Kevin J. Odell

Rapid reversible fission of a C–H bond in a metal complex: X-ray crystal structure of [RhHCl(But2PCH2CH2CHCH2CH2PBut2)]

The occurrence and stereochemistry of a rapid reversible C–H fission in [[graphic omitted]But2)] is established by n.m.r. spectroscopy, including triple resonance INDOR, and by X-ray crystallography.

Preparation of arylplatinum(II) complexes. The interaction of dichloro-(η-cyclo-octa-1,5-diene)platinum(II) and aryltrimethylstannanes

One or both chloride ligands of [Pt(cod)Cl2](cod = cyclo-octa-1,5-diene) can be readily and selectively replaced by aryl groups by treatment of the complex with aryltrimethylstannanes in dichloromethane or sym-tetrachioroethane. Use of 1 mol of SnMe3R usually gives the monoaryl complexes in high yield [e.g. R = 2-furyl, 2-thienyl, benzofuran-2-yl, 2-benzothienyl, 1,2-dihydrobenzocyclobuten-3-yl, or C6H4X (X = H, p-MeO, p-Cl, p-F, p-Me3Si, or p-Me)], but for R =η6-p-MeC6H4Cr(CO)3 the diaryl complex is formed. Use of 2 mol of SnMe3R gives the diaryl complexes in good yield [e.g. R as above; plus C6H4X (X =o-MeO, m-MeO, m-F3C, p-Br, m-F, m-Cl, and p-O2N)], but, for steric reasons, with R = C6H2Me3-2,4,6 only the monoaryl complex is formed. The reactivity of the SnMe3R compounds generally parallels the ease of electrophilic substitution at the corresponding R–H bonds. The arylation method has substantial advantages over those using aryl Grignard or lithium reagents. Aryl compounds, MMe3R, of other Group 4 metals undergo analogous reactions, the reactivity decreasing in the sequence (M =) Pb > Sn Ge > Si. While mixed diaryl complexes can sometimes be made in good yield {e.g.[Pt(cod)-(2-C4H3S)(2-C4H3O)] from [Pt(cod)(2-C4H3S)Cl] and SnMe,(2-C4H3O)}, such preparations can be complicated by exchange of aryl groups between platinum centres; e.g.(i) reaction of [Pt(cod)(2-C4H3S)2] with [Pt(cod)Cl2] followed by addition of 1,2-bis(diphenylphosphino)ethane (dppe) gives [Pt(2-C4H3S)Cl(dppe)] in ca. 100% yield, (ii)[Pt(cod)(2-C8H5O)2] and [Pt(cod)(C6H4Cl-m)2] similarly give some [Pt(2-C8H5O)(C6H4Cl-m)(dppe)], and (iii)[Pt(cod)(3-C8H7)Cl] and SnMe3(C6H4Me-p) similarly give some [Pt(3-C8H7)2(dppe)] and [Pt(C6H4Me-p)2-(dppe)](3-C8H7= 1,2-dihydrobenzocyclobuten-3-yl). The olefin ligand is readily displaced from the aryl com-plexes by neutral ligands, and a wide range of [PtR(Cl)L2] and [PtR2L2] complexes with L =½ dppe or PPh3 have been made. The i.r. and 1H, 13C-{1H}, and 31P-{1H} n.m.r. spectra of the products are discussed. For cis-[ Pt(C6H4X-p)2(PPh3)2] complexes the values of 1J(Pt–P) show a good correlation with σI constants. The norbornadiene (nbd) complex [Pt(nbd)Cl2] reacts with SnMe3(2-C4H3O) to give [Pt(2-C4H3O)(nbd)Cl] in 91% yield, but the corresponding palladium complex [Pd(nbd)Cl2] reacts with SnMe3R (R = C6H4OMe-p or C6H4Me-p) to give a dimeric chloride-bridged complex in which the aryl group is attached to the organic ligand.

Hydrosilylation of carbonyl compounds catalysed by ruthenium complexes

Summary The ruthenium complex [RuCl2(PPh3)3] catalyses the reaction of triethylsilane with ketones, RR′CO, and aldehydes, RCHO, to give the hydrosilylation products RR′CHOSiEt3 and RCH2OSiEt3, respectively, but it is not as effective a catalyst as [RhCI(PPh3)3]. The complex [RuCIH(PPh3)3] was obtained by treatment of [RuCl2(PPh3)3] with triethylsilane, and [RhCl(PPh3)2(CO)] was isolated from reaction between p-methoxybenzaldehyde and triethylsilane catalysed by [RhCl(PPh3)3].

