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1.
Reactions of Group 4 Metallocenes with Monosubstituted Acetonitriles: Keteniminate Formation versus CC Coupling
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Lisanne Becker Dr. Martin Haehnel Dr. Anke Spannenberg Dr. Perdita Arndt Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3242-3248
The reactions of the Group 4 metallocene dichlorides [Cp′2MCl2] ( 1 a : M=Ti, Cp′=Cp*=η5‐pentamethylcyclopentadienyl, 1 b : M=Zr, Cp′=Cp=η5‐cyclopentadienyl) with lithiated MesCH2?C?N gave [Cp*2TiCl(N=C=C(HMes))] ( 3 ; Mes=mesityl) in the case of 1 a . For compound 1 b , a nitrile–nitrile coupling resulted in a five‐membered bridge in 4 . The reaction of the metallocene alkyne complex [Cp*2Zr(η2‐Me3SiC2SiMe3)] ( 2 ) with PhCH2?C?N led in the first step to the unstable product [Cp*2Zr(η2‐Me3SiC2SiMe3)(NC?CH2Ph)] ( 5 ). After the elimination of the alkyne, a mixture of products was formed. By variation of the solvent and the reaction temperature, three compounds were isolated: a diazadiene complex 6 , a bis(keteniminate) complex 7 , and 8 with a keteniminate ligand and a five‐membered metallacycle. Subsequent variation of the Cp ligand and the metal center by using [Cp2Zr] and [Cp*2Ti] with Me3SiC2SiMe3 in the reactions with PhCH2?C?N gave complex mixtures. 相似文献
2.
Dipl.‐Chem. Lisanne Becker Dr. Perdita Arndt Dr. Anke Spannenberg Prof. Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(39):12595-12600
The reactions of the Group 4 metallocene alkyne complexes rac‐(ebthi)M(η2‐Me3SiC2SiMe3) ( 1 a : M=Ti, 1 b : M=Zr; rac‐(ebthi)=rac‐1,2‐ethylene‐1,1′‐bis(η5‐tetrahydroindenyl)) with Ph?C?N were investigated. For 1 a , an unusual nitrile–nitrile coupling to 1‐titana‐2,5‐diazacyclopenta‐2,4‐diene ( 2 ) at ambient temperature was observed. At higher temperature, the C?C coupling of two nitriles resulted in the formation of a dinuclear complex with a four‐membered diimine bridge ( 3 ). The reaction of 1 b with Ph?C?N afforded dinuclear compound 4 and 2,4,6‐triphenyltriazine. Additionally, the reactivity of 1 b towards other nitriles was investigated. 相似文献
3.
Four‐Membered Heterometallacyclic d0 and d1 Complexes of Group 4 Metallocenes with Amidato Ligands
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Dr. Martin Haehnel Jacqueline B. Priebe Jacky C.‐H. Yim Dr. Anke Spannenberg Prof. Dr. Angelika Brückner Prof. Dr. Laurel L. Schafer Prof. Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(25):7752-7758
A study of the coordination chemistry of different amidato ligands [(R)N?C(Ph)O] (R=Ph, 2,6‐diisopropylphenyl (Dipp)) at Group 4 metallocenes is presented. The heterometallacyclic complexes [Cp2M(Cl){κ2‐N,O‐(R)N?C(Ph)O}] M=Zr, R=Dipp ( 1 a ), Ph ( 1 b ); M=Hf, R=Ph ( 2 )) were synthesized by reaction of [Cp2MCl2] with the corresponding deprotonated amides. Complex 1 a was also prepared by direct deprotonation of the amide with Schwartz reagent [Cp2Zr(H)Cl]. Salt metathesis reaction of [Cp2Zr(H)Cl] with deprotonated amide [(Dipp)N?C(Ph)O] gave the zirconocene hydrido complex [Cp2M(H){κ2‐N,O‐(Dipp)N?C(Ph)O}] ( 3 ). Reaction of 1 a with Mg did not result in the desired Zr(III) complex but in formation of Mg complex [(py)3Mg(Cl) {κ2‐N,O‐(Dipp)N?C(Ph)O}] ( 4 ; py=pyridine). The paramagnetic complexes [Cp′2Ti{κ2‐N,O‐(R)N?C(Ph)O}] (Cp′=Cp, R=Ph ( 7 a ); Cp′=Cp, R=Dipp ( 7 b ); Cp′=Cp*, R=Ph ( 8 )) were prepared by the reaction of the known titanocene alkyne complexes [Cp2′Ti(η2‐Me3SiC2SiMe3)] (Cp′=Cp ( 5 ), Cp′=Cp* ( 6 )) with the corresponding amides. Complexes 1 a , 2 , 3 , 4 , 7 a , 7 b , and 8 were characterized by X‐ray crystallography. The structure and bonding of complexes 7 a and 8 were also characterized by EPR spectroscopy. 相似文献
4.
