Nonsymmetric [Pt(C^N*N′^C′)] Complexes: Aggregation-Induced Emission in the Solid State and in Nanoparticles Tuned by Ligand Structure

Five square-planar [Pt(C^N*N′^C′)] complexes ( Pt1 – Pt5 ) with novel nonsymmetric tetradentate ligands ( L1 – L5 ) were synthesized and characterized. Varying the structure of the metalating aromatic systems result in substantial changes in photophysical properties and intermolecular interaction mode of the complexes in solution and in solid state. The complexes are strongly emissive in tetrahydrofuran solution, with the band maxima ranging from 560 to 690 nm. Three of these complexes ( Pt1 , Pt2 , Pt4 ) afford nanospecies upon injection of their solution into water, which show aggregation-induced emission (AIE) with a strong red shift of emission bands. In the solid state, crystalline samples of these complexes demonstrate mechanochromism upon grinding with a bathochromic shift of the emission. DFT and TD-DFT computational analysis of monomeric Pt1 – Pt5 in solution and model dimeric emitters formed through intermolecular interaction of Pt1 , Pt2 , Pt4 molecules allowed assignment of observed AIE to the ³MMLCT excited states of Pt-Pt bonded aggregates of these complexes.     

Rearrangement of O-vinyl-α-(amino-carbonyl)acetamidoximes to 2-aminopyrroles and 2-pyrrolinones

Rearrangement and cyclization of O-vinyl-α-(aminocarbonyl)acetamidoximes gives two isomeric 2-aminopyrroles and/or 2-pyrrolinones and this depends on the rearrangement route. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1328–1334, September, 2007.     

Macrocyclic amidophosphoryl polyethers: Biological activity,molecular structure,and structure of the complex with calcium thiocyanate

The antihypoxic and anticonvulsant activity of eight new amidophosphoryl derivatives of crown ethers was investigated. It was found that some of them exhibit pronounced antihypoxic activity. The results of an x-ray structural and IR spectroscopic study of dibenzo-N-phenylphosphonyl-14-crown-5 (a=9.818,b=16.062,c=15.925 Å; =124.90°;V=2072 ų;M=417.2;d=1.33 g/cm³ forZ=4, 1955 independent reflections [I>3(I)] in a DAR-UM inCuK radiation,P2 ₁/b space group,R=5.2%) and dibenzo-N-adamantylphosphonyl-14-crown-5 compounds (a=11.077,b=15.936,c=16.771 Å; =56.05°;V=2456 ų;M=486.3;d=1.31 g/cm³ forZ=4, 2164 independent reflections [I>3(I)] in a DAR-UM inCuK radiation,P2₁/b space group,R=5.1%) are reported. Some details of the structure of the dibenzo-N-phenylphosphonyl-14-crown-5-complex with calcium thiocyanate and water are discussed; a polyhedron with a coordination number of six was found for the first time for calcium complexes with macrocyclic ligands. The combined examination of the results of the biological, x-ray structural, and IR spectroscopic study of macrocyclic, 14-member ligands suggested that the nature of the substituents at phosphorus affect the conformational state of the macrocycle, which remains unchanged in complexation in the investigated conditions.Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences, 142432 Chernogolovka. Institute of Physiologically Active Substances, Russian Academy of Sciences, 142432 Chernogolovka. Institute of Organic Chemistry, Ukrainian Academy of Sciences, 252660 Kiev. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2784–2790, December, 1992.     

Evolution of the structure factor in a hyperbolic model of spinodal decomposition

We consider the modification of the Cahn-Hilliard equation when a time delay process through a memory function is taken into account. The memory effects are seen to affect the dynamics of phase transition at short times. The process of fast spinodal decomposition associated with a conserved order parameter - concentration is studied numerically. Details of a semi-implicit numerical scheme used to simulate the kinetics of spinodal decomposition and evolution of the structure factor are discussed. Analysis of the modeled structure factor predicted by a hyperbolic model of spinodal decomposition is presented in comparison with the parabolic model of Cahn and Hilliard. It is shown that during initial periods of decomposition the structure factor exhibits wave behavior. Analytical treatments explain such behavior by existence of damped oscillations in structure factor at earliest stages of phase separation and at large values of the wave-number. These oscillations disappear gradually in time and the hyperbolic evolution approaches the pure dissipative parabolic evolution of spinodal decomposition.     

Experimental test for the hyperbolic model of spinodal decomposition in the binary system

A model has been presented for the physical decay with the relaxation of the diffusion flux described by the hyperbolic diffusion equation. The analysis of such a hyperbolic model provides the predictions for the critical parameters of the decay, which are compared with the conclusions of the Cahn-Hilliard theory. It has been shown that the hyperbolic model predicts the nonlinearity of the dispersion curve for the spinodal decay, which is controlled by the ratio of the diffusion and correlation lengths. The predicted behavior of the dispersion curve is compared with the experimental data on phase separation in binary glasses.     

Trapping of Impurity in a Dilute Solution: Phase-Field Simulation of Solidification

Technical Physics - The process of impurity redistribution in the vicinity of diffuse interface between the liquid and solid phases has been investigated by numerical simulation of nonstationary...     

Application of the model of locally nonequilibrium solidification to the process of structure formation in alloys rapidly quenched by spinning

Solidification of a binary alloy rapidly quenched by spinning [1] has been studied by mathematical simulation.