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1.
Inorg Chem ; 59(3): 2051-2061, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31967459

RESUMO

Dioxygen O-O bond activation is a process for oxygenases and oxidases to perform biological functions and synthetic biomimetic catalysts to carry out oxygenation reactions using molecular O2 as an oxidant. Inspired by the experimental development of a CoIII-peroxo complex (i.e., [CoIII(TBDAP)(O2)]+, TBDAP = N,N-ditert-butyl-2,11-diaza[3.3](2,6)-pyridinophane) that exhibits dioxygenase-like reactivity to activate nitriles, a density functional theory (DFT) mechanistic study has been carried out to understand how the peroxo ligand is broken to activate nitriles. The study unveils that the O-O bond cleavage takes place via conversion to a CoII-superoxo complex aided by nitrile coordination, followed by formation of a five-membered intermediate via superoxo O2 radical nucleophilic attack at the nitrile carbon. Finally, a [1,3]-sigmatropic rearrangement-like process breaks the dioxygen bond. The otherwise difficult [1,3]-sigmatropic rearrangement is enabled by the mediation of CoIII(TBDAP) which alters a concerted rearrangement to a sequential process of O-O bond cleavage and N-O bond formation. Expectedly, the unveiling of the O-O bond cleavage mechanism could offer a clue for the development of biomimetic metal oxygenation catalysts.

2.
Org Lett ; 22(2): 453-457, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31913046

RESUMO

DFT study suggests that the C-H cleavage involved in the C(sp3)-H amination catalyzed by manganese perchlorophthalocyanine complex [MnIII(ClPc)]+ proceeds via hydride transfer (HYT), instead of hydrogen atom transfer (HAT), thus elucidating why the reaction favors aminating the electron-rich C-H bond, rather than that with smaller bond dissociation energy preferred by HAT. Detailed analyses indicate the HYT actually occurs via concerted electron and hydrogen atom transfers and the redox-active ClPc ligand enables the HYT.

3.
Adv Mater ; 31(39): e1901964, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31389096

RESUMO

Atomically thin oxychalcogenides have been attracting intensive attention for their fascinating fundamental properties and application prospects. Bi2 O2 Se, a representative of layered oxychalcogenides, has emerged as an air-stable high-mobility 2D semiconductor that holds great promise for next-generation electronics. The preparation and device fabrication of high-quality Bi2 O2 Se crystals down to a few atomic layers remains a great challenge at present. Here, molecular beam epitaxy (MBE) of atomically thin Bi2 O2 Se films down to monolayer on SrTiO3 (001) substrate is achieved by co-evaporating Bi and Se precursors in oxygen atmosphere. The interfacial atomic arrangements of MBE-grown Bi2 O2 Se/SrTiO3 are unambiguously revealed, showing an atomically sharp interface and atom-to-atom alignment. Importantly, the electronic band structures of one-unit-cell (1-UC) thick Bi2 O2 Se films are observed by angle-resolved photoemission spectroscopy (ARPES), showing low effective mass of ≈0.15 m0 and bandgap of ≈0.8 eV. These results may be constructive to the synthesis of other 2D oxychalcogenides and investigation of novel physical properties.

4.
Oncol Res ; 27(5): 601-611, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31053182

RESUMO

Baicalein, an active ingredient separated from Astragalus membranaceus, has shown its anticancer ability in various cancers. However, its effect on nasopharyngeal carcinoma has not been explored yet. The present study aimed to investigate the effect of baicalein on the growth, proliferation, apoptosis, and cell cycle of human nasopharyngeal carcinoma cells, as well as transplanted nude mouse xenograft. The results showed that baicalein inhibited the growth and proliferation of CNE1 and CNE2 cells in a time- and concentration-dependent manner. It also caused a significant increase in the number of cells in the G0/G1 phase and a decrease in the G2/M phase, thereby reducing the number of cells entering mitosis and inhibiting the proliferation of tumor cells. Baicalein also significantly induced apoptosis of CNE1 and CNE2 cells. Western blots showed that baicalein decreased the expression of Bcl-xl and Mcl-1 and increased the expression of Bax, Bad, and caspase 3, 8, and 9. In CNE1- and CNE2-transplanted tumors of mice, baicalein significantly inhibited tumor growth. In conclusion, baicalein could inhibit the growth and proliferation of human nasopharyngeal carcinoma cells, change their cell cycle, and induce apoptosis. Baicalein also effectively limits both CNE1- and CNE2-transplanted tumors in nude mice. Downregulation of Bcl-xl and Mcl-1 proteins and upregulation of Bax and Bad may be involved in the mechanism.


