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The new diiron(I) complexes [Fe2Cp2(μ‐CO){μ‐k3C,kN‐C(R1)C(R2)C(CN)NMe(R)}], 3 a–o (R=alkyl or 4‐C6H4OMe; R1=alkyl, aryl, ferrocenyl (Fc), thiophenyl, CO2Me or SiMe3; R2=H, Me or CO2Me) were synthesized in moderate to high yields from the thermal decarbonylation of the bis‐carbonyl precursors 2 a–o, and were structurally characterized by IR and NMR spectroscopy, and single crystal X‐ray diffraction in four cases. Electrochemical behavior of one complex was also investigated. Complexes 3 a–o comprise a highly functionalized, multisite amino‐(cyano)allylidene ligand, including metal coordination of a tertiary amine group. Selected complexes displayed negligible to moderate catalytic activity in CO2/propylene oxide coupling, working under ambient conditions. Additionally, they were investigated as catalysts for the conversion of benzaldehyde to the corresponding borate ester 6 a, using pinacolborane (HBpin) as the borylating agent. Most complexes achieved good conversions at room temperature with 1 % catalyst loading, and data highlight the significant influence of the multisite ligand substituents on the catalytic performance. Notably, complex 3 m (featuring R=4‐methoxyphenyl, R1=Fc, R2=H) displayed the highest activity and effectively catalyzed the hydroboration of various aldehydes and ketones. A plausible mechanistic cycle involves metal coordination of the carbonyl substrate, its activation being possibly facilitated by intramolecular interactions. [ABSTRACT FROM AUTHOR]

Tris(pyrazolyl)methane (tpm), 2,2,2-tris(pyrazolyl)ethanol (tpmOH) and its esterification derivatives with ibuprofen and flurbiprofen (tpmIBU and tpmFLU) were used as ligands to obtain complexes of the type [Fe(tpmX)2]Cl2 (1–4). The tpmIBU and tpmFLU ligands and corresponding complexes 3 and 4 were characterized by IR and multinuclear NMR spectroscopy, and the structure of tpmIBU was elucidated by single crystal X-ray diffraction. Complexes 1–4 were also assessed for their behaviour in aqueous media (solubility in D2O, octanol/water partition coefficient, stability in physiological-like conditions). The antiproliferative activity of ligands and complexes was determined on A2780, A2780cis and A549 cancer cell lines and the non-cancerous HEK 293T and BJ cell lines. The ligands and complexes were investigated for their ability to inhibit COX-2 (cyclooxygenase) and HNE (4-hydroxynonenal) enzymes. Complexes 3 and 4 exhibited cytotoxicity that may be attributed predominantly to their bioactive fragments, while DNA binding and enhancement of ROS production do not appear to play any significant role. [ABSTRACT FROM AUTHOR]

In the synthesis of metal–organic frameworks (MOFs), the choice of the metal precursor plays a key role because of the influence that it can exert on the crystallization kinetics. The present work explores the use of metal-carbamato complexes for the synthesis of benchmark MOFs, namely HKUST-1 and UiO-66. Cu2(O2CNEt2)4·2NHEt2 and Zr(O2CNEt2)4, prepared using straightforward CO2 fixation reactions starting from the corresponding metal chlorides and diethylamine, were employed as metal precursors for MOF formation. The synthesis conditions, including the solvent, temperature, and ligand protonation degree, were systematically investigated, revealing metal carbamates as highly reactive precursors due to their prompt release of CO2 and amine upon reaction with protic species, i.e., the polycarboxylic linkers. This property of metal carbamates allowed us to identify room temperature protocols to achieve MOFs with comparable properties to those obtained using traditional metal precursors. Subsequent optimization of the reaction conditions led to the design of a one-pot synthetic strategy for HKUST-1, starting directly from copper(II) chloride and diethylamine under a CO2 atmosphere. The MOFs were characterized using various techniques, including powder X-ray diffraction, N2 sorption analysis, 1H nuclear magnetic resonance spectroscopy, and CHN elemental analysis, and compared to reference samples prepared according to literature procedures. [ABSTRACT FROM AUTHOR]

We conducted a joint synthetic, spectroscopic and computational study to explore the reactivity towards cyanide (from Bu4NCN) of a series of dinuclear complexes based on the M2Cp2(CO)3 scaffold (M = Fe, Ru; Cp = η5-C5H5), namely [M2Cp2(CO)2(µ-CO){µ,η1:η2-CH=C=CMe2}]BF4 (1Fe-Ru), [Ru2Cp2(CO)2(µ-CO){µ,η1:η2-C(Ph)=CHPh}]BF4 (2Ru) and [M2Cp2(CO)2(µ-CO){µ-CN(Me)(R)}]CF3SO3 (3Fe-Ru). While the reaction of 1Fe with Bu4NCN resulted in prevalent allenyl deprotonation, preliminary CO-NCMe substitution in 1Ru enabled cyanide addition to both the allenyl ligand (resulting in the formation of a h1:h2-allene derivative, 5A) and the two metal centers (affording 5B1 and 5B2). The mixture of 5B1-2 was rapidly converted into 5A in heptane solution at 100 °C, with 5A being isolated with a total yield of 60%. Following carbonyl-chloride substitution in 2Ru, CN− was incorporated as a terminal ligand upon Cl− displacement, to give the alkenyl complex 6 (84%). The reactivity of 3Fe and 3Ru is strongly influenced by both the metal element, M, and the aminocarbyne substituent, R. Thus, 7aRu was obtained with a 74% yield from cyanide attack on the carbyne in 3aRu (R = Cy, cyclohexyl), whereas the reaction involving the diiron counterpart 3aFe yielded an unclean mixture of the metastable 7aFe and the CO/CN− substitution product 8aFe. The cyano-alkylidene complexes 7aRu (R = Cy) and 7bFe (R = Me) underwent CO loss and carbene to carbyne conversion in isopropanol at 60–80 °C, giving 8aRu (48%) and 8bFe (71%), respectively. The novel compounds 5A, 5B1-2, 6 and 7aRu were characterized by IR and NMR spectroscopy, with the structure of 7aRu further elucidated by single crystal X-ray diffraction analysis. Additionally, the DFT-optimized structures of potential isomers of 5A, 5B1-2 and 6 were calculated. [ABSTRACT FROM AUTHOR]

We present a new synthetic strategy for obtaining mixed-valence triiron complexes where the metal centers are bridged by a novel, highly functionalized hydrocarbyl ligand. The alkynyl–vinyliminium complexes [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(X–C≡CH)CHCNMe2}]CF3SO3 (X = 4-C6H4, [2a1]CF3SO3; X = (CH2)3, [2a2]CF3SO3) were synthesized in almost quantitative yields from the aminocarbyne precursor [Fe2Cp2(CO)2(μ-CO){μ-CNMe2}]CF3SO3, [1a]CF3SO3, and the di-alkynes HC≡C–X–C≡CH. Then, the ferracycle [Fe(Cp)(CO){C(NMe2)CH＝C(4-C6H4C≡CH)C(O)}], 4a1, was produced in 47% yield from the cleavage of [2a1]CF3SO3 promoted by pyrrolidine. Subsequent reactions of the acetonitrile adducts [Fe2Cp2(CO)(μ-CO)(NCMe){μ-CNMe(R)}]CF3SO3 (R = Me, [1aACN]CF3SO3; R = Xyl, [1bACN]CF3SO3) ([FeIFeI]) with 4a1 ([FeII]) at room temperature resulted in the formation of [FeIFeIFeII] complexes [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(X–C＝CHC(NMe2)＝FeCp(CO)C＝O)CHCNMe(R)}]CF3SO3 (R = Me, [5a1]CF3SO3; R = Xyl, [5b1]CF3SO3) in yields ranging from 56% to 64%. The new products were characterized by IR and multinuclear NMR spectroscopy, and the structures of [2a2]CF3SO3 and 4a1 were confirmed by single crystal X-ray diffraction. Cyclic voltammetry and spectroelectrochemical studies on [5a1]+ have revealed that reduction and oxidation events occur almost independently at the [FeIFeI] and [FeII] units, respectively. This observation underscores a minimal electronic interaction between the two fragments within the triiron complex. Accordingly, DFT studies pointed out that the HOMO and LUMO orbitals are predominantly localized in the two distinct compartments of [5a1]+. [ABSTRACT FROM AUTHOR]

