N-derivatives of formaldimines: the reason for the high nitrogen inversion barriers in N-methyl- and N-chloroimines

The energy and electronic parameters of the nitrogen inversion in imines Н2С=NХНn (ХНn = СН3, NH2, OH, F, SiH3, PH2, SH, Cl) have been calculated with the DFT method (B3LYP 6-311+G(d,p)) in terms of natural bond orbital. It has been established that the interactions of the nitrogen lone pair (LP) with the bond orbitals at the imino carbon atom are practically independent of the X atom and contribute to the decrease of the inversion barriers (ΔЕі≠). While nN→σ*X–H, nN↔σX–H and nN↔nX interactions substantially depend on the heteroatom type and promote the increase in the ΔЕі≠ values with the rise in electronegativity of the X atom. The contribution of the interactions of the nitrogen LP with the Rydberg orbitals of the C=N–X group atoms is small and they cannot be the main reason of the decrease in the ΔЕі≠ values when X atoms of the second period are replaced by atoms of the third period of the same group. The interactions of the LP of the X atoms and the X–H bond orbitals with the C=N bond orbitals have the main influence on the inversion barriers. The contribution of nX→π*C=N interactions to the ΔЕі≠ values is dominant. The main reason of the “anomalous” inversion barriers of N-methyl- and Nchloroformaldimines is the destabilization of inversion transition states because of the reduction in the energies of σX–H →π*C=N and nX→π*C=N interactions and the rise in the energies of nN↔nСl interactions. The contributions of electronegativity of ХНn substituents and energies of intramolecular interactions to the ΔЕі≠ values have been determined

Encapsulation of Synthesized Plant Growth Regulator Based on Copper(II) Complex in Chitosan/Alginate Microcapsules

A new copper complex, trans-diaqua-trans-bis [1- hydroxy-1, 2-di (methoxycarbonyl) ethenato] copper (abbreviation Cu(II) complex), was synthesized and its plant growth regulation properties were investigated. The results show a sharp dependence of growth regulation activity of the Cu(II) complex on the type of culture and its concentration. New plant growth regulator accelerated the development of the corn root system (the increase in both length and weight) but showed a smaller effect on the development of the wheat and barley root systems. Stimulation of corn growth decreased with increasing Cu(II) complex concentration from 0.0001% to 0.01% (inhibition at high concentrations—0.01%). The development of corn stems was also accelerated but to a lesser extent. Chitosan-coated calcium alginate microcapsules suitable for delivery of Cu(II) complex to plants were prepared and characterized. Analysis of the FTIR spectrum showed that complex molecular interactions between functional groups of microcapsule constituents include mainly electrostatic interactions and hydrogen bonds. Microcapsules surface exhibits a soft granular surface structure with substructures consisting of abundant smaller particles with reduced surface roughness. Release profile analysis showed Fickian diffusion is the rate- controlling mechanism of Cu(II) complex releasing. The obtained results give new insights into the complexity of the interaction between the Cu(II) complex and microcapsule formulation constituents, which can be of great help in accelerating product development for the application in agriculture

Synthesis, Characterization, and Encapsulation of Novel Plant Growth Regulators (PGRs) in Biopolymer Matrices

Novel plant growth regulators (PGRs) based on the derivatives of dehydroamino acids 2,3-dehydroaspartic acid dimethyl ester (PGR1), Z-isomer of the potassium salt of 2-amino-3-methoxycarbonylacrylic acid (PGR2) and 1-methyl-3-methylamino-maleimide (PGR3) have been synthesized and their growth-regulating properties investigated. Laboratory testing revealed their plant growth-regulating activity. PGR1 showing the most stimulating activity on all laboratory tested cultures were used in field experiments. Results showed that PGR1 is a highly effective environmentally friendly plant growth regulator with effects on different crops. Biopolymeric microcapsule formulations (chitosan/alginate microcapsule loaded with PGR) suitable for application in agriculture were prepared and characterized. Physicochemical properties and release profiles of PGRs from microcapsule formulations depend on the molecular interactions between microcapsule constituents including mainly electrostatic interactions and hydrogen bonds. The differences in the microcapsule formulations structure did not affect the mechanism of PGRs release which was identified as diffusion through microcapsules. The obtained results opened a perspective for the future use of microcapsule formulations as new promising agroformulations with a sustained and target release for plant growth regulation

Взаимодействие N-хлор-N-алкоксикарбаматов с трифторацетатом серебра

В случае взаимодействия метил-N-хлор-N-алкоксикарбаматов с трифторацетатом серебра образуются N,N-бис(метоксикарбонил)-N-алкоксиимиды. Исследование строения N,N-бис(метоксикарбонил)-N-метоксиимида с помощью РСА позволяет доказать наличие аномерного эффекта nO(Me)→σ*NX в NXN-метоксисечовинах (X = OAc, Cl, OMe, N+C5H5).</p

Взаємодія N-хлор-N-алкоксікарбаматів з трифторацетатом срібла

В случае взаимодействия метил-N-хлор-N-алкоксикарбаматов с трифторацетатом серебра образуются N,N-бис(метоксикарбонил)-N-алкоксиимиды. Исследование строения N,N-бис(метоксикарбонил)-N-метоксиимида с помощью РСА позволяет доказать наличие аномерного эффекта nO(Me)→σ*NX в NXN-метоксисечовинах (X = OAc, Cl, OMe, N+C5H5).У разі взаємодії метил-N-хлор-N-алкоксикарбаматів з трифторацетатом срібла утворюються N,N-біс(метоксикарбоніл)-N-алкоксиіміди. Дослідження будови N,N-біс(метоксикарбоніл)-N-метоксиіміду за допомогою РСА дозволяє довести наявність аномерного ефекту nO(Me)→σ*N-X у N-X-N-метоксисечовинах (X = OAc, Cl, OMe, N+C5H5)