Rainer Feser

Basische metalle XXXVI. Die synthese stabiler hydrido(olefin)rhodium-komplexe und von [C5H5Rh(PMe3)(η3-CH3CHC6H5)]PF6

Summary The complexes C 5 H 5 Rh(PMe 3 )C 2 H 3 R′ (R′ = H, Me, Ph) and C 5 H 5 Rh(PR 3 )-C 2 H 4 (PR 3 = PMe 2 Ph, PPr 3 i ) are prepared by reaction of [PMe 3 (C 2 H 3 R′)RhCl] 2 or [PR 3 (C 2 H 4 )RhCl] 2 and TlC 5 H 5 , respectively. They react with HBF 4 in ether/ propionic anhydride to form the BF 4 salts of the hydrido(olefin)rhodium cations [C 5 H 5 RhH(C 2 H 3 R′)PR 3 ] + (R = Me; R′ = H, Me and R = Pr i ; R′ = H). From C 5 H 5 Rh(PMe 3 )C 2 H 3 Ph and CF 3 COOH/NH 4 PF 6 the η 3 -benzyl complex [C 5 H 5 Rh(PMe 3 )(η 3 -CH 3 CHC 6 H 5 )]PF 6 is obtained. The reversibility of the protonation reactions is demonstrated by temperature-dependent NMR spectra and by deuteration experiments. The complexes C 5 H 5 Rh(PMe 3 )C 2 H 3 R′ (R′ = H, Ph) and C 5 H 5 Rh(PMe 2 Ph)C 2 H 4 react with CH 3 I in ether to give the salts [C 5 H 5 RhCH 3 (C 2 H 3 R′)PR 3 ]I which in THF or CH 3 NO 2 yield the neutral compounds C 5 H 5 RhCH 3 (PR 3 )I.

Basische metalle : XXXVII. Zur reaktivität der ethylen(hydrido)rhodium-komplexe [C5H5RhH(C2H4)PR3]X gegenüber nucleophilen: insertion versus substitution

Abstract The complex [C 5 H 5 RhH(C 2 H 4 )PMe 3 ]BF 4 (I) reacts with NaF and NaCN by deprotonation to give C 5 H 5 Rh(PMe 3 )C 2 H 4 but with NaCl, NaBr and NaI the ethylrhodium compounds C 5 H 5 RhC 2 H 5 (PMe 3 )X (II–IV) are obtained. The reactions of I with CO and PPr i 3 yield the BF 4 salts of the cations [C 5 H 5 RhH(CO)PMe 3 ] + and [C 5 H 5 RhH(PPr i 3 )PMe 3 ] + (V, VI), respectively, from which the uncharged complexes C 5 H 5 Rh(CO)PMe 3 (VII) and C 5 H 5 Rh(PPR i 3 )PMe 3 (VIII) are prepared. The carbonyl compound VII is also accessible either from C 5 H 5 Rh(CO) 2 and PMe 3 or from C 5 H 5 Rh(PMe 3 ) 2 and CO. The reaction of I with ethylene leads to the BF 4 salt of the cation [C 5 H 5 RhC 2 H 5 (PMe 3 )C 2 H 4 ] + (X) which on treatment with PMe 3 forms the complex [C 5 H 5 RhC 2 H 5 (PMe 3 )C 2 H 4 PMe 3 ]BF 4 (XI). The compound [C 5 H 5 RhH(C 2 H 4 )PPr i 3 ]BF 4 (XII) reacts with NaI by insertion to yield C 5 H 5 RhC 2 H 5 (PPr i 3 )I (XIII) whereas with PPr i 3 the salt [C 5 H 5 RhH(PPr i 3 ) 2 ]BF 4 (XIV) is produced. The bis(triisopropylphosphine) complex C 5 H 5 Rh(PPr i 3 ) 2 (XVI) is obtained from XIV and NaH.

