Reactivity of α-germyl nitriles with acetonitrile: Synthesis, structures, and generation of Ph3Ge[NHC(CH3)CHCN] and 2,6-dimethyl-4-(triphenylgermylamino)pyrimidine from Ph3GeCH2CN

The formation of 3-aminocrotononitrile and 4-amino-2,6-dimethylaminopyrimidine has been observed during the course of the hydrogermolysis reaction between a germanium amide and a germanium hydride, either as the free amines or bound to germanium as ligands consisting of their conjugate bases. These species arise from the dimerization or trimerization of acetonitrile, and have only been detected when germanium amides having substantial steric bulk at the germanium center are employed in the reaction. The isolation of germanium-bound 3-aminocrotononitrile compounds suggests that α-germyl nitrile species R₃GeCH₂CN that result from the reaction of the germanium amides R₃GeNMe₂ with CH₃CN solvent also can further react with CH₃CN to generate the 3-aminocrotononitrile and 4-amido-2,6-dimethylaminopyrimidine species. The two germanes Ph₃Ge[NHC(CH₃)CHCN] and 2,6-dimethyl-4-(triphenylgermylamino)pyrimidine have been prepared and structurally characterized, and the conversion of Ph₃GeCH₂CN to Ph₃Ge[NHC(CH₃)CHCN] and 2,6-dimethylamino-4-(triphenylgermylamino)pyrimidine as well as the conversion of Ph₃Ge[NHC(CH₃)CHCN] to 2,6-dimethyl-4-(triphenylgermylamino)pyrimidine in acetonitrile solvent has been observed using ¹H NMR spectroscopy.     

Flow-injection spectrophotometric determination of novalgin in pharmaceuticals using micellar medium.

A sensitive flow-injection (FI) procedure with spectrophotometric detection in a micellar medium is proposed for the determination of novalgin. The method is based on the instantaneous formation of a red-orange product (lambda(max) = 510 nm) after the reaction between novalgin and p-dimethylaminocinnamaldehyde (p-DAC) in a dilute acid medium. The sensitivity of this reaction was increased by a factor of 5.6 in the presence of sodium dodecyl sulfate (SDS). Experimental design methodologies were used to optimize the chemical and FI variables. The calibration curve was linear in the range of 1.45 x 10(-6) to 2.90 x 10(-5) mol L(-1) with an excellent correlation coefficient (r = 0.9999). The detection limit was 1.31 x 10(-7) mol L(-1) (n = 20, RSD = 2.0%). No interferences were observed from the common excipients. The results obtained by the proposed method were favorably compared with those given by the iodometric reference method at 95% confidence level.     

Formation of [Bi11]3−, A Homoatomic,Polycyclic Bismuth Polyanion,by Pyridine‐Assisted Decomposition of [GaBi3]2−

Until now, polycyclic bismuth polyanions have not been known—thus discriminating bismuth from its lighter congeners. However, the synthesis of [K([2.2.2]crypt)]₃(Bi₁₁)?2 py?tol, allows us to present the first structurally characterized homoatomic, polycyclic bismuth polyanion, which exhibits the [P₁₁]^3? “ufosan” structure. It was obtained upon treatment of [K([2.2.2]crypt)]₂(GaBi₃)?en with the solvent pyridine. The binary Zintl anion [GaBi₃]^2? decomposes under oxidative coupling of pyridine molecules and release of H₂ to form the title compound. The unprecedented reaction, its products and by‐products were investigated by means of spectroscopy, spectrometry, and DFT studies. All findings reveal the specific reaction conditions to be crucial for the formation of the [Bi₁₁]^3? ion—and indicate the possibility of the generation and isolation of further, large bismuth polyanions.     

Electronic parameters of cation complexation by calixarene ionophores

The Gibbs energy of extraction experiments of ionophoric calixarenes with alkali metals from the literature have been correlated with electronic parameters of their “monomeric” structures calculated by AM1, PM3 and PM7 algorithms: energies of molecular orbitals and charge densities of oxygen and nitrogen atoms. We observed general correlations of the extraction constants with the charge on the carbonyl oxygen and specific correlations with MO-energy using the covalent term of the Klopman–Salem equation. The correlations for calixarenes with 5 and 6 phenolic units were very poor, and we attributed to the structural flexibility, which allow different optimized conformations for metal binding.     

Evidence for the quantum birth of our universe

We present evidence for a nonsingular origin of the Universe with intial conditions determined by quantum physics and relativistic gravity. In particular, we establish that the present temperature of the microwave background and the present density of the Universe agree well with our predictions from these intial conditions, after evolution to the present age using the Einstein-Friedmann equation. Remarkably, the quantum origin for the Universe naturally allows its evolution at exactly the critical density. We also discuss the consequences of these results to some fundamental aspects of quantum physics in the early Universe.     

Measurement of the decay of light-induced gratings for characterization of QW heterostructures of type I and II

Using a non-resonant transient grating technique the mobility and recombination lifetime of free carriers in type I and type II QW heterostructures is measured. For the lattice-matched type II Ca_xSr_1−xF₂/GaAs structures the diffusion coefficient as well as the diffraction efficiency is found to be affected by carrier separation into different layers. For GaAs/GaAlAs superlattices a strong influence of the barrier parameters on the inplane diffusion of heavy holes is observed.