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Dalton transactions
Royal Society of Chemistry
Dalton transactions

Royal Society of Chemistry

1477-9226

Dalton transactions/Journal Dalton transactionsEIAHCICCRISTPSCI
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    11页
      原文链接:
    • NSTL

    Recent developments on the transformation of CO2 utilising ligand cooperation and related strategies

    Ayyappan RamarajAbdalghani IssamDa Costa Rosenildo C.Owen Gareth R....
    30页
    查看更多>>摘要：A portfolio of value-added chemicals, fuels and building block compounds can be envisioned from CO2 on an industrial scale. The high kinetic and thermodynamic stabilities of CO2, however, present a significant barrier to its utilisation as a C1 source. In this context, metal–ligand cooperation methodologies have emerged as one of the most dominant strategies for the transformation of the CO2 molecule over the last decade or so. This review focuses on the advancements in CO2 transformation using these cooperative methodologies. Different and well-studied ligand cooperation methodologies, such as dearomatisation–aromatisation type cooperation, bimetallic cooperation (M?M′; M′ = main group or transition metal) and other related strategies are also discussed. Furthermore, the cooperative bond activations are subdivided based on the number of atoms connecting the reactive centre in the ligand framework (spacer/linker length) and the transition metal. Several similarities across these seemingly distinct cooperative methodologies are emphasised. Finally, this review brings out the challenges ahead in developing catalytic systems from these CO2 transformations.
      原文链接:
    • NSTL
    • Royal Soc Chemistry

    Synthesis of a Zr4(embonate)6–cobalt based superstructure for photocatalytic hydrogen production

    Teng QianHe Yan-PingChen Shu-MeiZhang Jian...
    5页
    查看更多>>摘要：Herein, we report an efficient method to construct cage-based MOF materials with exposed metal active sites for catalysis. By employing Zr4L6 (L = embonate) cages as precursors for assembly with N-containing ligands and Co2+ ions, a new Zr4L6–Co based chain structure (PTC-318) has been generated through two-step reactions. Interestingly, in the absence of a photosensitizer, PTC-318 exhibits notable photocatalytic activity for H2 evolution under visible-light irradiation.
      原文链接:
    • NSTL
    • Royal Soc Chemistry

    Heterolytic carbon–iodine bond cleavage by a palladium(i) metalloradical

    Sinclair Matthew J. G.Chaplin Adrian B.
    3页
    查看更多>>摘要：The well-defined Pd(i) metalloradical [Pd(PtBu3)2]+ reacts with aryl and alkyl iodides at room temperature, yielding [Pd(PtBu3)(μ-I)]2 and phosphonium salts. Pd(ii) aryl/alkyl derivates, reflecting net radical oxidative addition of the substrate to the metalloradical, are generated during the reaction and two examples have been isolated and crystallographically characterised.
      原文链接:
    • NSTL
    • Royal Soc Chemistry

    C(sp3)–H oxidation and chlorination catalysed by a bioinspired pincer iron(iii) complex

    Tan LimingWan YanjunLi GangAnderson Stephen N....
    5页
    查看更多>>摘要：A pincer iron(iii) catalyst for the oxidation and chlorination of C(sp3)–H bonds was developed. Oxidation of a diagnostic substrate cis-decalin implies that a long-lived carbon-centred radical is involved. Mechanistic studies suggest that an Fe-oxo species could be responsible for the rate-determining C–H activation step. This report expands the scope of non-heme catalysts for C–H functionalisation.
      原文链接:
    • NSTL
    • Royal Soc Chemistry

