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1.
Inorg Chem ; 63(24): 11155-11167, 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38829561

RESUMEN

We report the synthesis and characterization of five novel Cd2+/UO22+ heterometallic complexes that feature Cd-oxo distances ranging from 78 to 171% of the sum of the van der Waals radii for these atoms. This work marks an extension of our previously reported Pb2+/UO22+ and Ag+/UO22+ complexes, yet with much more pronounced structural and spectroscopic effects resulting from Cd-oxo interactions. We observe a major shift in the U═O symmetric stretch and significant uranyl bond length asymmetry. The ρbcp values calculated using Quantum Theory of Atoms in Molecules (QTAIM) support the asymmetry displayed in the structural data and indicate a decrease in covalent character in U═O bonds with close Cd-oxo contacts, more so than in related compounds containing Pb2+ and Ag+. Second-order perturbation theory (SOPT) analysis reveals that O spx → Cd s is the most significant orbital overlap and U═O bonding and antibonding orbitals also contribute to the interaction (U═O σ/π → Cd d and Cd s → U═O σ/π*). The overall stabilization energies for these interactions were lower than those in previously reported Pb2+ cations, yet larger than related Ag+ compounds. Analysis of the equatorial coordination sphere of the Cd2+/UO22+ compounds (along with Pb2+/UO22+ complexes) reveals that 7-coordinate uranium favors closer, stronger Mn+-oxo contacts. These results indicate that U═O bond strength tuning is possible with judicious choice of metal cations for oxo interactions and equatorial ligand coordination.

2.
Inorg Chem ; 63(11): 4957-4971, 2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38437845

RESUMEN

Reported are the syntheses, structural characterizations, and luminescence properties of three novel [UO2Cl4]2- bearing compounds containing substituted 1,1'-dialkyl-4,4'-bipyridinum dications (i.e., viologens). These compounds undergo photoinduced luminescence quenching upon exposure to UV radiation. This reactivity is concurrent with two phenomena: radicalization of the uranyl tetrachloride anion and photoelectron transfer to the viologen which constitutes the formal transfer of one electron from [UO2Cl4]2- to the viologen species. This behavior is elucidated using electron paramagnetic resonance (EPR) spectroscopy and further probed through a series of characterization and computational techniques including Rehm-Weller analysis, time-dependent density functional theory (TD-DFT), and density of states (DOS). This work provides a systematic study of the photoreactivity of the uranyl unit in the solid state, an under-described aspect of fundamental uranyl chemistry.

3.
Inorg Chem ; 63(5): 2495-2504, 2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38266166

RESUMEN

Reported are the syntheses and characterization of five compounds containing one-dimensional uranyl fluoride chains charge balanced by 4-X-pyridinium (X = H, F, Cl, Br, I) cations. Structural analysis reveals molecular assembly via noncovalent interactions in the second coordination sphere with the X···Oyl interaction distances ranging from 2.987(7) to 3.142(3) Å, all of which are less than or close to the sum of the van der Waals radii. These interactions were probed via luminescence and Raman spectroscopy, where the latter indicates slight differences in the U═O symmetric stretches as a consequence of U═O in-phase and out-of-phase Raman-active stretches. The decrease in the X···Oyl sum of the van der Waals overlap between comparable compounds within the series manifests as a red-shifting trend among the Raman symmetric stretches. Computational density functional theory (DFT)-based frequency, electrostatic potential surfaces (ESPs), and natural bonding orbital (NBO) methods support the observed Raman spectroscopic features and provide a comprehensive rationale for assembly.

4.
Angew Chem Int Ed Engl ; 63(7): e202318161, 2024 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-38141052

RESUMEN

A series of compounds of the form [HAr]2 [UO2 X4 ] is reported here, wherein Ar is systematically varied between pyridine (1-X), quinoline (2-X), acridine (3-X), 2,5-dimethylpyrazine (4-X), quinoxaline (5-X), and phenazine (6-X), and X=Cl or Br. With greater conjugation in the organic cation, a larger quenching in uranyl luminescence is observed in the solid state. Supporting our luminescence experiments with computation, we map out the potential energy diagrams for the singlet and triplet states of both the [HAr]+ cations and [UO2 Cl4 ]2- anion in the crystalline state, and of the assembly. The distinct energy transfer pathways in each compound are discussed.

