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1.
Marie C. Bayer Christoph Kremser Christoph Jessen Alexander Nitzer Prof. Dr. Andreas J. Kornath 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(15):e202104422
The reaction of fumaryl fluoride with the superacidic solutions XF/MF5 (X=H, D; M=As, Sb) results in the formation of the monoprotonated and diprotonated species, dependent on the stoichiometric ratio of the Lewis acid to fumaryl fluoride. The salts [C4H3F2O2]+[MF6]− (M=As, Sb) and [C4H2X2F2O2]2+([MF6]−)2 (X=H, D; M=As, Sb) are the first examples with a protonated acyl fluoride moiety. They were characterized by low-temperature vibrational spectroscopy. Low-temperature NMR spectroscopy and single-crystal X-ray structure analyses were carried out for [C4H3F2O2]+[SbF6]− as well as for [C4H4F2O2]2+([MF6]−)2 (M=As, Sb). The experimental results are discussed together with quantum chemical calculations of the cations [C4H4F2O2 ⋅ 2 HF]2+ and [C4H3F2O2 ⋅ HF]+ at the B3LYP/aug-cc-pVTZ level of theory. In addition, electrostatic potential (ESP) maps combined with natural population analysis (NPA) charges were calculated in order to investigate the electron distribution and the charge-related properties of the diprotonated species. The C−F bond lengths in the protonated dication are considerably reduced on account of the +R effect. 相似文献
2.
Natalia Tiessen Dr. Nico Schwarze Mira Keßler Beate Neumann Dr. Hans-Georg Stammler Prof. Dr. Berthold Hoge 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(43):11041-11044
While alkyl-substituted siloxanes are widely known, virtually nothing is known about perfluoroalkyl siloxanes and their congener species, the silanols and silanolates. We recently reported on the tris(pentafluoroethyl)silanide ion, [Si(C2F5)3]−, which features Lewis amphoteric character deriving from the pentafluoroethyl substituents and their strong electron-withdrawing properties. Transferring this knowledge, we investigated the Lewis amphoteric behavior of the tris(pentafluoroethyl)silanolate, [Si(C2F5)3O]−. In order to examine such Lewis amphoteric behavior, we first developed a strategy for the synthesis of the corresponding silanol Si(C2F5)3OH, which readily condenses at room temperature to the hexakis(pentafluoroethyl)disiloxane, (C2F5)3SiOSi(C2F5)3. Deprotonation of Si(C2F5)3OH employing a sterically demanding phosphazene base allows the characterization of the first example of a dimeric triorganosilanolate: the dianionic hexakis(pentafluoroethyl)disilanolate, [{Si(C2F5)3O}2]2−, implies Lewis amphoteric character of the monomeric [Si(C2F5)3O]− anion. 相似文献
3.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(12):3323-3327
The metalated ylide YNa [Y=(Ph3PCSO2Tol)−] was employed as X,L‐donor ligand for the preparation of a series of boron cations. Treatment of the bis‐ylide functionalized borane Y2BH with different trityl salts or B(C6F5)3 for hydride abstraction readily results in the formation of the bis‐ylide functionalized boron cation [Y−B−Y]+ ( 2 ). The high donor capacity of the ylide ligands allowed the isolation of the cationic species and its characterization in solution as well as in solid state. DFT calculations demonstrate that the cation is efficiently stabilized through electrostatic effects as well as π‐donation from the ylide ligands, which results in its high stability. Despite the high stability of 2 [Y−B−Y]+ serves as viable source for the preparation of further borenium cations of type Y2B+←LB by addition of Lewis bases such as amines and amides. Primary and secondary amines react to tris(amino)boranes via N−H activation across the B−C bond. 相似文献
4.
