Protonation of triethyl (2-pyridylimido)phosphates

Protonation of triethyl (2-pyridylimido)phosphates has been studied by potentiometric titration in nitromethane, IR and NMR spectroscopy, and X-ray structure analysis. The substances studied are protonated in one step at the N-atom of the pyridine ring. The protonated cations may be represented, according to the X-ray data, as a resonance of two structures: pyridinium and pyridoniminium; the contribution of the latter probably being considerable. Changes in spectral parameters of POEt groups upon protonation of pyridylimidophosphates (PIP) have been noted.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No 1, pp. 88–91, January, 1993.     

2,4-Bis(diphenylphosphorylmethyl)mesitylene: Synthesis and complex formation with lanthanide nitrates. Crystal structure of [Nd(L1(NO3)3 · Me2CO]

A new bisphosphoryl ligand, 2,4-bis(diphenylphosphorylmethyl)mesitylene (L¹), has been synthesized. Upon the interaction of L¹ with lanthanide nitrates, stable mononuclear chelates [Ln(L¹) _n (NO₃)₃] (Ln = Ce(III), Nd(III), Er(III); n = 1, 2) were obtained. The structure of the complexes in solid state and in solution was studied by vibrational (IR and Raman) spectroscopy, X-ray diffraction, and conformational (molecular mechanics) analysis.     

Generation of picosecond pulses in solid-state lasers using new active media

Results are reported of investigations aimed at generating nanosecond radiation pulses in solid-state lasers using new active media having broad gain lines. Passive mode locking is accomplished for the first time in a BeLa:Nd³⁺ laser at a wavelength 1.354 m, and in a YAG:Nd³⁺ laser on a 1.32–m transition. The free lasing and mode-locking regimes were investigated in an alexandrite (BeAl²O₄:Cr³⁺) laser in the 0.72–0.78–m range and in a synchronously pumped laser on F 2- centers in LiF in the 1.12–1.24–m region. The features of nonlinear perception of IR radiation by the eye, using a developed picosecond laser on F₂ ^– centers, are investigated for the first time.Translated from Lazernye Sistemy, pp. 67–86, 1982.     

Complex formation of 1,4,7-tris(β-diphenylphosphinylethyl)-1,4,7-triazacyclononane with divalent copper salts

An investigation of the monoligand complex of 1,4,7-tris(-diphenylphosphinylethyl)-1,4,7-triazacyclononane with divalent copper has been carried out in various solvents using electronic, IR, and ESR spectroscopy. It was found that the five-coordination polyhedron formed in the complex involves only donor atoms of the ligand and has the structure of a tetragonally elongated square pyramid with two nitrogen atoms and two oxygen atoms at the base and a nitrogen atom at the apex. Compared with the copper(II) complex with the corresponding acid, 1,4,7-tris(-dihydroxyphosphinylethyl)-1,4,7-triazacyclononane, the coordination compound studied has a higher order of symmetry. The absence of observable distortions in the case of the acid is probably connected with steric interaction of the bulky phenyl substituents in the test ligand.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, Moscow 117813. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 594–601, March, 1992.     

Temperature dependence of polarizability of diatomic homonuclear molecules

The temperature dependence of the mean polarizability of the H₂, N₂, and O₂ molecules are calculated in the temperature range up to 2000 K. The values of polarizability derivatives of these molecules from the literature are used in the calculation. The temperature dependence of the mean polarizability of molecules is represented in the form of a second degree polynomial.     

Nonlinear dynamics of phase-locked loop with the second-order filter

We study the dynamical regimes of a phase-locked loop with the second-order filter in the control circuit. Regions with different dynamical behavior are identified in the parameter space. Evolution of these regions with varying filter parameters and types of the phase-discriminator characteristic is analyzed. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 3, pp. 267–278, March 2006.