Lisanne Becker Frank Strehler Marcus Korb Dr. Perdita Arndt Dr. Anke Spannenberg Dr. Wolfgang Baumann Prof. Dr. Heinrich Lang Prof. Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):3061-3068
The reactions of the Group 4 metallocene alkyne complexes, [Cp*2M(η2‐Me3SiC2SiMe3)] ( 1 a : M=Ti, 1 b : M=Zr, Cp*=η5‐pentamethylcyclopentadienyl), with the ferrocenyl nitriles, Fc?C?N and Fc?C?C?C?N (Fc=Fe(η5‐C5H5)(η5‐C5H4)), is described. In case of Fc?C?N an unusual nitrile–nitrile C?C homocoupling was observed and 1‐metalla‐2,5‐diaza‐cyclopenta‐2,4‐dienes ( 3 a , b ) were obtained. As the first step of the reaction with 1 b , the nitrile was coordinated to give [Cp*2Zr(η2‐Me3SiC2SiMe3)(N?C‐Fc)] ( 2 b ). The reactions with the 3‐ferrocenyl‐2‐propyne‐nitrile Fc?C?C?C?N lead to an alkyne–nitrile C?C coupling of two substrates and the formation of 1‐metalla‐2‐aza‐cyclopenta‐2,4‐dienes ( 4 a , b ). For M=Zr, the compound is stabilized by dimerization as evidenced by single‐crystal X‐ray structure analysis. The electrochemical behavior of 3 a , b and 4 a , b was investigated, showing decomposition after oxidation, leading to different redox‐active products. 相似文献
5.
Highly Strained Heterometallacycles of Group 4 Metallocenes with Bis(diphenylphosphino)amide Ligands
Martin Haehnel Sven Hansen Dr. Anke Spannenberg Dr. Perdita Arndt Dr. Torsten Beweries Prof. Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(34):10546-10553
A study regarding coordination chemistry of the bis(diphenylphosphino)amide ligand Ph2P‐N‐PPh2 at Group 4 metallocenes is presented herein. Coordination of N,N‐bis(diphenylphosphino)amine ( 1 ) to [(Cp2TiCl)2] (Cp=η5‐cyclopentadienyl) generated [Cp2Ti(Cl)P(Ph2)N(H)PPh2] ( 2 ). The heterometallacyclic complex [Cp2Ti(κ2‐P,P‐Ph2P‐N‐PPh2)] ( 3 Ti ) can be prepared by reaction of 2 with n‐butyllithium as well as from the reaction of the known titanocene–alkyne complex [Cp2Ti(η2‐Me3SiC2SiMe3)] with the amine 1 . Reactions of the lithium amide [(thf)3Li{N(PPh2)2}] with [Cp2MCl2] (M=Zr, Hf) yielded the corresponding zirconocene and hafnocene complexes [Cp2M(Cl){κ2‐N,P‐N(PPh2)2}] ( 4 Zr and 4 Hf ). Reduction of 4 Zr with magnesium gave the highly strained heterometallacycle [Cp2Zr(κ2‐P,P‐Ph2P‐N‐PPh2)] ( 3 Zr ). Complexes 2 , 3 Ti , 4 Hf , and 3 Zr were characterized by X‐ray crystallography. The structures and bondings of all complexes were investigated by DFT calculations. 相似文献
6.
