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Gastric cancer prognosis is still notably poor despite efforts made to improve diagnosis and treatment of the disease. Chemotherapy based on platinum agents is generally used, regardless of the fact that drug toxicity leads to limited clinical efficacy. In order to overcome these problems, our group has been working on the synthesis and study of trans platinum (II) complexes. Here, we explore the potential use of two phosphine-based agents with the general formula trans -[Pt(amine)Cl 2 (PPh 3 )], called P1 and P2 (with dimethylamine or isopropylamine, respectively). A cytotoxicity analysis showed that P1 and especially P2 decrease cell viability. Specifically, P2 exhibits higher activity than cisplatin in gastric cancer cells while its toxicity in healthy cells is slightly lower. Both complexes generate Reactive Oxygen Species, produce DNA damage and mitochondrial membrane depolarization, and finally lead to induced apoptosis. Thus, an intrinsic apoptotic pathway emerges as the main type of cell death through the activation of BAX/BAK and BIM and the degradation of MCL1. Additionally, we demonstrate here that P2 produces endoplasmic reticulum stress and activates the Unfolded Protein Response, which also relates to the impairment observed in autophagy markers such as p62 and LC3. Although further studies in other biological models are needed, these results report the biomolecular mechanism of action of these Pt(II)-phosphine prototypes, thus highlighting their potential as novel and effective therapies.

3,4-disubstituted maleimides find wide applications in various pharmacologically active compounds. This study presents a highly effective approach for synthesizing derivatives of 3,4-disubstituted maleimides through the direct isomerization of α-succinimide-substituted allenoates, followed by a cascade γ'-addition and aryl imines using PR 3 as a catalyst. The resulting series of 3,4-disubstituted maleimides exhibited excellent stereoselectivities, achieving yields of up to 86%. To our knowledge, the phosphine-mediated γ'-addition reaction of allenoates is seldom reported.

The reaction of ( ortho- acetalaryl)arylmethanols with various phosphines PR 1 R 2 R 3 (R 1 = R 2 = R 3 = Ph; R 1 = R 2 = Ph, R 3 = Me and R 1 = R 2 = Me, R 3 = Ph) under acidic conditions (e.g., HCl, HBF 4 , TsOH) unexpectedly led to the formation of (10-hydroxy-9,10-dihydroanthr-9-yl)phosphonium salts instead of the corresponding anthryl phosphonium salts. The cyclization occurred according to the Friedel-Crafts mechanism but without the usually observed Bradsher dehydration, giving cyclic products in the form of cis/trans isomers and their conformers. In case of electron-rich and less-hindered dimethylphenylphosphine, all four stereoisomers were recorded in 31 P{ 1 H} NMR spectra, while for the other phosphines, only the two most stable cis / trans stereoisomers were detected. This study was supported by DFT and NCI calculations in combination with FT-IR analysis.

Reactions of isocyanates/isothiocyanates with primary and secondary phosphines without solvent at room temperature afforded phosphinecarboxamide/phosphinecarbothioamide, respectively, in excellent yields. Furthermore, palladium complex Pd(COD)Cl 2 was allowed to react with Ph 2 PC(O)NHPh ( 1a ) to afford [Pd{Ph 2 PC(O)NHPh-κ P } 2 Cl 2 ] ( 3 ). On the other hand, the reaction of Pd(COD)Cl 2 with 1 eq. of Ph 2 PC(S)NHPh ( 2a ) afforded [PdCl 2 {Ph 2 PC(S)NHPh-κ P,S }] ( 4 ). In the case of a 1:2 molar ratio, [PdCl{Ph 2 PC(S)NHPh-κ P,S }{Ph 2 PC(S)NHPh-κ P }]Cl ( 5 ) was formed. The newly obtained compounds were fully characterized using multielement NMR measurements and elemental analyses. In addition, the molecular structures of Ph 2 PC(O)NH(CH 2 ) 2 Cl ( 1j ), Ph 2 PC(S)NHPh(4-Cl) ( 2c ), and 3 - 5 were determined using single-crystal X-ray diffraction.

A Knoevenagel based redox-reaction promoted by intramolecular phosphine sources is presented for the first time. The influence of different diketones, aldehydes, bases and acids was investigated. The effects of different substituents were evaluated based on their electronical influence on the diketone structure. With the obtained results a mechanism is proposed, giving information about transition states formed during the reaction, which can lead to different products. This type of an internal redox transformation with a phosphine oxide moiety remaining in the molecule after the redox reaction represents a new type of reaction.

Trialkyl and triaryl phosphines are important classes of ligands in the field of catalysis and materials research. The wide usability of these low-valent phosphines has led to the design and development of new synthesis routes for a variety of phosphines. In the present work, we report the synthesis and characterization of some mixed arylalkyl tertiary phosphines via the Grignard approach. A new asymmetric phosphine is characterized extensively by multi-spectroscopic techniques. IR and UV-Vis spectra of some selected compounds are also compared and discussed. Density functional theory (DFT)-calculated results support the formation of the new compounds.

Levulinic acid and its esters (e.g., ethyl levulinate, EL) are platform chemicals derived from biomass feedstocks that can be converted to a variety of valuable compounds. Reductive amination of levulinates with primary amines and H 2 over heterogeneous catalysts is an attractive method for the synthesis of N -alkyl-5-methyl-2-pyrrolidones, which are an environmentally friendly alternative to the common solvent N -methyl-2-pyrrolidone (NMP). In the present work, the catalytic properties of the different nickel phosphide catalysts supported on SiO 2 and Al 2 O 3 were studied in a reductive amination of EL with n -hexylamine to N -hexyl-5-methyl-2-pyrrolidone (HMP) in a flow reactor. The influence of the phosphorus precursor, reduction temperature, reactant ratio, and addition of acidic diluters on the catalyst performance was investigated. The Ni 2 P/SiO 2 catalyst prepared using (NH 4 ) 2 HPO 4 and reduced at 600 °C provides the highest HMP yield, which reaches 98%. Although the presence of acid sites and a sufficient hydrogenating ability are important factors determining the pyrrolidone yield, the selectivity also depends on the specific features of EL adsorption on active catalytic sites.

The analysis of total vitamin C content in food is most frequently performed by reducing dehydroascorbic acid to ascorbic acid, which is then assayed with the technique of high-performance liquid chromatography combined with spectrophotometric detection. Tris(2-carboxyethyl)phosphine is currently the only agent in use that efficiently reduces dehydroascorbic acid at pH < 2. Therefore, there is a continued need to search for new reducing agents that will display a high reactivity and stability in acidic solutions. The objective of the study was to verify the applicability of unithiol and tris(hydroxypropyl)phosphine for a reducing dehydroascorbic acid in an extraction medium with pH < 2. The conducted validation of the newly developed method of determining the total content of vitamin C using tris(hydroxypropyl)phosphine indicates its applicability for food analysis. The method allows obtaining equivalent results compared to the method based on the use of tris(2-carboxyethyl)phosphine. The low efficiency of dehydroascorbic acid reduction with the use of unithiol does not allow its application as a new reducing agent in vitamin C analysis.

