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1.
[K{Al(NONDipp)}]2 (NONDipp=[O(SiMe2NDipp)2]2?, Dipp=2,6‐iPr2C6H3) reacts with CS2 to afford the trithiocarbonate species [K(OEt2)][Al(NONDipp)(CS3)] 1 or the ethenetetrathiolate complex, [K{Al(NONDipp)(S2C)}]2 [ 3 ]2. The dimeric alumoxane [K{Al(NONDipp)(O)}]2 reacts with carbon monoxide to afford the oxygen analogue of 3 , [K{Al(NONDipp)(O2C)}]2 [ 4 ]2 containing the hitherto unknown ethenetetraolate ligand, [C2O4]4?.  相似文献   

2.
[K{Al(NONDipp)}]2 (NONDipp=[O(SiMe2NDipp)2]2−, Dipp=2,6-iPr2C6H3) reacts with CS2 to afford the trithiocarbonate species [K(OEt2)][Al(NONDipp)(CS3)] 1 or the ethenetetrathiolate complex, [K{Al(NONDipp)(S2C)}]2 [ 3 ]2. The dimeric alumoxane [K{Al(NONDipp)(O)}]2 reacts with carbon monoxide to afford the oxygen analogue of 3 , [K{Al(NONDipp)(O2C)}]2 [ 4 ]2 containing the hitherto unknown ethenetetraolate ligand, [C2O4]4−.  相似文献   

3.
The deoxygenative conversion of carbon dioxide to carbon monoxide is promoted by the aluminyl anion [Al(NONAr)]? (NONAr=[O(SiMe2NAr)2]2?, Ar=2,6‐iPr2C6H3). The reaction proceeds via the isolable monoalumoxane anion [Al(NONAr)(O)]?, containing a terminal aluminum‐oxygen bond. This species reacts with a second equivalent of carbon dioxide to afford the carbonate [Al(NONAr)(CO3)]?, and with nitrous oxide to generate the hyponitrite anion, [Al(NONAr)(κ2O,O′‐N2O2)]?.  相似文献   

4.
Gallia–alumina (Ga,Al)2O3(x : y) spinel-type solid solution nanoparticle catalysts for propane dehydrogenation (PDH) were prepared with four nominal Ga : Al atomic ratios (1 : 6, 1 : 3, 3 : 1, 1 : 0) using a colloidal synthesis approach. The structure, coordination environment and distribution of Ga and Al sites in these materials were investigated by X-ray diffraction, X-ray absorption spectroscopy (Ga K-edge) as well as 27Al and 71Ga solid state nuclear magnetic resonance. The surface acidity (Lewis or Brønsted) was probed using infrared spectroscopy with pyridine and 2,6-dimethylpyridine probe molecules, complemented by element-specific insights (Ga or Al) from dynamic nuclear polarization surface enhanced cross-polarization magic angle spinning 15N{27Al} and 15N{71Ga} J coupling mediated heteronuclear multiple quantum correlation NMR experiments using 15N-labelled pyridine as a probe molecule. The latter approach provides unique insights into the nature and relative strength of the surface acid sites as it allows to distinguish contributions from Al and Ga sites to the overall surface acidity of mixed (Ga,Al)2O3 oxides. Notably, we demonstrate that (Ga,Al)2O3 catalysts with a high Al content show a greater relative abundance of four-coordinated Ga sites and a greater relative fraction of weak/medium Ga-based surface Lewis acid sites, which correlates with superior propene selectivity, Ga-based activity, and stability in PDH (due to lower coking). In contrast, (Ga,Al)2O3 catalysts with a lower Al content feature a higher fraction of six-coordinated Ga sites, as well as more abundant Ga-based strong surface Lewis acid sites, which deactivate through coking. Overall, the results show that the relative abundance and strength of Ga-based surface Lewis acid sites can be tuned by optimizing the bulk Ga : Al atomic ratio, thus providing an effective measure for a rational control of the catalyst performance.

