Study of Organic Rankine Cycles for Waste Heat Recovery in Transportation Vehicles

Regulations for ICE-based transportation in the EU seek carbon dioxide emissions lower than 95 g CO2/km by 2020. In order to fulfill these limits, improvements in vehicle fuel consumption have to be achieved. One of the main losses of ICEs happens in the exhaust line. Internal combustion engines transform chemical energy into mechanical energy through combustion; however, only about 15-32% of this energy is effectively used to produce work, while most of the fuel energy is wasted through exhaust gases and coolant. Therefore, these sources can be exploited to improve the overall efficiency of the engine. Between these sources, exhaust gases show the largest potential of Waste Heat Recovery (WHR) due to its high level of exergy. Regarding WHR technologies, Rankine cycles are considered as the most promising candidates for improving Internal Combustion Engines. However, the implementation of this technology in modern passenger cars requires additional features to achieve a compact integration and controllability in the engine. While industrial applications typically operates in steady state operating points, there is a huge challenge taking into account its impact in the engine during typical daily driving profiles. This thesis contributes to the knowledge and characterization of an Organic Rankine Cycle coupled with an Internal Combustion Engine using ethanol as working fluid and a swash-plate expander as expansion machine. The main objective of this research work is to obtain and quantify the potential of Organic Rankine Cycles for the use of residual energy in automotive engines. To do this, an experimental ORC test bench was designed and built at CMT (Polytechnic University of Valencia), which can be coupled to different types of automotive combustion engines. Using these results, an estimation of the main variables of the cycle was obtained both in stationary and transient operating points. A potential of increasing ICE mechanical efficiency up to 3.7% could be reached at points of high load installing an ORC in a conventional turbocharged gasoline engine. Regarding transient conditions, a slightly simple and robust control based on adaptive PIDs, allows the control of the ORC in realistic driving profiles. High loads and hot conditions should be the starting ideal conditions to test and validate the control of the ORC in order to achieve high exhaust temperatures that justify the feasibility of the system. In order to deepen in the viability and characteristics of this particular application, some theoretical studies were done. A 1D model was developed using LMS Imagine.Lab Amesim platform. A potential improvement of 2.5% in fuel conversion efficiency was obtained at the high operating points as a direct consequence of the 23.5 g/kWh reduction in bsfc. To conclude, a thermo-economic study was developed taking into account the main elements of the installation costs and a minimum Specific Investment Cost value of 2030 €/kW was obtained. Moreover, an exergetic study showed that a total amount of 3.75 kW, 36.5% of exergy destruction rate, could be lowered in the forthcoming years, taking account the maximum efficiencies considering technical restrictions of the cycle components.Las normativas anticontaminantes para el transporte propulsado por motores de combustión interna alternativos en la Unión Europea muestran límites de emisión menores a 95 g CO2/km para el año 2020. Con el fin de cumplir estos límites, deberán ser realizadas mejoras en el consumo de combustible en los vehículos. Una de las principales pérdidas en los Motores de Combustión Interna Alternativos (MCIA) ocurre en la línea de escape. Los MCIA transforman la energía química en energía mecánica a través de la combustión; sin embargo, únicamente el 15-32% de esta energía es eficazmente usada para producir trabajo, mientras que la mayor parte es desperdiciada a través de los gases de escape y el agua de refrigeración del motor. Por ello, estas fuentes de energía pueden ser utilizadas para mejorar la eficiencia global del vehículo. De estas fuentes, los gases de escape muestran un potencial mayor de recuperación de energía residual debido a su mayor contenido exergético. De todos los tipos de Sistemas de Recuperación de Energía Residual, los Ciclos Rankine son considerados como los candidatos más prometedores para mejorar la eficiencia de los MCIA. Sin embargo, la implementación de esta tecnología en los vehículos de pasajeros modernos requiere nuevas características para conseguir una integración compacta y una buena controlabilidad del motor. Mientras que las aplicaciones industriales normalmente operan en puntos de operación estacionarios, en el caso de los vehículos con MCIA existen importantes retos teniendo en cuenta su impacto en el modo de conducción cotidianos. Esta Tesis contribuye al conocimiento y caracterización de un Ciclo Rankine Orgánico acoplado con un Motor de Combustión Interna Alternativo utilizando etanol como fluido de trabajo y un expansor tipo Swash-plate como máquina expansora. El principal objetivo de este trabajo de investigación es obtener y cuantificar el potencial de los Ciclos Rankine Orgánicos (ORC) para la recuperación de la energía residual en motores de automoción. Para ello, una instalación experimental con un Ciclo Rankine Orgánico fue diseñada y construida en el Instituto Universitario "CMT - Motores Térmicos" (Universidad Politécnica de Valencia), que puede ser acoplada a diferentes tipos de motores de combustión interna alternativos. Usando esta instalación, una