Assuntos
Antineoplásicos/uso terapêutico , Flavanonas/uso terapêutico , Carcinoma Nasofaríngeo/tratamento farmacológico , Neoplasias Nasofaríngeas/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/metabolismo , Astragalus propinquus/imunologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Medicina Tradicional Chinesa , Camundongos , Camundongos Nus , Ensaios Antitumorais Modelo de Xenoenxerto
5.
J Phys Chem Lett ; 10(8): 1866-1871, 2019 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-30875475

RESUMO

The intriguing properties of graphene have inspired the pursuit of two-dimensional materials with honeycomb structure. Here we achieved the synthesis of a monolayer transition-metal monochalcogenide AgTe on Ag(111) by tellurization of the substrate. High-resolution scanning tunneling microscopy, combined with low-energy electron diffraction, angle-resolved photoemission spectroscopy, and density functional theory calculations, demonstrates the planar honeycomb structure of AgTe. The first-principles calculations further predict that, protected by the in-plane mirror reflection symmetry, there are two Dirac node-line fermions existing in the free-standing AgTe when spin-orbit coupling (SOC) is ignored. In fact, the SOC leads to the gap opening, resulting in the emergence of the topologically nontrivial quantum spin Hall edge state. Importantly, our experiments evidence the chemical stability of the monolayer AgTe in ambient conditions, making it possible to study AgTe by more ex situ measurements and even to utilize AgTe in future electronic devices.

6.
Phys Rev Lett ; 122(6): 066802, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30822064

RESUMO

The observation of substantially enhanced superconductivity of single-layer FeSe films on SrTiO_{3} has stimulated intensive research interest. At present, conclusive experimental data on the corresponding electron-boson interaction is still missing. Here we use inelastic electron scattering spectroscopy and angle resolved photoemission spectroscopy to show that the electrons in these systems are dressed by the strongly polarized lattice distortions of the SrTiO_{3}, and the indispensable nonadiabatic nature of such a coupling leads to the formation of dynamic interfacial polarons. Furthermore, the collective motion of the polarons results in a polaronic plasmon mode, which is unambiguously correlated with the surface phonons of SrTiO_{3} in the presence of the FeSe films. A microscopic model is developed showing that the interfacial polaron-polaron interaction leads to the superconductivity enhancement.

7.
Chemistry ; 25(15): 3939-3949, 2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-30623497

RESUMO

Acceptorless dehydrogenative coupling (ADC) reactions generally involve a nucleophile (e.g., amine) as a coupling partner. Intriguingly, it has been reported that nitriles could also act as nucleophiles in ADC reactions, achieving the α-olefination of nitriles with primary or secondary alcohols by employing a manganese or ruthenium pincer complex as the catalyst, respectively. Although different mechanisms have been postulated for the two catalytic systems, the results of our DFT mechanistic study, reported herein, have allowed us to propose a unified mechanism to account for both nitrile α-olefinations. The reactions take place in four stages, namely alcohol dehydrogenation, nitrile activation to generate a nucleophilic metal species, coupling of an aldehyde or ketone with the metal species to form a C-C bond and to transfer a nitrile (Cα -)H atom to the carbonyl group, and dehydration by transferring the protonic (N-)H to the hydroxy group. A notable feature of the coupling stage is the activation of water or alcohol to give an intermediate featuring an OH- - or OR- -like group that activates a nitrile Cα -H bond. Moreover, the mechanism can even be applied to the base (KOtBu, modeled by the (KOtBu)4 cluster)-catalyzed Knoevenagel condensation of nitriles with ketones, which further indicates the generality of the mechanism and the resemblance of the metal pincer complexes to the (KOtBu)4 base. We expect these in-depth mechanistic insights and the finding of the resemblance of the metal pincer complexes to the (KOtBu)4 cluster could assist the development of new ADC reactions.

