Search

The row of metallocyclic dinuclear gold(I) complexes with cyclic diphosphines, namely, P-pyridylethyl-substituted 1,5-diaza-3,7-diphosphacyclooctanes, has been obtained. Further interaction of the dinuclear gold(I) complexes with copper(I) iodide gave the first examples of hexanuclear AuI/CuI complexes containing two unusual trinuclear AuICu2I2 fragments. The structures of di- and hexanuclear complexes were confirmed by NMR spectroscopy, ESI mass spectrometry, elemental analysis, and single-crystal X-ray diffraction. All of the obtained complexes are moderate emitters in the solid state. Dinuclear gold(I) complexes displayed a greenish emission with the maxima in the emission spectra at ca. 550 nm. The obtained hexanuclear heterobimetallic AuI/CuI complexes are triplet solid-state blue emitters with the maximum in the emission spectra at 463 and 484 nm. According to the TD-DFT calculations, the observed emission of all studied complexes had a triplet origin and was caused by the 3CC or 3(MLCT) T1 → S0 transitions for dinuclear and hexanuclear complexes, respectively.

New bi- and trinuclear gold(I) complexes are synthesized by the reactions of gold(I) chloride or tetrahydrothiophenegold(I) chloride with 1,5-di(p-tolyl)-3,7-diphenyl-1,5,3,7-diazadiphosphacyclooctane taken in various ratios. The structures of the synthesized compounds are confirmed by NMR spectroscopy, elemental analysis, and X-ray diffraction analysis (CIF files ССDC nos. 1974032 (I) and 1974031 (II)). Unlike P-pyridyl-containing 1,5-diaza-3,7-diphosphacyclooctanes, P-phenyl-substituted ligands undergo no rearrangements with ring expansion during the formation of the trinuclear gold(I) complexes.

The steric and electronic structures of 1,3-diaza-5-phoaphacyclohexane with the pyridyl substituent at the phosphorus atom and a series of model 1,3-diaza-5-phosphacyclohexanes (potential ligands for the synthesis of luminescent transition metal complexes) were studied using IR and UV spectroscopy combined with quantum chemical calculations. Relationships between the electronic structures, spectral characteristics, and donor—acceptor properties of the substituents were revealed. The relationships can further be used for the target synthesis of complexes with specified optical properties.

A family of helical dinuclear copper(I) pyridylphospholane complexes [Cu2L3X]X (X = BF4−, Cl− and Br−) was prepared. The family includes the first examples of this type of complex based on copper(I) chloride and copper(I) bromide. The two isomers typical of this class of compounds, namely head-to-head and head-to-tail complexes, were studied in solution by spectroscopic and optical methods, and in the solid state by X-ray diffraction. Furthermore, the solid-state luminescence of the complexes at different temperatures was studied, and the results were interpreted using quantum-chemical calculations. It was shown that the luminescence of the complexes is attributed to the 3(M + X)LCT transitions.

For the first time, the 3(X + M)LCT origin of both the lowest excited triplet states of dual-emissive tetranuclear copper(I)-iodide complexes with the octahedral Cu4I4 core has been revealed using quantum chemical computations in contrast to the conventional assignment of the lowest-energy emission to the 3CC state. The unusual thermochromic behavior shown for dual emission from these states of Cu4I4 clusters stabilized by P,N-ligands allows optical ratiometric thermal sensing in a broad temperature range.

Cyclic aminomethylphosphines in general and 1,5-diaza-3,7-dihposphacyclooctanes in particular are widely used for the design of d10-metal complexes with catalytic or luminescent properties. 1,5-Dia...

A variety of gold(I) and copper(I) complexes based on heterocyclic phosphine platform has been obtained. Due to the presence of exocyclic chromophoric pyridyl groups in the ligands complexes demonstrate noticeable phosphorescence. Cyclic nature of the phosphine ligands is responsible for supramolecular host-behavior of the complexes. Unique structure of complexes on a scaffold of the cyclic PNNP ligands favors the stimuli-induced structural reorganizations followed by stimuli-responsive luminescence. This, in turn, makes the complexes versatile building blocks for bottom-up design of smart nanomaterials for analytical and biomedical applications.

