Delia Bautista

Effects of diphosphine structure on aurophilicity and luminescence in Au(I) complexes

The effects of diphosphine flexibility and bite angle on the structures and luminescence properties of Au(I) complexes have been investigated. A range of diphosphines based on heteroaromatic backbones [bis(2-diphenylphosphino)phenylether (dpephos), 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (xantphos), and 4,6-bis(diphenylphosphino)dibenzofuran (dbfphos)] has been used to prepare mono- and digold derivatives. A clear relationship between the presence of aurophilic contacts and the emission properties of dinuclear complexes has been observed, with one of the complexes studied, [Au(2)Cl(2)(micro-xantphos)], exhibiting luminescence thermochromism.

New palladium(II) and platinum(II) complexes with 9-aminoacridine: structures, luminiscence, theoretical calculations, and antitumor activity.

The new complexes [Pd(dmba)( N10-9AA)(PPh 3)]ClO 4 ( 1), [Pt(dmba)( N9-9AA)(PPh 3)]ClO 4 ( 2), [Pd(dmba)( N10-9AA)Cl] ( 3), and [Pd(C 6F 5)( N10-9AA)(PPh 3)Cl] ( 4) (9-AA = 9-aminoacridine; dmba = N,C-chelating 2-(dimethylaminomethyl)phenyl) have been prepared. The crystal structures have been established by X-ray diffraction. In complex 2, an anagostic C-H...Pt interaction is observed. All complexes are luminescent in the solid state at room temperature, showing important differences between the palladium and platinum complexes. Complex 2 shows two structured emission bands at high and low energies in the solid state, and the lifetimes are in agreement with excited states of triplet parentage. Density functional theory and time-dependent density functional theory calculations for complex 2 have been done. Values of IC 50 were also calculated for the new complexes 1- 4 against the tumor cell line HL-60. All of the new complexes were more active than cisplatin (up to 30-fold in some cases). The DNA adduct formation of the new complexes synthesized was followed by circular dichroism and electrophoretic mobility. Atomic force microscopy images of the modifications caused by the complexes on plasmid DNA pB R322 were also obtained.

Synthesis of a Palladium(IV) Complex by Oxidative Addition of an Aryl Halide to Palladium(II) and Its Use as Precatalyst in a CC Coupling Reaction

and the two isomers of complex 2.[*] Prof. Dr. J. Vicente, Prof. Dr. A. Arcas, M. Sc. F. Juli-HernndezGrupo de Qumica OrganometlicaDepartamento de Qumica Inorgnica, Facultad de QumicaUniversidad de Murcia, Aptdo. 4021, 30071 Murcia (Spain)E-mail: jvs1@um.esHomepage: http://www.um.es/gqo/Dr. D. BautistaSAI, Universidad de Murcia, Aptdo. 4021, 30071 Murcia (Spain)Supporting information for this article is available on the WWWunder http://dx.doi.org/10.1002/anie.201102214.

Novel bis-C,N-cyclometalated iridium(III) thiosemicarbazide antitumor complexes: interactions with human serum albumin and DNA, and inhibition of cathepsin B.

A series of new organoiridium(III) complexes [Ir(N-C)(2)(N-S)]Cl (HN-C = 2-phenylpyridine (Hppy), N-S = methyl thiosemicarbazide (1), phenyl thiosemicarbazide (2) and naphtyl thiosemicarbazide (3)) have been synthesized and characterized. The crystal structure of (1) has been established by X-ray diffraction, showing the thiosemicarbazide ligand bound to the iridium atom as N,S-chelate. The cytotoxicity studies show that they are more active than cisplatin (about 5-fold) in T47D (breast cancer) at 48 h incubation time. On the other hand, very low resistance factors (RF) of 1-3 in A2780cisR (cisplatin-resistant ovarian carcinoma) at 48 h were observed (RF ≈ 1). Ir accumulation in T47D cell line after 48 h continuous exposure for complexes 1-3 are higher than that corresponding to cisplatin (about 10 times). The complexes 1-3 bind strongly to HSA with binding constants of about 10(4) M(-1) at 296 K, binding occurring at the warfarin site I for 2. Complexes 2 and 3 are also capable of binding in the minor groove of DNA as shown by Hoechst 33258 displacement experiments. Furthermore, complex 2 is also a good cathepsin B inhibitor (an enzyme implicated in a number of cancer related events), being the enzyme reactivated by cysteine.

Quantitative synthesis and full characterization of the first isolated and stable pincer palladium(IV) complexes. Quantitative and regioselective synthesis of the C–X (X = Cl, Br) reductive elimination products

The pincer complexes [Pd(O(1),N(1),C(1)-L)X], where X = Cl, Br and L is the monoanionic ligand resulting from deprotonation of the acetyl methyl group of the monoketal of 2,6-diacetylpyridine (dap), react with excess of Cl(2) or Br(2) affording, quantitatively, the Pd(IV) complexes [Pd(O(1),N(1),C(1)-L)X(3)], which have been characterized by X-ray diffraction, and their decomposition that quantitatively affords the reductive elimination products L-X has been studied.

Asymmetric synthesis of ferrocenylazido alcohols and their derivatization to novel chiral ferrocenyl-thiazoline ligands with C2-symmetry

Abstract The synthesis of previously unreported chiral ferrocenyl-thiazoline ligands is described. (R)-2-Azido-1-ferrocenylethanol 3 and (R,R)-1,1′-bis(2-azido-1-hydroxyethyl)ferrocene 10, available by enantioselective borane reduction of α-azidoacetyl ferrocene 1 and 1,1′-bis(2-azidoacetyl)ferrocene 2, respectively, were converted into the corresponding ferrocenyl thiazolines by a three-step sequence involving catalytic hydrogenation, acylation and cyclization promoted by Lawessons reagent. New chiral ferrocene-thiazolines with C2-symmetry were obtained either from (R)-2-azido-1-ferrocenylethanol 3 and diacyl chlorides or from (R,R)-1,1′-bis(2-azido-1-hydroxyethyl)ferrocene 10 and monoacyl chlorides.

