Raymond D. W. Kemmitt

Zerovalent palladium and platinum complexes of aminomethylphosphines. Crystal structure of the palladium(0) dibenzylideneacetone complex [Pd(PhCHCHCOCHCHPh){((C6H11)2PCH2)2NMe}]

Abstract Tris(dibenzylideneacetone)dipalladium and bis(dibenzylideneacetone)platinum react with N, N-bis(dicyclohexylphosphinomethyl)methylamine, (Cy2PCH2)2NMe (Cy = cyclohexyl), and with N, N-bis(diphenylphosphinomethyl)methylamine, (Ph2PCH2)2NMe (Ph = phenyl), to give the complexes [M(dba){(R2PCH2)2NMe}] (M  Pd or Pt, dba = dibenzylideneac ), R  Cy or Ph. Thezerovalent platinum complex [Pt(PPh3){(Cy2PCH2)2NMe}] can be obtained by hydrazine hydrate reduction a mixture of [PtCl2Cy2PCH2)2NMe] and triphenylphosphine or one of cis-[PtCl2(PPh3)2] and (Cy2PCH2)2NMe. The crystal structure of [Pd(dba){(Cy2PCH2)2NMe}] has been determined and some reactions of the complexes are reported.

Preparation and reactivity of some halogen bridged complexes of rhodium(I)

Abstract Hydrogen chloride or bromide reacts with the square-planar rhodium(I) complexes, Rh(Acac)(CO)L, (L = PPh3 or AsPh3) to give the halogen bridged dimers, [RhX(CO)L]2, (X =Cl or Br) which are cleaved by donor ligands, L′, to give the mixed ligand complexes, RhX(CO)LL′, [L =PPh3; L′ = AsPh3 SbPh3 or P(OPh)3; L = AsPh3, L′= SbPh3 or P(OPh)3]. Reactions of the complexes, Rh(Acac)(PPh3)2 and Rh(Acac)(1,5-cyclooctadiene) with carbon monoxide, tetrafluoroethylene and methyl iodide are also reported.

Reactions between trimethylenemethane metal complexes and the carbon–nitrogen double bond: nickel and palladium catalysed synthesis of pyrrolidines

The d10 nickel complex [Ni{P(OEt)3}4] catalyses the cycloaddition of trimethylenemethane to the CN double bond of an imine to afford a high-yield synthesis of 4-methylenepyrrolidines.

Synthesis and electrospray mass spectrometry of platinum(II) complexes of 5,5-diethylbarbituric acid (Hdebarb); crystal structure of cis-[PtCl(debarb)(PPh3)2]·CH2Cl2

The reactions of 5,5-diethylbarbituric acid (Hdebarb; 1H,3H,5H-5,5-diethylpyrimidine-2,4,6-trione), either as the monosodium salt or free acid in the presence of ancillary base (silver oxide or triethylamine), with platinum(II) halide complexes yielded mono(barbiturato) complexes cis-[PtX(debarb)L2][X = Cl, Br or I; L = PPh3; L2= 1,2-bis(diphenylphosphino)ethane (dppe) or 1,1′-bis(diphenylphosphino)ferrocene (dppf)]. A single-crystal structure determination of cis-[PtCl(debarb)(PPh3)2]·CH2Cl 2 showed that the plane of the N-bonded barbiturate ligand is approximately perpendicular to the platinum co-ordination square plane, rendering the two ethyl substituents inequivalent. Electrospray mass spectrometry has also been used to study these complexes, with the major ions for cis-[PtX(debarb)L2] being [Pt(debarb)L2]+ and [Pt(debarb)(NCMe)L2]+, though molecular ions [M + H]+ are also observed for all complexes. A number of cationic derivatives of the type [Pt(debarb)L2L′]+(L = PPh3 or L2= dppe; L′= pyridine or PPh3) are also reported.

Thiadiazatrimethylenemethane and N,N′,P-triphenylphosphonothioic diamide complexes of platinum(II)

Reaction of N,N′-diphenylthiourea with cis-[PtCl2L2][L = PPh3, PMePh2, PMe2Ph, PEt2Ph, PPh2(NEt2) or L2= Ph2PCH2CH2PPh2(dppe)] in the presence of silver(I) oxide gives the thiadiazatrimethylenemethane complexes [[graphic omitted]Ph}L2], an X-ray study on [[graphic omitted]Ph}(PPh3)2] establishing the presence of a flat [graphic omitted] ring. Related [graphic omitted] ring complexes which contain a reactive nucleophilic PNPh group are formed upon treatment of PhNHP (S)(Ph) NHPh with cis-[PtCl2L2][L = PPh3, L2= dppe, Ph2P(CH2)3PPh2 or Ph2P(CH2)4PPh2] and potassium hydroxide. Treatment of [[graphic omitted]Ph}L2] with MeI afforded an aminophosphonium salt, whilst with substrates containing either CO or CS functionalities new complexes of the type [[graphic omitted]Ph}L2] or [[graphic omitted]}L2] were formed respectively.

