•Antimony(III) and tin(IV) compounds with an amino(amido)silane ligand were synthesized.•These compounds were characterized by single-crystal X-ray diffraction.•The tin compound shows high catalytic activity in ROP of ε-caprolactone.Aminosilane bearing bulky substituents on nitrogen, LH2 (L = (NAr)2SiPh2, Ar = 2,6-iPr2C6H3) was reacted with n-BuLi (ratio 1:1) in toluene with a small amount of tetrahydrofuran resulting in [η1-Ph2Si(NHAr)ArNLi·2C4H8O] (1). Compound 1 was used to synthesize unusual monodentate complexes [(η1-Ph2SiNHAr)ArNSbCl2] (2) and [(η1-Ph2SiNHAr)ArNSnMe3] (3) by reacting with SbCl3 and Me3 SnCl, respectively. The three new compounds were characterized by elemental analysis, 1H NMR, 13C NMR and single-crystal X-ray structural analysis. Compound 3 shows high catalytic activity in ring-opening polymerization (ROP) of ε-caprolactone (ε-CL).Three new compounds, [η1-Ph2Si(NHAr)ArNLi·2C4H8O] (Ar = 2,6-iPr2C6H3) (1), [(η1-Ph2SiNHAr)ArNSbCl2] (2), and [(η1-Ph2SiNHAr)ArNSnMe3] (3), containing amino(amido)silane ligand were synthesized in good yield. All compounds were characterized by single-crystal X-ray diffraction. Compound 3 shows high catalytic activity in ring-opening polymerization of ε-caprolactone.

•Synthesis, characterization of two aluminum complexes [LAl(μ-S)2AlL] (1) and LAl(SeH)2 (2).•[LAl(μ-S)2AlL] (1) as bimetallic Lewis acid catalyst for the addition reaction of TMSCN to aldehydes.•[LAl(μ-S)2AlL] (1) can also as bimetallic Lewis acid catalyst for aldimine condensation reactions.Two aluminum complexes [LAl(μ-S)2AlL] (1) and [LAl(SeH)2] (2) were synthesized in good yield by reacting one equivalent of LAlH2 (L = HC(CMeNAr)2, Ar = 2,6-Et2C6H3) with one equivalent of S and with two equivalents of Se without any catalysts, respectively. Complexes 1 and 2 have been characterized by 1H and 13C NMR, elemental analyses, and single crystal X-ray structural analysis. Furthermore, the good catalytic activity of 1 as bimetallic Lewis acid catalyst for the addition reaction of TMSCN to aldehydes and aldimine condensation reactions, respectively, were investigated.[LAl(μ-S)2AlL] (1) and [LAl(SeH)2] (2) were synthesized and fully characterized. [LAl(μ-S)2AlL] (1) as a bimetallic Lewis acid catalyst for addition reaction of TMSCN to aldehydes and aldimine condensation reaction were reported.Download high-res image (33KB)Download full-size image

•Soluble aluminum hydrides function as catalysts.•Stoichiometric reactivity studies shed further light on the catalytic cycle.•Appropriate ligand design is important to proton mediate and electron transfer.•Activations usually occur via stepwise deprotonation or hydroalumination.•Catalytic mechanisms involve insertion/σ-bond metathesis, Lewis acid activation.The past decades have witnessed staggering progress in the chemistry of compounds with s- and p-block elements. Aluminum compounds, especially soluble aluminum hydrides, received wide explorations due to their high reactivity towards protonic reagents and unsaturated compounds containing multiple bonds such as CO, CNR, CN, and CC. Recent studies suggest that reactions employed aluminum hydrides usually occurred via deprotonation or hydroalumination, which exhibit great perspective in main group catalysis. These stoichiometric reactions often act as the initial step during the overall catalytic cycle. Appropriate ligands at the central Al atom are important for the activation of the substrates and the regeneration of the active catalytic molecules. In this review, we focus on the activation of carbonyl compounds, alkenes, and alkynes using soluble aluminum hydrides based on the previous stoichiometric reactions. Different mechanisms were proposed to explain the driving force for the turnover of the catalytic cycle in dehydrocoupling, hydroboration, and hydrosilylation. Moreover, aluminum hydrides stabilized by tridentate ligands, which function in the dehydrocoupling of benzylamine and dehydrogenation of formic acid, are also included in this review.

Novel molybdenum and tungsten complexes with tridentate bis(phenolate) ligands containing [O,X,O] donor atoms (X = S or Se), [MoO2LS] (1), [MoO2LSe] (2), [WO2LS] (3) and [WO2LSe] (4), were synthesized and characterized as functional models for molybdenum- and tungsten-dependent oxidoreductases. The catalytic oxo-transfer properties of 1–4 were investigated by oxo-transfer reactions from nitrate to PPh3 with a ratio of complex (1–4):PPh3:(Bu4N)(NO3−) = 1:10:20 and from DMSO to PPh3 with varied catalyst:PPh3 ratios. For the oxygen atom transfer reaction from nitrate to PPh3, the molybdenum compounds are catalytically more active than their tungsten analogues. Whereas for the oxygen atom transfer reaction from DMSO to PPh3, the tungsten compounds exhibit more efficient catalytic behavior than the molybdenum analogues. In all catalytic reactions, sulfur containing compounds have a higher catalytic ability than their selenium analogues. In comparison, all four compounds catalyze the oxygen atom transfer reaction from DMSO to PPh3 much more effectively than the oxidation of PPh3 with NO3−.Graphical abstractNovel molybdenum and tungsten complexes with tridentate bis(phenolate) ligands containing [O,X,O] donor atoms (X = S or Se), [MoO2LS] (1), [MoO2LSe] (2), [WO2LS] (3) and [WO2LSe] (4), were synthesized and characterized as functional models for molybdenum- and tungsten-dependent oxidoreductases. The catalytic oxo-transfer properties of 1–4 were investigated.Highlights► Molybdenum and tungsten complexes with ligands containing S and Se were synthesized. ► The employed ligands contain two phenolate donor atoms. ► These synthesized complexes were characterized well by all analysis data. ► The catalysis was investigated by oxo-transfer reactions from nitrate to PPh3. ► The catalysis was investigated by oxo-transfer reactions from DMSO to PPh3.

WOCl4 reacts with (Me3Si)2O and excess THF to give [WO2Cl2(THF)]4 (1), a new tetrameric tungsten(VI)-oxo complex, which was characterized and crystal structure was determined by X-ray crystallography. Complex 1 has a roughly square planar tetranuclear structure bridged by μ-oxo ligands. Each tungsten atom is coordinated by two bridging oxygens, one terminal oxygen, two “axial” chlorine atoms and one “equatorial” O-bonded THF ligand. One of the two μ-oxo ligands is similar to the terminal oxygen atom and the other one is similar to the coordinated oxygen atom of the THF ligand, respectively, which confirmed a previous proposal. Four WO3Cl2(THF) octahedral are associated by sharing corners. Complex 1 is different from three known tetrameric tungsten analogues in its structural arrangement and properties.A new tetrameric tungsten-oxo complex [WO2Cl2(THF)]4 (1) was synthesized, characterized, and its crystal structure was determined by X-ray single-crystal diffraction. The complex has a roughly square planar tetranuclear structure bridged by μ-oxo ligands.