Methods for asymmetric cis-dihydroxylation (“AD”) of quinones to produce cis-diols of quinones with high yield (i.e. a yield ≥30%) and high enantioselectivity (i.e. an enantiometric excess ≥30%) are disclosed. The method uses an iron-based catalyst, such as one or more Fe(II) complexes, as the catalyst, and can be performed under mild reaction conditions (e.g. a temperature ≤50° C. at 1 atom in open air). The method generally includes: (i) maintaining a reaction mixture at a temperature for a period of time sufficient to form a product, where the reaction mixture contains a quinone, one or more iron-based catalyst(s), and a solvent, and where the product contains a chiral cis-diol. Optionally, the method also includes adding an oxidant into the reaction mixture prior to and/or during step (i), such as a hydrogen peroxide solution.

A simple approach to produce mixed Cu/Cu.sub.2O nanocrystals having a specific morphology by controlling the reaction temperature during Cu/Cu.sub.2O nanocrystals synthesis. Other variables are kept constant, such as the amount of reactants, while the reaction temperatures is maintained at a predetermined temperature of 70 C., 30 C. or 0 C., which are used to produce different and controlled morphologies for the Cu/Cu.sub.2O nanocrystals. The reaction mixture includes a copper ion contributor, a capping agent, a pH adjustor, and reducing agent. The reaction mixture is held at the predetermined temperature for three hours to produce the Cu/Cu.sub.2O nanocrystals. The synthesis method has advantages such as mass production, easy operation, and high reproducibility.

A method for separating a homogeneous catalyst from a solution includes forming a host-guest compound between a first isomer of the catalyst and inclusion compound in the solution and isolating the host-guest compound from the solution. The catalyst may be released from the inclusion compound by converting the first isomer of the catalyst to a second isomer of the catalyst.

A chemical reaction is catalyzed in an organic solvent using a water soluble N-heterocyclic carbene homogeneous catalyst to form a reaction mixture. An aqueous phase in the reaction mixture. A solvent in which the catalyst is insoluble is added to the reaction mixture, causing the catalyst to migrate to the aqueous phase to form a catalyst-laden aqueous phase. The catalyst is extracted from the catalyst-laden aqueous phase.

A method for separating a homogeneous catalyst from a solution includes forming a host-guest compound between a first isomer of the catalyst and inclusion compound in the solution and isolating the host-guest compound from the solution. The catalyst may be released from the inclusion compound by converting the first isomer of the catalyst to a second isomer of the catalyst.

A chemical reaction is catalyzed in an organic solvent using a water soluble N-heterocyclic carbene homogeneous catalyst to form a reaction mixture. An aqueous phase in the reaction mixture. A solvent in which the catalyst is insoluble is added to the reaction mixture, causing the catalyst to migrate to the aqueous phase to form a catalyst-laden aqueous phase. The catalyst is extracted from the catalyst-laden aqueous phase.

A method for separating a homogeneous catalyst from a solution includes forming a host-guest compound between a first isomer of the catalyst and inclusion compound in the solution and isolating the host-guest compound from the solution. The catalyst may be released from the inclusion compound by converting the first isomer of the catalyst to a second isomer of the catalyst.

This describes homogeneous catalysts that are recoverable from solution by being phase selective and through host-guest interactions. An example of a method includes separating a water soluble N-heterocyclic carbene homogeneous catalyst from a solution by: (a) forming a host-guest compound between the catalyst and an inclusion compound in the solution; and (b) isolating the host-guest compound from the solution.

A simple approach to produce mixed Cu/Cu.sub.2O nanocrystals having a specific morphology by controlling the reaction temperature during Cu/Cu.sub.2O nanocrystals synthesis. Other variables are kept constant, such as the amount of reactants, while the reaction temperatures is maintained at a predetermined temperature of 70 C., 30 C. or 0 C., which are used to produce different and controlled morphologies for the Cu/Cu.sub.2O nanocrystals. The reaction mixture includes a copper ion contributor, a capping agent, a pH adjustor, and reducing agent. The reaction mixture is held at the predetermined temperature for three hours to produce the Cu/Cu.sub.2O nanocrystals. The synthesis method has advantages such as mass production, easy operation, and high reproducibility.

A method for separating a homogeneous catalyst from a solution includes forming a host-guest compound between a first isomer of the catalyst and inclusion compound in the solution and isolating the host-guest compound from the solution. The catalyst may be released from the inclusion compound by converting the first isomer of the catalyst to a second isomer of the catalyst.