estimación de las principales variables del ciclo fue obtenida tanto en puntos estacionarios como en transitorios. Un potencial de mejora en torno a un 3.7 % puede ser alcanzada en puntos de alta carga instalando un ORC en un motor gasolina turboalimentado. Respecto a las condiciones transitorias, un control sencillo y robusto basado en PIDs adaptativos permite el control del ORC en perfiles de conducción reales. Las condiciones ideales para testear y validar el control del ORC son alta carga en el motor comenzando con el motor en caliente para conseguir altas temperaturas en el escape que justifiquen la viabilidad de estos ciclos. Para tratar de profundizar en la viabilidad y características de esta aplicación particular, diversos estudios teóricos fueron realizados. Un modelo 1D fue desarrollado usando el software LMS Imagine.Lab Amesim. Un potencial de mejora en torno a un 2.5% en el rendimiento efectivo del motor fue obtenido en condiciones transitorias en los puntos de alta carga como una consecuencia directa de la reducción de 23.5 g/kWh del consumo específico. Para concluir, un estudio termo-económico fue desarrollado teniendo en cuenta los costes de los principales elementos de la instalación y un valor mínimo de 2030 €/kW fue obtenido en el parámetro de Coste Específico de inversión. Además, el estudio exergético muestra que un total de 3.75 kW, 36.5 % de la tasa de destrucción total de exergía, podría ser reducida en los años futuros, teniendo en cuenta las máximas eficiencias considerando restricciones técnicas en los componentes del ciclo.Les normatives anticontaminants per al transport propulsat per motors de combustió interna alternatius a la Unió Europea mostren límits d'emissió menors a 95 g·CO2/km per a l'any 2020. Per tal d'acomplir aquests límits, s'hauran de realitzar millores al consum de combustible dels vehicles. Una de les principals pèrdues als Motors de combustió interna alternatius (MCIA) ocorre a la línia d'escapament. Els MCIA transformen l'energia química en energia mecànica a través de la combustió; però, únicament el 15-32% d'aquesta energia és usada per produir treball, mentre que la major part és desaprofitada a través dels gasos d'escapament i l'aigua de refrigeració del motor. Per això, aquestes fonts d'energia poden ser utilitzades per millorar l'eficiència global del vehicle. Considerant aquestes dues fonts d'energia, els gasos d'escapament mostren un potencial major de recuperació d'energia residual debut al seu major contingut exergètic. De tots els tipus de Sistemes de Recuperació d'Energia Residual, els Cicles Rankine són considerats com els candidats més prometedors per millorar l'eficiència dels MCIA. No obstant, la implementació d'aquesta tecnologia en els vehicles de passatgers moderns requereix un desenvolupament addicional per aconseguir una integració compacta i una bona controlabilitat del motor. Mentre que les aplicacions industrials normalment operen en punts d'operació estacionaris, en el cas dels vehicles amb MCIA hi han importants reptes a solucionar tenint en compte el funcionament en condicions variables del motor i el seu impacte en la manera de conducció quotidiana del usuari. Aquesta Tesi contribueix al coneixement i caracterització d'un Cicle Rankine Orgànic (ORC) acoblat amb un motor de combustió interna alternatiu (MCIA) utilitzant etanol com a fluid de treball i un expansor tipus Swash-plate com a màquina expansora. El principal objectiu d'aquest treball de recerca és obtenir i quantificar el potencial dels ORCs per a la recuperació de l'energia residual en motors d'automoció. Per aconseguir-ho, una instal·lació experimental amb un ORC va ser dissenyada i construïda a l'Institut "CMT- Motores Térmicos" (Universitat Politècnica de València). Esta installació pot ser acoblada a diferents tipus de MCIAs. Mitjançant assajos experimentals en aquesta installació, una estimació de les principals variables del cicle va ser obtinguda tant en punts estacionaris com en punts transitoris. Un potencial de millora al voltant d'un 3.7% pot ser aconseguida en punts d'alta càrrega instal·lant un ORC acoblat a un motor gasolina turboalimentat. Pel que fa a les condicions transitòries, un control senzill i robust basat en PIDs adaptatius permet el control del ORC en perfils de conducció reals. Les condicions ideals per a testejar i validar el control de l'ORC són alta càrrega al motor començant amb el motor en calent per aconseguir altes temperatures d'escapament que justifiquen la viabilitat d'aquests cicles. Per tractar d'aprofundir en la viabilitat i característiques d'aquesta aplicació particular, diversos estudis teòrics van ser realitzats. Un model 1D va ser desenvolupat usant el programari LMS Imagine.Lab Amesim. Un potencial de millora al voltant d'un 2.5% en el rendiment efectiu del motor va ser obtingut en condicions transitòries en els punts d'alta càrrega com una conseqüència directa de la reducció de 23.5 g/kWh al consum específic. Per concloure, un estudi termo-econòmic va ser desenvolupat tenint en compte els costos dels principals elements de la installació i un valor mínim de 2030 €/kW va ser obtingut en el paràmetre del Cost Específic d'Inversió. A més, l'estudi exergètic mostra que un total de 3.75 kW, 36.5% de la taxa de destrucció total d'exergia, podria ser recuperat en un pròxim, considerant restriccions tècniques en els components del cicle i tenint en compte les màximes eficiències que es poden aconseguir.Royo Pascual, L. (2017). Study of Organic Rankine Cycles for Waste Heat Recovery in Transportation Vehicles [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84013TESI

