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1.
Synthesis,Structure, and Reactivity of a Gold Carbenoid Complex That Lacks Heteroatom Stabilization 下载免费PDF全文
Robert J. Harris Prof. Ross A. Widenhoefer 《Angewandte Chemie (International ed. in English)》2014,53(35):9369-9371
Hydride abstraction from the neutral gold cycloheptatrienyl complex [( P )Au(η1‐C7H7)] ( P =P(tBu)2(o‐biphenyl)) with triphenylcarbenium tetrafluoroborate at ?80 °C led to the isolation of the cationic gold cycloheptatrienylidene complex [( P )Au(η1‐C7H6)]+ BF4? in 52 % yield, which was characterized in solution and by single‐crystal X‐ray diffraction. This cycloheptatrienylidene complex represents the first example of a gold carbenoid complex that lacks conjugated heteroatom stabilization of the electron‐deficient C1 carbon atom. The cycloheptatrienylidene ligand of this complex is reactive; it can be reduced by mild hydride donors, and converted to tropone in the presence of pyridine N‐oxide. 相似文献
2.
Nana Kim Prof. Ross A. Widenhoefer 《Angewandte Chemie (International ed. in English)》2018,57(17):4722-4726
Methoxide abstraction from gold acetylide complexes of the form (L)Au[η1‐C≡CC(OMe)ArAr′] (L=IPr, P(tBu)2(ortho‐biphenyl); Ar/Ar′=C6H4X where X=H, Cl, Me, OMe) with trimethylsilyl trifluoromethanesulfonate (TMSOTf) at ?78 °C resulted in the formation of the corresponding cationic gold diarylallenylidene complexes [(L)Au=C=C=CArAr′]+ OTf? in ≥85±5 % yield according to 1H NMR analysis. 13C NMR and IR spectroscopic analysis of these complexes established the arene‐dependent delocalization of positive charge on both the C1 and C3 allenylidene carbon atoms. The diphenylallenylidene complex [(IPr)Au=C=C=CPh2]+ OTf? reacted with heteroatom nucleophiles at the allenylidene C1 and/or C3 carbon atom. 相似文献
3.
Dr. Tetsuya Fukuda Dr. Hisako Hashimoto Prof. Dr. Shigeyoshi Sakaki Prof. Dr. Hiromi Tobita 《Angewandte Chemie (International ed. in English)》2016,55(1):188-192
Treatment of pyridine‐stabilized silylene complexes [(η5‐C5Me4R)(CO)2(H)W?SiH(py)(Tsi)] (R=Me, Et; py=pyridine; Tsi=C(SiMe3)3) with an N‐heterocyclic carbene MeIiPr (1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) caused deprotonation to afford anionic silylene complexes [(η5‐C5Me4R)(CO)2W?SiH(Tsi)][HMeIiPr] (R=Me ( 1‐Me ); R=Et ( 1‐Et )). Subsequent oxidation of 1‐Me and 1‐Et with pyridine‐N‐oxide (1 equiv) gave anionic η2‐silaaldehydetungsten complexes [(η5‐C5Me4R)(CO)2W{η2‐O?SiH(Tsi)}][HMeIiPr] (R=Me ( 2‐Me ); R=Et ( 2‐Et )). The formation of an unprecedented W‐Si‐O three‐membered ring was confirmed by X‐ray crystal structure analysis. 相似文献
4.