Basische metalle: XLIX. Halbsandwichverbindungen des typs C5H5RhL2 und C5H5RhLL′ als synthesebausteine für carbenoid- und ylidrhodium(III)-komplexe

Abstract Half-sandwich type compounds C 5 H 5 RhLL′ (L= PMe 3 , L′= PR 3 , P(OR′) 3 ; L = PR 3 , L′ = P(OMe) 3 ; L = C 2 H 4 , L′ = P(OMe) 3 , SMe 2 ; L = L′ = CNR) are prepared starting from [(C 8 H 14 ) 2 RhCl] 2 and [(C 2 H 4 ) 2 RhCl] 2 by stepwise displacement of the olefinic ligands and final cleavage of the chloride bridges with NaC 5 H 5 . The compounds C 5 H 5 RhL 2 and C 5 H 5 RhLL′ react with CH 2 I 2 form the carbenoid-rhodium(III) complexes C 5 H 5 RhCH 2 I(L)I and [C 5 H 5 RhCH 2 I(L)L′] + , the latter being isolated as the BF 4 or PF 6 salts. For L′ = P(OR) 3 (R = Me, Et), successive reaction with NaI gives the dialkylphosphonate compounds C 5 H 5 RhCH 2 I(L)P(O)(OR) 2 . The carbenoid complexes [C 5 H 3 RhCH 2 I(PMe 3 ) 2 ]X and [C 5 H 5 RhCH 2 I(PR 3 )L]PF 6 isomerize thermally or on addition of NEt 3 to produce the yliderhodium(III) compounds [C 5 H 5 Rh(CH 2 PMe 3 )(PMe 3 )I]PF 6 and [C 5 H 5 Rh(CH 2 PR 3 )(L)I]PF 6 , respectively. In all cases, the ligand with the strongest donor properties migrates from the metal to the carbon. Kinetic studies of the reaction of [C 5 H 5 RhCH 2 I(PMe 3 )P(OMe) 3 ]PF 6 to give [C 5 H 5 Rh(CH 2 PMe 3 )(P(OMe) 3 )I]PF 6 show a distinct dependence of the isomerization rate on the NEt 3 concentration and suggest an intramolecular exchange mechanism similar to that of dyotropic rearrangements. Substitution of the carbon-bonded iodide in [C 5 H 5 RhCH 2 I(PMe 3 ) 2 ]I and C 5 H 5 RhCH 2 I(PMe 3 )P(O)(OMe) 2 leads to the formation of the ylide complexes [C 5 H 5 Rh(CH 2 PMe 3 )(PMe 3 ) 2 ]I 2 and [C 5 H 5 Rh(CH 2 L)(PMe 3 )P(O)(OMe) 2 ]I. The syntheses of the compounds [C 5 H 5 RhCH 2 X(PMe 3 ) 2 ]PF 6 (X = Cl, CN), [C 5 H 5 RhCH 2 X(PMe 3 )P(OMe) 3 ]PF 6 (X = Cl, Br), [C 5 H 5 Rh(CH 2 PMe 3 )(PMe 3 )Br]PF 6 , C 5 H 5 RhCH 3 (PMe 3 )P(O)(OMe) 2 and C 5 H 5 RhCH 3 (PMe 3 )P(O)(OMe) 2 · NaI are also described.

Basische metalle : XXXV. Neutrale rhodium-carbenoid-verbindungen und ihre umwandlung in kationische und neutrale rhodium-ylid-komplexe☆

Abstract The reaction of C 5 H 5 Rh(PMe 3 )C 2 H 4 or C 5 H 5 Rh(PMe 3 )CO with CH 2 I 2 affords the compound C 5 H 5 RhCH 2 I(PMe 3 )I from which stable cationic ylide-rhodium complexes [C 5 H 5 RhCH 2 L(PMe 3 )I]X (L = PPh 3 , PPr i 3 , AsPh 3 , SMe 2 , NEt 3 ; X = I, PF 6 ) are prepared. In the presence of NEt 3 , C 5 H 5 RhCH 2 I(PMe 3 )I also undergoes isomerisation to yield C 5 H 5 Rh(CH 2 PMe 3 )I 2 . C 5 H 5 RhCH 2 I(PMe 3 )I reacts with NaOMe and NaSMe to give C 5 H 5 RhCH 2 OMe(PMe 3 )I and C 5 H 5 RhCH 2 SMe(PMe 3 )SMe, respectively.