Phosphinate pseudopeptide are analogs of peptides containing phosphinate moiety in a place of the amide bond. Due to this, the organophosphorus fragment resembles the tetrahedral transition state of the amide bond hydrolysis. Additionally, it is also capable of coordinating metal ions, for example, zinc or magnesium ions. These two properties of phosphinate pseudopeptides make them an ideal candidate for metal-related protease inhibitors. This research investigates the influence of additional residue in the P2 position on the inhibitory properties of phosphinopeptides. The synthetic strategy is proposed, based on retrosynthetic analysis. The N-C-P bond formation in the desired compounds is conveniently available from the three-component condensation of appropriate amino components, aldehydes, and hypophosphorous acid. One of the crucial synthetic steps is the careful selection of the protecting groups for all the functionals. Determination of the inhibitor activity of the obtained compounds has been done using UV-Vis spectroscopy and standard substrate L -Leu- p -nitroanilide toward the enzymes isolated from the porcine kidney (SsLAP, Sus scrofa Leucine aminopeptidase) and barley seeds (HvLAP, Hordeum vulgare Leucine aminopeptidase). An efficient procedure for the preparation of phosphinotripeptides has been performed. Activity test shown that introduction of additional residue into P2 position obtains the micromolar range inhibitors of SsLAP and HvLAP. Moreover, careful selection of the residue in the P2 position should improve its selectivity toward mammalian and plant leucyl aminopeptidases.

Phosphine-borane complexes are novel chemical entities with preclinical efficacy in neuronal and ophthalmic disease models. In vitro and in vivo studies showed that the metabolites of these compounds are capable of cleaving disulfide bonds implicated in the downstream effects of axonal injury. A difficulty in using standard in silico methods for studying these drugs is that most computational tools are not designed for borane-containing compounds. Using in silico and machine learning methodologies, the absorption-distribution properties of these unique compounds were assessed. Features examined with in silico methods included cellular permeability, octanol-water partition coefficient, blood-brain barrier permeability, oral absorption and serum protein binding. The resultant neural networks demonstrated an appropriate level of accuracy and were comparable to existing in silico methodologies. Specifically, they were able to reliably predict pharmacokinetic features of known boron-containing compounds. These methods predicted that phosphine-borane compounds and their metabolites meet the necessary pharmacokinetic features for orally active drug candidates. This study showed that the combination of standard in silico predictive and machine learning models with neural networks is effective in predicting pharmacokinetic features of novel boron-containing compounds as neuroprotective drugs.

Dendrimers are hyperbranched macromolecules, which are synthesized step-by-step by the repetition of a series of reactions. While many different types of dendrimers are known, this review focusses on the use of trivalent phosphorus derivatives (essentially phosphines and phosphoramidites) for the synthesis of dendrimers. The first part presents dendrimers constituted of phosphines at each branching point. The other parts display the use of trivalent phosphorus derivatives during the synthesis of dendrimers. Different types of reactions have been applied to phosphines. The very first examples of phosphorus-containing dendrimers were obtained by the alkylation of phosphines. Then, several families of dendrimers were elaborated by reaction of phosphoramidites. Such a type of reaction is the base of the solid phase synthesis of oligonucleotides; it has been applied in particular for the synthesis of dendrimers constituted of oligonucleotides. Finally, the Staudinger reaction between phosphines and azides afforded different families of dendrimers, and was at the origin of accelerated methods of synthesis of dendrimers. Besides, the reactivity of the P=N-P=S linkages created by this reaction led to very original dendritic structures.

The preparation, characterization and electrochemical and photophysical properties of a series of desymmetrized heteroleptic [Cu(P^P)(N^N)][PF 6 ] compounds are reported. The complexes incorporate the chelating P^P ligands bis(2-(diphenylphosphanyl)phenyl)ether (POP) and (9,9-dimethyl-9 H -xanthene-4,5-diyl)bis(diphenylphosphane) (xantphos), and 6-substituted 2,2'-bipyridine (bpy) derivatives with functional groups attached by -(CH 2 ) n - spacers: 6-(2,2'-bipyridin-6-yl)hexanoic acid ( 1 ), 6-(5-phenylpentyl)-2,2'-bipyridine ( 2 ) and 6-[2-(4-phenyl-1 H -1,2,3,triazol-1-yl)ethyl]-2,2'-bipyridine ( 3 ). [Cu(POP)( 1 )][PF 6 ], [Cu(xantphos)( 1 )][PF 6 ], [Cu(POP)( 2 )][PF 6 ], [Cu(xantphos)( 2 )][PF 6 ], and [Cu(xantphos)( 3 )][PF 6 ] have been characterized in solution using multinuclear NMR spectroscopy, and the single crystal structure of [Cu(xantphos)( 3 )][PF 6 ] . 0.5Et 2 O was determined. The conformation of the 6-[2-(4-phenyl-1 H -1,2,3,triazol-1-yl)ethyl]-substituent in the [Cu(xantphos)( 3 )] + cation is such that the α- and β-CH 2 units reside in the xanthene 'bowl' of the xantphos ligand. The 6-substituent desymmetrizes the structure of the [Cu(P^P)(N^N)] + cation and this has consequences for the interpretation of the solution NMR spectra of the five complexes. The NOESY spectra and EXSY cross-peaks provide insight into the dynamic processes operating in the different compounds. For powdered samples, emission maxima are in the range 542-555 nm and photoluminescence quantum yields (PLQYs) lie in the range 13-28%, and a comparison of PLQYs and decay lifetimes with those of [Cu(xantphos)(6-Mebpy)][PF 6 ] indicate that the introduction of the 6-substituent is not detrimental in terms of the photophysical properties.

The mechanism of the carbonylation of diazomethane in the presence of iron-carbonyl-phosphine catalysts has been investigated by means of DFT calculations at the M06/def-TZVP//B97D3/def2-TZVP level of theory, in combination with the SMD solvation method. The reaction rate is determined by the formation of the coordinatively unsaturated doublet-state Fe(CO) 3 (P) precursor followed by the diazoalkane coordination and the N 2 extrusion. The free energy of activation is predicted to be 18.5 and 28.2 kcal/mol for the PF 3 and PPh 3 containing systems, respectively. Thus, in the presence of less basic P-donor ligands with stronger π-acceptor properties, a significant increase in the reaction rate can be expected. According to energy decomposition analysis combined with natural orbitals of chemical valence (EDA-NOCV) calculations, diazomethane in the Fe(CO) 3 (phosphine)( η 1 -CH 2 N 2 ) adduct reveals a π-donor-π-acceptor type of coordination.

