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Tomas Cuenca - One of the best experts on this subject based on the ideXlab platform.

  • Novel enantiopure cyclopentadienyl Ti(IV) oximato compounds as potential anticancer agents
    Journal of inorganic biochemistry, 2015
    Co-Authors: Isabel De La Cueva-alique, Tomas Cuenca, Laura Muñoz-moreno, Yosra Benabdelouahab, Benelita T. Elie, Mohammed Amin El Amrani, Marta E. G. Mosquera, María Contel, Ana M. Bajo, Eva Royo
    Abstract:

    The synthesis and characterization of new enantiopure cyclopentadienyl Titanium oximato compounds (S,R)-[(η(5)-C5H5)Ti{к(2)NO,(R)NH·HCl}Cl2] (R=Ph (phenyl) 1a·HCl, Bn (benzyl) 1b·HCl, 2-pic (2-picolyl) 1c·HCl), (S,R)-[(η(5)-C5H5)TiCl2{к(2)NO,(Ph)NH}] (1a) and (S,R)-[(η(5)-C5H5)2TiCl{к(2)NO,(R)NH}] (R=Ph 2a, Bn 2b, 2-pic 2c), along with studies on their behavior in D2O at different pD values are reported. The structure of previously described ammonium-oxime (2S,5R)-{NOH,(Bn)NH·HCl} (b·HCl) and novel Titanium Derivative 1a have been determined by single crystal X-ray crystallography. The effect of the compounds on cytotoxicity, cell adhesion and migration of the androgen-independent prostate cancer PC-3 cells has been assessed. Compounds 2b and 2c are more cytotoxic than additive doses of titanocene dichloride and free oxime proligand, probing the synergistic effect of these novel compounds. The cytotoxicity of 2b and 2c has been further evaluated against human renal Caki-1, colon DLD-1 and triple negative breast MDA-MB-231 cancer cell lines. The activity found for 2c on PC-3 and Caki-1 is higher than that of highly active Titanocene Y (bis-[(p-methoxybenzyl)cyclopentadienyl]Titanium(IV) dichloride), while showing selectivity against renal cancer when compared to a non-tumorigenic human renal (HEK-293T) cell line. Compounds 2b and especially 2c are apoptotic in Caki-1 cancer cell lines. Cell adhesion and wound-healing assays confirmed that Derivatives 1c·HCl, 2b and 2c affect the adhesion and migration patterns of the PC-3 cell line. Interactions of the novel compounds with plasmid (pBR322) DNA have also been studied, showing that the oximato Ti(IV) Derivatives have a weak or no interaction with DNA at physiological pH.

  • Early transition metal Derivatives stabilised by the phenylenediamido 1,2-C6H4(NCH2tBu)2 ligand: Synthesis, characterisation and reactivity studies: Crystal structures of [Ta{1,2-C6H4(NCH2tBu)2}2Cl] and [Zr{(1,2-C6H4(NCH2tBu)2}(NMe2)(μ-NMe2)]2
    Polyhedron, 2009
    Co-Authors: Vanessa Tabernero, Tomas Cuenca, Marta E. G. Mosquera, Carmen Ramírez De Arellano
    Abstract:

