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1.
《应用有机金属化学》2017,31(10)
We describe the reaction of anion [RhCl6]3− with a series of hydantoin ligands (HL1, HL2 and HL3 = 5‐methyl‐5‐(2‐, 3‐ and 4‐pyridyl)‐2,4‐imidazolidenedione, respectively). Based on spectroscopic, cyclic voltammetric, elemental and MS analyses, the complexes have the general formula K[RhCl2(L1)2] ( 1 ), cis ‐ and trans ‐K[RhCl4(HL2)2] ( 2a and 2b ) and cis ‐ and trans ‐K[RhCl4(HL3)2] ( 3a and 3b ). Complexes 2a , 2b , 3a and 3b were characterized successfully using infrared, 1H NMR and 13C NMR spectral analyses. Dissolution of complex 1 in dimethylsulfoxide (DMSO) led to elimination of one KL1 ligand and coordination of two DMSO molecules as ligands and transformation of this complex to cis ‐ and trans ‐[RhCl2L1(DMSO)2] ( 1a and 1b ). Recrystallization led to separation and isolation of crystals of 1a from the initial mixture. X‐ray analysis results showed that this complex was crystallized as solvated complex cis ‐[RhCl2L1(DMSO)2]DMSO. The catalytic activity of these complexes was then evaluated for the hydrogenation of various ketones. 相似文献
2.
Alexander Bechtoldt Hans‐Wolfram Lerner Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(6):448-451
The aurophilicity exhibited by AuI complexes depends strongly on the nature of the supporting ligands present and the length of the Au–element (Au—E) bond may be used as a measure of the donor–acceptor properties of the coordinated ligands. A binuclear iron–gold complex, [1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene‐2κC2]dicarbonyl‐1κ2C‐(1η5‐cyclopentadienyl)gold(I)iron(II)(Au—Fe) benzene trisolvate, [AuFe(C5H5)(C27H36N2)(CO)2]·3C6H6, was prepared by reaction of K[CpFe(CO)2] (Cp is cyclopentadienyl) with (NHC)AuCl [NHC = 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]. In addition to the binuclear complex, the asymmetric unit contains three benzene solvent molecules. This is the first example of a two‐coordinated Au atom bonded to an Fe and a C atom of an N‐heterocyclic carbene. 相似文献
3.
Ming Zhang Xiaoli Liu Chaojun Shi Chunxia Ren Yuqiang Ding Herbert W. Roesky 《无机化学与普通化学杂志》2008,634(10):1755-1758
Treatment of N‐heterocyclic silylene Si[N(tBu)CH]2 ( 1 ) and [(η3‐C3H5)PdCl]2 in toluene led to the formation of the mononuclear complex (η3‐C3H5)Pd{Si[N(tBu)CH]2}Cl ( 3 ), the silicon analogue to N‐heterocyclic carbene complex (η3‐C3H5)Pd{C[N(tBu)CH]2}Cl ( 2 ). Complex 3 was characterized with 1H NMR and 13C NMR. Investigation shows that (η3‐C3H5)Pd{Si[N(tBu)CH]2}Cl is an active catalyst for Heck coupling reaction of styrene with aryl bromides. 相似文献
4.
The sequential reaction of the amino(trimethylsilyl)carbene complex [(CO)5W=C(NH2)C≡CSiMe3] ( 1 ) with nBuLi and [I‐Fe(CO)2Cp] affords the C(carbene)‐N bridged heterobinuclear complex [(CO)5W=C{NHFe(CO)2Cp}C≡CSiMe3] ( 2 ). Desilylation of 1 is achieved by treatment with KF in THF/MeOH. From the reaction of the resulting complex [(CO)5W=C(NH2)C≡CH] ( 3 ) with nBuLi and [I‐Fe(CO)2Cp] two binuclear WFe compounds in a ratio of approximately 1:1 are obtained: the C(carbene)‐C≡C bridged complex 4 and the C(carbene)‐N bridged complex 5 . Repetition of the deprotonation/metallation sequence yields the trinuclear WFe2 complex 6 . One Fe(CO)2Cp fragment in 6 is bonded to the amino group and the other one to the terminal carbon atom of the ethynyl substituent. The analogous reaction of 3 with nBuLi and [Br‐Ni(PMe2Ph)2Mes] gives a ca. 1:1 mixture of two heterobinuclear complexes ( 7 and 8 ). Complex 7 is bridged by the C(carbene)‐C≡C and complex 8 by the C(carbene)‐N fragment. Subsequent reaction of 7 with BuLi and [Br‐Ni(PMe2Ph)2Mes] finally affords the trinuclear WNi2 complex 9 related to 6 . The solid‐state structure of 2 is established by an X‐ray diffraction analysis. The spectroscopic data of the bi‐ and trinuclear complexes indicate electronic communication between the metal centers through the bridging group. 相似文献
5.
