Sandra S. Rodrigues

Synthesis of ferrocenyldiimine metal carbonyl complexes and an investigation of the Mo adduct encapsulated in cyclodextrin

Cr and Mo tetracarbonyl complexes bearing the diimine ligand N,N′-bis(ferrocenylmethylene)ethylenediamine (FcNN) have been prepared from the ligand and M(CO)6. Two isomeric forms of (FcNN)Mo(CO)4, corresponding to the cis,cis and cis,trans geometries with respect to the CN bonds of the free ligand, were shown to exist in a 1∶12.5 ratio by 1H NMR (NOE experiments). By contrast, only the trans,trans isomer is observed for the Cr complex (FcNN)Cr(CO)4. The compounds (FcNN)M(CO)4 show ferrocene-based irreversible oxidation processes that lead to the deposition of a film at the electrode surface. (FcNN)Mo(CO)4 was immobilised in permethylated β-CD (TRIMEB) by addition of the guest to a solution of TRIMEB in dichloromethane. Removal of the solvent led to the isolation of an inclusion compound with a 2∶1 host∶guest stoichiometry, as evidenced by powder X-ray diffraction, thermogravimetric analysis, FTIR and 13C CP MAS NMR spectroscopy. The electrochemical properties of (FcNN)Mo(CO)4 upon encapsulation are discussed.

Syntheses and dynamic NMR studies on 3-(1′-indenyl)propyl-N,N-bis(trimethylsylil)amine metal derivatives

Abstract The syntheses and characterisation of C 9 H 6 (X)(CH 2 ) 3 N(SiMe 3 ) 2 (X=H ( 2 ), SiMe 3 ( 4 ), Li ( 3 )) are described. The reactions of 4 with TiCl 4 , [TiCp*Cl 3 ] and NbCl 5 led to the isolation of [Ti{N(H)(CH 2 ) 3 C 9 H 6 SiMe 3 }Cl 3 ] ( 5 ), [TiCp*{N(H)(CH 2 ) 3 (C 9 H 6 SiMe 3 )}Cl 2 ] ( 8 ) and [Nb{N(CH 2 ) 3 (C 9 H 6 SiMe 3 )}Cl 3 ] 2 ·THF ( 9 ), respectively. The reaction of 3 with TiCl 4 led to the ansa -bridged indenyl-amido complex [Ti{η 5 :σ,π(C 9 H 6 )(CH 2 ) 3 N(SiMe 3 )}Cl 2 ] ( 7 ) and with [Mo(CO) 2 (CH 3 CH 2 CN) 2 (C 3 H 5 )Cl] gave [{η 5 -C 9 H 6 (CH 2 ) 3 N(SiMe 3 ) 2 }Mo(CO) 2 (C 3 H 5 )] ( 10 ). Two conformers, corresponding to the limit orientations of the allyl ligand ( endo and exo ) have been identified in solution, by NMR. The activation parameters for the slow endo / exo isomerisation process were determined.

Zirconium indenylamido complexes: synthesis and reactivity: Crystal structure of [Zr(Ind)2(NC3H6)2]

Abstract Reactions of [ZrInd(NMe2)3] (1) with Me3SiCl afforded [ZrInd(NMe2)2Cl] (2), [ZrInd(NMe2)Cl2] (3) and [ZrIndCl3]n (4) in high yields (≥90%). [ZrIndCl3(dme)] (5) was obtained either from 4 and dme or by a one-pot reaction from [ZrInd(NMe2)3], Me3SiCl and dme. Treatment of [ZrInd(NMe2)2Cl] with LiMe gave [ZrInd(NMe2)2Me] (6), and in similar reaction conditions [ZrInd2Me2] (10) was obtained from [ZrInd(NMe2)Cl2]. Whereas the reaction of 2 with LiN(H)tBu produced {[ZrInd(NMe2)2[N(H)tBu]} (7), the addition of LiN(H)tBu to [TiInd(NMe2)2Cl] afforded [Ti(NMe2)2(μ-NtBu)]2 (9) in quantitative yield. {TiInd(NMe2)2[N(H)tBu]} was identified by NMR as an intermediate in the synthesis of 9, and two isomeric forms corresponding to the parallel (8a) and perpendicular (8b) orientations of the indenyl and N(H)tBu ligands were characterised. The addition of an excess of azetidine to 1 gave [ZrInd2(NC3H6)2] (11), the molecular structure of which was determined by X-ray crystallography. Preliminary studies showed that 3–methylaluminoxane (MAO) polymerises ethylene and propylene, whereas [TiInd(NMe2)Cl2], 12–MAO, only polymerises ethylene.

Supramolecular arrangements of titanium dichloride ketimide complexes with Cp type ligands

The packing in titanium dichloride ketimide complexes with cyclopentadienyl type ligands is strongly dependent on the interactions formed by the two chloride ligands. In this study we report the influence in these interactions and the resulting supramolecular arrangements of the presence of different substituents in the Cp ring and also in the ketimide ligand. Both the characteristics of the individual molecules and the optimization of the intermolecular interactions result in supramolecular arrangements that range from the conventional 3-D arrays to more organized packings like linear and helicoidal chains. In this work we use our own crystallographic results [1] together with data retrieved in CSD [2].

Titanium indenyldimethylamido complexes: synthesis, characterisation and theoretical calculations. Crystal structure of [Ti(η5-Ind)(NMe2)Cl2]

Reactions of Ti(Ind)Cl3, 1, with LiNMe2 afforded the corresponding titanium indenyldimethylamido complexes Ti(Ind)(NMe2)Cl2, 2, Ti(Ind)(NMe2)2Cl, 3, and Ti(Ind)(NMe2)3, 4, depending on the reaction conditions. Treatment of 2 and 3 with LiMe yielded Ti(Ind)(NMe2)Me2, 5, and Ti(Ind)(NMe2)2Me, 6, respectively. Chloride metathesis reactions of Ti(Ind)(NMe2)2Cl with Me3SiCH2MgCl, LiCCPh and LiCCSiMe3 gave Ti(Ind)(NMe2)2(CH2SiMe3), 7, Ti(Ind)(NMe2)2(CCPh), 8 and Ti(Ind)(NMe2)2(CCSiMe3), 9. The solid-state molecular structure of 2 was determined. 1H and 13C NMR data and DFT calculations (full geometry optimisations) showed that the indenyl ring remains approximately planar and exhibits an η5 co-ordination mode in all the complexes. The amido groups have a preference for binding in the way that favours π bonding to the titanium. Even in the trisamido complex the indenyl remains η5, π bonding to the ring being preferred to that from the amides.