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Dörr J, Alahmadi AF, Henkelmann M, Bolte M, Lerner HW, Wagner M, Jäkle F. Oligomerization of an ansa-ferrocene with pyrazabole bridge. CAN J CHEM 2022. [DOI: 10.1139/cjc-2022-0109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ansa-ferrocenes with pyrazabole bridges are chemically robust entities and therefore suitable building blocks for the synthesis of rigid-rod polymers that combine redox-active Fe(II) centers and beltene-like faces. The specific monomers we developed bear OEt groups at both tetracoordinated boron atoms (for solubility reasons) and ethynyl substituents at the 4-positions of the two pyrazole rings. Polymerization was accomplished by a condensation reaction with 1,4-diiodobenzene using a Sonogashira-Hagihara-type protocol. Thereby, oligomers with a number-average molecular weight of Mn = 7.6 kDa and dispersity of Ð = 1.55 were obtained, suggesting an average chain length of about 14 repeating units based on gel permeation chromatography (GPC) analysis in THF relative to narrow polystyrene standards. The molecular-weight determination was complemented by MALDI-TOF mass spectrometry and (heteronuclear) NMR spectroscopy to verify the intact pyrazabole monomer repeat units and the nature of the end-groups. The oligomers were further characterized by UV−vis spectroscopy and cyclic voltammetry, which demonstrated the successful synthesis of a new class of redox-active materials.
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Rivera A, Ríos-Motta J, Bolte M. First hydrogen-bonded adduct of sterically hindered 2- tert-butyl-4-methylphenol (TBMP) with 1,3,6,8-tetraazatricyclo[4.4.1.1 3,8]dodecane (TATD) via coupling of classical hydrogen bonds and C—H...π non-covalent interactions. Acta Crystallogr E Crystallogr Commun 2022; 78:599-602. [PMID: 36072145 PMCID: PMC9431775 DOI: 10.1107/s2056989022004972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022]
Abstract
Hydrogen bonding links the donor alcohol functional groups of two 2-tert-butyl-4-methylphenol molecules to the central acceptor polyamine aminal cage TATD yielding the three molecule adduct, half of which comprises the asymmetric unit in this crystal structure. The title compound, C8H16N4·2C11H16O, was synthesized from the corresponding sterically crowded phenol by treatment with the aminal cage polyamine. Single-crystal X-ray diffraction structural analysis revealed the three-molecule aggregate to crystallize in the monoclinic space group P2/c with one half of a 1,3,6,8-tetraaztricyclo[4.4.1.13,8]dodecane (TATD) molecule and one 2-tert-butyl-4-methylphenol molecule per asymmetric unit. The crystal structure features intermolecular O—H⋯N and C—H⋯O hydrogen bonds, as well as intermolecular C—H⋯π interactions.
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Goldberg M, Nakajima M, Bolte M, Göbel MW. Facile conversion of 1,2-dicyanobenzene into chiral bisamidines. ARKIVOC 2022. [DOI: 10.24820/ark.5550190.p011.722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Tao J, Bolte M, Lerner HW, Wagner M. Nucleophilic aromatic substitution approach to phosphanyl-substituted diboraanthracenes: biphilic compounds with tunable electron affinities. Org Chem Front 2022. [DOI: 10.1039/d2qo01199a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
9,10-Dimesityl-9,10-dihydro-9,10-diboraanthracenes (Mes2DBAs) bearing one (1), two (2), or four (3) Ph2P-substituents were prepared from Ph2PSiMe3 and tetrafluorinated Mes2DBAs via a nucleophilic aromatic substitution protocol. Using compound 1 as the model...
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Saha S, Kundu S, Biswas PK, Bolte M, Schmittel M. Dynamics of the alkyne → copper( i) interaction and its use in a heteroleptic four-component catalytic rotor. Chem Commun (Camb) 2022; 58:13019-13022. [DOI: 10.1039/d2cc04497h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The dynamics of alkyne → copper(i) interactions has been determined and used to self-assemble a fast nanorotor, which underwent a self-catalyzed click transformation to a triazole rotor, an interesting process for the production of biohybrid devices.
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Henkelmann M, Omlor A, Bolte M, Schünemann V, Lerner HW, Noga J, Hrobárik P, Wagner M. A free boratriptycene-type Lewis superacid. Chem Sci 2022; 13:1608-1617. [PMID: 35282635 PMCID: PMC8826627 DOI: 10.1039/d1sc06404e] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/05/2021] [Indexed: 11/21/2022] Open
Abstract
An exceptionally strong ferrocene-containing, cationic boratriptycene-type Lewis acid is stabilized by a weak Fe⋯B through-space interaction.
