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Herein, we report the synthesis and catalytic application of a new N,N′-dineopentyl-1,2-phenylenediamine-based bismuthenium cation (3). 3 has been synthesized via the treatment of chlorobismuthane LBiCl [L = 1,2-C6H4{N(CH2tBu)}2] (2) with AgSbF6, and was further used as a robust catalyst for the cyanosilylation of ketones under mild reaction conditions. Experimental studies and DFT calculations were performed to understand the mechanistic pathway. [ABSTRACT FROM AUTHOR]

The synthesis of novel stibenium cations and their catalytic application in cyanosilylation of carbonyl compounds have been described. Treatment of chlorostibine L1SbCl [L1 = 1,2-C6H4{N(CH2tBu)}2] (2) with 1 equiv. of AgOTf and AgSbF6 resulted in the formation of donor free L1SbOTf (3) and [L1Sb]+[SbF6]− (4), respectively. Among these three compounds, 4 exhibits excellent catalytic activity towards the cyanosilylation of aldehydes and ketones. [ABSTRACT FROM AUTHOR]

In our previous communication, we have reported the synthesis of a new chlorogermylene (B) featuring a pyridylpyrrolido ligand. This study details the preparation of a series of new germylenes and stannylenes starting from B. A transmetallation reaction between B and SnCl2 led to the analogous chlorostannylene (1) with the simultaneous elimination of GeCl2. This is a very unusual example of transmetallation between two elements of the same group. The preparation of 1via lithiation led to the formation of 2 as a side product, where the ortho C–H bond of the pyridine ring was activated and functionalized with a nBu moiety. Subsequently, B and 1 were used as precursors to generate germylene (4) and stannylene (5) featuring tris(trimethylsilyl)silyl (hypersilyl) moieties. We also prepared tetrafluoropyridyl germylene (6) by reacting 4 with C5F5N with the simultaneous elimination of (Me3Si)3SiF by utilizing the fluoride affinity of the silicon atom. As there is scarcity of Sn(II) compounds as single-site catalysts, we investigated 5 as a catalyst towards the hydroboration of aldehydes, ketones, alkenes and alkynes. All the compounds have been characterized by single-crystal X-ray diffraction and by state of the art spectroscopic studies. [ABSTRACT FROM AUTHOR]

• Base free HMF oxidation with RuMn oxides revisited. • Substantial activity loss when catalyst reused at full oxidation level. • Acidic product (FDCA and FFCA) induced Mn leaching from MnO 2 based supports. • Formation of Mn-FDCA complexe and reduction Mn AOS responsible for missing mass balance and activity loss. • Weak bases can suppress Mn leaching, Mn-FDCA complexation and preserve Mn AOS. 2,5-furandicarboxylic acid (FDCA) is a high value bio-based chemical useful for the production of next generation renewable polymers, epoxy-resins and surfactants. Herein, we show that the performance and stability of MnO 2 based oxidation catalysts used in FDCA production are considerably influence by process conditions (especially initial HMF conc. and presence of base additives). Although, base free aerobic oxidation of HMF to FDCA is known to be highly effective over Ru modified MnO 2 catalysts, our experiments showed considerable leaching of MnO 2 phase under reaction conditions with the formation of insoluble Mn-FDCA complexes. The formation of Mn-FDCA complex and Mn leaching was also supported by control experiments between FDCA and various Mn oxides under hydrothermal conditions and its structure confirmed by single crystal XRD. Formation of Mn-FDCA and Mn leaching was also identified as the underlying reason for carbon balance deficit, catalyst mass loss and deactivation observed upon reuse. [Display omitted] [ABSTRACT FROM AUTHOR]