Synthesis, structural characterization and antimicrobial activities of diorganotin(IV) complexes with azo-imino carboxylic acid ligand: Crystal structure and topological study of a doubly phenoxide-bridged dimeric dimethyltin(IV) complex appended with free carboxylic acid groups

Novel Organotin(IV) Complexes of 2-[4-Hydroxy-3-((2-hydroxyethylimino)methyl)phenylazo]benzoic Acid: Synthesis, Structure, Noncovalent Interactions and In Vitro Antibacterial Activity

“…The Sn-C band of the complex 1 is doublet in nature (579 and 538 cm −1 ), which means that the Sn-C bonds are non-linear and the Sn-O bond is sharp at 492 cm −1 . For complexes 2 and 3, these are assigned in a similar way (for 2: 598, 585 cm −1 and 507 cm −1 ; for 3: 595, 581 cm −1 and 538 cm −1 ) to Sn-C and Sn-O bonds, respectively [10,21,30]. 13 C and 119 Sn) NMR-Spectroscopy…”

“…The asymmetric (ν (COO)asy ) and symmetric (ν (COO)sy ) stretching frequencies of the carboxylate group in the ligand appear at 1698 cm −1 and 1385 cm −1 , respectively. As a result of COOcoordination to Sn(IV), these bands shift to the frequency range at 1630-1654 cm −1 for asymmetric -COO and 1372-1394 cm −1 for symmetric-COO [10,[15][16][17]21,30]. The difference between the asymmetric and symmetric frequencies, i.e., ∆ν( ν(COO)asy − ν (COO)sym ) is 282, 248 and 236 cm −1 respectively for the complexes 1, 2 and 3, which are greater than 200 cm −1 , indicating that the carboxylate group coordinates to Sn(IV) in monodentate mode in each complex [15,16].…”

“…Based on the Sn-alkyl protons signals, the complexes could be distinguished from the uncoordinated ligand, as well as from one another. The complex 1 has Sn-methyl groups, which is detected as a singlet peak at 0.61 ppm [21]; the complex 2 has Sn-Bu 3 , which results in two distinct peaks as a triplet peak at 0.89 ppm and two multiplets in the range of 1.25-1.66 ppm for the methyl and the three methylene protons, respectively; similarly, the complex 3 with Sn-Bu 2 shows two multiplet peaks in the range of 0.91-1.46 ppm for tin-butyl protons [10,21].…”

“…Moreover, the geometry and coordination number of the complex 2 can be predicted from its carbon satellites (Figure S9) by determining n J ( 119 Sn-13 C) coupling constant values [15,16,21]. The complex 2 has 352.6 Hz, 19.9 Hz and 64.4 Hz coupling constant for 1 J ( 119 Sn-13 C), 2 J ( 119 Sn-13 C) and 3 J ( 119 Sn-13 C) coupling satellites, respectively, indicating that the complex has four coordinate quasi tetrahedral geometry around tin centres [15,16,21] in the solution state. It was further confirmed by its 119 Sn NMR spectral signal [15], which is found at +115.98 ppm (Figure 3).…”

“…Nevertheless, coordinated ligands play a vital role in the structural variety of organotin(IV) compounds. Ligands bearing carboxylate/hydroxo groups with Schiff base imine, azo, or azo-imine functionalities have been extensively investigated [13][14][15][16][17] for their stereochemical motifs and biological applications [18][19][20][21][22][23][24][25].…”