Coordination Polymers Bearing Angular 4,4′-Oxybis[N-(pyridin-3-ylmethyl)benzamide] and Isomeric Dicarboxylate Ligands: Synthesis, Structures and Properties

Reactions of the angular 4,4'-oxybis[<i>N</i>-(pyridin-3-ylmethyl)benzamide] (<b>L</b>) with dicarboxylic acids and transition metal salts afforded non-entangled {[Cd(<b>L</b>)(1,3-BDC)(H₂O)]∙2H₂O}_n (1,3-BDC = 1,3-benzenedicarboxylic acid), <b>1</b>; {[Cd(<b>L</b>)(1,4-HBDC)(1,4-BDC)_0.5]∙2H₂O}_n (1,4-BDC = 1,4-benzenedicarboxylic acid), <b>2</b>; {[Cu₂(<b>L</b>)₂(1,3-BDC)₂]∙1.5H₂O}_n, <b>3</b>; {[Ni(<b>L</b>)(1,3-BDC)(H₂O)]∙2H₂O}_n, <b>4</b>; {[Zn(<b>L</b>)(1,3-BDC)]∙4H₂O}_n, <b>5</b>; {[Zn(<b>L</b>)(1,4-BDC)]∙2H₂O}_n, <b>6</b>; and [Cd₃(<b>L</b>)₂(1,4-BDC)₃]_n, <b>7</b>, which have been structurally characterized by using single-crystal X-ray diffraction. Complexes <b>1</b>-<b>5</b> and <b>7</b> are 2D layers, giving (6⁴·8·10)(6)-2,4L3, (4²·8²·10²)(4²·8⁴)₂(4)₂, (4·5·6)(4·5⁵·6³·7)-3,5L66, (6⁴·8·10)(6)-2,4L3, interdigitated (8⁴·12²)(8)₂-2,4L2 and (3⁶·4⁶·5³)-<b>hxl</b> topologies, respectively, and <b>6</b> is a 1D chain with the (4³·6²·8)(4)-2,4C3 topology. The factors that govern the structures of <b>1</b>-<b>7</b> are discussed and the thermal properties of <b>1</b>-<b>7</b> and the luminescent properties of complexes <b>1</b>, <b>2</b>, <b>5</b> and <b>6</b> are investigated. The stabilities of complexes <b>1</b> and <b>5</b> toward the detection of Fe³⁺ ions are also evaluated.