Prof. Uwe Rosenthal 《ChemistryOpen》2021,10(12):1234-1243
Recently published reactions of group 4 metallocene bis(trimethylsilyl)acetylene (btmsa) complexes from the last two years are reviewed. Complexes like Cp’2Ti(η2-Me3SiC2SiMe3) and Cp2Zr(py)(η2-Me3SiC2SiMe3) with Cp’ as Cp (cyclopentadienyl) and Cp* (pentamethylcyclopentadienyl) have been considered (py=pyridine). These complexes can liberate a reactive low-valent titanium or zirconium center by dissociation of the ligands and act as ‘‘masked’’ MII complexes (M=Ti, Zr). They represent excellent sources for the clean generation of the reactive coordinatively and electronically unsaturated complex fragments [Cp’2M]. This is the reason why they were used for many synthetic and catalytic reactions during the last years. As an update to several review articles on this topic, this contribution provides an update with recent examples of preparative organometallic and organic chemistry of these complexes, acting as reagents for a wide range of coordinating and coupling reactions. In addition, applications and investigations concerning reaction products derived from this chemistry are mentioned, too. 相似文献
7.
Dr. Katharina Kaleta Frank Strehler Dr. Alexander Hildebrandt Dr. Torsten Beweries Dr. Perdita Arndt Dr. Tobias Rüffer Dr. Anke Spannenberg Prof. Dr. Heinrich Lang Prof. Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(40):12672-12680
The reaction of different metallocene fragments [Cp2M] (Cp=η5‐cyclopentadienyl, M=Ti, Zr) with diferrocenylacetylene and 1,4‐diferrocenylbuta‐1,3‐diyne is described. The titanocene complexes form the highly strained three‐ and five‐membered ring systems [Cp2Ti(η2‐FcC2Fc)] ( 1 ) and [Cp2Ti(η4‐FcC4Fc)] ( 2 ) (Fc=[Fe(η5‐C5H4)(η5‐C5H5)]) by addition of the appropriate alkyne or diyne to Cp2Ti. Zirconocene precursors react with diferrocenyl‐ and ferrocenylphenylacetylene under C? C bond coupling to yield the metallacyclopentadienes [Cp2Zr(C4Fc4)] ( 3 ) and [Cp2Zr(C4Fc2Ph2)] ( 5 ), respectively. The exchange of the zirconocene unit in 3 by hydrogen atoms opens the route to the super‐crowded ferrocenyl‐substituted compound tetraferrocenylbutadiene ( 4 ). On the other hand, the reaction of 1,4‐diferrocenylbuta‐1,3‐diyne with zirconocene complexes afforded a cleavage of the central C? C bond, and thus, dinuclear [{Cp2Zr(μ‐η1:η2‐C?CFc)}2] ( 6 ) that consists of two zirconocene acetylide groups was formed. Most of the complexes were characterized by single‐crystal X‐ray crystallography, showing attractive multinuclear molecules. The redox properties of 3 , 5 , and 6 were studied by cyclic voltammetry. Upon oxidation to 3 n+, 5 n+, and 6 n+ (n=1–3), decomposition occured with in situ formation of new species. The follow‐up products from 3 and 5 possess two or four reversible redox events pointing to butadiene‐based molecules. However, the dinuclear complex 6 afforded ethynylferrocene under the measurement conditions. 相似文献
8.
D. Thomas N. Peulecke V. V. Burlakov B. Heller W. Baumann A. Spannenberg R. Kempe U. Rosenthal R. Beckhaus 《无机化学与普通化学杂志》1998,624(5):919-924
Desactivation of Catalysts in the Polymerization of Acetylene by Bis(trimethylsilyl)acetylene Complexes of Titanocene or Zirconocene Unexpected inactive byproducts were observed in the catalytic polymerization of acetylene using metallocene alkyne complexes Cp2M(L)(η2-Me3SiC2SiMe3), 1 : M = Ti, without L; 2 : M = Zr, L = thf. The reaction of 1 was investigated in detail by NMR to give quantitatively at –20 °C the titanacyclopentadiene Cp2Ti–CH=CH–C(SiMe3)=C(SiMe3) ( 3 ). Around 0 °C 3 starts to rearrange to yield the dihydroindenyl complex 4 via coupling of one Cp-ligand with the titanacyclopentadiene. In the reaction of 2 under analogous conditions a zirconacyclopentadiene Cp2Zr–CH=CH–C(SiMe3)=C(SiMe3) ( 5 ) and the dimeric complex [Cp2Zr(C(SiMe3)=CH(SiMe3)]2[μ-σ(1,2)-C≡C] ( 6 ) were observed. Whereas 5 decomposes to a mixture of unidentified paramagnetic species, 6 was isolated and investigated by NMR spectroscopy and X-ray analysis. In the reaction of rac-(ebthi)Zr(η2-Me3SiC2SiMe3) (ebthi = ethylenbistetrahydroindenyl) with 2-ethynyl-pyridine the complex rac-(ebthi)ZrC(SiMe3)=CH(SiMe3)](σ-C≡CPy) 7 was obtained, which was investigated by an X-ray analysis. 相似文献
9.
