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Novel copper(II) coordination polymers (CPs) [Cu(μ-4-NO2pz)2]n and [Cu(μ-4-NO2pz)2·DMF H2O]n (4-NO2pz− = 4-nitropyrazolate; DMF = N,N′-dimethylformamide) were synthesized and characterized in the solid state and their thermal behaviour and structural features were investigated. Together with the known CPs [Cu(μ-pz)(μ-OH)]n, [Cu(μ-pz)2(H2O)]n and [Cu(μ-4-Xpz)2(DMF)]n [pz− = pyrazolate; 4-Xpz− = 4-X-pyrazolate, with X = H, Cl, Br, I], they were isolated in the form of very small particles whose dimensions range within 20–300 nm and, as such, they were investigated as potential antibacterial agents. Their antibacterial activity was assessed against two Gram-negative bacteria, namely Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), and the Gram-positive bacterium Staphylococcus aureus (S. aureus), by monitoring the bacterial growth curve and the antibacterial rate as a function of time. The bactericidal mechanism seems to be related to the ROS production, directly activated by the contact of the CP tiny particles with the bacterial membrane, without a significant release of Cu(II) ions. [ABSTRACT FROM AUTHOR]

Hydrazones and their metal derivatives are very important compounds in medicinal chemistry due to their reported variety of biological activities, such as antibacterial, antifungal and anticancer action. Five hydrazone-pyrazolone ligands H2Ln (n = 1–5) were prepared and fully characterized and their tautomerism was investigated in the solid state and solution. Five zinc(II) complexes 1–5 of composition [Zn(HLn)2] (n = 1 and 2), [Zn(HLn)2(H2O)2] (n = 3 and 5) and [Zn(HL4)2]n were synthesized and characterized by elemental analysis, IR, 1H, 19F, 13C, and 15N NMR spectroscopy, and ESI mass spectrometry. In addition, the structures of two ligands and three complexes were determined by single-crystal X-ray diffraction. The ligands H2L2 and H2L4 exist both in the NH,NH tautomeric form. Complexes 1 and 2 are mononuclear compounds, while complex 4 is a one-dimensional coordination compound. Density functional theory (DFT) calculations were carried out on proligands, their anions and all zinc complexes, confirming the experimental results, supporting IR and NMR assignments and giving proofs of the mononuclear diaqua structure of complexes 3 and 5. The antibacterial activity of the free ligands and the Zn(II) complexes was established against Escherichia coli and Staphylococcus aureus, and a strong efficiency has been found for Zn(II) complexes, particularly for the polynuclear 4 and the mononuclear diaqua complex 5, the latter containing a ligand with aliphatic and fluorinated substituents able to compromise the permeability of and disrupt the bacterial cell membrane. [ABSTRACT FROM AUTHOR]

Here, the interaction between N,N-dimethyl-selenobenzoamide PhC(＝Se)NMe2 (1) and various Lewis acids of different strengths, namely IC6F13(I), B(C6F5)3 (B) and Me+, has been analysed by a combined experimental and theoretical approach. In all cases, an increase of the C–NMe2 rotational barrier has been evidenced and quantified by 1H-variable temperature-exchange NMR spectroscopy (VT-EXSY) in the cases of 1-I and 1-B. For B(C6F5)3, the structure of the adduct has been elucidated by single crystal X-ray diffraction, allowing the lengthening of the Se–C bond (186 pm) and the consequent double characteristic of the C–NMe2 bond (131 pm) to be measured. Computational studies (mainly natural bond orbitals and natural orbital for chemical valence analyses) gave precious insight into the effect of various Lewis acids on the electronic structure of 1. The advantages and the limitations of this new method to characterize chemical interactions are discussed. [ABSTRACT FROM AUTHOR]

A series of 4‐aryl‐2‐imino‐1,3‐dithiolanes was synthesized by means of a straightforward strategy starting from readily available precursors: reactions of dithiocarbamates and arylsulfonium salts, at room temperature in water/CH2Cl2 as biphasic medium, afforded the five‐membered cyclic products in good yields. The reaction mechanism was investigated by DFT calculations. [ABSTRACT FROM AUTHOR]

A critical comparison of the direct stoichiometric reactions of homoleptic halides of metals belonging to groups 5, 6 and 15, in an oxidation state of +V or +VI, with N- or O-organic compounds. [Display omitted] • Homoleptic halides of high-valent transition metals. • Structure, preparation, properties. • Halides of metals belonging to groups 5, 6 and 15. • High oxidation state. • Reactivity with O- and N-donors. • Parallel chemistry of the pentahalides of group 15. Homoleptic halides of high-valent transition metals are acidic species possessing a strong affinity to N- and O-donors. The formation of coordination adducts with related organic ligands may be a prelude to subsequent activation reactions proceeding according to a variety of unconventional reactivity patterns. General aspects regarding the structure, the preparation, the properties and the salient reactivity of halides of elements belonging to groups 5, 6, 15 and (to a lesser extent) 16 of the periodic table, in an oxidation state of +V or + VI (when available), will be provided. Then, focusing on the most easily available metal halides (MX 5 , M = Nb or Ta, X = F or Cl; MoCl 5 and WCl 6), the direct reactions with different categories of oxygen (carbonyl compounds, ethers, alcohols) and nitrogen (amines, imines, nitriles) organics will be discussed using a comparative approach, including the parallel chemistry of the pentahalides of group 15. [ABSTRACT FROM AUTHOR]

This paper aims to make a socioeconomic analysis over rural settlements in the extreme south of Bahia and in Pontal do Paranapanema in São Paulo state. Its emphasis is on cassava agrobiodiversity. Semi-structured interviews were conducted with fifteen farmers in ten settlements in Bahia and eleven farmers in seven settlements in São Paulo. Those regions socioeconomic levels are among the lowest in their states, with major vulnerability in Bahia. About 60% of farmers's children live in the settlement, two thirds of them work on agricultural activities. Composed mainly by elderly population, settlements in Bahia represent most of cassava diversity, whose production provides to the artisanal flour production flour. The cultural dynamics over the flour production activities in the settlements constitute a key element in the region's agrobiodiversity maintenance. The Pontal's cassava production on the other hand, answers to the demand of industrial starch outside the settlements, which causes the growing of few varieties that answer to the industrial standards. The Bahia settlements' agroecological perspective has been fundamental to its agrobiodiversity enhancement while the industrial agriculture perspective endorsed in São Paulo's region weakens the agricultural diversity as well as its sociocultural structures associated with the agrobiodiversity maintenance. [ABSTRACT FROM AUTHOR]

Five‐ and six‐coordinated zinc(II) complexes, [Zn(QR)2(H2O)] (1–2) and [Zn(QR)2(L)] (3–8) {HQR = 4‐R(C=O)‐5‐pyrazolones in general, in detail HQC17, R = –(CH2)16CH3, HQCy, R = –C6H11; L = bipy, tmeda or en} have been synthesized and characterized by IR, 1H and 13C NMR, UV/Visible spectroscopy, elemental analysis, TGA and ESI mass spectrometry. The square pyramidal complex [Zn(QC17)2(H2O)] (1) has been structurally characterized, together with a trans octahedral [Zn(QCy)2(EtOH)2] (2b) species obtained by recrystallization of [Zn(QCy)2(H2O)] (2) from ethanol. Additionally, in both complexes [Zn(QCy)2(bipy)] (4) and [Zn(QC17)2(tmeda)] (5) structurally characterized by single crystal X ray diffraction, the same amount of Δ and Λ enantiomers are present, with the only difference related to the mutual disposition of the different type of the QR coordinated oxygen atoms. The cytotoxicity of the complexes [Zn(QCy)2(H2O)] (2), [Zn(QCy)2(bipy)] (4) and [Zn(QCy)2(en)] (8) has been evaluated in vitro against MCF‐7 human breast cancer cell line in a biohybrid membrane system. Results revealed that zinc complexes possess antiproliferative activity inducing apoptosis by activation of caspase‐3 and p‐JNK. [ABSTRACT FROM AUTHOR]

