Carbonyl olefinations are among the most important organic syntheses that form C=C bonds, as they usually have high yields and in addition offer excellent stereoselectivity. Due to these advantages, carbonyl olefinations have important pharmaceutical and industrial applications. These reactions contain an additional step of an α-functionalized carbanion to an aldehyde or ketone to produce alkenes, but syntheses performed using metal carbene complexes are also known. The Wittig reaction is an example of carbonyl olefination, one of the best ways to synthesize alkenes. This involves the chemical reaction between an aldehyde or ketone with a so-called Wittig reagent, for instance phosphonium ylide. Triphenylphosphine-derived ylides and trialkylphosphine-derived ylides are the most common phosphorous compounds used as Wittig reagents. The Wittig reaction is commonly involved in the synthesis of novel anti-cancer and anti-viral compounds. In recent decades, the use of ultrasound on the Wittig reaction (and on different modified Wittig syntheses, such as the Wittig–Horner reaction or the aza-Wittig method) has been studied as a green synthesis. In addition to the advantage of green synthesis, the use of ultrasounds in general also improved the yield and reduced the reaction time. All of these chemical syntheses conducted under ultrasound will be described further in the present review.

A paramagnetic A₃B-type Mn(III)-porphyrin was synthesized and characterized by physical–chemical methods (UV-Vis, FT-IR, ¹H-NMR spectroscopy). The obtained compound was tested as a sensitive material for the spectrophotometric and potentiometric detection of iodine species. Using UV-Vis spectroscopy, the triiodide anions could be detected with high precision in the concentration interval of 1.02 × 10⁻⁵ to 2.3 × 10⁻⁵ M, with an LOD of 9.44 × 10⁻⁶ M. The PVC-based electrode using DOP as a plasticizer showed a sensitivity toward iodide in a wide concentration range of 1.0 × 10⁻⁵ to 1.0 × 10⁻¹ M, with an LOD of 8.0 × 10⁻⁶ M. Both methods are simple, low-cost, and efficient for the detection of iodine species in synthetic samples and pharmaceuticals.

A new sensing material, Pt(II)-5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin (Pt(II)-COOH-TPOPP), was synthesized and characterized. Polymeric membranes containing the porphyrin and three different plasticizers were used as an electroactive material for a new anion-selective sensor. The best composition of the membrane was the one plasticized with dioctylsebacate (DOS), the obtained sensor being citrate-selective in a linear range of 5 × 10⁻⁷–1 × 10⁻¹ M citrate. The slope was Nernstian (19.73 mV/decade) with good selectivity towards a number of interfering anions and a lifetime of five weeks.

The adsorption properties of two coordination polymers, resulting from the reaction of divalent metal (Ca²⁺ or Co²⁺) salts with (2-carboxyethyl)(phenyl)phosphinic acid, are presented in this paper. The structural and textural characterization before and after adsorption experiments is presented. The adsorbent materials were prepared using the hydrothermal procedure. The compound Ca[O₂P(CH₂CH₂COOH)(C₆H₅)]₂ (CaCEPPA) has a layered topology, with the phenyl groups oriented into the interlayer space and crystallizes in the monoclinic system. Compound Co₂[(O₂P(CH₂CH₂COO)(C₆H₅)(H₂O)]₂·2H₂O (CoCEPPA) has a 1D structure composed of zig-zag chains. The adsorption performances of CaCEPPA and CoCEPPA materials were tested in the removal of cadmium and lead from aqueous solutions. The optimum pH of ions adsorption was found to be five for both adsorbent materials. Pseudo-first and second-order kinetic models were used for fitting kinetic experimental data, and Langmuir and Freundlich isotherms were used for modeling the equilibrium experimental data. The pseudo-second-order kinetic model and Langmuir isotherm best described the adsorption of Cd and Pb ions onto the studied materials, judging from the results of the error function (correlation coefficient, sum of square error, chi-square test, and average relative error) analysis. The studied materials present a higher affinity for Cd ions compared with the adsorption capacity developed for the removal of Pb ions from aqueous solutions. CoCEPPA showed the highest adsorption performance in the removal process of metal ions from aqueous solutions compared with CaCEPPA (q_m = 54.9 mg Cd²⁺/g of CoCEPPA, q_m = 36.5 mg Cd²⁺/g of CaCEPPA).

In the present work, novel organic–inorganic hybrid materials containing boron, zirconium, and phosphorus were synthesized at different molar ratios, using the sol–gel method, starting from zirconyl chloride hexa-hydrate, triethyl borate, and phenyl phosphonic acid as the precursors. The sol–gel process is used for the first time in the present work in order to obtain organic–inorganic hybrids (or the so-called inorganic polymers) containing together boron, zirconium, and phosphorus. The sol–gel syntheses were performed at room temperature in ethanol. Zirconium containing compounds are already well known for their applications in medicine in restorative or prosthetic devices, including dental implants, knee and hip replacements, middle-ear ossicular chain reconstruction, and so on. Zirconium is a strong transition metal, which started to replace hafnium and titanium in the last decade in important applications. On the other hand, boron has the capability (similar to carbon) to form stable covalently bonded molecular networks. In addition to this capability, boron also offers mixed metallic and nonmetallic properties, because of its place on the periodic table, at the border between metals and nonmetals. Boron is responsible for the higher thermal stability of synthesized hybrid compounds. In the structure of those hybrid compounds, zirconium, boron, and phosphorus atoms are always connected via an oxygen atom, by P-O-Zr, Zr-O-Zr, or Zr-O-B bridges.

A Ni/Cu-containing phosphinate material based on 2-carboxyethyl(phenyl)phosphinic acid was synthesized under hydrothermal conditions and characterized using FT-IR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopy) and EDAX (Energy Dispersive X-ray Analysis) analysis. The FT-IR spectra suggest the coordination of the phosphinate group to the metal, while SEM revealed compact aggregated particles of the compound. EDAX analysis confirmed the simultaneous presence of both Ni(II) and Cu(II) metals in the synthesized material. DFT (Density Functional Theory) calculations performed on the corresponding mononuclear Ni-CEPPA and Cu-CEPPA models indicated that the Cu complex possesses a smaller HOMO–LUMO energy gap (2.72 eV) than the Ni analog (3.43 eV), suggesting higher electronic reactivity. The obtained material was preliminarily evaluated for Methylene Blue removal, exhibiting an adsorption capacity of 170.24 mg/g. These results suggest that mixed Ni/Cu phosphinate materials may represent potential candidates for adsorption-related applications.