Transition metal—carbon bonds: XLIV. Organo-transition metal complexes containing crown ether groups☆

Some benzo-crown ethers, substituted in the arene ring, are described e.g. 15-X substituted benzo-15-crown-5 ether(1,X = CCPh, CHCHCOOH, CHCHCOOMe, CHCHCOOEt, CHCHCOCl). 15-Iodo-benzo-15-crown-5 and 18-iodo-benzo-18-crown-6, oxidatively add to Pd(PPh3)4 to give trans-[PdIR(PPh3)2], R=(2) or(3)). [Pt(stilbene)(PPh3)2] reacts similarly with the aryl iodides to give trans-[PtIR(PPh3)2](R=(2), (3), (4)-dimethoxy-phenyl. The platinum complexes with R = (2), (3) or (4) appear to form adducts with sodium iodide in solution. trans-[PtIR(PPh3)2] was converted to the corresponding thiocyanate and chloride (via the nitrate). PhCCR (R = (2) or 3,4-dimethoxyphenyl) react with cis-[PtCl2(PPh3)2 in the presence of hydrazine to give [Pt(PhCCR)(PPh3)2] and PhCCR react with [CO2(CO)8] to give [Co2(PhCCR))CO)6], with Ni(C5H5)2 to give [Ni2(C5H5)2(PhCCR)] and with W(CO)6 in acetonitrile to give [W(CO)(PhCCR)3]; PMe2Ph displaces the CO from [W(CO)(PhCCR)3] to give [W(PMe2Ph)(PhCCR)3]. [Cr(CO)6] reacts with the benzo-crown ethers RH, R = (2),(3) or (4) or with 1,2-dimethoxybenzene to give yellow arenechromium tricarbonyl complexes of the type [Cr(CO)3(RH)]. [Cr(CO)3(benzo-15-crown-5) forms a green 11 adduct with NaSCN.

Preparation of diphenylphosphido- and phenylthio-bridged dinuclear platinum(II) complexes by use of trimethyl(diphenylphosphino)- and trimethyl(phenylthio)-silane☆

Abstract The complexes [Pt 2 Cl 2 (μ-Cl) 2 L 2 ] (L = triorganophosphine) react with 2 molar proportions of SiMe 3 (PPh 2 ) in tetrahydrofuran or CH 2 Cl 2 at room temperature to give the corresponding phosphido-bridged complexes trans -[Pt 2 Cl 2 (μ-PPh 2 ) 2 L 2 ]. The same products are formed, in lower yield, by treatment of cis -[PtCl 2 L 2 ] complexes with 1 molar proportion of SiMe 3 (PPh 2 ), and the arsine complex trans -[Pt 2 Cl 2 (μ-PPh 2 ) 2 (AsEt 3 ) 2 ] is produced analogously from cis -[PtCl 2 (AsEt 3 ) 2 ]. The corresponding reaction with trans -[Pt(Cl)H(PEt 3 ) 2 ] gives trans -[Pt 2 H 2 (μ-PPh 2 ) 2 (PEt 3 ) 2 ]. Treatment of trans -[Pt 2 Cl 2 (μ-Cl) 2 L 2 ] complexes with SiMe 3 (SPh) gives cis -[Pt 2 Cl 2 (μ-Cl)(μ-SPh)L 2 ], trans -[Pt 2 Cl 2 (μ-SPh) 2 L 2 ], or trans -[Pt 2 (SPh) 2 (μ-SPh) 2 L 2 ] depending upon the molar proportion of SiMe 3 (SPh) and the temperature used, while cis -[PtCl 2 L 2 ] gives trans -[Pt(SPh) 2 L 2 ]. Ethylation of trans -[PtCl 2 (μ-SPh 2 )L 2 ] (L = P-n-Pr 3 ) with [OEt 3 ]BF 4 appears to give the chloride-bridged trans -[Pt 2 (μ-Cl) 2 (SEtPh) 2 L 2 ][BF 4 ] 2 .