Dichloro(methyl) silyl-substituted cyclopentadienyl titanium complexes

The synthesis of (C5H4)(SiMeCl2)(SiMe3) is described. The reaction of a dichloromethane solution of this compound with one equivalent of titanium tetrachloride leads to the monocyclopentadienyl complex [TiCl3{η5-C5H4(SiMeCl2)}]. Treatment of this complex with the lithium amides LiN(SiMe3)2 and LiNHtBu affords [TiCl2{N(SiMe3)2}{η5-C5H4(SiMeCl2)}] and [TiCl2{η5-C5H4[SiMeCl(η-NtBu)]}], respectively. Alkylation of the trichlorotitanium derivative with 1.5 equivalents of Mg(CH2C6H5)2(THF)2 leads to the tribenzyl derivative [Ti(CH2C6H5)3{η5-C5H4(SiMeCl2)}]. Hydrolysis of the trichloro- and tribenzyl-complexes leads to the μ-oxo dititanium compounds [TiX2μ-{η5-C5H4(η-OSiMeCl)}]2 (X=Cl, CH2Ph). All of the new complexes were characterized by elemental analysis and NMR spectroscopy.We are grateful to the DGICYT (Project PB-92-0178-C) and CAM (I + D 0034/94) for financial support.\ud B.R. acknowledges Universidad de Alcalá de Henares for support provided (Project 042/95

Synthesis and reactivity of new mixed dicyclopentadienyl Group 4 metal complexes with the doubly bridged bis(dimethylsilanediyl)-cyclopentadiene-(η5-cyclopentadienyl) ligand

The monocyclopentadienyl titanium complex [Ti{(C5H4)(SiMe2)2(η5-C5H3)} Cl3] 3 and the dichloro mixed dicyclopentadienyl Group 4 metal complexes [M(η5-C5R5){(C5H4)(SiMe2)2(η5-C5H3)} Cl2] (R=H; M=Ti 4, Zr 5, Hf 6; R=Me; M=Ti 7) containing the doubly bridged bis(dimethylsilanediyl)-cyclopentadiene-(η5-cyclopentadienyl) ligand were prepared in high yields by reaction of the monolithium salt Li[(C5H4)(SiMe2)2(C5H3)] 2 with equimolar amounts of TiCl4 or the monocyclopentadienyl complexes [Cp′MCl3], respectively. Reactions of the chloro complexes with various alkylating agents afforded the chloroalkyl [M(η5-C5H5){(C5H4)(SiMe2)2(η5-C5H3)}ClR] (M=Ti; R=Me 8, Et 9; M=Zr, R=Me 10, Et 11, CH2Ph 12; M=Hf, R=CH2Ph 13) and dialkyl [M(η5-C5R5){(C5H4)(SiMe2)2(η5-C5H3)}Me2] (M=Ti; R=H 14, Me 15; M=Zr; R=H 16, compounds. Formation of the heterodinuclear complex [Zr(η5-C5H5)Cl2(η5-C5H3)(SiMe2)2(η5-C5H3)Ti(NMe2)3] 17 with amine elimination was observed by 1H-NMR spectroscopy when complex 5 was reacted with Ti(NMe2)4. The catalytic activity of compounds 3–5 for ethylene polymerization has been studied using MAO as cocatalyst

