Synthesis and EPR/UV/Vis‐NIR Spectroelectrochemical Investigation of a Persistent Phosphanyl Radical Dication

The reaction of the bis(imidazoliumyl)‐substituted P^I cation [(2‐Im^Dipp)P(4‐Im^Dipp)]⁺ ( 10 ⁺) (2‐Im=imidazolium‐2‐yl; 4‐Im=imidazolium‐4‐yl; Dipp=2,6‐di‐isopropylphenyl) with trifluoromethanesulfonic acid (HOTf) or methyl trifluoromethylsulfonate (MeOTf) yields the corresponding protonated [(2‐Im^Dipp)PH(4‐Im^Dipp)]²⁺ ( 11 ²⁺) and methylated [(2‐Im^Dipp)PMe(4‐Im^Dipp)]²⁺ ( 12 ²⁺) dications, respectively. EPR/UV/Vis‐NIR spectroelectrochemical investigation of the low‐coordinated P^I cation 10 ⁺ predicted a stable and “bottleable” P‐centered radical dication [(2‐Im^Dipp)P(4‐Im^Dipp)]^2+. ( 13 ^2+.). The reaction of 10 ⁺ with the nitrosyl salt NO[OTf] yields the persistent phosphanyl radical dication 13 ^2+. as triflate salt in crystalline form. Quantum chemical investigation revealed an exceptional high spin density at the P atom.     

Copper-catalyzed arylation of tetrazole-5-thiones upon convection heating and microwave activation conditions

The arylation of 1-phenyltetrazole-5-thione using a series of iodobenzene derivatives in the presence of cuprous chloride and a ligand such as ethylenediamine. It was shown that the use of microwave activation permitted shortening of the reaction time, increasing yields and simplification of the reaction products isolation.     

Nonempirical quantum-chemical calculation of the electric field gradient at the <Superscript>51</Superscript>V nucleus sites in alkali metavanadates

The electric-field gradient tensor at the vanadium nucleus site was calculated ab initio within a cluster model for chained vanadates XVO₃ (X=Li, Na, K). A comparison with experiment showed that it suffices to consider only small (VO₄)^3? and (V₃O₁₀)^5? clusters in crystals of this type. The calculation scheme stability with respect to increasing cluster size was analyzed.     

New method for the determination of the quantum yields in the photo-isomerization of photochromic epoxydiarylindanones

A method for the determination of the quantum yield in the formation of the unstable photoinduced form of 2, 3-epoxy-2, 3-diphenylindanone based on the reaction with tetracyanoethylene is proposed. The products of 1,3-dipolar addition of tetracyanoethylene to the photoinduced forms of the investigated compounds were isolated and characterized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 167–170, February, 1984.     

Notes on the nonrelativistic binding energy for neutral atoms

An analytical expression is obtained for the binding energy of a neutral atom within the statistical theory $\text{E = ? 0.76874 Z}{}^{\mathrm{<mtext>7</mtext><mtext>3</mtext>}}\text{+ 0.5 Z}{}^2\text{? 0.2699 Z}{}^{\mathrm{<mtext>5</mtext><mtext>3</mtext>}}$, which prefectly reproduces SCF binding energy for Z > 20. The oscillations of energy are discussed.     

Elektronen-mikroskopische Untersuchung der Strukturbildung in Polyvinylalkoholl?sungen und -gelen

Ohne Zusammenfassung