The N-heterocyclic carbene-ytterbium(II) amides (NHC)2Yb[N(SiMe3)2]2 (1: NHC: 1,3,4,5-tetramethylimidazo-2-ylidene (IMe4); 2: NHC: 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (IiPr)) and the NHC-stabilized rare-earth phosphide (IMe4)3Yb(PPh2)2 (3) have been synthesized and fully characterized. Complexes 1-3 are active precatalysts for the hydrophosphination of alkenes, alkynes, and dienes and exhibited much superior catalytic activity to that of the NHC-free amide (THF)2Yb[N(SiMe)2]2. Complex 1 is the most active precursor among the three complexes. In particular, complex 1 can be recycled and recovered from the reaction media after the catalytic reactions. Furthermore, it was found that complex 3 could catalyze the polymerization of styrene to yield atactic polystyrenes with low molecular weights. To the best of our knowledge, complex 1 represents the first rare-earth complex that can be recovered after catalytic reactions.

A novel protocol for effective rhodium(I)-catalyzed C-H arylation of tertiary phosphines has been devised. It is amenable to a wide range of substrates and gives the products in moderate to high yields. This strategy provides a simple and efficient route to peri-substituted (naphthalen-1-yl)phosphines.

A novel visible-light-promoted C−P bond formation reaction in the absence of both transition metal and photoredox catalysts is disclosed. By employing easily available and inexpensive heteroaryl chlorides/bromides as substrates, a variety of heteroaryl phosphine oxides were obtained in moderate to good yields. This strategy provides a simple and efficient route to heteroaryl phosphine oxides.Letter pubs.acs.org/OrgLett

Thioredoxin reductase (TrxR), which is overexpressed in many aggressive cancers, plays a crucial role in redox balance and antioxidant function, including defense of oxidative stress, control of cell proliferation, and regulation of cell apoptosis. Deactivation of TrxR can destroy the homeostasis of the cancer cells, inducing elevation of reactive oxygen species (ROS) levels and the oxidation of enzymatic substrates. Here, we synthesized and identified a new gold(I) small molecule (D9) that possesses two strong electron-donating moieties, i.e., 4-methylphenyl alkynyl and thionyldiphenyl phosphine, exhibiting an enhanced p-π conjunction effect. The resulting compound shows the increased soft Lewis acids and the stability of gold(I). And we demonstrated that D9 could efficiently and specifically inhibit the activity of TrxR in vitro and in vivo, and it could effectively avoid the ligand exchange with albumin that was one of the most abundant proteins in blood. We believe that these comprehensive studies on the relationship between the structure and performance will provide inspiring information on the precise synthesis and design of new compounds for targeting TrxR.

The well-defined NHC-copper phosphides [(NHC)CuPPh 2 ] 3 (1, NHC = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (I i Pr); 2, NHC = N,N-di-tert-butylimidazol-2-ylidene (I t Bu)) have been prepared by the reaction of simple copper halides with HPPh 2 in the presence of N-heterocyclic carbenes (NHCs). Complexes 1 and 2 enabled catalytic double hydrophosphination of alkyl and aryl terminal alkynes to yield 1,2-diphosphinoethanes selectively in good yields. On the basis of these results, the most efficient and pratical in situ CuCl 2 /NHC catalyst has been developed. It catalyzes the selective double hydrophosphination of the alkynes with high efficiency and a wide substrate scope and exhibits even better performance than the well-defined NHC-Cu phosphides. The mechanistic studies disclosed that the formation of a copper acetylide in the catalytic cycle played an important role in the acceleration of the catalytic process.