Non-Saccharomyces yeast plays an important role in the initial stages of a wild ferment, as they are found in higher abundance in the vineyard than Saccharomyces cerevisiae. As such, there has been a focus in recent years to isolate these yeast species and characterize their effect on wine fermentation and subsequent aroma. This effect on wine aroma is often species and strain dependent, as the enzymatic profile of each yeast will determine which aroma compounds are formed as secondary metabolites. Semi-fermentative yeast, such as Hanseniaspora spp., Candida spp. and Metschnikowia pulcherrima, are commonly in high abundance in fresh grape must and have diverse enzymatic profiles, however they show a weak tolerance to ethanol, limiting their impact to the initial stages of fermentation. Fully fermentative non-Saccharomyces yeast, characterized by high ethanol tolerance, are often found at low abundance in fresh grape must, similar to Saccharomyces cerevisiae. Their ability to influence the aroma profile of wine remains high, however, due to their presence into the final stages of fermentation. Some fermentative yeasts also have unique oenological properties, such as Lanchancea thermotolerans and Schizosaccharomyces pombe, highlighting the potential of these yeast as inoculants for specific wine styles.
Stannylcarbynes [M(≡CSnMe3)(CO)2(Tp*)] [M = Mo, W; Tp* = hydrotris(dimethylpyrazol-1-yl)borate], which are readily obtained via the successive treatment of [M(≡CBr)(CO)2(Tp*)] with (n)BuLi and ClSnMe3, serve as effective carbyne transmetalation agents for the preparation of heteronuclear molecular gold carbido complexes such as [M(≡CAuPPh3)(CO)2(Tp*)] and the tetrameric golden ring complex [W(≡CAu)(CO)2(Tp*)]4, which are in turn able to transfer the carbido unit to palladium.
Addition of one equivalent of selenium to a germanium-phosphanide complex results in insertion of selenium into the Ge-P bond, not oxidation at germanium or phosphorus. Addition of excess selenium results in oxidation at phosphorus, although of germanium oxidation is still observed.
A new route to access low‐coordinate (β‐diketiminato)cadmium complexes has been developed. Treatment of [Cd(HMDS)2] with BDI‐H (HMDS = [N(SiMe3)2]; BDI = [{N(2,6‐iPr2C6H3)C(Me)}2CH]) forms [(BDI)Cd(HMDS)], which is a useful synthon for the generation of other low‐coordinate cadmium complexes such as anilido complex [(BDI)Cd(NH{N(2,6‐iPr2C6H3})(THF)], aryloxo complex [(BDI)Cd(O‐2,6‐tBu2C6H3)], as well as chloro complex [{(BDI)CdCl}2]. [(BDI)Cd(HMDS)] is extremely sensitive to hydrolysis, generating [{(BDI)Cd(OH)}2] upon exposure to “dry” tert‐butyl alcohol.
<p>Rising levels of carbon dioxide (CO₂) in the atmosphere has led to metal amide and alkoxide complexes being explored as potential CO₂ activators. A wide variety of M–O and M–N bonds have been shown to activate CO₂, however to date there are no examples with cadmium. A range of novel cadmium amide and alkoxide complexes have been synthesised, using the β-diketiminato ligand (BDI) as an ancilliary ligand. Initial reactivity studies have suggested CO₂ activation may be possible, although no products were isolated. Homonuclear metallic bonding (M–M) has been explored since the 1950’s and complexes containing M–M bonds are known for almost all transition and main group metals. There are only two reported Cd–Cd bonds, both using sterically bulky monoanionic ligands, like the β-diketiminato ligand. A novel β-diketiminato-cadmium chloride complex was synthesised and treated with a range of different reducing agents to generate a Cd–Cd bond. Different reactivities were observed for the reducing agents, however evidence of a Cd–Cd bond was not obtained. Group 14-16 materials, such as lead selenide, are p-type semi-conductors and have the potential to replacing silicon as a photon acceptor in solar cells. Lead selenide nanoparticles display quantum confinement effects, which allows one to tailor the band gap energies to maximise their absorbance of solar energy. The synthesis of PbSe nanoparticles is described in this study from the reaction between selenium and the lead complex [(BDIph)₂Pb], as well as from the decomposition of [(BDIdipp)PbSeP{Se}Cy₂]. Differences in the size and shapes of the nanoparticles was observed, highlighting the need for controlled nucleation and growth conditions.</p>
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