Dr. Erli Lu Dr. Oliver J. Cooper Dr. Jonathan McMaster Dr. Floriana Tuna Prof. Eric J. L. McInnes Dr. William Lewis Prof. Alexander J. Blake Prof. Stephen T. Liddle 《Angewandte Chemie (International ed. in English)》2014,53(26):6696-6700
We report the uranium(VI) carbene imido oxo complex [U(BIPMTMS)(NMes)(O)(DMAP)2] ( 5 , BIPMTMS=C(PPh2NSiMe3)2; Mes=2,4,6‐Me3C6H2; DMAP=4‐(dimethylamino)pyridine) which exhibits the unprecedented arrangement of three formal multiply bonded ligands to one metal center where the coordinated heteroatoms derive from different element groups. This complex was prepared by incorporation of carbene, imido, and then oxo groups at the uranium center by salt elimination, protonolysis, and two‐electron oxidation, respectively. The oxo and imido groups adopt axial positions in a T‐shaped motif with respect to the carbene, which is consistent with an inverse trans‐influence. Complex 5 reacts with tert‐butylisocyanate at the imido rather than carbene group to afford the uranyl(VI) carbene complex [U(BIPMTMS)(O)2(DMAP)2] ( 6 ). 相似文献
6.
Erli Lu Oliver J. Cooper Jonathan McMaster Floriana Tuna Eric J. L. McInnes William Lewis Alexander J. Blake Stephen T. Liddle 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(26):6814-6818
We report the uranium(VI) carbene imido oxo complex [U(BIPMTMS)(NMes)(O)(DMAP)2] ( 5 , BIPMTMS=C(PPh2NSiMe3)2; Mes=2,4,6‐Me3C6H2; DMAP=4‐(dimethylamino)pyridine) which exhibits the unprecedented arrangement of three formal multiply bonded ligands to one metal center where the coordinated heteroatoms derive from different element groups. This complex was prepared by incorporation of carbene, imido, and then oxo groups at the uranium center by salt elimination, protonolysis, and two‐electron oxidation, respectively. The oxo and imido groups adopt axial positions in a T‐shaped motif with respect to the carbene, which is consistent with an inverse trans‐influence. Complex 5 reacts with tert‐butylisocyanate at the imido rather than carbene group to afford the uranyl(VI) carbene complex [U(BIPMTMS)(O)2(DMAP)2] ( 6 ). 相似文献
7.
Jennifer Malberg Thomas Wiegand Prof. Dr. Hellmut Eckert Dr. Michael Bodensteiner Prof. Dr. Robert Wolf 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(7):2356-2369
The synthesis and structural characterization of the first coordination compounds of bis(diphosphacyclobutadiene) cobaltate anions [M(P2C2R2)2]? is described. Reactions of the new potassium salts [K(thf)3{Co(η4‐P2C2tPent2)2}] ( 1 ) and [K(thf)4{Co(η4‐P2C2Ad2)2}] ( 2 ) with [AuCl(tht)] (tht=tetrahydrothiophene), [AuCl(PPh3)] and Ag[SbF6] afforded the complexes [Au{Co(P2C2tPent2)2}(PMe3)2] ( 3 ), [Au{Co(P2C2Ad2)2}]x ( 4 ), [Ag{Co(P2C2Ad2)2}]x ( 5 ), [Au(PMe3)4][Au{Co(P2C2Ad2)2}2] ( 6 ), [K([18]crown‐6)(thf)2][Au{Co(P2C2Ad2)2}2] ( 7 ), and [K([18]crown‐6)(thf)2][M{Co(P2C2Ad2)2}2] ( 8 : M=Au 9 : M=Ag) in moderate yields. The molecular structures of 2 and 3 , and 6 – 9 were elucidated by X‐ray crystallography. Complexes 4 – 9 were thoroughly characterized by 31P and 13C solid state NMR spectroscopy. The complexes [Au{Co(P2C2Ad2)2}]x ( 4 ) and [Ag{Co(P2C2Ad2)2}]x ( 5 ) exist as coordination polymers in the solid state. The linking mode between the monomeric units in the polymers is deduced. The soluble complexes 1 – 3 , 6 , and 7 were studied by multinuclear 1H‐, 31P{1H}‐, and 13C{1H} NMR spectroscopy in solution. Variable temperature NMR measurements of 3 and 6 in deuterated THF reveal the formation of equilibria between the ionic species [Au(PMe3)4]+, [Au(PMe3)2]+, [Co(P2C2R2)2]?, and [Au{Co(P2C2R2)2}2]? (R=tPent and Ad). 相似文献
