Zirconium Metal–Organic Frameworks Assembled from Pd and Pt PNNNP Pincer Complexes: Synthesis, Postsynthetic Modification, and Lewis Acid Catalysis

Author(s)
B. Reiner , N. T. Mucha , A. Rothstein , J. S. Temme , Pu Duan , Klaus Schmidt-Rohr , B. M. Foxman and Casey R. Wade #
Publisher
Inorg. Chem.
Year
2018
Volume
57
Pages
2663-2672
DOI
https://doi.org/10.1021/acs.inorgchem.7b03063

Abstract

Carboxylic acid-functionalized Pd and Pt PNNNP pincer complexes were used for the assembly of two porous Zr metal–organic frameworks (MOFs), 2-PdX and 2-PtX. Powder X-ray diffraction analysis shows that the new MOFs adopt cubic framework structures similar to the previously reported Zr6O4(OH)4[(POCOP)PdX]3, [POCOP = 2,6-(OPAr2)2C6H3); Ar = p-C6H4CO2–, X = Cl–, I–] (1-PdX). Elemental analysis and spectroscopic characterization indicate the presence of missing linker defects, and 2-PdX and 2-PtX were formulated as Zr6O4(OH)4(OAc)2.4[M(PNNNP)X]2.4 [M = Pd, Pt; PNNNP = 2,6-(HNPAr2)2C5H3N; Ar = p-C6H4CO2–; X = Cl–, I–]. Postsynthetic halide ligand exchange reactions were carried out by treating 2-PdX with Ag(O3SCF3) or NaI followed by PhI(O2CCF3)2. The latter strategy proved to be more effective at activating the MOF for the catalytic intramolecular hydroamination of an o-substituted alkynyl aniline, underscoring the advantage of using halide exchange reagents that produce soluble byproducts.