This mini-review briefly describes the recent progress in the design and development of catalysts based on the presence of ionic liquids. In particular, the focus was on heterogeneous systems (supported ionic liquid (IL) phase catalysts (SILPC), solid catalysts with ILs (SCILL), porous liquids), which due to the low amounts of ionic liquids needed for their production, eliminate basic problems observed in the case of the employment of ionic liquids in homogeneous systems, such as high price, high viscosity, and efficient isolation from post-reaction mixtures.

Platinum and rhodium complexes ligated by imidazolium substituted phosphine were obtained with high yields and applied as efficient catalysts.

Six new air-stable anionic platinum complexes were synthesized in simple reactions of piperidinium [BMPip]Cl or pyrrolidinium [BMPyrr]Cl ionic liquids with platinum compounds ([Pt(cod)Cl₂] or K₂[PtCl₆]). All these compounds were subjected to isolation and spectrometric characterization using NMR and ESI-MS techniques. Furthermore, the determination of melting points and thermal stability of the above derivatives was performed with the use of thermogravimetric analysis. The catalytic performance of the synthesized complexes was tested in hydrosilylation of 1-octene and allyl glycidyl ether with 1,1,1,3,5,5,5-heptamethyltrisiloxane. The study has shown that they have high catalytic activity and are insoluble in the reaction medium which enabled them to isolate and reuse them in consecutive catalytic cycles. The most active complex [BMPip]₂[PtCl₆] makes it possible to conduct at least 10 catalytic runs without losing activity which makes it an attractive alternative not only to commonly used homogeneous catalysts, but also to heterogeneous catalysts for hydrosilylation processes. The activity of the studied catalysts is also affected by the kind of anion and, to some extent, the kind of cation.

Chlorophyllin (which was used as sensitizer) was adsorbed onto a synthetic titania–silica oxide system, prepared via a sol–gel method. It was investigated how the adsorption process was affected by the initial concentration of chlorophyllin and the contact time of the solution. The physicochemical and structural properties of the inorganic support were comprehensively analyzed, including determination of the dispersive properties and morphology of the material (particle size distribution, SEM image), crystalline structure (XRD), chemical composition (EDS), parameters of the porous structure (low-temperature N₂ sorption) and thermal stability (TGA/DTA). The effectiveness of chlorophyllin adsorption on TiO₂–SiO₂ was examined by Fourier transform infrared spectroscopy. The degree of coverage of the inorganic support with chlorophyllin was calculated from the Berendsen and de Golan equation based on BET and elemental analysis results. The kinetics of the adsorption of chlorophyllin onto the synthetic titania–silica oxide system were also determined. The experimental data correspond directly to a pseudo-second-order model. Moreover, the photocatalytic activity of selected TiO₂–SiO₂/chlorophyllin hybrids with respect to the decomposition of C.I. Basic Violet 10 dye was investigated. It was found that the titania–silica hybrids conjugated with chlorophyllin exhibited higher photocatalytic activity in the degradation of C.I. Basic Violet 10 than the pure TiO₂–SiO₂ material. Moreover, the kinetics of the photocatalytic degradation of selected organic compound was determined based on the Langmuir–Hinshelwood equation, assuming the pseudo-first-order reaction.

Rhodium complexes ligated by imidazolium-substituted phosphine were used as catalysts in the hydrosilylation of alkynes (1-heptyne, 1-octyne, and phenylacetylene) with 1,1,1,3,5,5,5-heptamethyltrisiloxane (HMTS) or triethylsilane (TES). In all cases, the above complexes showed higher activity and selectivity compared to their precursors ([Rh(PPh₃)₃Cl] and [{Rh(µ-Cl)(cod)}₂]). In the reactions with aliphatic alkynes (both when HMTS and TES were used as hydrosilylating agents), β(Z) isomer was mainly formed, but, in the reaction of phenylacetylene with TES, the β(E) product was formed. The catalysts are very durable, stable in air and first and foremost insoluble in the reactants which facilitated their isolation and permitted their multiple use in subsequent catalytic runs. They make a very good alternative to the commonly used homogeneous catalysts.