Elvira I. Musina

Synthesis of novel water-soluble linear and heterocyclic phosphino amino acids from 2-phosphinophenols or 2-phosphinophenolethers, formaldehyde and amino acids

Acyclic and cyclic amino acid derivatives of 2-phosphinophenols have been synthesised by reaction of primary phosphinophenols (4-R-2-H2PC6H3OH; R=H, Me, OMe) 1a–c with formaldehyde and amino acids (o- and p-aminobenzoic acid, l-lysine) via in situ formed hydroxymethyl species 2a–c. Condensation reactions with glycine did not afford defined products except when the methoxymethyl and tetrahydropyranyl ethers of 1d,e were used instead of the hydroxy compounds. o-Aminobenzoic acid gives rise to linear bis(o-carboxyphenylaminomethyl)phosphines 3a–e. p-Aminobenzoic acid, dependent on the molar ratio, affords bis(p-carboxyphenylaminomethyl)phosphines 4a,d as well as eight-membered heterocyclic 1,5,3,7-diazadiphosphacyclooctanes 5a–e. The aliphatic amino acids glycine and l-lysine form six-membered heterocyclic 1,3,5-diazaphosphorinanes 6d and 7a–e, respectively, in presence of excess formaldehyde. l-lysine differs from glycine by reaction at the terminal amino group. The structures of the compounds have been elucidated by multinuclear NMR spectroscopy. The salts of the phosphino amino acids are soluble in water. Water solubility increases with the number of hydrophilic groups, i.e. free phenols are more soluble than their ethers. Ligand concentrations in water from 0.1 to 1 M were observed.

New Functional Cyclic Aminomethylphosphine Ligands for the Construction of Catalysts for Electrochemical Hydrogen Transformations

Eight-membered cyclic functional bisphosphines, namely 1,5-di-aryl-3,7-di(2-pyridyl)-1,5-diaza-3,7-diphosphacyclooctanes (aryl=2-pyridyl, m-tolyl, p-tolyl, diphenylmethyl, benzyl, (R)-(+)-(α-methyl)benzyl), with 2-pyridyl substituents on the phosphorus atoms have been synthesized by condensation of 2-pyridylphosphine, formaldehyde, and the corresponding primary amine. The structures of some of these bisphosphines have been investigated by X-ray crystallography. The bisphosphines readily form neutral P,P-chelate complexes [(κ(2)-P,P-L)MCl2], cationic bis-P,P-chelate complexes [(κ(2)-P,P-L)2 M](2+), or a five-coordinate complex [(κ(2)-P,P-L)2 NiBr]Br. The electrochemical behavior of two of the nickel complexes, and their catalytic activities in electrochemical hydrogen evolution and hydrogen oxidation, including the fuel-cell test, have been studied.

A stimuli-responsive Au(I) complex based on an aminomethylphosphine template: synthesis, crystalline phases and luminescence properties

Herein we report the synthesis of a stimuli-responsive binuclear Au(I) complex based on the 1,5-bis(p-tolyl)-3,7-bis(pyridine-2-yl)-1,5-diaza-3,7-diphosphacyclooctane ligand, which is a novel template for the design of luminescent metal complexes. In the solid state, the complex obtained gives three different crystalline phases, which were characterized by XRD analysis. It was also found that the crystalline phases can be reversibly interconverted by recrystallization or solvent vapour treatment. The emission of these phases varies in the 500–535 nm range. Quite unexpectedly, the emission energy of these phases is mostly determined by the non-covalent interactions of the solvent molecules with the ligand environment, which have nearly no effect on the Au–Au interactions in the chromophoric centre. The complex obtained demonstrates thermo/solvatochromism to display greenish emission in a DCM matrix and blue emission in an acetone matrix at 77 K, in contrast to the blue emission of the phase containing a DCM molecule and greenish-yellow emission of the acetone solvate in a crystal cell at room temperature. The potentially important role of co-crystallized solvent molecules in the ligand-based emission of the complex obtained is supported by DFT calculations.

