SAM-Na Ca(II) Zn(II) Pd(II) Au(III) Assignments 3381 3384 3445 3440 3376 ν(NH); NH2 1684 - - - 1703 ν(C=O); amido group 1355 1327 1315 1305 1405 νas(SO2); sulfonyl group 1148 1134 1094 1133 1153 νs(SO2); sulfonyl group - 595 621 635 - ν(M-O)   554 554 553     - - - - 543 ν(M-N)

Table 2: Distinguish Infrared spectral bands and their assignments of a free SAMNa ligand and their complexes.