8.
Chem Commun (Camb) ; 54(77): 10870-10873, 2018 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-30204174

RESUMO

A DFT comparative mechanistic study unveils that the TBD-catalyzed reactions of amines with CO2 and hydrosilanes may either undergo a neutral mechanism or a mechanism involving free ions, depending on the polarity of the solvent. The nucleophilicity of the amines is an important factor to determine the chemoselectivities of the reactions to give formamide or aminal/N-methylated amine.

9.
Chem Asian J ; 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29905404

RESUMO

Nanometer-wide graphene nanoribbons can be synthesized from halogen aromatics through multistep on-surface reactions, but the catalytic role of extrinsic transition-metal atoms in these reactions are still to be explored. Here by low-temperature scanning tunneling microscopy, we investigated the on-surface synthesis of graphene nanoribbons from 10,10'-dibromo-9,9'-bianthryl precursors in the presence of Ni atoms. Ni atoms not only act as catalysts in debromination and lead to the formation of an organometallic intermediate at 300 K, but also prompt the fusion reaction between graphene nanoribbons at 673 K. Our work demonstrates a more efficient way to fabricate fused graphene nanoribbons.

10.
Adv Mater ; 30(30): e1802065, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29894006

RESUMO

Two-dimensional (2D) in-plane p-n junctions with a continuous interface have great potential in next-generation devices. To date, the general fabrication strategies rely on lateral epitaxial growth of p- and n-type 2D semiconductors. An in-plane p-n junction is fabricated with homogeneous monolayer Te at the step edge on graphene/6H-SiC(0001). Scanning tunneling spectroscopy reveals that Te on the terrace of trilayer graphene is p-type, and it is n-type on monolayer graphene. Atomic-resolution images demonstrate the continuous lattice of the junction, and mappings of the electronic states visualize the type-II band bending across the space-charge region of 6.2 nm with a build-in field of 4 × 105 V cm-1 . The reported strategy can be extended to other 2D semiconductors on patternable substrates for designed fabrication of in-plane junctions.

11.
Dalton Trans ; 47(23): 7709-7714, 2018 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-29796513

RESUMO

We computationally formulated a metal-free strategy to construct bifunctional active sites for reversible H2 activation, using a N-centered group as a Lewis basic site and a PV-centered group as a Lewis acidic site. By embedding the active sites into five-membered and 6-membered rings, we designed a series of molecules, some of which have feasible kinetic barriers to perform catalytic hydrogenation, calling for experimental realizations.

12.
Chemistry ; 24(27): 7010-7025, 2018 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-29709085

RESUMO

Titanium catalysis generally prefers redox-neutral mechanisms. Yet it has been reported that titanium could promote bond formations in a way similar to reductive elimination. Accordingly, redox catalytic cycles involving TiIV /TiII cycling have been considered. By studying, as an example, the carboamination of alkynes with alkenes and azobenzene catalyzed by the [TiIV ]=NPh imido complex, we performed DFT computations to gain an understanding of how the "abnormal" catalysis takes place, thereby allowing us to clarify whether the catalysis really follows TiIV /TiII redox mechanisms. The reaction first forms an azatitanacyclohexene by alkyne addition to the [TiIV ]=NPh bond, followed by alkene insertion. The azatitanacyclohexene can either undergo Cα -Cγ coupling, to afford bicyclo[3.1.0]imine, or ß-H elimination, to yield a [TiIV ]-H hydride, which then undergoes Cα =Cß or Cγ =Cδ insertion to give an α,ß- or ß,γ-unsaturated imine, respectively. Both the geometric and electronic structures indicate that the catalytic cycles proceed through redox-neutral mechanisms. The alternative redox mechanisms (e.g., by N-H or C-H reductive elimination) are substantially less favorable. We concluded that electronically, the TiIV catalysis intrinsically favors the redox-neutral mechanism, because a redox pathway would involve TiII structures either in the triplet ground state or in the high-lying open-shell singlet state, but the involvement of triplet TiII structures is spin-forbidden and that of singlet TiII structures is energetically disadvantageous.

