NMR studies on the novel heterobimetallic complexes [M(dppm)(Ph2PCH2PPh2PPPP) {Pt(PPh3)2}]OTf (M = Rh, Ir) derived from the stepwise activation of white phosphorus

Abstract

The solution structures of the novel heterobimetallic complexes [Ir(dppm)(Ph(2)PCH(2)PPh(2)PPPP){Pt(PPh(3))2}]OTf and [Rh(dppm)(Ph(2)PCH(2)PPh(2)PPPP){Pt(PPh(3))(2)}]OTf derived from the reaction of Rh and Ir--P(5) precursors with [Pt(C2H4)(PPh3)2] have been unambiguously assigned on the basis of 1H NMR and 31P{1H} NMR data. The results are in agreement with the regio-selective insertion of the {Pt(PPh3)2} moiety resulting in a new pentaphosphorus topology which agrees with the formal formation of a unique phosphonium(+)-tetraphosphabutadienide(2-) ligand.

Stabilization of the Triphosphallyl Ligand η3‐P3{P(O)H} at Iridium via Alkaline Activation of P4

“…Starting parameters were refined by using iterative methods to obtain the best fit values of chemical shifts, line broadness, and J coupling constants. Previous results on comparable metal-phosphine complexes bearing polyphosphorus units [3,10] allowed to distinguish between strong ( Table 2). …”

“…[10] Based on these previous results, we decided to explore the reactivity of the pentaphosphorus moiety in 1 in the presence of other reagents, including water. In this respect, it is well known that some mono-and bimetallic ruthenium [11] and osmium [12] complexes coordinating P 4 can undergo mild hydrolysis giving a variety of polyphosphorus products according to the reaction conditions.…”

P4 Activation by Late-Transition Metal Complexes

“…Thus, complexes 284 and 285 can be activated electrochemically by irreversible transfer of two electrons or by interaction with nucleophiles by reaction with [Pt(C 2 H 4 )(PPh 3 ) 2 ], as clearly identified by 1 H and 31 P{ 1 H} NMR experiments . Regioselective insertion of the {Pt(PPh 3 ) 2 } moiety into one of the P−P edges of the P 5 unit in DCM at −40 °C results in the formation of the novel heterobimetallic complexes [Rh(dppm)(Ph 2 PCH 2 PPh 2 PPPP){Pt(PPh 3 ) 2 }]OTf ( 288 ) and [Ir(dppm)(Ph 2 PCH 2 PPh 2 PPPP){Pt(PPh 3 ) 2 }]OTf ( 289 ).…”

“…In most instances, such heterodinuclear compounds have been already mentioned in the appropriate sections related to each specific metal. Examples of such species are [{(triphos)Ni(μ,η 3:2 - cyclo- P 3 )}{Pt(PPh 3 ) 2 }] + ( 176 ), [Co(μ,η 1:2:1 - PP −PPh 2 CH 2 PPh 2 ) 2 {Pt(PPh 3 ) 2 }]BF 4 ( 185 ), [M(dppm)(Ph 2 PCH 2 PPh 2 PPPP){Pt(PPh 3 ) 2 }]OTf [M = Rh ( 288 ), Ir ( 289 )] and the related [{(triphos)Co} 2 (μ 3 ,η 3:3:3 -P 6 H 2 ){Pt(PPh 3 ) 2 }](OTf) 2 ( 177 ) where one PPh 3 ligand has been additionally replaced by the PtL 2 fragment …”

The Bimetallic Activation of White Phosphorus by trans‐[RhCl(CO)(dppm)]2 Results in a Tetrahedro‐Rh2P2 Moiety

“…Rhodium and iridium monocationic complexes [M(dppm) 2 ][OTf] also activate P 4 , giving complexes such as [M(dppm)(PPh 2 CH 2 PPh 2 PPPP)] + [M = Ir, 2a ; Rh, 2b ] by following a bimetallic activation pathway, with P 4 bridging two metal centres in an η 2 ‐fashion during an intermediate reaction step 4. The P 4 moiety of 2a and 2b may be further activated by reaction of these complexes with a Pt 0 precursor through cleavage of a P–P bond and coordination to Pt, resulting in the formation of new heterobimetallic complexes [M(dppm)(Ph 2 PCH 2 PPh 2 PPPP){Pt(PPh 3 ) 2 }]OTf {M = Ir ( 3a ), Rh ( 3b )} 5. A bimetallic activation pathway is also responsible for the hydrolysis of P 4 , affording a variety of polyphosphanes6 and hydroxyphosphanes7 stabilised by {CpRu(PPh 3 ) 2 } moieties.…”