Search

Palladium nanoparticles stabilised by aniline modified polymer immobilised ionic liquid is a remarkably active catalyst for the hydrogenation of CO2 to formate; the initial TOF of 500 h−1 is markedly higher than either unmodified catalyst or its benzylamine and N,N-dimethylaniline modified counterparts and is among the highest to be reported for a PdNP-based catalyst. [ABSTRACT FROM AUTHOR]

Ditetrelenes R2E=ER2 (E=Si, Ge, Sn, Pb) substituted by multiple N/P/O/S‐donor groups are extremely rare due to their propensity to disaggregate into their tetrylene monomers R2E. We report the synthesis of the first fully phosphanyl‐substituted digermene {(Mes)2P}2Ge=Ge{P(Mes)2}2 (3, Mes=2,4,6‐Me3C6H2), which adopts a highly unusual structure in the solid state, that is both strongly trans‐bent and highly twisted. Variable‐temperature 31P{1H} NMR spectroscopy suggests that 3 persists in solution, but is subject to a dynamic equilibrium between two conformations, which have different geometries about the Ge=Ge bond (twisted/non‐twisted) due to a difference in the nature of their π‐stacking interactions. Compound 3 undergoes unprecedented, spontaneous decomposition in solution to give a unique GeI cluster {(Mes)2P}4Ge4⋅5 CyMe (7). [ABSTRACT FROM AUTHOR]

The Noyori‐Ikariya (arene)Ru(II)/TsDPEN precatalyst has been anchored to amorphous silica and DAVISIL through the η6‐coordinated arene ligand via a straightforward synthesis and the derived systems, (arene)Ru(II)/TsDPEN@silica and (arene)Ru(II)/TsDPEN@DAVISIL, form highly efficient catalysts for the asymmetric transfer hydrogenation of a range of electron‐rich and electron‐poor aromatic ketones, giving good conversion and excellent ee's under mild reaction conditions. Moreover, catalyst generated in situ immediately prior to addition of substrate and hydrogen donor, by reaction of silica‐supported [(arene)RuCl2]2 with (S,S)‐TsDPEN, was as efficient as that generated from its preformed counterpart [(arene)Ru{(S,S)‐TsDPEN}Cl]@silica. Gratifyingly, the initial TOFs (up to 1085 h−1) and ee's (96–97 %) obtained with these catalysts either rivalled or outperformed those previously reported for catalysts supported by either silica or polymer immobilized through one of the nitrogen atoms of TsDPEN. While the high ee's were also maintained during recycle studies, the conversion dropped steadily over the first three runs due to gradual leaching of the ruthenium. [ABSTRACT FROM AUTHOR]

Thereaction between 1,2-C6H4(CH2Cl)2and 2 equiv of in situ generated [R2P(BH3)]Li in THF givesthe corresponding o-phenylene-bridged bis(phosphine–boranes)1,2-C6H4{CH2P(BH3)R2}2(R = iPr (1a),Ph (2a), Cy (3a)). Treatment of 1a–3awith 2 equiv of nBuLi and2 equiv of tmeda yields the corresponding phosphine–borane-stabilizedcarbanion (PBC) complexes [1,2-C6H4{CHP(BH3)R2}2][Li(tmeda)]2·nL (R = iPr, n= 0 (1b); R = Ph, nL = THF (2b);R = Cy, nL = 2PhCH3(3b)).In contrast, treatment of 1awith 2 equiv of MeK, followedby 2 equiv of pmdeta, yields the monodeprotonation product [1,2-C6H4{CHP(BH3)iPr2}{CH2P(BH3)iPr2}][K(pmdeta)] (1c), due to a competing side reactionwith the solvent. Treatment of 1aand 3awith the less aggressive metalating agent PhCH2K givesthe corresponding dipotassium salts, the latter of which was isolatedas the adduct [1,2-C6H4{CHP(BH3)Cy2}2][K(pmdeta)]2(3c). X-raycrystallography reveals that 1b–3badopt similar structures in which the lithium ions are coordinatedby the carbanion centers and the borane hydrogen atoms of the phosphine–borane-stabilizedcarbanions. The potassium ion in 1cis coordinated bythe carbanion center and by B–H···K contactswith both borane groups, whereas the two potassium ions in 3cexhibit multihapto interactions with the aromatic ring of the PBCligand, along with B–H···K contacts. The reactionbetween ClSiMe2CH2CH2SiMe2Cl and 2 equiv of in situ generated [R2P(BH3)CH2]Li gives the bis(phosphine–boranes) [CH2SiMe2CH2P(BH3)R2]2(R = Me (4a), Ph (5a)). Treatmentof 4aor 5awith 2 equiv of nBuLi in THF readily yields the 1,6-dicarbanion complexes [CH2SiMe2CHP(BH3)R2]2[Li(THF)2]2(R = Me (4b), Ph (5b)). A similar reaction of 5a, 2 equiv of PhCH2K, and 2 equiv of pmdeta in THF gives the potassium complex[CH2SiMe2CHP(BH3)Ph2]2[K(pmdeta)]2(5c). Complex 5badopts a linear structure in the solid state, while 5cadopts an unusual polycyclic structure by virtue of bridging K···H–B–H···Kcontacts. [ABSTRACT FROM AUTHOR]