13.
Dalton Trans ; 47(14): 4804-4819, 2018 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-29561047

RESUMO

It has been reported that RuH2(η2-H2)2(PCy3)2 (1) could mediate CO2 reduction by pinacolborane (HBpin), affording pinBOBpin (7), pinBOCH3 (8), pinBOCHO (9), pinBOCH2OBpin (10), and an unprecedented C2 species pinBOCH2OCHO (11), which meanwhile is converted to the Ru complexes, including the transient 3 (RuH(κ2-O2CH)(CO)(PCy3)2) and 5 (RuH{(µ-H)2Bpin}(CO)(PCy3)2), and the persistent 4 (RuH(κ2-O2CH)(CO)2(PCy3)2) and 6 (RuH2(CO)2(PCy3)2). To gain an insight into the catalysis, a DFT study was carried out. The study identified the key active catalyst to be the hydride 13 (RuH2(CO)(PCy3)2) and characterized the mechanisms leading to the experimentally observed species (3-11). By investigating the experimental system, we learned a new mechanism called σ-π coupling for CO2 decarbonylation. Under this mechanism, CO2 and HBpin first co-coordinate to the Ru center of 13, then σ-π coupling takes place, forming a B-O bond between CO2 and HBpin, Ru-H and Ru-C bonds, and simultaneously breaking the H-Bpin bond, followed by -OBpin group migration to the Ru center, completing the CO2 decarbonylation. An interesting feature regarding the Ru catalysis was the involvement of η1-Hη1-H → η2-H2 and η1-Hη1-Bpin → η2-HBpin reductions, which facilitated the oxidative H-Bpin addition or the coordination mode change of CO2 from η1-O to η2-CO for CO2 activation or σ-π coupling. The facilitation effects could be attributed to the reductions enhancing the electron donations from the Ru center to the antibonding orbitals of the activating bonds.

14.
ACS Nano ; 11(11): 11402-11408, 2017 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-29064665

RESUMO

Easy-axis magnetic anisotropy separates two magnetic states with opposite magnetic moments, and single magnetic atoms and molecules with large easy-axis magnetic anisotropy are highly desired for future applications in high-density data storage and quantum computation. By tuning the metalation reaction between tetra-pyridyl-porphyrin molecules and Fe atoms, we have stabilized the so-called initial complex, an intermediate state of the reaction, on Au(111) substrate, and investigated the magnetic property of this complex at a single-molecule level by low-temperature scanning tunneling microscopy and spectroscopy. As revealed by inelastic electron tunneling spectroscopy in magnetic field, this Fe-porphyrin complex has magnetic anisotropy energy of more than 15 meV with its easy-axis perpendicular to the molecular plane. Two magnetic states with opposite spin directions are discriminated by the dependence of spin-flip excitation energy on magnetic field and are found to have long spin lifetimes. Our density functional theory calculations reveal that the Fe atom in this complex, decoupled from Au substrate by a weak ligand field with elongated Fe-N bonds, has a high-spin state S = 2 and a large orbital angular momentum L = 2, which give rise to easy-axis anisotropy perpendicular to the molecular plane and large magnetic anisotropy energy by spin-orbit coupling. Since the Fe atom is protected by the molecular ligand, the complex can be processed at room or even higher temperatures. The reported system may have potential applications in nonvolatile data storage, and our work demonstrates on-surface metalation reactions can be utilized to synthesize organometallic complexes with large magnetic anisotropy.