While ruthenium(II) arene complexes have been widely investigated for their potential in catalytic transfer hydrogenation, studies on homologous compounds replacing the arene ligand with the six‐electron donor tris(1‐pyrazolyl)methane (tpm) are almost absent in the literature. The reactions of [RuCl(κ3‐tpm)(PPh3)2]Cl, 1, with a series of nitrogen ligands (L) proceeded with selective PPh3 mono‐substitution, affording the novel complexes [RuCl(κ3‐tpm)(PPh3)(L)]Cl (L=NCMe, 2; NCPh, 3; imidazole, 4) in almost quantitative yields. Products 2–4 were fully characterized by IR and multinuclear NMR spectroscopy, moreover the molecular structure of 4 was ascertained by single crystal X‐ray diffraction. Compounds 2–4 were evaluated as catalytic precursors in the transfer hydrogenation of a series of ketones with isopropanol as the hydrogen source, and 2 exhibited the highest activity. Extensive NMR experiments and DFT calculations allowed to elucidate the mechanism of the transfer hydrogenation process, suggesting the crucial role played by the tpm ligand, reversibly switching from tri‐ to bidentate coordination during the catalytic cycle. [ABSTRACT FROM AUTHOR]

Novel diiron vinyliminium complexes, [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(R3)＝CHC＝NMe(R2)}]CF3SO3 (2a–f; R2 = 4-C6H4OMe, Cy or Me; R3 = Cy, CH2Cy or 4-C6H4OMe; Cy = cyclohexyl, Cp = η5-C5H5), were synthesized by alkyne insertion reaction from the corresponding diiron aminocarbyne precursors, and isolated in 53–98% yields. The reactions of selected vinyliminium complexes with N2CHCO2Et and MeONa, followed by N-methylation, afforded the new hydrazone-vinyliminium [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(R3)C(NMeN＝CHCO2Et)CN(R1)(R2)}]X (4a–c; R1 = Me or CH2Ph; R2 = Cy, CH2Ph or Me; R3 = 4-C6H4OMe or Ph; X = NO3 or CF3SO3), in 53–67% yields. Compounds 2a–f and 4a–c were fully characterized by IR and multinuclear NMR spectroscopy, and the structures of 2a–c were ascertained by single crystal X-ray diffraction. Moreover, D2O solubility, Log Pow coefficients and the fraction of each complex preserved in aqueous media after 72 hours at 37 °C were determined by 1H NMR and UV-Vis methods. The antiproliferative activity of 2a–f and 4a–c was measured on the mouse colon CT26 and human glioblastoma U87 cancer cell lines, and on the retinal pigment epithelial RPE-1 non-cancerous cell line. Complexes 2a,d,e, which all bear R3 = Cy, stand out for their performance and their selectivity towards cancer cells. To give insight into the mechanism of action, the effect of 2a, 2d, 2e, 2f, 4b and 4c on the mitochondrial respiration was evaluated in CT26 cells (Seahorse Mito stress test), revealing a correlation between the effectiveness of the complexes and their influence on the mitochondrial metabolism. [ABSTRACT FROM AUTHOR]

Diiron μ-aminocarbyne complexes [Fe2Cp2(NCMe)(CO)(μ-CO){μ-CN(Me)(R)}]CF3SO3 (R = Xyl, [1aNCMe]CF3SO3; R = Me, [1bNCMe]CF3SO3; R = Cy, [1cNCMe]CF3SO3; R = CH2Ph, [1dNCMe]CF3SO3), freshly prepared from tricarbonyl precursors [1a–d]CF3SO3, reacted with NaOCN (in acetone) and NBu4SCN (in dichloromethane) to give [Fe2Cp2(kN-NCO)(CO)(μ-CO){μ-CN(Me)(R)}] (R = Xyl, 2a; Me, 2b; Cy, 2c) and [Fe2Cp2(kN-NCS)(CO)(μ-CO){μ-CN(Me)(CH2Ph)}], 3 in 67–81% yields via substitution of the acetonitrile ligand. The reaction of [1aNCMe–1cNCMe]CF3SO3 with KSeCN in THF at reflux temperature led to the cyanide complexes [Fe2Cp2(CN)(CO)(μ-CO){μ-CNMe(R)}], 6a–c (45–67%). When the reaction of [1aNCMe]CF3SO3 with KSeCN was performed in acetone at room temperature, subsequent careful chromatography allowed the separation of moderate amounts of [Fe2Cp2(kSe-SeCN)(CO)(μ-CO){μ-CN(Me)(Xyl)}], 4a, and [Fe2Cp2(kN-NCSe)(CO)(μ-CO){μ-CN(Me)(Xyl)}], 5a. All products were fully characterized by elemental analysis, IR, and multinuclear NMR spectroscopy; moreover, the molecular structure of trans-6b was ascertained by single crystal X-ray diffraction. DFT calculations were carried out to shed light on the coordination mode and stability of the {NCSe-} fragment. [ABSTRACT FROM AUTHOR]

Dimetallic complexes are suitable platforms for the assembly of small molecular units, and the reactivity of bridging alkenyl ligands has been widely investigated to model C–C bond forming processes. Here, we report the unusual coupling of an alkenyl ligand, bridging coordinated on a diruthenium scaffold, with a series of alkynes, revealing two possible outcomes. The diruthenium complex [Ru2Cp2(Cl)(CO)(μ-CO){μ–η1:η2-C(Ph)＝CH(Ph)}], 2, was prepared in two steps from [Ru2Cp2(CO)2(μ-CO){μ–η1:η2-C(Ph)＝CH(Ph)}]BF4, [1]BF4, in 69% yield. Then, the reaction of 2 with C2(CO2Me)2, promoted by AgCF3SO3 in dichloromethane, afforded in 51% yield the complex [Ru2Cp2(CO)2{μ–η3:η2-C(Ph)CH(Ph)C(CO2Me)C(CO2Me)}]CF3SO3, [3]CF3SO3, containing a ruthenacyclopentene-based hydrocarbyl ligand. On the other hand, 2 reacted with other alkynes and AgX salts to give the butadienyl complexes [Ru2Cp2(CO)2{μ–η3:η2-C(R)CH(R′)C(Ph)C(Ph)}]X (R = R′ = H, [4]BF4; R = R′ = Me, [5]CF3SO3; R = R′ = Ph, [6]CF3SO3; R = Ph, R′ = H, [7]CF3SO3), in 42–56% yields. All products were characterized by IR and NMR spectroscopy, and by single crystal X-ray diffraction in the cases of 2, [3]CF3SO3 and [6]BF4. DFT calculations highlighted the higher stability of [4–7]+-like structures with respect to the corresponding [3]+-like isomers. It is presumable that [3]+-like isomers initially form as kinetic intermediates, then undergo H-migration which is disfavoured in the presence of carboxylato substituents on the alkyne. Such hypothesis was supported by the computational optimization of the transition states for H-migration in the cases of R = R′ = H and R = R′ = CO2Me. [ABSTRACT FROM AUTHOR]

