Synthesis of New Late Transition Metal P,P-, P,N-, and P,O- Complexes Using Phosphonium Dimers as Convenient Ligand Precursors

Abstract

Always cite the published version, so the author(s) will receive recognition through services that track citation counts, e.g. Scopus. If you need to cite the page number of the author manuscript from TSpace because you cannot access the published version, then cite the TSpace version in addition to the published version using the permanent URI (handle) found on the record page. ABSTRACTThe phosphonium dimer [-Cy2PCH(OH)CH2-]2(X)2, X = Cl -, Brwas used to synthesize and characterize a variety of late transition metal complexes containing chelating phosphino-enolate (PCy2CH=CHO -), imine (PCy2CH2CH=NR, R = Ph, (S)-CHMePh), and oxime (PCy2CH2CH=NOH) ligands. The phosphonium dimer, when deprotected with base, generates the phosphine aldehyde PCy2CH2CHO in situ, which, in the presence of [M(COD)Cl]2, M = Rh, Ir, and a PF6salt, or [Ni(H2O)6][BF4]2, facilitates a condensation reaction with an amine or hydroxylamine to form phosphino-imine or phosphino-oxime metal complexes [M(COD)(P-N)][PF6] or [Ni(P-N)2][X]2, X = ClO4 -, BF4 -, respectively. In the absence of an amine, phosphino-enolate containing complexes are formed. A neutral Ni(II) complex Ni(PCy2CH=CHO)2 with trans-bis(phosphino-enolate) ligands which resemble ligands used on nickel for olefin oligomerization, as well as neutral Rh(I) and Ir(I) 1,5-cyclooctadiene complexes M(COD)(PCy2CH=CHO) are characterized. Both the rhodium and iridium complexes are active olefin hydrogenation catalysts. Reaction of the phosphino-aldehyde with Pt(COD)Cl2 results in the formation of trans-PtCl2(PCy2CH2CHO)2 with pendant aldehyde groups and under certain conditions, they undergo an intraligand aldol condensation to form a diphosphine ligand.

Palladium(ii) complexes with a phosphino-oxime ligand: synthesis, structure and applications to the catalytic rearrangement and dehydration of aldoximes

“…26 This fact together with the limitations found with other previously described palladium catalysts make complex 1 an appealing option for future practical applications. (2). In addition, we have also demonstrated the utility of these species in catalysis.…”

“…2; R 1 = OH, R 2 = Me) is also briefly discussed. (2) was isolated as an air-stable yellow solid in 82% yield (Scheme 2), and its structure fully confirmed by X-ray diffraction methods (see ESI). Alternatively, this compound could also be obtained in similar yield from the reaction of 1 with one equivalent of 2-Ph 2 PC 6 H 4 CH=NOH (Scheme 2).…”

“…Indeed, the first, and only examples, of metal complexes containing a coordinated phosphino-oxime, namely [M(COD){κ 2 (P,N)-Cy 2 PCH 2 CH=NOH}][PF 6 ] (A in Fig. 1), have been described very recently by Morris and co-workers.…”

“…1), have been described very recently by Morris and co-workers. 2 In addition to complexes A, which showed a modest activity in the catalytic hydrogenation of cyclooctene, the phosphino-aldoximes B and their oxides C were also employed by Wan and co-workers as auxiliary ligands in copper-catalyzed arylation reactions of amines 3 and thiols, 4 as well as in palladium-catalyzed SuzukiMiyaura cross-coupling processes. 5 However, no well-defined metal complexes could be isolated in these cases.…”

Platinum Complexes with a Phosphino‐Oxime/Oximate Ligand

“…In marked contrast, little is known about the chemistry of the related phosphino‐oxime derivative 1 (Figure ), a rather surprising fact given the commercial availability of this compound and the presence in its structure of a non‐innocent hydroxyl functionality . Thus, the deprotonation of this OH group would allow the generation of the corresponding oximate anion, thereby conferring to 1 a greater coordination versatility compared to compounds A .…”