5.
Dalton Trans ; 52(47): 17656-17665, 2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-37943084

RESUMEN

Since their discovery in 1966, scorpionate ligands have been utilized to make coordination compounds for a variety of applications such as: studying organometallic reactions, biomimetic complexes, light-emitting materials and single-ion magnets. The recent development of a solvent-free pyrazole substitution chemistry has yielded the quantitative synthesis of asymmetrically functionalized all-pyrazole heteroscorpionate ligands. In this frontier article, we highlight the utility of all-pyrazole heteroscorpionates, specifically, nitro-trispyrazolylborates, in f-element chemistry. They offer great versatility in coordinating ability, donor strength, steric bulk and even optical charge transfer properties, all of which can be used to tune the properties of resultant complexes with metal ions. We show how they can impart structural diversity, sensitize Ln3+ luminescence and engender magnetic anisotropy and slow magnetic relaxation in the ion they coordinate. Additionally, we comment on the future of functionalized trispyrazolyl scorpionates, which includes enabling post-synthetic modifications of f-element complexes and becoming a platform to study the electronic properties of low oxidation state actinides.

6.
RSC Adv ; 13(20): 13477-13492, 2023 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-37152557

RESUMEN

Halide perovskites provide a versatile platform for exploring the effect of non-covalent interactions, including halogen bonding, on material properties such as band gap, luminescence, and frontier orbital landscape. Herein we report six new zero-dimensional tellurium iodide perovskite derivatives, consisting of [TeI6]2- octahedra charge balanced by one of several X-Py cations (X = H, Cl, Br, I, and Py = pyridinium). These compounds also feature robust halogen bonding between [TeI6]2- octahedra and polyiodides in the form of I2 (1-4), I3 - (5), or adjacent octahedra (4 and 6). These relatively strong non-covalent interactions (NCIs) are modeled by natural bond order (NBO) and second order perturbation theory (SOPT) calculations. NCIs are responsible for reducing the bandgap of these materials (measured via diffuse reflectance spectroscopy) relative to those without polyiodide species. They also affect inner sphere bonding in the metal halide, exacerbating [TeI6]2- octahedron asymmetry as compared to previously published compounds, with greater asymmetry correlating with higher van der Waals overlap of halogen-halogen contacts. We also demonstrate the ability of hydrogen and carbon bonding (which dominates in the absence of polyiodides) to affect inner sphere tellurium iodide bonding and octahedral symmetry.

7.
Dalton Trans ; 52(21): 7336-7351, 2023 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-37183775

RESUMEN

We report the synthesis, crystal structures, photophysical and magnetic properties of 11 novel lanthanide complexes with the asymmetrically functionalized trispyrazolylborate ligand 4-nitrotrispyrazolylborate, 4-NO2Tp-: [Ln(4-NO2Tp)3] (Ln = La-Dy, except Pm). In-depth photophysical characterization of the ligands via luminescence, reflectance and absorption spectroscopic techniques, decay lifetimes, quantum yields supported by time-dependent density functional theory (TD-DFT) and natural bond order (NBO) analysis reveal that n-NO2Tp- ligands are dominated by intra-ligand charge transfer (ILCT) transitions and that second-sphere interactions are critical to the stabilization of the T1 state of n-NO2Tp- ligands and hence their ability to sensitize Ln3+ emission. The luminescence properties of the complexes indicate that 4-NO2Tp- is a poor sensitizer of Ln3+ emission, unlike 3-NO2Tp-. Moreover, [Nd(4-NO2Tp)3] (crystallized as a hexane solvate) displays single-molecule magnet (SMM) properties, with longer relaxation times and larger barrier than the non-functionalized [NdTp3], attributed to the addition of the NO2-group and subsequent rigidification of the molecular structure.