The 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA) derivatives, viz. the already reported 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane 5-oxide (DAPTA=O, 1 ), the novel 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane-5-sulfide (DAPTA=S, 2 ), and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane-5-selenide (DAPTA=Se, 3 ), have been synthesized under mild conditions. They are soluble in water and most common organic solvents and have been characterized using 1 H and 31 P NMR spectroscopy and, for 2 and 3 , also by single crystal X-ray diffraction. The effect of O, S, or Se at the phosphorus atom on the structural features of the compounds has been investigated, also through the analyses of Hirshfeld surfaces. The presence of 1 - 3 enhances the activity of copper for the catalytic azide-alkyne cycloaddition reaction in an aqueous medium. The combination of cheaply available copper (II) acetate and compound 1 has been used as a catalyst for the one-pot and 1,4-regioselective procedure to obtain 1,2,3-triazoles with high yields and according to 'click rules'.

A series of neutral mixed-ligand [HB(pz) 3 ]Ag(PR 3 ) silver(I) complexes (PR 3 = tertiary phosphine, [HB(pz) 3 ] - = tris(pyrazolyl)borate anion), and the corresponding homoleptic [Ag(PR 3 ) 4 ]BF 4 compounds have been synthesized and fully characterized. Silver compounds were screened for their antiproliferative activities against a wide panel of human cancer cells derived from solid tumors and endowed with different platinum drug sensitivity. Mixed-ligand complexes were generally more effective than the corresponding homoleptic derivatives, but the most active compounds were [HB(pz) 3 ]Ag(PPh 3 ) ( 5 ) and [Ag(PPh 3 ) 4 ]BF 4 ( 10 ), both comprising the lipophilic PPh 3 phosphine ligand. Detailed mechanistic studies revealed that both homoleptic and heteroleptic silver complexes strongly and selectively inhibit the selenoenzyme thioredoxin reductase both as isolated enzyme and in human ovarian cancer cells (half inhibition concentration values in the nanomolar range) causing the disruption of cellular thiol-redox homeostasis, and leading to apoptotic cell death. Moreover, for heteroleptic Ag(I) derivatives, an additional ability to damage nuclear DNA has been detected. These results confirm the importance of the type of silver ion coordinating ligands in affecting the biological behavior of the overall corresponding silver complexes, besides in terms of hydrophilic-lipophilic balance, also in terms of biological mechanism of action, such as interaction with DNA and/or thioredoxin reductase.

Bulk GaPO 4 is an advanced piezoelectric material operating under high temperatures according to the α-β phase transition at 970 °C. This work presents the technological development of a hydrothermal refluxing method first applied for GaPO 4 single crystal growth. Crystals of 10-20 g were grown in mixtures of aqueous solutions of low- and high-vapor-pressure acids (H 3 PO 4 /HCl) at 180-240 °C (10-20 bars). The principal feature of the refluxing method is a spatial separation of crystal growth and nutrient dissolution zones. This leads to a constant mass transportation of the dissolved nutrient, even for materials with retrograde solubility. Mass transport is carried out by dissolution of GaPO 4 nutrient in a dropping flow of condensed low-vapor-pressure solvent. This method allows an exact saturation at temperature of equilibrium and avoids spontaneous crystallization as well loss of seeds. Grown crystals have a moderate OH - content and reasonable structural uniformity. Moreover, the hydrothermal refluxing method allows a fine defining of GaPO 4 concentration in aqueous solutions of H 3 PO 4 , H 2 SO 4 , HCl and their mixtures at set T-P parameters (T < 250 °C, p = 10-30 bars). The proposed method is relatively simple to use, highly reproducible for crystal growth of GaPO 4 and probably could applied to other compounds with retrograde solubility.

InP QDs have shown a great potential as cadmium-free QDs alternatives in biomedical applications. It is essential to understand the biological fate and toxicity of InP QDs. In this study, we investigated the in vivo renal toxicity of InP/ZnS QDs terminated with different functional groups-hydroxyl (hQDs), amino (aQDs) and carboxyl (cQDs). After a single intravenous injection into BALB/c mice, blood biochemistry, QDs distribution, histopathology, inflammatory response, oxidative stress and apoptosis genes were evaluated at different predetermined times. The results showed fluorescent signals from QDs could be detected in kidneys during the observation period. No obvious changes were observed in histopathological detection or biochemistry parameters. Inflammatory response and oxidative stress were found in the renal tissues of mice exposed to the three kinds of QDs. A significant increase of KIM-1 expression was observed in hQDs and aQDs groups, suggesting hQDs and aQDs could cause renal involvement. Apoptosis-related genes (Bax, Caspase 3, 7 and 9) were up-regulated in hQDs and aQDs groups. The above results suggested InP/ZnS QDs with different surface chemical properties would cause different biological behaviors and molecular actions in vivo. The surface chemical properties of QDs should be fully considered in the design of InP/ZnS QDs for biomedical applications.

This work reports a straightforward regioselective synthetic methodology to prepare α-aminophosphine oxides and phosphonates through the addition of oxygen and sulfur nucleophiles to the C-N double bond of 2 H -azirine derivatives. Determined by the nature of the nucleophile, different α-aminophosphorus compounds may be obtained. For instance, aliphatic alcohols such as methanol or ethanol afford α-aminophosphine oxide and phosphonate acetals after N-C3 ring opening of the intermediate aziridine. However, addition of 2,2,2-trifluoroethanol, phenols, substituted benzenthiols or ethanethiol to 2 H -azirine phosphine oxides or phosphonates yields allylic α-aminophosphine oxides and phosphonates in good to high general yields. In some cases, the intermediate aziridine attained by the nucleophilic addition of O - or S -nucleophiles to the starting 2 H -azirine may be isolated and characterized before ring opening. Additionally, the cytotoxic effect on cell lines derived from human lung adenocarcinoma (A549) and non-malignant cells (MCR-5) was also screened. Some α-aminophosphorus derivatives exhibited very good activity against the A549 cell line in vitro. Furthermore, selectivity towards cancer cell (A549) over non-malignant cells (MCR-5) has been detected in almost all compounds tested.

