Estimation of coordination complex structure of O-Cu(I)-2-aminopyrimidine on a copper surface using X-ray photoelectron spectroscopy

XPS spectra for cleaned and a 2-aminopyrimidine treated copper plates have been measured from 0.0 to about 1000.0 eV. The spectral features of CU2p3/2 and O-1s peaks indicate Cu2O layer formation on the copper surface. High r esolution N-1s XPS spectra recorded for free 2-aminopyrimidine and 2-aminop yrimidine treated copper films indicate that 2-aminopyrimidine reacts with the copper surface forming a [O-Cu(I)-2-AP] complex on an oxidized underlay er. First principles molecular orbital calculations have been performed on an embedded model of 2-aminopyrimidine and on eight assumed surface model c luster complexes. The N 1s level in 2-aminopyrimidine is quantitatively wel l reproduced. Spectral features within 28 eV of the edge as well as absolut e energies are satisfactorily reproduced by the ground state calculation us ing a minimal basis set. The [O-Cu(I)-2-AP] surface models show theoretical spectra of Cu(I)-pyrimidine ring rr-complexes that agree well with the hig h resolution N-1s XPS data. (C) 2001 Elsevier Science B.V. All rights reser ved.