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The reaction of the cyclic peroxides cyclobutane malonoyl peroxide and cyclopentane malonoyl peroxide to dimethylplatinum(II) complexes with the bidentate nitrogen donor ligand 4,4'-di-t-butyl-2,2'-bipyridine (bubpy) gave a mixture of the products of cis and trans oxidative addition, [Pt[Me.sub.2]{[([O.sub.2]C).sub.2]C([C.sub.3][H.sub.6])}(bubpy)] and [Pt[Me.sub.2]{[([O.sub.2]C).sub.2]C([C.sub.4][H.sub.8])}(bubpy)], respectively. The cis isomers exist with a chelating dicarboxylate ligand, forming a six-membered ring, while the trans isomers are thought to exist as oligomers, which may react with water or solvent to give complexes containing a monodentate dicarboxylate ligand. Equilibration of the product of cis oxidative addition, cis-[Pt[Me.sub.2]{[([O.sub.2]C).sub.2]C([C.sub.3][H.sub.6])}(bubpy)], with oxalic or phthalic acid to give equilibria with the oxalate cis-[Pt[Me.sub.2]([O.sub.4][C.sub.2])(bubpy)] or phthalate cis-[Pt[Me.sub.2]{[([O.sub.2]C).sub.2][C.sub.6][H.sub.4] }(bubpy)] derivative, respectively, indicated the expected sequence of chelate stability oxalate > cyclobutane malonate > phthalate. Key words: platinum, peroxide, oxidative addition, organometallic. La reaction de peroxydes cycliques, le peroxyde de cyclobutane malonoyle et le peroxyde de cyclopentane malonoyle, avec des complexes de dimethylplatine (II) en presence du 4,4'-di-t-butyl-2,2'-bipyridine (bubpy), ligand bidentate donneur d'azote, a forme un melange de produits d'addition oxydante cis et trans, le [Pt[Me.sub.2]{[([O.sub.2]C).sub.2]C([C.sub.3][H.sub.6])}(bubpy)] et le [Pt[Me.sub.2]{[([O.sub.2]C).sub.2]C([C.sub.4][H.sub.8])}(bubpy)], respectivement. Les complexes avec un ligand dicarboxylate chelatant existent sous forme d'isomeres cis et forment un cycle a six atomes, tandis qu'on croit que les isomeres trans existent sous forme d'oligomeres qui peuvent reagir avec l'eau ou un solvant pour produire des complexes comprenant un ligand dicarboxylate monodentate. L'equilibration du produit d'addition oxydante cis, le cis-[Pt[Me.sub.2]{[([O.sub.2]C).sub.2]C([C.sub.3][H.sub.6])}(bubpy)], avec l'acide oxalique ou phtalique qui se produit pour former respectivement a l'etat d'equilibre les derives cis-[Pt[Me.sub.2]([O.sub.4][C.sub.2])(bubpy)] oxalate ou cis- [Pt[Me.sub.2]{[([O.sub.2]C).sub.2][C.sub.6][H.sub.4]}(bubpy)] phtalate, revele la sequence de stabilite attendue des chelates : oxalate > malonate de cyclobutane > phthalate. [Traduit par la Redaction] Mots-cles : platine, peroxyde, addition oxydante, organometallique., Introduction Platinum metal and platinum complexes both play important roles in oxidation catalysis, especially using molecular oxygen or hydrogen peroxide as oxidants. (1-4) Combining C-H bond activation with oxidation is [...]

A computational investigation about the Lewis acid-base adducts between bases [Cp.sub.2]M[H.sub.2] (M = Mo, W) and acids B[X.sub.3] (X = F, Cl) and [Al([CH.sub.3].sub.3] is presented. Density functional methods based on pure and hybrid correlation-exchange functionals and relativistic corrections based on the zero order relativistic approximation (ZORA) have been applied. A comparison with experimental data has been addressed to give insights about the nature of the acid-base interaction with the aim to evaluate the role of the transition metal in charge donation toward the acid centre. In this respect, the likelihood of proposed criteria for recognizing the presence of transition-metal direct charge donation has been discussed. Key words: metallocenes, Lewis basicity, density functional theory (DFT), atoms in molecules (AIM), zero order relativistic approximation (ZORA). On a effectue une etude theorique des adduits acide-base de Lewis entre les bases [Cp.sub.2]M[H.sub.2] (M = Mo, W) et les acides B[X.sub.3] (X = F, Cl) et [Al([CH.sub.3].sub.3]. On a utilise les methodes de la fonctionnelle de la densite en faisant appel a des fonctionnelles de correlation-echange pures ainsi qu'hybrides et on a applique des corrections relativistes basees sur l'approximation relativiste d'ordre zero (AROZ). Une comparaison avec les donnees experimentales a ete realisee afin d'obtenir des informations sur la nature de l'interaction acide-base qui permettraient d'evaluer le role du metal de transition dans le transfert de charge vers le centre acide. Dans cette optique, on discute du potentiel d'utilite des criteres proposes pour reconnay tre la presence d'un transfert de charge direct de la part du metal de transition. Mots-cles : metallocenes, basicite de Lewis, theorie de la fonctionnelle de la densite (TFD), atomes dans une molecule << AIM >>, approximation relativiste d'ordre zero (AROZ). [Traduit par la Redaction], Introduction The acid-base adduct between bis(cyclopentadienyl)dihydridotungsten ([Cp.sub.2]W[H.sub.2]) and B[F.sub.3] was firstly communicated by Shriver (1) in 1963. It represented one of the first (and representative) examples of Lewis base behaviour [...]

