3D pillared-layer coordination frameworks constructed from 4-(1,2,4-triazole)benzoic acid and different [M(HCOO)]n layers

• Two 3D nets are obtained from CdII or PbII, HCOO− and 4-(1,2,4-triazole)benzoic acid.
• Formate is in situ synthesized from the hydrolysis of DMF in hydrothermal condition.
• Different arrangements of [M2(HCOO)2] units result in diverse 2D polymeric layers.
• Self-interpenetrating and unusual non-entangled networks are afforded.

Two distinct pillared-layer frameworks [M(HCOO)(4-tba)]n (M = Cd for 1 and Pb for 2) have been prepared from 4-(1,2,4-triazole)benzoic acid (4-Htba) and M(NO3)2 salts by using the solvothermal method in DMF. During the reaction, formate anion is in situ obtained as the hydrolyzate of DMF. Single crystal X-ray diffraction reveals that 1 displays a 3D self-interpenetrating (3,3,4,6)-connected network of (4.6.8)(4.64.8)(4.66.87.10)(4.82) topology whereas 2 presents a 3D unusual (3,3,6,6)-connected network with the point symbol of (4.62)2(42.6)2(42.66.87)(44.66.85). Their structural divergences should be properly attributed to the fact that the similar [M2(HCOO)2] secondary building units were arranged in different directions along the b axis to result in different [M(HCOO)]n+ layers in 1 and 2. In addition, thermal stability and luminescent properties of both complexes are also studied.

This work presents two distinct 3D CdII and PbII pillared-layer frameworks consisting of diverse [M(HCOO)]n+ polymeric layers and 4-(1,2,4-triazole)benzoate organic struts, which show the interesting self-interpenetrating and unusual non-entangled topological networks.Figure optionsDownload as PowerPoint slide