Cadmium sulfide (CdS)-decorated, cross-linked melamine–formaldehyde polymer-based nanocomposite (MFP-CdS) has been synthesized. MFP-CdS is utilized here as a photoactive material for the photodegradation of six model organic dyes and their mixture in an aqueous medium in the presence of sunlight. The half-life values from the kinetic study of multiple dyes strongly support the importance of sunlight on the fast degradation of all six dyes compared to bulb light and control (dark) conditions. A comparative 1H NMR analysis of the dyes and their degraded products has been performed to support the breakdown of the aromatic framework of organic dyes using MFP-CdS in sunlight. The mechanisms involved in the photodegradation of dyes have been investigated based on radical trapping studies that support the significant involvement of superoxide radicals along with holes. Moreover, the dye removal efficiency using MFP-CdS from real industrial wastewater samples is evaluated via the external spiking of organic dyes and their mixture in unknown industrial effluents where they showed similar photodegradation results. Based on the high recyclability of MFP-CdS, these are used for multiple cycles.

A hybrid tris-bidentate neutral ligand (L) composed of a central 2,2'-bipyridine and two terminal triazolyl-pyridine chelating units connected by methylene spacers is employed to synthesize trinuclear triple-stranded side-by-side helicates of first-row transition-metal(II) ions. Three such new homometallic helicates LM(OTf) [ M = Cu (4); Ni (5); Co (6)], along with our recently reported helicates LFe(OTf) (1), LZn(OTf) (2), and LFeZn(OTf) (3) are taken into consideration for competitive formation and transmetalation studies. Single-crystal X-ray structures of LCu(OTf) (4) and LNi(OTf) (5) show the formation of trinuclear triple-stranded side-by-side helicates with alternating Λ and Δ chiralities at the metal ions as earlier observed in cases of LFe(OTf) (1), LZn(OTf) (2), and LFeZn(OTf) (3). ESI-FTICR mass spectrometry and UV-vis spectroscopy studies show that helicates LFe(OTf) (1), LZn(OTf) (2), LFeZn(OTf) (3), and LCo(OTf) (6) can easily be transmetalated to helicate LCu(OTf) (4) in the presence of Cu(OTf). On the other hand, only a trace amount of heterometallic helicate LNiCu(OTf) forms even after several days, when Cu(OTf) is added to a the solution of homometallic helicate LNi(OTf) (5). Further, we have demonstrated the formation of a heterometallic helicate LNiCo(OTf) (7) from a 1:1:1 reaction mixture of L, Ni(OTf), and Co(OTf), which can also be prepared from homometallic helicate LCo(OTf) (6) by transmetalation with Ni(OTf).

Formation of an ion-pair i.e. Fe and [Cl(HO)] coordination driven one dimensional (1D) smart supramolecular helical assembly of a new heteroditopic ligand was achieved. Moreover, thermo- and chemo-responsive transformation/disassembly/reassembly of the helical superstructure was also demonstrated.

We have reported a one-pot two step methodology for the synthesis of highly condensed pyrrolo[1,2-a][1,4]benzodiazepines by modified Pictet–Spengler reaction.

This investigation highlights the role of counter anion towards the formation of thermo-responsive supramolecular assemblies of pre-defined discrete molecular Cu(ii) macrocycles. A new heteroditopic ligand (L) composed of two terminal triazolyl-pyridine units and a central pyridine-2,6-carboxamide unit connected via ethylene spacers predominantly forms dinuclear Cu(ii) macrocycles [L2Cu2]X4 (X = ClO4-, NO3-, Cl-) in the presence of respective monoanion-based Cu2+ salts. In contrast, dianionic SO42--based Cu2+ salt produces a mixture of both dinuclear [L2Cu2(SO4)2] and mononuclear [LCu(SO4)] Cu(ii) macrocycles. Importantly, detailed molecular structure determinations revealed the presence of multiple secondary interactions of the different counter anions with the corresponding macrocycles. The field emission scanning electron microscopy (FESEM) studies confirmed the ability of the individual macrocycles to further assemble upon slow evaporation of the solvent. Morphologically pure rod, sphere, and sheet-like superstructures were obtained for ClO4-, NO3-, and Cl- monoanion-based macrocycles, respectively. In contrast, a mixture of linear ribbon and microflower-like assemblies were obtained for SO42--based macrocycles. Moreover, it was found that upon heating, the rod-like assembly of [L2Cu2](ClO4)4 was gradually transformed into nanoparticles through a microparticle formation, which regenerated the rod-like assembly upon standing at room temperature. This was established from the FESEM, atomic force microscopy (AFM), and dynamic light scattering (DLS) studies.