Diimido, Imido Oxo, Dioxo, and Imido Alkylidene Halfsandwich Compounds via Selective Hydrolysis and α—H Abstraction in Molybdenum(VI) and Tungsten(VI) Organyl Complexes Organometal imides [(η5‐C5R5)M(NR′)2Ph] (M = Mo, W, R = H, Me, R′ = Mes, tBu) 4 — 8 can be prepared by reaction of halfsandwich complexes [(η5‐C5R5)M(NR′)2Cl] with phenyl lithium in good yields. Starting from phenyl complexes 4 — 8 as well as from previously described methyl compounds [(η5‐C5Me5)M(NtBu)2Me] (M = Mo, W), reactions with aqueous HCl lead to imido(oxo) methyl and phenyl complexes [(η5‐C5Me5)M(NtBu)(O)(R)] M = Mo, R = Me ( 9 ), Ph ( 10 ); M = W, R = Ph ( 11 ) and dioxo complexes [(η5‐C5Me5)M(O)2(CH3)] M = Mo ( 12 ), M = W ( 13 ). Hydrolysis of organometal imides with conservation of M‐C σ and π bonds is in fact an attractive synthetic alternative for the synthesis of organometal oxides with respect to known strategies based on the oxidative decarbonylation of low valent alkyl CO and NO complexes. In a similar manner, protolysis of [(η5‐C5H5)W(NtBu)2(CH3)] and [(η5‐C5Me5)Mo(NtBu)2(CH3)] by HCl gas leads to [(η5‐C5H5)W(NtBu)Cl2(CH3)] 14 und [(η5‐C5Me5)Mo(NtBu)Cl2(CH3)] 15 with conservation of the M‐C bonds. The inert character of the relatively non‐polar M‐C σ bonds with respect to protolysis offers a strategy for the synthesis of methyl chloro complexes not accessible by partial methylation of [(η5‐C5R5)M(NR′)Cl3] with MeLi. As pure substances only trimethyl compounds [(η5‐C5R5)M(NtBu)(CH3)3] 16 ‐ 18 , M = Mo, W, R = H, Me, are isolated. Imido(benzylidene) complexes [(η5‐C5Me5)M(NtBu)(CHPh)(CH2Ph)] M = Mo ( 19 ), W ( 20 ) are generated by alkylation of [(η5‐C5Me5)M(NtBu)Cl3] with PhCH2MgCl via α‐H abstraction. Based on nmr data a trend of decreasing donor capability of the ligands [NtBu]2— > [O]2— > [CHR]2— ? 2 [CH3]— > 2 [Cl]— emerges. 相似文献
5.
Reactivity of TpMe2‐Supported Yttrium Alkyl Complexes toward Aromatic N‐Heterocycles: Ring‐Opening or CC Bond Formation Directed by CH Activation 下载免费PDF全文
Dr. Weiyin Yi Prof. Dr. Jie Zhang Shujian Huang Prof. Dr. Linhong Weng Prof. Dr. Xigeng Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):867-876
Unusual chemical transformations such as three‐component combination and ring‐opening of N‐heterocycles or formation of a carbon–carbon double bond through multiple C–H activation were observed in the reactions of TpMe2‐supported yttrium alkyl complexes with aromatic N‐heterocycles. The scorpionate‐anchored yttrium dialkyl complex [TpMe2Y(CH2Ph)2(THF)] reacted with 1‐methylimidazole in 1:2 molar ratio to give a rare hexanuclear 24‐membered rare‐earth metallomacrocyclic compound [TpMe2Y(μ‐N,C‐Im)(η2‐N,C‐Im)]6 ( 1 ; Im=1‐methylimidazolyl) through two kinds of C–H activations at the C2‐ and C5‐positions of the imidazole ring. However, [TpMe2Y(CH2Ph)2(THF)] reacted with two equivalents of 1‐methylbenzimidazole to afford a C–C coupling/ring‐opening/C–C coupling product [TpMe2Y{η3‐(N,N,N)‐N(CH3)C6H4NHCH?C(Ph)CN(CH3)C6H4NH}] ( 2 ). Further investigations indicated that [TpMe2Y(CH2Ph)2(THF)] reacted with benzothiazole in 1:1 or 1:2 molar ratio to produce a C–C coupling/ring‐opening product {(TpMe2)Y[μ‐η2:η1‐SC6H4N(CH?CHPh)](THF)}2 ( 3 ). Moreover, the mixed TpMe2/Cp yttrium monoalkyl complex [(TpMe2)CpYCH2Ph(THF)] reacted with two equivalents of 1‐methylimidazole in THF at room temperature to afford a trinuclear yttrium complex [TpMe2CpY(μ‐N,C‐Im)]3 ( 5 ), whereas when the above reaction was carried out at 55 °C for two days, two structurally characterized metal complexes [TpMe2Y(Im‐TpMe2)] ( 7 ; Im‐TpMe2=1‐methyl‐imidazolyl‐TpMe2) and [Cp3Y(HIm)] ( 8 ; HIm=1‐methylimidazole) were obtained in 26 and 17 % isolated yields, respectively, accompanied by some unidentified materials. The formation of 7 reveals an uncommon example of construction of a C?C bond through multiple C–H activations. 相似文献
6.
