Surface Layer‐by‐Layer Chemical Deposition Reaction for Nanosized Thin‐Film Formation of Metal Complexes of 2‐Mercaptonicotinic Acid

2‐Mercaptonicotinic acid [H 2 mna] reacted with Mn II , Co II , Ni II , Cu II , and Zn II by using a layer‐by‐layer chemical deposition technique; thin‐film nanosized metal–[Hmna] 2 complexes were formed. The metal complexes were synthesized by the alternative dipping of a glass substrate into the metal ion solution followed by the ligand solution. A molar stoichiometric ratio of 1:2 was characterized for all newly synthesized nanosized Mn II ‐, Co II ‐, Ni II ‐, Cu II ‐, and Zn II –2‐mercaptonicotinate complexes, as confirmed from analysis of the metal. Electron impact mass spectrometry (EIMS) of the collected particles from the thin‐film deposited Mn II [Hmna] 2 complex (as a selected example) indicates molecular ion peaks at m / z values of 155 and 363 amu for [H 2 mna] and Mn II [Hmna] 2 , respectively. The deposited thin films of the nanosized metal complexes were subjected to analysis and imaging by scanning electron microscopy (SEM) and were identified to give a range of detected particle sizes ≥20–130 nm. The five metal–[Hmna] 2 complexes were characterized by FTIR spectroscopy, and the ligand was found to bind to the metal through the carboxylic oxygen atom and the mercapto sulfur atom. The UV/Vis spectra of the deposited thin film materials and of the ethanol solutions of the complexes were recorded to identify the possibility of d–d transitions in all newly synthesized metal–[Hmna] 2 complexes. Thermal gravimetric analysis (TGA and DTG) was also used to identify the possible thermal degradation processes and to calculate some thermodynamic parameters.