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Reactions of triphosphinoboranes with borane dimethylsulfide provided access to boraphosphacycloalkanes with diverse structures.

A series of novel 2-alkythio-4-chloro-N-[imino-(heteroaryl)methyl]benzenesulfonamide derivatives, 8–24, were synthesized in the reaction of the N-(benzenesulfonyl)cyanamide potassium salts 1–7 with the appropriate mercaptoheterocycles. All the synthesized compounds were evaluated for their anticancer activity in HeLa, HCT-116 and MCF-7 cell lines. The most promising compounds, 11–13, molecular hybrids containing benzenesulfonamide and imidazole moieties, selectively showed a high cytotoxic effect in HeLa cancer cells (IC50: 6–7 μM) and exhibited about three times less cytotoxicity against the non-tumor cell line HaCaT cells (IC50: 18–20 μM). It was found that the anti-proliferative effects of 11, 12 and 13 were associated with their ability to induce apoptosis in HeLa cells. The compounds increased the early apoptotic population of cells, elevated the percentage of cells in the sub-G1 phase of the cell cycle and induced apoptosis through caspase activation in HeLa cells. For the most active compounds, susceptibility to undergo first-phase oxidation reactions in human liver microsomes was assessed. The results of the in vitro metabolic stability experiments indicated values of the factor t½ for 11–13 in the range of 9.1–20.3 min and suggested the hypothetical oxidation of these compounds to sulfenic and subsequently sulfinic acids as metabolites.

Herein, we present the synthesis of the first fully characterized monomeric triphosphinoboranes. The simple reaction of boron tribromide with 3 equiv of bulky lithium phosphide

A simple method for the generation of phosphinoborinium cations utilizing synthetically accessible bromophosphinoboranes.

The concept of nonmetallic frustrated cations has been used in the small molecule activation. The in situ generated ambiphilic phosphinoborinium cation activated phenyl isocyanate, diisopropylcarbodiimide, and acetonitrile under very mild conditions without any catalyst, yielding single-, double-, or mixed-activation products. Furthermore, the mechanisms of the reactions of the phosphinoborinium cation with small molecules were elucidated using density functional theory calculations.

Herein, we present a simple synthesis of mixed-valent phosphinophosphoranes bearing three- and five-coordinate phosphorus centers. Compounds with phosphorus-phosphorus bonds were synthesized via a reaction of lithium phosphides RR'PLi with cat

Herein, we present the first example of the activation of small molecules by P–B–P bond systems. The reactivity study involves reactions of two selected diphosphinoboranes, (t-Bu2P)2BPh (1′) and (Cy2P)2BNiPr2 (2), that differ in terms of their structural and electronic properties for the activation of dihydrogen, carbon dioxide, and phenyl isocyanate. Diphosphinoborane 1′ activates H2 under very mild conditions in the absence of a catalyst with the formation of the dimer (t-Bu2PB(Ph)H)2 and t-Bu2PH. Conversely, diphosphinoborane 2 did not react with H2 under the same conditions. The reaction of 1′ with CO2 led to the formation of a compound with an unusual structure, where two phosphinoformate units were coordinated to the PhBOBPh moiety. In addition, 2 reacted with CO2 to insert two CO2 molecules into the P–B bonds of the parent diphosphinoborane. Both diphosphinoboranes activated PhNCO, yielding products resulting from the addition of two and/or three PhNCO molecules and the formation of new P–C, B–O, B–N, and C–N bonds. The products of the activation of small molecules by diphosphinoboranes were characterized with nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, single-crystal X-ray diffraction, and elemental analysis. Additionally, the reaction mechanisms of the activation of small molecules by diphosphinoboranes were elucidated by theoretical methods., The first example of the activation of dihydrogen, carbon dioxide, and phenyl isocyanate by diphosphinoboranes is presented.

We present a comprehensive study on the diphosphanation of iso(thio)cyanates by unsymmetrical diphosphanes. The reactions involving unsymmetrical diphosphanes and phenyl isocyanate or phenyl thioisocyanate gave rise to phosphanyl, phosphoryl, and thiophosphoryl derivatives of amides, imines, and iminoamides. The structures of the diphosphanation products were confirmed through NMR spectroscopy, IR spectroscopy, and single-crystal X-ray diffraction. We showed that unsymmetrical diphosphanes could be used as building blocks to synthesize phosphorus analogues of important classes of organic molecules. The described transformations provided a new methodology for the synthesis of organophosphorus compounds bearing phosphanyl, phosphoryl, or thiophosphoryl functional groups. Moreover, theoretical studies on diphosphanation reactions explained the influence of the steric and electronic properties of the parent diphosphanes on the structures of the diphosphanation products.

