Benchmark CCSD(T) and Density Functional Theory Calculations of Biologically Relevant Catecholic Systems

Approximate complete
basis set CCSD(T), MP2, and HF calculations
are performed for thirty-two catechol-containing complexes. These
complexes, which include metal-coordination, hydrogen-bonding, π-stacking,
and other, weaker interactions, are representative of the types of
noncovalent interactions that catechols undergo when binding to proteins
in the body, such as in the biosynthesis of dopamine. The catechols
studied include the neutral catechol and dinitrocatechol molecules,
as well as the charged dopamine and DOPAC molecules. Calculations
with twenty-one density functional theory methods with triple and
quadruple-ζ basis sets are evaluated against the CCSD(T) benchmarks
to ascertain their accuracy. It is found that MN15, M06-2X-D3, ωB97XD,
ωB97M-V, and CAM-B3LYP-D3 provide good accuracy when compared
with CCSD(T)/CBS calculations for these systems and may be used for
the study of relevant biological systems. The local DPLNO CCSD(T)
method is also evaluated against the CCSD(T)/CBS energies for a subset
of the complexes and found to agree within 1–3%, with a maximum
difference of 0.26 kcal/mol.