Hanieh Roueindeji Antsa Ratsifitahina Dr. Thierry Roisnel Dr. Vincent Dorcet Dr. Samia Kahlal Prof. Dr. Jean-Yves Saillard Prof. Dr. Jean-François Carpentier Dr. Yann Sarazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(37):8854-8864
A set of calcium and barium complexes containing the fluoroarylamide N(C6F5)2− is presented. These compounds illustrate the key role of stabilising M⋅⋅⋅F−C secondary interactions in the construction of low-coordinate alkaline earth complexes. The nature of Ca⋅⋅⋅F−C bonding in calcium complexes is examined in the light of structural data, bond valence sum (BVS) analysis and DFT computations. The molecular structures of [Ca{N(C6F5)2}2(Et2O)2] ( 4 ′), [Ca{μ-N(SiMe3)2}{N(C6F5)2}]2 ( 52 ), [Ba{μ-N(C6F5)2}{N(C6F5)2}⋅toluene]2 ( 62 ), [{BDIDiPP}CaN(C6F5)2]2 ( 72 ), [{N^NDiPP}CaN(C6F5)2]2 ( 82 ), and [Ca{μ-OB(CH(SiMe3)2)2}{N(C6F5)2}]2 ( 92 ), where {BDIDiPP}− and {N^NDiPP}− are the bidentate ligands CH[C(CH3)NDipp]2− and DippNC6H4CNDipp− (Dipp=2,6-iPr2-C6H3), are detailed. Complex 62 displays strong Ba⋅⋅⋅F−C contacts at around 2.85 Å. The calcium complexes feature also very short intramolecular Ca−F interatomic distances at around 2.50 Å. In addition, the three-coordinate complexes 72 and 82 form dinuclear structures due to intermolecular Ca⋅⋅⋅F−C contacts. BVS analysis shows that Ca⋅⋅⋅F−C interactions contribute to 15–20 % of the bonding pattern around calcium. Computations demonstrate that Ca⋅⋅⋅F−C bonding is mostly electrostatic, but also contains a non-negligible covalent contribution. They also suggest that Ca⋅⋅⋅F−C are the strongest amongst the range of weak Ca⋅⋅⋅X (X=F, H, Cπ) secondary interactions, due to the high positive charge of Ca2+ which favours electrostatic interactions. 相似文献
5.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(45):14362-14365
The reactions of the phosphaethynolate anion ([PCO]−) with a range of boranes were explored. BPh3 and [PCO]− form a dimeric anion featuring P−B bonds and is prone to dissociation at room temperature. The more Lewis acidic borane B(C6F5)3 yields a less symmetric dimer of [PCO]− with P−B and P−O bonds. Less sterically demanding HB(C6F5)2 and H2B(C6F5) boranes form a third isomer with [PCO]− featuring both boranes bound to the same phosphorus atom. Despite the unexpected thermodynamic preference for P‐coordination, computational data illustrate that electronic and steric features impact the binding modes of the resulting dianionic dimers. 相似文献
6.
Katharina Thum Alexander Friedrich Jürgen Pahl Holger Elsen Jens Langer Prof. Dr. Sjoerd Harder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(7):2513-2522
The first intermolecular early main group metal–alkene complexes were isolated. This was enabled by using highly Lewis acidic Mg centers in the Lewis base-free cations (MeBDI)Mg+ and (tBuBDI)Mg+ with B(C6F5)4− counterions (MeBDI=CH[C(CH3)N(DIPP)]2, tBuBDI=CH[C(tBu)N(DIPP)]2, DIPP=2,6-diisopropylphenyl). Coordination complexes with various mono- and bis-alkene ligands, typically used in transition metal chemistry, were structurally characterized for 1,3-divinyltetramethyldisiloxane, 1,5-cyclooctadiene, cyclooctene, 1,3,5-cycloheptatriene, 2,3-dimethylbuta-1,3-diene, and 2-ethyl-1-butene. In all cases, asymmetric Mg–alkene bonding with a short and a long Mg−C bond is observed. This asymmetry is most extreme for Mg–(H2C=CEt2) bonding. In bromobenzene solution, the Mg–alkene complexes are either dissociated or in a dissociation equilibrium. A DFT study and AIM analysis showed that the C=C bonds hardly change on coordination and there is very little alkene→Mg electron transfer. The Mg–alkene bonds are mainly electrostatic and should be described as Mg2+ ion-induced dipole interactions. 相似文献
7.
