Felix H. Cano

Indenyl complexes of ruthenium(II). Crystal structure of [Ru(CO)(PPh3)2(η5-C9H7)]ClO4·12CH2Cl2

Abstract The compound [RuCl(PPh3)2(η5-C9H7)] (I) has been made in high yield by reaction of [RuCl2(PPh3)3] with indene and potassium hydroxide in ethanol and its reactions have been examined. Complex I reacts with appropriate nucleophiles to give the complexes [RuX(PPh3)2(η5-C9H7)] (X = H, CH3, I, SnCl3, C2Ph) and [RuCl(dppe)(η5-C9H7)]. Heating of complex I with methanol in a sealed tube leads to the elimination of the indenyl group and decarbonylation of methanol. Cationic complexes of formulae [RuL(PPh3)2(η5-C9H7)]ClO4 (L = CH3CN, 2-ClC6H4CN, CH2CHCN, 1,2-(CN)2C6H4, C2H4(CN)2, N2H4, CNBut, CO, CCHPh, and C2H4) and [Ru(L-L)PPh3(η5-C9H7)]ClO4 (L-L = 2,5-norbornadiene (nbd), tetrafluorobenzobarrelene (tfb), ethylenediamine (en), propylenediamine (pn), biimidazole (Hbim), 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen)) are obtained by treatment of complex I with the appropriate ligand and sodium perchlorate in methanol. Reaction of the vinylideneruthenium complex [Ru(η1-CCHPh) (PPh3)2(η5-C9H7)]ClO4 with oxygen gives [Ru(CO)(PPh3)2(η5-C9H7)]ClO4. The structure of [Ru(CO)(PPh3)2(η5-C9H7)]ClO4· 1 2 CH2Cl2 has been determined by X-ray diffraction. The space group is P 1 with lattice constants a 18.5513(14), b 12.9165(5), and c 9.6898(5) A, and α 80.942(5), β 104.998(7) and γ 111.130(4)°. Final R and Rw factors are 0.039 and 0.043, respectively, for the 6836 observed data (3σ(I) criterion). The metal is bonded to an indenyl group through the five-membered ring, and hexacoordination of the ruthenium atom is completed by two triphenylphosphine ligands and a carbonyl group.

Rhodium(I) complexes with bis(pyrazolyl)methane ligands. Crystal structure of [Rh(COD)(CH2(Pz)2)]ClO4·12 C2H4Cl2

The synthesis and properties of neutral and cationic complexes of general formulae [{RhCl(diolefin)}2(CH2(pz)2)], [Rh(CO)2 (CH2(pz)2)][RhCl2(CO)2], (Rh(diolefin)(CH2(pz)2)]ClO2, [{Rh(diolefin)(PPh3)}2(CH2(pz)2)](ClO4)2, [Rh(CO)2(CH2(pz)2)]ClO4 and [Rh(CO)(CH2(pz)2)(PPh3)]ClO4 are described. The NMR spectra of [Rh(COD)(CH2(pz)2)]ClO4 complexes are discussed. X-ray structural analysis of [Rh(COD)(CH2(Pz)2)]ClO4 · 12C2H4Cl2 is presented; the final R factor is 0.061 for 2436 observed data, recorded with Cu-Kα, not corrected for absorption and with the sample inside a capillary. The Rh atom presents a distorted square planar coordination in a mononuclear arrangement. The COD ring has a twisted boat conformation, and the two halves of the CH2(Pz)2 moiety, which are quite similar to one another, form an angle of 47.2(4)°.

Tris(pyrazol-1-yl)methane-rhodium(I) and -iridium(I) complexes; cyrstal structure of [Rh(COD)(tpzm)][RhCl2(COD)]·3CHCl3

