The first reported syntheses and characterisation of alkali metal trifluoronickelate(II) monohydrates,MNiF3 · H2O (M = NH4, Na or K)

Summary Ni(acac)₂ · (H₂O)₂ (1 mol) and alkali metal fluorides (4 mols), MF (M=NH₄, Na or K), react with an excess of 40% HF on a steam-bath. The product upon treatment with water gives light green crystalline alkali metal trifluoronickelate(II) monohydrate, MNiF₃ · H₂O in a high yield. Chemical analyses, pyrolysis at 120 °C, i.r. spectroscopic, and cryomagnetic (300–80 K) data have been used to characterise, and establish the identity of the compounds. While NH₄NiF₃ · H₂O behaves as a normal octahedral nickel(II) compound, NaNiF₃ · H₂O is ferromagnetic with Curie point 145 K, KNiF₃ · H₂O behaves antiferromagnetically; its Neel point is 230 K.     

On the melting temperatures of 3,6-diamino-9H-carbazole and 3,6-dinitro-9H-carbazole

This article records the diversely reported melting temperatures of 3,6-diamino-9H-carbazole (DAC) and 3,6-dinitro-9H-carbazole (DNC), and reports a reinvestigation on their melting phenomena, and associated specific observations. A rationalization of these reports has been attempted on the basis of IR spectroscopic, X-ray diffraction, thermal response, solubility behavior, and differential scanning calorimetric data on DAC and DNC. The data indicate that an exothermic inter-molecular deaminative self-condensation involving N₉H and NH₂ sets in prior to melting of DAC, which obscures the actual melting process. An extrapolated onset melting temperature of 241.0 °C and a peak temperature of 296.5 °C at zero heating rate have been assigned for DAC from DSC measurements. A possible structure of the polymeric self-condensation product is also presented. For DNC, a peak melting temperature of 296.5 ± 1.8 °C, but no onset melting temperature could be assigned.     

Synthesis,physico-chemical and antimicrobial studies on acetylferrocenyl hydrazone derivatives of dichlorobis(cyclopentadienyl)hafnium(IV)

The reactions of Cp₂>HfCl₂> with hydrazones (LH) derived from acetylferrocene and aromatic acid hydrazides (benzoic, 2-chlorobenzoic, 3-nitrobenzoic and 4-toluic) in various stoichiometric ratios have been studied and the complexes of the types [Cp₂>Hf(L)Cl] and [CpHf(L)₃>] were obtained. Tentative structural conclusions are drawn for the reaction products based upon elemental analyses, electrical conductance, magnetic moment and spectral data (u.v.–vis, i.r., ¹>H-n.m.r. and ¹³>C-n.m.r.). Studies were conducted to assess the growth-inhibiting potential of the complexes synthesized, and the ligands, against various fungal and bacterial strains.     

Effect of back electrode on photovoltaic properties of crystal-violet-dye-doped solid-state thin film

Recently, organic/polymeric materials are being widely used to develop photovoltaic devices. In our earlier work, we have studied the photovoltaic property of crystal violet in solid-state photoelectrochemical cell (PEC), but the power conversion efficiency is quite low. In this work, we have used aluminium-coated mylar as a back electrode to enhance the power conversion efficiency. Because of the insertion of a reflecting back electrode, the charge carriers are confined in the active layer which enhances the efficiency from 0.144% to 0.670%. Thin film polymer PEC has been prepared by using optically active crystal violet dye. The dye was dispersed in polyvinyl alcohol used as an inert polymer binder and polyethylene oxide complexed with lithium perchlorate (LiClO₄) ion salt as a solid electrolyte with ethylene carbonate and propylene carbonate as plasticisers. With this blend, two cells have been prepared. In one cell, this blend is sandwiched between indium-tin-oxide-coated glass plate and aluminium plate whereas the modification of the cell is done using highly polished aluminium-coated mylar sheet in place of Al electrode. Dark I–V characteristics are measured and compared for these cells. Improvement of photovoltaic parameters has been observed in the case of polished mylar electrode.     

Rapid assembly of the functionalized tricyclic core of umbellactal through domino metathesis involving ROM-RCM of a norbornene derivative

A novel approach to the construction of the functionalized core structure of the anticancer diterpene umbellactal is described using a domino metathesis protocol involving ROM-RCM of an appropriately constructed norbornene derivative.     

A production–recycling–inventory system with imprecise holding costs

This paper presents an optimal control recycling production inventory system in fuzzy environment. The used items are bought back and then either put on recycling or disposal. Recycled products can be used for the new products which are sold again. Here, the rate of production, recycling and disposal are assumed to be function of time and considered as control variables. The demand inversely depends on the selling price. Again selling price is serviceable stock dependent. The holding costs (for serviceable and non-serviceable items) are fuzzy variables. At first we define the expected values of fuzzy variable, then the system is transferred to the fuzzy expected value model. In this paper, an optimal control approach is proposed to optimize the production, recycling and disposal strategy with respect so that expected value of total profit is maximum. The optimum results are presented both in tabular form and graphically.     

Degradation of Safranine T dye-based photo electrochemical organic photovoltaic devices

In this work, we studied the degradation of different photovoltaic parameters of Safranine T (ST) dye-doped organic photo electrochemical cell (PEC). Different photovoltaic parameters were measured for as-prepared device. The same measurement was repeated with time at 24-h regular interval for five successive days. During the measurement, the devices were unencapsulated and kept in an open environment. The photovoltaic parameters degraded up to 90% of its initial value. Along with moisture, humidity was the main reason for the degradation considered to be the reduction of work function difference of two electrodes in contact with organic blend.     

Ligand exchange synthesis of organometallic Rh nanoparticles and application in explosive sensing

Alkyne {phenyl acetylene (PA) and 9-ethynylphenanthrene (EPT)}-ligated Rh nanoparticles (1 and 2, respectively) with mean diameter of 1.5 ± 0.2 nm were synthesized via a facile and high-yield biphasic ligand exchange protocol using similar sized ethylene glycol (EG)-stabilized Rh nanoparticles as precursors (EG:Rh). The synthesized organometallic Rh nanoparticles were convincingly characterized using several spectroscopic and microscopic techniques, e.g., Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR), optical absorption spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscope (TEM). We propose that the syntheses mechanism relies on catalytic acetylenic (≡C–H, carbon–hydrogen) bond breaking by EG:Rh followed by strong metal–carbon bond formation with a vinyldiene (>C═C═M) motif. The obtained 1 and 2 showed luminescence property, which arises from ligand structure through intraparticle conjugation. Electron-rich phenanthrene-ligated Rh nanoparticles (2) showed good sensing performance for detection of electron deficient nitro-aromatic explosive molecules (NA) in solution phase through luminescence quenching method.