Dr. Weiyin Yi Jie Zhang Prof. Dr. Fangjun Zhang Yin Zhang Dr. Zhenxia Chen Prof. Dr. Xigeng Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):11975-11983
A series of unusual chemical‐bond transformations were observed in the reactions of high active yttrium? dialkyl complexes with unsaturated small molecules. The reaction of scorpionate‐anchored yttrium? dibenzyl complex [TpMe2Y(CH2Ph)2(thf)] ( 1 , TpMe2=tri(3,5‐dimethylpyrazolyl)borate) with phenyl isothiocyanate led to C?S bond cleavage to give a cubane‐type yttrium–sulfur cluster, {TpMe2Y(μ3‐S)}4 ( 2 ), accompanied by the elimination of PhN?C(CH2Ph)2. However, compound 1 reacted with phenyl isocyanate to afford a C(sp3)? H activation product, [TpMe2Y(thf){μ‐η1:η3‐OC(CHPh)NPh}{μ‐η3:η2‐OC(CHPh)NPh}YTpMe2] ( 3 ). Moreover, compound 1 reacted with phenylacetonitrile at room temperature to produce γ‐deprotonation product [(TpMe2)2Y]+[TpMe2Y(N=C?CHPh)3]? ( 6 ), in which the newly formed N?C?CHPh ligands bound to the metal through the terminal nitrogen atoms. When this reaction was carried out in toluene at 120 °C, it gave a tandem γ‐deprotonation/insertion/partial‐TpMe2‐degradation product, [(TpMe2Y)2(μ‐Pz)2{μ‐η1:η3‐NC(CH2Ph)CHPh}] ( 7 , Pz=3,5‐dimethylpyrazolyl). 相似文献
7.
Formal Gold‐to‐Gold Transmetalation of an Alkynyl Group Mediated by Palladium: A Bisalkynyl Gold Complex as a Ligand to Palladium 下载免费PDF全文
Alberto Toledo Dr. Isabel Meana Prof. Dr. Ana C. Albéniz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13216-13220
The reaction of [Au(C?C?n‐Bu)]n with [Pd(η3‐allyl)Cl(PPh3)] results in a ligand and alkynyl rearrangement, and leads to the heterometallic complex [Pd(η3‐allyl){Au(C?C?n‐Bu)2}]2 ( 3 ) with an unprecedented bridging bisalkynyl–gold ligand coordinated to palladium. This is a formal gold‐to‐gold transmetalation that occurs through reversible alkynyl transmetalations between gold and palladium. 相似文献
8.