Abstract Fourteen new rhodium and iridium complexes of the tris(pyrazol-1-yl)methane (tpzm) ligand have been prepared. They are of the three types [MCl(diolefin)(tpzm)], [M(diolefin)(tpzm)]Clo 4 , and [M(diolefin)(tpzm)] [MCl 2 (diolefin)], where M is Rh I of Ir I and (diolefin) is a cyclic diolefin (1,5-cyclooctadiene, bicyclo-2,2,1-heptadiene, 5,6,7,8-tetrafluoro-1,4-dihydro-1,4-ethenoaphtalene, or 1,3-dimethyl-5,6,7-,8-tetrafluoro-1,4-dihydro-1,4-ethenonapthalene, or 1,3-dimethyl-5,6,7,8-tetrafluoro-1,4-dihydro-1,4-[9-methyletheno]-napthalene). Addition of [IrCl(COD)] 2 to [RhCl(COD)(tpzm)] gives the complex [Ir(COD)(tpzm)] [RhCl 2 (COD)] owing to the greater tendency of iridium to form five-coordinated species. The crystal structure of [Rh(COD)(tpzm)] [RhCl 2 (COD)] has been determined by X-ray diffraction. The space group is P 1 with a 12.4256(21), b 15.4113(25), c 12.0152(16) A, α 101.48(1), β 105.03(1) and λ 67.21(1)°. The complex exhibits an ionic dinuclear structure and crystallizes with six CHCl 3 molecules per unit cell. In the anion, the Rh(2) atom is in a square-planar arrangement and in the cation the coordination around Rh(1) is that of a distorted trigonal bipyramid. A careful 13 C and 1 H NMR spectra study has been carried out, with particular emphasis on the assignment of the pyrazole signals. The shifts induced by complexation (larger in the 1 H NMR spectra for iridium than for rhodium), the dynamics aspects, and the COD signals are discussed.

Glycosyl Inositol Derivatives Related to Inositolphosphoglycan Mediators: Synthesis, Structure, and Biological Activity

17 paginas, 12 figuras, 4 esquemas, 7 tablas.-- Supporting information for this article is available on the WWW under http://www.wiley-vch.de/home/chemistry/ or from the author.

The first asymmetric synthesis of polyfunctionalized 4H-pyrans via Michael addition of malononitrile to 2-acyl acrylates

Abstract Starting from (R)-2,3-O-isopropylideneglyceraldehyde, the first asymmetric synthesis of 4H-pyrans ( 4 ) has been developed; a detailed X-ray structural and stereochemical study has established as R the absolute configuration at the new stereocenter in compounds 4 .

Structure of bis-, tris- and tetrakispyrazolylborates in the solid state (sodium and potassium salts of tetrakispyrazolylborate by X-ray crystallography) and in solution (1H, 11B, 13C and 15N NMR)

Abstract The knowledge of the properties of pyrazolylborates has been considerably improved both in the solid state and in solution. The hydrates of the sodium and the potassium salts of tetrakis(l-pyrazolyl)borate crystallize in the space group C2/c, both salts being isomorphous. Regular pyrazole rings conform with a pseudosymmetry plane around a distorted tetrahedral boron atom. Chains along the b axis of two different octahedra of coordination, sharing water oxygens, are linked by H bonds. In solution, a careful 1H, 13C, 11B and 15N NMR study was carried out. The applicability of the rules used to assign H(3) versus H(5) and C(3) vcrsus C(5) in the case of pyrazolylborates was reevaluated. Only for tetrakis(1- pyrazolyl)borate were couplings observed with 1B in 1H, 3C and 5N resonances. The regularity of the properties of bis-, tris- and tetrakispyrazolylborates, allows the calculation of the spectral parameters of the still unknown tris-hydrido(1-pyrazolyl)borate, pzBH3−. Finally, the electronic properties, as measured by σp, of the substituents BH3−, pzBH2−, pz2BH− and pz3B− were estimated.

Development of methods for the synthesis of chiral, highly functionalized 2-amino-4-aryl-4H-pyrans

The development of new methods for the asymmetric synthesis of highly functionalized 2-amino-4-aryl-4 H -pyrans is described. Two alternative synthetic routes: the 1,4-conjugate addition of chiral β-ketoesters 3 or the N -acetoacetyl sultam 11 to arylidenemalononitriles 6 , and the Michael addition of malononitrile to enantiomerically pure α-acetylcinnamates 5 , have been designed. Depending upon the chiral auxiliary, the resulting 4 H -pyrans were obtained in low [(−)-menthol, (−)-borneol, (−)-ethyl lactate] to good (Oppolzers sultam) diastereomeric excesses. The absolute configuration at the new stereocenter in the minor isomer of compound 12a was determined as S by X-ray diffraction analysis. Reductive cleavage of 4 H -pyrans 12 with lithium aluminiun hydride yielded the enantiomerically pure or enriched alcohols 14 .

