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New conjugated (BDT-TTBTBTT)n copolymers are featured as promising hole-transport materials for n–i–p perovskite solar cells delivering efficiencies of up to ∼19%.

New small molecules bearing either phenylene or naphthalene core in combination with thiophene and rhodanine periphery moieties were synthesized by the Stille cross-coupling reaction. Their evaluation for prototypes of organic solar cells showed that replacing phenylene moiety by the naphthalene one caused decrease in the HOMO energy, while the open-circuit voltage and fill factors of solar cells based on these materials were significantly improved to manifest maximum power conversion efficiencies to 5.3%.

Two novel highly soluble bis(pyrrolidino)[60]fullerenes were synthesized and investigated as promising electron acceptor materials for organic solar cells. Reduced electron affinity of bis(pyrrolidino)[60]fullerenes as compared to the reference [60]PCBM enabled a spectacular increase in open-circuit voltage of organic bulk heterojunction solar cells by ~200 mV while using model P3HT and PCDTBT electron donor polymers. In addition to the improved optoelectronic properties, bis(pyrrolidino)[60]fullerenes were found to be resistant towards the photochemical cross-linking in contrast to conventional [60]PCBM and conjugated polymers. Most importantly, the designed fullerene derivatives efficiently suppressed photooxidation of conjugated polymers as revealed by ESR spectroscopy, which features a tremendous potential of applying these materials in the development of efficient and durable organic photovoltaics.

New organohypervalent iodine compounds, arylbenziodoxaborole triflates, were prepared from 1-acetoxybenziodoxaboroles and arenes by treatment with trifluoromethanesulfonic acid under mild conditions. Single crystal X-ray crystallography of these compounds revealed a pseudocyclic structure with a short intramolecular interaction of 2.698 to 2.717 A between oxygen and iodine in the benziodoxaborole ring. These new pseudocyclic aryliodonium salts readily generate aryne intermediates upon treatment with water at room temperature. The generated aryne intermediates react with various substrates to give the corresponding aryne adducts in moderate to good yields. Furthermore, the new benzyne precursors can also work as arylating reagents towards aromatic rings. The aryne intermediates generated from arylbenziodoxaborole triflates selectively react with tert-butyl phenol forming products of ortho arylation in moderate yields.

Hypervalent iodine catalyzed oxidation of aldoximes using oxone as a terminal oxidant generates nitrile oxides, which react with alkenes and alkynes to give the corresponding isoxazolines and isoxazoles in moderate to good yields. This reaction involves active hypervalent iodine species formed in situ from catalytic iodoarene and oxone in the presence of hexafluoroisopropanol in aqueous methanol solution.

A new hypervalent iodine(V) compound, potassium 4-iodylbenzenesulfonate, was prepared by the oxidation of 4-iodobenzensulfonic acid with Oxone in water. This potassium salt can be further converted into 4-iodylbenzenesulfonic acid by treatment with the acidic form of Amberlyst 15 in water. A single-crystal X-ray structure of potassium 4-iodylbenzenesulfonate revealed the presence of polymeric chains in the solid state due to a combination of numerous intra- and intermolecular interactions. Potassium 4-iodylbenzenesulfonate will likely find many practical applications as a thermally stable and water-soluble hypervalent iodine-based oxidant, particularly useful as a reagent for oxidative iodination of aromatic substrates. This reagent can be effectively recovered from the reaction mixture (92 % recovery) by treatment of the aqueous layer with Oxone at 60 °C for 2 h, followed by filtration of the precipitate.

A series of heterocyclic compounds containing trivalent iodine, oxygen, and boron in a five-membered ring were prepared and structurally investigated by X-ray crystallography. 1-Chloro-4-fluoro-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol-3-ol was synthesized by chlorination of 2-fluoro-6-iodophenylboronic acid followed by treatment of the intermediate iododichloride with water. 1-Acetoxy-4-fluoro-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol-3-ol, 1-acetoxy-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol-3-ol, and similar 1-substituted trifluoroacetate derivatives of benziodoxaborole were prepared the hypochlorite oxidation of 2-fluoro-6-iodophenylboronic acid or 2-iodophenylboronic acid in acetic or trifluoroacetic acid, respectively. 1-Acetoxy substituted benziodoxaborole can be further converted to the respective trifluoroacetate by treatment with trifluoroacetic acid or to the 1-hydroxy derivative by basic hydrolysis with aqueous NaHCO(3). X-ray structural studies of 1-chloro- and 1-trifluoroacetoxy substituted benziodoxaboroles 13, 17, and 18 have shown the presence of a planar five-membered heterocyclic ring with unusually short endocyclic I-O bond distance of 2.04-2.09 Å. Slow crystallization of 4-fluoro-1-trifluoroacetoxy-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol-3-ol from methanol resulted in the formation of a tetrameric macrocyclic structure 21 resulting from self-assembly of the initially formed 4-fluoro-1,3-dimethoxy-1H-1λ(3)-benzo[d][1,2,3]iodoxoborol. Structural parameters of the five-membered iodoxoborol ring, such as the planar geometry and the short B-O and O-I bonds lengths in 13, 17, and 18 compared to those in 21 and known benziodoxoles are indicative of partially aromatic character of this ring. Density functional theory (DFT) predicted NIST (0) and NIST (1) indexes for 1-chloro- and 1-trifluoroacetoxy substituted benziodoxaboroles, however, are indicative of significantly lower aromaticity compared to the classic aromatic systems.

Hypervalent iodine catalyzed oxidation of aldoximes using oxone as a terminal oxidant generates nitrile oxides, which react with alkenes and alkynes to give the corresponding isoxazolines and isoxazoles in moderate to good yields. This reaction involves active hypervalent iodine species formed in situ from catalytic iodoarene and oxone in the presence of hexafluoroisopropanol in aqueous methanol solution.

Isoxazolines can be efficiently synthesized in good yields via a hypoiodite mediated catalytic oxidative cyclization of aldoximes and alkenes. This reaction involves active iodine species generated in situ from catalytic amounts of KI and Oxone.

A thermally stable and water-soluble hypervalent iodine oxidant for oxidative iodination of aromatic substrates is synthesized.

This review summarizes the chemistry of iodonium salts with emphasis of their synthetic applications. The preparation and reactions of diaryliodonium, alkenyl(aryl)iodonium, alkynyl(aryl)iodonium, and alkyl(aryl)iodonium salts are overviewed. Application of these reagents allows mild and highly selective arylations, alkenylations, alkynylations, and alkylations of various organic and inorganic substrates in a facile and environmentally friendly manner.

Isoxazolines can be efficiently synthesized in good yields via a hypoiodite mediated catalytic oxidative cyclization of aldoximes and alkenes. This reaction involves active iodine species generated in situ from catalytic amounts of KI and Oxone.