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1.
Inorg Chem ; 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32909432

RESUMO

In the field of stimuli-responsive luminescent materials, mechanochromic compounds exhibiting reversible emission color changes activated by mechanical stimulation present appealing perspectives in sensor applications. The mechanochromic luminescence properties of the molecular cubane copper iodide cluster [Cu4I4[PPh2(C6H4-CH2OH)]4] (1) are reported in this study. This compound can form upon melting an amorphous phase, giving an unprecedented opportunity to investigate the mechanochromism phenomenon. Because the mechanically induced crystalline-to-amorphous transition is only partial, the completely amorphous phase represents the ultimate state of the mechanically altered phase. Furthermore, the studied compound could form two different crystalline polymorphs, namely, [Cu4I4[PPh2(C6H4-CH2OH)]4]·C2H3N (1·CH3CN) and [Cu4I4[PPh2(C6H4-CH2OH)]4]·3C4H8O (1·THF), allowing the establishment of straightforward structure-property relationships. Photophysical and structural characterizations of 1 in different states were performed, and the experimental data were supported by theoretical investigations. Solid-state NMR analysis permitted quantification of the amorphous part in the mechanically altered phase. IR and Raman analysis enabled identification of the spectroscopic signatures of each state. Density functional theory calculations led to assignment of both the NMR characteristics and the vibrational bands. Rationalization of the photoluminescence properties was also conducted, with simulation of the phosphorescence spectra allowing an accurate interpretation of the thermochromic luminescence properties of this family of compounds. The combined study of crystalline polymorphism and the amorphous state allowed us to get deeper into the mechanochromism mechanism that implies changes of the [Cu4I4] cluster core geometry. Through the combination of multistimuli-responsive properties, copper iodide clusters constitute an appealing class of compounds toward original functional materials.

2.
Dalton Trans ; 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32807997

RESUMO

The tridentate ligand 1,8-bis-(2,6-diisopropylphenyl)imino-3,6-di-tert-butyl-carbazolate, {CarbDiPP}-, has been used to prepare a variety of complexes of the large alkaline earths (Ae) calcium, strontium and barium. A complex of their smaller congener, magnesium, has also been synthesised. The range of coligands that have been utilised include alkyls, amides, halides and tetrelides. All structurally characterised complexes presented herein are stable in solution and do not undergo ligand redistribution that is otherwise well-known to pollute the chemistry of the alkaline-earth metals. Detailed structural and spectroscopic data for these compounds are discussed. They provide compelling evidence that this nitrogen ligand allows for the kinetic stabilisation of Ae complexes through optimal steric encapsulation of the voluminous metal centres. Its ease of access combined to its evident versatility make {CarbDiPP}H stand out in the portfolio of proligands that have been devised for similar purposes in the past decade. Yet, it fell short in our attempts to synthesise heteroleptic Ae-hydrides upon action of PhSiH3 onto Ae-amides, as the crystallised products showed the imine groups were prone to hydride reduction and formal hydrosilylation.

3.
Org Lett ; 22(15): 5936-5940, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32643948

RESUMO

We report herein P(III)-directed C-H bond alkenylation of (dialkyl)- and (diaryl)biarylphosphines using internal alkynes. Chloride-free [Rh(OAc)(COD)]2 acts as a better catalyst than commercially available [RhCl(COD)]2. Conditions were developed to control the mono- and difunctionalization depending on the alkyne stoichiometry. One of these novel bisalkenylated (dialkyl)biarylphosphines was employed for the preparation of a palladium(II) complex, and some of these functionalized ligands outperformed their corresponding unfunctionalized phosphines in Pd-catalyzed amidation with sterically hindered aryl chlorides.

