Platinum(ii) and palladium(ii) complexes with electron-deficient meso-diethoxyphosphorylporphyrins: synthesis, structure and tuning of photophysical properties by varying peripheral substituents.

A series of electron-deficient platinum(ii) and palladium(ii) meso-(diethoxyphosphoryl)porphyrins, namely [10-(diethoxyphosphoryl)-5,15-bis(p-tolyl)porphyrinato]palladium(ii) (PdDTolPP), {10-(diethoxyphosphoryl)-5,15-bis[p-(methoxycarbonyl)phenyl]porphyrinato}palladium(ii) [PdD(CMP)PP], [10-(diethoxyphosphoryl)-5,15-dimesitylporphyrinato]palladium(ii) (PdDMesPP), [5-(diethoxyphosphoryl)-10,15,20-trimesitylporphyrinato]palladium(ii) (PdTMesPP) and the corresponding platinum(ii) compounds, were synthesized and structurally characterized in solution by means of H, C, P NMR spectroscopies and in the solid state by single crystal X-ray diffraction [PdDTolPP, PdD(CMP)PP and PtD(CMP)PP]. Their optical and photophysical properties (UV-vis absorption, luminescence and excitation spectra, phosphorescence quantum yields and lifetimes) were also determined. The complexes under investigation emit at room temperature in the near-infrared region (670-770 nm).

Reverse Arene Sandwich Structures Based upon π-Hole⋅⋅⋅[M ] (d M=Pt, Pd) Interactions, where Positively Charged Metal Centers Play the Role of a Nucleophile.

The complexes [Pt(tpp)] (H tpp=tetraphenylporphyrin), [M(acac) ] (M=Pd, Pt, Hacac=acetylacetone), and [Pd(ba) ] (Hba=benzoylacetone) were co-crystallized with highly electron-deficient arene systems to form reverse arene sandwich structures built by π-hole⋅⋅⋅[M ] (d M=Pt, Pd) interactions. The adduct [Pt(tpp)]⋅2 C F is monomeric, whereas the diketonate 1:1 adducts form columnar infinity 1D-stack assembled by simultaneous action of both π-hole⋅⋅⋅[M ] and C⋅⋅⋅F interactions. The reverse sandwiches are based on noncovalent interactions and calculated ESP distributions indicate that in π-hole⋅⋅⋅[M ] contacts, [M ] plays the role of a nucleophile.

Thermodynamic model of nonequilibrium phase transitions.

Within the scope of a thermodynamic description using the maximum entropy production principle, transitions from one nonequilibrium (kinetic) regime to another are considered. It is shown that in the case when power-law dependencies of thermodynamic flux on force are similar for two regimes, only a transition accompanied by a positive jump of thermodynamic flux is possible between them. It is found that the difference in powers of the dependencies of thermodynamic fluxes on forces results in a number of interesting nonequilibrium transitions between kinetic regimes, including the reentrant one with a negative jump of thermodynamic flux.

Experimental investigation of the onset of instability in a radial Hele-Shaw cell.

The initial stage of interface instability upon radial displacement of a fluid in a Hele-Shaw cell is investigated. An air-silicone oil system is analyzed. The critical radii of stability relative to long-wave perturbations are determined.

Conformational behavior of diblock comb copolymers.

The conformational behavior of a single diblock copolymer chain with comb blocks is studied by computer simulation. The comb blocks have equal lengths of the backbones and side chains and differ only by the degree of grafting of the side chains. The collapse behavior is studied for two cases: (i) comb diblock copolymer with attracting backbones of the blocks and swollen side chains and (ii) comb diblock copolymer with attracting monomer units of the side chains of the blocks and swollen backbones.