Synthesis, structures and properties of a family of four two-dimensional coordination polymers constructed from 5-hydroxyisophthalate

• Four 2D CPs based on 5-hydroxyisophthalate with d10 and Pb(II) ions were reported.
• 1 is an unusual 2D→3D polythreaded framework.
• 4 shows a binodal (4, 4)-connected 2D double-layer network with nanochannels.
• The materials 1, 2 and 4 show reversible dehydration–rehydration behaviours.
• Solid state fluorescent properties were investigated.

Four 2D coordination polymers (CPs) with different structures containing the multifunctional ligand 5-hydroxyisophthalate (5-OH-BDC2−), [Zn(5-OH-BDC)(btb)]·2H2O (1), [Cd(5-OH-BDC)(btp)(H2O)]·3H2O (2), [Cd(5-OH-BDC)(bth)2(H2O)]·H2O (3) and [Pb(5-OH-BDC)]·H2O (4) [btp=1, 3-bis(1,2,4-triazol-1-yl)propane, btb=1,4-bis(1,2,4-triazol-1-yl)butane, bth=1, 6-bis(1,2,4-triazol-1-yl)hexane] were obtained. 1–3 were synthesised hydrothermally, while 4 was obtained under ambient condition. The adjacent (2D→2D) polycatenated 2D layers of 1 polythread in a parallel manner to form an unusual 2D→3D polythreaded framework. 2 contains an undulated 2D (4, 4) network and further extends into an “embracing” double-layer structure through the C–H···π and π···π stacking interactions. 3 exhibits a non-interpenetrating 2D (4, 4)-network. 4 exhibits a 2D double-layered binodal (4, 4)-net containing oblong nanochannels with symbol (4363)2. Reversible dehydration–rehydration is observed in 1, 2 and 4, which fall within the category of “recoverable collapsing” and “guest-induced re-formation” frameworks, while 3 exhibits irreversible dehydration–rehydration behaviour. The solid state fluorescent properties of 1–4 have been investigated.

Among four 2D CPs reported, 1 is an unusual 2D→3D polythreaded framework. 4 exhibits 2D double-layered binodal (4, 4)-net containing nanochannels. Reversible dehydration–rehydration is observed in 1, 2 and 4.Figure optionsDownload as PowerPoint slide