15.
Chem Commun (Camb) ; 53(89): 12148-12151, 2017 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-29075699

RESUMO

We herein report a new H2 activation mechanism to elucidate the N-formylation of amines with CO2 and H2, catalyzed by Ru(ii) pincer complexes in the absence of exogenous additives. Furthermore, we show that the mechanism could be applied to other types of Ru(ii) pincer complexes and computed iron analogs.

16.
Nano Lett ; 17(8): 4619-4623, 2017 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-28657748

RESUMO

Tellurium (Te) films with monolayer and few-layer thickness are obtained by molecular beam epitaxy on a graphene/6H-SiC(0001) substrate and investigated by in situ scanning tunneling microscopy and spectroscopy (STM/STS). We reveal that the Te films are composed of parallel-arranged helical Te chains flat-lying on the graphene surface, exposing the (1 × 1) facet of (101̅0) of the bulk crystal. The band gap of Te films increases monotonically with decreasing thickness, reaching the near-infrared band for the monolayer Te. An explicit band bending at the edge between the monolayer Te and graphene substrate is visualized. With the thickness controlled in the atomic scale, Te films show potential applications of electronics and optoelectronics.

17.
Chem Sci ; 8(3): 2413-2425, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28451348

RESUMO

Early transition metals (TMs), such as titanium, generally resist undergoing reductive elimination to form C-X bonds due to their weak electronegativity. By analyzing the mechanism of the titanium-catalyzed synthesis of pyrroles from alkynes and diazenes, the present study revealed that titanium is able to promote C-N bond formation via an unconventional elimination pathway, passing through a comparatively stable masked TiII complex (i.e., IM4) rather than pyrrole directly. The formation of IM4 originates from the bilateral donation and back-donation between Ti and the pyrrole ligand. Formally, it could be considered that the two electrons resulting from the unconventional reductive elimination are temporarily buffered by back-donation to a symmetry-allowed unoccupied π-orbital of the pyrrole ring in IM4 rather than becoming a lone pair on a Ti center as adopted in the catalysis of late TMs. Because of its stability, IM4 requires additional oxidation by diazene to liberate pyrrole. The triplet counterpart (IM4T ) of IM4 is more stable than IM4, but the elimination is unlikely to reach IM4T , because the process is spin-forbidden and the spin-orbit coupling is weak. Alternatively, one may consider the forming pyrrole in IM4 as a redox-active ligand, reserving the two electrons resulting from the formal reductive elimination and then releasing the electrons when IM4 is oxidized by diazene. These insights allow us to propose the conditions for early TMs to undergo a similar elimination, whereby the forming product will have symmetry-allowed frontier molecular orbitals to form donation and back-donation bonding with a TM center and a substrate possessing a comparatively strong oxidizing ability to oxidize an IM4-like intermediate for product release. These insights may provide another way of constructing C-X bonds through a similar reductive elimination pathway, using early TM catalysts.

