Electronic Structure of a Metal−Organic Copper Spin-1/2 Molecule:  Bis(4-cyano-2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II)

The metal−organic molecule bis(4-cyano-2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II) (Cu(CNdpm)2) (C24H36N2O4Cu, Cu(II)) is a copper spin-1/2 system with a magnetic moment of 1.05 ± 0.04 μB/molecule, slightly smaller than the 1.215±0.02 μB/molecule for the larger size copper spin-1/2 system C36H48N4O4Cu·C4H8O (bis(4-cyano-2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II) 4,4‘-bipyridylethene−THF). There is generally good agreement between photoemission from vapor-deposited thin films of the C24H36N2O4Cu on Cu(111) and Co(111) and model calculations. Although this molecule is expected to have a gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, the molecule remains surprisingly well screened in the photoemission final state.