- PREPARATION AND CHEMICAL BEHAVIOUR OF HALOCYCLOPENTADIENYL-ZIRCONIUM(III) AND -HAFNIUM(III)
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Reduction of (η5-C5H5)2MCl2 (M=Zr, Hf) with one equivalent of Na/Hg gives 5-C5H5)2M(μ-Cl)>2.The zirconium(III) complex is also obtained from reactions between LiCp and 2>2 (L2=2P-n-Bu3, dppe) or solutions of ZrCl4 previously reduced with Na/Hg.These zirconium(III) and hafnium(III) complexes are oxidized by AgBF4 or TlBF4 to the cationic 5-C5H5)2M(μ-Cl)>22+ complexes, which react with monodentate ligands to give 5-C5H5)MClL>+ (L=OPPh3, NHPh2) and with bidentate ligands to give dinuclear cationic derivatives5-C5H5)2MCl>2(μ-L-L)>2+ (L-L-dppe, 2,2'-bipyridine).Similar complexes can also be obtained from (η5-C5H5)2MCl2 by halide abstraction with a silver salt.Oxidation of zirconium(III) and hafnium(III) derivatives with halogens gives (η5-C5H5)MClX (X=Cl, Br) and 5-C5H5)2ZrCl(OPPh3)>I3.Conductivity, magnetic susceptibility and IR and NMR data are discussed.
- Cuenca, T.,Royo, P.
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- Structural diversity in tris(cyclopentadienyl) complexes of the Group 4 metals: Synthesis of Cp and MeCp complexes of Zr and Hf, and crystallographic characterization of (MeCp)3HfCl and (MeCp)4Zr (MeCp = C5H4CH3)
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Previous theoretical studies have predicted structural differences between the tris(cyclopentadienyl) zirconium and hafnium complexes Cp3MX (Cp = C5H5;M = Zr, Hf). Cp3ZrCl can be isolated via the stoichiometric reaction of Cp2ZrCl2 and NaCp, but forming the analogous Hf complex is complicated by ligand redistribution. Partial crystallographic analysis of these two complexes indicates likely structural differences wherein the Zr complex has three η5 Cp ligands ("3-5" structure) while the Hf complex has two η5 Cp ligands and one η1 Cp ligand ("2-5,1-1" structure). The use of C5H4CH 3 (MeCp) simplifies both the syntheses and the procurement of suitable crystals. The preparation of a number of MeCp complexes of Zr and Hf is reported along with crystallographic characterization of (MeCp) 3HfCl, which has a 2-5,1-1 structure and (MeCp)4Zr, which has a 3-5,1-1 structure.
- Palmer, Erick J.,Strittmatter, Richard J.,Thornley, Keith T.,Gallucci, Judith C.,Bursten, Bruce E.
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- THERMAL DECOMPOSITION OF BIS(CYCLOPENTADIENYL)HAFNIUM COMPOUNDS AND THEIR DEUTERATED ANALOGUES
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Thermal decomposition ranges of Cp2HfR2 (R=Me, Ph) have been found by the DTA method.The thermal stability of hafnium derivatives greatly exceeds the stability of analogous titanium and zirconium compounds.Decomposition of Cp2HfR2 occurs by abstraction of ?-bonded groups which convert into RH.Hydrogen donors for the RH formation are both ?-cyclopentadienyl and ?-bonded groups.The initial ?-Cp2Hf structure rearranges to form the (η5-Cp)-(η5,η1-C5H4)Hf fragment.These react with HCl to produce Cp2HfCl2.It has been established that hydrogen exchange between cyclopentadienyl rings and methyl groups occurs during the thermal decomposition of Cp2HfMe2.As a result of the exchange process on thermal decomposition of Cp2HfMe2-d6, deuterium insertion into the cyclopentadienyl ring has been shown.The participation of solvent during the decomposition process of the hafnium derivatives has been studied.
- Razuvaev, G. A.,Mar'In, V. P.,Drushkov, O. N.,Vyshinskaya, L. I.