Use of aryltin compounds in the preparation of diaryl- and diaroyl-di-µ-chloro-bis(triorganophosphine)diplatinum(II) complexes

The complexes cis-[Pt(C2H4)Cl2L](L = triorganophosphine) react with compounds SnRMe, (R = aryl)(1 mol equivalent) to give the chloride-bridged arylplatinum complexes [Pt2R2Cl2L2], which exist in solution as mixtures of cis and trans isomers. The [Pt2R2Cl2L2] complexes react with ligand species L′[L′= NCMe, SBut2, pyridine, NBunH2, AsPh3, PEt3, PBun3, PPh3, or P(OPh)3] to give the mononuclear complexes [PtR(Cl)L(L′)], and this represents an excellent route to mononuclear complexes having four different ligands on platinum. Cyclo-octa 1,5-diene (cod), however, gives [PtR(Cl)L2] and [Pt(cod)R(Cl)], while 2,2′-bipyridyl (bipy) gives the salt [PtR(bipy)L]Cl. Sodium thiocyanate reacts with [Pt2(C6H4Me-p)2Cl2(PEt2Ph)2] to give the thiocyanate-bridged [Pt2(C6H4Me-p)2(PEt2Ph)2(µ-SCN)2], and [NEt4]Cl reacts with [Pt2(C6H4Bun-p)2(PMe2Ph)2] to give the salt [NEt4][Pt(C6H4Bun-p)Cl2(PMe2Ph)]. Excess of SnRMe3 causes decomposition of [Pt2R2Cl2L2] to give the mononuclear complexes [PtR(Cl)L2]. The carbonyl complexes cis-[Pt(CO)Cl2L] react with SnRMe3 to give the binuclear aroyl complexes [Pt2(COR)2Cl2L2], which also exist in solution as mixtures of cis and trans isomers. These complexes react with neutral ligand species L′= NBunH2 or P(OPh)3 to give the mononuclear complexes [Pt(COR)Cl(L)L′]. but cod reacts with [Pt2(COC6H4But-p)2Cl2(PMe2Ph)2] to give [Pt(COC6H6But-p)Cl-(PMe2Ph)2]. Again excess of SnRMe3 causes decomposition, to give [Pt(COR)Cl(L)] complexes. Heating of the aroyl complex [Pt2(COC6H4Me-p)2Cl2(PEt3)2] gives some of the corresponding aryl complex [Pt2(C6H4Me-p)2-Cl2(PEt3)2]. The 31P-{1H} n.m.r. spectra of the complexes have been recorded, and are used extensively in the identification of products.

The reaction between [Pt(cod)Cl(PMe2Ph)]BF4 and aryltrimethyltin compounds

Abstract The complex [Pt(cod)Cl(PMe2Ph)]BF4 reacts in dichloromethane with SnArMe3 compounds having Ar = 2-thienyl, 2-benzol [b]thienyl, or 2-benzo[b]furyl to give air-stable cationic aryl complexes [Pt(cod)Ar(PMe2Ph)]BF4. No reaction takes place when Ar  Ph. The cod ligand in the new complexes can be readily replaced by ligands such as PMe2Ph, dppe, or 4-dimethylaminopyridine. The1H and31P-{1H} NMR parameters of the various complexes are reported.

A silatrane–platinum complex, trans-[PtCl{Si(OCH2CH2)3N}(PMe2Ph)2] with a planar nitrogen and No Si–N bond; X-ray crystal structure

An X-ray crystal structure analysis of trans-[PtCl{Si(OCH2CH2)3N}(PMe2Ph)2] reveals a square-planar co-ordination geometry for platinum, a non-bonded Si–N distance of 2·89(1)A, and trigonal-planar stereochemistry for nitrogen.

Aryltin compounds as reagents for the formation of aryltransition metal bonds

Abstract In complexes of platinum and rhodium, active anionic ligands can be replaced by aryl groups by use of aryltrimethyltin reagents under mild conditions.

The reaction between cis-bis(trifluoroacetato)bis(trioganophosphine)platinum(II) and tetraorganotin compounds

The complex cis-[Pt(O2CCF3)2L2](L = PMe2Ph) reacts with SnRMe3 compounds (R = aryl) to give trans-[PtR(O2CCF3)L2] and cis-[PtR2L2], except for the sterically hindered mesityltrimethyltin which gives mainly trans-[PtMe(O2CCF3)L2]. The latter is also the main product from SnMe3(CH2Ph). For L = PPh3, SnMe3Ph, and SnMe3(C6H4Me-p) give mainly cis-[PtMe(O2CCF3)L2]. For L = PMe2Ph, SnMe4 gives only trans-[PtMe(O2CCF3)L2], but, for L = PPh3, cis-[PtMe2L2] is also formed. The most reactive tin compound used, trimethyl(2-thienyl)tin, readily reacts with cis-[Pt(O2CCF3)L2](L = PMe2Ph or PEt2Ph) or [Pt(cod)(O2CCF3)2] to give exclusively cis-[Pt(C4H3S-2)2L2] or [Pt(cod)(C4H3S-2)2]. 31P-{1H} N.m.r. parameters are given.