18.
J Clin Endocrinol Metab ; 102(5): 1548-1556, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28324025

RESUMO

Context: A sodium glucose cotransporter 2 (SGLT2) inhibitor, which increases urinary glucose excretion, was reported to decrease blood glucose levels and deaths among patients with type 2 diabetes mellitus (T2DM) and established cardiovascular disease. SLC5A2 and HNF1A mutations are associated with renal glycosuria, but their contributions to renal glycosuria in patients with T2DM are not well understood. Objective: To assess the clinical features of patients with T2DM and renal glycosuria and those with T2DM and low urinary glucose excretion (LUGE) and identify variants in the exons of SLC5A2 and HNF1A in patients with renal glycosuria and T2DM. Design: A total of 2044 Chinese patients with T2DM, including 64 patients with renal glycosuria and 58 patients with LUGE, were tested for their plasma and urine glucose concentrations after fasting. SLC5A2 and HNF1A exons were sequenced. Results: Compared with patients with LUGE, those with renal glycosuria were younger (P = 0.008), had lower body mass index (BMI) (P = 0.002) and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) values (P < 0.0001), and were less likely to have hypertension (P = 0.006). HOMA-IR and BMI were negatively associated with renal glycosuria after adjusting for age, sex, hypertension, and insulin therapy. One novel mutation (V359G) of SLC5A2 in 32 patients with renal glycosuria and one known mutation (R131W) of HNF1A in 28 nonobese patients with renal glycosuria were identified. Conclusions: These findings suggest that there are subtypes of T2DM characterized by different urinary glucose excretion and cardiovascular risk factors. SLC5A2 and HNF1A mutations partially explain renal glycosuria in patients with T2DM.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Glicosúria Renal/genética , Fator 1-alfa Nuclear de Hepatócito/genética , Transportador 2 de Glucose-Sódio/genética , Adulto , Distribuição por Idade , Idoso , Grupo com Ancestrais do Continente Asiático/genética , Índice de Massa Corporal , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/epidemiologia , Feminino , Variação Genética , Glicosúria Renal/epidemiologia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Hipertensão/epidemiologia , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Obesidade/epidemiologia , Análise de Sequência de DNA
19.
Phys Rev Lett ; 119(13): 136805, 2017 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-29341707

RESUMO

Plasmons, the collective excitations of electrons in the bulk or at the surface, play an important role in the properties of materials, and have generated the field of "plasmonics." We report the observation of a highly unusual acoustic plasmon mode on the surface of a three-dimensional topological insulator (TI) Bi_{2}Se_{3}, using momentum resolved inelastic electron scattering. In sharp contrast to ordinary plasmon modes, this mode exhibits almost linear dispersion into the second Brillouin zone and remains prominent with remarkably weak damping not seen in any other systems. This behavior must be associated with the inherent robustness of the electrons in the TI surface state, so that not only the surface Dirac states but also their collective excitations are topologically protected. On the other hand, this mode has much smaller energy dispersion than expected from a continuous media excitation picture, which can be attributed to the strong coupling with surface phonons.

20.
Chem Sci ; 8(11): 7637-7650, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29568428

RESUMO

DFT computations have been performed to gain insight into the mechanisms of formylation/methylation of amines (e.g. methylaniline (1a)/2,2,4,4-tetramethylpiperidine (2a)) with CO2 and hydrosilane ([Si]H2, [Si] = Ph2Si), catalyzed by 1,3,2-diazaphospholene ([NHP]H). Different from the generally proposed sequential mechanism for the methylation of amine with CO2, i.e. methylation proceeds via formylation, followed by further reduction of formamide to give an N-methylated amine, the study characterized a competition mechanism between formylation and methylation. The chemoselectivity originates from the competition between the amine and [NHP]H hydride to attack the formyloxy carbon of [Si](OCHO)2 (the insertion product of CO2 into [Si]H2). When the attack of an amine (e.g.1a) wins, the transformation affords formamide (1b) but would otherwise (e.g.2a) result in an N-methylated amine (2c). The reduction of formamide by [Si]H2 or [NHP]H is highly unfavorable kinetically, thus we call attention to the sequential mechanism for understanding the methylation of amine with CO2. In addition, the study has the following key mechanistic findings. The activation of CO2 by [NHP]H establishes an equilibrium: [NHP]H + CO2 ⇄ [NHP]OCHO ⇄ [NHP]+ + HCO2-. The ions play catalytic roles to promote formylation via HCO2- or methylation via[NHP]+ . In 1a formylation, HCO2- initiates the reaction, giving 1b and silanol byproducts. However, after the initiation, the silanol byproducts acting as hydrogen transfer shuttles are more effective than HCO2- to promote formylation. In 2a methylation, [NHP]+ promotes the generation of the key species, formaldehyde and a carbocation species (IM17+ ). Our experimental study corroborates our computed mechanisms.

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