The row of metallocyclic dinuclear gold(I) complexes with cyclic diphosphines, namely, P-pyridylethyl-substituted 1,5-diaza-3,7-diphosphacyclooctanes, has been obtained. Further interaction of the dinuclear gold(I) complexes with copper(I) iodide gave the first examples of hexanuclear Au

The present work represents interactions between the core-shell nanoparticles and different proteins, exemplified by lysozyme (LSZ), pepsin, bovine serum albumin (BSA), thioredoxin (TRX) and yellow fluorescent protein (YFP). The core-shell morphology derives from the non-covalent deposition of polyethyleneimine (PEI) onto nanoprecipitated luminescent complex (AuCl)2L (L is cyclic PNNP ligand). Analysis of the data obtained by DLS, CD spectroscopy, luminescence derived from both (AuCl)2L and YFP reveal the electrostatically driven interaction of negatively charged proteins with the shell of PEI-(AuCl)2L. The fluorescence of YFP enables to reveal the inclusion of the protein molecules into the shell. The lack of any luminescent response of PEI-(AuCl)2L on TRX conforms its electrostatically driven interactions with the shell which, in turn, excludes a binding of the exposed thiol moieties with (AuCl)2L. The negatively charged surface of pepsin provides the greatest recharging of the PEI-based shell versus the other proteins, which is followed by the enhanced luminescence of (AuCl)2L. The significant effect of PEI-(AuCl)2L on the CD spectra of LSZ followed by the decreased intensity of (AuCl)2L-based luminescence points to specific interaction mode of PEI-(AuCl)2L with LSZ. The flow cytometry and fluorescent microscopy measurements revealed efficient internalization of PEI-(AuCl)2L into the Wi-38 cell samples resulting in the efficient staining of all cell organelles. The concentration dependent cytotoxicity of PEI-(AuCl)2L is detectably enhanced by LSZ, which is correlated with its interaction mode with the nanoparticles.

The present work represents new facile route for synthesis of luminescent hydrophilic core-shell colloids, where the luminescence results from Au(I) complex (AuCl)2L with cyclic PNNP ligand (L). The synthesis is based on solvent mediated aggregation of (AuCl)2L in aqueous organic solutions. Instability of (AuCl)2L in aqueous organic solutions was minimized by specific hydrophilic shell deposition arisen from electrostatically driven adsorption of polyethylenimine onto (AuCl)2L-based cores. Luminescence of the colloids is stable for week at least due to restricted degradation of the luminescent complex at the interface and high positive exterior charge of the colloids. The sensing properties of the colloids towards thiols results from their complex formation with Au+ ions. The thiol-induced stripping of Au+ ions from the colloids quenches the luminescence. The optimal conditions for fluorescent recognition of cysteine, homocysteine and glutathione with lower detection limits about 1 μM are highlighted in the work.

The reaction of gold(i) chloride with two molecules of 1,5-diaza-3,7-diphosphacyclooctane derivative causes their reorganization into 16-membered macrocyclic tetraphosphine ligand. The structure of the trinuclear gold(i) complex obtained was confirmed by X-ray analysis. The dynamic equilibrium between dinuclear gold(i) complexes with eight-membered cyclic ligands and the trinuclear gold(i) complex with 16-membered ones has been revealed.

The present work introduces synthesis, structure and spectroscopic properties of novel water soluble dicationic binuclear Au(I) complex [Au2L2]2+ with bridge P,P-coordination, where L is cyclic PNNP ligand 1,5-bis(p-tolyl)−3,7-bis(pyridine-2-yl)−1,5-diaza-3,7-diphosphacyclooctane. Its ion-pairing with anionic hexarhenium cluster complexes ([{Re6S8}(OH)6]4– and [{Re6S8}(CN)6]4–) is represented herein as a reason for bottom-up design of supramolecular heterometallic assemblies with the enhanced cluster-centered luminescence and heterometallic colloids with high luminescence response to acidification in the range of pH 6.0-5.5.