The crystal structure of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide ( 1 ) contains two independent molecules in the asymmetric unit. Although the molecules are virtually identical in all other aspects, the P=O bond distances differ by ca. 0.02 Å. In contrast, although tris(pentafluorophenyl)phosphine oxide ( 2 ) has a similar crystal structure, the P=O bond distances of the two independent molecules are identical. To investigate the reason for the difference, a density functional theory study was undertaken. Both structures comprise chains of molecules. The attraction between molecules of 1 , which comprises lone pair-π, weak hydrogen bonding and C-H∙∙∙arene interactions, has energies of 70 and 71 kJ mol -1 . The attraction between molecules of 2 comprises two lone pair-π interactions, and has energies of 99 and 100 kJ mol -1 . There is weak hydrogen bonding between molecules of adjacent chains involving the oxygen atom of 1 . For one molecule, this interaction is with a symmetry independent molecule, whereas for the other, it also occurs with a symmetry related molecule. This provides a reason for the difference in P=O distance. This interaction is not possible for 2 , and so there is no difference between the P=O distances of 2 .

The synthesis and structural characterization of 5,6'-dimethyl-2,2'-bipyridine (5,6'-Me 2 bpy) are reported, along with the preparations and characterizations of [Cu(POP)(5,6'-Me 2 bpy)][PF 6 ] and [Cu(xantphos)(5,6'-Me 2 bpy)][PF 6 ] (POP = bis(2-(diphenylphosphanyl)phenyl)ether, xantphos = 4,5-bis(diphenylphosphanyl)-9,9-dimethyl-9 H -xanthene). Single-crystal X-ray structure determinations of [Cu(POP)(5,6'-Me 2 bpy)][PF 6 ] and [Cu(xantphos)(5,6'-Me 2 bpy)][PF 6 ] confirmed distorted tetrahedral copper(I) coordination environments with the 5-methylpyridine ring of 5,6'-Me 2 bpy directed towards the (C 6 H 4 ) 2 O unit of POP or the xanthene unit of xantphos. In the xantphos case, this preference may be attributed to C-H…π interactions involving both the 6-CH unit and the 5-methyl substituent in the 5-methylpyridine ring and the arene rings of the xanthene unit. 1 H NMR spectroscopic data indicate that this ligand orientation is also preferred in solution. In solution and the solid state, [Cu(POP)(5,6'-Me 2 bpy)][PF 6 ] and [Cu(xantphos)(5,6'-Me 2 bpy)][PF 6 ] are yellow emitters, and, for powdered samples, photoluminescence quantum yields (PLQYs) are 12 and 11%, respectively, and excited-state lifetimes are 5 and 6 μs, respectively. These values are lower than PLQY and τ values for [Cu(POP)(6,6'-Me 2 bpy)][PF 6 ] and [Cu(xantphos)(6,6'-Me 2 bpy)][PF 6 ], and the investigation points to the 6,6'-dimethyl substitution pattern in the bpy ligand being critical for enhancement of the PLQY.

Hydrogen-bonded heterocomplexes formed by POOH-containing acids (diphenylphosphoric 1 , dimethylphosphoric 2 , diphenylphosphinic 3 , and dimethylphosphinic 4 ) are studied by the low-temperature (100 K) 1 H-NMR and 31 P-NMR using liquefied gases CDF 3 /CDF 2 Cl as a solvent. Formation of cyclic dimers and cyclic trimers consisting of molecules of two different acids is confirmed by the analysis of vicinal H/D isotope effects (changes in the bridging proton chemical shift, δH, after the deuteration of a neighboring H-bond). Acids 1 and 4 (or 1 and 3 ) form heterotrimers with very strong (short) H-bonds (δH ca. 17 ppm). While in the case of all heterotrimers the H-bonds are cyclically arranged head-to-tail, ···O=P-O-H···O=P-O-H···, and thus their cooperative coupling is expected, the signs of vicinal H/D isotope effects indicate an effective anticooperativity, presumably due to steric factors: when one of the H-bonds is elongated upon deuteration, the structure of the heterotrimer adjusts by shortening the neighboring hydrogen bonds. We also demonstrate the formation of cyclic tetramers: in the case of acids 1 and 4 the structure has alternating molecules of 1 and 4 in the cycle, while in case of acids 1 and 3 the cycle has two molecules of 1 followed by two molecules of 3 .

Carbazole structures are of high interest in photopolymerization due to their enhanced light absorption properties in the near-UV or even visible ranges. Therefore, type I photoinitiators combining the carbazole chromophore to the well-established phosphine-oxides were proposed and studied in this article. The aim of this article was to propose type I photoinitiators that can be more reactive than benchmark phosphine oxides, which are among the more reactive type I photoinitiators for a UV or near-UV light emitting diodes (LED) irradiation. Two molecules were synthesized and their UV-visible light absorption properties as well as the quantum yields of photolysis and photopolymerization performances were measured. Remarkably, the associated absorption was enhanced in the 350-410 nm range compared to benchmark phosphine oxides, and one compound was found to be more reactive in photopolymerization than the commercial photoinitiator TPO-L for an irradiation at 395 nm.

In an effort to explain the experimentally observed variation of the photocatalytic activity of t Bu 3 P, n Bu 3 P and (MeO) 3 P in the blue-light regime [Helmecke et al., Org. Lett. 21 (2019) 7823], we have explored the absorption characteristics of several phosphine- and phosphite-IC 4 F 9 adducts by means of relativistic density functional theory and multireference configuration interaction methods. Based on the results of these computational and complementary experimental studies, we offer an explanation for the broad tailing of the absorption of t Bu 3 P-IC 4 F 9 and (MeO) 3 P-IC 4 F 9 into the visible-light region. Larger coordinate displacements of the ground and excited singlet potential energy wells in n Bu 3 P-IC 4 F 9 , in particular with regard to the P-I-C bending angle, reduce the Franck-Condon factors and thus the absorption probability compared to t Bu 3 P-IC 4 F 9 . Spectroscopic and computational evaluation of conformationally flexible and locked phosphites suggests that the reactivity of (MeO) 3 P may be the result of oxygen lone-pair participation and concomitant broadening of absorption. The proposed mechanism for the phosphine-catalyzed homolytic C-I cleavage of perfluorobutane iodide involves S 1 ← S 0 absorption of the adduct followed by intersystem crossing to the photochemically active T 1 state.