Roxana M. Bîrzoi Dr. Delia Bugnariu Dr. Rafael Guerrero Gimeno Dr. Daniela Lungu Vera Zota Dr. Constantin Daniliuc Dr. Peter G. Jones Prof. Dr. Zoltán Benkõ Dr. László Könczöl László Nyulászi Prof. Dr. Rainer Bartsch Dr. Wolf‐W. du Mont Prof. Dr. Edgar Niecke Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(16):4843-4851
Deprotonation of aminophosphaalkenes (RMe2Si)2C?PN(H)(R′) (R=Me, iPr; R′=tBu, 1‐adamantyl (1‐Ada), 2,4,6‐tBu3C6H2 (Mes*)) followed by reactions of the corresponding Li salts Li[(RMe2Si)2C?P(M)(R′)] with one equivalent of the corresponding P‐chlorophosphaalkenes (RMe2Si)2C?PCl provides bisphosphaalkenes (2,4‐diphospha‐3‐azapentadienes) [(RMe2Si)2C?P]2NR′. The thermally unstable tert‐butyliminobisphosphaalkene [(Me3Si)2C?P]2NtBu ( 4 a ) undergoes isomerisation reactions by Me3Si‐group migration that lead to mixtures of four‐membered heterocyles, but in the presence of an excess amount of (Me3Si)2C?PCl, 4 a furnishes an azatriphosphabicyclohexene C3(SiMe3)5P3NtBu ( 5 ) that gave red single crystals. Compound 5 contains a diphosphirane ring condensed with an azatriphospholene system that exhibits an endocylic P?C double bond and an exocyclic ylidic P(+)? C(?)(SiMe3)2 unit. Using the bulkier iPrMe2Si substituents at three‐coordinated carbon leads to slightly enhanced thermal stability of 2,4‐diphospha‐3‐azapentadienes [(iPrMe2Si)2C?P]2NR′ (R′=tBu: 4 b ; R′=1‐Ada: 8 ). According to a low‐temperature crystal‐structure determination, 8 adopts a non‐planar structure with two distinctly differently oriented P?C sites, but 31P NMR spectra in solution exhibit singlet signals. 31P NMR spectra also reveal that bulky Mes* groups (Mes*=2,4,6‐tBu3C6H2) at the central imino function lead to mixtures of symmetric and unsymmetric rotamers, thus implying hindered rotation around the P? N bonds in persistent compounds [(RMe2Si)2C?P]2NMes* ( 11 a , 11 b ). DFT calculations for the parent molecule [(H3Si)2C?P]2NCH3 suggest that the non‐planar distortion of compound 8 will have steric grounds. 相似文献
9.
Dr. Laura Rubio‐Pérez Dipl.‐Chem. Ramón Azpíroz Dr. Andrea Di Giuseppe Dr. Victor Polo Dr. Ricardo Castarlenas Prof. Jesús J. Pérez‐Torrente Prof. Luis A. Oro 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(45):15304-15314
A general regioselective rhodium‐catalyzed head‐to‐tail dimerization of terminal alkynes is presented. The presence of a pyridine ligand (py) in a Rh–N‐heterocyclic‐carbene (NHC) catalytic system not only dramatically switches the chemoselectivity from alkyne cyclotrimerization to dimerization but also enhances the catalytic activity. Several intermediates have been detected in the catalytic process, including the π‐alkyne‐coordinated RhI species [RhCl(NHC)(η2‐HC?CCH2Ph)(py)] ( 3 ) and [RhCl(NHC){η2‐C(tBu)?C(E)CH?CHtBu}(py)] ( 4 ) and the RhIII–hydride–alkynyl species [RhClH{? C?CSi(Me)3}(IPr)(py)2] ( 5 ). Computational DFT studies reveal an operational mechanism consisting of sequential alkyne C? H oxidative addition, alkyne insertion, and reductive elimination. A 2,1‐hydrometalation of the alkyne is the more favorable pathway in accordance with a head‐to‐tail selectivity. 相似文献
10.
Robert J. Harris Ross A. Widenhoefer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(35):9523-9525
Hydride abstraction from the neutral gold cycloheptatrienyl complex [( P )Au(η1‐C7H7)] ( P =P(tBu)2(o‐biphenyl)) with triphenylcarbenium tetrafluoroborate at −80 °C led to the isolation of the cationic gold cycloheptatrienylidene complex [( P )Au(η1‐C7H6)]+ BF4− in 52 % yield, which was characterized in solution and by single‐crystal X‐ray diffraction. This cycloheptatrienylidene complex represents the first example of a gold carbenoid complex that lacks conjugated heteroatom stabilization of the electron‐deficient C1 carbon atom. The cycloheptatrienylidene ligand of this complex is reactive; it can be reduced by mild hydride donors, and converted to tropone in the presence of pyridine N‐oxide. 相似文献
11.