8.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7681-7686
The trapping of a silicon(I) radical with N‐heterocyclic carbenes is described. The reaction of the cyclic (alkyl)(amino) carbene [cAACMe] (cAACMe=:C(CMe2)2(CH2)NAr, Ar=2,6‐i Pr2C6H3) with H2SiI2 in a 3:1 molar ratio in DME afforded a mixture of the separated ion pair [(cAACMe)2Si:.]+I− ( 1 ), which features a cationic cAAC–silicon(I) radical, and [cAACMe−H]+I−. In addition, the reaction of the NHC–iodosilicon(I) dimer [IAr(I)Si:]2 (IAr=:C{N(Ar)CH}2) with 4 equiv of IMe (:C{N(Me)CMe}2), which proceeded through the formation of a silicon(I) radical intermediate, afforded [(IMe)2SiH]+I− ( 2 ) comprising the first NHC–parent‐silyliumylidene cation. Its further reaction with fluorobenzene afforded the CAr−H bond activation product [1‐F‐2‐IMe‐C6H4]+I− ( 3 ). The isolation of 2 and 3 confirmed the reaction mechanism for the formation of 1 . Compounds 1 – 3 were analyzed by EPR and NMR spectroscopy, DFT calculations, and X‐ray crystallography. 相似文献
9.
Stable ‐ESiMe3 Complexes of CuI and AgI (E=S,Se) with NHCs: Synthons in Ternary Nanocluster Assembly
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Mahmood Azizpoor Fard Tetyana I. Levchenko Carolyn Cadogan William J. Humenny Prof. Dr. John F. Corrigan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(13):4543-4550
As a part of efforts to prepare new “metallachalcogenolate” precursors and develop their chemistry for the formation of ternary mixed‐metal chalcogenide nanoclusters, two sets of thermally stable, N‐heterocyclic carbene metal–chalcogenolate complexes of the general formula [(IPr)Ag?ESiMe3] (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene; E=S, 1 ; Se, 2 ) and [(iPr2‐bimy)Cu?ESiMe3]2 (iPr2‐bimy=1,3‐diisopropylbenzimidazolin‐2‐ylidene; E=S, 4 ; Se, 5 ) are reported. These are prepared from the reaction between the corresponding carbene metal acetate, [(IPr)AgOAc] and [(iPr‐bimy)CuOAc] respectively, and E(SiMe3)2 at low temperature. The reaction of [(IPr)Ag?ESiMe3] 1 with mercury(II) acetate affords the heterometallic complex [{(IPr)AgS}2Hg] 3 containing two (IPr)Ag?S? fragments bonded to a central HgII, representing a mixed mercury–silver sulfide complex. The reaction of [(iPr2‐bimy)Cu‐SSiMe3]2, which contains a smaller N‐heterocyclic‐carbene, with mercuric(II) acetate affords the high nuclearity cluster, [(iPr2‐bimy)6Cu10S8Hg3] 6 . The new N‐heterocyclic carbene metal–chalcogenolate complexes 1 , 2 , 4 , 5 and the ternary mixed‐metal chalcogenolate complex 3 and cluster 6 have been characterized by multinuclear NMR spectroscopy (1H and 13C), elemental analysis and single‐crystal X‐ray diffraction. 相似文献
10.