Decomposition pathways of platinum(II) complexes containing alkyl and halide ligands investigated by electrospray mass spectrometry. The X-ray crystal structure of cis-[PtCl{CH2C(O)CH2Cl}(PPh3)2]

Abstract The platimun(II) alkyl-halide complexes cis[PtCl{CH2C(O)CH2Cl}(PPh3)2], cis- [PtCl{CH2C(O)CH3}(PPh3)2], trans-[PtI(Me)(PPh3)2], [Pt{EtSCH2C(O)CH2}Br(PPh3)] and [Pt{MeSCH2C(O)CH2}I(PPh3)] have been investigated by electrospray mass spectrometry (ESMS). For all complexes, loss of halide ion provides the initial ionization pathway and the resulting ions may contain coordinated ligands from the solvent (acetonitrile, ammonia and added pyridine). At high cone voltages, all complexes undergo cyclometallation of one of the triphenylphosphine ligands. However, for the chloroacetonyl complex cis-[PtCl{CH2C(O)CH2Cl}(PPh3)2], fragmentation to the ion [PtCl(PPh3)2]+ preceeds cyclometallation. It is proposed that this complex fragments via initial oxidative addition of the CCl bond, forming an unstable platina (IV)cyclobutan-3-one (oxodimethylenemethane) complex, which undergoes reductive elimination of cyclopropanone. The X-ray crystal structure of cis-[PtCl{CH2C(O)CH2Cl}(PPh3)2] is also reported.

Carbon-antimony bond fission in reactions of triphenylantimony with palladium(II): Crystal structures of trans-chloro(phenyl) bis(triphenylantimony) palladium(II) and trans-bromo(phenyl) bis(triphenylantimony) palladium(II)

Abstract Triphenylantimony reacts with [PdX2cod] (X = Cl or Br; cod = cyclo-octa-1,5-diene) in refluxing dichloromethane to give the palladium phenyl complexes trans-[PdXPh(SbPh3)2]. Treatment of palladium(II) chloride with triphenylantimony in refluxing acetone—diethyl ether solution also gives trans-[PdClPh(SbPh3)2], but reaction of palladium(II) bromide with triphenylantimony affords cis-[PdBr2(SbPh3)2]. A small amount of trans-[PdClPh(SbPh3)2] is present in samples of cis-[PdCl2(SbPh3)2] prepared from the reaction of Na2PdCl4 with triphenylantimony in aqueous acetone—diethyl ether. The single crystal X-ray structures of trans-[PdXPh(SbPh3)2] (X = Cl or Br) are described.

Reactions of fluoro-olefins, chloro-olefins and related molecules with carbonatobis(triphenylarsine)platinum(II) in ethanol

Abstract Tetrafluoroethylene, hexafluoropropene, trifluoroethylene or tetracyanoethylene, react with carbonatobis(triphenylarsine)platinum(II) in ethanol at 40° to give the zerovalent platinum-olefin complexes Pt(Olefin)(AsPh 3 ) 2 . Hexafluoro-2-butyne similarly gives Pt(CF 3 CCCF 3 )(AsPh 3 ) 2 . Corresponding reactions with chlorotrifluoroethylene, bromotrifluoroethylene or tetrachloroethylene give the vinyl complexes, PtX(CFCF 2 )(AsPh 3 ) 2 (X = Cl or Br) and PtCl(CClCCl 2 )(AsPh 3 ) 2 respectively, but tetrabromoethylene and tetraiodoethylene give PtY 2 (AsPh 3 ) 2 (Y = Br or I). The olefin complexes Pt(CF 2 CFX)(AsPh 3 ) 2 rearrange to vinyl complexes in ethanol at 40° and it is apparent that the triphenylarsine complexes undergo the vinyl rearrangement more readily than the corresponding triphenylphosphine complexes. Lithium iodide is also shown to react with Pt(C 2 F 4 )(PPh 3 ) 2 in benzene/ethanol at 95° to give PtI(CFCF 2 (PPh 3 ) 2 .

The interaction of tin(II) chloride with some allyl complexes of platinum and palladium and diene complexes of rhodium

Abstract The interaction of tin(II) chloride with Pt(π-C 3 H 5 )(PPh 3 ) 2 Cl gives the ionic and covalent complexes, [Pt(π-C 3 H 5 )(PPh 3 ) 2 ][SnCl 3 ] and PtSnCl 3 (π-C 3 H 5 )(PPh 3 ) respectively. Palladium complexes analogous to the latter have also been prepared. The reaction of tin(II) chloride with chloro(norbornadiene)rhodium(I) dimer in the presence of a tertiary phosphine or arsine ligand L leads to a variety of five coordinate monomers of the type RhSnCl 3 (NBD)L 2 and the five coordinate rhodium(I) complexes, RhSnCl 3 (butadiene) 2 and RhSnCl 3 (CO)(SbPh 3 ) 3 have also been prepared. The structures of the complexes have been investigated by 1 H NMR and IR spectroscopy.

Preparation and reaction of platinum(II) complexes of N,N-bis(dicyclohexylphosphinomethyl)aminomethane. Crystal structures of (Cy2PCH2)2NMe (Cy = cyclohexyl) and [PtX2{(Cy2PCH2)2NMe}], (X = Cl and I)

Treatment of [Cy2P(CH2OH)2]Cl with MeNH2 in the presence of Et3N affords a high yield of the phosphine (Cy2PCH2)2NMe (1) (dcpam) which has been characterised by a single crystal X-ray structure. Treatment of [PtX2(COD)], (COD=cyclo-octa-1,5-diene, X= Cl or I) with (1) affords the platinum complexes [PtX2{(Cy2PCH2)2NMe}] (2). The chloride complex, (2a), reacts with t-BuNC to afford [PtCl(t-BuNC)-{(Cy2PCH2)2NMe}]Cl (3) and treatment of (2a) with 2-mercapto-1-methylimidazole affords [Pt{SCN(Me)CHCH=N(Me)}{Cy2PCH2)2NMe}]Cl (5). The reaction of (2a) with 2-acetamidoacrylic acid in the presence of silver(I) oxide affords the carbon bonded isomer (8a) only whereas a similar reaction using [PtCl2{Ph2P-(CH2)3PPh2}] affords a mixture of the azaallyl complex (7) and the carbon bonded isomer (8b) which can be separated by fractional crystallisation. The crystal structures of PtX2{(Cy2PCH2)2NMe}] are also reported.