An easy-to-prepare chemosensor, (E)-1-(phthalazine-4-yl)-2-(1-(pyridine-2-yl)ethylidene) hydrazine (3), structurally characterized by single X-ray crystallography, is developed for the selective and sensitive detection of Co(2+) in aqueous media. Chemosensor 3 shows both absorption and fluorescence responses to Co(2+) by forming a 1:1 complex (among the surveyed metal ions) with a detection limit down to 50 nM. It can also be used as a 'naked-eye' sensor due to the outstanding visible and emission color changes from yellow to red and blue to orange, respectively.

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A new phthalazine based chemosensor was developed for the highly selective and sensitive detection of Co(2+) in the mixed solvent system, CH3CN-H2O (1 : 1, v/v). In the presence of Co(2+), the colour of the solution changed from yellow to green; the absorption maxima of was red-shifted from 383 nm to 435 nm, and the fluorescence of at 550 nm was significantly enhanced. The sensor showed a detection limit down to 25 nM by forming a complex species with Co(2+) in 1 : 1 stoichiometry. Furthermore, by means of confocal laser scanning microscopy experiments, it has demonstrated that it can be used as a fluorescent probe for monitoring Co(2+) in living cells.

Chiral [VO(salen)] complexes (R,R)‐7 and (R,R)‐8 were synthesised by ligand replacement from [VO(acac)2] with the resolved (1R,2R)‐cyclohexyl ligands 3,3′‐[(1R,2R)‐1,2‐cyclohexane‐diylbis(nitrilomethylidyne)]bis‐4‐phenanthrenol [(R,R)‐3] and 3,3′‐[(1R,2R)‐1,2‐cyclohexanediylbis(nitrilomethylidyne)]bisbenz[a]anthracen‐1‐ol [(R,R)‐4], respectively. Similarly, complexes (R)‐9 and (R)‐10 were synthesised using the (R)‐binaphthyl ligands 3,3′‐[(1R)‐(1,1′‐binaphthalene)‐2,2′‐diylbis(nitrilomethylidyne)]bis‐4‐phenanthrenol [(R)‐5] and 3,3′‐[(1R)‐(1,1′‐binaphthalene)‐2,2′‐diylbis(nitrilomethylidyne)]bis‐benz[a]anthracen‐1‐ol [(R)‐6], respectively. These complexes were characterised by IR spectroscopy, ESI‐TOF‐MS, electronic absorption spectroscopy and circular dichroism (CD). Single crystal X‐ray analysis of (R,R)‐7 and (R,R)‐8 revealed distorted square pyramidal geometries and a 1:1 ratio of diastereomeric M and P helical conformers. Solution CD studies in THF combined with DFT calculations indicate that the M conformer dominates in solution for (R,R)‐7. Preliminary catalytic oxidation of thioanisole with H2O2 and 1 % [VO(salen)] showed good selectivity for sulfoxides over sulfones but low enantioselectivities (8 to 33 %) which are solvent dependent but insensitive to the catalyst used.

Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by (1)H and (13)C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.