New Heterometallic Hybrid Polymers Constructed with Aromatic Sulfonate-Carboxylate Ligands: Synthesis, Layered Structures, and Properties

Three novel alkali metal-cadmium coordination polymers [K2Cd(Hsb)(4)(H2O)(6)](3n) 1, [NaCd(sip)-(DMF)(2)(H2O)(2n) 2, and [NaCd2(sip)(2)(DMF)(2)(H2O)(2)](2n)center dot 2nHdeta center dot 2nH(2)O 3 (H(2)sb = 4-sulfobenzoic acid, H(3)sip = 5-sulfoisophthalic acid) have been synthesized and characterized by single crystal X-ray diffraction and spectroscopic and thermogravimetric methods. The solid state structure of 1 consists of inorganic layers, formed from Na2O10 and CdO6, polyhedral units, bridged via the sulfonate site of the ligand. The layers are pillared by the organic portions of the ligands to form a three-dimensional framework classified as (IO1)-O-2. Compounds 2 and 3 display inorganic organic hybrid layers arranged in 3D via nonspecific (hydrophobic) interactions between the DMF ligands. The two-dimensional frameworks of the layers are classified as (IO1)-O-1 (in 2) and 1(0)O(2) (in 3). The guest diethylammonium ions in 3 are arranged in hydrophobic channels along the [011] crystallographic direction and circumvented by the DMF ligands.