4.
Chemistry ; 2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32463553

RESUMO

We report on the synthesis and characterization of three iron(III) phosphasalen complexes, [Fe III (Psalen)(X)] differing in the nature of the counter-anion/exogenous ligand (X - = Cl - , NO 3 - , OTf - ), as well as the neutral iron(II) analogue, [Fe II (Psalen)] . Phosphasalen (Psalen) differs from salen by the presence of iminophosphorane (P=N) functions in place of the imines. All the complexes were characterized by single-crystal X-ray diffraction, UV-vis, EPR, and cyclic voltammetry. The [Fe II (Psalen)] complex was shown to remain tetracoordinated even in coordinating solvent but exhibits surprisingly a magnetic moment in line with a Fe II high spin ground state. For the Fe III complexes, the higher lability of triflate anion compared to nitrate was demonstrated. As they exhibit lower reduction potentials compared to their salen analogues, these complexes were tested for the coupling of 2-naphtol using O 2 from air as oxidant. In order to shed light on this reaction, the interaction between 2-napthol and the Fe III (Psalen) complexes was studied by cyclic voltammetry as well as UV-vis spectrosocopy.

5.
Inorg Chem ; 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32233459

RESUMO

The photoluminescent stimuli-responsive properties of two crystalline polymorphs with the formula (PPh4)2[Cu2I4] are reported. Distinct luminescence properties are exhibited by these ionic copper iodide compounds with blue or yellow emission, and original luminescence thermochromism and mechanochromism are demonstrated. While one polymorph displays contrasted temperature-dependent emission properties, the other shows great modification of its emission upon mechanical solicitation. The establishment of structure-properties relationships, supported by a theoretical approach, permits us to get insights into the origin of the photoluminescence properties and the mechanisms at play. According to DFT calculations, the different emission bands originate either from the (PPh4)+ organic cation or from the [Cu2I4]2- anion. Activation of these two emissive centers appears to be dependent on the crystalline packing of the polymorph. The thermochromism displayed by one polymorph can be attributed to a variation in temperature of the relative intensities of two emission bands of two different excited states. The origin is different for the other polymorph, with emission bands coming from two independent emissive centers: namely, (PPh4)+ and [Cu2I4]2-. The luminescence mechanochromism is attributed to a polymorphic transition. The mechanical solicitation induces a partial transformation of one polymorph into the other within a disordered phase. The mechanochromic mechanism can be related to mechanical modifications of intermolecular interactions between the (PPh4)+ cations. By displaying luminescence properties that depend on crystalline structure, excitation wavelength, temperature, and mechanical solicitation, the studied copper iodides offer a great possibility of emissive color control and switching, a clear demonstration of the great potentialities of this family of compounds for the development of photoactive materials.

6.
Artigo em Inglês | MEDLINE | ID: mdl-32091662

RESUMO

Reported here is a readily available bis(imino)carbazole-based proligand that constitutes a convenient entry point into the challenging synthetic molecular chemistry of barium. It enables the preparation of rare or even, up to now, unknown, solution-stable heteroleptic barium complexes. The syntheses and structural features for the first molecular barium fluoride and the first barium stannylide, with an unsupported Ba-Sn bond, are described, along with other carbazolate barium species: an amide (both a remarkably stable starting material and an excellent hydrophosphination precatalyst), iodide, and silanylide. DFT analysis of bonding patterns in the barium stannylide and barium silanylide highlights a prevailingly ionic barium-tetrelide bond with a small covalent contribution.

7.
Chem Commun (Camb) ; 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32104794

RESUMO

Two 1,1,4,4-tetracyanobutadiene (TCBD) derivatives were prepared by [2+2]cycloaddition-retroelectrocyclization from ynamides bearing either a pyrene (1) or a perylene unit (2). In addition to panchromatic absorptions in 2, in the solid state, both compounds unexpectedly display NIR photoluminescence that could be detected up to about 1350 nm.

