Cu(NH₃)_1-3 Complexes:  A Matrix Isolation ESR Study

Abstract

The interaction between Cu atoms and ammonia molecules cocondensed in argon matrices was examined by ESR. The observed spectra revealed the formation of Cu(NH3)1 - 3 complexes. The g tensors and the hyperfine coupling tensors for the Cu and N nuclei of the complexes were determined. All three complexes showed large, essentially isotropic Cu hyperfine coupling interaction corresponding to 50−60% of that observed for isolated Cu atoms. No hyperfine structures due to protons were discerned. It is thus concluded that these complexes are formed merely by the dative interaction of the NH3 lone pair electrons with vacant Cu 4s/4p valence orbitals. The unpaired electron resides in a Cu 4s/4p-hybridized orbital projected away from the ligand(s). The ESR spectrum of the monoligand complex Cu(NH3) showed reversible photoconversion to the second spectrum in accord with the photoisomerization process Cu(NH3) ↔ HCuNH2 reported in an earlier IR study. The second spectrum, though partially obscured by other signals, revealed a pattern consistent with the ionic character H-Cu2+(NH2)- where the unpaired electron resides in the Cu 3d z 2 orbital.

Comparative Study of the Bonding in the First Series of Transition Metal 1:1 Complexes M−L (M = Sc, ..., Cu; L = CO, N2, C2H2, CN-, NH3, H2O, and F-)

“…M(H 2 O) and M(NH 3 ) Complexes. The M(H 2 O) and M(NH 3 ) complexes have been observed in the gas phase or at low temperature in matrixes. − On the other hand, there is an important quantum chemical literature on these systems. − As the electronic structure of these ligand forbids any π back-donation, the interaction with the metal atom is expected to be weak and dominated by the multipole-induced multipole induction forces. Therefore, one can expect, on one hand, ground-state spin multiplicities identical for complexes and free metal atoms and, on the other hand, geometries similar to those of the hydrogen-bonded complexes of water and ammonia with the metal ligand bond pointing in the direction of a lone pair.…”

“…The M(H 2 O) and M(NH 3 ) complexes have been observed in the gas phase or at low temperature in matrixes. [93][94][95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111] On the other hand, there is an important quantum chemical literature on these systems. [112][113][114][115][116][117][118][119][120][121] As the electronic structure of these ligand forbids any π backdonation, the interaction with the metal atom is expected to be weak and dominated by the multipole-induced multipole induction forces.…”

Interaction of CH2OH with silver cation in Ag–A/CH3OH zeolite: A DFT study

“…Atoms or small metal clusters trapped in various inert gas matrices they can form complexes with organic molecules usually unstable in normal conditions. The interactions of silver, copper or nickel with organic molecules and radicals stabilized in different matrices have been studied by various experimental techniques [16][17][18][19][20].…”

Pulsed-field ionization electron spectroscopy and conformation of copper-diammonia

“…It should be noted that our results for the neutral complex are different from the B3LYP/6-31G calculations by Satta et al 12 and the semiempirical selfconsistent-field ͑ZINDO͒ calculations by Doan and Kasai. 13 Both studies predicted a bent C 2v structure.…”