In the search for new compounds with antitumor activity, new potential anticancer agents were designed as molecular hybrids containing the structures of a triazine ring and a sulfonamide fragment. Applying the synthesis in solution, a base of new sulfonamide derivatives

Thiophosphinoylation of N-methyl p-substituted benzohydroxamic acids using disulfanes (method A) or diphenylphosphinothioyl chloride (method B) provides only one conformer of the respective O-phosphothioyl derivative (X-ray and NMR analysis). Undergoing the P-transamidoxylation reaction is an evidence of the reversibility of thiophosphinoylation. Only those products containing strong EWG substituents in the aroyl residue or bulky substituents at the phosphorus atom possess E conformation. DFT calculations confirmed the energetic domination of each isomer. The Z-isomers are distorted amides having both high degree of nitrogen pyramidalization (38–55°) and amide twist (12–30°). In solution they exist in a defined conformation that is evidenced by the presence of a sharp signal of N-methyl protons at low temperature. They do not isomerize in solutions. Some of them slowly undergo the N-O bond scission above 100 °C. Both isomers are not as sensitive to neutral hydrolysis as twisted amides can be and are inert toward amines. The rate of alkaline hydrolysis can be correlated with pKa of hydroxamic acid. Because of their outstanding oxyphilicity, these compounds can be defined as nerve agent surrogates and safer alternatives of phosphorus fluorides for serine-active enzyme inhibition studies.

Reaction of copper(I) halides with chiral dithiodianthranilides mdta and bdta afforded polymeric complexes where polynuclear CuX clusters were linked together by ditopic bridging ligands into 1D chains or 2D layer structures. In the case of racemic ligands double stranded chain polymers were formed where the Cu4X4 (X = I or Br) cores are connected by enantiomeric pairs of the ditopic ligands. In contrast, a homochiral mdta ligand created a single stranded hybrid chain involving single mdta enantiomers and solvated Cu5I5 clusters or 2D square (4,4) nets composed of rings comprising four Cu3X3 clusters in nodes and four homochiral ligand molecules in sides with solvent MeCN molecules between the grid layers. The hybrid layer structure obtained from CuCl and the racemic mdta ligand crystallized as a conglomerate that led to its self-resolution into enantiomeric chiral crystals. The solid state CD spectra revealed contribution of two electronic transitions to the diffuse lowest energy absorption band of the complexes. In addition the observed long wavelength Cotton effect sign reflected the helicity of the thiobenzamide chromophore in the ligand unit. At room temperature the solid complexes exhibited weak red phosphorescence near 600–620 nm. Upon cooling down to 10 K all investigated complexes are phosphorescent with average lifetimes of 17–84 μs.

