Computational study of ground-state properties of μ2-bridged group 14 porphyrinic sandwich complexes

The structural properties of mu(2)-bridged porphyrinic double-decker complexes are investigated and the influence of various ligands, metals, substituents, and bridging atoms on the dominant structural motif is elucidated. A variety of quantum chemical methods including semiempirical (SQM) methods and density functional theory (DFT) is assessed for the calculation of ecliptic and staggered conformational energies. Local coupled cluster (DLPNO-CCSD(T1)) data are generated for reference. The r(2)SCAN-3c composite scheme as well as the B2PLYP-D4/def2-QZVPP approach are identified as reliable methods. Energy decomposition analyses (EDA) and localized molecular orbital analyses (LMO) are used to investigate the bonding situation and the nature of the inter-ligand interaction energy underlining the crucial role of attractive London dispersion interactions. Targeted modification of the bridging atom, e.g., by replacing O2- by S2- is shown to drastically change the major structural features of the investigated complexes. Further, the influence of different substituents of varying size at the phthalocyanine ligand regarding the dominant conformation is described.

Automated summary

This study investigates the structural properties of mu(2)-bridged porphyrinic double-decker complexes and elucidates the influence of various ligands, metals, substituents, and bridging atoms on the dominant structural motif. The use of different quantum chemical methods and analysis tools provides reliable calculations and insights into the bonding situation and inter-ligand interaction energy.