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1.
ACS Appl Mater Interfaces ; 11(40): 36886-36894, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31522492

RESUMO

Developing molecular circuits that can function as the active components in electrical devices is an ongoing challenge in molecular electronics. It demands mechanical stability of the single-molecule circuit while simultaneously being responsive to external stimuli mimicking the operation of conventional electronic components. Here, we report single-molecule circuits based on spiropyran derivatives that respond electrically to chemical and mechanical stimuli. The merocyanine that results from the protonation/ring-opening of the spiropyran form showed single-molecule diode characteristics, with an average current rectification ratio of 5 at ±1 V, favoring the orientation where the positively charged end of the molecule is attached to the negative terminal of the circuit. Mechanical pulling of a single spiropyran molecule drives a switch to a more conducting merocyanine state. The mechanical switching is enabled by the strong Au-C covalent bonding between the molecule and the electrodes, which allows the tensile force delivered by the STM piezo to break the molecule at its spiropyran C-O bond.

2.
Acta Crystallogr E Crystallogr Commun ; 75(Pt 8): 1209-1214, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31417794

RESUMO

The monocation product of the oxidative condensation-cyclization between two mol-ecules of pyridine-2-carbaldehyde and one mol-ecule of CH3NH2·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridinium, was isolated in the presence of metal ions as bis-[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] tetra-iodo-cadmate, (C13H12N3)2[CdI4], (I), and the mixed chloride/nitrate salt, bis-[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] 1.5-chlor-ide 0.5-nitrate trihydrate, 2C13H12N3 +·1.5Cl-·0.5NO3 -·3H2O, (II). Hybrid salt (I) crystallizes in the space group P21/n with two [L]2[CdI4] mol-ecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetra-halometallate anions are stacked parallel to the ab plane. Anti-parallel L + cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetra-hedral CdI4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis; the one-dimensional hydrogen-bonded polymer built of chloride ions and water mol-ecules runs parallel to a column of stacked cations.

3.
Dalton Trans ; 48(41): 15613-15624, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31408065

RESUMO

The synthesis, structural and photophysical characterisation of four tricarbonyl rhenium(i) complexes bound to 1,10-phenanthroline and a tetrazolato ancillary ligand are reported. The complexes are differentiated by the nature (hydroxy or methoxy) and position (meta or para) of the substituent attached to the phenyl ring in conjugation to the tetrazole ring. The complexes exhibit phosphorescence emission from triplet charge transfer excited states, with the maxima around 600 nm, excited state lifetime decays in the 200-300 ns range, and quantum yield values of 4-6% in degassed acetonitrile solutions. The nature and position of the substituent does not significantly affect the photophysical properties, which remain unchanged even after deprotonation of the hydroxide group on the phenol ring. The interpretation of the photophysical data was further validated by resonance Raman spectroscopy and time-dependent density functional theory calculations. All the complexes are internalised within cells, albeit to variable degrees. As highlighted by a combination of flow cytometry and confocal microscopy, the species display diffuse cytoplasmic localisation except for the complex with the hydroxy functional group at the para position, which reveals lower accumulation in cells and more pronounced punctate staining. Overall, the complexes displayed low levels of cytotoxicity.


Assuntos
Complexos de Coordenação/química , Fenol/química , Rênio/química , Tetrazóis/química , Animais , Complexos de Coordenação/toxicidade , Ligantes , Camundongos , Modelos Moleculares , Conformação Molecular , Prótons , Teoria Quântica , Células RAW 264.7
4.
Dalton Trans ; 48(30): 11278-11284, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31268102

