**4. Conclusions**

Three eight-fold interpenetrated 3D CPs with the (66)-**dia** topology have been successfully prepared by using angular **L** and the linear dicarboxylic acid 1,4-H2NDC. The Zn(II), Cd(II) and Co(II) metal centers of **1**–**3** adopt the distorted tetrahedral, pentagonal bipyramidal and octahedral/square pyramidal geometries, respectively, resulting in different coordination modes for the 1,4-NDC2<sup>−</sup> ligands and indicating that the structural topology is not subject to the metal geometry. Their structural stabilities are assessed particularly in the aqueous environments, revealing that complexes **1** and **2** with close-shell Zn(II) and Cd(II) ions are much more stable than **3** with the open-shell Co(II) ion. The surface areas and pore structures of **1** and **2** were observed via CO2 gas sorption measurements and the activated samples of **1** and **2** explored by emission spectra and PXRD patterns demonstrate efficient detection of mesitylene and Fe3+ ions with high selectivity and recyclability. This investigation oversees the sensing properties of the highly entangled bpba-based CPs toward VOCs and metal ions.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/10 .3390/polym13183018/s1. FT-IR spectra for **1**–**3** (Figure S1). PXRD patterns for **1**–**3** (Figures S2–S4). TGA curves for **1**–**3** (Figure S5). CO2 sorption isotherms of **1** and **2** (Figures S11–S13). Emission spectra for **1** and **2** (Figures S14 and S15). Sensing properties of reported compounds toward various aromatic VOCs (Table S1). Sensing properties of reported compounds toward Fe3+ ions (Table S2). Crystallographic data for **1**–**3** have been deposited with the Cambridge Crystallographic Data Centre, CCDC No. 2100027-2100029.

**Author Contributions:** Investigation, V.L. and Y.-T.L.; data curation, X.-K.Y. and M.G.; supervision, C.-H.L. and J.-D.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Ministry of Science and Technology, Taiwan: MOST 109-2113-M-033-009.

**Acknowledgments:** We are grateful to the Ministry of Science and Technology of the Republic of China for their support.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