Nickel complexes with cyclic ligands containing P and N atoms as coordination sites: novel biomimetic catalysts for hydrogen oxidation

Nickel complexes with new cyclic ligands containing phosphorus and nitrogen atoms as coordination sites are novel efficient catalysts for hydrogen oxidation. A systematic study of their electrochemical properties made it possible to classify the nickel systems in question into four groups according to the sequence of electron transfer processes in the reduction (MII-MI-M0) and to the nature of solvents and counterions. Regularities of catalytic transformations involving nickel complexes with P,N-cyclic ligands in the H2 oxidation reaction in the coordination sphere of the catalyst and a correlation between the structure of the complex and its redox properties were established. The most efficient catalysts contain phenyl and 2-pyridyl substituents at the phosphorus atom and benzyl or 2-pyridyl substituents at the nitrogen atom.

FIRST EXAMPLE OF 14-MEMBERED CYCLIC AMINOMETHYLPHOSPHINE

Abstract We report here a synthesis and molecular structure of novel 1,8-diisopropyl-3,6,10,13-tetraphenyl-1,8-diaza-3,6,10,13-tetraphosphacyclotetradecane.

“Host–guest” binding of a luminescent dinuclear Au(I) complex based on cyclic diphosphine with organic substrates as a reason for luminescence tuneability

This work introduces a luminescent dinuclear Au(I) complex with a cyclic PNNP ligand ((AuCl)2L) as a “host” molecule with two binding sites, “upper” and “lower”. The “upper” binding site is nucleophilic due to two preorganized Au–Cl moieties, while the “lower” one is electrophilic due to positive partial charges of hydrogen atoms of P–CH2–N moieties. The “host–guest” binding is a reason for both solvent- and substrate-induced tuning of the complex luminescence. Organic cations, namely N-methylpyridinium and trimethylammonium, are revealed as substrates able to bind via the “upper” site of the complex. Acetone, diphenylketone, DMSO, DMF and acetonitrile exemplify substrates able to bind with both the binding sites of the complex. The binding via “lower” sites leads to changes in mutual arrangement of pyridyl moieties and P–Au bonds of the complex, which results in a more pronounced effect on the excited state energy relative to the binding via the “upper” site. Substrate-induced tuning of the luminescence is affected by the nature of the solvent due to competitive “host–guest” binding of (AuCl)2L with solvent molecules.

Synthesis of 1-(pyridylalkyl)-1-aza-3,6-diphosphacycloheptanes

Reactions of 1,2-bis[(hydroxymethyl)(phenyl)phosphino]ethane with primary pyridylalkylamines gave earlier unknown 1-aza-3,6-diphosphacycloheptanes containing the pyridyl group in the exocyclic substituent. The reactions were found to be stereoselective, preferentially yielding the racemate with the RR/SS-configuration of the P atoms. A mixture of diastereomers of 3,6-diphenyl-1-[2-(2-pyridyl)ethyl]-1-aza-3,6-diphosphacycloheptane reacted with dichloro(cycloocta-1,5-diene)platinum(II) to give cis-P,P-chelate complexes from the meso-isomer and bridged oligomeric complexes from the racemate.

New aminomethylphosphines with cyanophenyl substituents at the nitrogen atoms

A condensation of bis(hydroxymethyl)arylphosphines with 3- and 4-aminobenzonitriles leads to the corresponding 3,7-diaryl-1,5-bis(cyanophenyl)-1,5-diaza-3,7-diphosphacyclooctanes. Acyclic (aryl)bis[N-(2-cyanophenyl)aminomethyl]phosphines are formed in the case of 2-aminobenzonitrile. Molecular and crystalline structure of the compounds obtained was studied by X-ray diffraction analysis.

Nickel(II) Complexes of Novel P,N-Heterocycles Based on Pyridylphosphines

Abstract Novel 1,5-diaza-3,7-diphosphacyclooctanes were synthesized by Mannich-type condensation of pyridylphosphine, formaldehyde, and primary amines. Their interaction with Ni(II) salts containing different counterions was studied. GRAPHICAL ABSTRACT

New Biomimetic Catalysts for the Electrochemical Processes on the Basis of Redox-Active Macrocyclic Frame Structures

Abstract Efficient catalytic systems mimicking the action of metalloenzymes based on cyclic frame structures containing phosphorus, nitrogen, and sulfur coordinating atoms for hydrogen oxidation or reduction under mild conditions are proposed. GRAPHICAL ABSTRACT