Coordination geometry and Lewis acidity of Ga and Al (bulk and surface) sites in mixed oxide gallia–alumina nanoparticles is correlated with the performance in propane dehydrogenation.  相似文献   

5.
The functionalization of pentaphosphaferrocene [Cp*Fe(η5-P5)] (1) with cationic group 13–17 electrophiles is shown to be a general synthetic strategy towards P–E bond formation of unprecedented diversity. The products of these reactions are dinuclear [{Cp*Fe}2{μ,η5:5-(P5)2EX2}][TEF] (EX2 = BBr2 (2), GaI2 (3), [TEF] = [Al{OC(CF3)3}4]) or mononuclear [Cp*Fe(η5-P5E)][X] (E = CH2Ph (4), CHPh2 (5), SiHPh2 (6), AsCy2 (7), SePh (9), TeMes (10), Cl (11), Br (12), I (13)) complexes of hetero-bis-pentaphosphole ((cyclo-P5)2R) or hetero-pentaphosphole ligands (cyclo-P5R), the aromatic all-phosphorus analogs of prototypical cyclopentadienes. Further, modifying the steric and electronic properties of the electrophile has a drastic impact on its reactivity and leads to the formation of [Cp*Fe(μ,η5:2-P5)SbICp′′′][TEF] (8) which possesses a triple-decker-like structure. X-ray crystallographic characterization reveals the slightly twisted conformation of the cyclo-P5R ligands in these compounds and multinuclear NMR spectroscopy confirms their integrity in solution. DFT calculations shed light on the bonding situation of these compounds and confirm the aromatic character of the pentaphosphole ligands on a journey across the p-block.

The reactivity of cationic electrophiles towards pentaphosphaferrocene [Cp*Fe(ƞ5-P5)] is explored. We report P–E bond formation for electrophiles across the p-block, producing coordination complexes with unprecedented hetero-bispentaphosphole and hetero-pentaphosphole ligands.  相似文献   

6.
For getting an insight into the mechanism of atmospheric autoxidation of sulfur(IV), the kinetics of this autoxidation reaction catalyzed by CoO, Co2O3 and Ni2O3 in buffered alkaline medium has been studied, and found to be defined by Eqs. I and II for catalysis by cobalt oxides and Ni2O3, respectively.
(I)
(II)
The values of empirical rate parameters were: A{0.22(CoO), 0.8 L mol−1s−1 (Co2O3)}, K 1{2.5 × 102 (Ni2O3)}, K 2{2.5 × 102(CoO), 0.6 × 102 (Co2O3)} and k 1{5.0 × 10−2(Ni2O3), 1.0 × 10−6(CoO), 1.7 × 10−5 s−1(Co2O3)} at pH 8.20 (CoO and Co2O3) and pH 7.05 (Ni2O3) and 30 °C. This is perhaps the first study in which the detailed kinetics in the presence of ethanol, a well known free radical scavenger for oxysulfur radicals, has been carried out, and the rate laws for catalysis by cobalt oxides and Ni2O3 in the presence of ethanol were Eqs. III and IV, respectively.
(III)
(IV)
For comparison, the effect of ethanol on these catalytic reactions was studied in acidic medium also. In addition, alkaline medium, the values of the inhibition factor C were 1.9 × 104 and 4.0 × 10L mol−1 s for CoO and Co2O3, respectively; for Ni2O3, C was only 3.0 × 102 only. On the other hand, in acidic medium, the values of this factor were all low: 20 (CoO), 0.7 (Co2O3) and 1.4 (Ni2O3). Based on these results, a radical mechanism for CoO and Co2O3 catalysis in alkaline medium, and a nonradical mechanism for Ni2O3 in both alkaline and acidic media and for cobalt oxides in acidic media are proposed.  相似文献   

7.
A series of new [NiX(S2P{O-c-Hex}2)(PPh3)](X = Cl, Br, I and NCS)(1)–(4) and [Ni(NCS)(S2P{OR}2)(PPh3)][R =n-Pr (5), i-Pr (6)] complexes has been synthesized and characterized by elemental analyses, f.i.r., i.r., u.v.–vis., 1H-, 13C{1H}- and 31P{1H}-n.m.r. spectra, magnetochemical and conductivity measurements. A single crystal X-ray analysis of [Ni(NCS)(S2P{O-n-Pr}2)(PPh3)](5) reveals the molecular structure of the complex and confirms a square-planar geometry around the central atom of nickel with the NCS anion coordinated via the nitrogen atom.  相似文献   

