:6′,2″-terpyridine (L1) ligand reacts with Zn(acac)2 (acac = acetylacetonato) to give the monomeric complex [Zn(acac)2(L1)2] (1) and the coordination polymer [Zn(acac)2(μ-L1)]n (2). The structure of 1 consists of a Zn(II) cation sitting on an inversion centre, surrounded by a slightly elongated octahedral environment, defined by two trans N(4-pyridyl) atoms from a pair of mondentate L1 ligands, and four O atoms from two chelating acac anions. The polymeric structure of 2 presents a similar though non-symmetric Zn(acac)2 unit, since the two coordinated N atoms come from two different donor moieties of L1: the 4-pyridyl and the pyrimidinyl. Both compounds present weak C–H⋯N contacts generating 2D aromatic structures, complemented by π⋯π contacts plane-stacking giving raise to 3D structures and further stabilized by C–H⋯O and C–H⋯π interactions.

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