Eric Mädl Dr. Mikhail V. Butovskii Dr. Gábor Balázs Dr. Eugenia V. Peresypkina Dr. Alexander V. Virovets Michael Seidl Prof. Dr. Manfred Scheer 《Angewandte Chemie (International ed. in English)》2014,53(29):7643-7646
Unprecedented functionalized products with an η4‐P5 ring are obtained by the reaction of [Cp*Fe(η5‐P5)] ( 1 ; Cp*=η5‐C5Me5) with different nucleophiles. With LiCH2SiMe3 and LiNMe2, the monoanionic products [Cp*Fe(η4‐P5CH2SiMe3)]? and [Cp*Fe(η4‐P5NMe2)]?, respectively, are formed. The reaction of 1 with NaNH2 leads to the formation of the trianionic compound [{Cp*Fe(η4‐P5)}2N]3?, whereas the reaction with LiPH2 yields [Cp*Fe(η4‐P5PH2)]? as the main product, with {[Cp*Fe(η4‐P5)]2PH}2? as a byproduct. The calculated energy profile of the reactions provides a rationale for the formation of the different products. 相似文献
10.
Monty Kessler Dr. Sven Hansen Christian Godemann Dr. Anke Spannenberg Dr. Torsten Beweries 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(20):6350-6357
The synthesis of a series of ansa‐titanocene dichlorides [Cp′2TiCl2] (Cp′=bridged η5‐tetramethylcyclopentadienyl) and the corresponding titanocene bis(trimethylsilyl)acetylene complexes [Cp′2Ti(η2‐Me3SiC2SiMe3)] is described. The ethanediyl‐bridged complexes [C2H4(C5Me4)2TiCl2] ( 2 ‐Cl2) and [C2H4(C5Me4)2Ti(η2‐Me3SiC2SiMe3)] ( 2‐ btmsa; btmsa=η2‐Me3SiC2SiMe3) can be obtained from the hitherto unknown calcocenophane complex [C2H4(C5Me4)2Ca(THF)2] ( 1 ). Furthermore, a heterodiatomic bridging unit containing both, a dimethylsilyl and a methylene group was introduced to yield the ansa‐titanocene dichloride [Me2SiCH2(C5Me4)2TiCl2] ( 3 ‐Cl2) and the bis(trimethylsilyl)acetylene complex [Me2SiCH2(C5Me4)2Ti(η2‐Me3SiC2SiMe3)] ( 3 ‐btmsa). Besides, tetramethyldisilyl‐ and dimethylsilyl‐bridged metallocene complexes (structural motif 4 and 5 , respectively) were prepared. All ansa‐titanocene alkyne complexes were reacted with stoichiometric amounts of water; the hydrolysis products were isolated as model complexes for the investigation of the elemental steps of overall water splitting. Compounds 1 , 2 ‐btmsa, 2 ‐(OH)2, 3 ‐Cl2, 3 ‐btmsa, 4 ‐(OH)2, 3 ‐alkenyl and 5 ‐alkenyl were characterised by X‐ray diffraction analysis. 相似文献
11.