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- Photoresist based on metallocene compound and preparation method and application thereof
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The invention belongs to the technical field of photoresist, and particularly relates to a photoresist based on a metallocene compound as well as a preparation method and application of the photoresist. The metallocene compound disclosed by the invention adopts metal as a central core structure, so that the metallocene compound has a relatively high melting point and glass-transition temperature, can meet the requirements of a photoetching technology, and is stable in structure, and a film structure is not changed during high-temperature baking. In addition, the photoresist composition provided by the invention can be used in modern photoetching processes such as 248nm photoetching, 193nm photoetching, extreme ultraviolet (EUV) photoetching, nanoimprint lithography (NIL), electron beam lithography (EBL) and the like, and is particularly suitable for being used in an extreme ultraviolet (EUV) photoetching process.
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Paragraph 0101; 0109; 0110-0111
(2021/05/26)
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- Palladium-Catalyzed Reductive Coupling Reaction of Terminal Alkynes with Aryl Iodides Utilizing Hafnocene Difluoride as a Hafnium Hydride Precursor Leading to trans-Alkenes
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Herein, we describe a reductive cross-coupling of alkynes and aryl iodides by using a novel catalytic system composed of a catalytic amount of palladium dichloride and a promoter precursor, hafnocene difluoride (Cp2HfF2, Cp=cyclopentadienyl anion), in the presence of a mild reducing reagent, a hydrosilane, leading to a one-pot preparation of trans-alkenes. In this process, a series of coupling reactions efficiently proceeds through the following three steps: (i) an initial formation of hafnocene hydride from hafnocene difluoride and the hydrosilane, (ii) a subsequent hydrohafnation toward alkynes, and (iii) a final transmetalation of the alkenyl hafnium species to a palladium complex. This reductive coupling could be chemoselectively applied to the preparation of trans-alkenes with various functional groups, such as an alkyl group, a halogen, an ester, a nitro group, a heterocycle, a boronic ester, and an internal alkyne.
- Takahashi, Keita,Ogiwara, Yohei,Sakai, Norio
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supporting information
p. 809 - 814
(2018/03/13)
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- Group 4 metallocene complexes with pendant nitrile groups
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The preparation of a new functionalized cyclopentadienyl ligand bearing a nitrile pendant substituent, (C5H4CMe2CH 2CN)- is reported. The corresponding lithium salt of this ligand (1) was prepared by the reaction of in situ lithiated acetonitrile with 6,6-dimethylfulvene. The ligand was subsequently utilized for the synthesis of group 4 metal complexes [(η5-C5H4CMe 2CH2CN)2MCl2] (M = Ti, 2; M = Zr, 3; M = Hf, 4), [(η5-C5H5) (η5-C5H4CMe2CH 2CN)MCl2] (M = Ti, 7; M = Zr, 8), and [(η5- C5Me5) (η5 C5H 4CMe2CH2CN)2ZrCl2] (9). Alternative route to 2 comprised the preparation of half-sandwich complex [(η5-C5H4CMe2CH 2CN)TiCl3] (6). The prepared compounds were characterized by common spectroscopic methods and the solid state structures of complexes 2, 3, 4, 7, and 9 were determined by the single-crystal X-ray diffraction analysis. In addition, compound 7 was converted to the corresponding dimethyl derivative [(η5-C5H5) (η5-C 5H4CMe2CH2CN)TiMe2] (10) and also treated with the chloride anion abstractor Li[B(C6F 5)4] to generate the cationic complex with the coordinated nitrile group, as suggested by the NMR spectroscopy. A formation of yet another cationic complex was observed upon treating compound 10 with (Ph 3C)[B(C6F5)4].
- Pinkas, Ji?í,Gyepes, Róbert,Kubi?ta, Ji?í,Horá?ek, Michal,Lama?, Martin
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p. 2364 - 2372
(2011/06/26)
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- Hafnium-phosphinimide complexes
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A series of phosphinimide complexes of Hf are prepared and characterized. Reaction of the phosphinimine t-Bu3PNH with Hf(NEt2) 4 gave (t-Bu3PN)Hf(NEt2)3 (1) but this species was not readily
- Alhomaidan, Osamah,Welch, Gregory C.,Bai, Guangcai,Stephan, Douglas W.
