Table 3: Experimentally and theoretically simulated IR spectra (in cm−1) of the studied complexes. Assignment of theoretically calculated IR key modes for Co(II) and Cu(II) complexes in the gas phase. Excellent match between experimentally determined and theoretically computed IR modes in case of Ni and Zn complexes is obtained.

Complexυ (OH)υ (COO)υ (M-O)υ (M-N)

[Co(glu)(arg)(H2O)2]·H2O2513 (H-bonded H2O and O of COO of Gu)1684.8 (Ar)554.3463.6
35211740 (Gu)

[Cu(glu)((arg)]H2O3656 (caged H2O)1677.8 (Gu)537.6438.5
1709.9 (Ar)