8.
The first X‐ray single‐crystal structure of a {FeNO}8 porphyrin complex [Co(Cp)2][Fe(TFPPBr8)(NO)], and the structure of the {FeNO}7 precursor [Fe(TFPPBr8)(NO)] are determined at 100 K. The two complexes are also characterized by FTIR and UV/Vis spectroscopy. [Fe(TFPPBr8)(NO)]? shows distinct structural features in contrast to a nitrosyl iron(II) porphyrinate on the Fe? N? O? moiety, which include a much more bent Fe? N? O? angle (122.4(3)°), considerably longer Fe? NO? (1.814(4)) and N? O? (1.194(5) Å) bond distances. These and the about 180 cm?1 downshift νN‐O stretch (1540 cm?1) can be understood by the covalently bonding nature between the iron(II) and the NO? ligand which possesses a two‐electron‐occupied π* orbital as a result of the reduction. The overall structural features of [Fe(TFPPBr8)(NO)]? and [Fe(TFPPBr8)(NO)] suggest a low‐spin state of the iron(II) atom at 100 K.  相似文献   

9.
Treatment of the side-on tungsten alkyne complex of ethinylethyl ether [Tp*W(CO)22-C,C′-HCCOCH2CH3)]+ {Tp* = hydridotris(3,4,5-trimethylpyrazolyl)borate} (2a) with n-Bu4NI afforded the end-on ketenyl complex [Tp*W(CO)21-HCCO)] (4a). This formal 16 ve complex bearing the prototype of a ketenyl ligand is surprisingly stable and converts only under activation by UV light or heat to form a dinuclear complex [Tp*2W2(CO)4(μ-CCH2)] (6). The ketenyl ligand in complex 4a underwent a metal template controlled cyclization reaction upon addition of isocyanides. The oxametallacycles [Tp*W(CO)22-C,O-C(NHXy)C(H)C(Nu)O}] {Nu = OMe (7), OEt (8), N(i-Pr)2 (9), OH (10), O1/2 (11)} were formed by coordination of Xy-NC (Xy = 2,6-dimethylphenyl) at 4a and subsequent migratory insertion (MI) into the W-ketenyl bond. The resulting intermediate is susceptible to addition reactions with protic nucleophiles. Compounds 2a-PF6, 4a/b, and 7–11 were fully characterized including XRD analysis. The cyclization mechanism has been confirmed both experimentally and by DFT calculations. In cyclic voltammetry, complexes 7–9 are characterized by a reversible W(ii)/W(iii) redox process. The dinuclear complex 11 however shows two separated redox events. Based on cyclic voltammetry measurements with different conducting electrolytes and IR spectroelectrochemical (SEC) measurements the W(ii)/W(iii) mixed valent complex 11+ is assigned to class II in terms of the Robin-Day classification.

The prototype ketenyl ligand is bound end-on despite a formal 16 valence electron count at the metal. This situation opens a reaction pathway for a multicomponent cyclization centred on the migration of the ketenyl ligand.  相似文献   

10.
Reduction of the indate complex In(NONAr)(μ‐Cl)2Li(OEt2)2 (NONAr=[O(SiMe2NAr)2]2?; Ar=2,6‐iPr2C6H3) with sodium generates the InII diindane species [In(NONAr)]2. Further reduction with a mixture of potassium and [2.2.2]crypt affords the InI N‐heterocyclic indyl anion [In(NONAr)]?, which crystallizes with a non‐contacted [K([2.2.2]crypt)]+ cation. The indyl anion can also be isolated as the indyllithium compound In(NONAr)(Li{THF}3), which contains an In?Li bond. Density functional theory calculations show that the HOMO of the indyl anion is a metal‐centred lone pair, and preliminary reactivity studies confirm its nucleophilic behaviour.  相似文献   

11.
This work reports on the preparation of the complexes [PdCl2(Y1)2], [PdCl2(Y2)2] (Y1 = (p-tolyl)3PCHCOCH3 (1a); Y2 = Ph3PCHCO2CH2Ph (1b)), [Pd{CHP(C7H6)(p-tolyl)2COCH3}(μ-Cl)]2 (2a), [Pd{CHP(C6H4)Ph2CO2CH2Ph}(μ-Cl)]2 (2b), [Pd{CH{P(C7H6)(p-tolyl)2}COCH3}Cl(L)] (L = PPh3 (3a), P(p-tolyl)3 (4a)) and [Pd{CH{P(C6H4)Ph2}CO2CH2Ph}Cl(L)] (L = PPh3 (3b), P(p-tolyl)3 (4b)). Orthometallation and ylide C-coordination in complexes 2a4b are demonstrated by an X-ray diffraction study of 4a.  相似文献   

12.
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive C–H bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,− (L = –N{Dipp}SiMe3); Dipp = 2,6-diisopropyl-phenyl; Mes = (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,−. UV-vis-, EPR-, 57Fe Mössbauer spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic structure as a ferromagnetically coupled iron(ii) imidyl radical, whereas oxidation leads to mixed iron(iii) imidyl and electrophilic iron(ii) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from C–H bonds. Further, the reduced form [Fe(NMes)L2] reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity.

