Atom-economical synthesis of 1,2-bis(phosphine oxide)ethanes from calcium carbide with straightforward access to deuterium- and 13C-labeled bidentate phosphorus ligands and metal complexes

Straightforward access to bidentate phosphorus ligands and bis(phosphineoxide)ethanes is described based on atom-economic addition reaction. A practical approach was developed to incorporate 2H and 13C labels using easily available reagents.

Aspects of Phosphaallene Chemistry: Heat-Induced Formation of 1,2-Dihydrophosphetes by Intramolecular Nucleophilic Aromatic Substitution and Photochemical Generation of Tricyclic Phosphiranes

3H-Phosphaallenes are accessible on a new and facile route and show a fascinating chemical behavior. The thermally induced rearrangement of Mes*P═C═C(H)R' (R' = tBu, Ad) afforded by C-H activation, isobutene elimination, and C-C and P-H bond formation bicyclic 1-benzo-dihydrophosphetes (2) with PC₃ heterocycles. DFT calculations suggest a mechanism with intramolecular nucleophilic aromatic substitution and replacement of an alkyl group by the nucleophilic α-C atom of the phosphaallene. These bicycles formed W(CO)₅ complexes (3) or afforded 1,2-dihydrophosphetes with P-bound alkenyl groups by catalyst-free hydrophosphination of alkynes (4 and 5). The resulting bulky phosphines formed complexes with IrCp*Cl₂, RuCl₂, AuCl, or CuO₃SCF₃. The Ru atom is coordinated by the P atom and a phenyl group. Irradiation of TripP═C═C(H)tBu led by the insertion of the central C atom of the P═C═C group into the α-C-H bond of an iPr substituent and by C-C and P-C bond formation to a new isomer of phosphaallenes, 10, which features a strained PC₂ heterocycle. It formed adducts with M(CO)₅ (M = Cr, Mo, W) and AuCl and reacted with SO₂Cl₂ by cleavage of one of the phosphirane P-C bonds to yield PC₄ or PC₅ heterocycles. Hydrolysis yielded a PC₅ compound with a P(O)Cl group.

Stereoisomers of Pt(PL)2Cl2 derivatives – structural aspects

The coordination complexes of Pt(PL)2Cl2type (PL = monodentate P-donor ligands) cover almost 260 examples as shown by a recent survey covering the crystallographic and structural data. About 20% of these complexes exist as isomers and are summarized in this review. Included are distortion (58.5%),cis-,trans- (37.8%) and mixed isomerism (cis-,trans- and distortion) (3.7%). Distortion isomers, differing by degree of distortion in Pt-L and L-Pt-L angles, are the most common. For these derivatives the most commoncis- arranged with 31 examples and 22 examples withtrans- arranged. The complexes withcis-configuration are more distorted than theirtrans-partners, with the comprehensive values of Pt-L bond distances: 2.246 Å (P) and 2.350 Å (Cl). Such values in the complexes withtrans-configurations are 2.323 Å (P) and 2.308 Å (Cl), respectively. These are discussed with attention to anytrans-influence.