By the reaction of urea or thiourea, acetylacetone and hydrogen halide (HF, HBr or HI), we have obtained seven new 4,6-dimethyl-2-pyrimido(thio)nium salts, which were characterized by single-crystal X-ray diffraction, namely, 4,6-dimethyl-2-oxo-2,3-dihydropyrimidin-1-ium bifluoride, C6H9N2O+·HF2 − or (dmpH)F2H, 4,6-dimethyl-2-oxo-2,3-dihydropyrimidin-1-ium bromide, C6H9N2O+·Br− or (dmpH)Br, 4,6-dimethyl-2-oxo-2,3-dihydropyrimidin-1-ium iodide, C6H9N2O+·I− or (dmpH)I, 4,6-dimethyl-2-oxo-2,3-dihydropyrimidin-1-ium iodide–urea (1/1), C6H9N2O+·I−·CH4N2O or (dmpH)I·ur, 4,6-dimethyl-2-sulfanylidene-2,3-dihydropyrimidin-1-ium bifluoride–thiourea (1/1), C6H9N2S+·HF2 −·CH4N2S or (dmptH)F2H·tu, 4,6-dimethyl-2-sulfanylidene-2,3-dihydropyrimidin-1-ium bromide, C6H9N2S+·Br− or (dmptH)Br, and 4,6-dimethyl-2-sulfanylidene-2,3-dihydropyrimidin-1-ium iodide, C6H9N2S+·I− or (dmptH)I. Three HCl derivatives were described previously in the literature, namely, 4,6-dimethyl-2-oxo-2,3-dihydropyrimidin-1-ium chloride, (dmpH)Cl, 4,6-dimethyl-2-sulfanylidene-2,3-dihydropyrimidin-1-ium chloride monohydrate, (dmptH)Cl·H2O, and 4,6-dimethyl-2-sulfanylidene-2,3-dihydropyrimidin-1-ium chloride–thiourea (1/1), (dmptH)Cl·tu. Structural analysis shows that in 9 out of 10 of these compounds, the ions form one-dimensional chains or ribbons stabilized by hydrogen bonds. Only in one compound are parallel planes present. In all the structures, there are charge-assisted N+—H...X − hydrogen bonds, as well as weaker CAr +—H...X − and π+...X − interactions. The structures can be divided into five types according to their hydrogen-bond patterns. All the compounds undergo thermal decomposition at relatively high temperatures (150–300 °C) without melting. Four oxopyrimidinium salts containing a π+...X −...π+ sandwich-like structural motif exhibit luminescent properties.

Herein, we present the first transformation of borylphosphine into borylphosphinite using nitrous oxide. Borylphosphine reacts with N2O via insertion of a single oxygen atom into the P–B bond and f...

The untypical course of reaction between chalcones and benzenesulfonylaminoguanidines led to the new 3-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-2-(1-phenyl-3-arylprop-2-enylideneamino)guanidine derivatives 8–33. The new compounds were tested in vitro for their impact on the growth of breast cancer cells MCF-7, cervical cancer cells HeLa and colon cancer cells HCT-116 by MTT assay. The results revealed that the activity of derivatives is strongly related to the presence of hydroxy group in the benzene ring at the 3-arylpropylidene fragment. The most cytotoxic compounds 20 and 24 displayed mean IC50 values of 12.8 and 12.7 μM, respectively, against three tested cell lines and were almost 3- and 4-fold more active toward MCF-7 and HCT-116 when compared with non-malignant HaCaT cells. Furthermore, compound 24 induced apoptosis in cancer cells and caused a decrease of mitochondrial membrane potential as well as an increase of cells in sub-G1 phase in contrast to its inactive analog 31. The strongest activity against the most sensitive HCT-116 cell line was found for compound 30 (IC50 = 8 μM), which was 11-fold more effective in the growth inhibition of HCT-116 cells than those of HaCaT cells. Based on this fact, the new derivatives may be promising leading structures for the search for agents for the treatment of colon cancer.

Novel 18- and 23-membered diazomacrocycles were obtained with satisfactory yields by diazocoupling of aromatic diamines with pyrrole in reactions carried under high dilution conditions. X-ray structure of macrocycle bearing five carbon atoms linkage was determined and described. Compounds were characterized as chromogenic heavy metal ions receptors. Selective color and spectral response for lead(II) was found in acetonitrile and its mixture with water. Complexation properties of newly obtained macrocycles with a hydrocarbon chain were compared with the properties of their oligoether analogs. The influence of the introduction of hydrocarbon residue as a part of macrocycle on the lead(II) binding was discussed. Selective and sensitive colorimetric probe for lead(II) in aqueous acetonitrile with detection limit 56.1 μg/L was proposed.

Benzene, toluene, ethylbenzene, and xylenes (BTEX), a class of volatile organic compounds, are harmful pollutants but also very important precursors in organic industrial chemistry. Among different approaches used for the BTEX treatment, the adsorption technology has been recognized as an efficient approach because it allows to recover and reuse both adsorbent and adsorbate. However, the selective adsorption of the components is the key factor for the efficiency of the process. With this view, calixarene-based materials are very promising due to the unique cavity-like structure of the ligand. An unprecedented coordination network based on calixarene of an interesting nanosheet-like morphology was prepared via a solvothermal layer method. This material showed selectivity for non-polar molecules with remarkable uptake of benzene (38.33 mmol/g). In addition, a simple and useful method of BTEX quantification, through 13 C NMR spectroscopy, is reported here for the first time.