Reactions of 2‐Substituted Pyridines with Titanocenes and Zirconocenes: Coupling versus Dearomatisation
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Dr. Fabian Reiß Dr. Kai Altenburger Dr. Lisanne Becker Kathleen Schubert Dr. Haijun Jiao Dr. Anke Spannenberg Dr. Dirk Hollmann Dr. Perdita Arndt Prof. Dr. Uwe Rosenthal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(10):3361-3369
Reactions of group 4 metallocene sources with 2‐substituted pyridines were investigated to evaluate their coordination type between innocent and reductive dearomatisation as well as to probe the possibility for couplings. A dependence on the cyclopentadienyl ligands (Cp, Cp*), the metals (Ti, Zr), and the substrates (2‐phenyl‐, 2‐acetyl‐, and 2‐iminopyridine) was observed. While 2‐phenylpyridine is barely reactive, 2‐acetylpyridine reacts vigorously with the Cp‐substituted complexes and selectively with their Cp* analogues. With 2‐iminopyridine, in all cases selective reactions were observed. In the isolated [Cp2Ti], [Cp2Zr], and [Cp*2Zr] compounds the substrate coordinates by its pyridyl ring and the unsaturated side‐chain. Subsequently, the pyridine was dearomatised, which is most pronounced in the [Cp*2Zr] compounds. Using [Cp*2Ti] leads to the unexpected paramagnetic complexes [Cp*2TiIII(N,O‐acpy)] and [Cp*2TiIII(N,N′‐impy)]. This highlights the non‐innocent character of the pyridyl substrates. 相似文献
12.
Formation of Tri‐ and Tetranuclear Titanacycles through Decamethyltitanocene‐Mediated Intermolecular C–C Coupling of Dinitriles
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Dr. Lisanne Becker Dr. Perdita Arndt Dr. Anke Spannenberg Dr. Haijun Jiao Prof. Dr. Uwe Rosenthal 《Angewandte Chemie (International ed. in English)》2015,54(18):5523-5526
The reactions of [Cp*2Ti(η2‐Me3SiC2SiMe3)] (Cp*=η5‐pentamethylcyclopentadienyl) with various dicyano compounds were investigated. Nitrile–nitrile C? C couplings result in multinuclear complexes owing to the bifunctionality of the substrates. Applying 1,3‐ or 1,4‐dicyanobenzene led to tri‐ and tetranuclear complexes of the rare 1‐metalla‐2,5‐diaza‐cyclopenta‐2,4‐dienes. These are potential catalysts and were tested in the ring‐opening polymerization of ε‐caprolactone. The reaction with adiponitrile as alkyl dinitrile afforded a trinuclear 1‐metalla‐2,5‐diaza‐cyclopent‐3‐ene through additional protonation of the nitrogen atoms. The structure and bonding of the products were investigated by X‐ray crystallography and DFT analysis to understand the molecular organization in the macrocycles. 相似文献
13.
Vladimir V. Burlakov Marc A. Bach Marcus Klahn Perdita Arndt Wolfgang Baumann Anke Spannenberg Uwe Rosenthal 《Macromolecular Symposia》2006,236(1):48-53
The recently described reaction products of zirconacyclopropenes Cp′2Zr(η2-Me3SiC2SiMe3) and five-membered zirconacyclocumulenes (zirconacyclopenta-2,3,4-trienes) Cp*2Zr(η4-1,2,3,4-RC4R), Cp* = η5-pentamethylcyclopentadienyl, R = Me, Me3Si and Ph, with i-Bu2AlH are active catalysts in the polymerization of ethylene and in the ring opening polymerization of ε-caprolactone. Here we describe the different activity of these complexes after thermal activation or if additional i-Bu2AlH together with water are added. These results are compared to those which were obtained with the complexes Cp2Zr(η4-1,2,3,4-H2C4H2), rac-(EBTHI)ZrF2, rac-(EBTHI)ZrCl2, [rac-(EBTHI)Zr(H)(µ-H)]2 and rac (EBTHI)Zr(F)CH2-CH2(2-Py) after activation with i-Bu2AlH together with water. 相似文献
14.