Transition metal complexes with functionalized silyl-substituted cyclopentadienyl and related ligands: synthesis and reactivity

Interest in modifying transition metal complexes using substituted cyclopentadienyl rings has been stimulated in the last years by their potential synthetic and catalytic applications in different processes. This review will feature mono- and dicyclopentadienyl-transition metal complexes containing silyl-cyclopentadienyl and related indenyl and fluorenyl ligands. All of these compounds contain silyl-substituted functionalities which are able to coordinate the metal center or used to introduce such a type of ligating moieties. The synthesis and chemical behaviour of these types of compounds are strongly emphasized. Compounds discussed are all those containing silicon-bound substituents which include: (a) hydrosilyl (Si–H); (b) halosilyl (Si–X); oxosilyl (Si–O); (c) amino– and amido–silyl (Si–N); (d) alkyl– and alkenyl–silyl (Si–C) and (d) boron–silyl (Si–B) compounds. A brief remark on their most significant structural characteristics is also included.Financial support by DGICYT (Project PB97-0776) is gratefully acknowledged

Reactivity of the dinuclear fulvalene cyclopentadienyl zirconium cationic species \ud [{Zr(η5-C5H5)}2(μ-CH2)(μ-Cl)(μ-η5-C5H4-η5-C5H4)]+ with isocyanides and carbon monoxide: insertion reactions, spectroscopic characterization and synthetic aspects

The dinuclear cationic zirconium compound [{Zr(η5-C5H5)}2(μ-CH2)(μ-Cl)(μ-η5-C5H4-η5-C5H4)][BMe(C6F5)3] 1 reacts in dichloromethane at −78 °C with three equivalents of RNC (R=tBu, 2,6-Me2C6H3) via insertion into the Zr-μ-methylene bond to give the new zirconium cationic species [{Zr(η5-C5H5)}2(Cl)(CNtBu){μ-[η2-CN(tBu)-CH2-η2-CN(tBu)}(μ-η5-C5H4-η5-C5H4)][BMe(C6F5)3] 2 and [{Zr(η5-C5H5)}2(Cl){CN(2,6-Me2C6H3)}[μ-η2-{CN(2,6-Me2C6H3)}-CH2-η2-{CN(2,6-Me2C6H3)}](μ-η5-C5H4-η5-C5H4)][BMe(C6F5)3] 3, whereas reaction with CO affords the ketene compound [{Zr(η5-C5H5)}2(μ-Cl){μ-OC(CH2)}(μ-η5-C5H4-η5-C5H4)][BMe(C6F5)3] 4. The new complexes reported herein were characterized by elemental analysis and IR and NMR spectroscopy.Financial support by DGICYT (Project PB97-0776)\ud is gratefully acknowledged. E.R. acknowledges MECFPI\ud for the award of Fellowshi

Synthesis and characterization of η5-tetramethylcyclopentadienyl hydrido-and -chloro-silyl-η1 -amido zirconium complexes

The silylated tetramethylcyclopentadienes C5Me4(SiMeCl2)(SiMe3) (1) and C5Me4H(SiMeHCl) (3) were isolated by reaction of\ud their corresponding trimethylsilyltetramethylcyclopentadienyl and tetramethylcyclopentadienyl lithium salts with SiMeCl3 and\ud SiMeHCl2, respectively. Reaction of a toluene suspension of ZrCl4 with one equivalent of 1 afforded the monocyclopentadienyl\ud zirconium complex [Zr(h5\ud -C5Me4SiMeCl2)Cl3] (2). Reaction of 3 with NH2\ud t\ud Bu gave C5Me4H[SiMeH(NHt\ud Bu)] (4) which was further\ud metallated to give Li2[C5Me4SiMeH(Nt\ud Bu)] (5), used to prepare the silyl-h1\ud -amido zirconium derivative [Zr(h5\ud -C5Me4SiMeH-h1\ud -\ud Nt\ud Bu)Cl2] (6) by reaction with ZrCl4(THF)2. Chlorination of 6 with BCl3 afforded [Zr(h5\ud -C5Me4SiMeCl-h1\ud -Nt\ud Bu)Cl2] (12).\ud Alkylation and amidation of 6 and 12 provided the corresponding disubstituted [Zr(h5\ud -C5Me4SiMeH-h1\ud -Nt\ud Bu)R2] (R /Me 7,\ud CH2Ph 8, NMe2 9) and [Zr(h5\ud -C5Me4SiMeCl-h1\ud -Nt\ud Bu)Me2] (13) and monosubstituted [Zr(h5\ud -C5Me4SiMeH-h1\ud -Nt\ud Bu)ClR] (R /\ud C6F5 10, N(SiMe3)2 11) and [Zr(h5\ud -C5Me4SiMeCl-h1\ud -Nt\ud Bu)Cl{N(SiMe3)2}] (14). All of the new compounds reported were\ud characterized by elemental analyses and NMR spectroscopy.We thank Ministerio de Ciencia y Tecnología for\ud support of this work (Project MCyT-MAT2001-1309\ud and predoctoral fellowship to A.B.V