A pair of trigonal imido iron complexes ([Fe(NMes)L2]0,−) in two oxidation states is reported. The anionic complex K{crypt.222}[Fe(NMes)L2] is best described as an iron(ii) imide.  相似文献   

13.
Cathodic materials $ {\hbox{N}}{{\hbox{d}}_{{{2} - x}}}{\hbox{S}}{{\hbox{r}}_x}{\hbox{Fe}}{{\hbox{O}}_{{{4} + \delta }}} $ (x?=?0.5, 0.6, 0.8, 1.0) with K2NiF4-type structure, for use in intermediate-temperature solid oxide fuel cells (IT-SOFCs), have been prepared by the glycine?Cnitrate process and characterized by XRD, SEM, AC impedance spectroscopy, and DC polarization measurements. The results have shown that no reaction occurs between an $ {\hbox{N}}{{\hbox{d}}_{{{2} - x}}}{\hbox{S}}{{\hbox{r}}_x}{\hbox{Fe}}{{\hbox{O}}_{{{4} + \delta }}} $ electrode and an Sm0.2Gd0.8O1.9 electrolyte at 1,200?°C, and that the electrode forms a good contact with the electrolyte after sintering at 1,000?°C for 2?h. In the series $ {\hbox{N}}{{\hbox{d}}_{{{2} - x}}}{\hbox{S}}{{\hbox{r}}_x}{\hbox{Fe}}{{\hbox{O}}_{{{4} + \delta }}} $ (x?=?0.5, 0.6, 0.8, 1.0), the composition $ {\hbox{N}}{{\hbox{d}}_{{{1}.0}}}{\hbox{S}}{{\hbox{r}}_{{{1}.0}}}{\hbox{Fe}}{{\hbox{O}}_{{{4} + \delta }}} $ shows the lowest polarization resistance and cathodic overpotential, 2.75????cm2 at 700?°C and 68?mV at a current density of 24.3?mA?cm?2 at 700?°C, respectively. It has also been found that the electrochemical properties are remarkably improved the increasing Sr content in the experimental range.  相似文献   

14.
The reaction of tBu2P(O)H with Bis2AlH (Bis = CH(SiMe3)2) afforded the adduct tBu2P(H)–O–Al(H)Bis2 (3). It slowly releases H2 to form the first oxygen-bridged geminal Al/P frustrated Lewis pair tBu2P–O–AlBis2. It is capable of reversibly binding molecular hydrogen to afford 3, shown by NMR and H/D scrambling experiments, and forms a 1,2-adduct with CO2. Importantly, the H2 adduct 3 reduces CO2 in a stoichiometric reaction leading to the formic acid adduct tBu2P(H)–O–Al(CO2H)Bis2. The formation of the different species was explored by density functional theory calculations which provide support for the experimental results. All products were characterized by NMR spectroscopy as well as X-ray diffraction experiments and elemental analyses.

Addition vs. reduction: the geminal FLP Bis2Al–O–PtBu2 can reversibly bind molecular hydrogen, it reacts with CO2 to give an adduct, and its hydrogen adduct reduces CO2 to an adduct of formic acid.  相似文献   