Novel chiral methylpropargyl esters bearing azobenzene groups, namely, 4‐[4′‐(benzyloxy)phenylazophenyl]‐ carbonyl‐(S)‐1‐methylpropargyl ester ( e ), 4‐[4′‐(n‐butyloxy)phenylazophenyl]carbonyl‐(S)‐1‐methylpropargyl ester ( f ), 4‐[4′‐(n‐hexyloxy)phenylazophenyl]carbonyl‐(S)‐1‐methylpropargyl ester ( g ), and 4‐[4′‐(n‐octyloxy)phenylazo‐ phenyl]carbonyl‐(S)‐1‐methylpropargyl ester ( h ) were synthesized and polymerized with Rh+(nbd)[η6‐C6H5B?‐ (C6H5)3] (nbd=norbornadiene) catalyst to give the corresponding polymers with moderate molecular weights (Mn=8.4×103–15.7×103) in good yields (76%? –?91%). The structures of polymers were illustrated by IR and NMR spectroscopies. Polymers were soluble in comment organic solvents including toluene, CHCl3 CH2Cl2, THF, and DMSO, while insoluble in diethyl ether, n‐hexane and methanol. Large optical rotations of polymer solutions demonstrated that all the polymers take a helical structure with a predominantly one‐handed screw sense in organic solvents. 相似文献
11.
Juraj Kuchr Juraj ernk Khalil A. Abboud 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(10):m492-m494
The title compound, catena‐poly[[μ‐cyano‐1:2κ2C:N‐dicyano‐1κ2C‐bis(N,N‐dimethylethylenediamine‐2κ2N,N′)palladium(II)copper(II)]‐μ‐cyano‐1:2′κ2C:N], [CuPd(CN)4(C4H12N2)2]n, consists of infinite quasi‐linear chains with all metal positions on centers of symmetry. The paramagnetic [Cu(dmen)2]2+ cations are linked by diamagnetic [Pd(CN)4]2− anions via bridging cyano groups, which occupy trans positions in both cation and anion, giving rise to 2,2‐TT‐type chains. The coordination polyhedron of the paramagnetic Cu atom is an octahedron exhibiting typical elongation due to the Jahn–Teller effect, with two longer Cu—N([triple‐bond]C) bonds in the axial positions [2.5528 (13) Å] and four shorter Cu—Ndmen bonds (dmen is N,N‐dimethylethylenediamine) in the equatorial plane [1.9926 (11) and 2.1149 (12) Å]. The Cu—N[triple‐bond]C angle is 138.03 (12)°. Neighboring chains form weak N—H⋯NC hydrogen bonds. 相似文献
12.
The effect of dicationic gemini surfactants H33C16(CH3)2N+‐(CH2)s‐N+(CH3)2 C16H33, 2Br? (s= 4, 5, 6) on the reaction of a dipeptide glycyl–tyrosine (Gly–Tyr) with ninhydrin has been studied spectrophotometrically at 70°C and pH 5.0. The reaction follows first‐ and fractional‐order kinetics, respectively, in [Gly–Tyr] and [ninhydrin]. The gemini surfactant micellar media are comparatively more effective than their single chain–single head counterpart cetyltrimethylammonium bromide (CTAB) micelles. Whereas typical rate constant (kΨ) increase and leveling‐off regions, just like CTAB, are observed with geminis, the latter produces a third region of increasing kΨ at higher concentrations. This subsequent increase is ascribed to the change in the micellar morphology of the geminis. The pseudophase model of micelles was used to quantitatively analyze the kΨ ? [gemini] data, wherein the micellar‐binding constants KS for [Gly–Tyr] and KN for ninhydrin were evaluated. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 800–809, 2012 相似文献
13.
Friedrich Schoder Ulrike Plaia Robert Metzner Wilfried Sperber Wolfgang Beck Wolf Peter Fehlhammer Prof. Dr. 《无机化学与普通化学杂志》2010,636(5):700-709
The reactions of [Re(CO)6]+, [FeCp(CO)2CS]+ and [FeCp(CNPh)3]+ with the metallo nitrile ylides [M–{C+=N–C–(H)CO2Et}(CO)5]– (M = Cr, W) and the chromio nitrile imine [Cr–{C+=N–N–H}(CO)5]– (generated by mono‐α‐deprotonation of the parent isocyanide complexes) to give neutral 5‐metallated 1,3‐oxazolin‐ ( 1 ), 1,3‐thiazolin‐ ( 2 ), imidazolin‐ ( 3 , 4 ), 1,3,4‐oxdiazolin‐ ( 5 ), 1,3,4‐thiadiazolin‐ ( 6 ) and 1,3,4‐triazolin‐2‐ylidene ( 8 ) chromium and tungsten complexes represent the first all‐organometallic versions of Huisgen’s 1,3‐dipolar cycloadditions. The formation of 6 and 8 is accompanied by partial decomposition to (OC)5Cr–C≡N–FeCpL2 {L = CO ( 7 ), CNPh ( 9 )}. The structures of 4a and 5 have been characterized by X‐ray diffraction. 相似文献
14.