Dr. Shubhankar Kumar Bose Dipak Kumar Roy Pritam Shankhari K. Yuvaraj Bijan Mondal Amrita Sikder Prof. Sundargopal Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(7):2337-2343
Room temperature photolysis of a triply‐bridged borylene complex, [(μ3‐BH)(Cp*RuCO)2(μ‐CO)Fe(CO)3] ( 1 a ; Cp*=C5Me5), in the presence of a series of alkynes, 1,2‐diphenylethyne, 1‐phenyl‐1‐propyne, and 2‐butyne led to the isolation of unprecedented vinyl‐borylene complexes (Z)‐[(Cp*RuCO)2(μ‐CO)B(CR)(CHR′)] ( 2 : R, R′=Ph; 3 : R=Me, R′=Ph; 4 : R, R′=Me). This reaction permits a hydroboration of alkyne through an anti ‐ Markovnikov addition. In stark contrast, in the presence of phenylacetylene, a metallacarborane, closo‐[1,2‐(Cp*Ru)2(μ‐CO)2{Fe2(CO)5}‐4‐Ph‐4,5‐C2BH2] ( 5 a) , is formed. A plausible mechanism has been proposed for the formation of vinyl‐borylene complexes, which is supported by density functional theory (DFT) methods. Furthermore, the calculated 11B NMR chemical shifts accurately reflect the experimentally measured shifts. All the new compounds have been characterized in solution by mass spectrometry and IR, 1H, 11B, and 13C NMR spectroscopies and the structural types were unequivocally established by crystallographic analysis of 2 , 5 a , and 5 b . 相似文献
15.
Paul‐Michael Pellny Vladimir V. Burlakov Wolfgang Baumann Anke Spannenberg Uwe Rosenthal 《无机化学与普通化学杂志》1999,625(6):910-918
The reactions of the bis(trimethylsilyl)acetylene permethylmetallocene complexes CpM(η2‐Me3SiC2SiMe3) (M = Ti ( 1 ), M = Zr ( 2 )) with H2O and CO2 were studied and compared to those of the corresponding metallocene complexes Cp2M(L)(η2‐Me3SiC2SiMe3) (M = Ti ( 3 ), L = – ; M = Zr, L = THF ( 4 )) to understand the influence of the ligands Cp(η5‐C5H5) and Cp*(η5‐C5Me5) as well as the metals titanium and zirconium on the reaction pathways and the obtained products. In the reaction of the permethyltitanocene complex 1 with water the dihydroxy complex CpTi(OH)2 ( 5 ) was formed. This product differs from the well‐known titanoxane Cp2TiOTiCp2 which was obtained by the reaction of the corresponding titanocene complex 3 with water. The reaction of the permethylzirconocene complex 2 with water gives the mononuclear alkenyl zirconocene hydroxide 6 . An analogous product was assumed as the first step in the reaction of the corresponding zirconocene complex 4 with water which ends up in a dinuclear zirconoxane. In the conversion of the permethylzirconocene complex 2 with carbon dioxide the mononuclear insertion product 7 was formed by coupling of carbon dioxide and the acetylene. In contrast, the corresponding zirconocene complex 4 affords, by an analogous reaction, a dinuclear complex. In additional experiments the known complex CpZr(η2‐PhC2SiMe3) ( 8 ) was prepared, starting from CpZrCl2 and Mg in the presence of PhC≡CSiMe3. This complex reacts with carbon dioxide resulting in a mixture of the regioisomeric zirconafuranones 9 a and 9 b . From these in the complex 9 a , having the SiMe3 group in β‐position to the metal, the Zr–C bond was quickly hydrolyzed by water to give the complex CpZr(OH)OC(=O)–C(SiMe3)=CHPh ( 10 a ) compared to complex ( 9 b ) which gives slowly the complex CpZr(OH)OC(=O)–CPh=CH(SiMe3) ( 10 b ). 相似文献
16.
