Andrey A. Karasik

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.

Water-soluble aminomethyl(ferrocenylmethyl)phosphines and their trinuclear transition metal complexes

Abstract Reactions of bis(hydroxymethyl)ferrocenylmethylphosphine ( 1 ) with amino acids ( o -aminobenzoic acid, potassium glycinate and 5-aminoisophthalic acid) lead to the metal-containing phosphino amino acids 1,3-bis(carboxymethyl)-5-(ferrocenylmethyl)-1,3-diaza-5-phosphacyclohexane ( 2 ), bis( o -carboxyphenylaminomethyl)ferrocenylmethylphosphine ( 3 ), and 1,5-bis( meta -dicarboxyphenyl)-3,7-bis(ferrocenylmethyl)-1,5-diaza-3,7-diphosphacyclooctane ( 4 ), respectively. Water-soluble trinuclear complexes 5 and 6 were obtained by complexation of 4 with [MCl 2 (cod)] (M=Pt, Pd; cod=cyclooctadiene) in DMF. Compounds 1 – 6 were characterized by multinuclear NMR and IR spectroscopy and microanalysis.

Synthesis of novel water-soluble heterocyclic phosphino amino acids with bulky aromatic substituents on phosphorus

Abstract One-step syntheses of a number of water-soluble sodium and potassium phosphino amino acid salts from primary arylphosphines (2,4,6-R 3 C 6 H 2 )PH 2 (R=H, Me, Pr i ), formaldehyde and sodium or potassium glycinate, with unsubstituted and 2,4,6-trisubstituted aryl substituents on the phosphorus atom are reported. The structures of the disodium and dipotassium 1,3-di(carboxylatomethyl)-5-aryl-1,3,5-diazaphosphorinanes were established on the basis of IR and 1 H, 13 C and 31 P NMR data.

Novel chiral 1,5-diaza-3,7-diphosphacyclooctane ligands and their transition metal complexes

Reaction of bis(hydroxymethyl)phenylphosphine with (R)- or (S)-α-methylbenzylamine leads to the novel cyclic chiral bisphosphine ligands 1,5-(R,R)- and 1,5-(S,S)-bis(α-methylbenzyl)-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane (1r or 1s). Novel chiral chelate complexes of PtII (2r, 3r and 3s), PdII (4s, 5s) and ReI (6r) have been obtained by reaction of 1r or 1s with [MCl2(cod)] (M = Pt, Pd; cod = 1,5-cyclooctadiene) and [{ReBr(CO)3(thf)}2]. Compounds 1–6 were characterised by multinuclear NMR (1H, 13C, 31P) and IR spectroscopy. The former technique revealed the presence of two inequivalent phosphorus atoms in 6r. The molecular structure of 1r confirmed the absolute configuration of the chiral centers and a chair-chair conformation of the heterocycle with equatorial orientation of the substituents on phosphorus and axial on nitrogen atoms. Compound 1s was used to form a palladium catalyst for the co-polymerisation of carbon monoxide and norbornadiene. The structures of the co-polymers obtained were characterised by GPC, 1H and 13C NMR spectroscopy and elemental analysis.

First representative of optically active P-L-menthyl-substituted (aminomethyl)phosphine and its borane and metal complexes.

The first representative of 1,5-diaza-3,7-diphosphacyclooctanes (1) with chiral L-menthyl substituents on the phosphorus atoms was obtained by condensation of L-menthylphosphine with formaldehyde and p-toluidine. This optically active cyclic bisphosphine readily forms a stable P,P-complex with borane (2) and P,P-chelate complexes with platinum(II) (3) and palladium(II) dichloride (4). The structure of the bisphosphine 1 in solution was elucidated by employing a variety of 1D/2D NMR correlation experiments, and the molecular structure of complex 3 was studied by X-ray crystallography.

Intramolecular Interaction in Heterocyclic Phosphines

Some specific features of space structure, reactivity, complex formation and unusual physical properties of organic and organophosphorus compounds are due to univalent intramolecular interactions. Several intramolecular interactions observed in heterocyclic phosphines will be discussed in this current paper.

Electrochemical evaluation of a number of nickel complexes with P,N-heterocyclic ligands as catalysts for hydrogen oxidation/release

The efficiency of a series of nickel complexes of P,N-cyclic ligands (potential catalysts in hydrogen fuel cells) in the electrocatalytic reduction of H+ to hydrogen and the oxidation of H2 in the coordination shell/cavity of the catalyst in DMF (acetonitrile with variable nickel: ligand ratio (1: 1, 1: 2) and different counterions (X=Cl− and BF4−)) was tested, and the most favorable conditions and structures were determined. The relation between the activity of the catalysts and the values of the electrochemical gap was found.

Structure, conformation, and dynamics of P,N-containing cyclophanes in solution.

3D structures in solution of highly symmetrical N,P-containing macrocycles were established by a variety of 2D NMR correlation techniques. It was shown that a number of magnetically equivalent fragments in such symmetrical systems can be estimated by NMR diffusion measurement. The title compounds adopt a helical conformation of the macrocycles in solution. The extent of twisting and the size of the intramolecular cavity are determined by steric hindrance of the aromatic substituents on the exocyclic phosphorus atoms with phenylene and dimethylmethylene groups forming the macrocycle. In solution these macrocycles host aromatic guests inside the cavity.

Heterocyclic Phosphorus Ligands in Coordination Chemistry of Transition Metals

Modern stage of development of organometallic and co-ordination chemistry is characterised by the wide use of polyfunctional ligands with structurally rigid fragments. On the base of such ligands an unusual labile and polynuclear complexes -precursors of the homogeneous catalysts, have been designed. Cyclic organophosphorus compounds pertain to the ligands of such type.