    Abstract Li 2 [1,2-C 6 H 4 (NCH 2 t Bu) 2 ] reacts with one equiv of [TiCl 4 (THF) 2 ] in refluxing toluene to give the chelate compound [Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }Cl 2 (THF)] ( 1 ), isolated as a black product, while the reaction of the dilithio diamido salt with one equiv of [ZrCl 4 (THF) 2 ] in refluxing toluene affords the dinuclear zirconium Derivative [Zr{1,2-C 6 H 4 (NCH 2 t Bu) 2 }Cl(THF)(μ-Cl)] 2 ( 2 ), obtained as an orange solid. Treatment of the dilithio diamido salt with TaCl 5 in a 2:1 molar ratio in toluene yields [Ta{1,2-C 6 H 4 (NCH 2 t Bu) 2 } 2 Cl] ( 3 ) as a red product. The reaction of 1,2-C 6 H 4 (NHCH 2 t Bu) 2 with [Zr(NMe 2 ) 4 ] in toluene at room temperature affords the dinuclear zirconium complex [Zr{1,2-C 6 H 4 (NCH 2 t Bu) 2 }(NMe 2 )(μ-NMe 2 )] 2 ( 4 ). The dibenzyl Derivative [Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }(CH 2 Ph) 2 ] ( 5 ) is obtained by the reaction of 1 with 2 equiv of Mg(CH 2 Ph)Cl at −78 °C. Compound 1 reacts with the lithium amide reagent LiN(SiMe 3 ) 2 to afford [Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }Cl{N(SiMe 3 )}] ( 6 ). The μ-oxo Titanium Derivative [(Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }{CH 2 Ph}) 2 (μ-O)] 7 is precipitated when compound 5 is maintained in solution. The tendency of these compounds to coordinate donor ligands and their reactivity with Lewis acid reagents are described. All compounds were analytically and spectroscopically characterised and the molecular structures of the diamine 1,2-C 6 H 4 (NHCH 2 t Bu) 2 and the complexes 3 and 4 were established by single-crystal X-ray diffraction studies. The lack of correlation between the degree of metallacycle folding and phenylene ring distortion is observed in the solid state structures. The performance of precursors 1 , 3 and 5 were evaluated in ethylene polymerisation upon activation with B(C 6 F 5 ) 3 , methylaluminoxane (MAO) and sMAO as cocatalysts, with very modest activities.

  • alkylmono cyclopentadienyl Titanium complexes containing the 2 2 methylenebis 6 tert butyl 4 methylphenoxido ligand studies on the nature of the catalytic species present in α olefin polymerisation processes
    European Journal of Inorganic Chemistry, 2007
    Co-Authors: Marta Gonzalezmaupoey, Tomas Cuenca, Obis Castaño, Luis Manuel Frutos, Eberhardt Herdtweck, Bernhard Rieger
    Abstract:

    The mono(alkyl)bis(phenoxido)Titanium complexes [TiR'(η 5 -C 5 R 5 )(η 2 -mbmp)] [R = H, R' = Me (4), CH 2 Ph (5), Ph (6), CH 2 SiMe 3 (7); R = Me, R' = Me (8), CH 2 Ph (9), CH 2 SiMe 3 (10); η 2 -mbmp = 2,2'-methylenebis(6-tent-butyl-4-methyl-phenoxido)] have been prepared in good yields by reaction of the appropriate alkylating reagent with the corresponding chlorido(cyclopentadienyl)bis(phenoxido)Titanium Derivative. Compound 6 reacts in toluene with traces of water to afford the μ-oxidoTitanium complex {Ti(η 5 -C 5 H 5 )(η 2 -mbmp}} 2 (μ-O) (11). Compounds 8, 9 and 11 have been characterised by single-crystal X-ray crystallography, and density functional calculations have been performed in order to elucidate the energetic and structural properties of these compounds. The activity of these complexes in the presence of methylaluminoxane (MAO), B(C 6 F 5 ) 3 or [Ph 3 C][B(C 6 F 5 ) 4 ] as co-catalysts in the polymerisation of propylene and styrene has been studied. In an effort to model the nature of the catalytic species generated from these precursors, the reactions of the mono(cyclopentadienyl)bis(phenoxido)chlorido- and -alkylTitanium Derivatives with Lewis acids were examined. B(C 6 F 5 ) 3 reacts with the neutral complexes [TiR'(η 5 -C 5 R 5 )(η 2 -mbmp)] by abstraction of the alkyl group R' to give the highly stable species [Ti(η 5 -C 5 H 5 )(η 2 -mbmp)][MeB(C6F5)3] (12), (Ti(η 5 -C 5 H 5 )(η 2 -mbmp)][(PhH 2 )B(C 6 F 5 ) 3 ] (13), [Ti(η 5 -C5Me5)(η 2 -mbmp)][MeB(C6F5)3] (14) and [Ti(η 5 -C 5 Me 5 )(η 2 -mbmp)][(PhCH2)B(C 6 F 5 ) 3 ] (15), which are inactive in propylene and styrene polymerisation. In contrast, the reaction between the neutral alkyl Derivatives and [CPh 3 ][B(C 6 F 5 ) 4 ] affords species that are active in α-olefin polymerisation. Treatment of the mono(chlorido) compound [TiCl(η 5 -C 5 H 5 )(η 2 -mbmp)] with 1 equiv. of AlMe 3 affords the methyl Derivative 4 as essentially the only reaction product. When an excess of AlMe 3 is used, transmetallation reactions of the bis(phenoxido) ligand from Titanium to aluminium are observed. Reactions of the bis(phenol) mbmpH 2 with AlMe 3 or AlClMe 2 yield [AlMe(mbmp)] 2 (16) and [AlCl(mbmp)] 2 (17).

