Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H₂O)₄ in [Zn(OAc)₂(μ‐bpe)]⋅2 H₂O: X‐ray and Neutron Diffraction Studies

Abstract

The reaction of 4,4'-bipyridylethane (bpe) and 4,4'-dipyridyl disulfide (dpds) with Zn(OAc)2.2H2O has led to the formation of two coordination polymers, [Zn(OAc)2(mu-bpe)].2H2O (1) and [Zn(OAc)2(mu-dpds)] (2). Both the compounds have zigzag coordination polymeric structures as revealed by X-ray crystallography. However, the presence of two lattice water molecules in 1 results in an interesting difference between the crystal structures. In 1, the carboxylate carbonyl oxygen atoms of the Zn(OAc)2 groups from two different adjacent zigzag polymers and four lattice water molecules form 24-membered hydrogen-bonded rings (graph set notation, R6 (6)(24)). One of the two bpe ligands associated with each Zn(II) center passes through the center of this ring to form a two-dimensional hydrogen-bonded coordination polymeric structure. In the solid state, the adjacent 24-membered hydrogen-bonded rings further fuse together through O-H...O hydrogen bonds among four waters to form cyclic (H2O)4. This results in a one-dimensional hydrogen-bonded ribbon-like polymer comprising fused alternating 24- and eight-membered O-H...O hydrogen-bonded rings. One of the bpe ligands passes through the center of the larger ring to produce an unexpected single self-penetrating three-dimensional hydrogen-bonded network with polyrotaxane-like association. A neutron diffraction study provides a detailed description of the hydrogen bonds involved.

Structural Diversity of Metallosupramolecular Assemblies Based on the Bent Bridging Ligand 4,4′-Dithiodipyridine

“…In UFAVED, twofold crystallographic rotation axes run through the centre of the disulfide moiety and the metal corner unit perpendicular to the direction of propagation of the polymer strands. [Zn(CH 3 COO) 2 (μ-dtdp)] n (FAYQUS) [80,81], [Zn(NCS) 2 (μ-dtdp)] n (CEBLUR) [58,81], [ZnCl 2 (μ-dtdp)] n (YEJDAU) [82] and [ZnBr 2 (μ-dtdp)] n [83] form an isomorphous series of arched chains, in which tetrahedrally coordinated Zn(II) ions are joined by dtdp. In each case, two monodentate-bound acetato (FAYQUS01), isothiocyanato (CEBLUR01) and chlorido (CEBLUR01) ancillary ligands complete the coordination sphere of Zn(II).…”

High-speed neutron Laue diffraction comes of age

“…In just a few hours it has yielded detailed atomic structural information on large organic molecules, e.g., Refs. [2][3][4][5][6], shown 2-D magnetic ordering in astounding clarity [7], revealed new magnetic structures [8], allowed full data collection from small crystals inside anvil pressure cells [9], and followed variations of bond lengths with temperature in fine detail [10].…”

Preparation, characterization and crystal structure of dinuclear zinc(II) carboxylate complex with 1-(pyridin-4-yl)ethanone and 4-methylbenzoate based ligands

“…Carboxylates constitute an important class of ligands in the formation of coordination compounds [16][17][18][19][20][21][22][23][24]. Because ambidentate nature of their can display a wide variety of metal coordination modes such as monodentate terminal, chelating, bidentate bridging and monodentate bridging modes ( Figure 1), which lead to several types of compounds [25][26][27].…”