Novel titanium alkoxide‐carbamate complexes, i. e. [Ti(OiPr)2(O2CNR2)2]m (R=Et, 1; R=iPr, 2; R=Bn=CH2Ph, 3), were synthesized in 87–94 % yields by using two distinct synthetic approaches, i. e. the reaction of [Ti(OiPr)4] with [Ti(O2CNR)4] (1 : 1 molar ratio) in dichloromethane solution, and the addition of [Ti(OiPr)4] to amine/CO2 mixture in toluene (amine/Ti ratio=2). The liquid products 1–3 were characterized by elemental analysis, IR and NMR spectroscopy, and the structure of 1 was optimized by DFT calculations. Combined, experimental and theoretical outcomes suggest a trinuclear structure for 1–3, with the carbamates acting as bridging bidentate ligands. Compound 2 revealed the most effective of the series in promoting the oxidation of a series of organic sulfides into the corresponding sulfones, working generally better than 1 and 3 and the homoleptic counterparts [Ti(OiPr)4] or [Ti(O2CNEt2)4]. However, [Ti(OiPr)4] exhibited the best performance in the conversion of tetrahydrothiophene to tetrahydrothiophene 1,1‐dioxide, instead [Ti(O2CNEt2)4] was the most suitable catalyst for the mono‐oxygenation of dibenzylsulfide. NMR and DFT studies indicate that mononuclear bis‐methanol adducts, bearing the solvent molecules trans‐located with respect to the isopropoxides, are plausible active species in the catalytic cycle. [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]

The room temperature reactions with internal alkynes, RC≡CR, of the μ-allenyl acetonitrile complex [Ru2Cp2(CO)2(NCMe){μ–η1:η2-C1H＝C2＝C3Me2}]BF4 (1-NCMe), freshly prepared from the tricarbonyl precursor [Ru2Cp2(CO)3{μ–η1:η2-C1H＝C2＝C3Me2}]BF4, 1, proceeded with alkyne insertion into ruthenium-allenyl bond and allenyl-CO coupling, affording compounds [Ru2Cp2(CO)2{μ–η2:η5-C(R)C(R)C1HC2(C3Me＝CH2)C(OH)}]BF4 (R = Ph, 2; R = CO2Me, 3; R = CO2Et, 4) in 83–94% yields. Deprotonation of 2–4 by triethylamine gave [Ru2Cp2(CO)2{μ–η2:η5-C(R)C(R)CHC(CMe＝CH2)C(O)}] (R = Ph, 5; R = CO2Me, 6; R = CO2Et, 7) in 75–88% yields, and 2–4 could be recovered upon HBF4·Et2O addition to 5–7. All the products, 2–7, were fully characterized by elemental analysis, IR and multinuclear NMR spectroscopy. The structure of 2 was ascertained by single crystal X-ray diffraction and investigated by DFT calculations, revealing a six-membered ruthenacycle with Shannon aromaticity index in line with related compounds. The formation of ruthenium-coordinated ruthenabenzenes from a preexistent diruthenium scaffold is a versatile but underdeveloped approach exploiting cooperative effects typical of a dimetallic core. [ABSTRACT FROM AUTHOR]

The reactions of the dimeric complexes [RuX2(η6-p-cymene)]2 (X = Br, I, SCN) with L -proline (ProH) and trans-4-hydroxy- L -proline (HypH), in methanol in the presence of NaOH, afforded [RuX(κ2N,O-Pro)(η6-p-cymene)] (X = Br, 1b; I, 1c; SCN, 1d) and [RuX(κ2N,O-Hyp)(η6-p-cymene)] (X = Br, 2b; I, 2c; SCN, 2d), respectively. Alternatively, the one-pot, sequential addition of the appropriate α-amino carboxylate and X− salt to [RuCl2(η6-p-cymene)]2 led to [RuX(κ2N,O-Pro)(η6-p-cymene)] (X = N3, 1e; NO2, 1f; CN 1g) and [Ru(N3)(κ2N,O-Hyp)(η6-p-cymene)] (2e). Complexes [Ru(κ3N,O,O′-O2CCH(NH2)(R)O)(η6-p-cymene)] (R = CH2, 3h; R = CHMe, 4h; R = CH2CH2, 5h) were prepared from the reaction of [RuCl2(η6-p-cymene)]2 with the appropriate α-amino acid and NaOH in refluxing isopropanol. Treatment of the L -serine (SerH2) derivative [RuCl(κ2N,O-SerH)(η6-p-cymene)] (3a) with 1,3,5-triaza-7-phosphaadamantane (PTA) in water at reflux produced [Ru(κ2N,O-Ser)(κP-PTA)(η6-p-cymene)]Cl ([3i]Cl). The products were isolated in good to excellent yields, and were characterized by elemental analysis, IR and multinuclear NMR spectroscopy. The structures of 1f and 2b–e were ascertained by X-ray diffraction studies. The behaviour of the complexes in water and cell culture medium was investigated by multinuclear NMR and UV-Vis spectroscopy, revealing a considerable influence of the monodentate ligand on the aqueous chemistry. Complexes 1d–e, 2d–e, 3h, 4h and [3i]Cl, showing substantial inertness in aqueous media, were assessed for their cytotoxicity towards A2780 and A2780cisR cancer cell lines and the noncancerous HEK 293T cell line. A selection of compounds was also investigated for Ru uptake in A2780 cells and interactions with cytochrome c as a model protein. Combined, these studies provide insights into the previously debated role of the 'leaving' ligand on the biological activity of Ru(II) arene α-amino acid complexes. [ABSTRACT FROM AUTHOR]

A series of diiron complexes with two cyclopentadienyls, two carbonyls, and one bridging vinyl‐aminoalkylidene as ligands, [3a–h]CF3SO3 and [4a–d]CF3SO3, was synthesized in 66–94% yields from diiron μ‐aminocarbyne precursors. The subsequent reactions with pyrrolidine led to selective fragmentation to aminoalkylidene‐ferracyclopentenone derivatives (5a–h and 6a–c) in 30–84% yields. The compounds were characterized by elemental analysis, Fourier transform infrared and NMR spectroscopy, and by single crystal X‐ray diffraction in three cases. The stability in aqueous media relevant to biological trials, the carbon monoxide release, and the catalytic activity in NADH oxidation were evaluated for selected compounds by NMR spectroscopy and gas chromatography. The in vitro antiproliferative activity of the compounds was determined towards cancer (A2780, A2780cisR) and noncancer (HEK‐293) cell lines. Moreover, the antibacterial activity was tested on Gram‐positive (vancomycin‐resistant E. faecium and methicillin‐resistant S. aureus) and Gram‐negative strains (A. baumannii and P. aeruginosa). [ABSTRACT FROM AUTHOR]