Mono- and Dinuclear Ag(I), Au(I), and Au(III) Metallamacrocycles Containing N-Heterocyclic Dicarbene Ligands

Ag(I) dicarbene complexes [Ag(m)(L(n))m]X(m) (L(n) = Im(Me)(CH2)(n)Im(Me), Im(Me) = N-methylimidazol-N-yl-2-ylidene; n = 3, X = PF6, m = 2; n = 6-8, 10, X = AgBr2, m = 1, 2) were prepared by reacting Ag2O with 1 equiv of the corresponding bisimidazolium salt [H2L(n)]A2 (A = PF6, Br). The dibromoargentates react with 1 equiv of AgTfO to afford [Ag(m)(L(n))m](TfO)m (m = 1, 2). The room temperature transmetalation reaction of [Ag(m)(L(n))m][AgBr2]m (n = 3, 5, 6-8, 10) with [AuCl(SMe2)] and AgTfO (L(n):Au:TfO = 1:1:1) affords [Au2(μ-L(n))2](TfO)2 (n = 3, 5, 10), or mixtures of [Au(κ(2)-L(n))]TfO (main product for n = 7) and [Au2(μ-L(n))2](TfO)2 (main product for n = 6, 8). At room temperature, the equilibrium between [M2(μ-L(n))2](TfO)2 and [M(κ(2)-L(n))]TfO is fast for M = Ag, but slow for M = Au, in the NMR time scale. When n ≥ 7 and M = Ag or Au, the equilibrium is shifted toward the mononuclear complexes in the order 8 > 10 > 7, which proves that the (CH2)8 linker has the optimal length for trans chelation. Correspondingly, the high-temperature metalation of [H2L(n)]Br2 (n = 8, 10) with 1 equiv of [AuCl(SMe2)] and excess of NaAcO, affords [Au(κ(2)-L(n))]Br with a small amount of [Au2(μ-L(n))2]Br2. If AgTfO is added to the reaction mixture, [Au(κ(2)-L(8))]2[AgBr3] is isolated instead of the desired triflate, which can be obtained by reacting the mixture of [Au(κ(2)-L(8))]Br and [Au2(μ-L(8))2]Br2 with AgTfO. [Au(κ(2)-L(10))]TfO was isolated after thermal conversion of [Au2(μ-L(10))2](TfO)2. [Au(κ(2)-L(8))]TfO reacts with I2 to give trans-[AuI2(κ(2)-L(8))]TfO, which is the first Au(III) complex containing a trans-spanning bidentate ligand. We have determined the crystal structures of complexes [Ag2(μ-L(3))2](PF6)2, [Ag(κ(2)-L(7))]TfO, [Au2(μ-L(3))2](TfO)2, [Au(κ(2)-L(8))]Br, [Au(κ(2)-L(8))]2[AgBr3], and trans-[AuI2(κ(2)-L(8))]TfO.

Unexpected formation of 2,1-benzisothiazol-3-ones from oxathiolano ketenimines: a rare tandem process.

A rare one-pot reaction, a tandem [1,5]-H shift/1,5 electrocyclization/[3 + 2] cycloreversion process, leading from N-[2-(1,3-oxathiolan-2-yl)]phenyl ketenimines to 1-(beta-styryl)-2,1-benzisothiazol-3-ones and ethylene, is disclosed and mechanistically unraveled by means of a computational DFT study. The two latter stages of the tandem process are calculated to occur in a single mechanistic step via a transition structure of pseudopericyclic characteristics.

Persistent radical effect in the intramolecular addition of benzylic radicals onto ketenimines: selective cross-coupling of α-(indol-2-yl)benzyl radicals with the 1-cyano-1-methylethyl radical

The intramolecular addition of benzylic radicals, generated from benzyl phenyl selenides by the action of tris(trimethylsilyl)silane and AIBN or AIBMe, onto neighbouring ketenimine functions is studied. The persistent α-(indol-2-yl)benzyl radicals, resulting from such cyclization processes, undergo cross-coupling with the tert-alkyl radicals arising from the thermal decomposition of the AIBN or AIBMe initiators to give, respectively, 3-(1H-indol-2-yl)propiononitriles 10 or propanoates 14. A rare spiropentacyclic compound 17 containing two indole fragments also resulted from one of these radical reactions. The crystal and molecular structures of 10d and 17 have been solved by X-ray analysis.

Homoleptic tris-cyclometalated platinum(IV) complexes: a new class of long-lived, highly efficient 3LC emitters

The synthesis of meridional and facial isomers of tris-cyclometalated Pt(IV) complexes, [Pt(C^N)3]OTf, where C^N is a C-deprotonated 2-phenylpyridine-based ligand or 1-phenylpyrazole, is reported for the first time. The facial isomers exhibit high-energy emissions from essentially 3LC excited states, characterized by lifetimes of hundreds of microseconds and quantum yields up to 0.49 at room temperature in fluid solution, the highest ever found for Pt(IV) complexes. Stern–Volmer studies demonstrate the high sensitivity of the facial isomers toward oxygen and their electrochemical characterization reveals large redox gaps and a strong oxidizing character in the excited state.