An extensive series of 128 halogen-bonded complexes formed by trimethylphosphine oxide and various F-, Cl-, Br-, I- and At-containing molecules, ranging in energy from 0 to 124 kJ/mol, is studied by DFT calculations in vacuum. The results reveal correlations between R-X⋅⋅⋅O=PMe 3 halogen bond energy Δ E , X⋅⋅⋅O distance r , halogen's σ-hole size, QTAIM parameters at halogen bond critical point and changes of spectroscopic parameters of phosphine oxide upon complexation, such as 31 P NMR chemical shift, Δ δ P, and P=O stretching frequency, Δν. Some of the correlations are halogen-specific, i.e., different for F, Cl, Br, I and At, such as Δ E ( r ), while others are general, i.e., fulfilled for the whole set of complexes at once, such as Δ E (Δ δ P). The proposed correlations could be used to estimate the halogen bond properties in disordered media (liquids, solutions, polymers, glasses) from the corresponding NMR and IR spectra.

Modern solid-state NMR techniques offer a wide range of opportunities for the structural characterization of frustrated Lewis pairs (FLPs), their aggregates, and the products of cooperative addition reactions at their two Lewis centers. This information is extremely valuable for materials that elude structural characterization by X-ray diffraction because of their nanocrystalline or amorphous character, (pseudo-)polymorphism, or other types of disordering phenomena inherent in the solid state. Aside from simple chemical shift measurements using single-pulse or cross-polarization/magic-angle spinning NMR detection techniques, the availability of advanced multidimensional and double-resonance NMR methods greatly deepened the informational content of these experiments. In particular, methods quantifying the magnetic dipole-dipole interaction strengths and indirect spin-spin interactions prove useful for the measurement of intermolecular association, connectivity, assessment of FLP-ligand distributions, and the stereochemistry of adducts. The present review illustrates several important solid-state NMR methods with some insightful applications to open questions in FLP chemistry, with a particular focus on supramolecular associates.

A family of complexes of the formula trans -[RuCl 2 (L)(R-pybox)] (R-pybox = ( S , S )- i Pr-pybox, ( R , R )-Ph-pybox, L = monodentate phosphonite, PPh(OR) 2 , and phosphinite, L = PPh 2 (OR), ligands) were screened in the catalytic asymmetric transfer hydrogenation of acetophenone, observing a strong influence of the nature of both the R-pybox substituents and the L ligand in the process. The best results were obtained with complex trans -[RuCl 2 {PPh 2 (OEt)}{( R , R )-Ph-pybox}] ( 2c ), which provided high conversion and enantioselectivity (up to 96% enantiomeric excess, e.e. ) for the reduction of a variety of aromatic ketones, affording the ( S )-benzylalcohols.

The reactions of the PMe 3 adduct of the silylated germylene [(Me 3 Si) 3 Si] 2 Ge: with GeCl 2 ·dioxane were found to yield 1,1-migratory insertion products of GeCl 2 into one or two Ge-Si bonds. In a related reaction, a germylene was inserted with tris(trimethylsilyl)silyl and vinyl substituents into a Ge-Cl bond of GeCl 2 . This was followed by intramolecular trimethylsilyl chloride elimination to another cyclic germylene PMe 3 adduct. The reaction of the GeCl 2 mono-insertion product (Me 3 Si) 3 SiGe:GeCl 2 Si(SiMe 3 ) 3 with Me 3 SiC≡CH gave a mixture of alkyne mono- and diinsertion products. While the reaction of a divinylgermylene with GeCl 2 ·dioxane only results in the exchange of the dioxane of GeCl 2 against the divinylgermylene as base, the reaction of [(Me 3 Si) 3 Si] 2 Ge: with one GeCl 2 ·dioxane and three phenylacetylenes gives a trivinylated germane with a chlorogermylene attached to one of the vinyl units., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

A straightforward method for the preparation of trisphosphinite ligands in one step, using only commercially available reagents (1,1,1-tris(4-hydroxyphenyl)ethane and chlorophosphines) is described. We have made use of this approach to prepare a small family of four trisphosphinite ligands of formula [CH 3 C{(C 6 H 4 OR 2 ) 3 ], where R stands for Ph ( 1a ), Xyl ( 1b , Xyl = 2,6-Me 2 -C 6 H 3 ), i Pr ( 1c ), and Cy ( 1d ). These polyfunctional phosphinites allowed us to investigate their coordination chemistry towards a range of late transition metal precursors. As such, we report here the isolation and full characterization of a number of Au(I), Ag(I), Cu(I), Ir(III), Rh(III) and Ru(II) homotrimetallic complexes, including the structural characterization by X-ray diffraction studies of six of these compounds. We have observed that the flexibility of these trisphosphinites enables a variety of conformations for the different trimetallic species.

Tri- or tetrasubstituted furans have been prepared from terminal activated olefins and acyl chlorides or anhydrides by a multicomponental convergent synthesis mode. Instead of stoichiometric n Bu 3 P, only catalytic n Bu 3 P or n Bu 3 P=O is needed to furnish the furans in modest to excellent yields with a good functional group tolerance under the aid of reducing agent silane. This synthetic method features a silane-driven catalytic intramolecular Wittig reaction as a key annulation step and represents the first successful application of catalytic Wittig reaction in multicomponent cascade reaction.

Despite the recurrence of aurophilic interactions in the solid-state structures of gold(I) compounds, its rational control, modulation, and application in the generation of functional supramolecular structures is an area that requires further development. The ligand effects over the aurophilic-based supramolecular structures need to be better understood. This paper presents the supramolecular structural diversity of a series of new 1,3-bis(diphenylphosphane)propane (dppp) gold(I) fluorinated thiolates with the general formula [Au 2 (SR F ) 2 (μ-dppp)] (SR F = SC 6 F 5 ( 1 ); SC 6 HF 4 -4 ( 2 ); SC 6 H 3 (CF 3 ) 2 -3,5 ( 3 ); SC 6 H 4 CF 3 -2 ( 4 ); SC 6 H 4 CF 3 -4 ( 5 ); SC 6 H 3 F 2 -3,4 ( 6 ); SC 6 H 3 F 2 -3,5 ( 7 ); SC 6 H 4 F-2 ( 8 ); SC 6 H 4 F-3 ( 9 ); SC 6 H 4 F-4 ( 10 )). These compounds were synthesized and characterized, and six of their solid-state crystalline structures were determined using single-crystal X-ray diffraction. In the crystalline arrangement, they form aurophilic-bridged polymers. In these systems, the changes in the fluorination patterns of the thiolate ligands tune the aurophilic-induced self-assembly of the compounds causing tacticity and chiral differentiation of the monomers. This is an example of the use of ligand effects on the tune of the supramolecular association of gold complexes.