The oxidative addition of alkyl bromides RC[H.sub.2]Br (R = [C.sub.5][H.sub.4]N, [C.sub.6][H.sub.4]CN, C[H.sub.2][C.sub.6][H.sub.4]C[O.sub.2]H, or C[H.sub.2][C.sub.6][H.sub.4]C[H.sub.2]C[O.sub.2]H) to dimethylplatinum(II) complexes [Pt[Me.sub.2](LL)] (LL = diimine ligand) gives the corresponding organoplatinum(IV) complexes [PtBr[Me.sub.2](C[H.sub.2]R)(LL)] containing functionality in the alkyl group RC[H.sub.2]. The pyridyl derivatives can be protonated, while abstraction of the bromide ligand from [PtBr[Me.sub.2](C[H.sub.2]R)(LL)] can form cationic complexes, which can react with water or form oligomers by self-assembly. Key words: platinum, organometallic, hydrogen bond, supramolecular. L'addition oxydante de bromures d'alkyle, RC[H.sub.2]Br [R = [C.sub.5][H.sub.4]N, [C.sub.6][H.sub.4]CN, C[H.sub.2][C.sub.6][H.sub.4]COOH ou C[H.sub.2][C.sub.6][H.sub.4]C[H.sub.2]COOH] sur des complexes de dimethylplatine(II) [Pt[Me.sub.2](LL)] [LL = ligand diimine], conduit a la formation de complexes organoplatine(IV) [PtBr[Me.sub.2](C[H.sub.2]R)(LL)] comportant une fonctionnalite dans le groupe alkyle RC[H.sub.2]. Les derives pyridyles peuvent etre protones alors que l'enlevement du ligand bromure a partir de [PtBr[Me.sub.2](C[H.sub.2]R)(LL)] peut conduire a la formation de complexes cationiques qui peuvent reagir avec de l'eau ou former des oligomeres par autoassemblage. Mots-cles : platine, organometallique, liaison hydrogene, supramoleculaire. [Traduit par la Redaction], Introduction The oxidative addition of small molecules to platinum(II) complexes to form organoplatinum(IV) complexes can be a key step in catalysis, and so this type of reaction has been studied [...]

The preparation and characterization of cationic, dinuclear complexes of the type trans-[Pt[([PPh.sub.3]).sub.2] (σ-[C.sub.6][H.sub.4]NHMe) -μ-L-Pt[([PPh.sub.3].sub.2] (σ-[C.sub.6][H.sub.4]NHMe)][(OTf).sub.2] (L = 4,4'-bipyridine, 4,7-phenanthroline, 4,4'-dipyrazolylmethane, and 1,1?-diphenyl-4,4'-dipyrazolylmethane; OTf = trifluoromethanesulfonate (triflate)) containing two [C.sup.3]-N-methylbenzamide ligands are described. The key structural feature of the cationic complexes is the presence of two convergent amide groups that may allow for charge-assisted, H-bonding interactions in solution with suitable heteroaromatic guest molecules such as nucleobases. Key words: organoplatinum(II) complex, organometallic host, dinuclear complex, N-methylbenzamide. On decrit la preparation et la caracterisation de complexes cationiques dinucleaires du type trans-[Pt[([PPh.sub.3]).sub.2] (σ-[C.sub.6][H.sub.4]NHMe)-μ-L-Pt[([PPh.sub.3].sub.2] (σ-[C.sub.6][H.sub.4]NHMe)][(OTf).sub.2] [L= 4,4?-bipyridine; 4,7-phenanthroline; 4,4?-dipyrazolylmethane; et 1,1'-diphenyl-4,4'-dipyrazolylmethane; OTf = trifluoromethanesulfonate (triflate)] contenant deux ligands [C.sup.3]-N-methylbenzamide. La caracteristique structurale cle des complexes cationiques est la presence de deux groupes amides convergents qui, en solution, peuvent favoriser des interactions de liaisons hydrogenes assistees par des charges avec des molecules hotes heteroaromatiques appropriees, telles des nucleobases. Mots-cles : complexe organique du platine(II), hote organometallique, complexe dinucleaire, N-methylbenzamide. [Traduit par la Redaction], Introduction There is great interest in the study of synthetic receptors for the selective binding of nucleobases (1, 2), owing to their many important functional roles in biological systems, e.g., [...]