  • Group 4 ansa-metallocenes in oxidation state (III): synthesis, characterization, and chemical behavior. Crystal structure of [[.eta.5:.eta.5-(C5H4)2Si(CH3)2]TiCl(PMe2Ph)]
    Organometallics, 1991
    Co-Authors: Rafael Gómez, Tomas Cuenca, Pascual Royo, Maria Angela Pellinghelli, Antonio Tiripicchio
    Abstract:

    Two new dimeric Titanium (III) and zirconium (III) ansa-metallocenes {[(Me 2 SiCp 2 )MCl] 2 } (M=Ti(2a), Zr(2b)) were synthesized by reducing the dichlorometallocenes with Na/Hg. The same reduction of the Titanium Derivative in the presence of PMe 2 Ph led to the monomeric Titanium (III) complex [(Me 2 SiCp 2 )TiCl(PMe 2 Ph)] (3), which was also obtained by addition of PMe 2 Ph to 2a. Alkylation of 3 led to the Titanium (III) alkyls [(Me 2 SiCp 2 )TiR(PMe 2 Ph)] (R=Me (4), CH 2 SiMe 3 (5)). 4 was also obtained by reduction of [(Me 2 SiCp 2 )TiClMe] (6) with Na/Hg in the presence of PMe 2 Ph

Rafael Gómez - One of the best experts on this subject based on the ideXlab platform.

  • Cationic species derived from the η1-amidosilyl-η5-cyclopentadienyl dimethyl Titanium complex. Crystal structure of [Ti{η5-C5H4SiMe2[η1-N(2,6-Me2C6H3)]}{CH2B(C6F5)2}(C6F5)]
    Journal of Organometallic Chemistry, 1999
    Co-Authors: Rafael Gómez, Pilar Gómez-sal, Pedro A. Del Real, Pascual Royo
    Abstract:

    Abstract Reactions of the η 5 -cyclopentadienyl-η 1 -amido dimethyl Titanium Derivative [Ti{η 5 -C 5 H 4 SiMe 2 [η 1 -N(C 6 H 3 Me 2 )]}Me 2 ] ( 1 ) with tris(pentafluorophenyl)borane B(C 6 F 5 ) 3 in hexane at room temperature yield a thermally stable bright yellow microcrystaline solid identified by elemental analysis as [Ti{η 5 -C 5 H 4 SiMe 2 [η 1 -N(C 6 H 3 Me 2 )]}Me{MeB(C 6 F 5 ) 3 }] ( 2 ). A solution of 1 in CD 2 Cl 2 at −78°C affords the ion-pair complex 2 , while in C 6 D 6 it is slowly converted into the new neutral complex [Ti{η 5 -C 5 H 4 SiMe 2 [η 1 -N(C 6 H 3 Me 2 )]}{CH 2 B(C 6 F 5 ) 2 }(C 6 F 5 )] ( 3 ). Complex 3 is the unique product obtained after stirring compound 2 or a mixture of complex 1 and B(C 6 F 5 ) 3 in toluene or benzene for 12 h at room temperature. The molecular structure of complex 3 has been determined by diffraction methods.