RESUMO

The novel organic-inorganic hybrid salt [L]2[CoCl4] (1) and molecular complex [CoLCl3] (2), where L+ is 2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridinium cation, feature simple {CoCl4} and {CoCl3N} tetrahedral environments of negligible (1) and a slightly higher distortion (2) that are responsible for rather low positive magnetic anisotropy of CoII ion with D/hc = 12.1(6) (1) and 19.4(15) cm-1 (2). Both compounds exhibit field-induced slow magnetic relaxation with three relaxation channels [low- (LF), intermediate- and high-frequency (HF) modes] that is frequency and field dependent. With the increased DC field, the peaks referring to the LF relaxation path are moved to lower frequencies so that the applied DC field causes prolongation of the relaxation time. The opposite is true for the HF relaxation branch: the peak is moved to higher frequencies. Considering the simplicity of the coordination environment and moderate magnetic anisotropy of the metal ion in 1 and 2, the compounds are unique with respect to the remarkably long relaxation time for a given applied DC field and temperature: τLF = 0.54(4) s at BDC = 1.0 T and T = 2.0 K for 1, and τLF = 1.8(2) s at BDC = 1.2 T and T = 1.9 K for 2.

5.
Acta Crystallogr E Crystallogr Commun ; 75(Pt 5): 620-623, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31110799

RESUMO

The structure of the title compound, [Ni2(C9H10NO2)4], is built up by discrete centrosymmetric dimers. Two nitro-gen and three oxygen atoms of two Schiff base ligands singly deprotonated at the phenolate site form a square-pyramidal environment for each metal atom. The ligands are bonded differently to the metal centre: one of the phenolic O atoms is bound to one nickel atom, whereas another bridges the two metal atoms to form the dimer. The Ni-N/O distances fall in the range 1.8965 (13)-1.9926 (15) Å, with the Ni-N bonds being slightly longer; the fifth contact of the metal to the bridging phenolate oxygen atom is substanti-ally elongated [2.533 (1) Å]. A similar coordination geometry was observed in the isomorphous Cu analogue previously reported by us [Sydoruk et al. (2013 ▸). Acta Cryst. E69, m551-m552]. In the crystal, the [Ni2 L 4] mol-ecules form sheets parallel to the ab plane with the polar meth-oxy groups protruding into the inter-sheet space and keeping the sheets apart. Within a sheet, the mol-ecules are stacked relative to each other in such a way that the Ni2O2 planes of neighbouring mol-ecules are orthogonal.

6.
Inorg Chem ; 58(6): 3789-3799, 2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30835116

RESUMO

Several trinuclear ferrocenes are obtained by Friedel-Crafts reaction of octamethylferrocene with ferrocenoyl chloride and subsequent modifications. 1,1'-Diferrocenoyloctamethylferrocene (3) is transformed to the divinyl derivative (4a) by reaction with MeLi and AlCl3. The reactive 4a cyclizes spontaneously to a [4]ferrocenophane with buta-1,3-diene handle (5) or in the presence of AlCl3 to a [3]ferrocenophane with propene handle (6). Structure assignments are supported by X-ray crystallography and NMR spectroscopy, and mechanisms are proposed. Electrochemical behavior of the compounds was investigated with cyclic voltammetry, and assignments of the redox processes were carried out with the aid of density functional theory calculations. The synthesized compounds and demonstrated transformations represent useful tools for preparation of materials for charge-transport studies in metal-molecule-metal junctions.

7.
Acta Crystallogr E Crystallogr Commun ; 74(Pt 11): 1532-1535, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30443374

RESUMO

The title compound, [CoCd(C9H10NO2)3Cl2]·H2O, is a solvatomorph of the corresponding hemihydrate recently published by us [Nesterova et al. (2018 ▸). Appl. Cat. A, 560, 171-184]. The current structure reveals different cell parameters and space group compared with the published one while both are monoclinic with almost the same cell volume. The title compound is formed of discrete neutral dinuclear mol-ecules with no crystallographically imposed symmetry and water mol-ecules of crystallization. The overall geometry about the cobalt(III) ion is octa-hedral with an N3O3 environment; each ligand acts as a meridional ONO donor. The CdII coordination sphere approximates an irregular square pyramid with a chlorine atom at the apex. There is significant shortening of a Cd-O bond length to the oxygen atom of the methoxo group on one of the ligands [2.459 (3) Å] compared to the corresponding distance in the published structure [2.724 (7) Å], while other Cd-Cl/N/O bonds remain roughly the same. In the crystal lattice, the heterometallic mol-ecules, which are related by the crystallographic n-glide plane and inter-linked by weak hydrogen bonds to solvent water mol-ecules, form columns along [101]. Adjacent columns lie anti-parallel to each other.

