Mononuclear Copper(I) 3-(2-pyridyl)pyrazole Complexes: The Crucial Role of Phosphine on Photoluminescence

A series of emissive Cu(I) cationic complexes with 3-(2-pyridyl)-5-phenyl-pyrazole and various phosphines: dppbz (1), Xantphos (2), DPEPhos (3), PPh₃ (4), and BINAP (5) were designed and characterized. Complexes obtained exhibit bright yellow-green emission (ca. 520–650 nm) in the solid state with a wide range of QYs (1–78%) and lifetimes (19–119 µs) at 298 K. The photoluminescence efficiency dramatically depends on the phosphine ligand type. The theoretical calculations of buried volumes and excited states explained the emission behavior for 1–5 as well as their lifetimes. The bulky and rigid phosphines promote emission efficiency through the stabilization of singlet and triplet excited states.     

Chromophoric macrocycles from the oxidation of bis(aminofurazanylic) ethers of 1,2-diols

A series of chromophoric azofurazan-containing macrocycles 6a–c and 7a–d were synthesized from bis(aminofurazanylic) ethers of 1,2-diols 4a–d by dibromoisocyanurate oxidation. The macrocycle closure is a result of NN bond formation. An ion-binding ability of these compounds was tested. The macrocycles were characterized by NMR, MS, IR, and UV spectroscopy. The X-ray crystal structures of the macrocycles 6a, 7c , and linear counterpart 12 are reported. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:131–145, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10226     

Synthesis of phosphorylated 1,3,5‐oxadiazines via N‐acyltrifluoroacetimidoylphosphonates

N‐Benzoyl‐ and N‐methoxycarbonyltrifluoroacetimidoylphosphonates react with dimethylcyanamide in a [4+2]‐cycloaddition to give 4‐phosphorylated 1,3,5‐oxadiazines. The structures of the products were confirmed by NMR (¹H, ¹³C, ¹⁹F, ³¹P) and IR spectra and by XRD analysis. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:22–26, 2002; DOI 10.1002/hc.1102     

A Novel Bicyclophosphite Ligand Directly Yields Rhodium Hydride Complexes

Summary.  Complexation of Rh(I) with o, o′-dimethylene-(tris-p-cresyl)-bicyclophosphite (BCP, 1) has been investigated in solution by NMR, semi-empirical quantum mechanical, and molecular mechanics calculations. ¹H and ³¹P NMR spectroscopic data show that when the BCP/Rh ratio exceeds 2, Rh hydride complexes of the composition RhH(BCP)₃ and RhH(BCP)₄ are formed. The source of the hydride ion is the ligand itself; most probably, H⁻ originates from the bridging CH₂ groups of BCP. The chemical shifts of these protons are sensitive to complexation due to the considerable electron density of HOMO and LUMO at one of the bridging CH₂ moieties. Molecular mechanics simulations of the molecular structure of these complexes show that two cavities are formed in [Rh(BCP)₃]⁺ by the aromatic rings of the ligands. These cavities may alternatively open and close, thus providing for a flexibly shielded catalytic site which explains the unusual catalytic behaviour of Rh complexes with BCP in hydrogenation and hydroformylation reactions. Received February 15, 2001. Accepted (revised) April 23, 2001     

A Novel Bicyclophosphite Ligand Directly Yields Rhodium Hydride Complexes

 Complexation of Rh(I) with o, o′-dimethylene-(tris-p-cresyl)-bicyclophosphite (BCP, 1) has been investigated in solution by NMR, semi-empirical quantum mechanical, and molecular mechanics calculations. ¹H and ³¹P NMR spectroscopic data show that when the BCP/Rh ratio exceeds 2, Rh hydride complexes of the composition RhH(BCP)₃ and RhH(BCP)₄ are formed. The source of the hydride ion is the ligand itself; most probably, H⁻ originates from the bridging CH₂ groups of BCP. The chemical shifts of these protons are sensitive to complexation due to the considerable electron density of HOMO and LUMO at one of the bridging CH₂ moieties. Molecular mechanics simulations of the molecular structure of these complexes show that two cavities are formed in [Rh(BCP)₃]⁺ by the aromatic rings of the ligands. These cavities may alternatively open and close, thus providing for a flexibly shielded catalytic site which explains the unusual catalytic behaviour of Rh complexes with BCP in hydrogenation and hydroformylation reactions.     

Synthesis of difurazanyl ethers from 4,4′‐dinitroazoxyfurazan

Nonselective attacks at the carbon bonded to a nitro group and carbon bonded to the N(O) atom of the azoxy group were observed in the reactions of 4,4′‐dinitroazoxyfurazan with bases and nucleophiles. A mechanism is presented to account for both of the pathways to products. A series of new difurazanyl ether derivatives was synthesized. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:48–56, 2000     

Promising lines of investigations in the realms of laboratory astrophysics with the aid of powerful lasers

The results of work on choosing and substantiating promising lines of research in the realms of laboratory astrophysics with the aid of powerful lasers are presented. These lines of research are determined by the possibility of simulating, under laboratory conditions, problematic processes of presentday astrophysics, such as (i) the generation and evolution of electromagnetic fields in cosmic space and the role of magnetic fields there at various spatial scales; (ii) the mechanisms of formation and evolution of cosmic gamma-ray bursts and relativistic jets; (iii) plasma instabilities in cosmic space and astrophysical objects, plasma jets, and shock waves; (iv) supernova explosions and mechanisms of the explosion of supernovae featuring a collapsing core; (v) nuclear processes in astrophysical objects; (vi) cosmic rays and mechanisms of their production and acceleration to high energies; and (vii) astrophysical sources of x-ray radiation. It is shown that the use of existing powerful lasers characterized by an intensity in the range of 10¹⁸–10²² W/cm² and a pulse duration of 0.1 to 1 ps and high-energy lasers characterized by an energy in excess of 1 kJ and a pulse duration of 1 to 10 ns makes it possible to perform investigations in laboratory astrophysics along all of the chosen promising lines. The results obtained by experimentally investigating laser plasma with the aid of the laser facility created at Central Research Institute of Machine Building (TsNIIMash) and characterized by a power level of 10 TW demonstrate the potential of such facilities for performing a number of experiments in the realms of laboratory astrophysics.