Transition metal carbamates constitute a class of compounds with unique properties, however their catalytic potential has been sparingly explored so far. The easily available silver N,N-dimethylcarbamate, Ag(O2CNMe2), worked as a catalyst in the carboxylation reaction of terminal alkynes with CO2 at atmospheric pressure. Different reaction parameters (solvent, base, temperature, time and the amount of catalyst) were investigated in order to establish the optimal conditions. [ABSTRACT FROM AUTHOR]

Triphenylacetic acid underwent unusual decarbonylation when allowed to react with a series of halides of group 4–6 metals in their highest oxidation state, in dichloromethane at ambient temperature. Thus, the reaction of CPh3COOH with MoCl5, in 1 : 1 molar ratio, afforded the trityl salt [CPh3][MoOCl4], 1, in 79% yield, while the 1 : 2 reaction of CPh3COOH with NbF5 afforded [CPh3][NbF6], 2, in 70% yield, NbOF3 being the metal co-product. CPh3COOH reacted with NbCl5, TiF4 and WOCl4 to give mixtures of compounds, however the cation [CPh3]+ was NMR identified in each case. [CPh3][NbCl6], 3, was isolated from NbCl5 and CPh3COCl, prior to being generated from CPh3COOH and PCl5. The reaction of CPh3COOH with TiCl4 was non-selective, and the salt [CPh3][Ti2Cl8(μ-κ2-O2CCPh3)], 4, was obtained in 18% yield. The decarbonylation reactions of CMePh2COCl and CMe2PhCOCl by means of NbCl5 led to the indanes 5a–b, which were isolated in 79–97% yields after hydrolysis of the mixtures and subsequent alumina filtration of the organic phases. The reactions of CH(Ph)2COOH with NbCl5 and WCl6 afforded NbCl4(OOCCHPh2), 6, and CHPh2COCl, respectively, as the prevalent species. CPh2(CH2CH2Br)COOH did not undergo CO release when allowed to interact with WCl6, instead selective intramolecular condensation to C(Ph)2C(=O)OCH2CH2, 7, occurred. MeC≡CCOOH underwent hydrochlorination by WCl6 to give MeC(Cl)=CHCOOH, 8, in 72% yield. All the products were fully characterized by elemental analysis, IR and multinuclear NMR spectroscopy. In addition, the solid state structures of 1, 2, 4, 7, and 8 were elucidated by X-ray diffraction. [ABSTRACT FROM AUTHOR]

The chemistry of diiron complexes has seen a recent renaissance, due to the prominent role played by the element iron in the development of sustainable synthetic processes and the cooperative effects provided by two metal centers working in concert, that is a concept amazingly exploited by Nature. Aminoalkylidyne derivatives of [Fe2Cp2(CO)4] are a convenient scaffold to grow organic fragments; in particular, the facile removal of one CO ligand opens the doors to the unconventional assembly of molecules/ions, affording unusual structural motifs. In particular, vinyliminium complexes result from carbyne–alkyne coupling and offers the opportunity for a great variety of selective derivatization pathways, including addition of nucleophiles, access to substituted ferrocenes, deprotonation and reduction processes, and trapping of small molecules. [ABSTRACT FROM AUTHOR]

Half‐sandwich organometal complexes of RuII, OsII, RhIII and IrIII with β‐diketone‐like ligands have been extensively explored as potential prodrugs in anticancer therapy in recent years. Here a minireview of this class of compounds is provided. A discussion of the basic structural features of the metal complexes is given, together with their in vitro anticancer activity. [ABSTRACT FROM AUTHOR]

A novel flexible ligand with methyl substituted pyrimidine rings and thioether spacers has been synthesised and the corresponding 1 : 1 silver(i) adducts have been obtained by interaction with different silver(i) salts AgX (where X = NO3−, BF4−, ClO4−, CH3SO3−, CF3CO2−, and CF3CF2CF2CO2−). The X-ray single crystal structure determination of two of the new silver(i) adducts (X = NO3− and CF3CO2−) has proved the formation of coordination polymers with Ag(i) ions almost linearly coordinated to two nitrogen atoms of the pyrimidine rings of the multitopic ligand used. The linear coordination mode shown by the new flexible ligand is induced by the presence of the substituents on the pyrimidine rings, regardless of the type of the AgX salt used in the formation of the respective silver(i) derivatives. This observation represents a neat change in comparison to the already reported series of complexes with unsubstituted (and otherwise identical) ligands, in which dinuclear coordination units have been invariably obtained. Computational investigations have been performed with the aim of explaining such an observed change. A computational comparison of a known dinuclear complex and its related polymeric one has been detailed here and has allowed us to highlight the importance of the introduced substituents in changing the ligand interactions internally to their coordination units and among adjacent units in the solid phases. [ABSTRACT FROM AUTHOR]

A series of neutral ruthenium(ii)–arene complexes, [(arene)Ru(QR)Cl] (arene = p-cymene or hexamethylbenzene), containing 4-acyl-5-pyrazolonate (QR) ligands with aromatic substituents in the acyl moiety (a phenyl in QPh and a 1-naphthyl in Qnaph) and related ionic complexes [(arene)Ru(QR)(PTA)][PF6] (PTA = 1,3,5-triaza-7-phosphaadamantane) have been synthesized and characterized by IR, 1H, 13C and 31P NMR spectroscopy, elemental analysis and ESI mass spectrometry. The structures of five of these compounds were also determined by X-ray crystallography. DFT studies have been performed on all complexes and, in the case of two cationic [(arene)Ru(Qnaph)(PTA)][PF6], the existence of two conformers with a different relative orientation of the naphthyl group in the Qnaph ligand has been assessed, showing that they possess similar energies, in agreement with the experimentally observed NMR spectra in solution. The cytotoxicity of the 4-acyl-5-pyrazolonate proligands (HQR) and complexes was evaluated in vitro against human ovarian carcinoma cells (A2780 and A2780cisR) and non-tumorous human embryonic kidney (HEK293) cells. In general, each complex is about equally cytotoxic to all three cell lines and the PTA derivatives with the naphthyl-modified QR ligands are the most active of the series. [ABSTRACT FROM AUTHOR]

The vinyliminium complexes [Fe2{μ-η1:η3-C(CO2Me)C(H)CN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] [R = Me, 1a; R = 4-C6H4OMe, 1b; R = CH2Ph, 1c] react with primary amines (NH2R′; R′= Me, Et, Bun, (CH2)2NH2, CH2Ph) and ammonia to give the corresponding bridging amidine-alkylidene complexes [Fe2{μ-κ1(N):η1(C):η1(C)-C(CO2Me)CH2C{N(Me)(R)}(NR′)}(μ-CO)(CO)(Cp)2] (4a-j) in 70-90% yields. Likewise, the vinyliminium complex [Fe2{μ-η1:η3-C(CO2Me)C(CO2Me)CN(Me)2}(μ-CO)(CO)(Cp)2][SO3CF3] (1d) reacts with NH2R′ (R′= Me, Et) to form the corresponding amidine-alkylidene [Fe2{μ-κ1(N):η1(C):η1(C)-C(CO2Me)CH(CO2Me)C(NMe2)(NR′)}(μ-CO)(CO)(Cp)2] [R′= Me, 8a; R′ = Et, 8b], generating selectively one of the two diastereoisomers associated with the presence of the methylidene unit −CH(COO2Me)- within the bridging ligand. Amination of the vinyliminium complexes 1a-c takes place also with hydrazine, resulting in the formation of [Fe2{μ-κ1(N):η1(C):η1(C)-C(CO2Me)CH2C{N(Me)(R)}(NNH2)}(μ-CO)(CO)(Cp)2] [R = Me, 5a; R = 4-C6H4OMe, 5b; R = CH2Ph, 5c]. Complexes 1b and 1d react with NHMe2, affording the en-(1,1)diamino-alkylidene complexes [Fe2{μ-η1:η3-C(CO2Me)C(R′)C(NMe2)N(Me)(R)}(μ-CO)(CO)(Cp)2] [R = 4-C6H4OMe, R′ = H, 9b; R = Me, R′ = CO2Me, 9d]. The reaction of 1c with piperidine results in formation of the amidine-alkylidene [Fe2{μ-κ1(N):η1(C):η1(C)-C(CO2Me)CH2C{N(Me)(CH2Ph)}(CH2CH2CH2CH═CH2)}(μ-CO)(CO)(Cp)2] (10), which implies piperidine ring-opening. All the products have been purified by alumina chromatography and characterized by analytical and spectroscopic methods; in addition, the molecular structures of 4f, 5b, and 8a have been ascertained by X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