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Budy H, Prey SE, Buch CD, Bolte M, Lerner HW, Wagner M. Nucleophilic borylation of fluorobenzenes with reduced arylboranes. Chem Commun (Camb) 2021; 58:254-257. [PMID: 34881754 DOI: 10.1039/d1cc06225e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Two challenging but rewarding topics in chemical synthesis are C-F-bond activation and the development of B-centered nucleophiles. We have now tackled both subjects simultaneously by forming aryl-B bonds via SNAr-type reactions on fluorobenzenes under mild conditions using Na2[FluBBFlu], Li2[HBFlu], and Li2[Me2DBA] (BFlu = 9-borafluorenyl, Me2DBA = 9,10-dimethyl-9,10-dihydro-9,10-diboraanthracene).
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Saeed A, Hökelek T, Bolte M, Erben MF. Intra- and intermolecular N–H•••O=C hydrogen bonds in 1-acyl urea compounds: Synthesis, X-ray structure, conformational and Hirshfeld surface analyses of 1-(2,3-dichlorophenyl)-3-pivaloylurea. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.131271] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kunkel C, Bolte M, Lerner HW, Albert P, Wagner M. Subvalent mixed Si xGe y oligomers: (Cl 3Si) 4Ge and Cl 2(Me 2EtN)SiGe(SiCl 3) 2. Chem Commun (Camb) 2021; 57:12028-12031. [PMID: 34714311 DOI: 10.1039/d1cc05604b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
(Cl3Si)4Ge (1; 91%) is accessible from GeCl4, the Si2Cl6/[nBu4N]Cl silylation system, and excess SiCl4. A key intermediate step involves Cl- sequestration with AlCl3 in the course of the reaction between the first-formed germanide [(Cl3Si)3Ge]- and SiCl4. The related adduct Cl2(Me2EtN)SiGe(SiCl3)2 (2; quantitative conversion) was prepared either by amine-induced cleavage of 1 or by a bottom-up synthesis starting from GeCl4 and Si2Cl6.
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Krieg SC, Grimmer J, Kramer P, Bolte M, Kelm H, Manolikakes G. Oxyenamides as Versatile Building Blocks for a Highly Stereoselective One-Pot Synthesis of the 1,3-Diamino-2-ol-Scaffold Containing Three Continuous Stereocenters. Angew Chem Int Ed Engl 2021; 60:23667-23671. [PMID: 34463410 PMCID: PMC8597051 DOI: 10.1002/anie.202109752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/22/2021] [Indexed: 12/15/2022]
Abstract
A highly diastereoselective one-pot synthesis of the 1,3-diamino-2-alcohol unit bearing three continuous stereocenters is described. This method utilizes 2-oxyenamides as a novel type of building block for the rapid assembly of the 1,3-diamine scaffold containing an additional stereogenic oxygen functionality at the C2 position. A stereoselective preparation of the required (Z)-oxyenamides is reported as well.
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Krieg S, Grimmer J, Kramer P, Bolte M, Kelm H, Manolikakes G. Oxyenamide als vielseitige Bausteine für eine hochgradig stereoselektive Eintopf‐Synthese der 1,3‐Diamino‐2‐ol‐Einheit mit drei fortlaufenden Stereozentren. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Georg I, Bursch M, Endeward B, Bolte M, Lerner HW, Grimme S, Wagner M. The power of trichlorosilylation: isolable trisilylated allyl anions, allyl radicals, and allenyl anions. Chem Sci 2021; 12:12419-12428. [PMID: 34603672 PMCID: PMC8480423 DOI: 10.1039/d1sc03958j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/13/2021] [Indexed: 11/21/2022] Open
Abstract
Treatment of hexachloropropene (Cl2C
Created by potrace 1.16, written by Peter Selinger 2001-2019
]]>
C(Cl)–CCl3) with Si2Cl6 and [nBu4N]Cl (1 : 4 : 1) in CH2Cl2 results in a quantitative conversion to the trisilylated, dichlorinated allyl anion salt [nBu4N][Cl2CC(SiCl3)–C(SiCl3)2] ([nBu4N][1]). Tetrachloroallene Cl2CCCCl2 was identified as the first intermediate of the reaction cascade. In the solid state, [1]− adopts approximate Cs symmetry with a dihedral angle between the planes running through the olefinic and carbanionic fragments of [1]− of CC–Si//Si–C–Si = 78.3(1)°. One-electron oxidation of [nBu4N][1] with SbCl5 furnishes the distillable blue radical 1˙. The neutral propene Cl2CC(SiCl3)–C(SiCl3)2H (2) was obtained by (i) protonation of [1]− with HOSO2CF3 (HOTf) or (ii) H-atom transfer to 1˙ from 1,4-cyclohexadiene. Quantitative transformation of all three SiCl3 substituents in 2 to Si(OMe)3 (2OMe) or SiMe3 (2Me) substituents was achieved by using MeOH/NMe2Et or MeMgBr in CH2Cl2 or THF, respectively. Upon addition of 2 equiv. of tBuLi, 2Me underwent deprotonation with subsequent LiCl elimination, 1,2-SiMe3 migration and Cl/Li exchange to afford the allenyl lithium compound Me3Si(Li)CCC(SiMe3)2 (Li[4]), which is an efficient building block for the introduction of Me, SiMe3, or SnMe3 (5) groups. The trisilylated, monochlorinated allene Cl3Si(Cl)CCC(SiCl3)2 (6), was obtained from [nBu4N][1] through Cl−-ion abstraction with AlCl3 and rearrangement in CH2Cl2 (1˙ forms as a minor side product, likely because the system AlCl3/CH2Cl2 can also act as a one-electron oxidant). Treatment of hexachloropropene (Cl2CC(Cl)–CCl3) with Si2Cl6 and [nBu4N]Cl (1 : 4 : 1) in CH2Cl2 results in a quantitative conversion to the trisilylated, dichlorinated allyl anion salt [nBu4N][Cl2CC(SiCl3)–C(SiCl3)2] ([nBu4N][1]).![]()