By the reaction of benzoyl chloride, potassium isothiocyanate and the appropriate halogenoaniline, i.e. 2/3/4-(bromo/iodo)aniline, we have obtained five new 1-benzoyl-3-(halogenophenyl)thioureas, namely, 1-benzoyl-3-(2-bromophenyl)thiourea and 1-benzoyl-3-(3-bromophenyl)thiourea, C14H11BrN2OS, and 1-benzoyl-3-(2-iodophenyl)thiourea, 1-benzoyl-3-(3-iodophenyl)thiourea and 1-benzoyl-3-(4-iodophenyl)thiourea, C14H11IN2OS. Structural and conformational features of the compounds have been analyzed using X-ray diffraction and theoretical calculations. The novel compounds were characterized by solid-state IR and 1H/13C NMR spectroscopy. The conformations and intermolecular interactions, such as hydrogen bonds, π–π and S(6)...π stacking, and X...O (X = I or Br), I...S and I...π, have been examined and rationalized, together with four analogous compounds described previously in the literature. The set of nine compounds was chosen to examine how a change of the halogen atom and its position on the phenyl ring affects the molecular and crystal structures.

The preparation and characterization of products of the chemical and photochemical rearrangements of a 19-membered o,o'-azoxybenzocrown are presented. In photochemical rearrangement, besides the expected product i. e. 19-membered o-hydroxy-o,o'-azobenzocrown (19-o-OH) obtained under defined conditions with 75 % yield, also other macrocyclic products were isolated and identified, namely: 19-membered p-hydroxy-o,o'-azobenzocrown (19-p-OH), 21-membered o'-hydroxy-o,p'-azobenzocrown (21-o'-OH) and 19-membered macrocycle containing a 5-membered ring bearing an aldehyde group (19-al). The structures of two atypical products of the photochemical rearrangement - 21-o'-OH and 19-al - were determined in the solid state by X-ray analysis and in solution using NMR spectroscopy. Tautomeric equilibrium of the formed hydroxyazobenzocrowns and its change depending on acidity/basicity of the environment and alkali and alkaline earth metal cations complexation were studied using UV-Vis spectrophotometry, spectrofluorimetry and 1 H NMR spectroscopy.

We present a series of amino- and aryl(diphosphino)boranes R2PB(R′′)PR′2, where R2P, R′2P = tBu2P, tBuPhP, Ph2P, Cy2P, and R′′ = iPr2N, Ph, which were obtained via the metathesis reaction of iPr2NBBr2 or PhBBr2 with selected lithium phosphides. The structures of isolated diphosphinoboranes were characterized in the solid state and in solution by means of X-ray diffraction and NMR spectroscopy, respectively. The utility of these P–B–P species as ligands for transition metal complexes was tested in the reaction with [(COD)PtMe2]. Moreover, we carried out DFT calculations to elucidate bonding interactions and philicity of the reactive centers as well as to analyze conformations of the studied species. Electronic and steric properties of substituents on P and B atoms were found to have a strong influence on the structures of the obtained compounds. Three main types of diphosphinoboranes were distinguished, based on the strength of P–B π-interaction within the molecule: (i) application of strong electron-donating substituents on P-atoms and electron-accepting phenyl groups on B atoms led to the structure with one double PB and one single P–B bond and diverse planar and pyramidal geometry of phosphanyl groups; (ii) reduction of the donor ability of phosphanyl groups gave diphosphanylboranes with delocalized P–B–P π-interactions; (iii) introduction of amino groups with strong donor abilities on B atoms canceled P–B π-interactions and allowed compounds with two very long P–B bonds and two pyramidal phosphanyl groups to be obtained.

