H.C. Clark

Reactions of (π-1,5-cyclooctadiene) organoplatinum(II) compounds and the synthesis of perfluoroalkylplatinum complexes

Abstract An improved synthesis for the complexes PtR 2 (COD), [where COD = 1,5cyclooctadiene, R = I, CH 3 , C 2 H 5 , CH 2 C 6 H 5 , CH 2 Si(CH 3 ) 3 , C 6 H 5 ] and the reactions with HCl (generated in situ ) to give PtRCl(COD) are described. The coupling constant J(Pt-H) to the olefinic carbons varies with the trans -influence of the trans -ligand. Displacement of COD from Pt(CH 3 ) 2 (COD) by L (where L = isocyanide, phosphine, amine, bipyridyl and trimethylarsine) gave a series of compounds cis -Pt(CH 3 ) 2 L 2 . The oxidative addition of methyl iodide to PtR 2 (COD)(R = CH 3 , CH 2 CH 3 ) gave the platinum(IV) compounds [Pt(CH 3 ) 3 I] 4 and [Pt(CH 3 )(CH 2 CH 3 ) 2 I] 4 . Diethylmethylplatinum(IV) iodide reacted with 4-methylpyridine (γ-Pic) to give Pt(C 2 H 5 ) 2 (CH 3 )(γ-Pic) 2 I and with AgClO 4 and pyridine to give [Pt(C 2 H 5 ) 2 (CH 3 )(NC 5 H 5 ) 3 ](ClO 4 ). The reaction of R 2 Pt(COD) (R = CH 3 and C 2 H 5 ) with iodine or bromine gave the Pt IV compounds [PtR 2 X 2 ] x . Several reactions of these compounds are discussed. The NMR spectrum of Pt(CH 3 ) 2 (CNC 2 H 5 ) 2 Br 2 is unusual in that coupling of the 14 N nucleus with the ethyl hydrogens is observed. The reaction of acetylchloride with Pt(CH 3 ) 2 (COD) gave the Pt IV compound [Pt(CH 3 ) 2 (COCH 3 )Cl] 4 . Further reaction of γ-picoline with the acyl compound gave 2 isomers of Pt(CH 3 ) 2 (COCH 3 )(γ-Pic) 2 Cl as predicted by cleavage of a cubane-type structure. The reaction of iodine with PtR 2 (COD)(R = CH 2 C 6 H 5 ) gave a mixture of [PtR 2 I 2 ] x and PtRI(COD). whereas for R = CH 2 Si(CH 3 ) 3 only PtRI(COD) was obtained. The possible mechanisms for these reactions are discussed. Trifluoromethyl iodide reacted with Pt(CH 3 ) 2 (COD) to give Pt(CF 3 ) 2 (COD) and displacement reactions of COD with ligands L, [where L = CNC 2 H 5 , P(CH 3 ) 2 (C 6 H 5 ), As(CH 3 ) 3 , Bipy, γ-Pic, Sb(C 6 H 5 ) 3 , As(C 6 H 5 ) 3 , (C 6 H 5 ) 2 PCCP(C 6 H 5 ) 2 and (CH 3 ) 2 NCH 2 CH 2 N(CH 3 ) 2 ] gave a series of compounds cis -Pt(CF 3 ) 2 L 2 . Oxidative addition reactions with iodine and the stereochemistry of the resultant Pt IV compounds are described.

Organoindium chemistry: I. A convenient preparation of dimethylindium(III) derivatives

Abstract A convenient method is described for the one-step synthesis of trimethylindium, or dimethylindium(III) chloride, the final product depending on the length of the reaction. The preparations of dimethylindium(III) fluoride, bromide, and iodide are described, and on the basis of molecular weights and infrared spectra, dimeric, halogen-bridged structures are proposed. Other new dimethylindium(III) derivatives include the 8-hydroxyquinolinate, the o-nitrophenoxide, the acetate, and the 1,1-bis(trifluoromethyl)ethoxide, these are being prepared from trimethylindium. Lewis base adducts of dimethylindium iodide and chloride with pyridine and triphenylphosphine have also been prepared.