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Budy H, Kaese T, Bolte M, Lerner H, Wagner M. A Chemiluminescent Tetraaryl Diborane(4) Tetraanion. Angew Chem Int Ed Engl 2021; 60:19397-19405. [PMID: 34161639 PMCID: PMC8456833 DOI: 10.1002/anie.202106980] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/22/2021] [Indexed: 12/13/2022]
Abstract
Two subvalent, redox-active diborane(4) anions, [3]4- and [3]2- , carrying exceptionally high negative charge densities are reported: Reduction of 9-methoxy-9-borafluorene with Li granules without stirring leads to the crystallization of the B(sp3 )-B(sp2 ) diborane(5) anion salt Li[5]. [5]- contains a 2,2'-biphenyldiyl-bridged B-B core, a chelating 2,2'-biphenyldiyl moiety, and a MeO substituent. Reduction of Li[5] with Na metal gives the Na+ salt of the tetraanion [3]4- in which two doubly reduced 9-borafluorenyl fragments are linked via a B-B single bond. Comproportionation of Li[5] and Na4 [3] quantitatively furnishes the diborane(4) dianion salt Na2 [3], the doubly boron-doped congener of 9,9'-bis(fluorenylidene). Under acid catalysis, Na2 [3] undergoes a formal Stone-Wales rearrangement to yield a dibenzo[g,p]chrysene derivative with B=B core. Na2 [3] shows boron-centered nucleophilicity toward n-butyl chloride. Na4 [3] produces bright blue chemiluminescence when exposed to air.
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Koestler B, Bolte M, Lerner HW, Wagner M. Selective One-Pot Syntheses of Mixed Silicon-Germanium Heteroadamantane Clusters. Chemistry 2021; 27:14401-14404. [PMID: 34387917 PMCID: PMC8596519 DOI: 10.1002/chem.202102732] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Indexed: 11/09/2022]
Abstract
Si x Ge y alloys are emerging materials for modern semiconductor technology. Well-defined model systems of the bulk structures aid in understanding their intrinsic characteristics. Three such model clusters have now been realized in the form of the Si x Ge y heteroadamantanes [0] , [1] , and [2] via selective one-pot syntheses starting from Me 2 GeCl 2 , Si 2 Cl 6 , and [nBu 4 N]Cl. Compound [0] contains 6 GeMe 2 and 4 SiSiCl 3 vertices, while one and two of the GeMe 2 groups are replaced by SiCl 2 moieties in compounds [1] and [2] , respectively. Chloride ion-mediated rearrangement quantitatively converts [2] into [1] at room temperature and finally into [0] at 60 °C, which is not only remarkable in view of the rigidity of these cage structures but also sheds light on the assembly mechanism.
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Bamberg M, Bursch M, Hansen A, Brandl M, Sentis G, Kunze L, Bolte M, Lerner HW, Grimme S, Wagner M. [Cl@Si 20H 20] -: Parent Siladodecahedrane with Endohedral Chloride Ion. J Am Chem Soc 2021; 143:10865-10871. [PMID: 34255517 DOI: 10.1021/jacs.1c05598] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fullerenes and diamondoids are at the core of nanoscience. Comparable monodisperse silicon analogues are scarce. Herein, we report the synthesis of the parent siladodecahedrane, which represents the largest Platonic solid. It shares its pattern of pentagonal faces with the smallest fullerene, C20, and its saturated, H-terminated skeleton with diamondoids. Similar to endofullerenes, the silicon cage encapsulates a chloride ion ([Cl@Si20H20]-); similar to diamondoids, its Si-H termini offer a wealth of opportunities for further functionalization. Mere treatment with chloromethanes leads to the perchlorinated cluster [Cl@Si20Cl20]-. Both compounds were characterized by mass spectrometry, X-ray crystallography, NMR spectroscopy, and quantum-chemical calculations. The experimentally determined 35Cl resonances of the endohedral chloride ions are particularly diagnostic to probe the Cl- → Si20 interaction strength as a function of the different surface substituents, as we have proven by high-level computational analyses.