《International journal of quantum chemistry》2018,118(7)
Theoretical studies have been carried out on the halogen bonding interaction between para substituted chlorobenzene (Y C6H4Cl, Y = H, NH2, CH3, F, CN, NO2) and N(CH3)3 using ab initio MP2/aug‐cc‐pVDZ and DFT based wB97XD/6‐311++G(d,p) methods. The positive electrostatic potential (VS,max) on the Cl atom and the heterolytic bond breaking enthalpy of the C Cl bond have been calculated and their role on halogen bonding is discussed. The heterolytic bond breaking enthalpy of the C Cl bond is proposed as a measure of the strength of the σ‐hole on Cl atom. The binding strength of the complexes ranging between −6.13 kJ mol−1 and −9.29 kJ mol−1 are linearly related to the VS,max of the Cl atom and the bond breaking enthalpy of the C Cl bond. In addition, energy decomposition analysis was performed on the halogen bonded complexes via symmetry adapted perturbation theory (SAPT) to predict the dominant energy component and the nature of the N···Cl interaction. 相似文献
8.
Jürgen Pahl Tom E. Stennett Michel Volland Dirk M. Guldi Sjoerd Harder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(8):2025-2034
[(BDI)Mg+][B(C6F5)4−] ( 1 ; BDI=CH[C(CH3)NDipp]2; Dipp=2,6-diisopropylphenyl) was prepared by reaction of (BDI)MgnPr with [Ph3C+][B(C6F5)4−]. Addition of 3-hexyne gave [(BDI)Mg+ ⋅ (EtC≡CEt)][B(C6F5)4−]. Single-crystal X-ray analysis, NMR investigations, Raman spectra, and DFT calculations indicate a significant Mg-alkyne interaction. Addition of the terminal alkynes PhC≡CH or Me3SiC≡CH led to alkyne deprotonation by the BDI ligand to give [(BDI-H)Mg+(C≡CPh)]2 ⋅ 2 [B(C6F5)4−] ( 2 , 70 %) and [(BDI-H)Mg+(C≡CSiMe3)]2 ⋅ 2 [B(C6F5)4−] ( 3 , 63 %). Addition of internal alkynes PhC≡CPh or PhC≡CMe led to [4+2] cycloadditions with the BDI ligand to give {Mg+C(Ph)=C(Ph)C[C(Me)=NDipp]2}2 ⋅ 2 [B(C6F5)4−] ( 4 , 53 %) and {Mg+C(Ph)=C(Me)C[C(Me)=NDipp]2}2 ⋅ 2 [B(C6F5)4−] ( 5 , 73 %), in which the Mg center is N,N,C-chelated. The (BDI)Mg+ cation can be viewed as an intramolecular frustrated Lewis pair (FLP) with a Lewis acidic site (Mg) and a Lewis (or Brønsted) basic site (BDI). Reaction of [(BDI)Mg+][B(C6F5)4−] ( 1 ) with a range of phosphines varying in bulk and donor strength generated [(BDI)Mg+ ⋅ PPh3][B(C6F5)4−] ( 6 ), [(BDI)Mg+ ⋅ PCy3][B(C6F5)4−] ( 7 ), and [(BDI)Mg+ ⋅ PtBu3][B(C6F5)4−] ( 8 ). The bulkier phosphine PMes3 (Mes=mesityl) did not show any interaction. Combinations of [(BDI)Mg+][B(C6F5)4−] and phosphines did not result in addition to the triple bond in 3-hexyne, but during the screening process it was discovered that the cationic magnesium complex catalyzes the hydrophosphination of PhC≡CH with HPPh2, for which an FLP-type mechanism is tentatively proposed. 相似文献
9.
Haopeng Gao Dr. Robert Müller Dr. Elisabeth Irran Dr. Hendrik F. T. Klare Prof. Dr. Martin Kaupp Prof. Dr. Martin Oestreich 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(12):e202104464
Potent main-group Lewis acids are capable of activating element-hydrogen bonds. To probe the rivalry for hydride between silylium- and borenium-ion centers, a neutral precursor with the hydrosilane and hydroborane units in close proximity on a naphthalene-1,8-diyl platform was designed. Abstraction of one hydride leads to a hydroborane-stabilized silylium ion rather than a hydrosilane-coordinated borenium ion paired with [B(C6F5)4]− or [HCB11Cl11]− as counteranions. Characterization by multinuclear NMR spectroscopy and X-ray diffraction supported by DFT calculations reveals a cationic, unsymmetrical open three-center, two-electron (3c2e) Si−H−B linkage. 相似文献
10.