15.
We report the synthesis and characterisation of a series of siloxide-functionalised polyoxovanadate–alkoxide (POV–alkoxide) clusters, [V6O6(OSiMe3)(OMe)12]n (n = 1−, 2−), that serve as molecular models for proton and hydrogen-atom uptake in vanadium dioxide, respectively. Installation of a siloxide moiety on the surface of the Lindqvist core was accomplished via addition of trimethylsilyl trifluoromethylsulfonate to the fully-oxygenated cluster [V6O7(OMe)12]2−. Characterisation of [V6O6(OSiMe3)(OMe)12]1− by X-ray photoelectron spectroscopy reveals that the incorporation of the siloxide group does not result in charge separation within the hexavanadate assembly, an observation that contrasts directly with the behavior of clusters bearing substitutional dopants. The reduced assembly, [V6O6(OSiMe3)(OMe)12]2−, provides an isoelectronic model for H-doped VO2, with a vanadium(iii) ion embedded within the cluster core. Notably, structural analysis of [V6O6(OSiMe3)(OMe)12]2− reveals bond perturbations at the siloxide-functionalised vanadium centre that resemble those invoked upon H-atom uptake in VO2 through ab initio calculations. Our results offer atomically precise insight into the local structural and electronic consequences of the installation of hydrogen-atom-like dopants in VO2, and challenge current perspectives of the operative mechanism of electron–proton co-doping in these materials.

We report the synthesis and characterisation of a series of siloxide-functionalised polyoxovanadate–alkoxide clusters, [V6O6(OSiMe3)(OMe)12]n (n = 1, 2), that serve as molecular models for proton and hydrogen-atom uptake in vanadium dioxide.  相似文献   

16.
Hybrid density functional theory calculations on the structures, vibrational frequencies, electron binding and dissociation energies, and bonding properties of CuO$_{3}^{-}$ and CuO3 species have been carried out. Stable isomers containing an O3 subunit and composed of O2 bound to CuO have been located on the potential energy hypersurfaces of CuO$_{3}^{-}$ and CuO3. The isomers formed by O2 bonded to CuO in side‐on and end‐on coordination are more stable than those containing an O3 subunit. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 81: 162–168, 2001  相似文献   

17.
Cooperative dual site activation of boranes by redox-active 1,3-N,S-chelated ruthenium species, mer-[PR32-N,S-(L)}2Ru{κ1-S-(L)}], (mer-2a: R = Cy, mer-2b: R = Ph; L = NC7H4S2), generated from the aerial oxidation of borate complexes, [PR32-N,S-(L)}Ru{κ3-H,S,S′-BH2(L)2}] (transmer-1a: R = Cy, transmer-1b: R = Ph; L = NC7H4S2), has been investigated. Utilizing the rich electronic behaviour of these 1,3-N,S-chelated ruthenium species, we have established that a combination of redox-active ligands and metal–ligand cooperativity has a big influence on the multisite borane activation. For example, treatment of mer-2a–b with BH3·THF led to the isolation of fac-[PR3Ru{κ3-H,S,S′-(NH2BSBH2N)(S2C7H4)2}] (fac-3a: R = Cy and fac-3b: R = Ph) that captured boranes at both sites of the κ2-N,S-chelated ruthenacycles. The core structure of fac-3a and fac-3b consists of two five-membered ruthenacycles [RuBNCS] which are fused by one butterfly moiety [RuB2S]. Analogous fac-3c, [PPh3Ru{κ3-H,S,S′-(NH2BSBH2N)(SC5H4)2}], can also be synthesized from the reaction of BH3·THF with [PPh32-N,S-(SNC5H4)}{κ3-H,S,S′-BH2(SNH4C5)2}Ru], cisfac-1c. In stark contrast, when mer-2b was treated with BH2Mes (Mes = 2,4,6-trimethyl phenyl) it led to the formation of trans- and cis-bis(dihydroborate) complexes [{κ3-S,H,H-(NH2BMes)Ru(S2C7H4)}2], (trans-4 and cis-4). Both the complexes have two five-membered [Ru–(H)2–B–NCS] ruthenacycles with κ2-H–H coordination modes. Density functional theory (DFT) calculations suggest that the activation of boranes across the dual Ru–N site is more facile than the Ru–S one.