Olga Crespo M. Concepcin Gimeno Peter G. Jones Antonio Laguna 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):46-47
The title compound, 7‐[(Ph2P)Au(PPh3)]‐8‐(CH3)‐7,8‐nido‐C2B9H10]·0.5CH2Cl2 or [Au(C15H23B9P)(C18H15P)]·0.5CH2Cl2, is the first reported gold derivative of the ligand [7‐(Ph2P)‐8‐(CH3)‐7,8‐nido‐C2B9H10]?. It has a mononuclear structure with the gold centre in an essentially linear coordination [P—Au—P 174.041 (15)°]. The open C2B3 face contains one H atom that is strongly bonded to the central B atom and semi‐bridging to a neighbouring B atom [B—H distances 1.070 (16) and 1.45 (3) Å]. 相似文献
12.
13.
Rachel E. M. Brooner Dr. Timothy J. Brown Prof. Ross A. Widenhoefer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(25):8276-8284
Cationic, two‐coordinate triphenylphosphine–gold(I)–π complexes of the form [(PPh3)Au(π ligand)]+ SbF6? (π ligand=4‐methylstyrene, 1? SbF6), 2‐methyl‐2‐butene ( 3? SbF6), 3‐hexyne ( 6? SbF6), 1,3‐cyclohexadiene ( 7? SbF6), 3‐methyl‐1,2‐butadiene ( 8? SbF6), and 1,7‐diphenyl‐3,4‐heptadiene ( 10? SbF6) were generated in situ from reaction of [(PPh3)AuCl], AgSbF6, and π ligand at ?78 °C and were characterized by low‐temperature, multinuclear NMR spectroscopy without isolation. The π ligands of these complexes were both weakly bound and kinetically labile and underwent facile intermolecular exchange with free ligand (ΔG≠≈9 kcal mol?1 in the case of 6? SbF6) and competitive displacement by weak σ donors, such as trifluoromethane sulfonate. Triphenylphosphine–gold(I)–π complexes were thermally unstable and decomposed above ?20 °C to form the bis(triphenylphosphine) gold cation [(PPh3)2Au]+SbF6? ( 2? SbF6). 相似文献
14.
Abdallah Zeineddine Dr. Feriel Rekhroukh Dr. E. Daiann Sosa Carrizo Sonia Mallet‐Ladeira Dr. Karinne Miqueu Dr. Abderrahmane Amgoune Dr. Didier Bourissou 《Angewandte Chemie (International ed. in English)》2018,57(5):1306-1310
The [(P,P)Au=C(Ph)CO2Et]+ complex 3 [where (P,P) is an o‐carboranyl diphosphine ligand] was prepared by diazo decomposition at ?40 °C. It is the first α‐oxo gold carbene complex to be characterized. Its crystallographic structure was determined and DFT calculations have been performed, unraveling the key influence of the chelating (P,P) ligand. The gold center is tricoordinate and the electrophilicity of the carbene center is decreased. Complex 3 mimics transient α‐oxo gold carbenes in a series of catalytic transformations, and provides support for the critical role of electrophilicity in the chemoselectivity of phenol functionalization (O?H vs. C?H insertion). 相似文献
15.
Dr. Robert J. Harris Kohki Nakafuku Dr. Alethea N. Duncan Robert G. Carden Dr. Jacob C. Timmerman Prof. Dr. Ross A. Widenhoefer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(40):10377-10386
The mechanism of the intermolecular hydroamination of 3-methylbuta-1,2-diene ( 1 ) with N-methylaniline ( 2 ) catalyzed by (IPr)AuOTf has been studied by employing a combination of kinetic analysis, deuterium labelling studies, and in situ spectral analysis of catalytically active mixtures. The results of these and additional experiments are consistent with a mechanism for hydroamination involving reversible, endergonic displacement of N-methylaniline from [(IPr)Au(NHMePh)]+ ( 4 ) by allene to form the cationic gold π-C1,C2-allene complex [(IPr)Au(η2-H2C=C=CMe2)]+ ( I ), which is in rapid, endergonic equilibrium with the regioisomeric π-C2,C3-allene complex [(IPr)Au(η2-Me2C=C=CH2)]+ ( I′ ). Rapid and reversible outer-sphere addition of 2 to the terminal allene carbon atom of I′ to form gold vinyl complex (IPr)Au[C(=CH2)CMe2NMePh] ( II ) is superimposed on the slower addition of 2 to the terminal allene carbon atom of I to form gold vinyl complex (IPr)Au[C(=CMe2)CH2NMePh] ( III ). Selective protodeauration of III releases N-methyl-N-(3-methylbut-2-en-1-yl)aniline ( 3 a ) with regeneration of 4 . At high conversion, gold vinyl complex II is competitively trapped by an (IPr)Au+ fragment to form the cationic bis(gold) vinyl complex {[(IPr)Au]2[C(=CH2)CMe2NMePh]}+ ( 6 ). 相似文献
16.
