Chemistry of π-complexes derived from [(Ph3P)2Pt(η3-CH2CCPh)](O3SCF3). Interconversion between η3-alkoxoallyl and η3-oxoallyl complexes and between η3-aminoallyl and η3-iminoallyl complexes

A study is reported on the synthesis, spectroscopic properties, molecular structure, and reaction chemistry of η3-propargyl/allenyl complexes of platinum and palladium of the type [(PPh3)2M(η3-CH2CCR)]+ (M = Pt, R = Ph (1a), Me (1b); M = Pd, R = Ph (2a), Me (2b)). Complexes 1a,b were obtained by each of the following methods: (i) reaction of trans-(PPh3)2PtBr(η1-CH2C⋮CPh) with AgO3SCF3; (ii) treatment of (PPh3)2Pt(η2-PhC⋮CCH2OMe) with BF3·OEt2; (iii) addition of RC⋮CCH2OS(O)2C6H4Me-p to (PPh3)2Pt(η2-C2H4) in solution. Complexes 2a,b resulted upon (i) abstraction of Br- from trans-(PPh3)2PdBr(η1-CH2C⋮CR)/trans-(PPh3)2PdBr(η1-C(R)CCH2) with AgBF4 and (ii) treatment of Pd2(dba)3·CHCl3 with PPh3 and RC⋮CCH2OS(O)2C6H4Me-p. The structures of 1a(OTf)·CH2Cl2 (Tf = O2SCF3) and 2a(BF4) were determined by X-ray diffraction techniques. Both cationic metal complexes show remarkably similar structures, the salient features being the attachment to the metal of all three propargyl/allenyl carbon atoms of the nonlinear C3 fragment (C(1)−C(2)−C(3) bond angles: 152.2(9)° for 1a, 154.7(5)° for 2a) and the essentially coplanar arrangement of the three carbon, two phosphorus, and platinum or palladium atoms. 1a,b react readily with MeOH and Et2NH to afford the corresponding complexes [(PPh3)2Pt(η3-CH2C(X)CHR)]+ (X = OMe, NEt2); 2a,b behave analogously, except that the reaction with MeOH requires trace amounts of NaOMe or NEt3. 1H and 13C NMR spectroscopic data suggest that the reaction products are best formulated as resonance hybrids of η3-allyl and metallacyclic structures.

show abstract

“…All are stable to air in the solid. 2a,b do not appear to be affected by moisture, whereas 1a slowly reacts with water in the air …”

Section: Resultsmentioning

confidence: 99%

η³-Propargyl/Allenyl Complexes of Platinum and Palladium of the Type [(PPh₃)₂M(η³-CH₂CCR)]⁺

et al. 1996

Self Cite

View full text Add to dashboard Cite

show abstract

“…Parallel work in the laboratories of Wojcicki and Chen explored the conversion of η 3 -propargyl platinum complexes to η 3 -trimethylenemethane complexes . The addition of sodium dimethylmalonate to palladium and platinum 48 η 3 -propargyl complexes produced η 3 -trimethylenemethane (η 3 -TMM) complexes (Scheme ).…”

Section: Discussionmentioning

confidence: 99%

Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Casey

Nash

et al. 1998

J. Am. Chem. Soc.

View full text Add to dashboard Cite

Kinetic addition of nucleophiles occurs at the center carbon of η3-propargyl rhenium complexes to produce rhenacyclobutenes. Reaction of P(CH3)3 with C5Me5(CO)2Re[η3-CH2C⋮CC(CH3)3]+BF4 - (3a) gave the metallacyclobutene C5Me5(CO)2ReCH2C(PMe3)CC(CH3)3 +BF4 - (4a), which was characterized by X-ray crystallography. Malonate and acetylide nucleophiles reacted with C5Me5(CO)2Re[η3-CH2C⋮CCH3]+PF6 - (3b) to give metallacyclobutene complexes. Pyridine added to the central propargyl carbon of 3b at low temperature to produce the metastable metallacyclobutene C5Me5(CO)2ReCH2C(NC5H5)CCH3 +PF6 - (14b) which rearranged to the η2-allene complex C5Me5(CO)2Re[η2-H2CCC(NC5H5)CH3]+PF6 - (15K) at room temperature. 4-(Dimethylamino)pyridine (DMAP) added to the central carbon of the tert-butyl-substituted η3-propargyl complex 3a below −38 °C to give the rhenacyclobutene complex C5Me5(CO)2ReCH2C(NC5H4NMe2)CC(CH3)3 +BF4 - (22a) which rearranged to the η2-alkyne complex C5Me5(CO)2Re[η2-(CH3)3CC⋮CCH2NC5H4NMe2]+BF4 - (23) at room temperature. Reaction of water with C5Me5(CO)2Re[η3-CH2C⋮CH]+BF4 - (3c) gave the hydroxyallyl complex C5Me5(CO)2Re[η3-CH2C(OH)CH2]+BF4 - (29) by a process proposed to involve nucleophilic addition of water to the central propargyl carbon of 3c followed by protonation of the metallacyclobutene intermediate.