Cyclic 8-, 9-, 10-, and 12-membered bis(anisylphosphonothioyl)disulfanes were synthesized. Next, structurally related 7 to 9-membered cis and trans sulfanes were isolated as a result of sulfur atom extrusion from the parent cyclic disulfanes. The results of the desulfurization of the disulfanes using triphenylphosphine were compared to the results obtained for desulfurization of the respective bis(anisylphosphodithioates) with the aid of 2-chloro-N-methylpyridinium iodide. Cyclic disulfanes predominantly provide trans-sulfanes, and the expansion of their ring sizes causes the cis/trans isomer ratio of the cyclic sulfanes to increase. Moreover, bis(anisylphosphodithioates) mainly afford cis-sulfanes, and the cis/trans isomer ratio is greater than 3 : 1. Mechanistic and stereochemical aspects of cyclic disulfane desulfurization have been presented to elucidate the above findings. Although it was suggested by calculations that cis-sulfanes are more thermodynamically stable than their respective trans isomers, the cyclisation is a kinetically controlled reaction, which results in predominance of trans-sulfanes in the case of trans-disulfane desulfurization. Disulfanes exhibit thermal and solvolytic stability (except in wet DMSO). A characteristic persistent deep-blue coloration of methanolic ammonia solutions is an unusual feature of cyclic disulfanes. The mechanism of their ammonolysis has been studied and has been compared to that of the respective reaction performed on acyclic disulfanes. Ammonia solution of an acyclic disulfane is colourless and contains phosphosulfenamide and dithiophosphate, while the respective mixture of cyclic disulfane consists of thiophosphonoamide-phosphonodithioate, O-methyl thiophosphonate–phosphonodithioate and deep blue sulfur-ammonia species. Detailed X-ray structural analysis was performed for all trans-disulfanes and cis- and trans-sulfanes. They were compared to each other and to their acyclic or cyclic known analogs that comprise common subunits. 8-, 9-, 10-, and 12-membered disulfanes exist as trans isomers exclusively both in the solid state and in solution. They are significantly more stable than their hypothetical cis isomers, as shown by DFT calculations. The PSSP torsion angles of cyclic disulfanes lie in the range of 94° to 125° and increase with the size of the ring. These values are greater than the typical torsion angles found for the respective non-cyclic disulfanes. The greater stability of the cis-sulfanes was confirmed by calculations and can be ascribed mainly to the characteristic anisyl–anisyl stacking. Special attention was paid to the importance and the role of weak hydrogen bonds (CH…O/S) in conformational stabilization and intermolecular interactions. The conformations of cyclic disulfanes and cyclic sulfanes found in the crystalline state were also preserved in solution (variable temperature NMR). A Karplus relationship has been established between the dihedral angles and vicinal H–P coupling constants for all disulfanes and sulfanes. The effects of solvent on the 1H NMR chemical shifts (ASIS) were determined and were associated with the dipole moments of the sulfanes.

Optically active ditopic halogen bond donors bearing two 4-iodotetrafluorophenyl groups were obtained by reaction of chiral diols with iodopentafluorobenzene. Co-crystallization of these donors with anti-4,4′-azopyridine afforded binary complexes containing infinite chains of the alternating component molecules connected by halogen bonds. The solid state CD measurements confirmed that complexation induces optical activity of the azo chromophore due to the twisting of the aryl-NN system or external chiral perturbation exerted by host molecules.

Herein, we present the first transformation of borylphosphine into borylphosphinite using nitrous oxide. Borylphosphine reacts with N2O via insertion of a single oxygen atom into the P–B bond and formation of a P–O–B bond system. Borylphosphine and borylphosphinite capture SO2 and activate it in an irreversible and reversible manner, respectively., The first example of N2O and SO2 activation by phosphinoboranes is presented.

The reactivities of phosphanylphosphinidene complexes [(DippN)2W(Cl)(η2-P–PtBu2)]− (1), [(pTol3P)2Pt(η2-P=PtBu2)] (2), and [(dppe)Pt(η2-P=PtBu2)] (3) toward dihaloalkanes and methyl iodide were investigated. The reactions of the anionic tungsten complex (1) with stochiometric Br(CH2)nBr (n = 3, 4, 6) led to the formation of neutral complexes with a tBu2PP(CH2)3Br ligand or neutral dinuclear complexes with unusual tetradentate tBu2PP(CH2)nPPtBu2 ligands (n = 4, 6). The methylation of platinum complexes 2 and 3 with MeI yielded neutral or cationic complexes bearing side-on coordinated tBu2P–P-Me moieties. The reaction of 2 with I(CH2)2I gave a platinum complex with a tBu2P—P—I ligand. When the same dihaloalkane was reacted with 3, the P—P bond in the phosphanylphosphinidene ligand was cleaved to yield tBu2PI, phosphorus polymers, [(dppe)PtI2] and C2H4. Furthermore, the reaction of 3 with Br(CH2)2Br yielded dinuclear complex bearing a tetraphosphorus tBu2PPPPtBu2 ligand in the coordination sphere of the platinum. The molecular structures of the isolated products were established in the solid state and in solution by single-crystal X-ray diffraction and NMR spectroscopy. DFT studies indicated that the polyphosphorus ligands in the obtained complexes possess structures similar to free phosphenium cations tBu2P+=P−R (R = Me, I) or (tBu2P+=P)2., The phosphanylphosphinidene complexes of tungsten and platinum as building blocks for syntheses of polydentate phosphorus ligands.