H -phosphonates, H -phosphinates and secondary phosphine oxides may be preligands, and are important building blocks in the synthesis of pharmaceuticals, pesticides, and P -ligands. The prototropic tautomerism influenced by substituent effects plays an important role in the reactivity of these species. The main goal of our research was to study the tautomerism of the >P(O)H reagents by means of computational investigations applying several DFT methods at different levels. We focused on the effect of implicit solvents, and on explaining the observed trends with physical chemical molecular descriptors. In addition, multiple reaction pathways incorporating three P -molecules were elucidated for the mechanism of the interconversion.

Monovalent NHC-nickel complexes bearing triarylphosphine, in which fluorine is incorporated onto the aryl groups, have been synthesized. Tris(3,5-di(trifluoromethyl)-phenyl)phosphine efficiently gave a monovalent nickel bromide complex, whose structure was determined by X-ray diffraction analysis for the first time. In the solid state, the Ni(I) complex was less susceptible to oxidation in air than the triphenylphosphine complex, indicating greatly improved solid-state stability. In contrast, the Ni(I) complex in solution can easily liberate the phosphine, high catalytic activity toward the Kumada-Tamao-Corriu coupling of aryl bromides., Competing Interests: The authors declare no conflict of interest.

Two novel cobalt diphenylphosphine complexes were synthesized by reacting cobalt(II) chloride with tert -butyl(diphenyl)phosphine (P t BuPh 2 ) and ( S )-(+)neomenthyldiphenylphosphine [( S )-NMDPP]. The crystal structure of the former was determined by single-crystal X-ray diffraction studies. The two complexes were then used in combination with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene: crystalline highly syndiotactic 1,2 poly(1,3-butadiene)s were obtained, with a 1,2 content and a syndiotactic index (percentage of syndiotactic triads [ rr ]) up to 95% and 85%, respectively. The results obtained further support and confirm what was already observed in the polymerization of 1,3-butadiene with CoCl 2 (PRPh 2 ) 2 -MAO (R = methyl, ethyl, normal -propyl, iso -propyl, and cyclohexyl): the nature of the phosphine ligand strongly affects the polymerization stereoselectivity, the polymer syndiotacticity increasing with increasing phosphine ligand steric hindrance.

GC20, a novel soluble bis-chelated gold(I)-diphosphine compound, has been reported as a promising anticancer candidate. Assessing the pharmacokinetic properties of GC20 is critical for its medicinal evaluation. First, a sensitive and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and well validated to determine GC20 in rat plasma and rat tissue homogenate after one step protein precipitation. Chromatographic separation was achieved on an Angilent ZORBAX-C18 column (3.5 μm, 2.1 × 50 mm) with gradient elution and mass spectrometry was performed on a triple quadrupole in positive ion mode using an electrospray ionization source. This method was then applied to investigate the pharmacokinetics and tissue distribution of GC20 in rats after intravenous administration. The results showed that the plasma exposure of GC20 in vivo increased with increasing doses after a single dose. However, after multiple doses, a significant accumulation and a saturation at elimination were observed for GC20 in rats. Moreover, after intravenous administration, GC20 was widely distributed in various tissues, with the highest levels in the lung, spleen, liver, and pancreas, followed by the kidney and heart, while the lowest level was found in the brain. This is the first report on the pharmacokinetic properties of GC20.

Herein, we report the homo- and co-polymerization of ethylene (E) with norbornene (NB) catalyzed by vanadium(III) phosphine complexes of the type VCl 3 (PMe n Ph 3-n ) 2 [n = 2 ( 1a ), 1 ( 1b )] and VCl 3 (PR 3 ) 2 [R = phenyl (Ph, 1c ), cyclohexyl (Cy, 1d ), tert -butyl ( t Bu, 1e )]. In the presence of Et 2 AlCl and Cl 3 CCOOEt (ETA), 1a - 1e exhibit good activities for the polymerization of ethylene, affording linear, semicrystalline PEs with a melting temperature of approximately 130 °C. Mainly alternating copolymers with high comonomer incorporation were obtained in the E/NB copolymerization. A relationship was found between the electronic and steric properties of the phosphine ligands and the catalytic performance. Overall, the presence of electron-withdrawing ligand substituents increases the productivity, complexes with aryl phosphine (weaker σ-donor character) exhibiting a higher (co)polymerization initiation rate than those with alkyl phosphines (stronger σ-donor character). Steric effects also seem to play a key role since 1d and 1e , having large size phosphines (PCy 3 θ = 170° and P t Bu 3 θ = 182°, respectively) are more active than 1a (PMe 2 Ph θ = 122°). In this case, the larger size of P t Bu 3 and PCy 3 likely compensates for their higher donor strength compared to PMe 2 Ph.

A series of indane-based phosphine-oxazoline ligands with a spirocarbon stereogenic center were examined for palladium-catalyzed asymmetric allylic alkylation of indoles. Under optimized conditions, high yields (up to 98%) and enantioselectivities (up to 98% ee) were obtained with a broad scope of indole derivatives. The ligand was determined to be the most efficient P,N-ligand for this reaction. Moreover, the ligand was also efficient for Pd-catalyzed asymmetric allylic etherification with hard aliphatic alcohols as nucleophiles.

A class of gold(I) phosphane complexes have been identified as inhibitors of dihydrofolate reductase (DHFR) from E. coli , an enzyme that catalyzes the reduction of dihydrofolate (DHF) to tetrahydrofolate (THF), using NADPH as a coenzyme. In this work, to comprehend the nature of the interaction at the basis of these inhibitory effects, the binding properties of bis- and tris-phosphane gold(I) chloride compounds in regards to DHFR have been studied by emission spectroscopy and spectrophotometric assays. The lack of cysteine and seleno-cysteine residues in the enzyme active site, the most favorable sites of attack of Au(I) moieties, makes this work noteworthy. The interaction with the gold compounds results into the quenching of the DHFR tryptophan's emissions and in an enhancement of their intrinsic emission intensities. Moreover, a modulating action of NADPH is highlighted by means of an increase of the gold compound affinity toward the enzyme; in fact, the dissociation constants calculated for the interactions between DHFR and each gold compound in the presence of saturating NADPH were lower than the ones observed for the apo-enzyme. The fluorimetric data afforded to K d values ranged from 2.22 ± 0.25 µM for (PPh₃)₂AuCl in the presence of NADPH to 21.4 ± 3.85 µM for ⁴L₃AuTf in the absence of NADPH. By elucidating the energetic aspects of the binding events, we have attempted to dissect the role played by the gold phosphane/protein interactions in the inhibitory activity, resulting in an exothermic enthalpy change and a positive entropic contribution (ΔH° = -5.04 ± 0.08 kcal/mol and ΔS° = 7.34 ± 0.005 cal/mol·K).

