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Crystallographic phase engineering plays an important part in the precise control of the physical and electronic properties of materials. In two-dimensional transition metal dichalcogenides (2D TMDs), phase engineering using chemical lithiation with the organometallization agent n -butyllithium ( n -BuLi), to convert the semiconducting 2H (trigonal) to the metallic 1T (octahedral) phase, has been widely explored for applications in areas such as transistors, catalysis and batteries 1 – 15 . Although this chemical phase engineering can be performed at ambient temperatures and pressures, the underlying mechanisms are poorly understood, and the use of n -BuLi raises notable safety concerns. Here we optically visualize the archetypical phase transition from the 2H to the 1T phase in mono- and bilayer 2D TMDs and discover that this reaction can be accelerated by up to six orders of magnitude using low-power illumination at 455 nm. We identify that the above-gap illumination improves the rate-limiting charge-transfer kinetics through a photoredox process. We use this method to achieve rapid and high-quality phase engineering of TMDs and demonstrate that this methodology can be harnessed to inscribe arbitrary phase patterns with diffraction-limited edge resolution into few-layer TMDs. Finally, we replace pyrophoric n -BuLi with safer polycyclic aromatic organolithiation agents and show that their performance exceeds that of n -BuLi as a phase transition agent. Our work opens opportunities for exploring the in situ characterization of electrochemical processes and paves the way for sustainably scaling up materials and devices by photoredox phase engineering. Chemical lithiation of two-dimensional transition metal dichalcogenides can be accelerated by up to six orders of magnitude using low-power illumination and a variety of phase transition agents.

The exfoliation of bulk 2H-molybdenum disulfide (2H-MoS 2 ) into few-layer nanosheets with 1T-phase and controlled layers represents a daunting challenge towards the device applications of MoS 2 . Conventional ion intercalation assisted exfoliation needs the use of hazardous n-butyllithium and/or elaborate control of the intercalation potential to avoid the decomposition of the MoS 2 . This work reports a facile strategy by intercalating Li ions electrochemically with ether-based electrolyte into the van der Waals (vdW) channels of MoS 2 , which successfully avoids the decomposition of MoS 2 at low potentials. The co-intercalation of Li + and the ether solvent into MoS 2 makes a first-order phase transformation, forming a superlattice phase, which preserves the layered structure and hence enables the exfoliation of bulk 2H-MoS 2 into bilayer nanosheets with 1T-phase. Compared with the pristine 2H-MoS 2 , the bilayer 1T-MoS 2 nanosheets exhibit better electrocatalytic performance for the hydrogen evolution reaction (HER). This facile method should be easily extended to the exfoliation of various transition metal dichalcogenides (TMDs).

A simple two-step and easily scalable method for the synthesis of cyclic and acyclic acetals of chloropropiolaldehyde was developed. They readily reacted with n -butyllithium to give stable crystalline acetals of lithiumpropiolaldehyde, which, being strong nucleophiles, reacted with chlorotrimethylsilane, chlorotrimethylstannane, and methyl chloroformate to form bifunctional acetylenes in high yields.

In this work, carbosilane dendrons of the first, second, and third generations were obtained on the basis of a natural terpenoid, limonene. Previously, we have shown the possibility of selective hydrosilylation and hydrothiolation of limonene. It is proved that during hydrosilylation, only the isoprenyl double bond reacts, while the cyclohexene double bond does not undergo into the hydrosilylation reaction. However, the cyclohexene double bond reacts by hydrothiolation. This selectivity makes it possible to use limonene as a dendron growth center, while maintaining a useful function—a double bond at the focal point. Thus, the sequence of hydrosilylation and Grignard reactions based on limonene formed carbosilane dendrons. After that, the end groups were blocked by heptamethyltrisiloxane or butyllithium. The obtained substances were characterized using NMR spectroscopy, elemental analysis and GPC. Thus, the proposed methodology for the synthesis of carbosilane dendrons based on the natural terpenoid limonene opens up wide possibilities for obtaining various macromolecules: dendrimers, Janus dendrimers, dendronized polymers, and macroinitiators.

The titanium amidate compound bis(N-tert-butylacetamido)(dimethylamido)(chloro)titanium was synthesized by the protonolysis of tris(dimethylamido)(chloro)titanium and structurally characterized by 1H and 13C NMR spectroscopy as well as X-ray diffraction. The compound does not appear to react cleanly nor readily with routine alkylating agents such as sec-butyllithium, benzyl potassium, or trimethylsilyl methyllithium.

