Francesca Lianza

Facile cycloplatination of nitrogen compounds. Crystal structure of the cycloplatinated Schiff's base tetralone derivative PtCl{(cyclohexyl)NC(CH2)3C6H3 (CO)

Abstract Facile preparative methods for the cycloplatination of benzo[ c ]quinoline ( 1 ), two Schiffs base tetralone compounds, R 1 NC(CH 2 ) 3 C 6 H 4 (R 1 = cyclohexyl ( 2 ), CH 2 ( p -C 6 H 4 OCH 3 ) ( 3 )), and 8-methylquinoline ( 4 ), are given. An extension of these methods leads readily to new cycloplatination chemistry involving use of 1 or 3 or quinoline-8-carboxaldehyde and the cycloplatinated phosphite complex [Pt(μ-Cl){(R 2 O) 2 POC 6 H 4 ]] 2 , R 2 = Et, Ph, to give the complexes Pt(NO 3 )( CN ){P(OPh)(OR) 2 }, where ( CN ) denotes the cycloplatinated nitrogen-ligand. The molecular structure of PtCl{(cyclohexyl)NC(CH 2 ) 3 C 6 H 3 ](CO) has been determined by X-ray diffraction.

Chemistry of PdII complexes containing both BINAP (2′2′-bis(diphenylphosphino)binaphthyl) and a η3-pinene or -allyl ligand. NMR studies on [Pd(η3-C10H15){S(−)BINAP}] (CF3SO3). The crystal structure of [Pd(η3-C10H15)(4,4′-dimethylbipyridine)](CF3SO3)

Abstract One and two-dimensional 1H, 13C and 31P NMR studies on palladium(II) complexes containing η3-C10H15 or η3-C4H7 allyl and S(−)BINAP ligands are reported. Details of the three-dimensional solution structure for [Pd(η3C10H15) {S(−)BINAP}(CF3SO3) based on 1H-2D NOESY and molecular modelling calculations are presented. The structure for the model β-pinene allyl complex [Pd(η3-C10H15)(4,4′-dimethylbipyridine)]CF3SO3) has been determined by an X-ray diffraction study, which reveals that the CH2 terminal allyl carbon is significantly displaced from the N-Pd-N plane.

Synthetic methodologies for tripodal phosphines. The preparation of MeSi(CH2PPh2)3 and n-BuSn(CH2PPh2)3 and a comparison of their rhodium(I) and ruthenium(II) coordination chemistry. The X-ray crystal structures of [Rh(NBD){n-BuSn(CH2PPh2)3}](OTf) and [Rh(NBD){MeSi(CH2PPh2)3}](OTf)☆

Abstract The preparation of the new tripodal ligands MeSi(CH2PPh2)3 (Si-triphos) and n-BuSn(CH2PPh2)3 (Sn-triphos) and their complexes of rhodium(I) of the type [Rh(NBD)(tripod)](OTf) (NBD  norbornadiene, OTf  triflate) and of ruthenium(II) of the type [Ru(O2CCF3)2(tripod)], is reported. The coordination chemistry of the new tripodal phosphines, and in particular that of Sn-triphos, differs significantly from that of MeC(CH2PPh2)3 (triphos). A comparison of the X-ray structure of [Rh(NBD)(triphos)](OTf) with those of the new complexes [Rh(NBD)(Sn-triphos)](OTf) and [Rh(NBD)(Si-triphos)](OTf) shows that the steric requirements of the ligands RE(CH2PPh2)3 (E  C, Si and Sn), increas from the carbon to the tin compound. The coordination chemistry of ruthenium(II) indicates that, relative to triphos, Sn-triphos displays an enhanced steric bulk which, however, is not sufficient to stabilize the mononuclear, five-coordinate dichloro complexes.

H3O2− bridging in a Pt(IV) nucleobase complex leading to infinite chains: trans, trans, trans-[Pt(NH3)2-(1-MeU)2(H3O2)]n(NO3)·(4H2O)n (1-MeU = 1-methyluracilate)

Abstract The X-ray crystal structure determination of a Pt(IV) nucleobase complex, trans,trans,trans [Pt(NH3)2(1-MeU)2-(H3O2)]n(NO3)n·(4H2O)n (1-MeU = 1-methyluracilate-N3) is reported. The compound, obtained upon recrystallization of trans,trans,trans-[Pt(NH3)2(1-MeUH)2(OH)2](NO3)2 (1-MeUH = neutral l-methyluracil-N3) from water, crystallizes in the triclinic system, space group P-1 with two independent cations in the unit cell: a = 7.3023(8), b = 10.1470(20, c = 13.4220(20) A α = 78.800(17), β = 83.580(9), γ = 78.930(10)°, V = 954.6(3) A 3 , Z = 2 . Description of its solid state structure as a H3O2− compound rather than a genuine mixed H2O,OH− complex is based on the presence of very short H bonds of 2.450(6) A between the oxygens of axial aqua and hydroxo ligands of adjacent Pt(IV) cations, leading to infinite chains.

