TY - JOUR
T1 - Metal Organo-Polymeric Framework via [2 + 2] Cycloaddition Reaction
T2 - Influence of Hydrogen Bonding on Depolymerization
AU - Park, In Hyeok
AU - Sasaki, Kenta
AU - Quah, Hong Sheng
AU - Lee, Eunji
AU - Ohba, Masaaki
AU - Lee, Shim Sung
AU - Vittal, Jagadese J.
N1 - Funding Information:
This work was supported by the Ministry of Education, Singapore (National University of Singapore Tier 1 Grant No. R-143-000-A12-114) and National Research Foundation of Korea (NRF) (2016R1A2A2A05918799 and 2017R1A4A1014595), South Korea. I.H.P. acknowledges the Overseas Postdoctoral Fellowship of Foresting Next-Generation Research Program through the NRF (2017R1A6A3A03006579).
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/3/6
Y1 - 2019/3/6
N2 - In the doubly interpenetrated metal-organic framework (MOF) structure with cds topology, [Zn 2 (bpeb)(dhbdc)(fa) 2 ], 1 (where bpeb = trans,trans,trans-1,4-bis[2-(4′-pyridyl)ethenyl]benzene, dhbdc = 2,5-dihydroxy-benzene-1,4-dicarboxylate, and fa = formate), the adjacent bpeb ligands are aligned in a slip-stacked manner infinitely, and the olefin pairs are aligned in parallel ready to undergo a quantitative photochemical [2 + 2] cycloaddition reaction. The single-crystal-to-single-crystal (SCSC) photoreaction under UV light yielded a non-interpenetrated [Zn 2 (poly-bppcb)(dhbdc)(fa) 2 ], 2 (where poly-bppcb = 1,3-(4,4′-bipyridyl)-2-phenylcyclobutane) in which the poly-bppcb polymer comprising cyclobutane rings are nicely integrated into the two-dimensional coordination polymeric sheet formed by [Zn 2 (dhbdc)(fa) 2 ]. This organic polymer can be depolymerized back to 1 by heating 2 at 250 °C in a hot air oven for 6 h. The cleavage of cyclobutane rings to bpeb ligands has been attributed to the hydrogen bonding of the two hydroxy groups in the dhbdc ligand. In a similar metal organo-polymeric framework with bdc ligand, the poly-bppcb could not be depolymerized. Thus, this study provided some new insights into the reversible cleavage of cyclobutane polymers. These polymeric materials based on cyclobutane may be environmentally benign as these can be depolymerized to yield easily disposable and degradable monomers.
AB - In the doubly interpenetrated metal-organic framework (MOF) structure with cds topology, [Zn 2 (bpeb)(dhbdc)(fa) 2 ], 1 (where bpeb = trans,trans,trans-1,4-bis[2-(4′-pyridyl)ethenyl]benzene, dhbdc = 2,5-dihydroxy-benzene-1,4-dicarboxylate, and fa = formate), the adjacent bpeb ligands are aligned in a slip-stacked manner infinitely, and the olefin pairs are aligned in parallel ready to undergo a quantitative photochemical [2 + 2] cycloaddition reaction. The single-crystal-to-single-crystal (SCSC) photoreaction under UV light yielded a non-interpenetrated [Zn 2 (poly-bppcb)(dhbdc)(fa) 2 ], 2 (where poly-bppcb = 1,3-(4,4′-bipyridyl)-2-phenylcyclobutane) in which the poly-bppcb polymer comprising cyclobutane rings are nicely integrated into the two-dimensional coordination polymeric sheet formed by [Zn 2 (dhbdc)(fa) 2 ]. This organic polymer can be depolymerized back to 1 by heating 2 at 250 °C in a hot air oven for 6 h. The cleavage of cyclobutane rings to bpeb ligands has been attributed to the hydrogen bonding of the two hydroxy groups in the dhbdc ligand. In a similar metal organo-polymeric framework with bdc ligand, the poly-bppcb could not be depolymerized. Thus, this study provided some new insights into the reversible cleavage of cyclobutane polymers. These polymeric materials based on cyclobutane may be environmentally benign as these can be depolymerized to yield easily disposable and degradable monomers.
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U2 - 10.1021/acs.cgd.9b00018
DO - 10.1021/acs.cgd.9b00018
M3 - Article
AN - SCOPUS:85062060402
SN - 1528-7483
VL - 19
SP - 1996
EP - 2000
JO - Crystal Growth and Design
JF - Crystal Growth and Design
IS - 3
ER -