Shanshan Kong Liming Yang Quanchun Sun Tao Wang Runbo Pei Dr. Yue Zhao Prof. Dr. Wenqing Wang Yu Zhao Prof. Dr. Haiyan Cui Prof. Dr. Xinggui Gu Prof. Dr. Xinping Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(19):e202400913
We have synthesized a quinone-incorporated bistriarylamine donor-acceptor-donor (D–A–D) semiconductor 1 by B(C6F5)3 (BCF) catalyzed C−H/C−H cross coupling via radical ion pair intermediates. Coordination of Lewis acids BCF and Al(ORF)3 (RF=C(CF3)3) to the semiconductor 1 afforded diradical zwitterions 2 and 3 by integer electron transfer. Upon binding to Lewis acids, the LUMO energy of 1 is significantly lowered and the band gap of the semiconductor is significantly narrowed from 1.93 eV ( 1 ) to 1.01 eV ( 2 ) and 1.06 eV ( 3 ). 2 and 3 are rare near-infrared (NIR) diradical dyes with broad absorption both centered around 1500 nm. By introducing a photo BCF generator, 2 can be generated by light-dependent control. Furthermore, the integer electron transfer process can also be reversibly regulated via the addition of CH3CN. In addition, the temperature of 2 sharply increased and reached as high as 110 °C in 10 s upon the irradiation of near-infrared-II (NIR-II) laser (1064 nm, 0.7 W cm−2), exhibiting a fast response to laser. It displays excellent photothermal stability with a photothermal (PT) conversion efficiency of 62.26 % and high-quality PT imaging. 相似文献
11.
Dr. Christoph Helling Lars J. C. van der Zee Jelle Hofman Felix J. de Zwart Dr. Simon Mathew Dr. Martin Nieger Assoc. Prof. Dr. J. Chris Slootweg 《Angewandte Chemie (International ed. in English)》2023,62(48):e202313397
Herein, we present the formation of transient radical ion pairs (RIPs) by single-electron transfer (SET) in phosphine−quinone systems and explore their potential for the activation of C−H bonds. PMes3 (Mes=2,4,6-Me3C6H2) reacts with DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone) with formation of the P−O bonded zwitterionic adduct Mes3P−DDQ ( 1 ), while the reaction with the sterically more crowded PTip3 (Tip=2,4,6-iPr3C6H2) afforded C−H bond activation product Tip2P(H)(2-[CMe2(DDQ)]-4,6-iPr2-C6H2) ( 2 ). UV/Vis and EPR spectroscopic studies showed that the latter reaction proceeds via initial SET, forming RIP [PTip3]⋅+[DDQ]⋅−, and subsequent homolytic C−H bond activation, which was supported by DFT calculations. The isolation of analogous products, Tip2P(H)(2-[CMe2{TCQ−B(C6F5)3}]-4,6-iPr2-C6H2) ( 4 , TCQ=tetrachloro-1,4-benzoquinone) and Tip2P(H)(2-[CMe2{oQtBu−B(C6F5)3}]-4,6-iPr2-C6H2) ( 8 , oQtBu=3,5-di-tert-butyl-1,2-benzoquinone), from reactions of PTip3 with Lewis-acid activated quinones, TCQ−B(C6F5)3 and oQtBu−B(C6F5)3, respectively, further supports the proposed radical mechanism. As such, this study presents key mechanistic insights into the homolytic C−H bond activation by the synergistic action of radical ion pairs. 相似文献
12.