Several new mono- and binuclear copper(I) complexes of pyridyl containing 1,5-diaza-3,7-diphosphacylcooctanes with bis-P,P-chelate and unusual P,P-bridged coordination modes of heterocyclic ligands were obtained and characterized. The 1,5-diaza-3,7-diphosphacyclooctane, containing p-tolyl substituents at nitrogen atoms forms bis-P,P-chelate mononuclear as well as metalacyclic binuclear complexes with P,P-bridged coordination mode of a ligand, whereas the N-1-phenylbezyl substituted ligand gives the expected P,P-chelate complexes only. Reasons for the differences in coordination modes have been found in the ligands geometry, where configuration of nitrogen atoms plays an important role.

The first representatives of the tetranuclear gold(i) complexes of P,N-containing cyclophanes with two 1,5-diaza-3,7-diphosphacyclooctane rings incorporated into the macrocyclic core have been obtained. The complexation leads to a change in ligand conformations so that the diazadiphosphacyclooctane fragments of the complexes adopt twist-chair conformations, and two of the four gold(i) ions are located over and under the partially collapsed macrocyclic cavity. The complexes demonstrate moderate solid-state green emission.

The present work introduces various synthetic and post-synthetic modes of co-doping of oleate-oleylamine-stabilized Cu(2−x)S cores with red emitting [Ru(dipy)3]2+ into amino-modified silica nanoparticles (SNs) with the aim to combine chemodynamic therapy (CDT) with cellular uptake and imaging functions. Thereto, the ROS generation by the Cu(2−x)S embedded into the SNs was manifested by the spin trap facilitated ESR technique and correlated with such parameters as size of the embedded cores, content and oxidation extent of copper ions. The parameters were varied through the different extent of an oxidative degradation of the embedded Cu(2−x)S cores by their post-treating with histidine, polyethylenimine and citrate-stabilized carbon dots (CDs). The treating by CDs was chosen as the optimal post-synthetic modification of the composite SNs due to combination of CDT with high stability to aggregation. The green or dual green-red emission of the CD-treated composite SNs visualizes their cell internalization and intracellular localization by means of fluorescence and confocal microscopy methods. Correlation of cytotoxicity data of the differently treated composite SNs with their ability to ROS generation and the intracellular localization highlight the enhanced cell internalization and nuclear confinement of the CD-treated composite SNs as the factor enhancing their cytotoxicity in greater extent than the CDT function.

Electrostatically driven self-assembly of [Au2L2]2+ (L is cyclic PNNP ligand) with [{Mo6I8}(L')6]2− (L' = I−, CH3COO−) in aqueous solutions is introduced as facile route for combination of therapeutic and cellular contrasting functions within heterometallic colloids (Mo6-Au2). The nature of L' affects the size and aggregation behavior of crystalline Mo6-Au2 aggregates, which in turn affect the luminescence of the cluster units incorporated into Mo6-Au2 colloids. The spin trap facilitated electron spin resonance spectroscopy technique indicates that the level of ROS generated by Mo6-Au2 colloids is also affected by their size. Both (L' = I−, CH3COO−) Mo6-Au2 colloids undergo cell internalization, which is enhanced by their assembly with poly-DL-lysine (PL) for L' = CH3COO−, but remains unchanged for L' = I−. The colloids PL-Mo6-Au2 (L' = CH3COO−) are visualized as huge crystalline aggregates both outside and inside the cell cytoplasm by confocal microscopy imaging of the incubated cells, while the smaller sized (30–50 nm) PL-Mo6-Au2 (L' = I−) efficiently stain the cell nuclei. Quantitative colocalization analysis of PL-Mo6-Au2 (L' = CH3COO−) in lysosomal compartments points to the fast endo-lysosomal escape of the colloids followed by their intracellular aggregation. The cytotoxicity of PL-Mo6-Au2 differs from that of Mo6 and Au2 blocks, predominantly acting through apoptotic pathway. The photodynamic therapeutic effect of the PL-Mo6-Au2 colloids on the cancer cells correlates with their intracellular trafficking and aggregation.

