Synthetic and structural studies on some organic compounds of zirconium (original) (raw)
Related papers
Journal of Organometallic Chemistry, 2006
The dialkyl complexes, ½ZrfRðHÞCðg 5 -C 5 Me 4 Þðg 5 -C 5 H 4 ÞgR 0 2 (R = Pr i , R 0 = Me (2a), CH 2 Ph (3a); R = Bu n , R 0 = Me (2b), CH 2 Ph (3b); R = Bu t , R 0 = Me (2c), CH 2 Ph (3c); R = Ph, R 0 = Me (2d), CH 2 Ph (3d)), have been synthesized by the reaction of the ansa-metallocene dichloride complex, [Zr{R(H)C(g 5 -C 5 Me 4 )(g 5 -C 5 H 4 )}Cl 2 ] (R = Pr i (1a), Bu n (1b), Bu t (1c), Ph (1d)), and two molar equivalents of the alkyl Gringard reagent. The insertion reaction of the isocyanide reagent, CNC 6 H 3 Me 2 -2,6, into the zirconium-carbon r-bond of 2 gave the corresponding g 2 -iminoacyl derivatives, [Zr{R(H)C(g 5 -C 5 Me 4 )(g 5 -C 5 H 4 )}{g 2 -MeC@NC 6 H 3 Me 2 -2,6}Me] (R = Pr i (4a), Bu n (4b), Bu t (4c), Ph (4d)). The molecular structures of 1b, 1c and 3b have been determined by single-crystal X-ray diffraction studies.
Journal of …, 2006
The dialkyl complexes, ½ZrfRðHÞCðg 5 -C 5 Me 4 Þðg 5 -C 5 H 4 ÞgR 0 2 (R = Pr i , R 0 = Me (2a), CH 2 Ph (3a); R = Bu n , R 0 = Me (2b), CH 2 Ph (3b); R = Bu t , R 0 = Me (2c), CH 2 Ph (3c); R = Ph, R 0 = Me (2d), CH 2 Ph (3d)), have been synthesized by the reaction of the ansa-metallocene dichloride complex, [Zr{R(H)C(g 5 -C 5 Me 4 )(g 5 -C 5 H 4 )}Cl 2 ] (R = Pr i (1a), Bu n (1b), Bu t (1c), Ph (1d)), and two molar equivalents of the alkyl Gringard reagent. The insertion reaction of the isocyanide reagent, CNC 6 H 3 Me 2 -2,6, into the zirconium-carbon r-bond of 2 gave the corresponding g 2 -iminoacyl derivatives, [Zr{R(H)C(g 5 -C 5 Me 4 )(g 5 -C 5 H 4 )}{g 2 -MeC@NC 6 H 3 Me 2 -2,6}Me] (R = Pr i (4a), Bu n (4b), Bu t (4c), Ph (4d)). The molecular structures of 1b, 1c and 3b have been determined by single-crystal X-ray diffraction studies.
Organometallics, 1997
Alkylation of [Zr(CpSi 2 Cp)Cl 2 ] (CpSi 2 Cp) (η 5-C 5 H 3) 2 [Si(CH 3) 2 ] 2 with 1 equiv of RMgCl in THF at 10°C gave the monoalkylated complexes [Zr(CpSi 2 Cp)ClR] (R) Et, n-Pr, i-Pr) in 80% yield, the isopropyl complex isomerizing to the n-propyl derivative above 10°C. Addition of a second equivalent or an excess amount of the akylating agent resulted in the formation of the dialkyl compounds [Zr(CpSi 2 Cp)R 2 ] (R) Et, n-Pr). Hydrolysis of [Zr(CpSi 2 Cp)ClR] led to the µ-oxo dinuclear complex [{Zr(CpSi 2 Cp)Cl} 2 (µ-O)]. Thermal decomposition of THF solutions of [Zr(CpSi 2 Cp)ClR] takes place with the evolution of an equimolar amount of alkane and alkene and the formation of [Zr(CpSi 2 Cp)Cl 2 ] and an unidentified residue. Formation of [Zr(CpSi 2 Cp)Et 2 ] is always accompanied by decomposition with the evolution of ethane to give [{Zr(CpSi 2 Cp)Et} 2 (µ-CH 2 dCH 2)] in 70% yield. A similar behavior was observed for [Zr(CpSi 2 Cp)(n-Pr) 2 ]. All of the compounds were characterized by elemental analysis and NMR spectroscopy, and the molecular structures of [Zr(CpSi 2 Cp)ClEt] and [{Zr(CpSi 2 Cp)-Et} 2 (µ-CH 2 dCH 2)] were studied by X-ray diffraction methods. Density functional calculations on the model compound [{ZrCp 2 Me} 2 (µ-CH 2 dCH 2)] satisfactorily reproduce d CC) 1.482, d1 Zr-C) 2.327 Å, and d2 Zr-C) 2.506 Å, the geometry found experimentally.