Wissam Iali Soumya S. Roy Ben J. Tickner Fadi Ahwal Aneurin J. Kennerley Simon B. Duckett 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(30):10377-10381
Hyperpolarisation methods that premagnetise agents such as pyruvate are currently receiving significant attention because they produce sensitivity gains that allow disease tracking and interrogation of cellular metabolism by magnetic resonance. Here, we communicate how signal amplification by reversible exchange (SABRE) can provide strong 13C pyruvate signal enhancements in seconds through the formation of the novel polarisation transfer catalyst [Ir(H)2(η2‐pyruvate)(DMSO)(IMes)]. By harnessing SABRE, strong signals for [1‐13C]‐ and [2‐13C]pyruvate in addition to a long‐lived singlet state in the [1,2‐13C2] form are readily created; the latter can be observed five minutes after the initial hyperpolarisation step. We also demonstrate how this development may help with future studies of chemical reactivity. 相似文献
15.
Markus Henn Klaus Jurkschat Ralf Ludwig Michael Mehring Katja Peveling Markus Schürmann 《无机化学与普通化学杂志》2002,628(13):2940-2947
The reaction of the organolithium derivative {2, 6‐[P(O)(OEt)2]2‐4‐tert‐Bu‐C6H2}Li ( 1 ‐Li) with [Ph3C]+[PF6]— gave the substituted biphenyl derivative 4‐[(C6H5)2CH]‐4′‐[tert‐Bu]‐2′, 6′‐[P(O)(OEt)2]2‐1, 1′‐biphenyl ( 5 ) which was characterized by 1H, 13C and 31P NMR spectroscopy and single crystal X‐ray analysis. Ab initio MO‐calculations reveal the intramolecular O···C distances in 5 of 2.952(4) and 2.988(5)Å being shorter than the sum of the van der Waals radii of oxygen and carbon to be the result of crystal packing effects. Also reported are the synthesis and structure of the bromine‐substituted derivative {2, 6‐[P(O)(OEt)2]2‐4‐tert‐Bu]C6H2}Br ( 9 ) and the structure of the protonated ligand 5‐tert‐Bu‐1, 3‐[P(O)(OEt)2]2C6H3 ( 1 ‐H). The structures of 1 ‐H, 5 , and 9 are compared with those of related metal‐substituted derivatives. 相似文献
16.
Synthesis and Structure of (N,)C,N‐chelated Organoantimony(III) and Bismuth(III) Cations and Isolation of Their Adducts with Ag[CB11H12]
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Iva Vránová Milan Erben Roman Jambor Aleš Růžička Robert Jirásko Libor Dostál 《无机化学与普通化学杂志》2016,642(21):1212-1217
The treatment of N,C,N‐chelated antimony(III) and bismuth(III) chlorides [C6H3‐2,6‐(CH=NR)2]MCl2 [R = tBu and M = Sb ( 1 ) or Bi ( 2 ); R = Dmp and M = Sb ( 3 ) or Bi ( 4 )] (Dmp = 2,6‐Me2C6H3) with one molar equivalent of Ag[CB11H12] led to a smooth formation of corresponding ionic pairs {[C6H3‐2,6‐(CH=NR)2]MCl}+[CB11H12]– [R = tBu and M = Sb ( 7 ) or Bi ( 8 ), R = Dmp and M = Sb ( 9 ) or Bi ( 10 )]. Similarly, the reaction of C,N‐chelated analogues [C6H2‐2‐(CH=NDip)‐4,6‐(tBu)2]MCl2 [M = Sb ( 5 ) or Bi ( 6 ), Dip = 2′,6′‐iPr2C6H3] gave compounds {[C6H2‐2‐(CH=NDip)‐4,6‐(tBu)2]MCl}+[CB11H12]– [M = Sb ( 11 ) or Bi ( 12 )]. All compounds 7 – 12 were characterized with 1H, 11B and 13C{1H} NMR spectroscopy, ESI‐mass spectrometry, IR spectroscopy, and molecular structures of 7 – 9 and 12 were determined by the help of single‐crystal X‐ray diffraction analysis. In contrast, all attempts to cleave also the second M–Cl bond in 7 – 12 using another molar equivalent Ag[CB11H12] remained unsuccessful. Nevertheless, the reaction between 7 (or 8 ) and Ag[CB11H12] produced unprecedented adducts of both reagents namely {[C6H3‐2,6‐(CH=NtBu)2]SbCl}22+[Ag2(CB11H12)4]2– ( 13 ) and {[C6H3‐2,6‐(CH=NtBu)2]BiCl}+[Ag(CB11H12)2]– ( 14 ) in a reproducible manner. The molecular structures of these sparingly soluble compounds were determined by single‐crystal X‐ray diffraction analysis. 相似文献
17.