Solid-state, thermally stable tetramethylguanidinium N,N-diethylcarbamate [TMGH][O2CNEt2] was prepared from tetramethylguanidine (TMG), N,N-diethylamine and carbon dioxide (1 atm). The reaction of [TMGH][O2CNEt2] with TiCl4 in toluene afforded [TMGH]2[TiCl6] and TiCl2(O2CNEt2)2. The tetrachlorides of titanium, zirconium and hafnium were effectively converted into the respective mixed dichloride-dicarbamates, MCl2(O2CNEt2)2, by the reaction with either silver diethylcarbamate or the corresponding homoleptic metal N,N-diethylcarbamate, M(O2CNEt2)4. The titanium and hafnium derivatives are trinuclear in the solid state according to X-ray diffraction analysis (M = Ti) and DFT calculations (M = Hf). Instead, ZrCl2(O2CNEt2)4 was obtained as a mixture of two isomers presumably holding dinuclear and trinuclear structures, according to DFT calculations. Difluoride-dicarbamate TiF2(O2CNEt2)4 was prepared in a similar way as the homologous Cl-compound. All the products were characterized by analytical and spectroscopic methods, and by X-ray diffraction in the cases of [TMGH]2[TiCl6] and Ti3Cl6(μ-O2CNEt2)6. The complex Hf4Cl4(O)2(O2CNEt2)6[O(CH2)3CHO]2 was isolated in low yield in crystalline form from a thf solution of HfCl2(O2CNEt2)2, and then X-ray characterized. [ABSTRACT FROM AUTHOR]

A novel bis(pyrazolyl)methane ligand bearing alkyne substituents ( C C t Bu) in the C-4 position of the pyrazole rings has been synthesized together with its Pd(II) dichloride and diacetate complexes. Both the Pd(II) complexes are monomeric species stable in the solid state and in organic solution. The crystal structure of the Pd(II) dichloride complex displays a slightly distorted square-planar geometry and the molecules tend to form dimers associated through π–π stacking interactions between the pyrazolyl rings. The in vitro antitumor activities of the free ligand and of its corresponding Pd(II) complexes toward some human cancer cell lines, such as HeLa, SHSY-5Y and K562, have shown to be lower than cisplatin but with a better response in comparison to their parent free ligand. [ABSTRACT FROM AUTHOR]

A series of ruthenium(II) arene complexes (arene = p -cymene, hexamethylbenzene and benzene) containing dibenzoylmethane ligand (DBMH) of formula [(arene)Ru(DBM)Cl] and their ionic derivatives bearing PTA (1,3,5-triaza-7-phosphaadamantane), of formula [(arene)Ru(DBM)(PTA)]X (X = PF 6 - or SO 3 CF 3 -) have been synthesized and fully characterized. The solid-state structures of five complexes have been determined by single-crystal X-ray diffraction. These ruthenium materials exhibit intense photoluminescence emission at room temperature in the solid state. All complexes effectively bind to calf thymus DNA through intercalative/electrostatic interactions with more affinity for DNA minor groove. Finally, the antitumor activity of both ligand and complexes was evaluated against the U266 and RPMI human multiple myeloma cell lines, and some of them showed a cytotoxic and pro-apoptotic effect toward both cell lines. [ABSTRACT FROM AUTHOR]

A series of ruthenium(II) arene derivatives (arene = cymene (cym), hexamethylbenzene (hmb)) containing avobenzone (1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione, AVBH) and PTA (1,3,5-triaza-7-phosphaadamantane) or PTA-Me (N-methyl-1,3,5-triaza-7-phosphaadamantane cation) have been synthesized and fully characterized. Three types of complexes have been obtained: i.e., neutral [Ru(arene)(AVB)Cl] (1, arene = cym; 2, arene = hmb), monocationic [Ru(arene)(AVB)(PTA)][SO3CF3] (3, arene = cym; 4, arene = hmb), and dicationic [Ru(arene)(AVB)(PTA-Me)][SO3CF3][BF4] (5, arene = cym; 6, arene = hmb). The solid-state structures of 1 and 2 were determined by single-crystal X-ray diffraction. The cytotoxicity of the complexes has been evaluated in vitro against human ovarian carcinoma cells, A2780 and A2780cisR, as well as against nontumorous Human Embryonic Kidney (HEK293) cells. The ionic complexes with hydrophilic PTA and PTA-Me ligands in 3-6 are considerably more active than the neutral complexes 1 and 2. [ABSTRACT FROM AUTHOR]

The diiron µ-aminocarbyne imidoyl complexes [Fe2{µ-CN(Me)(R)}(µ-CO)(CO){C(C≡CR′)=NXyl}Cp2] [R = Xyl, R′ = Ph ( 1a);[1] R = Xyl, R′ = Tol ( 1b);[1] R = Me, R′ = Ph ( 1c); R = Me, R′ = SiMe3 ( 1d); Xyl = 2,6-C6H3Me2, Tol = 4-C6H4Me] have been prepared by the addition of lithium acetylides to precursors containing a terminal isocyanide ligand. The treatment of 1a- c with CF3SO3CH3 afforded the alkynyl(amino)carbene derivatives [Fe2{µ-CN(Me)(R)}(µ-CO)(CO){C(C≡CR′)N(Me)(Xyl)}Cp2][SO3CF3] [R = Me, R′ = Ph ( 2a); R = Xyl, R′ = Ph ( 2b); R = Xyl, R′ = Tol ( 2c)] in high yields. The reactions of 2b, c with CH3OH/NaBF4, NH2R and NaBH4 led to [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO){C(CH=C(Ph)OMe)N(Me)(Xyl)}Cp2][BF4] ( 3), [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO){C(CH=C(Tol)NHR)N(Me)(Xyl)}Cp2][SO3CF3] [R = Et ( 4a); R = Ph ( 4b)], and [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO){C(CH=CHTol)N(Me)(Xyl)}Cp2][SO3CF3] ( 5) in yields of 65-80 %. Complexes 3- 5 were formed by the selective functionalization of the alkynyl group in 2b, c. Complex 2c reacted with NaCH(CN)2/CH2(CN)2 and NaCH(CO2Me)2 to yield [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO){C{N(Me)(Xyl)}CH=C(Tol)C(CN)C(NH2)C(CN)2}Cp2] ( 6) and [Fe2{µ-C(NXyl)C(C(Tol)=C(CO2Me)2)CN(Me)(Xyl)}(µ-CO)2Cp2] ( 7) in yields of 65 and 60 %, respectively. All the products were purified by alumina chromatography, alumina being presumably involved in the formation of 3, and characterized by elemental analysis and IR and NMR spectroscopy. The structures of 2b, 3, 5, and 6 were ascertained by single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