Polymers synthesized with end-of-life consideration allow for recovery and reprocessing. “Living-anionic polymerization (LAP)” and hydrosilylation reaction were utilized to synthesize hair-end furan functionalized hairy nanoparticles (HNPs) with a hard polystyrene (PS) core and soft polydimethylsiloxane (PDMS) hairs via a one-pot approach. The synthesis was carried out by first preparing the living core through crosslinking styrene with divinylbenzene using sec-butyl lithium, followed by the addition of the hexamethylcyclotrisiloxane (D3) monomer to the living core. The living polymer was terminated by dimethylchlorosilane to obtain the HNPs with Si-H functional end groups. The furan functionalization was carried out by the hydrosilylation reaction between the Si-H of the functionalized HNP and 2-vinyl furan. Additionally, furan functionalized polystyrene (PS) and polydimethylsiloxane (PDMS) were also synthesized by LAP. 1H NMR and ATR-IR spectra confirmed the successful synthesis of the target polymers. Differential scanning calorimetry showed two glass transition temperatures indicative of a polydimethylsiloxane soft phase and a polystyrene hard phase, suggesting that the HNPs are microphase separated. The furan functionalized HNPs form thermo-reversible networks upon crosslinking with bismaleimide (BMI) via a Diels−Alder coupling reaction. The kinetics of the forward Diels–Alder reaction between the functionalized polymer and BMI were studied at three different temperatures: 50 °C, 60 °C, and 70 °C by UV–Vis spectroscopy. The activation energy for the furan functionalized HNPs reaction with the bismaleimide was lower compared to the furan functionalized polystyrene and polydimethylsiloxane linear polymers. The crosslinked polymer network formed from the Diels−Alder forward reaction dissociates at around 140–154 °C, and the HNPs are recovered. The recovered HNPs can be re-crosslinked at 50 °C. The results suggest that furan functionalized HNPs are promising building blocks for preparing thermo-reversible elastomeric networks.

[1,4,7,10-Tetraazacyclododecano-κ4N1,4,7,10(3-)]silicon(IV) chloride was synthesized from 1,4,7,10-tetraazacyclododecane (cyclen), n-butyl lithium, and silicon tetrachloride. The crystal structure analysis reveals that this cationic compound is a dimer in the solid state with pentacoordinate silicon atoms. The compound was characterized by melting point, IR, and NMR spectroscopy. The quantum chemical analysis shows that this compound might be an interesting precursor to generate a mononuclear silicon (IV) complex with unusual reactivity due to nearly planar tetracoordinate coordination geometry at the silicon atom.

Deprotonation of SiMe 2 (HNPbt) 2 proligand ( 1 ) by Li(NTms 2 ) (Tms = SiMe 3 ) base results in the formation of SiMe 2 (LiNPbt) 2 (Pbt = 2-(1,3-benzothiazol-2-yl)phenyl) in solution, which further reacts with GdCl 3 yielding [Li(THF) 4 ][Gd(SiMe 2 (NPbt) 2 ) 2 ] complex ( 2 ). In an attempt to obtain 2 with the use of n -butyllithium as a base, an unexpected product with an intricate structure - [Gd{Me 2 Si(NPbt)( o -NC 6 H 4 -C(Bu) 2 ( o -NHC 6 H 4 S))}(μ-NHPbt)Li(THF)] complex ( 3 ) is isolated and structurally characterized. The thiazole ring of one of the substituents of the silandiamide ligand is open in it, while two butyl groups are attached to the thiazole C2 carbon atom. In the reaction of 1 with an excess of butyllithium and YCl 3 , a product with the ligand also containing the C(Bu) 2 moiety is formed, which is shown by 1 H NMR. Apart from it, double complex salt [Li(THF) 4 ][Y(SiMe 2 (NPbt) 2 ) 2 ] ( 4 ) crystallized as a solvate with Et 2 O is isolated from the reaction mixture. In an attempt to obtain a monosubstituted [Y(SiMe 2 (NPbt))Cl] complex, compound 4 ·2THF forms along with several crystals of [{Y(SiMe 2 (NPbt) 2 )} 2 (μ-OBu) 2 ] complex ( 5 ) the structure of which is characterized by single crystal X-ray diffraction. The photophysical properties of compound 2 are studied in the THF solution and in the crystalline state.

Lithium aluminum titanium phosphate (LATP) is well-established as a crystalline electrolyte offering fast Li + diffusion pathways. However, when in contact with lithium metal, LATP forms a mixed-conducting interphase, potentially impacting the performance of LATP-based batteries. During lithiation, Ti 4+ is partially reduced to form Ti 3+ , and Li + occupies vacant sites within the NaSICON-type structure. Here, we employed 7 Li nuclear magnetic resonance (NMR) to investigate changes in Li + diffusivity induced by chemical lithiation using n -butyllithium. Chemical lithiation allowed us to mimic the structural and dynamic changes occurring within a lithium metal battery. Our findings reveal that lithiation does not hinder Li + diffusivity; rather, 7 Li NMR relaxation measurements indicate enhanced Li + ion hopping processes. Despite the formation of a lithiated interfacial layer that propagates inward, the dynamic properties of LATP—characterized by Li-rich and Li-poor domains—remain resilient. These results highlight that electrochemical degradation does not compromise the intrinsic ion dynamics of LATP. Lithium aluminum titanium phosphate is a crystalline electrolyte that offers fast Li + diffusion pathways, but is known to form a mixed-conducting interphase upon contact with lithium metal, potentially impacting battery performance. Here, 7 Li nuclear magnetic resonance is used to investigate changes in Li + diffusivity upon chemical lithiation, mimicking the structural and dynamic changes that occur within a lithium metal battery.

The structure of head and end groups of the polybutadiene synthesized by anionic polymerization of butadiene using tert -butyllithium as an initiator has been established using methods of NMR spectroscopy with T 2 -filter as well as 2D 1 H, 13 C HMBC and HSQC NMR spectroscopy. The spectral signals of head groups, which consist of tert -butyl groups connected with cis -1,4, trans -1,4 or 1,2-units of polybutadiene chain, were identified for the first time. A new method for the quantitative calculation of the content of head and end groups with different microstructures was proposed. It was shown that the total content of 1,4-units (both cis -1,4 and trans -1,4) in terminal groups is considerably higher than that in a main chain of polybutadiene.