  • Cationic species derived from the h-amidosilyl-h-cyclopentadienyl dimethyl Titanium complex. Crystal structure of [Ti{h-C5H4SiMe2[h-N(2,6-Me2C6H3)]}{CH2B(C6F5)2}(C6F5)]
    1999
    Co-Authors: Rafael Gómez, Pilar Gómez-sal, Pedro A. Del Real, Pascual Royo
    Abstract:

    Reactions of the h-cyclopentadienyl-h-amido dimethyl Titanium Derivative [Ti{h-C5H4SiMe2[h-N(C6H3Me2)]}Me2] (1) with tris(pentafluorophenyl)borane B(C6F5)3 in hexane at room temperature yield a thermally stable bright yellow microcrystaline solid identified by elemental analysis as [Ti{h-C5H4SiMe2[h-N(C6H3Me2)]}Me{MeB(C6F5)3}] (2). A solution of 1 in CD2Cl2 at −78°C affords the ion-pair complex 2, while in C6D6 it is slowly converted into the new neutral complex [Ti{h-C5H4SiMe2[h-N(C6H3Me2)]}{CH2B(C6F5)2}(C6F5)] (3). Complex 3 is the unique product obtained after stirring compound 2 or a mixture of complex 1 and B(C6F5)3 in toluene or benzene for 12 h at room temperature. The molecular structure of complex 3 has been determined by diffraction methods. © 1999 Elsevier Science S.A. All rights reserved.

  • Group 4 ansa-metallocenes in oxidation state (III): synthesis, characterization, and chemical behavior. Crystal structure of [[.eta.5:.eta.5-(C5H4)2Si(CH3)2]TiCl(PMe2Ph)]
    Organometallics, 1991
    Co-Authors: Rafael Gómez, Tomas Cuenca, Pascual Royo, Maria Angela Pellinghelli, Antonio Tiripicchio
    Abstract:

    Two new dimeric Titanium (III) and zirconium (III) ansa-metallocenes {[(Me 2 SiCp 2 )MCl] 2 } (M=Ti(2a), Zr(2b)) were synthesized by reducing the dichlorometallocenes with Na/Hg. The same reduction of the Titanium Derivative in the presence of PMe 2 Ph led to the monomeric Titanium (III) complex [(Me 2 SiCp 2 )TiCl(PMe 2 Ph)] (3), which was also obtained by addition of PMe 2 Ph to 2a. Alkylation of 3 led to the Titanium (III) alkyls [(Me 2 SiCp 2 )TiR(PMe 2 Ph)] (R=Me (4), CH 2 SiMe 3 (5)). 4 was also obtained by reduction of [(Me 2 SiCp 2 )TiClMe] (6) with Na/Hg in the presence of PMe 2 Ph

Pascual Royo - One of the best experts on this subject based on the ideXlab platform.

  • Cationic species derived from the η1-amidosilyl-η5-cyclopentadienyl dimethyl Titanium complex. Crystal structure of [Ti{η5-C5H4SiMe2[η1-N(2,6-Me2C6H3)]}{CH2B(C6F5)2}(C6F5)]
    Journal of Organometallic Chemistry, 1999
    Co-Authors: Rafael Gómez, Pilar Gómez-sal, Pedro A. Del Real, Pascual Royo
    Abstract:

    Abstract Reactions of the η 5 -cyclopentadienyl-η 1 -amido dimethyl Titanium Derivative [Ti{η 5 -C 5 H 4 SiMe 2 [η 1 -N(C 6 H 3 Me 2 )]}Me 2 ] ( 1 ) with tris(pentafluorophenyl)borane B(C 6 F 5 ) 3 in hexane at room temperature yield a thermally stable bright yellow microcrystaline solid identified by elemental analysis as [Ti{η 5 -C 5 H 4 SiMe 2 [η 1 -N(C 6 H 3 Me 2 )]}Me{MeB(C 6 F 5 ) 3 }] ( 2 ). A solution of 1 in CD 2 Cl 2 at −78°C affords the ion-pair complex 2 , while in C 6 D 6 it is slowly converted into the new neutral complex [Ti{η 5 -C 5 H 4 SiMe 2 [η 1 -N(C 6 H 3 Me 2 )]}{CH 2 B(C 6 F 5 ) 2 }(C 6 F 5 )] ( 3 ). Complex 3 is the unique product obtained after stirring compound 2 or a mixture of complex 1 and B(C 6 F 5 ) 3 in toluene or benzene for 12 h at room temperature. The molecular structure of complex 3 has been determined by diffraction methods.

  • Cationic species derived from the h-amidosilyl-h-cyclopentadienyl dimethyl Titanium complex. Crystal structure of [Ti{h-C5H4SiMe2[h-N(2,6-Me2C6H3)]}{CH2B(C6F5)2}(C6F5)]
    1999
    Co-Authors: Rafael Gómez, Pilar Gómez-sal, Pedro A. Del Real, Pascual Royo
    Abstract:

    Reactions of the h-cyclopentadienyl-h-amido dimethyl Titanium Derivative [Ti{h-C5H4SiMe2[h-N(C6H3Me2)]}Me2] (1) with tris(pentafluorophenyl)borane B(C6F5)3 in hexane at room temperature yield a thermally stable bright yellow microcrystaline solid identified by elemental analysis as [Ti{h-C5H4SiMe2[h-N(C6H3Me2)]}Me{MeB(C6F5)3}] (2). A solution of 1 in CD2Cl2 at −78°C affords the ion-pair complex 2, while in C6D6 it is slowly converted into the new neutral complex [Ti{h-C5H4SiMe2[h-N(C6H3Me2)]}{CH2B(C6F5)2}(C6F5)] (3). Complex 3 is the unique product obtained after stirring compound 2 or a mixture of complex 1 and B(C6F5)3 in toluene or benzene for 12 h at room temperature. The molecular structure of complex 3 has been determined by diffraction methods. © 1999 Elsevier Science S.A. All rights reserved.

  • Group 4 ansa-metallocenes in oxidation state (III): synthesis, characterization, and chemical behavior. Crystal structure of [[.eta.5:.eta.5-(C5H4)2Si(CH3)2]TiCl(PMe2Ph)]
    Organometallics, 1991
    Co-Authors: Rafael Gómez, Tomas Cuenca, Pascual Royo, Maria Angela Pellinghelli, Antonio Tiripicchio
    Abstract:

    Two new dimeric Titanium (III) and zirconium (III) ansa-metallocenes {[(Me 2 SiCp 2 )MCl] 2 } (M=Ti(2a), Zr(2b)) were synthesized by reducing the dichlorometallocenes with Na/Hg. The same reduction of the Titanium Derivative in the presence of PMe 2 Ph led to the monomeric Titanium (III) complex [(Me 2 SiCp 2 )TiCl(PMe 2 Ph)] (3), which was also obtained by addition of PMe 2 Ph to 2a. Alkylation of 3 led to the Titanium (III) alkyls [(Me 2 SiCp 2 )TiR(PMe 2 Ph)] (R=Me (4), CH 2 SiMe 3 (5)). 4 was also obtained by reduction of [(Me 2 SiCp 2 )TiClMe] (6) with Na/Hg in the presence of PMe 2 Ph

Thorsten Krumpholz - One of the best experts on this subject based on the ideXlab platform.