A simple, highly efficient synthesis of a series of novel chiral non-racemic rigid tetracyclic phosphorus ligands, applicable in important chemical asymmetric transformations, was performed. In a tandem cross-coupling/C-H bond activation reaction, a well-recognised and readily available ligand (R,R)- NORPHOS was used as the starting material. The palladium complexes of new ligands were obtained and characterised on the example of a crystalline dichloropalladium complex of [(1 R ,2 R ,9 S ,10 S ,11 R ,12 R )-4-phenyltetracyclo[8.2.1.0 2,9 .0 3,8 ]trideca-3,5,7-triene-11,12-diyl]bis(diphenylphosphane). A notably high activity and stereoselectivity of the palladium catalysts based on the new ligands were confirmed in a model asymmetric allylic substitution reaction. Herein, we discuss the geometry of the palladium complexes formed and its impact on the efficiency of the catalysts. A comparison of their geometric features with other bis(phosphane) ligand complexes found in the Cambridge Structural Database and built density functional theory (DFT) commutated models is also presented and rationalised.

The applicability of two types of transition-metal carbonyl complexes as appropriate candidates for computationally derived Tolman's ligand electronic parameters were examined with density functional theory (DFT) calculations employing the B97D3 functional. Both Pd (0) L2(CO) and HRh (I) L2(CO) complexes correlated well with the experimental Tolman Electronic Parameter scale. For direct comparison of the electronic effects of diphosphines with those of monophosphines, the palladium-containing system is recommended. The t r a n s influence of various phosphines did not show a major difference, but the decrease of the H-Rh-P angle from linear can cause a significant change.

In recent years, there have been extraordinary developments of organophosphine-catalyzed reactions. This includes progress in the area of [4C+X] annulations, which are of particular interest due to their potential for the rapid construction of 5⁻8-membered cyclic products. In this short overview, we summarize the remarkable progress, emphasizing reaction mechanisms and key intermediates involved in the processes. The discussion is classified according to the type of electrophilic reactants that acted as C ₄ synthons in the annulation process, in the order of α-alkyl allenoates, γ-alkyl allenoates, α-methyl allene ketones, β'-OAc allenoate, δ-OAc allenoate, activated dienes and cyclobutenones.

The development and optimization of synthetic methods leading to functionalized biologically active compounds is described. Two alternative pathways based on Heck-type reactions, employing iodobenzene or phenylboronic acid, were elaborated for the arylation of eugenol and estragole. Cinnamyl alcohol was efficiently transformed to saturated arylated aldehydes in reaction with iodobenzene using the tandem arylation/isomerization sequential process. The arylation of cinnamyl alcohol with phenylboronic acid mainly gave unsaturated alcohol, while the yield of saturated aldehyde was much lower. Catalytic reactions were carried out using simple, phosphine-free palladium precursors and water as a cosolvent, following green chemistry rules as much as possible.

A symmetrical flexible bis(phosphinoferrocene) derivative, viz. bis[1'-(diphenylphosphino)ferrocenyl]methane ( 1 ), was prepared and studied as a ligand in Pd(II) and Au(I) complexes. The reactions of 1 with [PdCl₂(cod)] (cod = cycloocta-1,5-diene) and [Pd(μ-Cl)(L NC )]₂ (L NC = [2-(dimethylamino-κ N )methyl]phenyl-κ C ¹) produced bis(phosphine) complex trans -[PdCl₂( 1 -κ²P,P')] ( 4 ), wherein the ligand spans trans positions in the square-planar coordination sphere of Pd(II) and the tetranuclear, P,P-bridged complex [(μ(P,P')- 1 ){PdCl(L NC )}₂] ( 5 ), respectively. In reactions with the Au(I) precursors [AuCl(tht)] and [Au(tht)₂][SbF₆] (tht = tetrahydrothiophene), ligand 1 gave rise to tetranuclear Au₂Fe₂ complex [(μ(P,P')- 1 )(AuCl)₂] ( 6 ) and to symmetrical macrocyclic tetramer [Au₄(μ(P,P')- 1 )₄][SbF₆]₄ ( 7 ). All compounds were characterized by spectroscopic methods. In addition, the structures of compound 1 , its synthetic precursor bis[1'-(diphenylphosphino)ferrocenyl]methanone ( 3 ), and all aforementioned Pd(II) and Au(I) complexes were determined by single-crystal X-ray diffraction analysis (some in solvated form).

An efficient and practical approach towards bifunctional phosphorus phenols has been developed through a reaction of diphenylphosphine oxide and the o -quinone methides in situ generated from 2-tosylalkyl phenols under basic conditions. This protocol features simple experimental procedures under mild conditions and is easily scaled up. With this method, a variety of diarylmethyl phosphine oxides can be produced with up to 92% yield.

Buchwald-Hartwig-Migita cross-coupling of 1-thiosugars with α- or β-3-iodo-N-glycosylquinolin-2-ones has been accomplished under mild and operationally simple reaction conditions through the use of a Pd-G3 XantPhos palladacycle precatalyst. This new methodology has been successfully applied to a variety of α- or β-mono-, di-, and poly-thiosugar derivatives to efficiently synthesize a series of α- or β-N,S-bis-glycosyl quinolin-2-ones, which are difficult to synthesize by classical methods., Competing Interests: The authors declare no conflict of interest.

This work reports the chemoselective polymerization of polar divinyl monomers, including allyl methacrylate (AMA), vinyl methacrylate (VMA), and 4-vinylbenzyl methacrylate (VBMA), by using simple Lewis pairs comprised of homoleptic rare-earth (RE) aryloxide complexes RE(OAr)₃ (RE = Sc ( 1 ), Y ( 2 ), Sm ( 3 ), La ( 4 ), Ar = 2,6- t Bu₂C₆H₃) and phosphines PR₃ (R = Ph, Cy, Et, Me). Catalytic activities of polymerizations relied heavily upon the cooperation of Lewis acid and Lewis base components. The produced polymers were soluble in common organic solvents and often had a narrow molecular weight distribution. A highly syndiotactic poly(allyl methacrylate) (PAMA) with rr ~88% could be obtained by the scandium complex 1 /PEt₃ pair at -30 °C. In the case of poly(4-vinylbenzyl methacrylate) (PVBMA), it could be post-functionalized with PhCH₂SH. Mechanistic study, including the isolation of the zwitterionic active species and the end-group analysis, revealed that the frustrated Lewis pair (FLP)-type addition was the initiating step in the polymerization., Competing Interests: The authors declare no conflict of interest.

