Novel Gallium(III), Germanium(IV), and Hafnium(IV) Folate Complexes and Their Spectroscopic, Thermal Decomposition, Morphological, and Biological Characteristics

Abstract

In this study, we describe novel gallium(III), germanium(IV), and hafnium(IV) folate complexes, including their synthesis and analyses. The synthesized folate complexes were also subject to thermal analysis (TGA) to better examine their thermal degradation and kinetic properties. The folate complexes had high stability and were nonspontaneous. The Coats–Redfern and Horowitz–Metzger equations were used to determine thermodynamic parameters and describe the kinetic properties. These complexes were synthesized through the chemical interactions in neutralized media between the folic acid drug ligand (FAH2) with GaCl3, GeCl4, and HfCl4 metal salts at 1 : 2 (metal : ligand) molar ratio. The conductance measurements have low values due to their nonelectrolytic behavior. The X-ray powder diffraction solid powder pattern revealed a semicrystalline nature. In vitro, we screened the synthesized folate chelates for antibacterial and antifungal activities. The inhibition of four bacterial and two fungi pathogens (E. coli, B. subtilis, P. aeruginosa, S. aureus, A. flavus, and Candida albicans) was improved using a folic acid drug relative to the control drug.

Folic acid and sodium folate salts: Thermal behavior and spectroscopic (IR, Raman, and solid-state 13C NMR) characterization

“…The nanoengineering of smart delivery systems includes plenty of organic and inorganic nanoparticles as well as FA-drug conjugates [16][17][18]. In addition, FA forms complexes with a series of metal cations by coordination with its Glu or PT moieties [19][20][21][22][23][24]. Such complexes can be used as antimicrobial agent [19,23], anticancer-drug [24] or in the treatment of diabetes [22].…”

“…In addition, FA forms complexes with a series of metal cations by coordination with its Glu or PT moieties [19][20][21][22][23][24]. Such complexes can be used as antimicrobial agent [19,23], anticancer-drug [24] or in the treatment of diabetes [22]. In nanomaterial and nanotechnology science, FA has been used as precursor of supramolecular structures (liquid crystals and gels) [25][26][27] and nitrogen doped carbonaceous materials [27,28].…”

“…It is significantly increased in pH values above 5 [37], for which the dianion (HFol 2-) and trianion (Fol 3-) are then dominant species [2] (Figure 1b). Therefore, folate anionic species which studies are often neglected must nevertheless be considered because of: (i) at physiological pH value for which HFol 2is predominant [38][39][40]; (ii) the preparation of many materials and compounds (or the handle of FA in some studies) are performed at pH values above 5 [7,14,[22][23][24][31][32][33][34]; and (iii) the supramolecules assembled by FA are pH-responsiveness [25][26][27]. Braga et al [41] prepared dianionic folates salts (Li, Na and Ca) and showed their higher dissolution rate as well as higher thermal stability than FA.…”