    Efficient neutron radiation shielding by boron–lithium imidazolate frameworks

    Li ZhenyuHan YueWang AosongZhao Dong...
    5页
    查看更多>>摘要：Radiation protective materials are widely applied to avoid occupational hazards from either particle emissions or high-energy electromagnetic waves. Herein, we present a boron imidazolate framework (BIF) as a novel neutron shielding additive with high neutron capture cross-section elements B/Li and H. The BIF1-based epoxy resin matrix (Ep-BIF1) possesses high thermal stability and excellent resistance capacity. The neutron radiation shielding property was characterized using an Am–Be source, in which the thermal neutron shielding efficiency of Ep-BIF1 is notably higher than that of Ep-B4C with equal boron concentration, showing potential applications as an advanced efficient neutron radiation shielding composite.
      原文链接:
    • NSTL
    • Royal Soc Chemistry

    Poly(allylamine)-copper(ii) coordination complex grafted on core@shell upconversion nanoparticles for ultrafast and sensitive determination of the phytohormone salicylic acid in plant extracts

    Carre?o-Vega OsvaldoVargas-Zamarripa MarleneSalas PedroRamírez-García Gonzalo...
    11页
    查看更多>>摘要：Salicylic acid (SA) is a phenolic phytohormone with critical roles in plant growth regulation and resistance to biotic and abiotic stress. Since low SA concentrations can modulate many plant biochemical responses, innovative analytical tools are required to deeply understand its activity and to control its exogenous application in modern agricultural systems. Herein, a NIR-activated composite based on NaYF4:Yb,Er@NaYF4 core@shell upconversion nanoparticles decorated with the poly(allylamine)-Cu(ii) complex [UCNPs-PAAm-Cu(ii)] was developed to sensitively determine the SA molecule in plant-derived samples. Accordingly, the PAAm-Cu(ii) complex grafted on the UCNPs induces a strategic charge transfer band which triggers a quenching process through a resonance energy transfer (RET) mechanism. Such process is gradually deactivated upon the addition of SA and the consequent formation of the SA-Cu(ii) complex, allowing a luminescence recovery in the 1–800 nM linear range. This mechanism is promoted by the strong stability of the SA-Cu(ii) complex (log?β2-SA/Cu = 19.01) which is over twelve orders of magnitude stronger than the PAAm-Cu2+ counterpart. Furthermore, the equilibrium and kinetic studies on the involved mononuclear Cu2+ complexes formation permitted instantaneous analytical responses and excellent selectivity against other representative phytohormones and metallic cations. The reliability of this method was demonstrated by determining the SA content of some edible fruits and vegetables comprising apple, lemon, kiwi, tomato, and cucumber, whose concentrations ranged from 0.30 to 2.99 μg g?1, with percent recoveries between 94.6 to 102.3%. Thereby, the reported nanocomplex can help to understand the SA activity in plants with significant applications in crop yield improvement and food quality assessment.
      原文链接:
    • NSTL
    • Royal Soc Chemistry

    Effect of the substituent on C–H activation catalyzed by a non-heme Fe(iv)O complex: a computational investigation of reactivity and hydrogen tunneling

    Katoch AkankshaMandal Debasish
    9页
    查看更多>>摘要：Density functional theory investigations were performed to address the C–H activation reactivity and the influence of quantum mechanical tunneling catalyzed by a non-heme iron(iv)-oxo complex, namely [FeIVOdpaq-X]+, where the macrocyclic ligand dpaq represents {2-[bis(pyridine-2-yl-methyl)]amino-N-quinolin-8-yl-acetamido}. Counter ion and solvent corrections were incorporated in the computation to avoid self-interaction error. To find the impact of the indirectly linked substituents to the central metal atom, Fe, the macrocyclic ligand dpaq was substituted at the 5-position of its quinoline moiety represented as dpaq-X and the reactivity and hydrogen tunneling were compared with the parent ligand dpaq-H. Here, both electron-donating, e.g. –N(CH3)2 and –OMe, and electron-withdrawing, e.g. –NO2 and –SO2CF3, substituents compared to hydrogen were considered. The reactions displayed exchange interaction favouring two-state reactivity (TSR) as the S = 2 state was found for the excited state in the reactant, which crossed the S = 1 path (initially the ground state) during the progress of the reaction. This was further verified by the tunneling corrected kinetic isotope effect (KIE), which closely matched with the experiment (32) in the S = 2 state (22), whereas the S = 1 KIE (～69) was found to be very far from that experimentally observed. More than 90% of all the C–H activation reactions proceeded through quantum mechanical tunneling even at room temperature. As the substituent group became more electron-donating, both the tunneling contributions and the kinetic isotope effect increased, which supported the anti-electrophilic tunneling control reactivity premise. The presented consequences may further expose the possibility for the rational design of metal-based catalysts with systematic ligand/substituent tuning that can be performed efficiently through quantum mechanical tunneling.
      原文链接:
    • NSTL
    • Royal Soc Chemistry