A series of lithium complexes ([Ph₂P( o -C₆H₄-CH₂Li·TMEDA)] ( 1-Li ), [PhP( o -C₆H₄-CH₃)( o -C₆H₄-CH₂Li·TMEDA)] ( 2-Li ), [PhP( o -C₆H₄-CH₂Li·TMEDA)₂] ( 2-Li₂ ) and [P( o -C₆H₄-CH₂Li·TMEDA)₃] ( 3-Li₃ )) was prepared from mono-, di- and tri-benzylphosphines and varying amounts of n BuLi and was characterized extensively by IR and ¹H, ⁷Li, 13 C and 31 P NMR spectroscopy. The molecular structures of complexes 1-Li and 2-Li were determined by single-crystal X-ray diffraction studies. The two complexes have monomeric structures in the solid state comprising seesaw lithium atoms. In each case, the ligand exhibits an asymmetric C-C η²-coordination mode and an intramolecular P-Li bond interaction. Theoretical calculations at Density functional theory (DFT) level M06/6111+G(2d,p) show that indeed a P-Li bond is established which can be explained as the P lone pair ( sp 1.26 ) being partially delocalized on an available sp ² orbital on Li ( sp 2.04 ) and additional bonding contribution of the phosphorous atom to Li stems from further delocalization of a σ P-C orbital into the sp ² orbital on Li. The observed short contact distances between an aromatic ipso carbon and Li in the crystal structures of 1-Li and 2-Li are explained as due to the interaction of a σ C-Li orbital into the π* orbital of a C-C aromatic bond. Preliminary tests show compounds 1-Li , 2-Li , 2-Li₂ and 3-Li₃ are active catalysts in the solvent free ring-opening polymerization (ROP) of ε -caprolactone ( ε -CL) and rac -lactide ( rac -LA). High conversions to polycaprolactones were obtained in short periods of time: 1-6 min at 25 °C. Additionally, all four lithium complexes behave as moderately good initiators for the ROP of rac -LA showing high conversions to polylactides at 140 °C in one hour., Competing Interests: The authors declare no conflict of interest.

The behaviour of platinum(II) and palladium(0) complexes coordinated by various hydrosoluble monodentate phosphane ligands has been investigated by 31 P{¹H} NMR spectroscopy in the presence of randomly methylated β-cyclodextrin (RAME-β-CD). This molecular receptor can have no impact on the organometallic complexes, induce the formation of phosphane low-coordinated complexes or form coordination second sphere species. These three behaviours are under thermodynamic control and are governed not only by the affinity of RAME-β-CD for the phosphane but also by the phosphane stereoelectronic properties. When observed, the low-coordinated complexes may be formed either via a preliminary decoordination of the phosphane followed by a complexation of the free ligand by the CD or via the generation of organometallic species complexed by CD which then lead to expulsion of ligands to decrease their internal steric hindrance.

A series of gold(I) complexes of the general composition [Au( n aza)(PPh₃)] ( 1 - 8 ) was prepared and thoroughly characterized (e.g., electrospray ionization (ESI) mass spectrometry and multinuclear nuclear magnetic resonance (NMR) spectroscopy). The N 1-deprotonated anions of 7-azaindole or its derivatives ( n aza) are coordinated to the metal centre through the N 1 atom of their pyrrole ring, as proved by a single crystal X-ray analysis of the complexes [Au( 3I5Br aza)(PPh₃)] ( 7 ) and [Au( 2Me4Cl aza)(PPh₃)]·½H₂O ( 8 '). The in vitrocytotoxicity of the complexes 1 - 8 was studied against both the cisplatin -sensitive and -resistant variants of the A2780 human ovarian carcinoma cell line, as well as against the MRC-5 human normal fibroblast cell line. The complexes 4 , 5 , and 8 , containing deprotonated 3-iodo-7-azaindole, 5-bromo-7-azaindole, and 2-methyl-4-chloro-7-azaindole ( 2Me4Cl aza), respectively, showed significantly higher potency ( IC 50 = 2.8-3.5 µM) than cisplatin ( IC 50 = 20.3 µM) against the A2780 cells and markedly lower effect towards the MRC-5 non-cancerous cells ( IC 50 = 26.0-29.2 µM), as compared with the mentioned A2780 cancer cells. The results of the flow cytometric studies of the A2780 cell cycle perturbations revealed a G₂-cell cycle phase arrest of the cells treated by the representative complexes 1 and 5 , which is indicative of a different mechanism of action from cisplatin (induced S-cell cycle phase arrest). The stability of the representative complex 8 in the water-containing solution as well as its ability to interact with the reduced glutathione, cysteine and bovine serum albumin was also studied using ¹H and 31 P-NMR spectroscopy (studied in the 50% DMF- d₇ /50% D₂O mixture) and ESI+ mass spectrometry (studied in the 50% DMF/50% H₂O mixture); DMF = dimethylformamide. The obtained results are indicative for the release of the N -donor azaindole-based ligand in the presence of the used biomolecules., Competing Interests: The authors declare no conflict of interests.

β-Galactosidase was immobilized on chitosan-coated magnetic Fe3O4 nanoparticles and was used to produce galactooligosaccharides (GOS) from lactose. Immobilized enzyme was prepared with or without the coupling agent, tris(hydroxymethyl)phosphine (THP). The two immobilized systems and the free enzyme achieved their maximum activity at pH 6.0 with an optimal temperature of 50 °C. The immobilized enzymes showed higher activities at a wider range of temperatures and pH. Furthermore, the immobilized enzyme coupled with THP showed higher thermal stability than that without THP. However, activity retention of batchwise reactions was similar for both immobilized systems. All the three enzyme systems produced GOS compound with similar concentration profiles, with a maximum GOS yield of 50.5% from 36% (w · v(-1)) lactose on a dry weight basis. The chitosan-coated magnetic Fe3O4 nanoparticles can be regenerated using a desorption/re-adsorption process described in this study.

This review deals with olefin carbonylation catalysed by Pd(II)-phosphine complexes in protic solvents. In particular, the results obtained in the carbonylation with ethene are reviewed. After a short description of the basic concepts relevant to this catalysis, the review treats in greater details the influence of the bite angle, skeletal rigidity, electronic and steric bulk properties of the ligand on the formation of the products, which range from high molecular weight perfectly alternating polyketones to methyl propanoate. It is shown that the steric bulk plays a major role in directing the selectivity. Particular emphasis is given to the factors governing the very active and selective catalysis to methyl propanoate, including the mechanism of the catalytic cycles with diphosphine- and monophosphine-catalysts. A brief note on the synthesis of methyl propanoate using a "Lucite" type catalyst in ionic liquids is also illustrated. A chapter is dedicated to the carbonylation of olefins in aqueous reaction media. The nonalternating CO-ethene copolymerization is also treated.