Martin Piesch Stephan Reichl Michael Seidl Gbor Balzs Manfred Scheer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(46):16716-16721
Die Reaktion von [Cp′′′Co(η4‐P4)] ( 1 ) (Cp′′′=1,2,4‐tBu3C5H2) mit MeNHC (MeNHC=1,3,4,5‐tetramethylimidazol‐2‐ylidene) führt über eine NHC‐induzierte Phosphorkationen‐Abstraktion zum Ringkontraktionsprodukt [(MeNHC)2P][Cp′′′Co(η3‐P3)] ( 2 ), welches das erste Beispiel eines anionischen CoP3‐Komplexes repräsentiert. Solche von NHCs induzierten Ringkontraktionsreaktionen lassen sich ebenfalls auf Tripeldecker‐Sandwich‐Komplexe anwenden. So werden die Komplexe [(Cp*Mo)2(μ,η6:6‐E6)] ( 3 a , 3 b ) (Cp*=C5Me5; E=P, As) zu den Komplexen [(MeNHC)2E][(Cp*M)2(μ,η3:3‐E3)(μ,η2:2‐E2)] ( 4 a , 4 b ) transformiert, wobei 4 b das erste strukturell charakterisierte Beispiel eines NHC‐substituierten AsI‐Kations darstellt. Darüber hinaus führt die Reaktion des Vanadium‐Komplexes [(Cp*V)2(μ,η6:6‐P6)] ( 5 ) mit MeNHC zur Bildung der neuartigen Komplexe [(MeNHC)2P][(Cp*V)2(μ,η6:6‐P6)] ( 6 ), [(MeNHC)2P][(Cp*V)2(μ,η5:5‐P5)] ( 7 ) bzw. [(Cp*V)2(μ,η3:3‐P3)(μ,η1:1‐P{MeNHC})] ( 8 ). 相似文献
17.
R. Beckhaus M. Wagner V. V. Burlakov W. Baumann N. Peulecke A. Spannenberg R. Kempe U. Rosenthal 《无机化学与普通化学杂志》1998,624(1):129-134
The titanocene acetylene complex [Cp*2Ti(η2-Me3SiC≡CSiMe3)] ( 14 ) reacts with 1-alkynes such as phenylacetylene ( 15 a ), 1-hexyne ( 15 b ), 1-dodecyne ( 15 c ) and trimethylsilylacetylene ( 15 d ) by ligand exchange and proton shift, to yield exclusively the 1-alkenyltitanocene acetylides [Cp*2Ti(CH=CHR)(C≡CR)] ( 21 ) (R = Ph ( 21 a ), CH3(CH2)3 ( 21 b ), CH3(CH2)9 ( 21 c ), SiMe3 ( 21 d )). The X-ray structure of 21 a is presented. In reaction of acetylene HC≡CH ( 15 e ) with 14 other products are formed. However, no intermediates, like [Cp*2Ti(η2-RC≡CH)] ( 17 ), [Cp*2Ti(H)C≡CR] ( 17 ) or [Cp*2Ti=C=CHR] ( 22 ) in reactions of 14 with 15 are detectable. On the other hand, a stable titanocenehydride [Cp*2Ti(H)OCH3] ( 23 ) is obtained by oxidative addition of CH3OH with Cp*2Ti, generated from 14 . 相似文献
18.
Dr. Nicholas Arleth Dr. Michael T. Gamer Dr. Ralf Köppe Prof. Dr. Sergey N. Konchenko Martin Fleischmann Prof. Dr. Manfred Scheer Prof. Dr. Peter W. Roesky 《Angewandte Chemie (International ed. in English)》2016,55(4):1557-1560
Reduction of [Cp*Fe(η5‐As5)] with [Cp′′2Sm(thf)] (Cp′′=η5‐1,3‐(tBu)2C5H3) under various conditions led to [(Cp′′2Sm)(μ,η4:η4‐As4)(Cp*Fe)] and [(Cp′′2Sm)2As7(Cp*Fe)]. Both compounds are the first polyarsenides of the rare‐earth metals. [(Cp′′2Sm)(μ,η4:η4‐As4)(Cp*Fe)] is also the first d/f‐triple decker sandwich complex with a purely inorganic planar middle deck. The central As42? unit is isolobal with the 6π‐aromatic cyclobutadiene dianion (CH)42?. [(Cp′′2Sm)2As7(Cp*Fe)] contains an As73? cage, which has a norbornadiene‐like structure with two short As?As bonds in the scaffold. DFT calculations confirm all the structural observations. The As?As bond order inside the cyclo As4 ligand in [(Cp′′2Sm)(μ,η4:η4‐As4)(Cp*Fe)] was estimated to be in between an As?As single bond and a formally aromatic As42? system. 相似文献
19.
