cis-Bis(alkenyl)iridium(III) Compounds by Apparent Insertion of Two Acetylenes into Two Ir−P Bonds:  Crystal Structures of cis,trans-[IrCl(−CHCH⁺PPh₃)₂(CO)(PPh₃)₂]²⁺ and [Ir(OClO₃)(CH₃)(H₂O)(CO)(PPh₃)₂]⁺

Abstract

cis-Bis(alkenyl)iridium complexes cis,trans-[IrR(-CHdCH, CH 3 (b), Cl (c)) have been prepared from the reactions of dihaloiridium(III) compounds with HCtCH and PPh 3 . Reactions of 2b and 2c with CH 2 dCHCH 2 Br give bis(alkenyl)-(PPh 3 )iridium, cis-[IrBr(CH 3 )(-CHdCH + PPh 3 ) 2 (CO)(PPh 3 )] + , and cis,cis-[IrBr 2 (-CHdCH-+PPh 3 ) 2 (CO)(PPh 3 )] + . Crystal structures of 2c and [Ir(OClO 3 )(CH 3 )(H 2 O)(CO)(PPh 3 ) 2 ] + (4) have been determined by X-ray diffraction data analysis.Attempts to mount crystals of 2a and 2b on a X-ray diffractometer have failed due to the collapse of the

Regioselective Cis Insertion of DMAD into Au–P Bonds: Effect of Auxiliary Ligands on the Reaction Mechanism

“…For the insertion of alkynes into M–P bonds, a number of trans insertions, which proceed through nucleophilic attack on the coordinated alkyne by the phosphine, have been reported . Conversely, cis insertion is quite rare; to our knowledge, insertion into a Pd complex with a strained bidentate ligand and a recent report with Au­[Si­( t -Bu)­(Ph) 2 ]­(PPh 3 ) ( 11 ) are the only examples. , For the mechanism of the insertion reaction of 2 into the Au–P bond of 11 , it was proposed that the insertion took place through the dissociation of PPh 3 , Michael addition of PPh 3 to 2 to afford zwitterionic intermediate 12 , and finally nucleophilic attack on the Au–Si fragment to afford 13 .…”

Zwitterionic Ammoniumalkenyl Ligands in Metal Cluster Complexes. Synthesis, Structures, and Transformations of Zwitterionic Trimethylammoniumalkenyl Ligands in Hexaruthenium Carbido Carbonyl Complexes

“…Most examples of these species contain the phosphonium grouping. Some examples of these are E , F , and G , and all of these have been isolated only as ligands in complexes containing one or more metal atoms. − Complexes containing the zwitterionic phosphoniumalkenyl ligands E are the most abundant . Metal complexes containing zwitterionic ammoniumalkenyl ligands, such as H , are quite rare …”

Competing C–H and C–F bond activation reactions of a fluorinated olefin at Rh: a fluorido vinylidene complex as an intermediate in an unprecedented dehydrofluorination step

“…NMR spectrum for the vinyl proton at d 6.68 ppm reveals a 36 Hz coupling to the phosphonio moiety, which is typical for a cis substitution, 55,59,60 a 6 Hz coupling to the CF 3 group which is typical for the geminal arrangement, 24,25,29 and 3 Hz coupling to rhodium and the phosphine ligands.…”

“…Phosphonioalkenyl complexes are commonly obtained by nucleophilic addition of a phosphine to a h 2 -coordinated alkyne. [59][60][61][62] Other methodologies such as nucleophilic substitution of a uorine atom at the b-position of a vinyl ligand 63 or nucleophilic attack at the a-position of a vinylidene ligand have been scarcely reported. 55 Noteworthy, only in the latter case the phosphonio moiety is bonded to the a-carbon.…”