The reactions of WCl6, WCl5 and WOCl4 with a selection of N-substituted ureas (tetramethylurea = tmu; tetraethylurea = teu; 1,3-diphenylurea = dpu; 1,3-dimethylurea = dmu) were performed in chlorinated solvents and then elucidated by means of analytical, spectroscopic and DFT results. The 1 : 2 molar reactions of WCl6 with, respectively, tmu and dpu proceeded with electron interchange and afforded the salts [(O–H–O)-(tmu)2(μ-H)][WCl6], 1a (40% yield), and [(O–H–O)-(dpu)2(μ-H)][WCl6], 1b (65%). Based on X-ray analyses, the cations in 1a,b consist of a O-protonated urea forming H-bond with a second urea unit. [dpu(O-H)][WCl6], 2, was obtained (68% yield) from WCl6/dpu (1 : 1 molar ratio). Dpu itself was identified as the presumably main source of protonation leading to 1b and 2, via N–H bond activation and possible involvement of the solvent (dichloromethane). The complexes WCl5(urea) (urea = dmu, 3a; tmu, 3b; teu, 3c) were isolated in moderate yields by allowing WCl6 to react with the appropriate organic reactant under different experimental conditions. The same complexes 3a–c were obtained in 40–50% yields from the combinations WCl5/urea, and few crystals of WOCl4(teuH), 4, were afforded from WCl5/tmu as a result of adventitious hydrolysis. The reactions of WOCl4 with ureas were not selective in general, although WOCl4(dmu), 5, was isolated in 66% yield. The X-ray structures determined for 3a and 3b constitute the first examples of crystallographic characterization of complexes of tungsten pentachloride with a neutral ligand. [ABSTRACT FROM AUTHOR]

The reactivity of NbCl 5 , NbF 5 and TaCl 5 with a selection of commercial imines was investigated for the first time by using dichloromethane as reaction medium. NbCl 5 reacted with Ph 2 C NH, in 1:2 molar ratio, affording [Ph 2 C NH 2 ][NbCl 5 (N CPh 2 )], 1 , in 55% yield, as result of imine self-protonation. The iminium salt [PhCH NH t Bu][NbCl 6 ], 2 , was isolated in 52% yield from NbCl 5 and PhCH N t Bu (1:1 molar ratio), while a low yield of [ t Bu 2 C NH 2 ][NbCl 6 ], 3 , was identified from NbCl 5 / t Bu 2 C NH. The 1:1 reactions of NbF 5 with Ph 2 C NH and PhCH N t Bu were accompanied by electron interchange and led to the isolation of the salts [Ph 2 C NH 2 ][NbF 6 ], 4 , and [PhCH NH t Bu][NbF 6 ], 5 , respectively, in ca. 50% yields. Few crystals of [Ph 2 C NH 2 ] 2 [Ta 2 Cl 10 O], 6 , were recovered from TaCl 5 /Ph 2 C NH, the anion being probably generated by the action of adventitious water. Compounds 1 – 6 were characterized by elemental analysis, IR and NMR spectroscopy. The structures of 1 , 4 and 6 were ascertained by X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

Internal alkynes (RCCR) react with [Fe2(CS)(CO)3(Cp)2] (1), under UV radiation, to give the complexes [Fe2{μ-η¹:η³-C(R)C(R)CS}(μ-CO)(CO)(Cp)2] [R = Et, 2a; R = Ph, 2b; R = CO2Me, 2c], as a result of CO displacement and alkyne insertion into the metal-CS bond of 1. In addition, the reaction of 1 with EtCCEt affords the metallacycle species [Fe2{μ-η²:η²-C(S)C(Et)C(Et)C(O)}(CO)2(Cp)2] (3) as secondary product. The molecular structures of 2a and 3 have been elucidated by X-ray diffraction studies. Compound 1 reacts with HCCCO2Me, affording the complex [Fe2{μ-η¹:η³-C(H)C(CO2Me)CS}(μ-CO)(CO)(Cp)2] (2d) in modest yield. Complexes 2a,b undergo selective methylation at the sulfur atom, generating the cationic complexes [Fe2{μ-η¹:η³-C(R)C(R)C(SMe)}(CO)(μ-CO)(Cp)2][CF3SO3] [R = Et, 4a; R = Ph, 4b]. The X-ray structure of 4a has also been determined. Finally, 4b undergoes nucleophilic addition of hydride and cyanide (from NaBH4 and NBun4CN, respectively) to form the vinylalkylidene complexes [Fe2{μ-η¹:η³-C(Ph)C(Ph)C(X)(SMe)}(CO)(μ-CO)(Cp)2] [X = H, 5; X = CN, 6]. [ABSTRACT FROM AUTHOR]

The reactions of [WCl6] with a series of ethers have been performed in chlorinated solvent and elucidated by means of analytical, spectroscopic and DFT methods. The addition of tetrahydropyran (thp) or 1,4-dioxane to [WCl6] resulted in the reversible formation of the adducts WCl6... [L = thp (1a), 1,4-dioxane (1b)], detected in solution by NMR spectroscopy. The reaction of [WCl6] with thp in a molar ratio of 1:2 in chloroform at reflux afforded [WOCl4(thp)] (2a), which was isolated in 51% yield. [WOCl4(OMe2)] (2b) and [WOCl3(OMe2)2](3a) were isolated in yields of 53 and 18 %, respectively, from the reaction of [WCl6] with an excess of dimethyl ether. [WOCl3(OEt2)2](3b) was the only identified metal compound produced from the reaction of [WCl6] and OEt2 (1:2 molar ratio). According to NMR studies, the oxide ligand in 2a,b and 3a,b was generated by double C-O bond cleavage involving one equivalent of organic reactant. The 1:1 reaction of [WCl6] with 1,2-diethoxyethane led to [WCl5(κ²-OCH2CH2OEt)] (4) and a minor amount of [WCl4(κ² EtOCH2CH2OEt)] (5). The aryl oxide compound [WCl5(OPh)] (6) was prepared in 62 % yield from the reaction of [WCl6] and anisole by selective Csp3--O bond activation. The prolonged heating of a mixture of [WCl6] and diphenyl ether in 1,2-dichloroethane led to the isolation of the WV complex [WCl5(OPh2)] (7). The molecular structures of 2a and 3a were ascertained by X-ray diffraction. [ABSTRACT FROM AUTHOR]

Reactions of [(η6-cymene)Ru(μ-Cl)Cl]2 with acylpyrazolone ligands HQ′ (HQ′ in general; in detail, HQCH2Cl = 2-chloro-1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)ethanone), HQhex = 1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)heptan-1-one), HQnPe = 1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-3,3-dimethylbutan-1-one)), in the presence of base, gave the corresponding [(η6-cymene)Ru(Q′)Cl] mononuclear complexes. They react with AgX (where X = O3SCF3 or BF4) in dry acetone affording cationic metalla-cycles [(η6-cymene)Ru(Q′)]4(X)4. The complexes were fully characterized by analytical and spectroscopic methods and the solid-state structures of mononuclear and tetranuclear complexes have been determined by single-crystal X-ray diffraction. The hapticity of the acylpyrazolone ligands to the Ru metal centre has also been established by 13C and 15N CPMAS NMR spectroscopy for the complexes where the lack of crystallinity prevented the elucidation of the crystal structure by SCXRD data. [ABSTRACT FROM AUTHOR]