The development of sustainable synthetic routes to access valuable oxazolidinones via CO2 fixation is an active research area, and the aziridine/carbon dioxide coupling has aroused a considerable interest. This reaction features a high activation barrier and thus requires a catalytic system, and may present some other critical issues. Here, the straightforward gram‐scale synthesis of a series of 5‐aryl‐2‐oxazolidinones was developed at ambient temperature and atmospheric CO2 pressure, in the absence of any catalyst/co‐catalyst. The key to this innovative procedure consists in the direct transfer of the pre‐formed amine/CO2 adduct (carbamate) to common aziridine precursors (dimethylsulfonium salts), replacing the classical sequential addition of amine (intermediate isolation of aziridine) and then CO2. The reaction mechanism was investigated by NMR spectroscopy and DFT calculations applied to model cases. [ABSTRACT FROM AUTHOR]

The diiron µ‐vinyliminium compounds [Fe2Cp2(CO)(µ‐CO){µ‐η1:η3‐C3HC2HC1NMe(R)}]CF3SO3 (R = Me, 2a; R = Xyl = 2,6‐C6H3Me2, 2b; Cp = η5‐C5H5) reacted with grey selenium, in the presence of sodium methoxide, to give the corresponding Se‐functionalized derivatives [Fe2Cp2(CO)(µ‐CO){µ‐η1:η3‐C3HC2(Se)C1NMe(R)}], 3a–b, in ca. 50 % yields. The monoiron zwitterionic complex [FeCp(CO){SeC1(NMe2)C2HC3H}], 4, was obtained as a side‐product (31 %) of the reaction leading to 3a. The treatment of 3b with S8/NaOMe afforded the 2‐ferra‐thiophene [FeCp(CO){SC3HC2HC1NMe(Xyl)}], 5, in 49 % yield. The straightforward reactions of 3a with a two‐fold excess of dialkylacetylenedicarboxylates led to functionalized 3‐amino‐selenophenes appended to the diiron frame through a bridging allylidene ligand, [Fe2Cp2(CO)(µ‐CO){µ‐η1:η3‐C7(CO2R)C6(CO2R)C3HC2SeC5(CO2R)C4(CO2R)C1(NMe2)}] (R = Me, 6a; R = Et, 6b; R = tBu, 6c), in approximately 50 % yields. The synthesis of 6a–c is the result of two distinct modes of reactivity exhibited by the alkyne reactant in one pot, i.e. 1,3‐dipolar cycloaddition to C and Se atoms and insertion into Fe‐µ‐alkylidene. All the products were characterized by means of elemental analysis, IR and multinuclear NMR spectroscopy, and the molecular structure of 6a was elucidated by a single‐crystal X‐ray diffraction study. [ABSTRACT FROM AUTHOR]

The reaction of pyrrolidine with a series of cationic diiron cyclopentadienyl complexes containing a bridging vinyliminium ligand gives access to piano stool monoiron complexes based on a five-membered metallacycle that includes a vinyl-aminoalkylidene moiety, in moderate to high yields. The resulting metallacyclic motif (aminoalkylidene-ferracyclopentenone) is unique in organometallic chemistry and is partially preconstructed on the dinuclear frame. The monoiron products were fully characterized by elemental analysis, IR and multinuclear NMR spectroscopy, and in a number of cases by X-ray diffraction and cyclic voltammetry. They are robust in aqueous solutions and generally unreactive towards alkylating agents in organic solvents. However, a cationic derivative was prepared in high yield by methylation of a 2-pyridyl group. The cytotoxicity of both neutral and ionic complexes was assessed on cancerous (A2780 and A280cisR) and non-cancerous (HEK293) cell lines, revealing the influence of local structural modifications on the antiproliferative activity and the selectivity of the compounds. [ABSTRACT FROM AUTHOR]

A sound synthetic procedure for the preparation of trans‐[PtBr(µ‐Br)(PPh3)]2 is described. The species was fully characterized and used to obtain [PtBr2(PPh3)(L)] complexes (L = DMSO, p‐toluidine, pyridine) by a bridge‐splitting reaction. All products were fully characterized by NMR spectroscopy, together with cis‐[PtBr2(PPh3)(NCCH3)], obtained as an intermediate in the synthesis of the dinuclear precursor. Cis‐[PtBr2(PPh3)(NCCH3)] was also studied by X‐ray diffraction. [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 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]

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 syntheses of new PtII complexes with 4-acyl-5-pyrazolones [HQPh = 1-phenyl-3-methyl-4-benzoylpyrazol-5-one, a; HQpy,CF3 = 1-(2-pyridyl)-3-methyl-trifluoroacetylpyrazol-5-one, b] are reported: trans-[PtCl2(DMSO)(HQPh)] ( 1a), cis-[PtCl2(DMSO)(HQPh)] ( 2a), [PtCl(DMSO)(Qpy,CF3)] ( 1b), and [PtCl2(KQpy,CF3)] ( 2b). All complexes were characterized by multinuclear (1H, 13C, 19F, and 195Pt), multidimensional NMR spectroscopy and single-crystal X-ray diffraction analyses. The isomer trans-[PtCl2(DMSO)(HQPh)] ( 1a) crystallizes in two polymorphic forms, which correspond to two different conformers. In the trans- syn conformer ( 1aM) (monoclinic, space group P21/ c), the H atom of the enol group [O(1)H(1)] establishes an intramolecular hydrogen bond with the ketone oxygen (O2), whereas in the trans- anti conformer ( 1aO) (orthorhombic, space group Pca21), the same groups are involved in an analogous intermolecular H bond. Interestingly, the cis isomer ( 2a) showed in solution and at room temperature slow rotation around both the Pt-N1 and the Pt-S bonds, which restrained both the acylpyrazolone and DMSO ligand motion. Moreover, the water solubility of the complexes trans- and cis-[PtCl2(DMSO)(HQPh)] ( 1a and 2a) and [PtCl2(KQpy,CF3)] ( 2b) allowed to perform in vitro biological assays on platinum-sensitive human endometrium (HeLa) and platinum-resistant human breast (MCF-7) cancer cell lines. It was also possible to compare their cytotoxicity to cisplatin. Interestingly, trans isomer 1a showed higher cytotoxicity on HeLa cells compared to the cis isomer 2a. [ABSTRACT FROM AUTHOR]

Abstract: Novel triorganotin(IV) derivatives of β-diketonate Q ligands (HQ in general, in detail HQfur =1-phenyl-3-methyl-4-(2-furancarbonyl)-pyrazol-5-one, HQthi =1-phenyl-3-methyl-4-(2-thienylcarbonyl)-pyrazol-5-one) of general formula (Q)SnR3·xH2O (R=Ph, x =0; R=Bu n or Me, x =1) have been synthesized and spectroscopically and thermally characterized. Triphenyltin(IV) complexes have been isolated as anhydrous compounds while trialkyltin(IV) are always monohydrated. The structures of (Qfur)SnPh3 and (Qthi)SnMe3(OH2) are recorded. The tin atoms are five-coordinate in both. In the first, the pyrazolonate ligand behaves as an O,O′-bidentate; there are two similar but independent molecules in the structure. In the quasi-trigonal-bipyramidal environments, Sn–O(acyl) are 2.478(3), 2.364(3), Sn–O(pyrazolonate) 2.050(2), 2.079(2), Sn–C 2.123(4)–2.162(3)Å with the longer O(acyl) and a phenyl group quasi-trans (O–Sn–C 162.5(1), 160.8(1)°). In (Qthi)SnMe3(OH2), the three methyl groups are equatorial (Sn–C 2.1259(9)–2.1380(8)Å); Sn–O(Qthi,OH2) are 2.2143(5), 2.3350(6)Å, O–Sn–O 175.36(2)°. Trimethyltin(IV) derivatives decompose on heating with release of H2O and SnMe4 and formation of (Q)2SnMe2. Decomposition occurs also within two days after dissolution of (Q)SnMe3(OH2) in chloroform. [Copyright &y& Elsevier]