1,5-bis(R)-3,7-bis[2-(pyridine-2′-yl)ethyl)-1,5-diaza-3,7-diphosphacyclooctanes 1 and 2 and their copper(I) complexes 3 and 4 were developed. The butterfly-shaped copper-iodide core and unusual P,N-chelate and P,P-bridged coordination mode of the heterocyclic ligand in the dinuclear complexes 3 and 4 were revealed. Complexes 3 and 4 display emission in green range of spectra, with lifetimes in a microsecond domain and quantum yields of luminescence in solid-state up to 38 %. Thermochromic effects found for the phosphorescence of 4 in solutions are ascribed to rigidochromism.

Rational design of title ligands and their transition metal complexes gave the high effective catalysts for hydrogen economy and perspective “stimuli-responsive” luminescent materials. Together with the above novel cyclic aminomehtylphospine ligands have showed a row of unpredicted properties like spontaneous formation of macrocyclic molecules, unique reversible slitting of macrocycles on to the smaller cycles, rapid interconversion of the isomers catalyzed by both acids and transitional metals, bridging behavior of usually chelating ligands and unexpected high influence of handling substituents on N-atoms on to the catalytic and luminescent properties of P-complexes.

Luminescence thermometry became one of the most rapidly developing scientific areas in the last decade. A lot of scientific groups are working on the design of a highly sensitive and accurate thermometer based on monitoring the chosen luminescence parameter. However, it is still a challenge to create a multimode sensor utilizing several temperature-dependent parameters for thermometry, which could broaden the working range and improve thermometric characteristics. Here, we successfully demonstrate the binuclear helical charged complex [L3Cu2](BF4)2 (L = 1-pyridine-2-ylphospholane) in head-to-head configuration with solid-state single-band emission as a multimode optical thermometer. Thermal sensing was provided using luminescence intensity ratio, spectral line position, bandwidth, and lifetime. Ratiometric temperature determination was performed by the successful use of deconvolution analysis. The thermometric performance was studied in terms of relative thermal sensitivity, which was varied from 0.93 % K−1 for line position to 0.11 % K−1 for bandwidth at 298 K. The obtained results show Cu(I) complex as a cheap multimode luminescence thermal sensor in the 98–393 K range.

The 1,5-di(p-iodophenyl)-3,7-bis(pyrid-2-)yl-1,5-diaza-3,7-diphosphacyclooctane was obtained via reaction of pyridylphosphine, paraformaldehyde and 4-iodoaniline. The ligand reacts with Pd(COD)Cl2 ...

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.

A novel type of cyclic P,N-ligands, pyridyl containing phospholanes, has been synthesized in a moderate yield by the reaction of primary phosphines with 1,4-dichlorobutane in a superbasic medium. A series of homo tetranuclear octahedral Cu4I4L2, dinuclear tetrahedral Cu2I2L3, and dinuclear "head-to-tail" Cu2I2L2 luminescent complexes with these ligands were obtained. All the compounds were characterized using a range of spectroscopic and computational techniques, and in the case of some Cu4I4L2 and Cu2I2L3 complexes, by single crystal X-ray diffraction. The structural diversity of the obtained complexes was reflected in their photophysical properties: phosphorescence spectra of the compounds display emission in broad spectral range of 471-615 nm. TD-DFT computations allow the assignment of a single emission band around 550 nm for Cu2I2L3 complexes and 471 nm for Cu2I2L2 complex to a vertical triplet-singlet transition from a metal-to-ligand and halide-to-ligand charge-transfer (3)(M + X)LCT excited state, whereas a second band at around 600 nm in the spectra of octahedral Cu4I4L2 complexes was assigned predominantly to Cu4I4 cluster-centered ((3)CC) excited state.

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.