The utility of (-)-sparteine-mediated directed ortho metalation (DoM) has been investigated in stereoselective preparation of planar chiral ferrocenes derived from 1,1'-N,N,N',N'-tetraisopropylferrocenedicarboxamide (5). In the synthesis of [C.sub.2]-symmetric analogs of 5, the protocol (base, solvent, and two-step DoM) was found to be crucial for obtaining high enantio- and diastereo-selectivities of the products. A variety of highly enantioenriched mono and doubly functionalized derivatives of 5 have been synthesized. The synthetic applications of these compounds as chiral ligands in asymmetric alkylation of aldehydes and asymmetric palladium-catalyzed allylic substitutions have been demonstrated. Key words: directed ortho metalation, stereoselective deprotonation, ferrocene ligands, asymmetric catalysis. On a etudie l'utilite de l'ortho metallation dirigee (oMD) orientee par la (-)-sparteine, dans la preparation stereoselective de ferrocenes chiraux planaires derives du 1,1'-N,N,N',N'-tetraisopropylferrocenedicarboxamide (5). Dans la synthese d'analogues de symetrie [C.sub.2] du compose 5, on a trouve que le protocole experimental (base, solvant et oMD en deux etapes) est crucial si on veut obtenir des valeurs elevees d'enantio- et de diastereo-selectivites des produits. On a pu synthetiser avec un degre d'enantioenrichissement eleve une grande variete de derives du compose 5 mono- et di-fonctionnalises avec un degre d'enantioenrichissement eleve. On a demontre l'utilite synthetique de ces composes, en particulier comme ligands chiraux dans l'alkylation asymetrique d'aldehydes et dans les substitutions allyliques asymetriques catalysees par le palladiium. Mots cles : ortho metallation dirigee, deprotonation stereoselective, ligands ferrocenes, catalyse asymetrique. [Traduit par la Redaction], The disclosure, with an interesting socio-chemical history, of the correct structure of ferrocene over half a century ago constituted a landmark achievement that heralded an entirely new theme of organometallic [...]

A facile and simple method for the preparation of 3,4-dialkyl-3,4-dihydro-2H-1,3-benzoxazin-2-ones or naphthoxazin-2-ones in high yields from aminoalkylphenols and aminoalkylnaphthols is described. The reactions of the products obtained with organolithium and Grignard reagents were studied, and a method for the preparation of N-[1-2-hydroxyphenyl)alkyl]-N-alkylamides, which are of pharmaceutical interest, from benzoxazinones was developed. A possible reaction mechanism is also proposed. The relative configuration of chiral products was determined from conformational analysis of [sup.1]H NMR spectra. Key words: benzoxazinones, naphthoxazinones, organometallic reagents, amide preparation, aminoalkylphenols.

A range of Pt-diimine complexes possessing fluoroalkyl and hydrofluoroalkyl ligands were synthesized from the readily prepared [Pt(diimine)[Me.sub.2]] complexes and the appropriate iodofluoroalkane. For complexes with diimine ligands containing substituents in the 2, 6-positions of the aryl group, Pt(II) complexes were obtained due to in situ reductive elimination of MeI, while for complexes with diimine ligands of smaller steric demands (possessing substituents in the 3,5-positions or the 4-position), Pt(IV) complexes were obtained. Attempts to convert the Pt(IV) complexes to the desired Pt(II) species via reductive elimination of MeI, methane, or ethane resulted in either no reaction or degradation of the starting complex. Fluoroalkyl(methyl) platinum(II) complexes were then converted to the fluoroalkyliodoplatinum(II) complexes via addition of [I.sub.2] or by reaction with aq HI. Several complexes have been characterized crystallographically. Key words: fluoroalkyl, organometallic synthesis, structure, platinum.