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p. 1163 - 1172
(2009/12/01)
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- Cyclopentadienylmetal trichloride formation versus metallocene dichloride formation in the reactions of silylated cyclopentadienes with zirconium and hafnium chlorides. Crystal structure of (1,3-bis- (trimethylsilyl)cyclopentadienyl)titanium trichloride
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The reaction of zirconium and hafnium tetrachlorides with tris(trimethylsilyl)cyclopentadiene affords the monocyclopentadienyl complexes (1,3-bis(trimethylsily)cyclopentadienyl)zirconium trichloride (1, 73%) and (1,3-bis(trimethylsilyl)cyclopentadienyl)hafnium trichloride (2, 76%) in good isolated yields. The reaction of 1 with (1,3-bis(trimethylsilyl)cyclopentadienyl)lithium affords 1,1′,3,3′-tetrakis(trimethylsilyl)zirconocene dichloride (74%). In contrast to the preparations of 1 and 2, reaction of bis(trimethylsilyl)cyclopentadiene with zirconium and hafnium tetrachlorides affords 1,1′-bis- (trimethylsilyl)zirconocene dichloride (5, 73%) and 1,1′-bis(trimethylsilyl)hafnocene dichloride (6, 76%). The reaction of (trimethylsilyl)cyclopentadiene with zirconium and hafnium tetrachlorides affords zirconocene dichloride (7, 91%) and hafnocene dichloride (8, 90%). The intermediacy of monocyclopentadienyl species in the preparation of the metallocene dichlorides is supported by the reaction of cyclopentadienylzirconium trichloride with (trimethylsilyl)cyclopentadiene to afford 7 (85%). Reaction of zirconium tetrachloride with 1 equiv of (trimethylsilyl)cyclopentadiene at 0 °C for 0.5 h affords 7 and cyclopentadienylzirconium trichloride in a (69 ± 2):(31 ± 2) ratio. The silyl group regiochemistry in 1 and 2 was established through an X-ray crystal structure determination of the titanium analogue (1,3-bis(trimethylsilyl)cyclopentadienyl)titanium trichloride (3). Complex 3 crystallizes in the orthorhombic space group Pbnm with a = 7.459 (3) angstrom, b = 11.799 (3) angstrom, c = 20.535 (3) angstrom, V = 1807.1 (9) angstrom3, and Z = 4.
- Winter,Zhou,Dobbs,Heeg
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p. 210 - 214
(2008/10/08)
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- Some metallabicyclo-octadienes and -nonadienes of dicyclopentadienyltitanium, -zirconium and -hafnium
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Titanocene, zirconocene, and hafnocene dichlorides were reduced in the presence of terminally disubstituted 1,6-heptadiyne or 1,7-octadiyne to produce dicyclopentadienylmetallabicyclooctadienes and -nonadienes.The compounds were characterized by elemental
- Yousaf, Shahid M.,Farona, Michael F.,Shively, Raymond J.,Youngs, Wiley J.
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p. 281 - 290
(2007/10/02)
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- Transition Metal-Phosphide Chemistry: Synthesis of (M(η-C5H5)2(PR2)2) (M=Zr, R=Ph; M=Hf, R=Ph or cyclo-C6H11) and ((M(η-C5H5)2(PR2))2) (M=Ti, R=Ph or Me; M=Zr or Hf, R=Me), and their Reactions with Protic and Halogen-containing Species
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Reactions of the metallocene dichlorides (M(cp)2Cl2) (M=Ti, Zr, or Hf; cp=η-C5H5) with stoicheiometric amounts of LiPR2 (R= Me, Ph, or cyclo-C6H11) yield either the direct exchange products (M(IV)(cp)2(PR2)2) (M=Zr, R=Ph; M=Hf, R=Ph or C6H11) or the reduced species ((M(III)(cp)2 (PR2))2) M=Ti, R=Me or Ph; M=Zr or Hf, R=Me).Spectral (i.r. and (1)H n.m.r.) characterisation of these compounds is presented and discussed with suggestions of possible structures.Treatment of (Zr(cp)2(PPh2)2) with PPh3Cl affords the 'mixed' chloro-phosphido-compound (Zr(cp)2Cl(PPh2)).Reactions of both the M(IV) and M(III) species with halogen-containing and protic reagents have been investigated.Each series reacts with smooth cleavage of the M-P bond(s), but whereas the compounds (M(cp)2(PR2)2) (M=Ti, Zr, or Hf) show simple metathetical exchange, ((M(cp)2(PR))2)usually (and in the case of M=Zr or Hf exclusively) also incorporate metal oxidation M(III) M(IV) into their reactions.