The triphenylammonium salt [NHPh3][WCl6], 1, and the product of the C-C dimerization of triphenylamine, Ph2N(C6H4)2NPh2, 2, were afforded from the reaction between WCl6 and NPh3 in CH2Cl2. Compound 2 was isolated in 43% yield upon hydrolysis of the reaction mixture. The X-ray structure of 1 provides the first crystallographic characterization of the triphenylammonium ion. Combined EPR and DFT studies gave insight into the reaction mechanism, and allowed the identification of WCl5•••[Cl(C6H4)NPh2] as a presumable key intermediate. The reactions of WCl6 with 4-bromotriphenylamine, 4,4′-dimethyltriphenylamine, 9-phenylcarbazole, followed by hydrolytic treatment, led to the dimerization products 3-6, in admixture with variable amounts of the parent amines. N,N,N′,N′-tetrakis(4-bromophenyl)-[1,1′-biphenyl]-4,4′-diamine, 3, was isolated in 60% yield from the reaction of WCl6 with 4,4′-dibromotriphenylamine. [ABSTRACT FROM AUTHOR]

A series of half-sandwich cyclopentadienyl rhodium(iii) and iridium(iii) complexes of the type [Cp*M(curc/bdcurc)Cl] and [Cp*M(curc/bdcurc)(PTA)][SO3CF3], in which Cp* = pentamethylcyclopentadienyl, curcH = curcumin and bdcurcH = bisdemethoxycurcumin as O^O-chelating ligands, and PTA = 1,3,5-triaza-7-phosphaadamantane, is described. The X-ray crystal structures of three of the complexes, i.e. [Cp*Rh(curc)(PTA)][SO3CF3] (5), [Cp*Rh(bdcurc)(PTA)][SO3CF3] (6) and [Cp*Ir(bdcurc)(PTA)][SO3CF3] (8), confirm the expected “piano-stool” geometry. With the exception of 5, the complexes are stable under pseudo-physiological conditions and are moderately cytotoxic to human ovarian carcinoma (A2780 and A2780cisR) cells and also to non-tumorigenic human embryonic kidney (HEK293) cells, but lack the cancer cell selectivity observed for related arene ruthenium(ii) complexes. [ABSTRACT FROM AUTHOR]

The reactions of NbCl 5 with limited amounts (1–2 molar equivalents) of a series of primary, secondary and tertiary amines were investigated in dichloromethane as solvent. The 1:1 reaction of NbCl 5 with NHEt 2 cleanly afforded an equimolar mixture of [NbCl 4 (NEt 2 )] 2 , 1 , and [NH 2 Et 2 ][NbCl 6 ], 2a ; the former product constitutes the first example of structurally characterized Nb(V) chlorido–amido complex. The ammonium salts [NH 3 n Pr][NbCl 6 ], 2b , and [NH 2 i Pr 2 ][NbCl 6 ], 2c , were isolated in 20–30% yields from the 1:1 reactions of NbCl 5 with NH 2 n Pr and NH i Pr 2 , respectively. Cα–H bond activation and Nb(V) to Nb(IV) reduction took place in the reactions of NbCl 5 with NR 3 (R = Bz, Et; Bz = CH 2 Ph). The iminium salt [(PhCH 2 ) 2 N CHPh][NbCl 6 ], 3 , and the ammonium ion [NH(CH 2 Ph) 3 ] + were identified as the prevalent species generated from the 1:1 NbCl 5 /NBz 3 interaction. [NHEt 3 ][NbCl 6 ], 4 , and [NHEt 3 ] 2 [NbCl 6 ], 5 , were isolated in moderate yields from, respectively, the 1:1 and 1:2 molar reactions of NbCl 5 with NEt 3 . The solid state structures of 1 , 2a , 3 , 4 and 5 were ascertained by single crystal X-ray studies. [ABSTRACT FROM AUTHOR]

This review is aimed at updating the current advance of metal complexes bearing acylpyrazolonate ligands. Novel synthetic procedures for acylpyrazolones are reported together with a survey of the ligands biological properties. All the literature since 2005 on metal complexes (main group, transition, lanthanide and actinide metals) containing acylpyrazolones is reported together with a discussion on their main structural features and field of potential applications. [ABSTRACT FROM AUTHOR]

Dinuclear metal complexes have emerged as a promising class of unusually biologically active compounds. Acylpyrazolonato-bridged arene ruthenium complexes of the general formula [(arene) 2 Ru 2 (L′)Cl 2 ] were synthesized in methanol by reacting the arene ruthenium dimer [(arene)RuCl 2 ] 2 with the corresponding acylpyrazolone ligands. The complexes were isolated and fully characterized by spectroscopic methods; the single-crystal X-ray structure analysis of [(cymene) 2 Ru 2 (L 1 )Cl 2 ] is also presented. These ruthenium complexes were found to be cytotoxic towards epithelial cancerous cell lines to a comparable extent to cisplatin but with higher capacity to discriminate between normal and cancer cells. [ABSTRACT FROM AUTHOR]

Educating future scientists and citizens is more effective if students are guided to correctly apply what they learned in school to their daily lives. This experience-based work is focused on the study of a well-known commercial product: cat litter. This material offers different starting points for a critical examination. Questions related to physical properties at the origin of the litter's efficacy, to information on chemical composition provided in the packaging, and to environmental features and possible noxiousness of cat litter were asked to be investigated by secondary school 14--15 year old students, through laboratory experiments based on problem solving approach, analysis of tag claims of different cat litter brands and cooperative learning activities. This multi-disciplinary approach gives the chance to learn effectively chemistry core concepts and to avoid the typical students' lack of attention. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of coinage metal complexes in 1,2-diamines as solvent. • 1:1:2 ionic/mononuclear complexes of silver and copper with triphenylphosphine and 1,2 diamine ligands. • Structure determination of mixed-ligands Cu(I) and Ag(I) complexes shows two crystallographically independent cations which are conformationally different. Crystallization of copper(I) halide : triphenylphosphine mixtures from 1,2-diaminoethane (en = ethylenediamine) has yielded adducts 1:1:2 CuX:PPh 3 :en stoichiometry (X = Cl or I); the chloride and iodide have been characterized by room temperature single crystal X-ray structure determinations; the iodide is a hemisolvate. In both cases, the complex is ionic, the four coordinate CuPN 3 environment comprising both bidentate and unidentate en, i.e [(κ2- N,N' -en)(κ1- N -en)(PPh 3)Cu]+X−. In each case, there are two crystallographically independent cations which are conformationally different. Adduct [(PPh 3)(κ 2- N,N' -en)(κ 1- N -en)Cu]Cl is very unstable and decomposes on air, whereas [(κ 2- N,N' -en)(κ 1- N -en)(PPh 3)Cu]I is sufficiently stable both in the solid state and in solution to be characterized. Adducts of similar stoichiometry are obtained with silver(I) nitrate, and with silver(I) perchlorate with PCy 3 , and 1,2-diaminopropane (pn): the single crystal X-ray structure determinations confirm the ionic/mononuclear formulations [(κ2- N,N' -en)(κ1- N -en)(PPh 3)Ag]NO 3 and [(κ2- N,N' -en)(κ1- N -en)(PCy 3)Ag]ClO 4 that persist also in acetonitrile, as confirmed by conductance values typical of 1:1 electrolytes in this solvent. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dinuclear ionic derivatives of formula [Ag(EPh 3)(en) 2 ] 2 X 2 have been synthesized. • First dinuclear silver derivatives containing both EPh 3 and en ligands. • X-ray studies show en acting both as bridging linker between two Ag centres and as monodentate ligand. • Ancillary ligands EPh 3 strongly influence the Ag-N bond distances and N -Ag-N bond angles. Colourless crystalline adducts obtained by the crystallization of various silver(I) compounds in 1:1 M proportions with EPh 3 (E = P, As, Sb) from 1,2-diaminoethane (ethylenediamine) (en ≡ H 2 N(CH 2) 2 NH 2) have been structurally characterized by room temperature single crystal X-ray studies as 1:1:2 AgX: EPh 3 : en adducts. The array of compounds is isomorphous, triclinic, P 1 ¯ , a ~ 8.5, b ~ 9.2, c ~ 16.9 Å, α ~ 86.6, β ~ 80, γ ~ 65.5°, Z = 1 dimer, being ionic [(Ph 2 E)(N -en)Ag(N -en- N') 2 Ag(N -en)(EPh 3)]2+(X−) 2 , with binuclear centrosymmetric cations containing four-coordinate silver; the nitrogen component of the latter N 3 AgE array is made up of a pair of N from two bridging en groups and, remarkably, one N from unidentate N -en. Compounds have been spectroscopically and structurally characterized for E = P, X = Cl, Br; E = As, X = Cl, Br; E = Sb, X = Cl, Br, NO 3. Bond distances and angles are compared with previous report on literature for AgX: en adducts. [ABSTRACT FROM AUTHOR]