Herbert Schumann Esther C. E. Rosenthal Jrg Demtschuk Stefan Mühle 《无机化学与普通化学杂志》2000,626(10):2161-2166
Organometallic Compounds of the Lanthanides. 139 Mixed Sandwich Complexes of the 4 f Elements: Enantiomerically Pure Cyclooctatetraenyl Cyclopentadienyl Complexes of Samarium and Lutetium with Donor‐Functionalized Cyclopentadienyl Ligands The reactions of [K{(S)‐C5H4CH2CH(Me)OMe}], [K{(S)‐C5H4CH2CH(Me)NMe2}] and [K{(S)‐C5H4CH(Ph)CH2NMe2}] with the cyclooctatetraenyl lanthanide chlorides [(η8‐C8H8)Ln(μ‐Cl)(THF)]2 (Ln = Sm, Lu) yield the mixed cyclooctatetraenyl cyclopentadienyl lanthanide complexes [(η8‐C8H8)Sm{(S)‐η5 : η1‐C5H4CH2CH(Me)OMe}] ( 1 a ), [(η8‐C8H8)Ln{(S)‐η5 : η1‐C5H4CH2CH(Me)NMe2}] (Ln = Sm ( 2 a ), Lu ( 2 b )) and [(η8‐C8H8)Ln{(S)‐η5 : η1‐C5H4CH(Ph)CH2NMe2}] (Ln = Sm ( 3 a ), Lu ( 3 b )). For comparison, the achiral compounds [(η8‐C8H8)Ln{η5 : η1‐C5H4CH2CH2NMe2}] (Ln = Sm ( 4 a ), Lu ( 4 b )) are synthesized in an analogous manner. 1H‐, 13C‐NMR‐, and mass spectra of all new compounds as well as the X‐ray crystal structures of 3 b and 4 b are discussed. 相似文献
17.
CH Bond Activation during and after the Reactions of a Metallacyclic Amide with Silanes: Formation of a μ‐Alkylidene Hydride Complex,Its H–D Exchange,and β‐H Abstraction by a Hydride Ligand 下载免费PDF全文
Li Wang Seth C. Hunter Zhimin Song Dr. Carlos A. Steren Tianniu Chen Prof. Dr. Zhenhong Wei Prof. Dr. Hu Cai Prof. Dr. Zi‐Ling Xue 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(20):6033-6039
Metallacyclic complex [(Me2N)3Ta(η2‐CH2SiMe2NSiMe3)] ( 3 ) undergoes C?H activation in its reaction with H3SiPh to afford a Ta/μ‐alkylidene/hydride complex, [(Me2N)2{(Me3Si)2N}Ta(μ‐H)2(μ‐C‐η2‐CHSiMe2NSiMe3)Ta(NMe2)2] ( 4 ). Deuterium‐labeling studies with [D3]SiPh show H–D exchange between the Ta?D ?Ta unit and all methyl groups in [(Me2N)2{(Me3Si)2N}Ta(μ‐D)2(μ‐C‐η2‐CHSiMe2NSiMe3)Ta(NMe2)2] ([D2]‐ 4 ) to give the partially deuterated complex [Dn]‐ 4 . In addition, 4 undergoes β‐H abstraction between a hydride and an NMe2 ligand and forms a new complex [(Me2N){(Me3Si)2N}Ta(μ‐H)(μ‐N‐η2‐C,N‐CH2NMe)(μ‐C‐η2‐C,N‐CHSiMe2NSiMe3)Ta(NMe2)2] ( 5 ) with a cyclometalated, η2‐imine ligand. These results indicate that there are two simultaneous processes in [Dn]‐ 4 : 1) H–D exchange through σ‐bond metathesis, and 2) H?D elimination through β‐H abstraction (to give [Dn]‐ 5 ). Both 4 and 5 have been characterized by single‐crystal X‐ray diffraction studies. 相似文献
18.