Complete energy profile of a chiral propeller compound: Tris-(2′-methylbenzimidazol-1′-yl) Methane (TMBM). Chromatographic resolution on triacetyl cellulose, x-ray structures of the racemic and one enantiomer, and dynamic NMR study

Abstract Tris-(2′-methylbenzimidazol-1 ′-y) methane (TMBM) presents an interesting example of propeller-like chirality, which is discussed according to Mislows and Dunitzs descriptions. Fortunately, the two most stable isomers (the three methyl groups “up”, i . e . on the same side of the methine proton, and two methyl groups “up” and the third one “down”) were present in the solid state, thus allowing the determination of their molecular structure by x-ray crystallography. The activation barrier which separates both isomers (9.8 kcal.mol −1 ) was determined by dynamic 1 H n.m.r., whereas that corresponding to enantiomers (28.5 kcal. mol −1 ) was determined kinetically by racemization, after pure enantiomers were resolved by chromatography on microcrystalline triacetyl cellulose. Both the racemic TMBM and its enantiomers crystallize with a larger number of water molecules, six and seven respectively, forming cyclic structures.

Cyclopentadienylruthenium complexes with chelating diamines and diolefins. Crystal structures of [Ru(nbd)(PPh3)(ϑ-C5H5)]ClO4 and [Ru{(η6-C6H5)Ph2PO}(η-C5H5)]ClO4. A new mode of coordination of triphenylphosphine oxide

Abstract Complexes of the general formulae [Ru(diamine)(PPh 3 )(η-C 5 H 5 )]ClO 4 and [Ru(diolefin)(PPh 3 )(η-C 5 H 5 )]ClO 4 (diamine = ethylenediamine (en), propylenediamine (pn), 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen), biimidazole (H 2 bim), bibenzimidazole (H 2 bbzim) and 2-(2′-pyridylbenzimidazole) (Hpybzim); diolefin = 2,5-norbornadiene (nbd), tetrafluorobenzobarrelene (tfb)) have been made by reaction of the complex RuCl(PPh 3 ) 2 (η-C 5 H 5 ) with the diamine or diolefin in the presence of sodiuim perchlorate. A single-crystal X-ray diffraction study of [Ru(nbd)(PPh 3 )(η-C 5 H 5 )]ClO 4 has been carried out. Crystals of the complex are monoclinic, space group P 2 1 / n , with a 18.0576(5), b 14.5070(3), c 10.3186(3) A; β 103.20(6)°. The structure was solved by Patterson synthesis using 4209 observed reflections (2σ( I ) criterion) and refined to a R factor of 0.040. Reaction of RuCl(PPh 3 ) 2 (η-C 5 H 5 ) with oxygen in the presence of sodium perchlorate leads to oxidation of the coordinated triphenylphospine ligands giving the complex [Ru{(η 6 -C 6 H 5 )Ph 2 PO}η-C 5 H 5 )]ClO 4 . In order to establish the structural identity of this compound a single-crystal X-ray diffraction study has been made. Crystals of this complex are monoclinic, space group P 2 1 / c , with a 10.818(5), b 9.4480(3), c 21.0036(19) A; β 90.246(6)°. The structure was solved by Patterson synthesis using 3819 observed reflections (3σ( I ) criterion) and refined to a R factor of 0.036. The ruthenium atom is coordinated in a sandwich fashion by the cyclopentadienyl group and a phenyl ring of the triphenylphosphine oxide ligand. The synthesis of new heteronuclear ruthenium(II)-rhodium(I) complexes of formulae [(η-C 5 H 5 )(Ph 3 P)-Ru(μ-bim)RhY 2 ] x and (η-C 5 H 5 )(Ph 3 P)Ru(μ-bbzim)RhY 2 (Y = CO, Y 2 = diolefin) is also described.

Asymmetric syntheses of 1-amino-2-phenyl(alkyl)cyclopropanecarboxylic acids by diastereoselective cyclopropanation of highly functionalized monochiral olefines

Abstract Monochiral α-benzamidocinnamic esters of N-methylephedrine or mandelic derivatives and benzylidene or alkylidene diketopiperazines, all obtained from oxazolones, react with diazomethane to give moderate to high diastereomeric excesses (d.e.) of pyrazoline derivatives which, after photolysis and acid hydrolysis of the resulting cyclopropyl compounds, gave (1R, 2R)-, (1S, 2S)-or (1S, 2R)-1-amino-2-phenyl(alkyl)cyclopropanecarboxylic acids. The enantiomerically pure dipeptide of the (1R, 2R) enantiomer with S-proline was also obtained by selective cleavage of the diketopiperazine moiety. The structure of all compounds has been assessed by NMR studies and y X-ray crystallography and analysis of an intermediate spiroderivative.