Deciphering\nthe Spatial Arrangement of Metals and\nCorrelation to Reactivity in Multivariate Metal–Organic Frameworks

Abstract

Thirty-six\nporphyrin-based metal–organic frameworks (MOFs)\nwith composition of <b>(M</b>_<b>3</b><b>O)</b>_<b>2</b><b>(TCPP-M)</b>_<b>3</b> and M₃O trigonal SBUs of various metals,\nMg₃O, Mn₃O, Co₃O, Ni₃O,\nand Fe₃O including mixed-metal SBUs, Mn_<i>x</i>Fe_3–<i>x</i>O, Ni_<i>x</i>Fe_3–<i>x</i>O, Co_<i>x</i>Ni_3–<i>x</i>O, Mn_<i>x</i>Co_3–<i>x</i>O, Mn_<i>x</i>Mg_3–<i>x</i>O, and Mn_<i>x</i>Ni_3–<i>x</i>O were synthesized\nand characterized. These multivariate MOFs (MTV-MOFs) were examined\nby X-ray photoelectron spectroscopy, UV–vis diffuse reflectance\nspectra, and for the first time, their metal spatial arrangement deciphered\nand were found to exist in the form of either domains or well-mixed.\nWe find that MTV-MOFs with well-mixed metals in their SBUs, rather\nthan the SBUs having one kind of metal but different from one SBU\nto another, perform better than the sum of their parts in the test\nreaction involving the photo-oxidation of 1,5-dihydroxynaphthalene.