8.
Inorg Chem ; 59(3): 1917-1927, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31934757

RESUMO

Irradiation of [Re2(CO)10] in the presence of BH3·thf resulted in the formation of several rhenium diborane(6) species, for example, [{(OC)4Re}{Re(CO)3}2(µ3-η2:η2:η2-B2H6)(µ-H)], 1; [{(OC)4Re}2{Re(CO)3}(µ3-η2:η2:η1-B2H6)(µ-H)], 2; and [{(OC)4Re}2(µ-η2:η2-B2H6)], 3, comprising diverse coordination modes of the [B2H6]2- ligand. Compound 1 contains a tris(bidentate) [B2H6]2- unit, whereas 2 consists of an unsymmetrically bound [µ3-η2:η2:η1-B2H6]2- ligand. In contrast, the irradiation of [Mn2(CO)10] with BH3·thf yielded only the Mn analogue of 1, [{(OC)4Mn}{Mn(CO)3}2(µ3-η2:η2:η2-B2H6)(µ-H)], 1'. In an attempt to generate the bimetallic Mn-diborane(6), we have carried out the reaction of 1' with PCy3 under photolytic conditions. The reaction led to the formation of two single base stabilized unsymmetrical diborane(5) species, [{Mn(CO)3}{Mn(CO)2PCy3}(µ-η2:η2-B2H5·PCy3)(µ-H)], 4, and [{Mn(CO)2PCy3}(η3-B2H5·PCy3)], 5. As [B2H6]2- and [B2H5·PCy3]- are isoelectronic, the bondings in 4 and 5 are analogous to that of diborane(6) species 1-3. All the new species have been characterized spectroscopically, and their structures were further confirmed by single-crystal X-ray diffraction studies. DFT-type quantum chemical calculations were carried out that provided insight into the bonding interaction of [B2H6]2- and [B2H5·PCy3]- with the M(CO)n fragments.

9.
J Med Genet ; 57(5): 301-307, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-30287593

RESUMO

BACKGROUND: The clinical significance of 16p13.11 duplications remains controversial while frequently detected in patients with developmental delay (DD), intellectual deficiency (ID) or autism spectrum disorder (ASD). Previously reported patients were not or poorly characterised. The absence of consensual recommendations leads to interpretation discrepancy and makes genetic counselling challenging. This study aims to decipher the genotype-phenotype correlations to improve genetic counselling and patients' medical care. METHODS: We retrospectively analysed data from 16 013 patients referred to 12 genetic centers for DD, ID or ASD, and who had a chromosomal microarray analysis. The referring geneticists of patients for whom a 16p13.11 duplication was detected were asked to complete a questionnaire for detailed clinical and genetic data for the patients and their parents. RESULTS: Clinical features are mainly speech delay and learning disabilities followed by ASD. A significant risk of cardiovascular disease was noted. About 90% of the patients inherited the duplication from a parent. At least one out of four parents carrying the duplication displayed a similar phenotype to the propositus. Genotype-phenotype correlations show no impact of the size of the duplicated segment on the severity of the phenotype. However, NDE1 and miR-484 seem to have an essential role in the neurocognitive phenotype. CONCLUSION: Our study shows that 16p13.11 microduplications are likely pathogenic when detected in the context of DD/ID/ASD and supports an essential role of NDE1 and miR-484 in the neurocognitive phenotype. Moreover, it suggests the need for cardiac evaluation and follow-up and a large study to evaluate the aortic disease risk.

10.
Am J Med Genet A ; 182(3): 446-453, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31876365

RESUMO

Kabuki syndrome (KS, KS1: OMIM 147920 and KS2: OMIM 300867) is caused by pathogenic variations in KMT2D or KDM6A. KS is characterized by multiple congenital anomalies and neurodevelopmental disorders. Growth restriction is frequently reported. Here we aimed to create specific growth charts for individuals with KS1, identify parameters used for size prognosis and investigate the impact of growth hormone therapy on adult height. Growth parameters and parental size were obtained for 95 KS1 individuals (41 females). Growth charts for height, weight, body mass index (BMI) and occipitofrontal circumference were generated in standard deviation values for the first time in KS1. Statural growth of KS1 individuals was compared to parental target size. According to the charts, height, weight, BMI, and occipitofrontal circumference were lower for KS1 individuals than the normative French population. For males and females, the mean growth of KS1 individuals was -2 and -1.8 SD of their parental target size, respectively. Growth hormone therapy did not increase size beyond the predicted size. This study, from the largest cohort available, proposes growth charts for widespread use in the management of KS1, especially for size prognosis and screening of other diseases responsible for growth impairment beyond a calculated specific target size.