8.
Inorg Chem ; 61(45): 17963-17971, 2022 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-36305869

RESUMEN

We report the synthesis of five new hybrid materials containing the [PuCl6]2- anion and charge-balancing, noncovalent interaction donating 4-X-pyridinium (X = H, Cl, Br, I) cations. Single crystals of the title compounds were grown and harvested from acidic, chloride-rich, aqueous media, and their structures were determined via X-ray diffraction. Compounds 1-4, (4XPyH)2[PuCl6], and 5, (4IPyH)4[PuCl6]·2Cl, exhibit two distinct sheet-like structure types. Structurally relevant noncovalent interactions were tabulated from crystallographic data and verified computationally using electrostatic surface potential maps and the quantum theory of atoms in molecules (QTAIM). The strength of the hydrogen and halogen bonds was quantified using Kohn-Sham density functional theory, and a hierarchy of acceptor-donor pairings was established. The PuIV-Cl bonds were studied using QTAIM and natural localized molecular orbital (NLMO) analyses to delineate the underlying bond mechanism and hybrid atomic orbital contributions therein. The results of the PuIV-Cl bond analyses were compared across compositions via analogous treatments of previously reported [PuO2Cl4]2- and [PuCl3(H2O)5] molecular units. The Pu-Cl bonds are predominately ionic yet exhibit small varying degrees of covalent character that increases from [PuCl3(H2O)5] and [PuO2Cl4]2- to [PuCl6]2-, while the participation of the Pu-based s/d and f orbitals concurrently decreases and increases, respectively.

9.
Dalton Trans ; 51(29): 11013-11020, 2022 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-35791868

RESUMEN

Herein we report on the synthesis of (HPyz+)2[UO2Cl3(H2O)(Pyz)0.5]2·2H2O which features a novel pyrazine-bridged uranyl dimer, [UO2Cl3(H2O)(Pyz)0.5]22-. A rigorous computational and experimental analysis of this compound was performed to fully explore the influence of coordination on the electronic structure and potential charge-transfer characteristics of this dimer, revealing a delocalized π-system across the bridging pyrazine and the axial components of both uranyl centers. Electrostatic surface potentials, used to rationalize the observed assembly, indicate a decreased basicity of the uranyl oxo versus [UO2Cl4]2-, and signify a lessened capacity for the terminal -yl oxos of the [UO2Cl3(H2O)(Pyz)0.5]22- dimer to participate in supramolecular assembly. A combined density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) analysis further evidenced an increase in UO bond strengths within the dimer, which is supported by a blue shift in the characteristic Raman-active uranyl symmetric stretch (ν1) with respect to the more typically observed [UO2Cl4]2-.

10.
Sci Total Environ ; 848: 157685, 2022 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-35908698

RESUMEN

The harmful effects of suspended sediment (SS) exposures on aquatic ecosystems have been well documented. Integrating this knowledge into the management plans of in-stream construction projects that cause SS releases remains challenging. Commonly, these projects have fixed scopes that require decisions about trade-offs between elevated SS concentrations (SSC, mg∙L-1) and duration of exposure (DoE, h). Constraining SSC to levels below a regulatory guideline may lead to an increase in project duration, while extended SS exposure times have uncertain environmental impacts and reduce project efficiency. This paper evaluates an alternative limit of SS dose (SSD, mg∙h∙L-1), which is defined herein as the product of SSC and DoE, as a more useful regulatory guideline compared to maximum SSC for fixed scope projects. Managing SSD may lead to improved outcomes for project efficiency without jeopardizing environmental health. A dose-response model for salmonids is developed to contrast this approach with more common regulatory limits applied to fixed scope projects that focus on managing SS releases using maximum SSC values within a given time interval. Results demonstrate that the latter constrain the management operating space to a subset of the acceptable range of exposures, which may reduce project efficiency and increase environmental risk. Based on simulated predictions for mean salmonid probabilities of major physiological and lethal effects, an SSD limit of 600 mg∙h∙L-1 may offer a conservative upper range of SSC and DoE values when managing salmonid populations, according to a common regulatory guideline for short-term exposures to not exceed 25 mg∙L-1 over 24 h. This SSD limit would increase the available operating space to enhance project efficiency by not overly constraining SSC. The methods developed in this study may be used to evaluate other SS management limits by undertaking Monte Carlo simulations using dose-response models fit to available datasets to assess acceptable operating ranges.