Synthese und elektrophilie kationischer ethylenrhodium-komplexe☆

Abstract The reaction of [C 5 H 5 Rh(PMe 3 ) 2 C 2 H 5 ]I with excess [CPh 3 ]BF 4 gives the ethylene complex [C 5 H 5 Rh(PMe 3 ) 2 C 2 H 4 ](BF 4 ) 2 (VIII) in high yield. By using the partially deuterated compound [C 5 H 5 Rh(PMe 3 ) 2 CH 2 CD 3 ]PF 6 as starting material it has been proved that hydride abstraction from the β-carbon atom of the ethyl group occurs. VIII reacts with NEt 3 , PMe 3 , PPr 3 i , PPh 3 and P(OMe) 3 by nucleophilic addition at the ethylene and formation of the β-substituted ethylrhodium complexes [C 5 H 5 Rh(PMe 3 ) 2 C 2 H 4 Nu](BF 4 ) 2 (XI–XV). In presence of NaI, compound XV (Nu = P(OMe) 3 ) undergoes a Michaelis-Arbuzov-type reaction to form [C 5 H 5 Rh(PMe 3 ) 2 C 2 H 4 P(O)(OMe) 2 ]BF 4 . Reaction of VIII with anionic nucleophiles X − leads to either nucleophilic addition or olefin displacement or both. The electrophilic behaviour of the monocationic ethylene complex [C 5 H 5 RhCH 3 (C 2 H 4 )P(OMe) 3 ] + has also been investigated. The PF 6 salt reacts nearly quantitatively with PMe 3 and P(OMe) 3 to give the compounds [C 5 H 5 RhCH 3 (C 2 H 4 Nu)P(OMe) 3 ]PF 6 (XXIII, XXIVb) whereas the iodide on reaction with P(OMe) 3 produces the neutral complex C 5 H 5 RhCH 3 [C 2 H 4 P(O)(OMe) 2 ]P(OMe) 3 . Attempts to obtain a dinuclear Rh(μ-C 2 H 4 )Rh bridged compound by addition of the metal base C 5 H 5 Rh(PMe 3 ) 2 to the ethylene ligand of [C 5 H 5 RhCH 3 (C 2 H 4 )P(OMe) 3 ]PF 6 surprisingly led to complete methyl group transfer and formation of [C 5 H 5 Rh(PMe 3 ) 2 CH 3 ]PF 6 and C 5 H 5 Rh(C 2 H 4 )P(OMe) 3 .

Synthese und Reaktivität von η5 -Indenyl-trimethylphosphanrhodium(I) - und -rhocüum(III)-Komplexen [1]/Synthesis and Reactivity of η5-Indenyl-trimethylphosphanerhodium (I) and -rhodium(III) Complexes [1]

Abstract The Compounds [(PMe3)2RhCl]2 and [Rh(PMe3)4]Cl react with indenyllithium to give C9H7Rh(PMe3)2. The strong Lewis basicity of this complex is demonstrated by its reactions with NH4PF6, MeI and MeCOCl which lead to the cations [C9H7RhR(PMe3)2]+ (R = H, Me, COMe). The hydrido complex [C9H7RhH(PMe3)2]PF6 reacts with 1,5-C8H12, CO and PMe3 by complete displacement of indene to give [Rh(PMe3)2(C8H12)]PF6, [Rh(PMe3)2(CO)3]PF6 and [Rh(PMe3)4]PF6. Reaction of [C9H7RhH(PMe3)2]PF6 with C2H4 yields an equilibrium mixture containing the cationic tris(ethylene) complex [Rh(PMe3)2(C2H4)3]+ .