The seven-membered cyclic bisphosphines 3–5 were synthesized by a Mannich-like condensation reaction of 1,2-bis(phenylphosphino)ethane, formaldehyde and primary amines (tert-butylamine, 1,1-(diphenyl)methylamine, (2R)-tetrahydro-2-furanylmethylamine) as a mixture of RPRP/SPSP (rac, 3a–5a) and RPSP (meso, 3b–5b) stereoisomers. The structures of the rac stereoisomers 3a–5a were investigated by X-ray crystal structure analyses. The RR/SS to RS isomerization of 3–5 and oxidation processes of 4 in solution were studied. Platinum(II) P,P-chelate complexes are formed exclusively from rac/meso mixtures of 3–5.

Novel cyclic phosphino amino pyridines and their mono- and binuclear Ni(II), Cu(I), and Au(I) complexes have been obtained. It has been shown that catalytic activity of the nickel-(II) complexes in...

Two new types of systems with an electrochemically controlled binding of electron-accepting particles with tetra(methyl viologen) calix[4]resorcinol MVCA-C5 8+ were developed. Control is carried out by the reversible reduction of viologen units. In one of the systems, an equimolar amount of the dication of bis-P,P-chelate platinum(II)—3,7-di(2-pyridyl)-1,5diphenyl-1,5-diaza-3,7-diphosphacyclooctane complex ([PtL1 2]2+) is bound by the reduced form MVCA-C5 0 and is not bound to the octacation MVCA-C5 8+ and tetra(radical cation) MVCA-C5 4+•. In another ternary system MVCA-C5 8+—[PtL1 2]2+—[Fe(CN)6]3–, the reversible switching occurs from the original unbound state to the state with selective binding of equimolar amounts of [Fe(CN)6]4– or [PtL1 2]2+ by calixresorcinol. Supramolecular complexes form insoluble associates in both systems.

1,5-diazadiphosphacyclooctanes are a type of ligands which are widely used in the catalytic or luminescent complexes construction. The condensation reaction is a main synthetic route to the obtaining of these ligands. These route is a convenient way, but the utilization of the primary phosphines or amines is limited by the availability of the amines or stability of phoshines. Thus we suggest another way for the design of ligands with desired properties, which is based on the cross-coupling reactions between 1,5-diaza-3,7-diphosphacyclooctanes containing p-iodophenyl groups and corresponding substrates for the Suzuki, Ullmann or Sonogashira cross-coupling.

Fuel cell (FC) test results have been obtained for the first time with the bis-ligand nickel(ii) complex of 1,4-diaza-3,7-diphosphacyclootane heterogeneous catalyst. Using AFM technique the [Ni(PPh...

New cationic octahedral bis-ligand iron (II) complexes of 1,5-diaza-3,7-diphosphacyclooctanes were synthesized as mixtures of two cis-isomers with different mutual arrangement of Fe–P-bonds and co-ligands which may be separated by a fractional crystallization.

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 series of multinuclear Cu(I) complexes (CuI)xLy, namely the previously reported (CuI)6L2 and (CuI)2L′ and novel (CuI)2L2, where L and L′ are 1,5-di(R)-3,7-bis(2-pyridine-2′-yl)ethyl-1,5-diaza-3,7-diphosphacyclooctanes are introduced. Both dissociative and oxidative behavior of the complexes in DMSO and DMF solutions are correlated with the time-dependent changes in their phosphorescence originated from 3(X + M)LCT transitions. The instability of butterfly-like (CuI)2L′ resulting in its oxidative degradation in DMSO and transformation into (CuI)L′2 in DMF solutions differentiates it from more stable linear complexes (CuI)6L2 and (CuI)2L2. The complexes (CuI)2L2 and (CuI)L2 produced by the dissociation of (CuI)6L2.in DMSO and DMF solutions are regarded as structural motifs responsible for both reversible blue-shifting by 10 nm of the emission band and the decrease in the excited states lifetime values upon the heating of the solutions within 293–333 K. This temperature-induced behavior along with the phosphorescence character of the emission of both complexes points to thermally activated delayed fluorescence as the reason for the reversible temperature-induced spectral changes of hexanuclear (CuI)6L2. Smaller nuclearity of (CuI)2L2 is the reason for partial reversibility of the spectral changes.

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.

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.