Teng-Teng Chen Ling Fung Cheung Wei-Jia Chen Joseph Cavanagh Prof. Dr. Lai-Sheng Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(35):15372-15377
Multiple bonds between boron and transition metals are known in many borylene (:BR) complexes via metal dπ→BR back-donation, despite the electron deficiency of boron. An electron-precise metal–boron triple bond was first observed in BiB2O− [Bi≡B−B≡O]− in which both boron atoms can be viewed as sp-hybridized and the [B−BO]− fragment is isoelectronic to a carbyne (CR). To search for the first electron-precise transition-metal-boron triple-bond species, we have produced IrB2O− and ReB2O− and investigated them by photoelectron spectroscopy and quantum-chemical calculations. The results allow to elucidate the structures and bonding in the two clusters. We find IrB2O− has a closed-shell bent structure (Cs, 1A′) with BO− coordinated to an Ir≡B unit, (−OB)Ir≡B, whereas ReB2O− is linear (C∞v, 3Σ−) with an electron-precise Re≡B triple bond, [Re≡B−B≡O]−. The results suggest the intriguing possibility of synthesizing compounds with electron-precise M≡B triple bonds analogous to classical carbyne systems. 相似文献
13.
Dr. Sonia Bajo Macarena G. Alférez María M. Alcaide Dr. Joaquín López-Serrano Dr. Jesús Campos 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(70):16833-16845
Metal-only Lewis pairs (MOLPs) in which the two metal fragments are solely connected by a dative M→M bond represent privileged architectures to acquire fundamental understanding of bimetallic bonding. This has important implications in many catalytic processes or supramolecular systems that rely on synergistic effects between two metals. However, a systematic experimental/computational approach on a well-defined class of compounds is lacking. Here we report a family of MOLPs constructed around the RhI precursor [(η5-C5Me5)Rh(PMe3)2] ( 1 ) with a series of s, p and d-block metals, mostly from the main group elements, and investigate their bonding by computational means. Among the new MOLPs, we have structurally characterized those formed by dative bonding between 1 and MgMeBr, AlMe3, GeCl2, SnCl2, ZnMe2 and Zn(C6F5)2, as well as spectroscopically identified the ones resulting from coordination to MBArF (M=Na, Li; BArF−=[B(C6H2-3,5-(CF3)2)4]−) and CuCl. Some of these compounds represent unique examples of bimetallic structures, such as the first unambiguous cases of Rh→Mg dative bonding or base-free rhodium bound germylene and stannylene species. Multinuclear NMR spectroscopy, including 103Rh NMR, is used to probe the formation of Rh→M bonds. A comprehensive theoretical analysis of those provides clear trends. As anticipated, greater bond covalency is found for the more electronegative acids, whereas ionic character dominates for the least electronegative nuclei, though some degree of electron sharing is identified in all cases. 相似文献
14.
Philipp Dabringhaus Silja Zedlitz Luisa Giarrana David Scheschkewitz Ingo Krossing 《Angewandte Chemie (International ed. in English)》2023,62(8):e202215170
Schnöckel's [(AlCp*)4] and Jutzi's [SiCp*][B(C6F5)4] (Cp*=C5Me5) are landmarks in modern main-group chemistry with diverse applications in synthesis and catalysis. Despite the isoelectronic relationship between the AlCp* and the [SiCp*]+ fragments, their mutual reactivity is hitherto unknown. Here, we report on their reaction giving the complex salts [Cp*Si(AlCp*)3][WCA] ([WCA]−=[Al(ORF)4]− and [F{Al(ORF)3}2]−; RF=C(CF3)3). The tetrahedral [SiAl3]+ core not only represents a rare example of a low-valent silicon-doped aluminium-cluster, but also—due to its facile accessibility and high stability—provides a convenient preparative entry towards low-valent Si−Al clusters in general. For example, an elusive binuclear [Si2(AlCp*)5]2+ with extremely short Al−Si bonds and a high negative partial charge at the Si atoms was structurally characterised and its bonding situation analysed by DFT. Crystals of the isostructural [Ge2(AlCp*)5]2+ dication were also obtained and represent the first mixed Al−Ge cluster. 相似文献
15.