8.
Chem Commun (Camb) ; 54(69): 9647-9650, 2018 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-30101241

RESUMO

Herein we report a new class of G-quadruplex stabilising ligands, multicarbazoles, which display high G-quadruplex DNA selectivity in the presence of 250 times excess duplex DNA. We report the synthesis of these compounds in moderate to high yields. Ligands in the series with optimal G-quadruplex selectivity contain an N-propylamino chain length where the amino functionalities are either pyrrolidine or piperidine.

9.
Dalton Trans ; 47(35): 12345-12352, 2018 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-30118135

RESUMO

Isomorphous ß-triketonate-based lanthanoid polymers containing tris(4-methylbenzoyl)methanide (mtbm) and Rb+ with formula {[Ln(Rb)(mtbm)4]2}n (Ln = Eu3+ and Nd3+) have been synthesised and structurally characterised. The photophysical properties for the Nd3+ complex presented relatively long lifetimes and high quantum yields in comparison with analogous ß-diketonate complexes. Mixed lanthanoid complexes were also formed and their luminescence properties studied, with effective sensitisation of the 4F3/2 of Nd3+via the 5D0 of Eu3+, which is to the best of our knowledge the first example of Eu3+ to Nd3+ sensitisation in a structurally defined coordination complex or polymer.

10.
J Org Chem ; 83(17): 9741-9755, 2018 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-30080044

RESUMO

A novel chiral disulfoxide ligand pair bearing fluorine atoms at the 6 and 6' position of its atropisomeric backbone, ( M, S, S)- and ( P, S, S)- p-Tol-6F-BIPHESO, was synthesized. Complexation to a rhodium(I) precursor gave rise to µ-Cl- and µ-OH-bridged rhodium dimer complexes incorporating the new ( M, S, S)- p-Tol-6F-BIPHESO ligand, while its sibling ( P, S, S)- p-Tol-6F-BIPHESO was not complexed efficiently to the rhodium precursor. The performance of this disulfoxide ligand [( M, S, S)- p-Tol-6F-BIPHESO] in catalysis was tested in both 1,4- and 1,2-addition reactions of arylboronic acids. We show that addition to both cyclic and acyclic enones as well as N-tosylarylimines proceeds with high yields and high enantioselectivities to give the corresponding products. The synthesis of enantiomerically pure p-Tol-6F-BIPHESO is straightforward and inexpensive which, together with the high catalytic performance and wide substrate scope for these addition reactions, makes it a very attractive alternative to more classical chiral ligand entities.

11.
J Nat Prod ; 81(7): 1658-1665, 2018 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-30020782

RESUMO

The identity of the natural product samoquasine A has remained obscure since its isolation from custard apple seeds in 2000. One of the proposed structures, benzo[ f]phthalazin-4(3 H)-one, was prepared in two steps by regioselective ortho-lithiation/formylation of N, N-diisopropyl-2-naphthylamide, followed by cyclization with hydrazine, but was shown to be different from the natural product. Perlolidine, another candidate structure, was synthesized by a novel route involving a ß-selective Heck reaction of butyl vinyl ether. Both perlolidine and samoquasine A are converted by trimethylsilyldiazomethane into the same N-methyl derivative. In addition, the 13C NMR spectra of perlolidine and another structurally mis-assigned natural product, cherimoline, are almost identical. Thus, both samoquasine A and cherimoline are actually perlolidine.


Assuntos
Annona/química , Quinazolinas/química , Produtos Biológicos/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Extratos Vegetais/química
12.
Dalton Trans ; 47(24): 7956-7964, 2018 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-29855648

RESUMO

An isomorphous series of lanthanoid complexes containing tribenzoylmethanide (tbm) and 1,10-phenanthroline (phen) ligands has been synthesised and structurally characterised. These complexes, formulated as [Ln(phen)(tbm)3] (Ln = Eu3+, Er3+ and Yb3+), were compared with analogous dibenzoylmethanide (dbm) [Ln(phen)(dbm)3] complexes to investigate the effect of changing ß-diketonate to ß-triketonate ligands on the photophysical properties of the complex. The photophysical properties for the Eu3+ complexes were similar for both systems, whereas a modest enhancement was observed for Yb3+ and Er3+ moving from the dbm to the tbm complexes. A detailed study of the NIR photophysical properties was achieved by adapting the integrating sphere method for the calculation of overall quantum yields in the solid state.