A bstract A series of new N'-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-1-(5-phenyl-1H-pyrazol-1-yl)amidine derivatives have been synthesized and evaluated in vitro by MTT assays for their antiproliferative activity against cell lines of colon cancer HCT-116, cervical cancer HeLa and breast cancer MCF-7. The studied compounds display selective activity mainly against HCT-116 and HeLa cells. Thus, five compounds show selective cytotoxic effect against HCT-116 (IC50 = 3–10 μM) and HeLa (IC50 = 7 μM). Importantly, the noticed values of IC50 for four compounds are almost 4-fold lower for HeLa than non-malignant HaCaT cells. More-in-depth biological research revealed that the treatment of HCT-116 and HeLa with active compound resulted in increased numbers of cells in sub-G1 phase in a time dependent manner, while non-active derivative does not influence cell cycle. Metabolic stability assays using liver microsomes and NADPH provide important information on compounds susceptibility to phase 1 biotransformation reactions.

One mononuclear and two binuclear HgII complexes have been synthesized and characterized by X-ray diffraction, ATR IR and Hirshfeld surface analysis. Single-crystal X-ray diffraction showed that binuclear compounds are centrosymmetric and isostructural. All complexes form bifurcated intermolecular N–H⋯O hydrogen bonds that contribute to a formation of the centrosymmetric dimers. In binuclear complexes, sulfur atoms of thiourea ligands take the bridging role. These are the first examples of such compounds with mercury. In binuclear complexes of group 12 elements, halogens are usually the bridging atoms. The geometries of binuclear complexes are highly distorted with alarmingly low value of τ 4 ′ parameter suggesting presence of additional donor that turned out to be phenyl ring (Hg⋯π interaction). The crystal structures are stabilized by additional noncovalent interactions, including halogen bonding which leads to the formation of chains. The differences and similarities of these complexes indicate that halogen ions have a great impact on the structures. Presented complexes comprise unique interactions between mercury-bonded halogen atoms and neighboring oxygen atoms of carbonyl groups (Hg–(Cl, Br, I)⋯O C contacts).

A copper-tartrate, [Cu2(Tart)2(H2O)2]·4H2O, was synthesized at room temperature in aqueous media using copper chloride and d -tartaric acid. The compound crystallizes in the monoclinic system P21 space group and was characterized by infrared spectroscopy, thermogravimetry, X-ray powder diffraction and the results are in good agreement with the single crystal structure. Catalytic properties for allylation of aldehydes were investigated at different solvents, and the best conditions obtained were using a mixture of CH2Cl2:H2O. The copper-tartrate obtained showed good performance as catalyst for different substrates and yields were between 62% and 95%.

Two new crystal structures of eight- and ten-membered cyclic bis­anisyl­phosphono­thioyl disulfanes have been determined and these are compared to the structures of their ferrocenyl analogues., Two new crystal structures of eight- and ten-membered cyclic bis­anisyl­phosphono­thioyl disulfanes, namely 2,5-bis­(4-meth­oxy­phen­yl)-1,6,3,4,2λ5,5λ5-dioxadi­thiadi­phospho­cane-2,5-di­thione, C16H18O4P2S4, and 2,5-bis­(4-meth­oxy­phen­yl)-1,6,3,4,2λ5,5λ5-dioxadi­thia­diphosphecane-2,5-di­thione, C18H22O4P2S4, have been determined and compared to structures of the ferrocenyl analogues. The eight-membered rings have similar conformations (TBC) but the ten-membered macrocycles are differently puckered. Structural parameters of the relevant SPSSPS motif have been analysed and are discussed in detail. Compound 1 was refined as an inversion twin and 2 was refined as a two-component rotational twin.