- Wade, Steven R.,Wallbridge, Malcolm G. H.,Willey, Gerald R.
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p. 2555 - 2560
(2007/10/02)
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- Metallocene Derivatives of Early Transition Metals. Part 4. Chemistry of the Complexes and the X-Ray Structures of (M' = C or Si)
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The metallocene(IV) halogeno-alkyls have been prepared either by interaction of the appropriate Grignard reagent and or from and Mg(CH2SnMe3)X (Cl-X exchange).Metallocene(IV) dialkyls (type (iv) R = CH2SnMe3 = R', M = Ti, Zr, of Hf; type (v) R = CH2SnMe3, R' = CH2SiMe3, M = Ti, Zr, or Hf; type (vi) R = CH2CMe3 = R', M = Ti or Zr; type (vii) R = CH2SnMe3; R' = CH2CMe3, CH2GeMe3, or Me; M = Ti; type (viii) R = CH2SiMe3, R' = CH2GeMe3, M = Ti; type (ix) R = CH(SiMe3)2; R' = Me, Et, Prn, CH2SiMe3, or Ph; M = Zr> have been synthesised by reaction of (a) with 2Mg(CH2SnMe3)X (X = Cl or Br) or (b) with LiR'.Also obtained are and H)2>, the latter from and Li or and successively Lit)3> and Li.The reaction of an equimolar portion of HCl in OEt2 and gives predominantly the products of CH2-SnMe3, rather than Ti-CH2, scission.By contrast, the dialkyls , containing one or two CH2SnMe3 ligands, give largely RH or R'H and ; the relative ability of R as a leaving group decreases in the sequence CH2SnMe3 > CH2CMe3 > CH2SiMe3 >= CH2GeMe3 > CH3, the distinctions being more marked for Ti than Zr of Hf.The dialkyds are generally stable when heated at 80 deg C in PhMe, except for the titanium complexes; (M' = Si or Ge) gives M'Me4 as the sole volatile product, with ti 110 (M' = Si) or 140 min (M' = Sn).Treatment of in C6H6 with CO under ambient conditions affords the appropriate ε2-acyl 2-COR)X> ; the formation of type (xi), rather than the isomer resulting from CO insertion into the less hindered Zr-Me bond, is noteworthy.A single-crystal X-ray diffraction study has been carried out on , with a = 9.142(4), b = 9.142(4). c = 23.326(9) Angstroem, β = 90 deg, and Z = 4.Crystals of (42) are monoclinic, space group P21/n, a = 13.745(6), b = 7.048(3), c = 22.057(9) Angstroem, β = 95.65(4) deg, and Z = 4.For complex (28), 487 reflections have been considered and the data refined to R = 0.029, R' = 0.032; for complex (42), 2688 independent reflections led to R = 0.029, R' = 0.033.The slightly larger steric requirement of the neopentyl ligand compared with -CH2SiMe3 manifests itself in a larger Zr-cyclopentadienyl approach but the Zr-CH2 bond length is indistinguishable, 2.51(2) Angstroem for (28) and 2.52(2) Angstroem for (42).
- Jeffery, John,Lappert, Michael F.,Luong-Thi, N. Tuyet,Webb, Maurice,Atwood, Jerry L.,Hunter, William E.
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p. 1593 - 1605
(2007/10/02)
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