Oxidative addition, reductive elemination, and isomerization reactions of organoplatinum complexes

Abstract The investigation of a variety of oxidation addition reactions of I 2 , CH 3 I, and CF 3 I with trans -PtRI[P(CH 3 ) 2 (C 6 H 5 )] 2 (R = C 6 H 5 , CH 3 ) and the stereochemistry of the resulting platinum(IV) compounds are discussed. The additions of CH 3 I, and CF 3 I to cis PtR 2 L 2 [where R = C 6 H 5 , CH 3 ; L = CNC 6 H 4 CH 3 , As(CH 3 ) 3 or P(CH 3 ) 2 (C 6 H 5 )] have been investigated and the stereochemistry of the platinum(IV) compounds was found to be dependent on both R and L. Stereochemical rearrangements can be facilitated by the formation of Pt IV cations. In several instances reductive elimination occurred to give Pt II compounds. Factors governing the isomerization and reductive elimination reactions are discussed. Kinetic data for the oxidative addition of methyl iodide and acetyl chloride to cis -Pt(CH 3 ) 2 (CNC 6 H 4 CH 3 ) 2 are given.

Chemistry of metal hydrides : XVII. Isocyanide insertion into the PtH bond, and the formimidoyl ligand

Abstract The complexes trans -[PtH(CNR)L 2 ]Cl (R = p -tolyl; L = PEt 3 , PMe 2 Ph) undergo insertion of isocyanide into the platinumhydride bond in non-polar solvents to give the platinum formimidoyl complexes trans -PtCl(CHNR)L 2 , apparently via five coordinate intermediates of the type HPtCl(CNR)L 2 . Other complexes prepared include trans -PtX(CHNR)(PEt 3 ) 2 (X = I or CN), trans -[Pt{C(OMe)NR}(CHNR)(PEt 3 ) 2 ] and trans -[Pt{C(NHR) 2 }(CHNR)(PMe 2 Ph) 2 ]Cl. The infrared ( v (CH) 2800 cm −1 and v (CN) ca. 1550 cm −1 ) and 1 H NMR (τ(PtCH) −0.4 to −1.1 ppm) parameters characterize the formimidoyl ligand. The 1 H NMR spectra also show the presence of equilibria between syn and anti isomers, the mechanism of interconversion being thought to involve rotation through a polarized transition state. Contact shift studies on the complexes trans -PtCl(CHNR)L 2 indicate that the basicity of the imidoyl nitrogen varies between complexes and between syn and anti isomers of the same complex, but in general protonation—deprotonation results show it to be comparable to that of a weak amine.

Organoindium chemistry II. Derivatives of dimethylindium(III) and methylindium(III)

Abstract The synthesis and stereochemistry of several classes of organoindium derivatives are described. Four-coordination about indium, in a distorted tetrahedral stereochemistry, is most common, and occurs in a series of 1:1 complexes of Lewis bases with dimethylindium halides and in two organoindium anions, dimethylindium dichloride and tetramethylindate. These new organoindium derivatives are similar to analogous aluminium and gallium compounds. 1:1 Complexes of dimethylindium halides with bidentate ligands (1,10-phenanthroline, 2,2′-bipyridine) were synthesized and probably contain five-coordinate indium. Several methylindium dichloride derivatives were synthesized and the parent compound is compared to the gallium and thallium analogues.

Chemistry of metal hydrides

Abstract Useful new hydrido diphenylmethyl- and dimethylphenyl-phosphine platinum(II) complexes have been synthesized by the reduction of cis -PtX 2 (PR 3 ) 2 (X = Cl, Br, I and NCS; PR 3 = PPh 2 Me: X = Cl and Br; PR 3 = PMe 2 Ph) or trans -Pt(CN) 2 (PPh 2 Me) 2 with sodium borohydride. Cationic hydrido platinum(II) complexes were also prepared via the interesting intermediate, trans -[PtH(PPh 2 Me) 2 (Acetone)] + , or from the reaction of trans -PtH(CN)(PR 3 ) 2 (PR 3 = PPh 2 Me and PMe 2 Ph) with a neutral strong ligand such as a phosphine or an alkyl isocyanide in the presence of NaPF 6 . Proton NMR and infrared spectroscopic studies of these complexes provide information concerning: 1. the existence of different crystalline modifications of trans -PtH(CN)(PPh 2 Me) 2 ; 2. the relative trans influence of both thiocyanato and isothiocyanato ligands; 3. the magnetic anisotropic effect of the isoelectronic ligands, CN − , CNR and CO; 4. the facile phosphine exchange reactions of trans -PtH(CN)(PPh 2 Me) 2 and trans -Pt(CN) 2 (PPh 2 Me) 2 .

