Enrique San Román (1945–2019)

An homage to the Argentinian Photochemist Enrique San Román is presented. Enrique led the Photochemistry and Chemical Kinetics research group in the Department of Inorganic, Analytical and Physical Chemistry in the Faculty of Exact and Natural Sciences of the University of Buenos Aires from 1984 until his death in July 2019. He left a strong legacy in Chemical Kinetics and Photochemistry in Argentina. He is remembered as a meticulous and very knowledgeable scientist and teacher, a loyal friend and a generous and integer human being.     

Joel Bernstein: a crystal engineer's crystal engineer

Joel Bernstein was a gentle giant in the field of organic solid‐state chemistry and a person who inspired anyone who was in his presence and attended his charismatic lectures over the five decades of his academic career. This commentary looks at his scientific publishing career.     

Recent progress of enantioseparation under scale production (2014–2019)

Very different from enantiorecognition at an analytical level, preparative enantioseparation at scale production has to confront many problems. In recent years, various separation techniques have been developed with much progress including high‐performance liquid chromatography, liquid–liquid extraction, membrane separation, enantioselective solid‐phase absorption, and enantioselective precipitation. Among them, in order to achieve high enantiomerical purity of the enantiomers after separation, two approaches are commonly carried out. One is that continuous separation is necessary when one‐step separation cannot have satisfactory efficiency. Another is that most of the research groups focus on the construction of novel chiral environment with much more rigid structures of the selectors. Combined with these two aspects, we mainly introduce current topics, trends, strategies related to enantioseparation under large scale.     

Recent developments of monolithic and open‐tubular capillary electrochromatography (2017–2019)

Capillary electrochromatography, which combined the high selectivity of high‐performance liquid chromatography and the high separation efficiency of capillary electrophoresis, is an attractive separation tool. In this review, the developments on monolithic and open tubular capillary electrochromatography during 2017 to August 2019 are summarized. Considering the development of novel stationary phases is the most active research field in capillary electrochromatography, monolithic capillary electrochromatography is classified according to the polymer‐based and hybrid monolithic columns, while open‐tubular capillary electrochromatography is categorized by cyclodextrin, silica, polymer, nanomaterials, microporous materials, and biomaterials‐based open tubular columns.     

[Bis(tetrahydrofuran–O)–bis(1,3–dialkyl–2–diphenylphosphanyl–1,3–diazaallyl)calcium] – Synthesis and Crystal Structures of Calcium Bis[phospha(III)guanidinates] and Investigations of Catalytic Activity

The reaction of [(thf)₄Ca(PPh₂)₂] ( 1 ) with diisopropyl– and dicyclohexylcarbodiimides yields the phospha(III)guanidinates [(thf)₂Ca{RNC(PPh₂)NR}₂] with R = isopropyl ( 2 ) and cyclohexyl ( 3 ). The metathesis reaction of K{RNC(PPh₂)NR} with anhydrous CaI₂ also allows the synthesis of these phospha(III)guanidinate complexes 2 and 3 . For 2 a cis arrangement is observed whereas 3 crystallizes as trans isomer. The phospha(III)guanidinates act as bidentate chelate bases with an average Ca–N distance of 242.5 pm. The C–P bond length between the PPh₂ fragment and the 1,3–diazaallyl unit is with values above 190 pm very large. The complexes 2 and 3 show a moderate catalytic activity in hydrophosphanylation reactions of dialkylcarbodiimides with diphenylphosphane.