Asunto(s)
Sedimentos Geológicos , Ríos , Ecosistema
11.
Phys Chem Chem Phys ; 24(25): 15305-15320, 2022 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-35703012

RESUMEN

Reported is a series of eight antimony halide perovskite derivatives synthesized from acidic aqueous solutions of antimony oxide and halogen substituted pyridines. These materials feature anionic one-dimensional antimony halide (SbX; X = Cl, Br, I) chains or ribbons charge-balanced by organic para-halopyridinium cations (XPy; X = H, Cl, Br) which assemble into three-dimensional networks via halogen and hydrogen noncovalent interactions (NCIs) between ion pairs. Computational density functional theory (DFT) based natural bonding orbital (NBO) and density of state (DOS) methods were utilized to map the band structure and quantify and categorize noncovalent interaction strength and type. Moreover, we determined the presence of hybridized intermediate bands which are responsible for the small bandgap energies within this family and arise from mixing of the halide p-states and the Sb s-states. We note that the degree of hybridization, and thus optical properties, is influenced primarily by changes about inner sphere bonding and independent of second sphere interactions. This report is the first to specifically monitor the evolution of haloantimonate(III) hybrid perovskite atomic and molecular orbitals involved in optical behavior as a function of inner and outer sphere effects.

12.
Dalton Trans ; 51(26): 10095-10120, 2022 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-35731043

RESUMEN

Twelve novel Ag+/UO22+ heterometallic complexes have been prepared and characterized via structural, spectroscopic, and computational methods to probe the effects of Ag-oxo interactions on bonding and photophysical properties of the uranyl cation. Structural characterization reveals Ag-oxo interaction distances ranging from 2.475(3) Å to 4.287(4) Å. These interactions were probed using luminescence and Raman spectroscopy which displayed little effect on the luminescence intensity and the energy of the Raman active UO symmetric stretch peak as compared to previously reported Pb-oxo interactions. Computational efforts via density functional theory-based natural bond orbital analysis revealed that the highest stabilization energy associated with the Ag-oxo interaction had a value of only 11.03 kcal mol-1 and that all other energy values fell at 7.05 kcal mol-1 or below indicating weaker interactions relative to those previously reported for Pb2+/UO22+ heterometallic compounds. In contrast, quantum theory of atoms in molecules analysis of bond critical point electron density values indicated higher electron density in Ag-oxo interactions as compared to Pb-oxo interactions which suggests more covalent character with the Ag+. Overall, this data indicates that Ag+ has a less significant effect on UO22+ bonding and photophysical properties as compared to other Pb2+, likely due to the high polarizability of the cation.

13.
Sci Total Environ ; 807(Pt 1): 150844, 2022 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-34627878

RESUMEN

Many studies have investigated the consequences of exposure to fine-grained suspended sediments (SS) on aquatic organisms. Exposure has two components-concentration and duration-and can be expressed as dose, where we define suspended sediment dose (SSD: mg·h·L-1) as the product of suspended sediment concentration (SSC: mg·L-1) and duration of exposure (DoE: h). We evaluated these three measurement endpoints for managing SS effects on salmonids by assembling and analyzing all published SS dose-response observations. Despite a prevalence in SS management guidelines for using SSC as a primary endpoint to manage SS effects on salmonids, SSC was found to be less effective than SSD or DoE as a predictor variable for the available dose-response observations. We used data visualization to identify trends and distinct response categories that were then evaluated using a logistic regression model that accounts for nested observations by study. The model estimates the probability of moving from behavioural to major physiological and lethal responses in the available literature, as explained by one or more predictor variables, including ln(SSC), ln(DoE), ln(SSD), and life stage (adult versus juvenile). Akaike Information Criterion (AIC) and receiver operating characteristic (ROC) were used to compare model fit and classification performance, respectively, among alternative models. The best performing model as judged by AIC and ROC incorporated ln(SSD) as the predictor variable.


Asunto(s)
Sedimentos Geológicos , Salmonidae , Animales , Organismos Acuáticos
14.
Inorg Chem ; 60(22): 17186-17200, 2021 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-34727497

RESUMEN

Reported are the syntheses and characterization of six new heterometallic UO22+/Pb2+ compounds. These materials feature rare instances of M-oxo interactions, which influence the bonding properties of the uranyl cation. The spectroscopic effects of these interactions were measured using luminescence and Raman spectroscopy. Computational density functional theory-based natural bonding orbital and quantum theory of atoms in molecules methods indicate interactions arise predominantly through charge transfer between cationic units via the electron-donating uranyl O spx lone pair orbitals and electron-accepting Pb2+ p orbitals. The interaction strength varies as a function of Pb-oxo interaction distance and angle with energy values ranging from 0.47 kcal/mol in the longer contacts to 21.94 kcal/mol in the shorter contacts. Uranyl units with stronger interactions at the oxo display an asymmetric bond weakening and a loss of covalent character in the U═O bonds interacting closely with the Pb2+ ion. Luminescence quenching is observed in cases in which strong Pb-oxo interactions are present and is accompanied by red-shifting of the uranyl symmetric Raman stretch. Changes to inner sphere uranyl bonding manifest as a weakening of the U═O bond as a result of interaction with the Pb2+ ion. Comprehensive evaluation of the effects of metal ions on uranyl spectra supports modeling efforts probing uranyl bonding and may inform applications such as forensic signatures.