13.
Acta Crystallogr C Struct Chem ; 74(Pt 2): 152-158, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29400329

RESUMO

Guanidine is the functional group on the side chain of arginine, one of the fundamental building blocks of life. In recent years, a number of compounds based on the aminoguanidine (AG) moiety have been described as presenting high anticancer activities. The product of condensation between two molecules of AG and one molecule of formaldehyde was isolated in the protonated form as the dinitrate salt (systematic name: 2,8-diamino-1,3,4,6,7,9-hexaazanona-1,8-diene-1,9-diium dinitrate), C3H14N82+·2NO3-, (I). The cation lacks crystallographically imposed symmetry and comprises two terminal planar guanidinium groups, which share an N-C-N unit. Each cation in (I) builds 14 N-H...O hydrogen bonds and is separated from adjacent cations by seven nitrate anions. The AG self-condensation reaction in the presence of copper(II) chloride and chloride anions led to the formation of the organic-inorganic hybrid 1,2-bis(diaminomethylidene)hydrazine-1,2-diium tetrachloridocuprate(II), (C2H10N6)[CuCl4], (II). Its asymmetric unit is composed of half a diprotonated 1,2-bis(diaminomethylidene)hydrazine-1,2-diium dication and half a tetrachloridocuprate(II) dianion, with the CuII atom situated on a twofold rotation axis. The planar guanidinium fragments in (II) have their planes twisted by approximately 77.64 (5)° with respect to each other. The tetrahedral [CuCl4]2- anion is severely distorted and its pronounced `planarity' must originate from its involvement in multiple N-H...Cl hydrogen bonds. It was reported that [CuCl4]2- anions, with a trans-Cl-Cu-Cl angle (Θ) of ∼140°, are yellow-green at room temperature, with the colour shifting to a deeper green as Θ increases and toward orange as Θ decreases. Brown salt (II), with a Θ value of 142.059 (8)°, does not fit the trend, which emphasizes the need to take other structural factors into consideration. In the crystal of salt (II), layers of cations and anions alternate along the b axis, with the minimum Cu...Cu distance being 7.5408 (3) Šinside a layer. The structures of salts (I) and (II) were substantiated via spectroscopic data. The endothermic reaction involved in the thermal decomposition of (I) requires additional oxygen. The title salts may be useful for the screening of new substances with biological activity.

14.
Dalton Trans ; 46(33): 10899-10907, 2017 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-28766632

RESUMO

This paper describes the facile synthesis of a number of electron rich octamethyl[1.4]ferrocenophanes with unsaturated handles from 1,1'-bis(1-chlorovinyl)octamethylferrocene. Treatment of this reactive compound with sodium hydroxide in DMF initiates a series of reactions resulting in the formation of four different ferrocenophanes. The most complex of these products arises from a cascade of cyclisations giving an unusual, unsymmetrical bis-ferrocenophane with a central fused cyclobutene. Control over the reaction outcome is achieved by manipulating the concentration of NaOH. Mechanisms are proposed, and supported by DFT calculations.

15.
Chemistry ; 23(62): 15666-15679, 2017 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-28782852

RESUMO

A family of five neutral cyclometalated iridium(III) tetrazolato complexes and their methylated cationic analogues have been synthesised and characterised. The complexes are distinguished by variations of the substituents or degree of π conjugation on either the phenylpyridine or tetrazolato ligands. The photophysical properties of these species have been evaluated in organic and aqueous media, revealing predominantly a solvatochromic emission originating from mixed metal-to-ligand and ligand-to-ligand charge transfer excited states of triplet multiplicity. These emissions are characterised by typically long excited-state lifetimes (∼hundreds of ns), and quantum yields around 5-10 % in aqueous media. Methylation of the complexes caused a systematic red-shift of the emission profiles. The behaviour and the effects of the different complexes were then examined in cells. The neutral species localised mostly in the endoplasmic reticulum and lipid droplets, whereas the majority of the cationic complexes localised in the mitochondria. The amount of complexes found within cells does not depend on lipophilicity, which potentially suggests diverse uptake mechanisms. Methylated analogues were found to be more cytotoxic compared to the neutral species, a behaviour that might to be linked to a combination of uptake and intracellular localisation.