Youngsuk Kim Dr. Liu Leo Liu Prof. Dr. Douglas W. Stephan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(29):7110-7113
N-Heterocyclic carbene (NHC) derived 3-azabutadienes 1 and 2 have been prepared by a single-step reaction of the corresponding NHC with cyclohexyl isocyanide. Compound 1 features π-basic, delocalized nucleophilic sites over the 3-azabutadiene moiety, therefore allowing for coordinating with small Lewis acids, such as AlCl3, GaCl3, and Me2SAuCl, to form diverse classic Lewis adducts 3 – 5 . Combination of 1 with B(C6F5)3 or [Ph3C][B(C6F5)4] resulted in single-electron transfer and the obtained radical cation was detected by EPR. In addition, a frustrated Lewis pair comprised of the π-basic 1 and BPh3 effects the splitting of the O−H bond of phenol and the N−H bond of imidazole to give 7 and 8 , respectively. An intrinsic bond orbital (IBO) analysis of the pathway leading to 8 showcases the transformation of the delocalized π-electrons of 1 to a newly formed C−H localized σ-bond. 相似文献
16.
Dr. Hélène P. A. Mercier Ulf Breddemann Dr. David S. Brock Mark R. Bortolus Prof. Gary J. Schrobilgen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(52):12105-12119
The noble-gas difluoride adducts, NgF2 ⋅ CrOF4 and NgF2 ⋅ 2CrOF4 (Ng=Kr and Xe), have been synthesized and structurally characterized at low temperatures by Raman spectroscopy and single-crystal X-ray diffraction. The low fluoride ion affinity of CrOF4 renders it incapable of inducing fluoride ion transfer from NgF2 (Ng=Kr and Xe) to form ion-paired salts of the [NgF]+ cations having either the [CrOF5]− or [Cr2O2F9]− anions. The crystal structures show the NgF2 ⋅ CrOF4 adducts are comprised of Ft−Ng−Fb- - -Cr(O)F4 structural units in which NgF2 is weakly coordinated to CrOF4 by means of a fluorine bridge, Fb, in which Ng−Fb is elongated relative to the terminal Ng−Ft bond. In contrast with XeF2 ⋅ 2MOF4 (M=Mo or W) and KrF2 ⋅ 2MoOF4, in which the Lewis acidic, F4(O)M- - -Fb- - -M(O)F3 moiety coordinates to Ng through a single M- - -Fb−Ng bridge, both fluorine ligands of NgF2 coordinate to CrOF4 molecules to form F4(O)Cr- - -Fb−Ng−Fb- - -Cr(O)F4 adducts in which both Ng−Fb bonds are only marginally elongated relative to the Ng−F bonds of free NgF2. Quantum-chemical calculations show that the Cr−Fb bonds of NgF2 ⋅ CrOF4 and NgF2 ⋅ 2CrOF4 are predominantly electrostatic with a small degree of covalent character that accounts for their nonlinear Cr- - -Fb−Ng bridge angles and staggered O−Cr- - -Fb−Ng−Ft dihedral angles. The crystal structures and Raman spectra of two CrOF4 polymorphs have also been obtained. Both are comprised of fluorine-bridged chains that are cis- and trans-fluorine-bridged with respect to oxygen. 相似文献
17.
Dr. Marian Olaru Daniel Duvinage Dr. Enno Lork Dr. Stefan Mebs Prof. Dr. Jens Beckmann 《Angewandte Chemie (International ed. in English)》2018,57(32):10080-10084
Kinetically stabilized congeners of carbenes, R2C, possessing six valence electrons (four bonding electrons and two non‐bonding electrons) have been restricted to Group 14 elements, R2E (E=Si, Ge, Sn, Pb; R=alkyl or aryl) whereas isoelectronic Group 15 cations, divalent species of type [R2E]+ (E=P, As, Sb, Bi; R=alkyl or aryl), were unknown. Herein, we report the first two examples, namely the bismuthenium ion [(2,6‐Mes2C6H3)2Bi][BArF4] ( 1 ; Mes=2,4,6‐Me3C6H2, ArF=3,5‐(CF3)2C6H3) and the stibenium ion [(2,6‐Mes2C6H3)2Sb][B(C6F5)4] ( 2 ), which were obtained by using a combination of bulky meta‐terphenyl substituents and weakly coordinating anions. 相似文献
18.