A didactic sequence is proposed for the teaching of chemical equilibrium law. In this approach, we have avoided the kinetic derivation and the thermodynamic justification of the equilibrium constant. The equilibrium constant expression is established empirically by a trial-and-error approach. Additionally, students learn to use the criterion of comparison between equilibrium constant and reaction quotient to predict the direction of reaction. The teaching sequence takes into account the alternative conceptions and learning difficulties highlighted by teaching and research in science education and the need to focus on both the students' learning process and the knowledge on how to learn. [ABSTRACT FROM AUTHOR]

Cl/O interchange took place when WCl6 was allowed to interact with a series of α-aminoacids. The α-ammonium-acylchloride salts [NH2(CH2)3CHC(O)Cl][WOCl5], 1a, and [MeNH2CH2C(O)Cl][WOCl5], 1b, were afforded in ca. 55% yields from the reactions of WCl6 with, respectively, l-proline and sarcosine in CH2Cl2. By using other reaction media (hexane or CHCl3), the α-amino-acylchloride complexes WOCl4[O=C(Cl)CH(CH2)3NH2], 5a, and WOCl4[O=C(Cl)CH(R)NHR′] (R = H, R′ = Me, 5b; R = R′ = H, 5c; R = Me, R′ = H, 5d) were isolated in moderate to good yields from WCl6 and, respectively, l-proline, sarcosine, glycine and l-alanine. The formation of 5a,b is basically the result of HCl release from the parent compounds 1a,b. 5a represents a key intermediate in the course of the reaction leading to (WOCl4)2[μ:κ2(O)-dkp], 2, dkp = (S,S)-octahydrodipyrrolo[1,2-a:1′,2′-d]pyrazine-5,10-dione. 2 was optimally prepared from WCl6/l-proline under high temperature conditions. Hydrolytic treatment of 2 afforded the l-proline-derived 2,5-diketopiperazine (dkp), which was finally isolated with an overall yield of 70%. 1a,b were characterized by X-ray diffractometry, thus providing very rare examples of crystallographically characterized acylchloride derivatives of α-aminoacids. DFT calculations were extensively carried out in order to shed light on structural and mechanistic features. [ABSTRACT FROM AUTHOR]

C–N bond formation involving carbon monoxide and isocyanide ligands is promoted by addition of a series of lithium acetylides to a diiron μ-aminocarbyne complex, i.e. [Fe2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(CNXyl)(Cp)2][SO3CF3] (Xyl = 2,6-C6H3Me2). The reaction proceeds in three steps, i.e. (a) acetylide addition to the CO ligand, (b) acetylide migration to the isocyanide ligand, and (c) C–N coupling. The X-ray molecular structures of 1a and 1b comprise the first example of a κ(C,C′)-N-carbonyl-aminocarbene ligand. [ABSTRACT FROM AUTHOR]

New silver(I) acylpyrazolonato derivatives displaying a mononuclear, polynuclear, or ionic nature, as a function of the ancillary azole ligands used in the synthesis, have been fully characterized by thermal analysis, solution NMR spectroscopy, solid-state IR and NMR spectroscopies, and X-ray diffraction techniques. These derivatives have been embedded in polyethylene (PE) matrix, and the antimicrobial activity of the composite materials has been tested against three bacterial strains ( E. coli, P. aeruginosa, and S. aureus): Most of the composites show antimicrobial action comparable to PE embedded with AgNO3. Tests by contact and release tests for specific migration of silver from PE composites clearly indicate that, at least in the case of the PE, for composites containing polynuclear silver(I) additives, the antimicrobial action is exerted by contact, without release of silver ions. Moreover, PE composites can be re-used several times, displaying the same antimicrobial activity. Membrane permeabilization studies and induced reactive oxygen species (ROS) generation tests confirm the disorganization of bacterial cell membranes. The cytotoxic effect, evaluated in CD34+ cells by MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazoliumbromide) and CFU (colony forming units) assays, indicates that the PE composites do not induce cytotoxicity in human cells. Studies of ecotoxicity, based on the test of Daphnia magna, confirm tolerability of the PE composites by higher organisms and exclude the release of Ag+ ions in sufficient amounts to affect water environment. [ABSTRACT FROM AUTHOR]

The 1:1 M reaction of MoCl 5 with Cl(CH 2 ) 2 OH, in dichloromethane at room temperature, proceeded with chlorine–oxygen interchange and HCl release to give MoOCl 3 in 65% yield. The analogous reactions involving i PrOH, MeOH, L -menthol and H 2 O gave impure MoOCl 3 . MoCl 5 reacted with Me 2 N(CH 2 ) 2 OH in 1:1 M ratio affording the 2-chloroammonium salt [Me 2 NH(CH 2 ) 2 Cl] 2 [Mo 2 O 2 Cl 8 ], 1 . The reaction of MoCl 5 with MeO(CH 2 ) 2 OH afforded a mixture of [Mo(κ 2 O , O ′-O(CH 2 ) 2 OMe) 2 Cl 2 ][Mo 2 O 2 Cl 7 ], 2a , and [Mo(κ 2 O , O ′-O(CH 2 ) 2 OMe) 2 Cl 2 ][MoOCl 4 ], 2b . The products 1 , 2a and 2b were characterized by analytical and spectroscopic techniques, and by X-ray diffractometry. The X-ray structure of 2b shows weak anion–anion interactions, therefore 2b might be alternatively viewed as a Mo 2 O 2 Cl 8 2− salt. [ABSTRACT FROM AUTHOR]

Novel ruthenium half-sandwich complexes containing (N,0)-bound pyrazolone-based β-ketoamine ligands have been prepared, and the solid-state structures of one ligand and five complexes have been determined by singlecrystal X-ray diflraction. Some of the complexes display moderate cytotoxicity toward the human ovarian cancer cell lines A2780 and A2780cisR, the latter line having acquired resistance to dsplatin. [ABSTRACT FROM AUTHOR]

The direct interaction of MoCl5 with a series of carboxylic acids has been elucidated for the first time. The reactions proceed with release of hydrogen chloride and Cl/O interchange between the metal centre and one equivalent of organic substrate: this feature is unique in the context of the chemistry generally shown by transition metal halides with carboxylic acids. The dinuclear complexes [MoOCl2(¹-CX3CO2H)(µ-Cl)]2 (X = H, 1a; X = Cl, 1b) and Mo2O2Cl6(μ-CH3CO2H), 2a, were isolated as the prevalent metal products of the 1 : 2 molar reactions of MoCl5 with CH3COOH and CCl3COOH. Evidence for the formation of Mo2O2Cl6(μ-CCl3CO2H), 2b, was achieved by allowing MoCl5 to react with CCl3COOH in 2 : 3 ratio. Instead the reactions of MoCl5 with a three-fold molar excess of RCOOH afforded the mononuclear complexes MoOCl3(¹-RCO2H)2 (R = CH3, 3a; CCl3, 3b; CHCl2, 3c; CMe3, 3d) in 50-60% yields. The new compounds were characterized by analytical and spectroscopic techniques, moreover the X-ray molecular structures were ascertained for 1a, 1b and 2a; 1a and 1b display single Mo-Mo bond. DFT calculations were carried out in order to shed light into structural aspects. [ABSTRACT FROM AUTHOR]