Abstract: Coordination compounds of general formula MX4[κ2-O(R)CH2CH(R′)OR′′], 2a–i, have been prepared in high yield upon addition of a variety of 1,2-dialkoxyalkanes, ROCH2CH(R′)OR′′, to MX4 (M=Ti, X=F, 1a, I, 1b; M=Zr, X=Br, 1c, I, 1d). The new complexes have been characterized by elemental analysis and NMR spectroscopy. The thermal stability of 2 has been studied. Fragmentation of the TiI4 adducts takes place in chloroform solution at 90°C: after hydrolysis of the reaction mixtures, MeI and CH2ICH2I have been detected from TiI4[dme] [dme=MeO(CH2)2OMe], MeI and Me2O from TiI4[MeOCH2CH(Me)OMe], and MeI, CH2ICH2I, Me2O, CH2ClI from TiI4[MeO(CH2)2OCH2Cl]. The diether MeO(CH2)2OCH2Cl is thermally activated also when coordinated to ZrX4 (X=Br, I): after hydrolysis, MeBr, CH2BrCH2Br, O(CH2CH2Cl)2 and Me2O (X=Br) and MeI, CH2ClI and CH2ICH2I (X=I) have been found, respectively. [ABSTRACT FROM AUTHOR]

The salts [S(NMe2)3][MF6] (M = Nb, 2a; M=Ta, 2b) and [S(NMe2)3][M2F11] (M = Nb, 2c; M = Ta, 2d) have been prepared by reacting MF5 (M = Nb, 1a; M = Ta, 1b) with [S(NMe2)3][SiMe3F2] (TASF reagent) in the appropriate molar ratio. The solid state structure of 2b has been ascertained by X-ray diffraction. The 1:1 molar ratio reactions of 1a with a variety of organic compounds (L) give the neutral adducts NbF5L [L = Me2CO, 3a; L = MeCHO, 3b; L = Ph2CO, 3c; L = tetrahydrofuran (thf), 3d; L = MeOH, 3e; L = EtOH, 3f; L = HOCH2CH2OMe, 3g; L = Ph3PO, 3h; L = NCMe, 3i] in good yields. The complexes MF5L [M = Nb, L = HCONMe2, 3j; M = Nb, L = (NMe2)2CO, 3k; M = Ta, L = (NMe2)2CO, 3l; M = Nb, L = OC(Me)CH=CMe2, 3m] have been detected in solution in admixture with other unidentified products, upon 2:1 molar reaction of 1 with the appropriate reagent L. The ionic complexes [NbF4(tht)2][NbF6], 4a, and [NbF4(tht)2][Nb2F11], 4b, have been obtained by combination of tetrahydrothiophene (tht) and 1a, in 1:1 and 2:3 molar ratios, respectively. The treatment of 1 with a two-fold excess of L leads to the species [MF4L4][MF6] [M = Nb, L = HCONMe2, 5a; M = Ta, L = HCONMe2, 5b; M = Nb, L = thf, 5c; M = Ta, L = thf, 5d; M = Nb, L = OEt2, 5e]. The new complexes have been fully characterised by NMR spectroscopy. Moreover, the revised 19F NMR features of the known compounds MF5L [M = Ta, L = Me2CO, 3n; M = Ta, L = Ph2CO, 3o; M = Ta, L = MePhCO, 3p; M = Ta, L = thf, 3q; M = Nb, L = CH3CO2H, 3r; M = Nb, L = CH2ClCO2H, 3s; M = Ta, L = CH2ClCO2H, 3t], TaF4(acac), TaF4(Me-acac) and [TaF(Me-acac)3][TaF6] (Me-acac = methylacetylacetonato anion) are reported. [Copyright &y& Elsevier]

Abstract: A series of magnesium complexes of general formula [Mg(Tp x )2] (Tp x =Tp, Tp∗, Tp∗Cl, pzTp) and [Mg(Tp x )X] (X=Cl, Tp x =Tp t Bu or pz0Tp p -Tol; X=acetate, Tp x =Tp t Bu) were synthesised from magnesium chloride or acetate and M(Tp x ) (M=K, Na or Tl) in dichloromethane or alcoholic solution. These compounds are air-stable solids, sparingly soluble in most organic solvents; they have been characterized by elemental analysis, IR, 1H and 13C NMR spectra and, in selected cases, also by conductivity and molecular weight measurements. Single crystal X-ray diffraction studies of [Mg(Tp)2], [Mg(Tp*)2] and [Mg(Tp*Cl)2] show unsolvated neutral bis(tripod ligand)magnesium(II) molecules with six-coordinate magnesium atoms (〈Mg–N〉 2.167(6), 2.19(2), 2.205(4)Å). [Copyright &y& Elsevier]

Abstract: The preparation of a number of new 9-substituted octafluorofluorene derivatives, solution NMR studies, and the first examples of solid state structures of octafluorofluorenes [1,2,3,4,5,6,7,8-octafluorofluorene, C13H2F8, 1; 1,2,3,4,5,6,7,8-octafluoro-9-(pentafluoro)phenylfluorene, C19HF13, 8; 1,1′,2,2′,3,3′,4,4′,5,5′,6,6′,7,7′,8,8′-hexadecafluoro-9,9′-bifluorenyl, C26H2F16, 11] are reported. Variable temperature 19F NMR investigations have been performed on the 9-aryl substituted compounds 1,2,3,4,5,6,7,8-octafluoro-9-(pentafluoro)phenyl-9-hydroxyfluorene, C19HF13O, 4, 1,2,3,4,5,6,7,8-octafluoro-9-(nonafluoro-4′-biphenylyl)-9-hydroxyfluorene, C25HF17O, 5, and 8, and the energetic barriers to rotation of the aryl have been determined. A lower rotational barrier is observed for compound 4 with respect to compound 8, while 5 does not show fluxional behaviour below 338K. The results of the variable temperature experiments performed on 8 have been rationalized by 2D NMR studies, and compared to the solid state data resulting from the X-ray structural analysis. [Copyright &y& Elsevier]

Nitriles (N≡CR) are ubiquitous in coordination chemistry, yet literature studies on metal–nitrile bonding based on a multi-technique approach are rare. We selected an easily-available di-organoiron framework, containing both π-acceptor (CO, aminocarbyne) and donor (Cp = η5−C5H5) ligands, as a suitable system to provide a comprehensive description of the iron–nitrile bond. Thus, the new nitrile (2–12)CF3SO3 and the related imine/amine complexes (8–9)CF3SO3 were synthesized in 58–83% yields from the respective tris-carbonyl precursors (1a–d)CF3SO3, using the TMNO strategy (TMNO = trimethylamine-N-oxide). The products were fully characterized by elemental analysis, IR (solution and solid state) and multinuclear NMR spectroscopy. In addition, the structures of (2)CF3SO3, (3)CF3SO3, (5)CF3SO3 and (11)CF3SO3 were ascertained by single crystal X-ray diffraction. Salient spectroscopic data of the nitrile complexes are coherent with the scale of electron-donor power of the R substituents; otherwise, this scale does not match the degree of Fe → N π-back-donation and the Fe–N bond energies, which were elucidated in (2–7)CF3SO3 by DFT calculations. [ABSTRACT FROM AUTHOR]