  • Characterisation of the fibre/matrix adhesion with different microscopic analysing methods on natural fibre‐reinforced thermosets
    Macromolecular Materials and Engineering, 2000
    Co-Authors: Walter Michaeli, Michael Münker, Thorsten Krumpholz
    Abstract:

    Investigations of the fibre/matrix adhesion mechanisms with the application of butyl titanate as coupling agent cannot completely solve the effect of this Titanium Derivative. Different microscopic methods show that the formation of a fibre/matrix boundary layer with butyl titanate as resin additive does not take place. An improvement of the adhesion between fibre and matrix by improved chemical bonds cannot be responsible with this application of the coupling agent for the improved mechanical properties of the laminates. The atomic force microscopic results and the mechanical properties of the matrix with butyl titanate show that a modification of the stiffness of the matrix or the fibre/matrix interface with the application of the titanate does exist.

Carmen Ramírez De Arellano - One of the best experts on this subject based on the ideXlab platform.

  • Early transition metal Derivatives stabilised by the phenylenediamido 1,2-C6H4(NCH2tBu)2 ligand: Synthesis, characterisation and reactivity studies: Crystal structures of [Ta{1,2-C6H4(NCH2tBu)2}2Cl] and [Zr{(1,2-C6H4(NCH2tBu)2}(NMe2)(μ-NMe2)]2
    Polyhedron, 2009
    Co-Authors: Vanessa Tabernero, Tomas Cuenca, Marta E. G. Mosquera, Carmen Ramírez De Arellano
    Abstract:

    Abstract Li 2 [1,2-C 6 H 4 (NCH 2 t Bu) 2 ] reacts with one equiv of [TiCl 4 (THF) 2 ] in refluxing toluene to give the chelate compound [Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }Cl 2 (THF)] ( 1 ), isolated as a black product, while the reaction of the dilithio diamido salt with one equiv of [ZrCl 4 (THF) 2 ] in refluxing toluene affords the dinuclear zirconium Derivative [Zr{1,2-C 6 H 4 (NCH 2 t Bu) 2 }Cl(THF)(μ-Cl)] 2 ( 2 ), obtained as an orange solid. Treatment of the dilithio diamido salt with TaCl 5 in a 2:1 molar ratio in toluene yields [Ta{1,2-C 6 H 4 (NCH 2 t Bu) 2 } 2 Cl] ( 3 ) as a red product. The reaction of 1,2-C 6 H 4 (NHCH 2 t Bu) 2 with [Zr(NMe 2 ) 4 ] in toluene at room temperature affords the dinuclear zirconium complex [Zr{1,2-C 6 H 4 (NCH 2 t Bu) 2 }(NMe 2 )(μ-NMe 2 )] 2 ( 4 ). The dibenzyl Derivative [Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }(CH 2 Ph) 2 ] ( 5 ) is obtained by the reaction of 1 with 2 equiv of Mg(CH 2 Ph)Cl at −78 °C. Compound 1 reacts with the lithium amide reagent LiN(SiMe 3 ) 2 to afford [Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }Cl{N(SiMe 3 )}] ( 6 ). The μ-oxo Titanium Derivative [(Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }{CH 2 Ph}) 2 (μ-O)] 7 is precipitated when compound 5 is maintained in solution. The tendency of these compounds to coordinate donor ligands and their reactivity with Lewis acid reagents are described. All compounds were analytically and spectroscopically characterised and the molecular structures of the diamine 1,2-C 6 H 4 (NHCH 2 t Bu) 2 and the complexes 3 and 4 were established by single-crystal X-ray diffraction studies. The lack of correlation between the degree of metallacycle folding and phenylene ring distortion is observed in the solid state structures. The performance of precursors 1 , 3 and 5 were evaluated in ethylene polymerisation upon activation with B(C 6 F 5 ) 3 , methylaluminoxane (MAO) and sMAO as cocatalysts, with very modest activities.