Assuntos
Complexos de Coordenação/química , Irídio/química , Tetrazóis/química , Animais , Cátions/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/metabolismo , Complexos de Coordenação/toxicidade , Cristalografia por Raios X , Retículo Endoplasmático/química , Retículo Endoplasmático/metabolismo , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Ligantes , Luz , Microscopia de Fluorescência , Conformação Molecular , Fotólise/efeitos da radiação , Piridinas/química , Ratos
16.
Inorg Chem ; 56(15): 8975-8985, 2017 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-28696105

RESUMO

The reaction of the ß-triketonate ligands tris(4-methylbenzoyl)methanide and tribenzoylmethanide with the trivalent lanthanoids Eu3+, Er3+, and Yb3+ in the presence of Cs+ afforded polymeric structures where the repeating units are represented by bimetallic tetranuclear assemblies of formulation {[Ln(Cs)(ß-triketonate)4]2}n. The only exception is the structure formed by the reaction of tris(4-methylbenzoyl)methanide, Yb3+, and Cs+, which yielded a polymeric assembly where the repeating units are mononuclear Yb3+ complexes bridged by Cs+ cations. Photophysical measurements on the obtained materials confirmed efficient sensitization from the ligand excited states to the 4f* excited states of the three lanthanoids. According to transient absorption data, Er3+ and Yb3+ are sensitized via energy transfer from the triplet state of the ß-triketonate ligands. On the other hand, energy transfer to Eu3+ seems to occur via an alternative pathway, possibly directly via the singlet state or through ligand to metal charge transfer states. The emission measurements confirm efficient sensitization for all three lanthanoids and bright near-infrared emission for Er3+ and Yb3+, a characteristic that seems to be linked to the specific chemical structure of the ß-triketonate ligands.

17.
Dalton Trans ; 46(24): 7844-7856, 2017 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-28594025

RESUMO

Gold(iii) N-heterocyclic carbene (NHC) complexes of form [Au(NHC)4Cl2]Cl were synthesized by reaction of KAuCl4 with bis- and tetrakis(imidazolium) salts in the presence of a mild base. Treatment of these complexes with KPF6 afforded four-coordinate AuIII complexes of form [Au(NHC)4](PF6)3. X-Ray crystallography showed the [AuIII(NHC)4]3+ cations in the hexafluorophosphate salts to have a square planar Au(NHC)4 moiety [AuCNHC 2.024(4)-2.082(7) Å]. In the [AuIII(NHC)4Cl2]+ cations in the chloride salts, coordination about Au was tetragonally-distorted octahedral, the axial Au-Cl bonds being substantially longer [AuCl 3.148(2)-3.693(1) Å] than the equatorial Au-CNHC bonds [AuC 2.024(4)-2.082(7) Å]. NMR and conductance studies suggested that the structures of the complexes seen in the solid state persisted in DMSO solution, except in one case where a chlorido ligand dissociated from [AuIII(NHC)4Cl2]+ to form [AuIII(NHC)4Cl]2+. The AuIII(NHC)4 unit was surprisingly robust. An AuIII complex was found to undergo H/D exchange reactions in D2O solution at 100 °C with no signs of decomposition detectable by 1H NMR spectroscopy. 1H NMR studies showed that various complexes containing AuIII(NHC)4 moieties underwent little or no decomposition when heated at 120 °C in DMSO-d6 for extended periods.