15.
Inorg Chem ; 60(20): 15724-15743, 2021 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-34605635

RESUMEN

Reported are the syntheses, crystal structures, and photophysical properties of 28, novel lanthanide compounds across five structural types, [Ln(3-NO2Tp)2(NO3)] (1-Ln, Ln = La-Tm, except Pm), [Bu4N][Ln(3-NO2Tp)(NO3)3] (2-Ln, Ln = Yb, Lu), [Eu(3-NO2Tp)2Cl(H2O)]·2iPrOH (3-Eu), [{Ln(3-NO2Tp)2}2(µ2-CO3)]·MeOH (4-Ln, Ln = La-Gd, except Pm), and [{Ln(3-NO2Tp)}4(µ2-OMe)6(µ4-O)] (5-Ln, Ln = Pr-Tb, except Pm) with the 3-nitrotrispyrazolylborate (3-NO2Tp-) ligand. The reaction of methanol or isopropanol solutions of LnX3 (X = Cl, NO3) with the tetrabutyl ammonium salt of the flexidentate 3-NO2Tp- ([Bu4N][3-NO2Tp]) yields Ln(3-NO2Tp)x complexes of various nuclearities as either monomers (1-Ln, 2-Ln, 3-Eu), dimers (4-Ln), or tetramers (5-Ln) owing to the efficient conversion of atmospheric CO2 to CO32- (dimers) or ligand controlled solvolysis of lanthanide ions (tetramers). 3-NO2Tp- is an efficient sensitizer for both the visible and near-IR (NIR) emissions of most of the lanthanide series, except thulium. Optical measurements, supported by density functional theory calculations, indicate that the dual visible and NIR Ln3+ emission arises from two intraligand charge transfer (ILCT) transitions of 3-NO2Tp-. This is the first report of lanthanide complexes with a nitro-functionalized pyrazolylborate ligand. The derivatization of the known Tp- ligand results in new coordination chemistry governed by the increased denticity of 3-NO2Tp-, imparting remarkable structural diversity and charge transfer properties to resultant lanthanide complexes.

16.
Dalton Trans ; 50(26): 9158-9172, 2021 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-34115090

RESUMEN

We report the synthesis and characterization of a family of UO22+/Co2+ isothiocyanate materials containing [UO2(NCS)5]3- and/or [Co(NCS)4]2- building units charged balanced by tetramethylammonium cations and assembled via SS or SOyl non-covalent interactions (NCIs), namely (C4H12N)3[UO2(NCS)5], (C4H12N)2[Co(NCS)4], and (C4H12N)5[Co(NCS)4][UO2(NCS)5]. The homometallic uranyl phase preferentially assembles via SS interactions, whereas in the heterometallic phase SOyl interactions are predominant. The variation in assembly mode is explored using electrostatic surfaces potentials, revealing that the pendant -NCS ligands of the [Co(NCS)4]2- anion is capable of outcompeting those of the [UO2(NCS)5]3- anion. Notably, the heterometallic phase displays atypical blue shifting of the uranyl symmetric stretch in the Raman spectra, which is in contrast to many other compounds featuring non-covalent interactions at uranyl oxygen atoms. A combined experimental and computational (density functional theory and natural bond orbital analyses) approach revealed that coupling of the uranyl symmetric stretch with isothiocyanate modes of equatorial -NCS ligands was responsible for the atypical blue shift in the heterometallic phase.

