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ABSTRACT Two novel Cr (III) and Ru (III) salen complexes based on {3,4‐Bis‐[(5‐chloro‐2‐hydroxy‐benzylidene)‐amino]‐phenyl}‐phenyl‐methanone ligand (CSAB) were synthesized. The complexes were characterized using various spectral and analytical methods. The catalytic performance of the CSAB complexes was investigated via a four‐component condensation reaction involving aromatic aldehydes, rhodamine, morpholine, and 5‐aminotetrazole under mild, environmentally friendly conditions. Different Lewis acids, bases, ionic liquid catalysts, solvents, and catalyst amounts were assessed to optimize the reaction parameters. Both catalyst systems demonstrated robust catalytic activity under strictly managed conditions, with the heterogeneous catalyst CSAB‐Ru showing superior efficacy compared to the homogeneous CSAB‐Cr catalyst. The study confirmed the catalytic capabilities of both complexes and evaluated their recyclability and reusability. The heterogeneous catalyst (CSAB‐Ru) could be reused seven times, whereas the homogeneous catalyst (CSAB‐Cr) could be recycled four times. Both complexes demonstrated strong catalytic activity and selectivity, resulting in high product yields. The study provides insights into the synthetic applications of novel CSAB complexes, highlighting their potential in organic transformations. It emphasizes their ease of use, safety, stability, component availability, quick reaction times, and high yields, making them promising for future industrial applications. [ABSTRACT FROM AUTHOR]

Two novel complexes were synthesized by the reaction of benzothiazol‐pyrimidin‐2‐ylidene ligand (BTP) with Pd (II) and Fe (III) ions. A variety of various spectral and analytical methods (infrared, 1H/NMR, 13C/NMR, electronic spectra, CHN analyses, mass spectra, thermogravimetric analysis, and magnetic susceptibility) were used to characterize the investigated BTP ligand and its complexes. Correlation of experimental results with density functional theory calculation proves that the geometry of BTP‐Fe complex is octahedral, whereas BTP‐Pd complex is square planner. The catalytic effectiveness of BTP complexes were tested for three‐component condensation process under moderate and environmentally friendly reaction conditions. Moreover, the effects of different Lewis acid, basic, and ionic liquid catalysts, as well as solvent and catalyst dose on the catalytic reaction were investigated. Both catalysts demonstrated strong catalytic capability in the carefully regulated ideal reaction circumstances. Heterogeneous catalyst BTP‐Pd exhibited superior catalytic performance compared to homogeneous catalyst BTP‐Fe. All products were obtained in high TOF (turnover frequency) numbers in the presence of these catalysts, which indicate the high efficiency of these catalysts in the synthesis of dihydro‐7H‐5‐thia‐hexaaza‐s‐indacen‐6‐one derivatives. Moreover, the two catalysts' recycling and reusability in reactions were also investigated. Heterogeneous BTP‐Pd catalyst could be reused up to seven times with high efficiency, but the homogeneous catalyst (BTP‐Fe) could only be recycled up to four times. Furthermore, the mechanism of catalytic reaction was suggested and supported by DFT calculation. The simplicity, safety, stability, use of commercially available catalysts, quick reaction times, and excellent yields make it promising for future industrial use. [ABSTRACT FROM AUTHOR]

In this study, the focus was on synthesizing metal chelates of Fe(III), Ni(II), and Pd(II) using thiazole‐guanidine derivatives. Various spectral and analytical methods were employed to elucidate the structural characteristics and determine the molecular formulae of these metal chelates, including infrared (IR(, 1H‐NMR and 13C‐NMR, ultraviolet–visible (UV–vis), CHN, XRD data, mass spectrometry, thermal conduction, and measures of magnetism, were used to clarify the structures of these compounds. The optimized molecular structures have been scrutinized by the DFT method. Correlation between all spectroscopic methods and DFT calculation revealed an octahedral‐coordinating environment surrounding the Fe3+ ion, [Fe (BTG)2(NO3)2].NO3.2H2O and Ni2+, [Ni (BTG)2(NO3)2].H2O cation and distorted square planner surrounding Pd2+, [Pd (BTG) (COOCH3)2].2H2O cation. The examination of the stability and stoichiometry of complexes in solution using conventional techniques has been incorporated into the investigation's scope. Under mild reaction conditions, the green technique was employed to carry out a condensation reaction for aromatic aldehyde, rhodanine, pipredine, and 5‐aminotetrazol to generate derivatives of 6‐piperidin‐dihydro‐thia‐hexaaza‐s‐indacene derivatives. In comparison to our new complexes, all reaction conditions were optimized for those variable Lewis acid catalysts. In general, tests conducted under high yield, speedy, and environmentally friendly solvent (H2O/EtOH) conditions, the BTGPd catalyst showed superiority over others. Additionally, the hetero‐catalyst recovery proved successful and could be employed with the same efficiency up to six times before the efficiency started to decrease. The effectiveness of this catalytic procedure was validated through a thorough examination using density functional theory (DFT). The DFT analysis showcased the distinctive characteristics of this complex and proposed logical mechanisms that elucidated the crucial physical parameters responsible for the superior catalytic performance of the Pd(II) complex. [ABSTRACT FROM AUTHOR]