Thediiron μ-aminocarbyne complexes [Fe2{μ-CN(Me)(R)}(μ-CO)(CO)(CNR′)(Cp)2][SO3CF3] (R = R′ = Xyl, 2a; R = Xyl, R′ = Me, 2b; R = Xyl, R′= But, 2c; R = Xyl, R′ = p-C6H4CF3, 2d; R = Me,R′ = Xyl, 2e; Xyl = 2,6-Me2C6H3), containing an isocyanide ligand, have been obtainedvia CO replacement with the appropriate CNR′ ligand from [Fe2{μ-CN(Me)(R)}(μ-CO)(CO)2(Cp)2][SO3CF3] (R = Xyl, 1a; R = Me, 1b). Compound 2a, upon treatment with NaBH4and heating at reflux temperature in THF solution, is transformedinto the aminocarbene–aldimine [Fe2{μ-η1(C):η1(N)-CN(Me)(Xyl)CHN(Xyl)}(μ-CO)2(Cp)2] (3) in moderate yield. The reactions occurs via formationof the formimidoyl complex [Fe2{μ-CN(Me)(Xyl)}(μ-CO)(CO){C(H)NXyl}(Cp)2] (4a), which has been isolated by reacting 2awith NaBH4at 0 °C. Likewise, the formimidoylcomplex [Fe2{μ-CN(Me)(R)}(μ-CO)(CO){C(H)NR′}(Cp)2] (R = Xyl, R′ = Me, 4b; R = Me, R′= Xyl, 4c) have been obtained from 2b,e, respectively, upon reaction with NaBH4, butthese complexes do not convert into the aminocarbene–aldiminecomplexes analogous to 3. Reactions of 2awith other nucleophiles have been investigated, without obtainingany product similar to 3. Complex 2areactswith NaCN or with LiPPh2, resulting in isocyanide displacementand formation of [Fe2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(CN)(Cp)2] (5) and [Fe2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(PPh2)(Cp)2] (6), respectively. Additionof the organocopper reagent Li2CuCNMe2to 2aaffords the acyl complex [Fe2{μ-CN(Me)(Xyl)}(μ-CO){C(O)Me}(CNXyl)(Cp)2] (7). The thiocarbyne complex [Fe2{μ-CSMe}(μ-CO)(CO)(CNXyl)(Cp)2][SO3CF3] (8), which shows analogies with 2a, reacts with NaBH4, affording the carbene derivative[Fe2μ-{C(SMe)(H)}(μ-CO)(CO)(CNXyl)(Cp)2] (9). The molecular structures of 2aand 3have been determined by X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

The 1:1 molar reaction of WCl6 with tribenzylamine (tba), in dichloromethane, selectively afforded the minimums salt [(PhCH2)2N= CHPh][WCl6], 1, and the ammonium one [tbaH][WCl6], 2, in equimolar amounts. The products were fully characterized by means of spectroscopic methods, analytical methods, and X-ray diffractometry. Density functional theory calculations were carried out with the aim of comprehending the mechanistic aspects. [ABSTRACT FROM AUTHOR]

Abstract: The rare example of protonated aldehyde salt [4-(OH)-3-(OCH3)C6H3CH( O H)][4-(OH)-3-(OCH3)C6H3CHO][TaF6], 1, was isolated in the solid state by the reaction of 4-hydroxy-3-methoxybenzaldehyde (vanillin) with TaF5 in dichloromethane. The product 1 was characterized by X-ray diffraction and IR spectroscopy. The 1:1 reaction of TaF5 with N,N-dimethylaniline in CH2Cl2 cleanly afforded [TaF4(NMe2C6H5)2][TaF6], 2, which was identified by NMR spectroscopy. Attempts of crystallization of 2 resulted in the isolation of the ammonium salt [NHMe2C6H5][TaF6], 3. [Copyright &y& Elsevier]

Six scorpionate complexes of group 10-12 metal elements (CuI, CuII, ZnII, and CdII) containing the anionic hydrotris[3-(2′-thienyl)pyrazol-1-yl]borate (TpTn) ligand were prepared from the reaction of the thallium(I) salt of TpTn with the corresponding metal acceptors in chloroform solution. The air- and heat-stable complexes were characterized by analytical and spectroscopic methods (IR, conductivity, ESI-MS, 1H NMR and 13C NMR solution data) and structurally characterized by single-crystal X-ray studies. The ZnII complexes [Zn(TpTn)X] (X = Cl or Br) contain a tripodal tridentate TpTn ligand, in which the tetrahedral metal environment is completed by a halide; in [Cd(TpTn)2], cadmium is found in an octahedral environment coordinated by two TpTn ligands. In [Cu(TpTn)(PPh3)] ·CHCl3 and [Cu(TpTn)(OC(O)CH3)], TpTn is also coordinated in the tripodal fashion, in which the copper environment is completed by a triphenylphosphine ligand in the former complex and by a symmetrically coordinated bidentate acetate ligand occupying trans-coordinated sites in the latter complex. The reaction of [Zn(TpTn)X] with an excess amount of [Tl(TpTn)] in MeOH yielded [Zn(TpTn)2] and TlX, whereas the reaction of [Zn(TpTn)X] with Na(Tp) gave [Zn(TpTn)2] and [Zn(Tp)2] in a 1:1 molar ratio but not [Zn(TpTn)(Tp)]. By contrast, the reaction of [Tl(TpTn)] with copper(II) sulfate monohydrate in chloroform gave a green powder, which was identified as the [(Hpz3Tn)4CuSO4](∞|∞) coordination polymer containing OSO2 O bridging sulfate groups and four coordinated pyrazole ligands on each metal center, the latter of which arises from the decomposition of the TpTn ligand through B-N bond breaking. Similarly, the interaction between [Tl(TpTn)] and platinum(II) diiodide in chloroform/DMSO proceeded through TpTn decomposition to afford a monomeric trans-[(Hpz3Tn)2PtI2] ·2(CH3)2SO complex, wherein two neutral pyrazole ligands are coordinated to the PtII center. [ABSTRACT FROM AUTHOR]

The 1 : 2 molar reactions of MoCl5, in dichloromethane at room temperature, with tetrahydrofuran (thf ), tetrahydropyran (thp), dioxane and tetrahydrothiophene (tht) afforded, respectively, [Mo(O)Cl3(thf)]2, 1, and MoCl4(L)2 (L = thp, 2; dioxane, 3; tht, 4), in 81-87% yields. The molecular structures of 1, 2 and 4 were ascertained by X-ray diffractometry. DFT and spectroscopic (IR, NMR) studies were carried out in order to shed light on thermodynamic and kinetic aspects of the reaction pathways. [ABSTRACT FROM AUTHOR]

A novel didactic sequence is proposed for the teaching of chemical equilibrium. This teaching sequence takes into account the historical and epistemological evolution of the concept, the alternative conceptions and learning difficulties highlighted by teaching science and research in education, and the need to focus on both the students' learning process and the knowledge to learn. [ABSTRACT FROM AUTHOR]

The 3:1 molar reactions of MF5 (M = Nb, 1a; M = Ta, 1b) with 1,3-dimethoxybenzene in CHCl3 led to the formation of the arenium salts [2,4-(OMe)2C6H5][M2F11] (M = Nb, 3a; M = Ta, 3b) in good yields. The reactions took place with the intermediate formation of (MF5)2[κ2-1,3-(OMe)2C6H4] (M = Nb, 2a; M = Ta, 2b), followed by single-electron oxidation of the arene and production of MF4 (identified by means of EPR spectroscopy as the acetonitrile adduct). Compounds 3a and b were fully characterised both in solution (NMR) and in the solid-state (X-ray, IR and elemental analysis), while 2a and b were identified by NMR spectroscopy in CD2Cl2 solution. The reactions of 1,3-dimethoxybenzene with Ag[NbF6] or Ag[Sb2F11] in CD2Cl2/CHCl3 afforded [2,4-(OMe)2C6H5]+. It was found that 1,3-dimethoxybenzene was inert towards the addition of aqueous H[SbF6] under comparable experimental conditions. [ABSTRACT FROM AUTHOR]