Some reactions of allene and acetylenes with vinylplatinum and methylpalladium complexes

Abstract The reactions of cationic vinylplatinum complexes, Pt(R 1 CCHR 2 (PEt 3 ) 2 -(acetone) + PF 6 − , with allene and activated acetylenes yield π-allyl and δ-butadienyl products, respectively. Similar reactions of Pd(CH 3 )X(Diphos) (X = Cl, NO 3 , solvent, Diphos = 1,2-bis(diphenylphosphino)ethane) with acetylenes are also described. Factors affecting these insertion reactions are discussed.

Reactivity of metalmetal bonds : XII. The preparation of some phenylchloro group IVB derivatives of pentacarbonylmanganese and (π-cyclopentadienyl)dicarbonyliron and their reactivities towards pentafluorophenyllithium☆

Abstract The reaction of the appropriate phenylgermanium halide with the transition metal anions Mn(CO) — 5 or Fe(CCO) 2 Cp — (M′) in THF gave the compounds Ph 3— n Cl n GeM′ ( n = 1 or 2), while the analogous silicon compounds were prepared by the reaction of the appropriate phenylchloro- or phenylfluorophenyl-silane with the transition metal carbonyl dimers. The reactivities of the compounds Ph 3— n Cl n MM′ [ n = 1 to 3; M = Si, Ge or Sn and M′ = Mn(CO) 5 or Fe(CO) 2 Cp] towards pentafluorophenyllithium have been found to depend upon M, M′ and teh number of phenyl groups bonded to the Group IV metal. With M′  Mn(CO) 5 the reativity decreased in the order Sn ≈ Ge > Si. For infrared, NMR and 57 Fe Mossbauer spectra of these and related compounds are discussed.

The reactivity of metal—metal bonds VIII. A comparative study of the SiFe, GeFe and SnFe bonds, and some further reactions of the SnMn bond

Abstract The reactions of (CH3)3SnMn(CO)5 with perfluoropropene, perfluoro-2-butyne and perfluorocyclobutene are described. Similar reactions of (CH3)3MFe(CO)2(π-C5H5) (M = Si, Ge, or Sn) with perfluorocyclobutene, perfluoro-2-butyne, and 3,3,3-trifluoropropyne are described, leading to the characterization of insertion products of the types (CH3)3M(CF3)CC(CF3)Fe(CO)2(π-C5H5) and (CH3)3MC2H(CF3)Fe(CO)2(π-C5H5). When M = Sn, other products formed by the elimination of trimethyltin fluoride from 1/1 insertion products, are also formed. The mechanisms of these reactions appear to involve four-centred type transition species.

Reactivity of metalmetal bonds VI. Cleavage reactions of (trimethyltin) pentacarbonyl manganese

Abstract The cleavage reactions of (CH 3 ) 3 SnMn(CO) 5 with chlorine, iodine, hydrogen chloride, hydrogen bromide, hydrogen iodide, iodine menochloride, and trifluoroiodomethane are described, as well as some similar reactions of (C 5 H 5 ) 3 PbMn(CO) 5 . The results are compared with analogous reactions of other metal−metal bonded organometallic compounds. Boron trifluoride with (CH 3 ) 3 SnMn(CO) 5 gave [(CH 3 ) 2 - SnMn(CO) 5 ]BF 4 , the same compound also being formed from silver tetrafluoroborate and Cl(CH 3 ) 2 SnMn(CO) 5 . the analogous hexafluorophosphate and hexafluoroarsenate salts containing the [(CH 3 ) 2 SnMn(CO) 5 ] + ion could not be obtained from similar reactions. The preparation of CF 3 (CH) 2 SnMn(CO) 5 and [CH 3 ) 2 - SnMn(CO) 5 ]BF 3 CF 3 are described, but the reaction of sodium tetraphenylborate with Cl(CH 3 ) 2 SnMn(CO) 5 gave C 6 H 5 (CH 3 ) 2 SnMn(CO) 5 and no the expected tetraphenylborate salt. The infrared spectra of [(CH 3 ) 2 SnMn(CO) 5 ]BF 4 and the related BF 3 CF 3- salt are very similar to those of their trimethyltin analogues, and their probable pentacoordinate structures are discussed.