Preparation of 4,5-dimethylenecyclohexane-1,2-diamines by the [4+2]-cyclization of 2,3-dimethylene-1,4-bis-(dipropylboryl)butane with 1,2-diimines

N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2198–2199, September, 1992.     

Multi-walled carbon nanotubes-ferroelectric liquid crystal nanocomposites: effect of cell thickness and dopant concentration on electro-optic and dielectric behaviour

Nanocomposites comprise functionalised multi-walled carbon nanotubes (0.00 wt%, 0.05 wt% and 0.07 wt%) and ferroelectric liquid crystals (FLCs) have been studied in the 5-μm- and 12-μm-thickness cells. Effect of anchoring energy and dopant concentration on the mesomorphic, electro-optic and dielectric behaviour of FLC has been explored. Fast switching time and increase in permittivity of non-doped FLCs and resulting nanocomposites as a function of increased cell thickness (from 5 to 12 μm) can be attributed to the change in the anchoring energy and direct current (DC) conductivity of the non-doped and doped systems. π–π stacking between carbon nanotubes and FLC layers give rise to the spontaneous polarisation of nanocomposites. Effect of cell thickness and anchoring energy on bistability are also discussed.     

Synthesis of 3,5-dimethyl-1-boraadamantane and its transformation into 3,5-dimethyl-1-azaadamantane

The first synthesis of 3,5-dimethyl-1-boraadamantane from its easily available tetrahydrofuran adduct comprised sequential treatment with BuLi, AcCl, (Cy₂BH)₂ and heating. The compound was converted into its electronic ‘antagonist’, namely, 3,5-dimethyl-1-azaadamantane.

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Spectral study of complexation ofcis,cis-1,3,5-tri[2-(diphenylphosphinyl)ethylamino]cyclohexane with copper(ii) and cobalt(ii) ions

The complexation ofcis,cis-1,3,5-tri[2-(diphenylphosphinyl)ethylamino]cyclohexane (L¹) with Cu²⁺ and Co²⁺ cations has been studied in different solvents by means of UV-Vis, ESR, and IR spectroscopy. It has been shown that in the CuL¹ complex the metal ion is pentacoordinated by three nitrogen atoms and two phosphinyl groups of the ligand and has a tetragonal-pyramidal environment. The conformation of the coordination polyhedron for the CuL¹ complex depends on the solvent. In the CoL¹ complex, as well as in the CoL² complex, where L² is 1,4,7-tris(2-diphenylphosphinylethyl)-1,4,7-triazacyclononane, the Co²⁺ ion has an octahedral environment and is bound to all donor atoms of the ligands.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1199–1202, July, 1993.The authors are grateful to A. G. Matveeva and Yu. M. Polikarpov for the fruitful discussions.     

Synthesis and structures of five-coordinate bis-o-iminobenzosemiquinone complexes M(ISQ-R)2X (X = Cl, Br, I, or SCN; M = CoIII, FeIII, or MnIII)

New five-coordinate complexes Co(ISQ-Prⁱ)₂Cl, Co(ISQ-Me)₂Cl, Co(ISQ-Me)₂I, Co(ISQ-Me)₂(SCN), Mn(ISQ-Prⁱ)₂Cl, and Fe(ISQ-Me)₂Br (ISQ-Prⁱ and ISQ-Me are the 4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-and 4,6-di-tert-butyl-N-(2,6-dimethylphenyl)-o-iminobenzosemiquinone radical anions, respectively) were synthesized. The complexes were characterized by UV-Vis and IR spectroscopy and magnetochemistry. The molecular structures of the Fe(ISQ-Me)₂Br and Mn(ISQ-Prⁱ)₂Cl complexes were established by X-ray diffraction. The singlet ground state (S = 0) of the cobalt complexes is caused by antiferromagnetic coupling between the unpaired electrons of the radical ligands (S = 1/2) through the fully occupied atomic orbitals of low-spin cobalt(III) (d⁶, S = 0). The effective magnetic moments of the complexes at 10 K are 0.18 μ_B for Co(ISQ-Prⁱ)₂Cl and 0.16 μ_B for Co(ISQ-Me)₂I. The ground state of the manganese complex is triplet (S = 1). Two unpaired electrons of the o-iminobenzosemiquinone ligands are strongly antiferromagnetically coupled with two of four unpaired electrons of high-spin manganese(III) (d⁴, S = 2). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 43–51, January, 2006.     

Investigation of radical pairs produced upon pulse action of elastic waves on the 3,6-di-tert-butylcatechol-3,6-di-tert-butyl-o-benzoquinone-sulfur system

The pulse action of elastic waves on polycrystalline mixtures of 3,6-di-tert-butylcatechol and 3,6-di-tert-butyl-o-benzoquinone produces radical pairs stable at room temperature, and the addition of polycrystalline sulfur considerably increases their yield. The dependences of formation and decay rates of paramagnetic centers on the composition of the mixture were studied. The threshold character of formation of paramagnetic centers at various powers of elastic wave pulse was established.Translated fromIzvestiya Akademii Nauk. Seriva Khimicheskaya, No. 4, pp. 864–868, April, 1996.