Redox-active ruthenium complexes supported by hemilabile κ2-N,S-chelated ruthenacycles undergo unusual dual site B–H bond activation through metal–ligand cooperation with free and bulky boranes.  相似文献   

18.
A reversible carbon–boron bond formation has been observed in the reaction of the coordinatively unsaturated, cyclometalated, Pt(ii) complex [Pt(ItBuiPr′)(ItBuiPr)][BArF], 1, with tricoordinated boranes HBR2. X-ray diffraction studies provided structural snapshots of the sequence of reactions involved in the process. At low temperature, we observed the initial formation of the unprecedented σ-BH complexes [Pt(HBR2)(ItBuiPr′)(ItBuiPr)][BArF], one of which has been isolated. From −15 to +10 °C, the σ-BH species undergo a carbon–boron coupling process leading to the platinum hydride derivative [Pt(H)(ItBuiPr–BR2)(ItBuiPr)][BArF], 4. Surprisingly, these compounds are thermally unstable undergoing carbon–boron bond cleavage at room temperature that results in the 14-electron Pt(ii) boryl species [Pt(BR2)(ItBuiPr)2][BArF], 2. This unusual reaction process has been corroborated by computational methods, which indicate that the carbon–boron coupling products 4 are formed under kinetic control whereas the platinum boryl species 2, arising from competitive C–H bond coupling, are thermodynamically more stable. These findings provide valuable information about the factors governing productive carbon–boron coupling reactions at transition metal centers.

A reversible carbon–boron bond formation has been observed in the reaction of the coordinatively unsaturated, cyclometalated, Pt(ii) complex [Pt(ItBuiPr′)(ItBuiPr)][BArF], 1, with tricoordinated boranes HBR2.  相似文献   

19.
A dinickel(0)–N2 complex, stabilized with a rigid acridane-based PNP pincer ligand, was studied for its ability to activate C(sp2)–H and C(sp2)–O bonds. Stabilized by a Ni–μ–N2–Na+ interaction, it activates C–H bonds of unfunctionalized arenes, affording nickel–aryl and nickel–hydride products. Concomitantly, two sodium cations get reduced to Na(0), which was identified and quantified by several methods. Our experimental results, including product analysis and kinetic measurements, strongly suggest that this C(sp2)–H activation does not follow the typical oxidative addition mechanism occurring at a low-valent single metal centre. Instead, via a bimolecular pathway, two powerfully reducing nickel ions cooperatively activate an arene C–H bond and concomitantly reduce two Lewis acidic alkali metals under ambient conditions. As a novel synthetic protocol, nickel(ii)–aryl species were directly synthesized from nickel(ii) precursors in benzene or toluene with excess Na under ambient conditions. Furthermore, when the dinickel(0)–N2 complex is accessed via reduction of the nickel(ii)–phenyl species, the resulting phenyl anion deprotonates a C–H bond of glyme or 15-crown-5 leading to C–O bond cleavage, which produces vinyl ether. The dinickel(0)–N2 species then cleaves the C(sp2)–O bond of vinyl ether to produce a nickel(ii)–vinyl complex. These results may provide a new strategy for the activation of C–H and C–O bonds mediated by a low valent nickel ion supported by a structurally rigidified ligand scaffold.

A structurally rigidified nickel(0) complex was found to be capable of cleaving both C(sp2)–H and C(sp2)–O bonds.  相似文献   

20.
A stepwise build-up of multi-substituted Csp3 carbon centers is an attractive, conceptually simple, but often synthetically challenging type of disconnection. To this end, this report describes how gem-α,α-dimetalloid-substituted benzylic reagents bearing boron/silicon or boron/tin substituent sets are an excellent stepping stone towards diverse substitution patterns. These gem-dimetalloids were readily accessed, either by known carbenoid insertion into C–B bonds or by the newly developed scalable deprotonation/metallation approach. Highly chemoselective transformations of either the C–Si (or C–Sn) or the C–B bonds in the newly formed gem-Csp3 centers have been achieved through a set of approaches, with a particular focus on exploiting the synthetically versatile polarity reversal in organometalloids by λ3-aryliodanes. Of particular note is the metal-free arylation of the C–Si (or C–Sn) bonds in such gem-dimetalloids via the iodane-guided C–H coupling approach. DFT calculations show that this transfer of the (α-Bpin)benzyl group proceeds via unusual [5,5]-sigmatropic rearrangement and is driven by the high-energy iodine(iii) center. As a complementary tool, the gem-dimetalloid C–B bond is shown to undergo a potent and chemoselective Suzuki–Miyaura arylation with diverse Ar–Cl, thanks to the development of the reactive gem-α,α-silyl/BF3K building blocks.

This work explores divergent reactivity of the benzylic gem-boron–silicon and boron–tin double nucleophiles, including the arylation of the C–B bond with Ar–Cl, along with a complementary oxidative λ3-iodane-guided arylation of the C–Si/Sn moiety.  相似文献   

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