The synthesis of a potential immunosuppressant, i.e. dimethyl ester of N-mycophenoyl malonic acid was optimized in the reaction of mycophenolic acid (MPA) with amino malonic dimethyl ester in the presence of propanephosphonic anhydride (T3P) as a coupling reagent. The structural properties of the obtained MPA derivative were investigated by NMR, MS and single crystal X-ray diffraction methods. Theoretical considerations of conformational flexibility based on DFT calculations are presented.

Aromatic diamides, derivative of 2,6-pyridinedicarboxylic acid and isophthalic acid, bearing 1,3,4-thiadiazole residue were prepared with satisfactory yields in conventional procedures and microwave stimulated reactions. X-ray structure of N,N′-bis(1,3,4-thiadiazol-2-yl)-2,6-pyridinedicarboxamide (2) DMSO solvate (2·DMSO) was described. Selective zinc(II), lanthanum(III), terbium(III) and l -tyrosine recognition was found for N,N′-bis(1,3,4-thiadiazol-2-yl)-2,6-pyridinedicarboxamide in DMSO and its mixture with water. The IDA (Indicator Displacement Assay) system for metal cations sensing was proposed. The binding properties of 2 were compared with newly synthesized N,N′-bis(1,3,4-thiadiazol-2-yl)-1,3-benzenedicarboxamide 1.

Lanthanide-calixarene hybrid materials are of particular interest due to the combination of the interesting properties of the ligand cavity-like structure and the luminescent features of lanthanides. The aim of this study was to synthesize and investigate the photophysical properties of Eu3+, Tb3+ and Gd3+ hybrids based on calix[4]arene-tetracarboxylate. The preparation of two structurally different Tb3+ compounds (calix-TA-SC-Tb and calix-TA-Tb) was dictated by the ligand to metal molar ratio and the synthesis time. Analysis of calix-TA-SC-Tb monocrystals revealed the formation of a mononuclear complex of C2 symmetry containing Tb3+ coordinated by four calixarene ionized groups and formate anion encapsulated within the upper cavity. Syntheses of other hybrids failed in producing high-quality crystals and the structures could not be solved. The solid-state luminescent properties of hybrids were evaluated, and the structure/property relationship was investigated. Based on the emission and excitation spectra, the energy diagrams for calix-TA-Eu, calix-TA-Tb and calix-TA-Gd were proposed.

We have synthesized new luminescent coordination polymers using 4,4׳-sulfonyldibenzoic acid (H2SDA) and several lanthanide ions by open crystallization in DMF. Three different 1-D structures were obtained, as determined by single-crystal X-ray diffraction: [La(η2-NO3)(μ-SDA)(DMF)3]n (1), [Sm(η2-NO3)(μ-SDA)(DMF)2·2DMF]n (3), [Ln(η2-NO3)(μ-SDA)(DMF)2·DMF]n (Ln = Eu (4), Dy (5), Ho (6), Er (7), Tm (8) and Lu (9)). A 2-D structure, [Er2(η2-SDA)3(DMF)(H2O)3·2DMF]n (10), was also obtained. The measured photophysical properties of these compounds seem to be interesting for applications (high lifetime, narrow line width and high degree of color purity). In addition, emission spectra, spontaneous emission coefficients (Arad and Anrad), and intensity parameters (Ω2 and Ω4), from spectroscopic data of Eu3+, were used to evaluate crystal stabilities. Differences in the spectra acquired before and after DMF removal clearly reflected the changes taking place in the ion environment.

It is widely believed that the hydrophobic effect governs the binding of guest molecules to cyclodextrins (CDs). However, it is also known that high hydrophobicity of guest molecules does not always translate to the formation of stable inclusion complexes with CDs. Indeed, a plethora of other factors can play a role in the efficiency of guest–CD interactions, rendering structure-based prediction of the complexation efficiency with CDs a non trivial task. In this combined experimental and computational study, we examine the major structural factors governing complexation efficiency of polycyclic aromatic drug-like compounds with natural CDs, using as an example iminostilbene and its N-substituted derivatives. We find that purely hydrophobic IS derivatives show negligible complexation efficiency with CDs and only IS with hydrophilic substituents form stable inclusion complexes in water. We show that the balance between the guest solubility and its affinity to CDs is critical for the effective formation of inclusion complexes. Finally, our results demonstrate that guest–host hydrogen bonds facilitate the formation of crystalline inclusion complexes with CDs.

The monomeric diaminophosphinoboranes readily react with CO