Tae‐Jin Kim Sung‐Kwan Kim Beom‐Jun Kim Ho‐Jin Son Jong Sok Hahn Minserk Cheong Prof. Mariusz Mitoraj Dr. Monika Srebro Łukasz Piękoś Artur Michalak Prof. Sang Ook Kang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(19):5630-5644
A series of mono‐, bis‐, and tris(phenoxy)–titanium(IV) chlorides of the type [Cp*Ti(2‐R? PhO)nCl3?n] (n=1–3; Cp*=pentamethylcyclopentadienyl) was prepared, in which R=Me, iPr, tBu, and Ph. The formation of each mono‐, bis‐, and tris(2‐alkyl‐/arylphenoxy) series was authenticated by structural studies on representative examples of the phenyl series including [Cp*Ti(2‐Ph? PhO)Cl2] ( 1 PhCl2 ), [Cp*Ti(2‐Ph? PhO)2Cl] ( 2 PhCl ), and [Cp*Ti(2‐Ph? PhO)3] ( 3 Ph ). The metal‐coordination geometry of each compound is best described as pseudotetrahedral with the Cp* ring and the 2‐Ph? PhO and chloride ligands occupying three leg positions in a piano‐stool geometry. The mean Ti? O distances, observed with an increasing number of 2‐Ph? PhO groups, are 1.784(3), 1.802(4), and 1.799(3) Å for 1 PhCl2 , 2 PhCl , and 3 Ph , respectively. All four alkyl/aryl series with Me, iPr, tBu, and Ph substituents were tested for ethylene homopolymerization after activation with Ph3C+[B(C6F5)4]? and modified methyaluminoxane (7% aluminum in isopar E; mMAO‐7) at 140 °C. The phenyl series showed much higher catalytic activity, which ranged from 43.2 and 65.4 kg (mmol of Ti?h)?1, than the Me, iPr, and tBu series (19.2 and 36.6 kg (mmol of Ti?h)?1). Among the phenyl series, the bis(phenoxide) complex of 2 PhCl showed the highest activity of 65.4 kg (mmol of Ti?h)?1. Therefore, the catalyst precursors of the phenyl series were examined by treating them with a variety of alkylating reagents, such as trimethylaluminum (TMA), triisobutylaluminum (TIBA), and methylaluminoxane (MAO). In all cases, 2 PhCl produced the most catalytically active alkylated species, [Cp*Ti(2‐Ph? PhO)MeCl]. This enhancement was further supported by DFT calculations based on the simplified model with TMA. 相似文献
20.
Martin Piesch Stephan Reichl Michael Seidl Gbor Balzs Manfred Scheer 《Angewandte Chemie (International ed. in English)》2019,58(46):16563-16568
The reaction of [Cp′′′Co(η4‐P4)] ( 1 ) (Cp′′′=1,2,4‐tBu3C5H2) with MeNHC (MeNHC=1,3,4,5‐tetramethylimidazol‐2‐ylidene) leads through NHC‐induced phosphorus cation abstraction to the ring contraction product [(MeNHC)2P][Cp′′′Co(η3‐P3)] ( 2 ), which represents the first example of an anionic CoP3 complex. Such NHC‐induced ring contraction reactions are also applicable for triple‐decker sandwich complexes. The complexes [(Cp*Mo)2(μ,η6:6‐E6)] ( 3 a , 3 b ) (Cp*=C5Me5; E=P, As) can be transformed to the complexes [(MeNHC)2E][(Cp*M)2(μ,η3:3‐E3)(μ,η2:2‐E2)] ( 4 a , 4 b ), with 4 b representing the first structurally characterized example of an NHC‐substituted AsI cation. Further, the reaction of the vanadium complex [(Cp*V)2(μ,η6:6‐P6)] ( 5 ) with MeNHC results in the formation of the unprecedented complexes [(MeNHC)2P][(Cp*V)2(μ,η6:6‐P6)] ( 6 ), [(MeNHC)2P][(Cp*V)2(μ,η5:5‐P5)] ( 7 ) and [(Cp*V)2(μ,η3:3‐P3)(μ,η1:1‐P{MeNHC})] ( 8 ). 相似文献