11.
Chemistry ; 25(63): 14441-14446, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31478579

RESUMO

Herein, a direct C8-arylation reaction of 1-amidonaphthalenes is described. By using diaryliodonium salts as arylating agents, the palladium-catalyzed C-H activation reaction showed perfect C8 regioselectivity and a wide functional group tolerance. In most cases, the desired polyaromatic compounds were isolated in good to excellent yields. To explain the observed regioselectivity, DFT calculations were performed and highlighted the crucial role of the amide directing group. Finally, the utility of this method is showcased by the synthesis of benzanthrone derivatives.

13.
Inorganics (Basel) ; 7(5): 58, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31463301

RESUMO

This article presented the synthesis and characterization of original heterobimetallic species combining a divalent lanthanide fragment and a divalent nickel center bridged by the bipyrimidine ligand, a redox-active ligand. X-ray crystal structures were obtained for the Ni monomer (bipym)NiMe2, 1, as well as the heterobimetallic dimer compounds, Cp*2Yb(bipym)NiMe2, 2, along with 1H solution NMR, solid-state magnetic data, and DFT calculations only for 1. The reactivity with CO was investigated on both compounds and the stoichiometric acetone formation is discussed based on kinetic and mechanistic studies. The key role of the lanthanide fragment was demonstrated by the relatively slow CO migratory insertion step, which indicated the stability of the intermediate.

14.
Chem Sq ; 3: 1, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31463472

RESUMO

This article relates the synthesis and characterization of novel heterobimetallic complexes containing a low-valent lanthanide, a tetradentate redox non-innocent ligand, viz. the 4,5,9,10-tetraazaphenanthrene, taphen ligand and transition metal fragments of PdMe2 and PtMe2. The experimental results are supported by a theoretical study. Investigation of their reduction properties allowed the formation of isostructural original heterotrimetallic complexes containing two Cp*2Yb fragments and the (taphen)MMe2 (M = Pd and Pt) motifs. These complexes are stable in non-coordinating solvent such as toluene but decompose in coordinating solvents such as thf. Investigation of the internal electron transfer shows that the taphen ligand behaves as a two-electrons reservoir but is capable of transferring back only one electron in thf. This reversible electron(s) transfer is rare in organolanthanide chemistry and show the potential interest of these complexes in reductive chemistry. Additionally, the trinuclear complexes feature odd X-ray crystal structures in which a deviation of symmetry is observed. The latter observation was studied in depth using quantum chemistry calculations highlighting the role of non-covalent weak interactions.

15.
Chemistry ; 25(36): 8643-8648, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31033060

RESUMO

A one-pot methodology to synthesize metastable bicyclic 2,5-dihydrooxepines from cyclic 1,3-diketones and 1,4-dibromo-2-butenes through the retro-Claisen rearrangement of syn-2-vinylcyclopropyl diketone intermediates is reported. DFT calculations were performed to understand the reaction selectivity and mechanisms towards [1,3]- or [3,3]-sigmatropic rearrangements, highlighting the crucial influence of the temperature. The reaction was successfully applied to a short protecting group-free total synthesis of radulanin A, a natural 2,5-dihydrobenzoxepine. Moreover, the strong herbicidal potential of this natural product is demonstrated for the first time.

16.
J Med Genet ; 56(8): 526-535, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30923172

RESUMO

BACKGROUND: Balanced chromosomal rearrangements associated with abnormal phenotype are rare events, but may be challenging for genetic counselling, since molecular characterisation of breakpoints is not performed routinely. We used next-generation sequencing to characterise breakpoints of balanced chromosomal rearrangements at the molecular level in patients with intellectual disability and/or congenital anomalies. METHODS: Breakpoints were characterised by a paired-end low depth whole genome sequencing (WGS) strategy and validated by Sanger sequencing. Expression study of disrupted and neighbouring genes was performed by RT-qPCR from blood or lymphoblastoid cell line RNA. RESULTS: Among the 55 patients included (41 reciprocal translocations, 4 inversions, 2 insertions and 8 complex chromosomal rearrangements), we were able to detect 89% of chromosomal rearrangements (49/55). Molecular signatures at the breakpoints suggested that DNA breaks arose randomly and that there was no major influence of repeated elements. Non-homologous end-joining appeared as the main mechanism of repair (55% of rearrangements). A diagnosis could be established in 22/49 patients (44.8%), 15 by gene disruption (KANSL1, FOXP1, SPRED1, TLK2, MBD5, DMD, AUTS2, MEIS2, MEF2C, NRXN1, NFIX, SYNGAP1, GHR, ZMIZ1) and 7 by position effect (DLX5, MEF2C, BCL11B, SATB2, ZMIZ1). In addition, 16 new candidate genes were identified. Systematic gene expression studies further supported these results. We also showed the contribution of topologically associated domain maps to WGS data interpretation. CONCLUSION: Paired-end WGS is a valid strategy and may be used for structural variation characterisation in a clinical setting.