Group 1 metal molecular chemistry is dominated by a +1 oxidation state, while a 0 oxidation state is widespread in the metals. A more exotic, yet still available, oxidation state of group 1 metal is -1, i.e., alkalide. Reported as early as the 1970s, the alkalides appear in every modern inorganic chemistry textbook as an iconic chemical curiosity, yet their reactivity remains unexplored. This is due to their synthetic hurdles. In this work, we report the first facile synthesis of the archetypical alkalide complex, [Na + (2,2,2-cryptand)Na - ], which allows us to unveil a versatile reactivity profile of this once exotic species.

Palladium nanoparticles stabilised by aniline modified polymer immobilised ionic liquid is a remarkably active catalyst for the hydrogenation of CO 2 to formate; the initial TOF of 500 h -1 is markedly higher than either unmodified catalyst or its benzylamine and N , N -dimethylaniline modified counterparts and is among the highest to be reported for a PdNP-based catalyst.

Aromatic amides can be used to construct light-harvesting materials with valuable optical properties. The amide bond is formed using well-known coupling agents in near quantitative yield, as illustrated here through the synthesis of two boron dipyrromethene derivatives bearing an amide linkage. The primary concern with acyl amides is rotation around the C-N bond, leading to cis and trans isomers. Using NMR spectroscopy, quantum chemical calculations and critical comparison to simpler benzamides, the stereochemistry of the target compounds has been addressed. The N-cyclohexyl derivative gave diffraction quality crystals that established a trans geometry for the amide bond. Quantum chemical calculations support the trans geometry as being the lowest-energy structure in solution but indicate that inversion of the aryl ring is an important structural feature. Indeed, rotation around the C(sp 2 )-C(aryl) bond has a strong influence on the solution-phase NMR spectra. The amide connection has minimal effect on the photophysical properties., (© 2023 Wiley-VCH GmbH.)

Ditetrelenes R 2 E=ER 2 (E=Si, Ge, Sn, Pb) substituted by multiple N/P/O/S-donor groups are extremely rare due to their propensity to disaggregate into their tetrylene monomers R 2 E. We report the synthesis of the first fully phosphanyl-substituted digermene {(Mes) 2 P} 2 Ge=Ge{P(Mes) 2 } 2 (3, Mes=2,4,6-Me 3 C 6 H 2 ), which adopts a highly unusual structure in the solid state, that is both strongly trans-bent and highly twisted. Variable-temperature 31 P{ 1 H} NMR spectroscopy suggests that 3 persists in solution, but is subject to a dynamic equilibrium between two conformations, which have different geometries about the Ge=Ge bond (twisted/non-twisted) due to a difference in the nature of their π-stacking interactions. Compound 3 undergoes unprecedented, spontaneous decomposition in solution to give a unique Ge I cluster {(Mes) 2 P} 4 Ge 4 ⋅5 CyMe (7)., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)