Preparation and X-ray crystal structures of Li4[Hg2(edta)2] · 8H2O and Ba2[Hg2(teta)2] · 9H2O (teta = N,N,N′,N′-diaminobutanetetraacetate)

Abstract The Hg(II) complexes of the N,N,N′,N′ -tetraacetate of 1,2-deaminoethane (edta) and 1,4-diaminobutane (teta) were crystallized from concentrated aqueous solutions. The first ligand gave crystals of Li 4 Hg 2 (edta) 2 ] · 8H 2 O. Its single crystal X-ray structure determination (triclinic space group P ¯ with a = 9.369)(3), b = 9.354(3), c = 11.584(4) A, α = 67.90(2), β = 67.50(2), γ = 80.42(3)° and Z = 1) showed that each mercury(II) is mainly bound to six donor atoms of the same ligand anion. The coordinated anionic is strained and leaves sufficient space for a seventh donor atom, i.e. a coordinated oxygen atom of the nearest complex ion bound with a much shorter Hg-O distance. The second ligand gave Ba 2 [Hg 2 (teta) 2 ] · 9H 2 O (space group C / c with a = 17.840(2), b = 15.243(2), c = 18.962(6), β = 113.84(1)° and Z = 4) containing two equivalent ligand anions giving the simplest polymeric structure, i.e. a dimer. These results are in agreement with the data obtained from equilibrium studies.

Formation and X-ray crystal structure analysis of a Pt(IV) complex of 1-methylthymine, obtained through Au(III) treatment of a Pt(II)complex

Abstract The crystal structure of cis,cis-[(NH3)2Pt(1-MeT)2(OH)(H2O)]AuCI4·H2O, where 1-MeT is the anion of 1- methylthymine, C6H7N2O2, is reported. The compound contains both heterocyclic bases bound to Pt via the N3 positions, the two nucleobase ligands being in a head-to-head orientation. It represents the first X-ray structurally characterized example of a Pt(IV) species of thymine. The compound crystallizes in the space group P 1 with unit cell dimensions a=8.435(4), b=11.884(3), c=12.869(7) A, a=97.28(3), β=91.66(5), γ=110.66(5), V= 1193(2) A3.

Feroxidin, a novel 1-methyltetralin derivative isolated from cape aloe☆

Abstract The structure and the preferred conformation of feroxidin ( 1 ) are determined by spectroscopic methods ( 1 HNMR, NOE, CD). The absolute configuration is deduced from chiroptical data. Feroxidin represents the first 1-methyltetralin occurring in plants.

Synthesis and molecular structure of optically active oxazolidine complexes of platinum(II) and palladium(II)

Abstract Two series of optically active complexes of the type trans-PtCl2(C2H4)(oxazolidine) (3) and trans-PdCl2(PPh3)(oxazolidine) (4) oxazolidine= NHCH(p-ClC 6 H 4 )OCH 2 C HR (R=a Me; b Et; c Bui; d Bz; e Ph) have been prepared and characterized. The synthesis involves metal promoted cyclization of the optically active Schiffs bases p-ClC6H4CHNCH(R)CH2OH and proceeds for both metal centers in high chemical and optical yield (diastereomeric excesses of 78–96%). Attack of the oxygen at the imine carbon results in preferential formation of complexed five-membered rings which have the cis-geometry with respect to the C-2 and C-5 substituents. The solid-state structures for 3b and 4c have been determined by X-ray diffraction. Both structures reveal expected coordination spheres with the MCl2 (C2H4 or PPh3) fragment occupying a pseudo trans position with respect to the oxazolidine C-2 C-5 substituents. This observation, combined with solution 2-D NOESY measurements, is used to rationalize the observed diastereomeric excesses. Crystallographic data for the complexes are as follows: 3b, orthorhombic, space group P212121a=7.003(1), b=16.573(1), c=29.088(4) A, V=3376.1(7) A3, Z=8; 4c orthorhombic space group P212121a=11.921(2) b=12.241(1) c=21.107(2) A, V=3080(1) A3, Z=4. The structures have been refined to R factors of 0.04 and 0.05, respectively.

Simultaneous binding of soft and hard metals to a pyrimidine nucleobase: Preparation and X-ray structure of [(en)Pd(1-MeT)2Na2](NO3)2·H2O (1-MeT = 1-methylthymine anion)

Abstract The crystal structure of [(en)Pd(1-MeT)2Na2](NO3)2·H2O, where 1-MeT = 1-methylthymine anion, C6H7N2O2, is reported. The compound crystallizes in the monoclinic system, space group P21/c with a = 8.203(1), b = 20.908(5), c = 13.644(5) A, β = 98.35(2)°, V = 2316(2) A3. Pd binding is through N3 of the two 1-MeT rings. The two Na+ are coordinated to two O4 and two O2 oxygens of the 1-MeT rings, respectively. The compound represents the first structurally characterized example of M,M′2 stoichiometry derived from a cis-a2ML2 compound.