Abstract: From the interaction between azole-type ligands L and AgX (X=NO3 or ClO4) or [AgX(PPh3) n ] (X=Cl, n =3; X=MeSO3, n =2), new ionic mononuclear [Ag(L)2]X and [Ag(PPh3)3L][X] or neutral mono-([Ag(PPh3) n L(X)]) or di-nuclear ([{Ag(PPh3)(L)(μ-X)}2]) complexes have been obtained which have been characterized through elemental analysis, conductivity measurements, IR, 1H NMR and, in some cases, also by 31P{1H} NMR spectroscopy, and single-crystal X-ray studies. Stoichiometries and molecular structures are dependent on the nature of the azole (steric hindrance and basicity), of the counter ion, and on the number of the P-donor ligands in the starting reactants. Solution data are consistent with partial dissociation of the complexes, occurring through breaking of both Ag–N and Ag–P bonds. [Copyright &y& Elsevier]

Adducts of the ligand bis(1,2,4-triazol-1-yl)methane (tz2(CH2)) of the form AgX:tz2(CH2):ER3:MeCN (1:1:1 :x) (X = NO3, R = Ph, E = P, As, or Sb, x = 1 or 2; X = NO2, ClO4, O3SCF3, E = P, R = Ph, x = 0, 1 or 2; X = NO3, ClO4, E = P, R = cy, x = 1; X = CIO4, E = As, R = Ph, x = 2) and AgNO3:ttz2(CH2):P(o-tolyl)3 (2:2:1) have been synthesized and characterized in the solid state and in solution by analyses, spectral (IR, far-IR, ¹H and 13C NMR, ESI MS data) data, and conductivity measurements. In the one-dimensional polymers (characterized by X-ray studies) AgNO3:tz2(CH2):PPh3:CH3CN (1:1:1:1), AgClO4:tz2(CH2):PPh3:CHsCN (1:1:1:2), AgNO3:tz2(CH2):AsPh3: CH3CN (1:1:1:2), and AgNO3:tz2(CH2):SbPh3:CH3CN (1:1:1:2), the silver atom can be regarded as four-coordinate, the tz2(CH2) ligands behaving as bridging groups rather than chelates, with no pair of ligands being dominant, quasi-trans, in their interactions. The AgNO3:tz2(CH2):P(o-tolyl)3 (2:2:1) adduct is a two-dimensional polymer containing two independent silver atoms, one four-coordinated unsymmetrically by a pair of triazolyl rings, one P(o-tolyl)3, and a unidentate nitrate and the second by a quasi-symmetrical O2NO chelate and a pair of equivalent triazolyl rings. [ABSTRACT FROM AUTHOR]

A series of 16 novel diiron complexes of general formula [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(R′)C(R″)CN(R)(Y)}]CF3SO3 (2–7), bearing different substituents on the bridging vinyliminium ligand, was synthesized in 69–95% yields from the reactions of diiron μ-aminocarbyne precursors with various alkynes. The products were characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy; moreover the X-ray structures of 2c (R = Y = CH2Ph, R′ = R″ = Me) and 3a (R = CH2CH=CH2, Y = R′ = Me, R″ = H) were ascertained by single-crystal X-ray diffraction studies. NMR and UV–Vis methods were used to assess the D2O solubility, the stability in aqueous solution at 37 °C and the octanol–water partition coefficients of the complexes. A screening study evidenced a potent cytotoxicity of 2–7 against the A2780 cancer cell line, with a remarkable selectivity compared to the nontumoral Balb/3T3 cell line; complex 4c (R = Cy, Y = R′ = R″ = Me) revealed as the most performant of the series. The antiproliferative activity of a selection of complexes was also assessed on the cisplatin-resistant A2780cisR cancer cell line, and these complexes were capable of inducing a significant ROS production. Moreover, ESI-MS experiments indicated the absence of interaction of selected complexes with cytochrome c and the potentiality to inhibit the thioredoxin reductase enzyme (TrxR). [ABSTRACT FROM AUTHOR]

Neutral [Ru(η6-arene)Cl2{Ph2P(CH2)3SPh-κP}] (arene = benzene, indane, 1,2,3,4-tetrahydronaphthalene: 2a, 2c and 2d) and cationic [Ru(η6-arene)Cl(Ph2P(CH2)3SPh-κP,κS)]X complexes (arene = mesitylene, 1,4-dihydronaphthalene; X = Cl: 3b, 3e; arene = benzene, mesitylene, indane, 1,2,3,4-tetrahydronaphthalene, and 1,4-dihydronaphthalene; X = PF6: 4a–4e) complexes were prepared and characterized by elemental analysis, IR, 1H, 13C and 31P NMR spectroscopy and also by single-crystal X-ray diffraction analyses. The stability of the complexes has been investigated in DMSO. Complexes have been assessed for their cytotoxic activity against 518A2, 8505C, A253, MCF-7 and SW480 cell lines. Generally, complexes exhibited activity in the lower micromolar range; moreover, they are found to be more active than cisplatin. For the most active ruthenium(II) complex, 4b, bearing mesitylene as ligand, the mechanism of action against 8505C cisplatin resistant cell line was determined. Complex 4b induced apoptosis accompanied by caspase activation. [ABSTRACT FROM AUTHOR]

A series of diiron/tetrairon compounds containing a S- or a Se-function (2a–d, 4a–d, 5a–b, 6), and the monoiron [FeCp(CO){SeC1(NMe2)C2HC3(Me)}] (3) were prepared from the diiron μ-vinyliminium precursors [Fe2Cp2(CO)(μ-CO){μ-η1: η3-C3(R')C2HC1N(Me)(R)}]CF3SO3 (R = R' = Me, 1a; R = 2,6-C6H3Me2 = Xyl, R' = Ph, 1b; R = Xyl, R' = CH2OH, 1c), via treatment with S8 or gray selenium. The new compounds were characterized by elemental analysis, IR and multinuclear NMR spectroscopy, and structural aspects were further elucidated by DFT calculations. The unprecedented metallacyclic structure of 3 was ascertained by single crystal X-ray diffraction. The air-stable compounds (3, 4a–d, 5a–b, 6) display fair to good stability in aqueous media, and thus were assessed for their cytotoxic activity towards A2780, A2780cisR, and HEK-293 cell lines. Cyclic voltammetry, ROS production and NADH oxidation studies were carried out on selected compounds to give insights into their mode of action. [ABSTRACT FROM AUTHOR]

The reaction of [(η 6 - p -cymene)RuCl(κ 2 N,O - l- serinate)], 1 , with CH 3 C(O)Cl/NEt 3 , in chloroform at reflux temperature, led to the serendipitous isolation of the dehydroacetate complex [(η 6 - p -cymene)RuCl(κ 2 O , O ′-dha)], 2 , in low amount. Then, dehydroacetic acid (dhaH) was prepared in one pot by self condensation of acetyl chloride in the presence of NEt 3 at room temperature, this reaction being unusual in the landscape of the chemistry of acyl chlorides. Complex 2 was synthesized in 89% yield from [(η 6 - p -cymene)RuCl 2 ] 2 and dhaH, and fully characterized by means of X-ray diffraction, IR and NMR spectroscopy. Complex 2 underwent fast and extensive dissociation of the dehydroacetate ligand in dmso/water solution, the degree of dissociation being substantially higher than that observed for the acetylacetonate ligand from [(η 6 - p -cymene)RuCl(κ 2 O , O ′-acac)], 3 . [ABSTRACT FROM AUTHOR]