The reactions of alkyn‐1‐yl(vinyl)silanes R2Si[C?C‐Si(H)Me2]CH?CH2 [R = Me (1a), Ph (1b)], Me2Si[C?C‐Si(Br)Me2]CH?CH2 (2a), and of alkyn‐1‐yl(allyl)silanes R2Si[C?C‐Si(H)Me2]CH2CH?CH2 (R = Me (3a), R = Ph (3b)] with 9‐borabicyclo[3.3.1]nonane in a 1:1 ratio afford in high yield the 1‐silacyclopent‐2‐ene derivatives 4a, b and 5a, and the 1‐silacyclohex‐2‐ene derivatives 6a, b, respectively, all of which bear a functionally substituted silyl group in 2‐position and the boryl group in 3‐position. This is the result of selective intermolecular 1,2‐hydroboration of the vinyl or allyl group, followed by intramolecular 1,1‐organoboration of the alkynyl group. In the cases of 4a, b, potential electron‐deficient Si? H? B bridges are absent or extremely weak, whereas in 6a,b the existence of Si? H? B bridges is evident from the NMR spectroscopic data (1H, 11B, 13C and 29Si NMR). The molecular structure of 4b was determined by X‐ray analysis. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
19.
Reaction of a labile tungsten nitrile complex, [(Cp*)W(CO)2(NCMe)Me] (Cp*=η5‐C5Me5), with H3SiC(SiMe3)3 gave the hydrido(hydrosilylene) complex [(Cp*)(CO)2(H)W?Si(H){C(SiMe3)3}] ( 1a ). The hydrido(silylene) complex [(η5‐C5Me4Et)(CO)2(H)W?SiMes2] ( 2 ) (Mes=2,4,6‐Me‐C6H2) was synthesized by a similar reaction with H2SiMes2. There is a strong interligand interaction between the hydrido and silylene ligands of these complexes; this was confirmed by a neutron diffraction study of [D2] 1b , that is, the deuterido and η5‐C5Me4Et derivative of 1a . The exchange between the W? H and the Si? D groups was observed in the deuterido complex [D] 1a . This H/D exchange proceeded slowly at room temperature, but very rapidly under UV irradiation. Variable‐temperature NMR spectroscopy measurements show the dynamic behavior of carbonyl ligands in 1a . Complex 1a reacted with acetone at room temperature to give mainly a hydrosilylation product, [(Cp*)(CO)2(H)W?Si(OiPr){C(SiMe3)3}] ( 3a ), along with a siloxy complex, [(Cp*)(CO)2WO(Si(H)iPr{C(SiMe3)3})] ( 4a ). At low temperature, a different reaction, namely, α‐H abstraction, proceeded to give an equilibrium mixture of 1a and a dihydrido(silyl) complex, [(Cp*)(CO)2(H)2W(Si(H){OC(?CH2)Me}{C(SiMe3)3})] ( 5 ). 相似文献
20.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(17):4812-4816
Methoxide abstraction from gold acetylide complexes of the form (L)Au[η1‐C≡CC(OMe)ArAr′] (L=IPr, P(tBu)2(ortho‐biphenyl); Ar/Ar′=C6H4X where X=H, Cl, Me, OMe) with trimethylsilyl trifluoromethanesulfonate (TMSOTf) at −78 °C resulted in the formation of the corresponding cationic gold diarylallenylidene complexes [(L)Au=C=C=CArAr′]+ OTf− in ≥85±5 % yield according to 1H NMR analysis. 13C NMR and IR spectroscopic analysis of these complexes established the arene‐dependent delocalization of positive charge on both the C1 and C3 allenylidene carbon atoms. The diphenylallenylidene complex [(IPr)Au=C=C=CPh2]+ OTf− reacted with heteroatom nucleophiles at the allenylidene C1 and/or C3 carbon atom. 相似文献