17.
Inorg Chem ; 58(4): 2872-2880, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30726073

RESUMO

The tailoring of the coordination chemistry around f-element centers is a crucial step for the development of compounds with slow magnetic relaxation, including single-molecule magnets (SMMs), which have great potential in molecular spintronics and for future quantum computing devices. Lanthanide ions are particularly interesting because the predominant electrostatic model of their bonding allows rationalizing their coordination symmetry. However, to the best of our knowledge, the redox properties of the lanthanides are not taken into account for the design of SMMs, and therefore all SMMs reported to date contain lanthanide ions in their trivalent oxidation state. In this Article, divalent lanthanide compounds presenting field-induced slow magnetic relaxation are reported. The rational design and synthesis of two TmII complexes with the 18-crown-6 ligand are presented along with their emission and EPR properties, which help to probe the desired nature of the ground state, that is, maximizing the anisotropy. The observed magnetic properties demonstrate their slow magnetic relaxation behavior in a moderate external magnetic field.

18.
Eur J Hum Genet ; 27(5): 701-710, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30710147

RESUMO

Exome sequencing (ES) has revolutionized diagnostic procedures in medical genetics, particularly for developmental diseases. The variety and complexity of the information produced has raised issues regarding its use in a clinical setting. Of particular interest are patients' expectations regarding the information disclosed, the accompaniment provided, and the value patients place on these. To explore these issues in parents of children with developmental disorders and no diagnosis with known etiology, a multidisciplinary group of researchers from social and behavioral sciences and patient organizations conducted a mixed-methodology study (quantitative and qualitative) in two centers of expertise for rare diseases in France. The quantitative study aimed to determine the preferences of 513 parents regarding the disclosure of ES results. It showed that parents wished to have exhaustive information, including variants of unknown significance possibly linked to their child's disorder and secondary findings. This desire for information could be a strategy to maximize the chances of obtaining a diagnosis. The qualitative study aimed to understand the expectations and reactions of 57 parents interviewed just after the return of ES results. In-depth analysis showed that parents had ambivalent feelings about the findings whatever the results returned. The contrasting results from these studies raise questions about the value of the information provided and parents' high expectations regarding the results. The nature of parental expectations has emerged as an important topic in efforts to optimize accompaniment and support for families during the informed decision-making process and after disclosure of the results in an overall context of uncertainty.

19.
J Am Chem Soc ; 140(43): 14433-14439, 2018 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-30296372

RESUMO

The Article presents the synthesis, structure, and bonding of a series of neutral and linear sandwich compounds with the cyclononatetraenyl (Cnt) ligand and divalent lanthanides. These compounds account for the emergence of the lanthanidocene series in reference to the ferrocene and uranocene. The synthetic strategy uses the solubility difference between two conformational isomers of the ligand, as well as the isomerization of the compounds induced by solvent coordination, yielding the isomorphous and isostructural neutral and rigorously linear sandwich complexes. The molecular structures feature a Cnt-Ln-Cnt angle of 180° and a ring size close to the Cnt-Cnt(centroid) distance. A qualitative molecular orbital diagram is provided, in D9 d symmetry, and DFT calculations enforce the bonding model.

20.
Chemistry ; 24(71): 18868-18872, 2018 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-30259587

RESUMO

A copper iodide complex coordinated by three phosphine ligands with the formula [Cu2 I2 (Ph2 PC2 (C6 H4 )C2 PPh2 )3 ] exhibits solvatochromic and vapochromic luminescence properties. A mechanism based on solvent-dependent molecular motion appears to occur. The highly contrasted response observed upon THF solvent exposure makes this complex an appealing candidate for chemical sensor applications.

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