κ³(P,C,C)-Allylphosphane Iridium(III) and Rhodium(III) Complexes: Preparation and Reactivity toward Nucleophilic Reagents

Abstract

The first allylphosphane iridium complexes [IrCl2(η5-C5Me5)­{κ­(P)-R2PCH2CHCH2}] (R = iPr (1a), Ph (1b)) have been synthesized by the reaction of the dimeric complex [IrCl­(μ-Cl)­(η5-C5Me5)]2 with allyldiisopropylphosphane (ADIP) and allyldiphenylphosphane (ADPP), respectively. The cationic complex [IrCl­(η5-C5Me5)­{κ3(P,C,C)-iPr2PCH2CHCH2}]+ (3 + ) has been prepared by the reaction of complex 1a with NaX (X = BPh4, PF6) in dichloromethane. The complex 3+ reacts with phosphanes and alkanethiolates to give the uncommon cationic complexes [IrCl­(η5-C5Me5)­{κ2(P,C)-iPr2PCH2CH­(PR2R′)­CH2}]+ (5 + –7 +) and IrCl­(η5-C5Me5)­{κ3(P,C,S)-iPr2PCH2CH­(SR)­CH2}]+ (13 + and 14 + ) by chemo- and regioselective addition of the nucleophiles to the π-olefin system. The reaction of 1a with LiBHEt3 gives the neutral complex [IrCl­(η5-C5Me5)­{κ2(P,C)-iPr2PCH2CH2CH2}] (10). For comparative purposes, the synthesis of the complex [RhCl­(η5-C5Me5)­{κ3(P,C,C)-iPr2PCH2CHCH2}]+ (4 + ) and its reactivity with phosphanes, hydride, and thiolates has been also assayed.

Reactivity of κ(P)‐Alkenylphosphane Rhodium(III) and Iridium(III) Complexes toward Nucleophilic Reagents

“…The complexes 1, 3 a,b, and 4 a,b ( Figure 1) [9] On the other hand, the homoallyldiphenylphosphane complex [RhCl 2 (h 5 -C 5 Me 5 ){k(P)-Ph 2 P(CH 2 ) 2 CH=CH 2 }] (1) has been synthesized in 85 % yield by treatment of the dimeric complex [{RhCl(m-Cl)(h 5 -C 5 Me 5 )} 2 ] with homoallyldiphenylphosphane (HADPP) in dichloromethane at room temperature. This complex is readily transformed into the corresponding k 3 (P,C,C) derivative [RhCl(h 5 -C 5 Me 5 ){k 3 (P,C,C)-Ph 2 P(CH 2 ) 2 CH=CH 2 }][BPh 4 ] (2) (91 %) by chloride abstraction with NaBPh 4 (Scheme 1).…”

“…[3d] Recently, we reported the first synthesis of allylphosphane iridium complexes of the type k(P) and k(P,C,C) [IrCl 2 (h 5 -C 5 Me 5 ){k(P)-R 2 PCH 2 CH=CH 2 }] (R = iPr, Ph) and [IrCl(h 5 -C 5 Me 5 ){k 3 (P,C,C)-iPr 2 PCH 2 CH=CH 2 }] + as well as the preparation of the new rhodium complexes [RhCl 2 (h 5 -C 5 Me 5 ){k(P)-iPr 2 PCH 2 CH=CH 2 }] and [RhCl(h 5 -C 5 Me 5 ){k 3 (P,C,C)-iPr 2 PCH 2 CH=CH 2 }] + . [9] The behavior of these k 3 (P,C,C) complexes toward neutral (phosphanes) and anionic (NaSR) nucleophiles leading to very uncommon k 2 (P,C) and k 3 (P,C,S) complexes has been also studied in our group. [9] Continuing with these studies, we report in this paper on the reactivity of k(P)-alkenylphosphanes (allyldiphenylphosphane (ADPP), allyldiisopropylphosphane (ADIP) and homoallyldiphenylphosphane (HADPP)) rhodium and iridium complexes with various nucleophilic reagents.…”

“…[9] The behavior of these k 3 (P,C,C) complexes toward neutral (phosphanes) and anionic (NaSR) nucleophiles leading to very uncommon k 2 (P,C) and k 3 (P,C,S) complexes has been also studied in our group. [9] Continuing with these studies, we report in this paper on the reactivity of k(P)-alkenylphosphanes (allyldiphenylphosphane (ADPP), allyldiisopropylphosphane (ADIP) and homoallyldiphenylphosphane (HADPP)) rhodium and iridium complexes with various nucleophilic reagents. Depending on the metal and the nature of the nucleophile, either metalligand exchange or addition to the C=C moiety is observed.…”

Isomerization Processes on Organoruthenium Complexes Bearing κ2(P,C)‐Bidentate Ligands Generated Through Nucleophilic Addition to Coordinated Alkenyl Phosphanes

“…These isomerization processes have been also detected for rhodium and iridium complexes [MCl(η 5 ‐C 5 Me 5 ){ĸ 2 ( P , C )‐ i Pr 2 PCH 2 CH(PPh 3 )CH 2 }][BPh 4 ] …”

“…These isomerization processes have been also detected for rhodium and iridium complexes [MCl(η 5 -C 5 Me 5 ){ĸ 2 (P,C)-iPr 2 PCH 2 CH(PPh 3 )CH 2 }][BPh 4 ]. [18] The mechanism proposed for these rhodium and iridium complexes starts with a -H elimination to give a metal hydride which would insert into the alkene to give the thermodynamic product. Even when this mechanism can be proposed for our complexes (Scheme 6, pathway A), we cannot rule out the opening of the ruthenaphosphacycle (Scheme 6, pathway B).…”