18.
Inorg Chem ; 56(12): 6999-7009, 2017 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-28556666

RESUMO

The reaction of Co(CH3COO)2·4H2O with the Schiff base ligand LH4 derived from o-vanillin and tris(hydroxymethyl)aminomethane produces the dinuclear mixed-valence complex [CoIICoIII(LH2)2(CH3COO)(H2O)](H2O)3 (1), which has been investigated using IR spectroscopy, X-ray crystallography, temperature-dependent magnetic susceptibility, magnetization, HFEPR spectroscopy, and ac susceptibility measurements at various frequencies, temperatures, and external magnetic fields. The structure of 1 consists of neutral molecules in which two cobalt ions with distorted octahedral geometries, CoIIO6 and CoIIIN2O4, are bridged by two deprotonated -CH2O- groups of the two LH22- ligands. 1 completes a series with Cl, Br, NO3, and NCS anions published before by different authors. Low-temperature HFEPR measurements reveal that the ground electronic state of the Co(II) center in 1 is a highly anisotropic Kramers doublet; the effective g values of 7.18, 2.97, and 1.96 are frequency-independent over the frequency ranges 200-630, 200-406, and 200-300 GHz for the highest, intermediate, and lowest geff values, respectively. The two lower values were not seen at higher frequencies because the magnetic field was not high enough. Temperature-dependent magnetic susceptibility and field-dependent magnetization data confirm high magnetic anisotropy of the easy axis type. Complex 1 behaves as a single-ion magnet under a small applied external field and demonstrates two relaxation modes that strongly depend on the applied static dc field. The observation of multiple relaxation pathways clearly distinguishes 1 from the Cl and Br analogues.

19.
Chemistry ; 23(27): 6518-6521, 2017 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-28337805

RESUMO

Rhenium and ruthenium complexes containing N-heterocylic carbene (NHC) ligands and conjugated to indomethacin were prepared. The anticancer properties were probed against pancreatic cell lines, revealing a remarkable activity of the rhenium fragment as anticancer agent. The ruthenium complexes were found to be inactive against the same pancreatic cancer cell lines, either alone or in conjugation with indomethacin. An in-depth biological study revealed the origin of the anticancer properties of the rhenium tricarbonyl fragment, of which a complete elucidation had yet to be achieved. It was found that the rhenium complexes induce cell cycle arrest at the G2/M phase by inhibiting the phosphorylation of Aurora-A kinase. A preliminary study on the structure-activity relationship on a large family of these complexes revealed that the anticancer properties are mainly associated with the lability of the ancillary ligand, with inert complexes showing limited to no anticancer properties.


Assuntos
Antineoplásicos/química , Aurora Quinase A/metabolismo , Complexos de Coordenação/química , Rutênio/química , Antineoplásicos/síntese química , Antineoplásicos/toxicidade , Aurora Quinase A/antagonistas & inibidores , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/toxicidade , Cristalografia por Raios X , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Células HEK293 , Humanos , Ligantes , Pontos de Checagem da Fase M do Ciclo Celular/efeitos dos fármacos , Metano/análogos & derivados , Metano/química , Conformação Molecular , Fosforilação/efeitos dos fármacos , Relação Estrutura-Atividade
20.
Dalton Trans ; 46(11): 3631-3641, 2017 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-28247876

RESUMO

Two new N-heterocyclic carbene (NHC) ligands bearing 2-morpholino and 2-piperidinyl naphthyl wingtips were synthesised (2-SIMorNap and 2-SIPipNap). Nuclear magnetic resonance studies, in conjunction with crystal structures and derivatisation of the NHC salts using a chiral counteranion, revealed that the ligand wingtips are oriented anti with respect to each other. From the free carbene, palladium, ruthenium and iridium complexes were prepared. NHC-iridium dicarbonyl complexes were made in order to extract the TEP values for these ligands. The study showed that these NHC ligands are more electron-donating than normal, aryl-substituted NHCs. The palladium complexes were tested in representative Suzuki-Miyaura cross-coupling reactions and compared to the state of the art systems. Ruthenium-catalysed ring-closing metathesis with these ligands was also performed. It was found that Grubbs' 2nd generation catalyst incorporating 2-SIPipNap did not initiate at room temperature and required heating for RCM to occur.

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