Crystallization-induced emission enhancement was achieved in metal nanoclusters for the first time.

No abstract

An azaborine-based phosphine-Pd catalystw as introduced by the Liu group to promote trans hydroboration of the C Ct riple bond of internal 1,3-enyne substrates. Despite the excellent yield and selectivity observed experimentally,t he mechanism and the origin of this special trans selectivity remained unknown. Herein, ac omprehensive theoretical investigation was performed to clarify these issues. Accordingly,t wo main mechanisms (inner-and outersphere) were proposed and examined. Different from the conventionali nner-sphere mechanism,i nw hich the transition metal is involved in HÀBb ond cleavage, this reaction follows an outer-sphere mechanism, in which Pd does not directlyp articipate in HÀBb ond cleavage. More specifically, the favorable pathway followed aT suji-Trost type reaction, in which the HÀBb ond was weakened by the formation of a four-coordinate boron intermediate (i.e.,t he boron is attached to the terminalc arbon of the alkyne group). It then underwent ah ydride-transfer process with the assistance of as econd borane molecule, and finally reductivee limination generated the trans hydroboration product. Further analysis ascribed the origin of the special trans selectivity to the unique steric effect and electronic effect introduced by the special k 1 -P-h 2 -BC coordinationpattern.

The presence of 1,1′-bis-(diphenylphosphino)ferrocene ligands and ensemble effects in novel nanoclusters M1Ag21(dppf)3(SAdm)12 (M = Au/Ag) provide excellent ORR performances.