Triphenylphosphine substitution reactions of [RuCl(PPh 3) 2 (tpm)]Cl, 1 , featuring tris(pyrazolyl)methane (tpm) as ligand, with the chlorambucil-decorated pyridine ligand Py CA , 3-aminopyridine (Py NH2 ) and 4-pyridinemethanol (Py OH ) afforded the corresponding pyridine complexes 2–4 in high yields. Py CA was preliminarily obtained via esterification of 4-pyridinemethanol with chlorambucil. The new compounds Py CA and 2–3 were characterized by IR and multinuclear NMR spectroscopy. Additionally, the structure of 3 was ascertained by single crystal X-ray diffraction. The in vitro anti-proliferative activity of 2–4 and Py CA was determined against a panel of cancer cell lines, outlining 2 as the most performing compound. Targeted studies were subsequently undertaken using 2 to elucidate mechanistic aspects, including the assessment of ruthenium cellular uptake, cell cycle arrest, production of reactive oxygen species (ROS), western blotting and DNA damage (comet test). Overall, data highlight that the anticancer activity provided by 2 primarily affects the mitochondria pathway with a potential additional contribution from DNA damage. The anticancer drug chlorambucil was conjugated with a robust ruthenium(II) tris-pyrazolylmethane scaffold through a pyridine ligand. The resulting complex exhibited strong cytotoxicity against cancer cell lines, attributed to disruption of mitochondria functionality and induction of DNA damage. [Display omitted] • Synthesis of new ruthenium-chlorambucil conjugate. • The resulting ruthenium-trispyrazolylmethane complex is highly stable in aqueous media. • Cytotoxicity data reveal favorable effect provided by conjugation. • Relate chlorambucil-lacking complexes have been analyzed for comparison. • Experiments have been carried out to elucidate the mode of action. [ABSTRACT FROM AUTHOR]

Silver(I) acylpyrazolonate derivatives of formula [Ag(Q)(R3P)]2 and [Ag(Q)(R3P)2], (QH=1-phenyl-3-methyl-4-R′(C&z.dbnd6;O)-pyrazol-5-one; QOH, R′=furane; QSH, R′=thiophene; R=Ph, Cy, o-tol), have been synthesised and characterised, both in the solid state and in solution. The derivatives [Ag(Q)(R3P)]2 contain dinuclear AgO2NP units with the acylpyrazolonate coordinating in a bridging O,O′-Q-N fashion. The [Ag(Q)(R3P)2] are tetrahedral species, with the distortion from ideal geometry increasing with the bulk of the phosphine. The [Ag(Q)(R3P)2] derivatives are fluxional in chloroform solution when R3P is sterically hindered (R=Cy or o-tol), dissociating partially to the [Ag(Q)(R3P)] fragment and free R3P. [Ag(QS)(Ph3P)]2 reacts with 1-methyl-2-mercaptoimidazole (Hmimt) affording the compound [Ag(Hmimt)(Ph3P)(QS)] and [Ag(QO)(Ph3P)]2 reacts with 1-methyl-imidazole (Meim) affording the compound [Ag(Meim)(Ph3P)(QO)], whereas [Ag(QS)(Ph3P)]2 reacts with 1,10-phenanthroline (phen), affording the compound [Ag(phen)(Ph3P)](QS). Finally [Ag(QS)(Ph3P)2] reacts with phen producing the ionic species [Ag(phen)(Ph3P)2](QS). [Copyright &y& Elsevier]

A sound synthetic procedure for the preparation of trans‐[PtBr(µ‐Br)(PPh3)]2 is described. The species was fully characterized and used to obtain [PtBr2(PPh3)(L)] complexes (L = DMSO, p‐toluidine, pyridine) by a bridge‐splitting reaction. All products were fully characterized by NMR spectroscopy, together with cis‐[PtBr2(PPh3)(NCCH3)], obtained as an intermediate in the synthesis of the dinuclear precursor. Cis‐[PtBr2(PPh3)(NCCH3)] was also studied by X‐ray diffraction. [ABSTRACT FROM AUTHOR]

The addition of Ph2P(2-C6H4OH) to [(η6-p-cymene)RuCl(µ-Cl)]2 led to the formation of three distinct products, depending on the experimental conditions. The previously reported [(η6-p-cymene)RuCl{ʎ2P,O-PPh2(2-C6H4O)}], 1, was obtained in 90% yield using MeOH as the solvent, in the presence of a base (Et3N). Conversely, [(η6-p-cymene)RuCl{ʎ2P,O-PPh2(2-C6H4OH)}]Cl, [2]Cl, was afforded (88% yield) in MeOH without using the base. However, [(η6-p-cymene)RuCl2{κP-PPh2(2-C6H4OH)}], 3, was the major species in chlorinated solvents. Compounds 1, [2]Cl, and 3 were characterized by analytical and spectroscopic (IR, NMR) methods. The X-ray structures of [2]+ and 3 were determined, with the latter forming hydrogen bond dimeric units in the solid state. The dissolution of [2]Cl into a series of deuterated solvents, except methanol, led to rapid equilibration between [2]Cl and 3, revealing the hemilabile behavior of the phosphino-phenol ligand. According to Pulsed-Field Gradient Spin Echo (PGSE)-NMR and DFT studies, the dimeric nature of 3 persists in solution; thus, the hydrogen-bonding properties of MeOH are crucial to stabilize [2]Cl with respect to 3, with the latter being 3.4 kcal mol-1 more stable than the former in the gas phase. Compound 1 underwent electrophilic additions by HCl, HBF4, and MeCOCl to give, respectively, [2]Cl (the reverse process being viable with Et3N), [2]BF4, and the ester [(η6-p-cymene)RuCl2{κP-PPh2(2-C6H4OCOMe)}], 5. The reaction of 1 with AgNO3 afforded the nitrate complex [(η6-p-cymene)Ru(NO3){ʎ2P,O-PPh2(2-C6H4O)}], 4. Compounds [2]BF4, 4, and 5 were isolated in the solid state in good to high yields and characterized by elemental analysis and IR and NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Dinuclear platinum(II) complexes [{PtCl 2 (PPh 3 )} 2 (μ-N–N)], where N–N is a divergent bidentate nitrogen ligand, were prepared by reacting cis -[PtCl 2 (PPh 3 )(NCMe)] with N–N in a Pt/N–N molar ratio 2. The ( trans , trans )-isomers were obtained as kinetic products and recovered in good yields and high purity { 1 , N–N = pyrazine (pyrz); 2 , N–N = 4,4′-bipyridyl (bipy); 3 , N–N = piperazine (pipz); 4 , N–N = p-xylylendiamine (xylN 2 )}. Cis -[PtCl 2 (PPh 3 )(NCMe)] was also reacted with the tridentate divergent ligand 2,4,6-tris-(pyrid-4′-yl)1,3,5-triazine (py3TRIA) in molar ratio 3 with formation of the trinuclear ( trans , trans , trans )-[{PtCl 2 (PPh 3 )} 3 (μ-py3TRIA)], 5 . On the other hand, the treatment of cis -[PtCl 2 (PPh 3 )(NCMe)] with the monodentate pyridine (py) produced a mixture of both trans -[PtCl 2 (PPh 3 )(py)] ( 6a ) and cis -[PtCl 2 (PPh 3 )(py)] ( 6b ). The reactions of cis -[PtCl 2 (PPh 3 )(NCMe)] with N–N = pyrz, bipy, pipz, carried out with a Pt/N–N molar ratio 1, were monitored by 31 P NMR spectroscopy. Equilibria were observed in solution, involving dinuclear ( trans – trans )-[{PtCl 2 (PPh 3 )} 2 (μ-N–N)], mononuclear [PtCl 2 (PPh 3 )(N–N)] and free N–N. The addition of an excess of the divergent ligand allowed the complete conversion to the corresponding mononuclear complexes. With the heteroaromatic ligands both geometric isomers were observed ( 7a , 7b and 8a , 8b , for pyrz and bipy derivatives, respectively) while with pipz the trans -isomer only was detected, 9 . In the system involving bipy, the scarcely soluble dinuclear ( cis , cis )-[{PtCl 2 (PPh 3 )} 2 (μ-bipy)], 2b , was also obtained. Products 2 , 2b , 3 ·2(CHCl 3 ) and 6a ·0.5(C 2 H 4 Cl 2 ) were structurally characterized by single crystal X-ray diffraction methods. [ABSTRACT FROM AUTHOR]