show abstract

“…Such a reactivity again supports the notion that the formation of metallacyclobutenes likely is due to external nucleophilic attack at the central carbon of an η 3 -allenyl/propargyl ligand (Scheme ). Metallacyclobutenes have been invoked as the kinetic intermediates of the formation of central-carbon-substituted η 3 -allyl complexes from nucleophilic addition of η 1 -allenyl and η 3 -allenyl/propargyl complexes. − , A reaction resulting in the formation of {Pt(PPh 3 ) 2 [η 3 -CH 2 C(PPh 3 )CH 2 ]}(BF 4 ) 2 ( 7 ) from protonation of 2b affords sound evidence for the former pathway (Scheme ). On the other hand, insertion of coordinated allene into an M−L bond also was considered to be a possibility …”

Section: Resultsmentioning

confidence: 99%

“…A new synthetic route, the addition of soft nucleophiles to a cationic η 3 -allenyl/propargyl rhenium complex to give a rhenacyclobutene complex, was reported by Casey and co-workers . We and others have independently developed the addition reactions of cationic η 3 -allenyl/propargyl complexes of the late transition metals as a route to central-carbon-substituted η 3 -allyl complexes, η 3 -trimethylenemethane complexes, and η 3 -oxa- and η 3 -azatrimethylenemethane complexes )…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Metallacyclobutenes of Late Transition Metals via Nucleophilic Addition of Allenyl or Propargyl Complexes

et al. 1998

View full text Add to dashboard Cite

The regioselective addition of NEt3, PPh3, or pyridine to the central carbon of a cationic η3-allenyl/propargyl complex of platinum, {Pt(PPh3)2(η3-C3H3)}(BF4) (1), leads to the formation of the new cationic = NEt3 (2a), PPh3 (2b), C5H5N (2c)) via formation of a C−N or C−P bond, respectively. Complex 2c can transform into {cis-Pt(PPh3)2(Py)(η1-CHCCH2)}(BF4) (3). The reverse reaction has not been observed. It is suggested that nucleophilic addition of 1 likely involves external attack at the central carbon of the η3-allenyl/propargyl ligand. Protonation of 2b yields {Pt(PPh3)2[η3-CH2C(PPh3)CH2]}(BF4)2 (7). Addition of PPh3 to a labile η1-allenyliridium complex, (OC-6-42)-Ir(Cl)(PPh3)2(OTf)(CO)(η1-CHCCH2) (4), results in the The single-crystal X-ray structure of 5 has been determined.

show abstract

Chemistry of π-complexes derived from [(Ph3P)2Pt(η3-CH2CCPh)](O3SCF3). Interconversion between η3-alkoxoallyl and η3-oxoallyl complexes and between η3-aminoallyl and η3-iminoallyl complexes

Cited by 19 publications

References 12 publications

η³-Propargyl/Allenyl Complexes of Platinum and Palladium of the Type [(PPh₃)₂M(η³-CH₂CCR)]⁺

η³-Propargyl/Allenyl Complexes of Platinum and Palladium of the Type [(PPh₃)₂M(η³-CH₂CCR)]⁺

Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Synthesis of Metallacyclobutenes of Late Transition Metals via Nucleophilic Addition of Allenyl or Propargyl Complexes

Contact Info

Product

Resources

About

Chemistry of π-complexes derived from [(Ph3P)2Pt(η3-CH2CCPh)](O3SCF3). Interconversion between η3-alkoxoallyl and η3-oxoallyl complexes and between η3-aminoallyl and η3-iminoallyl complexes

Cited by 19 publications

References 12 publications

η3-Propargyl/Allenyl Complexes of Platinum and Palladium of the Type [(PPh3)2M(η3-CH2CCR)]+

η3-Propargyl/Allenyl Complexes of Platinum and Palladium of the Type [(PPh3)2M(η3-CH2CCR)]+

Kinetic Addition of Nucleophiles to η3-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Synthesis of Metallacyclobutenes of Late Transition Metals via Nucleophilic Addition of Allenyl or Propargyl Complexes

Contact Info

Product

Resources

About

η³-Propargyl/Allenyl Complexes of Platinum and Palladium of the Type [(PPh₃)₂M(η³-CH₂CCR)]⁺

η³-Propargyl/Allenyl Complexes of Platinum and Palladium of the Type [(PPh₃)₂M(η³-CH₂CCR)]⁺

Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes