Origins of Narrowband Emission in Nitrogen/Carbonyl Multiresonance Thermally Activated Delayed Fluorescence Emitters: Steric Locks and Vibrational Coupling Effects.

The incorporation of -butyl groups and spiro-functionalization into C═O/N-embedded multiresonance thermally activated delayed fluorescence (MR-TADF) systems has yielded materials with superior narrowband emission and excellent color purity. To elucidate the mechanisms underlying the enhanced properties, we present a theoretical study of a series of fused nitrogen/carbonyl derivatives with narrower emission profiles. The key steric factors that contribute to narrowband emission were identified through energy decomposition analysis, induced by structural relaxation in states S and S.

The Impact of Education on Fertility During the Chinese Reform Era (1980-2018): Changes Across Birth Cohorts and Interaction with Fertility Policies.

We examined the influence of education on fertility decisions in contemporary China, drawing upon theoretical insights that emphasise the role of social institutions, gender relations, and life course dynamics in shaping family behaviour. This led us to propose a set of hypotheses that explain the differential effect of education on each parity. We used information on female cohorts born between 1960 and 1989, coming from the China Family Panel Studies for 2010-2018.

Mechanistic Study of B(CF)-Catalyzed Transfer Hydrogenation of Aldehydes/Ketones with PhSiH and Stoichiometric Water.

A DFT study was performed on the mechanisms of B(CF)-catalyzed transfer hydrogenation of aldehydes/ketones, using PhSiH and stoichiometric water. Path B2 includes a stepwise Piers S2-Si process, H transfer, and hydrolysis desilylation of siloxane, in which the hydrolysis desilylation step is rate-determining. Path C1 is first determined, involving a B(CF)-catalyzed concerted addition step of 2HO to carbonyl generating RRC(OH), a subsequent S2-Si dehydroxylation step of RRC(OH) giving RRC=OH and (CF)B-H, and final H transfer producing the respective alcohol RRCHOH.

From VIB- to VB-Group Transition Metal Disulfides: Structure Engineering Modulation for Superior Electromagnetic Wave Absorption.

The laminated transition metal disulfides (TMDs), which are well known as typical two-dimensional (2D) semiconductive materials, possess a unique layered structure, leading to their wide-spread applications in various fields, such as catalysis, energy storage, sensing, etc. In recent years, a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption (EMA) has been carried out. Therefore, it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.

Mechanistic insight into B(CF) catalyzed imine reduction with PhSiH under stoichiometric water conditions.

A DFT and experimental study on the mechanism of B(CF) catalyzed imine reduction is performed using PhSiH as reductant under stoichiometric water conditions. Ingleson's path B is reconfirmed here. And four novel (CF)B-OH induced pathways (paths C2, C3, D2 and D3) entirely different from all the previous mechanisms were determined for the first time.

Bis(1,3-dimethyl-1H-imidazolium) hexa-fluoro-silicate: the second monoclinic polymorph.

The title compound, 2C5H9N2 (+)·SiF6 (2-), (I), crystallized as a new polymorph, different from the previously reported one (Ia) [Light et al. (2007 ▶) private communication (refcode: NIQFAV). CCDC, Cambridge, England].

Bis(1,3-dimethyl-1H-imidazolium) hexa-fluoro-silicate methanol 0.33-solvate.

The title compound, 6C5H9N2 (+)·3SiF6 (2-)·CH3OH, (I), was prepared by recrystallization of the crude salt from methanol along with solvent-free 2C5H9N2 (+)·SiF6 (2-) (II). Crystals of these solvatomorphs can be separated manually. The solvate (I) crystallizes in a rare hexa-gonal space group P6/mcc.

Trichlorido(1,3-dimethyl-2,3-di-hydro-1H-imidazol-2-yl-idene-κC (2))aluminium(III).

The title compound, [Al(C5H8N2)Cl3], was prepared by a thermolytic decomposition under high-vacuum conditions and presents a formal adduct of an Arduengo carbene, 1,3-dimethyl-1H-imidazol-2-yl-idene, and aluminium trichloride. The Al atom adopts a pseudo-tetra-hedral CCl3 coordination environment. All N and C atoms, the Al atom, one of the Cl atoms, and all aromatic H atoms of the mol-ecule lie on a mirror plane.

2-{(E)-N-[2-(1H-Inden-3-yl)eth-yl]imino-meth-yl}-1H-imidazole.

The asymmetric unit of the title compound, C(15)H(15)N(3), contains two crystallographically independent mol-ecules with very similar geometries. The imidazole and indenyl planes are approximately orthogonal, making dihedral angles of 88.21 (9) and 83.

rac-(OC-6-33)-bis-[2-(N-Benzyl-methyl-imino-meth-yl-κN)-1H-imidazol-1-ido-κN]bis(ethyl-amido)-titanium(IV).

The title compound, [[Ti(C(2)H(10)N)(2)(C(11)H(10)N(3))(2)] or Ti(C(11)H(10)N(3))(2)(NEt(2))(2)], was prepared by direct reaction of 2-(N-phenyl-methyl-imino-meth-yl)-1H-imidazole and [Ti(NEt(2))(4)]. The Ti(IV) atom is in a pseudo-octa-hedral coordination environ-ment with the imidazolido-group N-atoms occupying apical positions and amido- and imino-N-atoms cis-located in the equatorial plane. The presence of two bidentate chelating ligands determines the chirality of the Ti(IV) atom.

{2-[(η-Cyclo-penta-dien-yl)diphenyl-meth-yl]-1H-imidazolido-κN}bis-(N,N-diethyl-amido)-titanium(IV).

The chemically achiral title mol-ecule, [Ti(C(4)H(10)N)(2)(C(21)H(16)N(2))], crystallizes in the chiral space group P2(1). All three N atoms coordinating to the Ti(IV) atom adopt planar environments [sums of valence angles = 359.5 (6), 360.

Trichlorido(tetra-hydro-furan){(1,2,3,3a,7a-η)-1-[2-(1-trimethyl-silyl-1H-imidazol-2-yl-κN)-1-methyl-prop-yl]inden-yl}zirconium(IV).

The title compound, [ZrCl(3)(C(19)H(25)N(2)Si)(C(4)H(8)O)], was prepared from bis-(N,N-dimethyl-amido-κN)(2-{2-[(1,2,3,3a,7a-η)-inden-yl]-2-methyl-prop-yl}-1H-imidazolido-κN(1))zirconium(IV) [(C(16)H(16)N(2))Zr(NMe(2))] by reaction with excess Me(3)SiCl in tetra-hydro-furan (THF) at elevated temperature. The crystal studied contained a minor non-merohedral twin contaminant [6.3 (4)%] which was taken into account during the refinement.

Detection of carbohydrates using a pre-column derivatization reagent 1-(4-isopropyl) phenyl-3-methyl-5-pyrazolone by high-performance liquid chromatography coupled with electrospray ionization mass spectrometry.

A reagent, 1-(4-isopropyl) phenyl-3-methyl-5-pyrazolone (PPMP) has been synthesized and used for high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) determination of pre-column labeled carbohydrates. Monosaccharides have been quantitatively converted into mono-PPMP-labeled derivatives with 28% aqueous ammonia as a catalyst at 80 degrees C during 70 min. Mono-PPMP derivatives have been demonstrated to exhibit better chemical stability than bis-PMP ones.

2-[(Cyclo-penta-1,3-dien-2-yl)diphenyl-meth-yl]-1-methyl-1H-imidazole.

The title compound, C(22)H(20)N(2), (Ib), forms along with 2-[(cyclo-penta-1,3-dien-1-yl)diphenyl-meth-yl]-1-methyl-1H-imid-azole, (Ia), which differs with respect to the position of the double-bonds in the C(5)H(5) ring, in an approximately 3:7 ratio (Ia:Ib; NMR spectroscopy data). However, in a single crystal, only compound (Ib) is present. H atoms of the CH(2) group (C(5)H(5) ring) were found from the difference Fourier synthesis and refined isotropically using the riding model.

Trichlorido{2-[2-(η-cyclo-penta-dien-yl)-2-methyl-prop-yl]-1-trimethyl-silyl-1H-imidazole-κN}titanium(IV) tetra-hydro-furan hemisolvate.

The title compound, [Ti(C(15)H(23)N(2)Si)Cl(3)]·0.5C(4)H(8)O, has been prepared from {2-[2-(η(5)-cyclo-penta-dien-yl)-2-methyl-prop-yl]-1H-imidazolyl-κN(1)}bis-(N,N-diethyl-amido-κN)titanium(IV), (C(12)H(14)N(2))Ti(NEt(2))(2), by reaction with excess of Me(3)SiCl in tetra-hydro-furan (THF) at 353 K. The crystal structure contains THF as adduct solvent, disordered around a center of inversion.

Two 18ē Ti(IV) eta5-Cp-tris(sec-amido)-type complexes derived from 1H-imidazol-2-yl side-chain functionalized cyclopentadienes.

Achiral {2-[2-(eta(5)-cyclopentadienyl)-2-methylpropyl]-1H-imidazolyl-kappaN(1)}bis(N,N-diethylamido-kappaN)titanium(IV), [Ti(C(4)H(10)N)(2)(C(12)H(14)N(2))], (I), and closely related racemic (SR)-{2-[(eta(5)-cyclopentadienyl)(phenyl)methyl]-1H-imidazolyl-kappaN(1)}bis(N,N-diethylamido-kappaN)titanium(IV), [Ti(C(4)H(10)N)(2)(C(15)H(12)N(2))], (II), have been prepared by direct reactions of Ti(NEt(2))(4) and the corresponding 1H-imidazol-2-yl side-chain functionalized cyclopentadienes. In compound (II), there are two crystallographically independent molecules of very similar geometries connected by a noncrystallographic pseudosymmetry operation akin to a 2(1) screw axis. All Ti-ligating N atoms in both (I) and (II) are in planar environments, which is indicative of an additional N-->Ti ppi-dpi donation.

(Diethyl ether){1-[2-(1-methyl-1H-imidazol-2-yl-κN)-1,1-diphenyl-ethyl]-(1,2,3,3a,7a-η)-inden-yl}lithium(I).

In the title compound, [Li(C(27)H(23)N(2))(C(4)H(10)O)], the Li atom possesses a nearly planar trigonal coordination environment (assuming the cyclo-penta-dienyl ring of the indenyl group occupies one coordination place). The diethyl ether ligand adopts a nearly planar W-type conformation.