From Chain to Network: Design and Analysis of Novel Organic−Inorganic Assemblies from Organically Functionalized Zinc-Substituted Polyoxovanadates and Zinc Organoamine Subunits

A series of novel organic−inorganic assemblies, [Zn(Meen)2]2[(4,4‘-bipy)Zn2As8V12O40(H2O)] (1), [Zn(en)2(H2O)][Zn(en)2(4,4‘-bipy)Zn2As8V12O40(H2O)]·3H2O (2), [{Zn(en)3}2{Zn2As8V12O40(H2O)}]·4H2O·0.25bipy (3) and [Zn2(en)5]{[Zn(en)2][(bpe)HZn2As8V12O40(H2O)]2}·7H2O (4) [en = ethylenediamine, Meen = 1,2-diaminopropane, 4,4‘-bipy
= 4,4‘-bipyridine, and bpe = 1,2-bis(4-pyridyl)ethane] constructed from organically modified Zn-substituted
polyoxovanadates and zinc organoamine subunits have been synthesized. Each anion cluster of compound 1 is
directly linked by the 4,4‘-bipy ligand into a one-dimensional (1D) straight chain. The secondary metal complex
[Zn(Meen)2]2+ acts as an isolated countercation. The 1D chain structure of 2 is similar to that of 1 but sinuate
because of the secondary metal complex [Zn(en)2]2+ decorated on the anion cluster. The en ligands covalently
bonding to the surface anion of 3 not only support the secondary metal complex [Zn(en)2]2+ but also coordinate to
another anion through the secondary metal complex [Zn(en)2]2+ bridge to form an “eight-shaped” chiral helix. The
unprecedented 2D layer of compound 4 with large nanosized inner rectangular cavities [33.669(6) ×14.720(8) Å]
is successfully achieved through the anion clusters polymerized first into chains by flexible organic ligands and
then secondary metal complexes bridged between the chains. The different coordination abilities and geometries
of the bidentate organodiamine ligands used in the four-reaction systems play important roles in the formation of
the final structures:  from straight chains to sinuate chains, to helical chiral chains, and finally to a 2D layer with
helices.