[Display omitted] The unprecedented cyanylation of an isocyanide ligand was achieved on a diiron scaffold using cyanogen bromide, and led to the first structural characterization of a N -cyano substituted aminoalkylidene ligand. • Aminoalkylidyne ligands are ubiquitous in organometallic chemistry. • N -cyano-aminoalkylidene ligands were unknown up to now. • Cyanylation reactions on metal complexes are usually hampered by competitive oxidation/bromination pathways. • Cyanogen bromide reacted as both CN+ and CN– transferor towards an isocyanide ligand in diiron complex. • The first structural characterization of a N -cyano-aminoalkylidene complex is reported. The reaction of the isocyanide complex [Fe 2 Cp 2 (CO) 3 (CNMe)], 1Me , with BrCN (1.2 eq.), in acetonitrile at 60 °C, led to the low-yield isolation, after work-up, of the unprecedented N -methylcyanamido-(cyano)alkylidene complex [Fe 2 Cp 2 (CO) 3 {μ-C(CN)N(CN)Me}], 3. The synthesis of 3 represents an uncommon example of C C bond forming cyanylation reaction taking place at a metal complex despite competitive oxidative addition pathways; it proceeded with the presumable, intermediate formation of a N -methylcyanamido-alkylidyne precursor readily undergoing CN– addition, and was accompanied by the production of minor amounts of [Fe 2 Cp 2 (CO) 4 ] and monoiron(II) piano-stool compounds. Compound 3 was fully characterized by single crystal X-ray diffraction, elemental analysis, IR and NMR spectroscopy. The reaction of [Fe 2 Cp 2 (CO) 4 ] with cyanogen bromide, under conditions resembling those employed for 1Me /BrCN, afforded a mixture of [FeCpBr(CO) 2 ] and [FeCp(CN)(CO) 2 ]. [ABSTRACT FROM AUTHOR]

The propen-2-yl-dimetallacyclopentenone complex [Fe2Cp2(CO)(μ-CO){μ-η1:η3-Cα(H)＝Cβ(Cγ(CH3)CH2)C(＝O)}] (1) underwent electrophilic additions at the propenyl moiety to afford the μ-allenyl complexes [Fe2Cp2(CO)2(μ-CO){μ-η1:η2α,β-CαH＝CβCγ(CH3)(CH2E)}][BF4] (E = CPh3, [2][BF4]; E = H, [3][BF4]), in ca. 85% yield. The molecular structure of ([2][BF4]) was ascertained by X-ray diffractometry; X-ray, NMR and DFT results agreed in that one single isomer formed, bearing the [CH2CPh3] group pointing far from the Fe–Fe axis. The reaction of [3][BF4] with NHEt2 in the presence of PhSSPh resulted in the prevalent formation of [FeCp(CO)2SPh] (7). [ABSTRACT FROM AUTHOR]

Abstract: New (Q)2SnR2 derivatives (HQ in general; in detail: =4-diphenylacetyl-3-methyl-1-phenyl-5-pyrazolone; HQBn =3-methyl-1-phenyl-4-phenylacetyl-5-pyrazolone; HQnaph =3-methyl-4-naphthoyl-1-phenyl-5-pyrazolone; R=CH3, C2H5, C6H11, n- and t-C4H9, C6H5,) have been synthesised and characterised by analytical and spectral techniques. Variable temperature NMR studies of derivatives (R=CH3 and C2H5) in chlorohydrocarbon solvents indicate a fluxional behaviour, with rapid interconversion between six- and five-coordinate species, the latter containing a bidentate acylpyrazolonate and a monodentate one. The X-ray crystal structures of the diorganotin(IV) derivatives , , (QBn)2SnMe2 and , inclusive of a representative of each Q x family, show the metal centres in a skewed trans octahedral configuration. The 4-acyl moiety of the β-diketonate donor exerts a steric effect which is correlated to structural behaviour in the solid and solution state. A solid state 119Sn CPMAS NMR study of the (QBn)2SnR2 (R=CH3, C2H5, t-C4H9 and C6H5) complexes shows a marked deshielding effect and upfield movement of the 119Sn isotropic chemical shift (δ iso) through this series. The 119Sn chemical shift spans (Ω) are the largest reported for directly oxo-coordinated Sn(IV) systems, although the markedly reduced Ω value for the (QBn)2SnPh2 complex may be indicative of a cis octahedral coordination, in contrast to the trans octahedral coordination characterising the other complexes of this suite. [Copyright &y& Elsevier]

The long-time known reactivity of [Fe 2 Cp 2 (CO) 4 ] with isocyanides has been revisited with the aim of preparing, isolating and structurally characterizing the mono-substituted products. [Display omitted] • Good yields of [Fe 2 Cp 2 (CO) 3 (CNR)] have been obtained from [Fe 2 Cp 2 (CO) 4 ] and isocyanides. • The use of a molar excess of the diiron reactant avoids polysubstitution. • The coordination mode of the isocyanide is scarcely influenced by the environment. The reactions of [Fe 2 Cp 2 (CO) 4 ] with a series of isocyanides, CNR, were conducted in acetonitrile and afforded, after a thermal treatment, the mono-isocyanide derivatives [Fe 2 Cp 2 (CO) 3 (CNR)] [R = 1H-indol-5-yl, 1 ; CH 2 P(O)(OEt) 2 , 2 ; Cy = C 6 H 11 , 3 ; 4-C 6 H 4 OMe, 4 ; Xyl = 2,6-C 6 H 3 Me 2 , 5 ; Me, 6 ; 2-naphthyl, 7 ; Bn = CH 2 Ph, 8 ]. In order to avoid multiple substitution, the diiron reactant was used in a molar excess with respect to the isocyanide (1.6 equivalents; 1.1 for the synthesis of 8). The products were separated from unreacted [Fe 2 Cp 2 (CO) 4 ] by chromatography or via reversible protonation, and finally isolated in 50–83% yields. IR and NMR spectroscopy indicate that the isocyanide ligand is bridging coordinated in 2 and 7 , terminal in 3 and 5 , while in the remaining cases a mixture of terminal- and bridging-CNR isomers is obtained. The molecular structure of 5 was ascertained by X-ray diffraction. In general, the coordination mode of the isocyanide is scarcely influenced by the environment (solvents with different polarities, solid state). Sluggish partial isocyanide migration from terminal to bridging position was recognized for 3 and 5 upon heating in refluxing toluene, a process which was reproduced by DFT calculations. [ABSTRACT FROM AUTHOR]