Salts containing the monoprotonated ethylene carbonate species of were obtained by reacting it with the superacidic systems XF/MF5 (X=H, D; M=Sb, As). The salts in terms of [C3H5O3]+[SbF6]−, [C3H5O3]+[AsF6]− and [C3H4DO3]+[AsF6]− were characterized by low-temperature infrared and Raman spectroscopy. In order to generate the diprotonated species of ethylene carbonate, an excess of Lewis acid was used. However, this only led to the formation of [C3H5O3]+[Sb2F11]−, which was characterized by a single-crystal X-ray structure analysis. Quantum chemical calculations on the B3LYP/aug-cc-PVTZ level of theory were carried out for the [C3H5O3]+ cation and the results were compared with the experimental data. A Natural Bond Orbital (NBO) analysis revealed sp2 hybridization of each atom belonging to the CO3 moiety, thus containing a remarkably delocalized 6π-electron system. The delocalization is confirmed by a 13C NMR-spectroscopic study of [C3H5O3]+[SbF6]−. 相似文献
19.
Henric Steffenfauseweh Dr. Dennis Rottschäfer Dr. Yury V. Vishnevskiy Beate Neumann Dr. Hans-Georg Stammler Dr. Dariusz W. Szczepanik Priv.-Doz. Dr. Rajendra S. Ghadwal 《Angewandte Chemie (International ed. in English)》2023,62(19):e202216003
The first 1,4-distibabenzene-1,4-diide compound [(ADC)Sb]2 ( 5 ) based on an anionic dicarbene (ADC) (ADC=PhC{N(Dipp)C}2, Dipp=2,6-iPr2C6H3) is reported as a bordeaux-red solid. Compound 5 , featuring a central six-membered C4Sb2 ring with formally SbI atoms may be regarded as a base-stabilized cyclic bis-stibinidene in which each of the Sb atoms bears two lone-pairs of electrons. 5 undergoes 2 e-oxidation with Ph3C[B(C6F5)4] to afford [(ADC)Sb]2[B(C6F5)4]2 ( 6 ) as a brick-red solid. Each of the Sb atoms of 6 has an unpaired electron and a lone-pair. The broken-symmetry open-shell singlet diradical solution for ( 6 )2+ is calculated to be 2.13 kcal mol−1 more stable than the closed-shell singlet. The diradical character of ( 6 )2+ according to SS-CASSCF (state-specific complete active space self-consistent field) and UHF (unrestricted Hartree-Fock) methods amounts to 36 % and 39 %, respectively. Treatments of 6 with (PhE)2 yield [(ADC)Sb(EPh)]2[B(C6F5)4]2 ( 7 -E) (E=S or Se). Reaction of 5 with (cod)Mo(CO)4 affords [(ADC)Sb]2Mo(CO)4 ( 8 ). 相似文献
20.
Felix O'Donnell Dr. Douglas Turnbull Prof. Dr. Stacey D. Wetmore Prof. Dr. Michael Gerken 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(66):16334-16337
Antimony pentafluoride is a strong Lewis acid and fluoride-ion acceptor that has not previously demonstrated any discreet fluoride-ion donor properties. The first donor-stabilised [SbF4]+ cations were prepared from the autoionisation of SbF5 in the presence of bidentate N-donor ligands 2,2’-bipyridine (bipy) and 1,10-phenanthroline (phen) as their [SbF6]− salts. The [SbF4(N−N)][Sb2F11] (N−N=bipy, phen) salts were synthesised by the addition of one equivalent of SbF5⋅SO2 to [SbF4(N−N)][SbF6] in liquid SO2. The salts show remarkable stability and were characterised by Raman spectroscopy and multinuclear NMR spectroscopy. The crystal structures of [SbF4(phen)][SbF6] ⋅ 3CH3CN and [SbF4(phen)][SbF6] ⋅ 2SO2 were determined, showing distorted octahedral cations. DFT calculations and NBO analyses reveal that significant degree of electron-pair donation from N to Sb stabilizes [SbF4]+ with the Sb−N bond strength being approximately two thirds of that of the Sb−F bonds in these cations and the cationic charge being primarily ligand-centred. 相似文献