2,2′-Biphosphinines and 2,2′-Bipyridines in Homoleptic Dianionic Group 4 Complexes and Neutral 2,2′-Biphosphinine Group 6 d6 Metal Complexes: Octahedral versus Trigonal-Prismatic Geometries

Homoleptic titanium and zirconium complexes exhibiting unusual Oiminol–metal coordination: application in stereoselective ring-opening polymerization of lactide

The synthesis and characterization of novel homoleptic Ti and Zr complexes with tridentate ONO-type Schiff base ligands and their catalytic activities towards the ring-opening polymerization (ROP) of lactide are reported.

Selective Synthesis of (Z)-Diazadiphosphafulvalene from 2,2'-bis-Azaphosphindole

The unprecedented 2,2'-bis(azaphosphindole) has been synthesized via a new route. Reaction with NaH afforded a dianion derivative 5, which is easily transformed to alkylated bis(azaphosphindole) or (Z)-P,P,N,N-cisoid diazadiphosphafulvalene. The reaction features good regioselectivity and high steroselectivity. Relatively strong fluorescence is observed with diazadiphosphafulvalenes. The X-ray crystal structure analysis showed that dianion ligand 5 is bonded to two Na atoms in a bridging cis-fashion, which allows the synthesis of diazadiphosphafulvalene in a highly stereoselective approach.

Pd(II) and Pt(II) complexes of 2-(2'-pyridyl)-4,6-diphenylphosphinine: synthesis, structure, and reactivity

The coordination chemistry of the bidentate P,N hybrid ligand 2-(2'-pyridyl)-4,6-diphenylphosphinine (1) towards Pd(II) and Pt(II) has been investigated. The molecular structures of the complexes [PdCl(2)(1)] and [PtCl(2)(1)] were determined by X-ray diffraction, representing the first crystallographically characterized λ(3)-phosphinine-Pd(II) and -Pt(II) complexes. Both complexes reacted with methanol at the P=C double bond at an elevated temperature, leading to the corresponding products [MCl(2)(1H·OCH(3))]. The molecular structure of [PdCl(2)(1H·OCH(3))] was determined crystallographically and revealed that the reaction with methanol proceeds selectively by syn addition and exclusively to one of the P=C double bonds. Strikingly, the reaction of [PdCl(2)(1H·OCH(3))] with the chelating diphosphine DPEphos at room temperature in CH(2)Cl(2) led quantitatively to [PdCl(2)(DPEphos)] and phosphinine 1 by elimination of CH(3)OH and rearomatization of the phosphorus heterocycle.

Phospha-organic chemistry: from molecules to polymers

Many parallels have been drawn between the chemistry of low-valent phosphorus and carbon. This Perspective is intended to highlight some emerging reactivity of phosphaalkenes, that is phospha-analogues of alkenes, in the areas of asymmetric catalysis and polymer science.