<p>Metal–organic frameworks (MOFs) are a widely investigated class of crystalline
solids with tunable structures that make it possible to impart specific
chemical functionality tailored for a given application. However, the enormous
number of possible MOFs that can be synthesized makes it difficult to determine
which materials would be the most promising candidates, especially for
applications governed by electronic structure properties that are often
computationally demanding to simulate and time-consuming to probe
experimentally. Here, we have developed the first publicly available quantum-chemical
database for MOFs (the “QMOF database”), which consists of properties derived
from density functional theory (DFT) for over 14,000 experimentally synthesized
MOFs. Throughout this study, we demonstrate how this new database can be used
to identify MOFs with targeted electronic structure properties. As a
proof-of-concept, we use the QMOF database to evaluate the performance of
several machine learning models for the prediction of DFT-computed band gaps
and find that crystal graph convolutional neural networks are capable of
achieving superior predictive performance, making it possible to circumvent
computationally expensive quantum-chemical calculations. We also show how
unsupervised learning methods can aid the discovery of otherwise subtle structure–property
relationships using the computational findings in this work. We conclude by
highlighting several MOFs with low band gaps, a challenging task given the
electronically insulating nature of most MOF structures. The data and
predictive models generated in this work, as well as the database of MOF
structures, should be highly useful to other researchers interested in the
predictive design and discovery of MOFs for the many applications dictated by
quantum-chemical phenomena.<br></p>