Synthesis,Structure, and Fluxionality of Strained Hypercoordinate Silicon‐Bridged [1]Ferrocenophanes
《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(13):3042-3054
The first hypercoordinate sila[1]ferrocenophanes [fcSiMe(2‐C6H4CH2NMe2)] ( 5 a ) and [fcSi(CH2Cl)(2‐C6H4CH2NMe2)] ( 5 b ) (fc=(η5‐C5H4)Fe(η5‐C5H4)) were synthesized by low‐temperature (?78 °C) reactions of Li[2‐C6H4CH2NMe2] with the appropriate chlorinated sila[1]ferrocenophanes ([fcSiMeCl] ( 1 a ) and [fcSi(CH2Cl)Cl] ( 1 d ), respectively). Single‐crystal Xray diffraction studies revealed pseudo‐trigonal bipyramidal structures for both 5 a and 5 b , with one of the shortest reported Si???N distances for an sp3‐hybridized nitrogen atom interacting with a tetraorganosilane detected for 5 a (2.776(2) Å). Elongated Si? Cipso bonds trans to the donating NMe2 arms (1.919(2) and 1.909(2) Å for 5 a and 5 b , respectively) were observed relative to both the non‐trans bonds ( 5 a : 1.891(2); 5 b : 1.879(2) Å) and the Si? Cipso bonds of the non‐hypercoordinate analogues ([fcSiMePh] ( 1 b ): 1.879(4), 1.880(4) Å; [fcSi(CH2Cl)Ph] ( 1 e ): 1.881(2), 1.884(2)). Solution‐state fluxionality of 5 a and 5 b , suggestive of reversible coordination of the NMe2 group to silicon, was demonstrated by means of variable‐temperature NMR studies. The ΔG≠ of the fluxional processes for 5 a and 5 b in CD2Cl2 were estimated to be 35.0 and 37.6 kJ mol?1, respectively (35.8 and 38.3 kJ mol?1 in [D8]toluene). The quaternization of 5 a and 5 b by MeOTf, to give [fcSiMe(2‐C6H4CH2NMe3)][OTf] ( 7 a‐ OTf) and [fcSi(CH2Cl)(2‐C6H4CH2NMe3)][OTf] ( 7 b‐ OTf), respectively, supported the reversibility of NMe2 coordination at the silicon center as the source of fluxionality for 5 a and 5 b . Surprisingly, low room‐temperature stability was detected for 5 b due to its tendency to intramolecularly cyclize and form the spirocyclic [fcSi(cyclo‐CH2NMe2CH2C6H4)]Cl ( 9 ‐Cl). This process was observed in both solution and the solid state, and isolation and Xray characterization of 9 ‐Cl was achieved. The model compound, [Fc2Si(2‐C6H4CH2NMe2)2] ( 8 ), synthesized through reaction of [Fc2SiCl2] with two equivalents of Li[2‐C6H4CH2NMe2] at ?78 °C, showed a lack of hypercoordination in both the solid state and in solution (down to ?80 °C). This suggests that either the reduced steric hindrance around Si or the unique electronics of the strained sila[1]ferrocenophanes is necessary for hypercoordination to occur. 相似文献
18.
