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.

Process comprising the process steps of:

a) initially charging a pentenoic ester,
b) adding a ligand of structure 1 or 2:

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and a compound comprising a metal atom selected from: Rh, Ru, Co, Ir,
c) supplying H.sub.2 and CO,
d) heating the reaction mixture to convert the pentenoic ester to 5-formylpentanoic esters.

Various embodiments disclosed relate to a method of oxidizing sulfur-containing compounds. The method involves contacting a sulfur-containing compound with a helmet phthalocyaninato-type catalyst in the presence of an oxidant. The present invention also provides a method of removing undesired sulfur-containing compounds from a fluid, such as natural gas, crude oil or an aqueous waste stream.

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.

An efficient method for the preparation of backbone-substituted imidazolinium salts for use as N-heterocyclic carbene ligands, e.g., for organometallic catalysts is provided. These functionalized N-heterocyclic carbene ligands are used to prepare solid-supported catalysts, e.g., for olefin metathesis.

Disclosed are perfluorinated SABRE catalysts comprising a d-block element and a perfluorinated ligand, wherein the perfluorinated ligand is of Formula (I): [L.sub.m-(NHC)(YZ).sub.q] or a salt thereof. Also disclosed is a method of preparing a hyperpolarized substrate comprising a spin nucleus or nuclei using the perfluorinated SABRE catalysts, and isolating the resulting hyperpolarized substrate for administration to an animal. Further disclosed is a method of imaging a tissue of an animal suspected of having a disease or condition.