    Diastereoselectively self-sorted low-symmetry binuclear metallomacrocycle and trinuclear metallocage

    Mishra Srabani SrotoswiniChand Dillip Kumar
    8页
    查看更多>>摘要：A pyridine/aniline appended unsymmetrical bis-monodentate ligand N-(3-aminophenyl)nicotinamide, Lun is synthesized via condensation of nicotinic acid with excess m-phenylene diamine. A low-symmetry binuclear complex of the Pd2L′2Lun2 type and an extremely rare trinuclear complex of the Pd3Lun6 type are produced by self-assembly of the ligand Lun with cis-protected palladium(ii) (i.e., PdL′) and palladium(ii), respectively. Two isomers (i.e. [(2,0), (2,0)] and [(1,1), (1,1)]-forms) are theoretically possible for the Pd2L′2Lun2-type complex whereas nine isomers can be envisaged in the case of the Pd3Lun6-type arrangement. However, one of the isomers of the Pd2L′2Lun2-type complex as well as the one for the Pd3Lun6-type complex are experimentally obtained. The exclusive formation of specific isomers could be predicted from the 1D/2D NMR study in the solution state and the DFT calculations in the gas phase/implicit solvent media. The formation of the predicted all-(1,1)-[Pd2(en)2Lun2](NO3)4 has been confirmed by a single-crystal XRD study. DFT calculations for the isomers of the Pd3Lun6-type arrangement show that a [cis(2,2), cis(2,2), cis(2,2)] isomer is energetically favourable than the alternatively predicted [trans(2,2), trans(2,2), trans(2,2)] isomer. Conformational changes within the build of the exclusively formed isomers are proposed on the basis of NMR study.
      原文链接:
    • NSTL
    • Royal Soc Chemistry

    A microporous chromium-organic framework fabricated via solvent-assisted metal metathesis for C2H2/CO2 separation

    Lu Ting-TingFan Ying-YiWang Xiao-NingWang Qiang...
    7页
    查看更多>>摘要：Removal of CO2 or C2H4 from C2H2 is still a challenging task due to their similar physical–chemical properties. Here, a bifunctional ligand decorated with amino and sulfoxide groups, 5′,5′′′′-sulfonylbis (2′-amino-[1,1′:3′,1′′-terphenyl]-4,4′′-dicarboxylic acid) (H4L), was employed to construct a new microporous iron-organic framework (Fe-MOF) with the formula [(Fe3O)(L)1.5(H2O)3]n. This MOF can serve as a parent structure to obtain the isostructural Cr-MOF by solvent-assisted metal metathesis. Furthermore, the gas adsorption and separation performance of these two MOFs were systematically investigated. Compared to Fe-MOF, Cr-MOF shows a moderately higher CO2, C2H2 and C2H4 uptake capacity. Additionally, Cr-MOF can selectively adsorb C2H2 over CO2 and C2H4. The separation potential towards C2H2/C2H4 and C2H2/CO2 was further established via IAST calculations of mixture adsorption equilibrium. IAST selectivity values of Cr-MOF are 3.4 for C2H2/C2H4 and 6.9 for C2H2/CO2 at 298 K and initial pressure, indicating its potential C2H2 separation ability.
      原文链接:
    • NSTL
    • Royal Soc Chemistry