Journal of …, 2008
The ansa-bis(cyclopentadiene) compounds, Me 2 Si(C 5 HPh 4 )(C 5 H 4 R) (R = H (2); Bu t (3)), have been prepared by the reaction of C 5 HPh 4 (SiMe 2 Cl) (1) with Na(C 5 H 5 ) or Li(C 5 H 4 Bu t ), respectively, and transformed to the di-lithium derivatives, Li 2 {Me 2 -Si(C 5 Ph 4 )(C 5 H 3 R)} (R = H (4); Bu t (5)), by the action of n-butyllithium. The ansa-zirconocene complexes, [Zr{Me 2 Si(g 5 -C 5 Ph 4 )(g 5 -C 5 H 3 R)}Cl 2 ] (R = H (6); Bu t (7)), were synthesized from the reaction of ZrCl 4 with 4 or 5, respectively. Compounds 6 and 7 have been tested in the polymerization of ethylene and compared with their methyl-substituted analogues, [Zr{Me 2 Si(g 5 -C 5 Me 4 )(g 5 -C 5 H 3 R)}Cl 2 ] (R = H (8); Bu t (9)). Whilst 8 and 9 are catalytically active, the tetraphenyl-substituted complexes 6 and 7 proved to be inactive in the polymerization of ethylene. This phenomenon has been explained by DFT calculations based on the reaction intermediates in the polymerization processes involving 6 and 7, which showed that the extraction of a methyl group from the zirconocene complex to form the cationic active specie is endothermic and therefore unfavourable.
Zirconium Reagents in Organic Synthesis
Organic Synthesis Today and Tomorrow, 1981
Abstract Carbon-carbon bond-forming procedures are described which involve organozirconium complexes in tandem with other metallic species. Mechanistic considerations for these reactions are described.
Polyhedron, 1990
Reaction of all asymmetric phenols 2-methyl,6-tert-butylphenol (HOAr-2Me,6Bu') and 2,4-dimethyl,6-(a-methylcyclohexyl)phenol (HOAr-2,4Me,,6cyMe) with Cp,Zr(CH,Ph), at 120°C in toluene leads to the slow formation of the mono-substituted derivatives CpzZr(OAr-2Me,6Bu')(CH,Ph) (1) and Cp,Zr(OAr-2,4Mez,6cyMe)(CH,Ph) (2) along with one equivalent of toluene. A single crystal X-ray diffraction analysis of 2 confirmed the stoichiometry and shows the carbon and oxygen atoms of the benzyl and aryloxide ligands occupying positions about the zirconium atom typical of Cp,Zr(X)(Y) type compounds. The large Zr-0-Ar angle of 165.3(5)' results in the aryloxide occupying a "wedge-like" space within the coordination sphere. This wedge is oriented within the plane which bisects the metallocene unit, i.e. almost coplanar with the ZrCO plane, and is oriented so that the bulky a-methylcyclohexyl group lies next to the benzyl ligand. The reaction of 1 with Bu'NC also takes place very slowly leading to the q2-iminoacyl compound Cp,Zr(OAr-2Me,6Bu')(q2-Bu'NCCH,Ph) (3). Despite the steric demands of the bulky aryloxide ligand, the spectroscopic and structural data on 3 show the iminoacyl to be q2bonded to zirconium, Zr-N = 2.244(4) A, Zr-C = 2.208(5) A. In the solid state the 1%electron compound 3 has the q2-iminoacyl group lying along the plane bisecting the metallocene unit.
Inorganic Chemistry, 2002
Treatment of 1,2-C 6 H 4 (SiH 3)(SiH 3) (1) with [Pt(depe)(PEt 3) 2 ] (depe = Et 2 PCH 2 CH 2 PEt 2) in the ratio of 1:1 yields the complex [Pt II {1,2-C 6 H 4 (SiH 2)(SiH 2)}(depe)] (2), which has unique reactivity towards sterically unhindered alcohol to form an unusual tetra-alkoxy substituted silyl platinum(II) compound (3). Only 2 examples of bis(silyl)platinum(II) complexes prepared from this chelating hydrosilane ligand have been registered in the Cambridge Structural Database. The structure of complex (3) was unambiguously determined by multinuclear NMR spectroscopic studies and single crystal X-ray analysis.