17.
Psychol Addict Behav ; 35(8): 895-900, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33507787

RESUMEN

OBJECTIVE: Franken's attentional bias hypothesis proposes that attentional bias to alcohol (ABA) activates craving, which motivates alcohol consumption behavior. While this hypothesis was put forward to account for alcohol dependence, the present study tested whether Franken's model may potentially contribute to explaining variation in beer consumption among young social drinkers. METHOD: ABA was measured by presenting participants with dual videos, one showing alcoholic beverages and the other non-alcoholic beverages, and assessing relative attention to each using a visual probe procedure. Self-reported alcohol craving was assessed four times over the session. In vivo alcoholic beverage consumption was assessed by the remaining weight of alcohol bottle following consumption, measured at conclusion of the experiment. RESULTS: The study revealed that ABA positively predicted alcohol craving (p < .01) and in vivo beer consumption (p < .01). The relationship between ABA and beer consumption was fully mediated by craving (ß = .63, 95% CI [.04, 1.29]). CONCLUSIONS: To our knowledge, this is the first study to show that the relationship between ABA and in vivo alcoholic beverage consumption is fully mediated by alcohol craving. Future research can extend understanding of the causal relationship between ABA, craving, and consumption, by determining whether direct modification of ABA influences alcohol consumption by altering craving. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Asunto(s)
Sesgo Atencional , Ansia , Consumo de Bebidas Alcohólicas , Bebidas Alcohólicas , Señales (Psicología) , Humanos
18.
Angew Chem Int Ed Engl ; 58(46): 16508-16511, 2019 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-31536176

RESUMEN

The synthesis, structure, and spectroscopic characterization of the first transplutonium metal-organic framework (MOF) is described. The preparation and structure of Am-GWMOF-6, [Am2 (C6 H8 O4 )3 (H2 O)2 ][(C10 H8 N2 )], is analogous to that of the isostructural trivalent lanthanide-only containing material GWMOF-6. The presented MOF architecture is used as a platform to probe Am3+ coordination chemistry and guest-enhanced luminescent emission, whereas the framework itself provides a means to monitor the effects of self-irradiation upon crystallinity over time. Presented here is a discussion of these properties and the opportunities that MOFs provide in the structural and spectroscopic study of actinides.

19.
Chemistry ; 25(29): 7114-7118, 2019 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-30970154

RESUMEN

A new thorium metal-organic framework (MOF), Th(OBA)2 , where OBA is 4,4'-oxybis(benzoic) acid, has been synthesized hydrothermally in the presence of a range of nitrogen-donor coordination modulators. This Th-MOF, described herein as GWMOF-13, has been characterized by single-crystal and powder X-ray diffraction, as well as through a range of techniques including gas sorption, thermogravimetric analysis (TGA), solid-state UV/Vis and luminescence spectroscopy. Single-crystal X-ray diffraction analysis of GWMOF-13 reveals an interesting, high symmetry (cubic Ia 3 ‾ d) structure, which yields a novel srs-a topology. Most notably, TGA analysis of GWMOF-13 reveals framework stability to 525 °C, matching the thermal stability benchmarks of the UiO-66 series MOFs and zeolitic imidazolate frameworks (ZIFs), and setting a new standard for thermal stability in f-block based MOFs.

20.
Inorg Chem ; 58(11): 7243-7254, 2019 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-30998003

RESUMEN

Six new uranyl hybrid materials have been synthesized solvothermally utilizing the ligands 2,2'-bipyridine-3,3'-dicarboxylic acid (H2L) and 2,2':6',2''-terpyridine (TPY). The six compounds are classified as either molecular complexes (I0O0 connectivity), [(UO2)(L)(TPY)]·H2O (1), [Ni(TPY)2][(UO2)(L)2]·3H2O (2), and [Cu(TPY)2][(UO2)(L)2]·3H2O (3), or 3D metal-organic frameworks (MOFs, I0O3 connectivity), [Cu2(UO2)2(OH)(C2H3O2)(L)3(TPY)2]·6H2O (4), [Zn2(UO2)2(OH)(NO3)(C2H3O2)(L)3(TPY)2]·4H2O (5), and Na[Ni(UO2)3(OH)(O)(L)3]·9H2O (6). A discussion of the influence of transition metal incorporation, chelating effects of the ligand, and synthesis conditions on the formation of uranyl materials is presented. The structure of compound 6 is of particular note due to large channel-like voids with a diameter of approximately 19.6 Å. A topological analysis of 6 reveals a new topology with a 9-nodal 3,3,3,3,3,3,3,4,5-connected network, designated geg1 hereafter. Further, solid state photoluminescence experiments show emission and lifetimes values consistent with related uranyl compounds.

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