Cyclic seven-membered bisphosphanes, namely 1-aza-3,6-diphosphacycloheptanes 3–5 (3: 3,6-diphenyl-1-(1-phenylethyl)-1-aza-3,6-diphosphacycloheptane; 4: 1-[(1R)-1-(4′-methoxyphenyl)ethyl]-3,6-diphenyl-1-aza-3,6-diphosphacycloheptane; 5: 3,6-diphenyl-1-[(1R)-1-phenylpropyl]-1-aza-3,6-diphosphacycloheptane), with chiral exocyclic substituents at the nitrogen positions have been synthesized, with the prevailing formation of meso stereoisomers (PRPS) as kinetically controlled products, by stereoselective condensation of 1,2-bis(phenylphosphanyl)ethane, formaldehyde and primary optically pure amines, namely (S)-(–)-1-phenylethylamine, (R)-(+)-1-phenylethylamine, (R)-(+)-1-phenylpropylamine, (R)-(+)-1-(4′-methoxyphenyl)ethylamine. The meso stereoisomers of bisphosphanes 3RSS, 3–5RSR readily form neutral and cationic P,P-chelate complexes 6–9 with platinum(II) (6: cis-dichloro-(3R,6S)-3,6-diphenyl-1-[(1S)-1-phenylethyl]-1-aza-3,6-diphosphacycloheptaneplatinum(II); 7: cis-dichloro-(3R,6S)-1-[(1R)-1-(4′-methoxyphenyl)ethyl]-3,6-diphenyl-1-aza-3,6-diphosphacycloheptaneplatinum(II); 8:bis{(3R,6S)-[(1R)-3,6-diphenyl-1-(1-phenylethyl)-1-aza-3,6-diphosphacycloheptane]}platinum(II) dichloride; 9: bis{(3R,6S)-3,6-diphenyl-1-[(1R)-1-phenylpropyl]-1-aza-3,6-diphosphacycloheptane}platinum(II) dichloride). The fast and selective formation of the cationic complex (9) of the meso isomer 5RSR allowed for the separation of the 5RRR and 5SSR isomers of the bisphosphane 5. In solution, selective stereoconversion of the pure 3RSS, 3RSR and 4RSR isomers into a mixture containing 3RRS, 3SSR and 4SSR stereoisomers as the predominant products was observed. As a result, the stereoconversion is accompanied by a change in not only the value but also in the sign of the specific rotation, [α]D20. The ratio of the stereoisomers in an equilibrium mixture of 3C(S) (3RSS/3RRS/3SSS in a 24:48:28 ratio) is in accord with their relative energies that were calculated with the B3LYP/6-31G* basis. Kinetic studies of the stereoconversion of bisphosphane 3C(S) have been performed. The rate constants that were determined are indicative of a bimolecular interconversion mechanism, which is supposedly the reason for the relatively low activation energies for inversion at phosphorus. Molecular structures were obtained, by X-ray crystal structure analysis, for the meso3RSS and 3RRS stereoisomers of the N-(S)-1-phenylethyl-substituted bisphosphanes and for 4RSR.

A novel type of 14-membered cyclic polyphosphine, namely 1,8-diaza-3,6,10,13-tetraphosphacyclotetradecanes 2a–4a has been synthesized by the condensation of 1,2-bis(phenylphosphino)ethane, formaldehyde and alkylamines (isopropylamine, ethylamine and cyclohexylamine) as a RRRR/SSSS-stereoisomer. The structure of macrocycle 2a was investigated by NMR-spectroscopy and X-ray crystal structure analysis. The unique reversible processes of macrocycles 2a–4a splitting onto the corresponding rac- (2b–4b) and meso- (2c–4c) stereoisomers of 1-aza-3,6-diphosphacycloheptanes were discovered.

Bis-ligand nickel(ii)complex of 1,4 -diaza-3,7-diphosphacyclootanes with phenyl and p-tolyl substituents of nitrogen and phosphorus atoms correspondingly has been found as an oxygen reduction react...

The pyridyl substituted 1,5-diaza-3,7-diphosphacyclooctanes were utilized for the luminescent copper(I) and gold(I) complexes design. The structures of the obtained metal complexes depend on the me...

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.

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.