Insertion of carbon dioxide and isocyanide into tantalum-amide and tantalum-methyl bonds

The methyl–amide complex [TaCp*(NtBu)Me(NMe2)] (1a) was isolated by reaction of the chloro–methyl [TaCp*(NtBu)MeCl] complex with LiNMe2. Reaction of the mono-amide compounds [TaCp*(NtBu)XY] (X=NMe2, Y=Me (1a); X=NHtBu, Y=Me (1b), Cl (1c)) with CO2 gives the η2-carbamate derivatives [TaCp*(NtBu)(η2-O2CX)Y] (X=NMe2, Y=Me (2a); X=NHtBu, Y=Me (2b), Cl (2c)). A similar reaction with the di-amide complex [TaCp*(NtBu)(NHtBu)2] (1d) gives the di-carbamate derivative [TaCp*(NtBu){η2-O2C(NHtBu)}{η1-O2C(NHtBu)] (2d). Reaction of the methyl–carbamate (2a) with isocyanide CNAr (Ar=2,6-Me2C6H3) gives the η2-iminoacyl–η1-carbamate complex [TaCp*(NtBu){η2-C(Me)NAr}{η1-O2C(NMe2)] (3a). Formation of the related compound [TaCp*(NtBu){η2-C(Me)NAr}{η1-O2C(NHtBu)}] (3b) was only detected by NMR spectroscopy in C6D6 or CDCl3 whereas the reaction of 2b in hexane gives the η1-iminoacyl–η2-carbamate complex [TaCp*(NtBu){η1-C(Me)NAr}{η2-O2C(NHtBu)}] (3b′). All of the new compounds were characterized by elemental analysis and 1H- and 13C-NMR spectroscopy

Oxo and imido/imido exchange and C-H activation reactions based on pentamethylcylopentadienyl imido tantalum complexes

Reactions of [TaCp*Cl4] with two, three and four equivalents of LiNHt Bu give the halo- and amido-imido complexes [TaCp*Cl2(Nt Bu)] (1a), [TaCp*Cl(Nt Bu)(NHt Bu)] (2) and [TaCp*(Nt Bu)(NHt Bu)2] (3), respectively. The related complex [TaCp*Cl2{N(2,6-Me2C6H3)}] (1b) is prepared by a similar reaction using two equivalents of Li[NH(2,6-Me2C6H3)]. Complex 3 can be transformed into 2 and further into 1a by reaction with SiClMe3. Complex 1a reacts with CNt Bu to give the 18-electron adduct [TaCp*Cl2(Nt Bu)(CNt Bu)] (4) whereas addition of excess CN(2,6-Me2C6H3) results in reductive elimination of the carbodiimide t BuN C N(2,6-Me2C6H3) (5) to give [TaCp*Cl2{CN(2,6-Me2C6H3)}3]. However complex 1b does not react with any of the isocyanide ligands. Both complexes 1a and 1b react with PhCHO undergoing imido/oxo exchange to give the imines PhCH NR (R=t Bu, 2,6-Me2C6H3 (6)) and dimeric [TaCp*Cl2(O)]2 or trimeric [(TaCp*Cl)3(m2-Cl)(m2-O)3(m3-O)] oxo-complexes, whereas only 1a reacts with CO2, PhCH NR% (R%=Ph, Me) and (2,6-Me2C6H3)N C Nt Bu producing t BuN CO, PhCH Nt Bu and t BuN C Nt Bu, respectively and the corresponding oxo or imido tantalum derivative. None of the complexes reacts with CO or NCR (R=Me, Ph). The complex [TaCp*Me(Nt Bu)(NHt Bu)] activates C–H bonds when heated in benzene and toluene affording [TaCp*Ph(Nt Bu)(NHt Bu)] (7) and a mixture of [TaCp*(m-MeC6H4)(Nt Bu)(NHt Bu)] 8a and [TaCp*(pMeC6H4)(Nt Bu)(NHt Bu)] (8b). All of the reported organic compounds and tantalum complexes were characterized by 1 H- and 13C-NMR spectroscopyThe authors acknowledge DGICYT (project PB97-0776) for financial support and J.S.N. acknowledges MEC for a fellowship