The reactivity of molybdenum pentachloride, 1, with a selection of mono- and diethers was investigated at room temperature in a non-coordinating solvent (dichloromethane). The Mo(iv) complex MoCl4(OMe2)2, 2, was obtained in 75% yield by the reaction of 1 with an excess of Me2O; similarly, MoCl4(κ2-L) [L = EtOCH2CH2OEt, 6a; MeOCH2CH(Me)OMe, 6b] were prepared in good yields by 1 : 1 combination of 1 with the appropriate diether. MoCl5 reacted with OMePh and Et2O affording variable amounts of RCl (R = Me and Et, respectively); MoCl3(OPh)2, 3, was isolated in 60% yield from 1 and OMePh. The reactions of 1 with OMetBu, OtBu(CH=CH2), MeOCH2CH2OCH2Cl and 1,3-dioxane proceeded with non-selective activation of the organic material. The oxido-complexes Mo2O2Cl4(μ-OMe)2(μ-MeOH), 4, and MoOCl3(MeOH)2, 5, were isolated in modest amounts from 1/OMetBu, whereas MoOCl3(κ2-MeOCH2CH2OCH2Cl), 7, was obtained in 32% yield from 1/MeOCH2CH2OCH2Cl. All of the isolated metal products were characterized by spectroscopic and analytical techniques, and by X-ray diffractometry in the cases of 2, 4, 5, 6b and 7. NMR/GC-MS analyses were carried out in order to outline the fragmentation pathways of the organic reactants. [ABSTRACT FROM AUTHOR]

The reactions of M′O(acac)2 [M′ = Ti, V; acac = acetylacetonato anion] with equimolar amounts of MF5 (M = Nb, Ta) in CH2Cl2 afforded Ti(acac)2F2, 1a, and [V(acac)3][MF6] (M = Nb, 4a; M = Ta, 4b), respectively. MOF3 (M = Nb, 2a; M = Ta, 2b) were co-produced from MF5/TiO(acac)2. The intermediate species [TaF4{OTi(acac)2}2][TaF6], 3, was intercepted in the course of the formation of 1a from TiO(acac)2/TaF5. NbCl5 reacted with TiO(acac)2 yielding selectively the previously reported [NbO(acac)Cl2]x, 5, and Ti2(acac)2(μ-Cl)2Cl4, 6. Complex 6 was alternatively obtained from the addition of a two-fold excess of TiCl4 to VO(acac)2. The 1 : 1 reactions of TiX4 (X = F, Cl) with TiO(acac)2 in dichloromethane gave Ti(acac)2X2 (X = F, 1a; X = Cl, 1b) and TiOX2 (X = F, 7a; X = Cl, 7b). The 1 : 1 combination of TiX4 (X = F, Cl) with VO(acac)2 led to 1a,b and VOX2 (X = F, 8a; X = Cl, 8b). The μ-oxido compounds (C6F5)3B–O–M′(acac)2 (M′ = Ti, V) underwent fragmentation by [PF6]− in chlorinated solvent, yielding POF3, 9, and [B(C6F5)3F]−, 10, according to NMR studies; 1a and V(acac)3+, respectively, were detected as the metal-containing species. Electrochemical studies were carried out aiming at the full characterization of the products and the observation of possible degradation pathways. [ABSTRACT FROM AUTHOR]

The vinyliminium complexes [Fe2{μ-η1:η3-C(R)C(R)CN(Me)2}(μ-CO)(CO)(Cp)2][SO3CF3] (R = Me, 3a; R = CO2Me, 3b; R = Ph, 3c) were treated with S8 in the presence of tBuLi, undergoing fragmentation and affording the corresponding six-membered metallacyclic complexes [Fe(Cp)(CO){SC(R)=C(R)C(NMe2)S}] ( 5a- c). Complexes 5a- c result from cleavage of the diiron precursor and addition of S to the vinyliminium ligand to generate a dithiochelating ligand. Analogous reactions of the vinyliminium complexes [Fe2{μ-η1:η3-C(R)C(R)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (R = Me, 3d; R = CO2Me, 3e), which contain a Xyl group (Xyl = 2,6-Me2C6H3) in place of a methyl, displayed a different outcome. Complex 3d afforded the diiron complex [Fe2{μ-η1:η3-C(Me)=C(CS2)C=N(Me)(Xyl)}(μ-CO)(CO)(Cp)2] ( 10), whereas 3e led to the formation of the five-membered metallacycle [Fe(Cp)(CO){C{N(Me)(Xyl)}C(CO2Me)C(CO2Me)S}] ( 11) together with the diiron complex [Fe2{μ-η1:η3-C(CO2Me)=C(S)C=N(Me)(Xyl)}(μ-CO)(CO)(Cp)2] ( 12). The formation of 10 and 12 implies C-H and C-C cleavage, respectively, and C-S bond formation without rupture of the diiron framework. The vinyliminium complexes 3a- d and also [Fe2{μ-η1:η3-C(Et)C(Et)CN(Me)(CH2Ph)}(μ-CO)(CO)(Cp)2][SO3CF3] ( 3f) reacted with gray selenium in the presence of tBuLi to afford the five-membered metallacycles [Fe(Cp)(CO){C{N(Me)R}C(R′)C(R′)Se}] (R = R′ = Me, 13a; R = Me, R′ = CO2Me, 13b; R = Me, R′ = Ph, 13c; R = Xyl, R′ = Me, 13d; R = CH2Ph, R′ = Et, 13f) in which one Se atom has been incorporated into the chelating ligand. The X-ray molecular structures of 5a and 13a have been determined. [ABSTRACT FROM AUTHOR]

The 1:3 reactions of the alkoxy arenes 1,4-(MeO)2C6H4 and 1,4-F2-2,5-(MeO)2C6H2 with TaF5 in chloroform at 40-50 °C resulted in formation in about 35 % yield of the long-lived radical cation salts [1,4-(MeO)2C6H4][Ta2F11] ( 2 a) and [1,4-F2-2,5-(MeO)2C6H2][Ta2F11] ( 2 b), respectively. The non-alkoxy-substituted [arene][M2X11] [M=Ta, X=F: arene=C6H5Me ( 2 c), 1,4-C6H4Me2 ( 2 d), C6H5F ( 2 e), C6H5NO2 ( 2 f); M=Nb, X=F: arene=C6H5Me ( 4 a), 1,4-C6H4Me2 ( 4 b), C6H5F ( 4 c), C6H5NO2 ( 4 d); M=Ta, X=Cl: arene=1,4-C6H4Me2 ( 5)] were obtained from the 3:1 reactions of MX5 with the appropriate arene in chloroform at temperatures in the range 40-90 °C. Compounds 2- 5 were detected by EPR spectroscopy (in CHCl3) at room temperature, and their gas-phase structures were optimized by DFT calculations. Formation of the MIV species [MX4(NCMe)2] [M=Ta, X=F ( 3 a); M=Nb, X=F ( 3 b); M=Ta, X=Cl ( 3 c)] was ascertained by EPR spectroscopy on solutions obtained by treatment of the reaction mixtures with acetonitrile. Non-selective reactions occurred upon combination of 1,4-F2-2,5-(MeO)2C6H2 with AgNbF6 (in CH2Cl2) and 1,4-(MeO)2C6H4 with SbF5. [ABSTRACT FROM AUTHOR]