Narrow Results

The paramagnetic complexes (FPc)(Me)Rh^- (4) and (FPc)(PMe₃)(Me)Rh^- (10) have been prepared by reducing (FPc)(Me)Rh (1) and (FPc)(PMe₃)(Me)Rh (2) with NaBH₄ in methanol-d₄ [FPc^2- = dianion of 1,4,8,11,15,18,22,25-octakis(trifluoromethyl)phthalocyanine]. Compounds 4 and 10 are further reduced by NaBH₄ to complexes, which are assigned to (DFPc)(Me)Rh^- (5) and (DFPc)(PMe₃)(Me)Rh^- (11), respectively. Based on the ¹H NMR spectra of these complexes, 4 and 10 are assigned to the Rh(III) complexes of the singly reduced radical anion FPc^·3-, while 5 and 11 are assigned to the Rh(III) complexes of the doubly reduced, antiaromatic anion DFPc^3-, which has the deuteron bonded to one of its meso nitrogens. As expected, the antiaromatic complexes 5 and 11 are not stable. At -40 °C, 5 was transformed successively into three aromatic compounds, the first of which was assigned to the ring-contracted α,β,γ-triazatetrabenzocorrole complex (TBC)(Me)Rh^- [TBC^3- = trianion of 3,6,10,13,17,20,24,27-octakis(trifluoromethyl)-α,β,γ-triazatetrabenzocorrole]. Cyclic voltammetry of 1 and 2 was also carried out. Two reversible one-electron reduction waves were observed for both 1 and 2.

The new ceramic compounds type BaREBiO₄ (where RE = Sm and Nd) have been reported for the first time. The sample was prepared by solid-state reaction technique. The orthorhombic crystallization with a = 6.429(4) Å, b = 6.536(5) Å, c = 8.648(4) Å for BaSmBiO₄ and a = 6.485(3) Å, b = 6.561(4) Å, c = 8.686(4) Å for BaNdBiO₄ was studied from powder X-ray diffraction studies. The semiconducting nature of the compounds was observed with the energy gap measurement from diffused reflectance spectroscopy (DRS) studies. The paramagnetic nature of the compounds at room temperature and low temperature conditions was identified by magnetization measurements as a function of magnetic fields and temperature. The effective magnetic moment of the samples was found to be 2.126 μ_B and 4.272 μ_B.

Nanoparticle dilute magnetic semiconductors (DMS) are becoming increasingly important due to their possible applications in spintronics, an emerging field where the conduction process in the materials is a spin-based process. Nanoparticles of Mn-doped ZnO (DMS) material with general formula Zn${}_{1-x}$Mn_xO ($x=0.05,0.15,0.2$) were prepared by opting single stage combustion synthesis process. The samples characterized, exhibited formation of monophasic nanoparticles of the sample with average particle size ranging between 17 nm to 23 nm. The calculations of energy bandgap made from UV absorption spectra showed variation of the bandgap from 2.18 eV to 2.32 eV. The magnetic measurements (VSM) made on the samples confirmed formation of a single diamagnetic (Zn${}_{0.95}$Mn${}_{0.05}\mathrm{\text{O}}$) and two namely (Zn${}_{0.85}$Mn${}_{0.15}\mathrm{\text{O}}$) (Zn${}_{0.8}$Mn${}_{0.2}\text{O}$) paramagnetic samples. It is interesting to see that all the three magnetic profiles exhibit hysteresis type behavior both in diamagnetic form and paramagnetic form. The resistivity of the samples was of the order of 10${}^{10}$ Ohm-cm ($\mathrm{\Omega }$-cm) at lower temperatures. Temperature-dependent resistivity curves exhibited peaking behavior for all the three samples which is very interesting. Temperature-dependent thermo-power profiles give an indication of $n$-type semiconductor behavior with significantly deep and broad minima around 100${}^{\circ }\mathrm{\text{C}}$ which becomes sharper for sample with higher Mn concentration.