Synthesis and characterization of η5-cyclopentadienyl-silylallyl niobium and tantalum complexes

Reaction of the disilylcyclopentadiene 1,1-[SiMe2(CH2CHdouble bond; length as m-dashCH2)]2C5H4 with NbCl5 gave the new allylsilyl-substituted monocyclopentadienyl niobium complex [Nb{η5-C5H4SiMe2(CH2CHdouble bond; length as m-dashCH2)}Cl4]. This compound was reacted with LiNHtBu or NH2tBu to give the imido derivative [Nb{η5-C5H4SiMe2(CH2CHdouble bond; length as m-dashCH2)}(NtBu)Cl2], which was further alkylated to the imido alkyl complexes [Nb{η5-C5H4SiMe2(CH2CHdouble bond; length as m-dashCH2)}(NtBu)R2] (R = Me, CH2Ph) and [Nb{η5-C5H4SiMe2(CH2CHdouble bond; length as m-dashCH2)}(NtBu)Cl (CH2Ph)]. Reaction of the imido complexes with the corresponding lithium cyclopentadienides gave the dicyclopentadienyl-imido complexes [M(η5-C5R5){η5-C5H4SiMe2(CH2CHdouble bond; length as m-dashCH2)}(NtBu)Cl] (M = Nb, Ta; R = H, Me). Metallocene dichlorides [M(η5-C5R5){η5-C5H4SiMe2(CH2CHdouble bond; length as m-dashCH2)}Cl2] (M = Nb, Ta; R = H, Me) were easily prepared by reduction with Na/Hg and simultaneous transmetallation of [Ta(η5-C5R5)Cl4] with Li[C5H4SiMe2(CH2CHdouble bond; length as m-dashCH2)] and of [Nb{η5-C5H4SiMe2(CH2CHdouble bond; length as m-dashCH2)}Cl4] with Li(C5R5). All of the new compounds have been characterized by elemental analysis, and IR and NMR spectroscopy.Financial support of our work by MCyT (Project MAT2001-1309) is gratefully acknowledged

Synthesis and characterization of methyl-phenyl-substituted cyclopentadienyl zirconium complexes

The trisubstituted methyl-phenyl-silyl-cyclopentadienes [Me-Ph-C5H3(SiMe2X)] (X = Me, Cl, NHt-Bu) and [(Me-Ph-C5H3)2SiMe2] and the lithium salts Li2[Me-Ph-C5H2(SiMe2Nt-Bu)] and Li2[(Me-Ph-C5H2)2SiMe2] have been isolated by conventional methods and characterized by NMR spectroscopy. Desilylation of [Me-Ph-C5H3(SiMe3)] with ZrCl4(SMe2)2 gave the monocyclopentadienyl complex [Zr(η5-1-Ph-3-Me-C5H3)Cl3]. The ansa-metallocene [Zr{(η5-2-Me-4-Ph-C5H2)SiMe2(η5-2-Ph-4-Me-C5H2)}Cl2] was obtained from the mixture of isomers formed by transmetallation of Li2[(Me-Ph-C5H2)2SiMe2] to ZrCl4 and characterized as the meso-diastereomer by X-ray diffraction methods. Similar transmetallation of Li2[Me-Ph-C5H2(SiMe2Nt-Bu)] gave the silyl-η-amido complex [Zr{η5-2-Me-4-Ph-C5H2(SiMe2-η-Nt-Bu)}Cl2] that was further alkylated to give [Zr{η5-2-Me-4-Ph-C5H2(SiMe2-η-Nt-Bu)}R2] (R = Me, CH2Ph) and used as a catalyst precursor, activated with MAO, for ethene and propene polymerization. All of the new compounds were characterized by elemental analysis and NMR spectroscopy.Ministerio de Educación, Cultura y Deport