Ondřej Rudolf Vladimír Mrkvička Antonín Lyčka Michal Rouchal Antonín Klásek 《Helvetica chimica acta》2012,95(8):1352-1372
The Riemschneider reaction of 3‐thiocyanatoquinoline‐2,4(1H,3H)‐diones with conc. H2SO4 was investigated. Using different reaction conditions, 13 types of reaction products were isolated. Compounds bearing a Me, Et, or Bu group at C(3) afforded mainly [1,3]thiazolo[5,4‐c]quinoline‐2,4‐diones and 1,9b‐dihydro‐9b‐hydroxythiazolo[5,4‐c]quinoline‐2,4‐diones. In the case of the 3‐Bu derivatives of the starting compounds, C‐debutylation was also observed. If a Bn group is present at C(3), rapid C‐debenzylation of the starting thiocyanates occurred, yielding [1,3]oxathiolo[4,5‐c]quinoline‐2,4‐diones, and mixtures of mono‐, di‐, and trisulfides derived from 4‐hydroxy‐3‐sulfanylquinoline‐2‐ones. The reaction mechanism of all of the transformations is discussed. All new compounds were characterized by IR, 1H‐ and 13C‐NMR, and EI and ESI mass spectra, and in some cases, 15N‐NMR spectra were also used to characterize new compounds. 相似文献
19.
Yu‐Liang Shan Dr. Wai‐Leung Yim Dr. Cheuk‐Wai So 《Angewandte Chemie (International ed. in English)》2014,53(48):13155-13158
The synthesis of an N‐heterocyclic silylene‐stabilized digermanium(0) complex is described. The reaction of the amidinate‐stabilized silicon(II) amide [LSiN(SiMe3)2] ( 1 ; L=PhC(NtBu)2) with GeCl2?dioxane in toluene afforded the SiII–GeII adduct [L{(Me3Si)2N}Si→GeCl2] ( 2 ). Reaction of the adduct with two equivalents of KC8 in toluene at room temperature afforded the N‐heterocyclic carbene silylene‐stabilized digermanium(0) complex [L{(Me3Si)2N}Si→ Ge?Ge←Si{N(SiMe3)2}L] ( 3 ). X‐ray crystallography and theoretical studies show conclusively that the N‐heterocyclic silylenes stabilize the singlet digermanium(0) moiety by a weak synergic donor–acceptor interaction. 相似文献
20.
Tobias Rüffer Clemens Bruhn Eduard Rusanov Karsten Nordhoff Dirk Steinborn 《无机化学与普通化学杂志》2002,628(2):421-427
Sulfur‐substituted methylmercury compounds [Hg(CH2SR)2]( 1a, R = Me; 1b, R = Ph ) react with aluminium amalgam in refluxing toluene with transmetallation to give homoleptic tris(thiomethyl)aluminium complexes [Al(CH2SR)3]( 2a, R = Me; 2b, R = Ph ) (degree of conversion: >80%, isolated yields: 2a 63%, 2b 41%). Their identities were confirmed by NMR spectros‐copy (1H, 13C) and X‐ray crystal structure analyses. In crystals of compound 2a the aluminium atoms possess a trigonal‐bipyramidal arrangement with the coordination polyhedron defined by three carbon and two sulfur atoms. Two of the three CH2SMe ligands are bridging ligands (μ‐η2; 1kC:2kS), the third one is terminal bound (η1; kC). The structure is polymeric. Crystals are threaded by helical chains built up of six‐membered Al2C2S2 rings. Crystals of 2b are built up of centrosymmetrical dimers with six‐membered Al2C2S2 rings having bridging CH2SPh ligands (μ‐η2; 1kC:2kS). On each Al atom two terminal (η1; kC)CH2SPh ligands are bound. They exhibit quite different Al‐C‐S angles (116.7(4) and 106.5(3)?). Similar values (114.32115.7? and 109.52109.9?) were found in ab initio calculations of model compounds [{Al(CH2SR)3}2]( 3a, R=H; 3b, R=Me; 3c, R=CH=CH2 ). A conformational energy diagram for rotation of one of the terminal CH2SH ligand in the parent compound 3a around the Al‐C bond is discussed in terms of repulsive interactions of lone electron pairs of sulfur atoms. 相似文献