Cyclic zinc organophosphate based expanded ditopic N,N′-metalloligands

Abstract

A new series of zinc phosphate based novel elongated ditopic N,N′-metalloligands [Zn(X-dipp)(pyterpy)]2·2MeOH (X= H (1), Cl (2), Br (3), I (4)], exemplifying expanded 4,4′-bipyridine spacer family, has been prepared by reacting 4′-(4′′-pyridyl)-2,2′:6′,2′′-terpyridine (pyterpy), 2,6-diisopropylphenyl phosphate (dippH2) or its para-halo functionalized derivatives X-dippH2 (X = Cl, Br, I) with Zn(OAc)2.2H2O in a mixture of solvents at room temperature. The formation of these metalloligands has been confirmed by their spectroscopic and analytical data. Solution and solid-state stability of these complexes have been confirmed by both mass spectroscopy and thermogravimetric analysis. The solid-state structures of 1–4 have further been established by single crystal X-ray diffraction studies, revealing that the N,N′-distance in these systems can be expanded approximately to 23 A, as against the 7 A separation observed for 4,4’-bipyridine. Compounds 2–4, which contain two pyridyl nitrogen centers and two C–X functionalities that are orthogonal to each other, could offer new possibilities in their use as metalloligand to build extended 2-D and 3-D solids. New zinc phosphate based elongated N,N′-ditopic metalloligands are reported. The N,N′-distance in these systems can be expanded approximately to 23 A which makes them novel for potential use in making 2D and 3D metal organic frameworks.