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Budy H, Kaese T, Bolte M, Lerner H, Wagner M. A Chemiluminescent Tetraaryl Diborane(4) Tetraanion. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106980] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Georg I, Bolte M, Wagner M, Lerner HW. Synthesis and structure of the λ
6Si-silicate [Cs(18-crown-6)] 2[Si(OSO 2CH 3) 6]. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2021. [DOI: 10.1515/znb-2021-0068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The λ
6Si-silicate [Cs(18-crown-6)]2[Si(OSO2CH3)6] (1) was synthesized by treatment of Si2Cl6 with Cs[OSO2CH3] in the presence of 18-crown-6. Compound 1 is the first example of a λ
6Si-silicate with a methanesulfonate ligand. It was characterized by NMR spectroscopy and by single-crystal X-ray diffraction. The solid-state structure of 1 consists of discrete [Si(OSO2CH3)6]2– anions and two [Cs(18-crown-6)]+ cations (triclinic space group,
P
1
¯
$P\overline{1}$
, Z = 1).
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Trageser T, Bebej D, Bolte M, Lerner HW, Wagner M. B-B vs. B-H Bond Activation in a (μ-Hydrido)diborane(4) Anion upon Cycloaddition with CO 2 , Isocyanates, or Carbodiimides. Angew Chem Int Ed Engl 2021; 60:13500-13506. [PMID: 33740318 PMCID: PMC8252796 DOI: 10.1002/anie.202103427] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Indexed: 11/11/2022]
Abstract
The intriguing (μ‐hydrido)diboranes(4) with their prominent pristine representative [B2H5]− have mainly been studied theoretically. We now describe the behavior of the planarized tetraaryl (μ‐hydrido)diborane(4) anion [1H]− in cycloaddition reactions with the homologous series of heterocumulenes CO2, iPrNCO, and iPrNCNiPr. We show that a C=O bond of CO2 selectively activates the B−B bond of [1H]−, while the μ‐H ligand is left untouched ([2H]−). The carbodiimide iPrNCNiPr, in contrast, neglects the B−B bond and rather adds the B‐bonded H− ion to its central C atom to generate a formamidinate bridge across the B2 pair ([3]−). As a hybrid, the isocyanate iPrNCO combines the reactivity patterns of both its congeners and gives two products: one of them ([4H]−) is related to [2H]−, the other ([5]−) is an analog of [3]−. We finally propose a mechanistic scenario that rationalizes the individual reaction outcomes and combines them to a coherent picture of B–B vs. B–H bond activation.
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Trageser T, Bebej D, Bolte M, Lerner H, Wagner M. B–B vs. B–H Bond Activation in a (μ‐Hydrido)diborane(4) Anion upon Cycloaddition with CO
2
, Isocyanates, or Carbodiimides. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103427] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Shiryaev AA, Burkhanova TM, Mitoraj MP, Kukulka M, Sagan F, Mahmoudi G, Babashkina MG, Bolte M, Safin DA. Supramolecular structures of Ni II and Cu II with the sterically demanding Schiff base dyes driven by cooperative action of preagostic and other non-covalent interactions. IUCRJ 2021; 8:351-361. [PMID: 33953922 PMCID: PMC8086159 DOI: 10.1107/s2052252521000610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
This work reports on synthesis and extensive experimental and theoretical investigations on photophysical, structural and thermal properties of the NiII and CuII discrete mononuclear homoleptic complexes [Ni(L I,II)2] and [Cu(L I,II)2] fabricated from the Schiff base dyes o-HOC6H4-CH=N-cyclo-C6H11 (HL I) and o-HOC10H6-CH=N-cyclo-C6H11 (HL II), containing the sterically crowding cyclo-hexyl units. The six-membered metallocycles adopt a clearly defined envelope conformation in [Ni(L II)2], while they are much more planar in the structures of [Ni(L I)2] and [Cu(L I,II)2]. It has been demonstrated by in-depth bonding analyses based on the ETS-NOCV and Interacting Quantum Atoms energy-decomposition schemes that application of the bulky substituents, containing several C-H groups, has led to the formation of a set of classical and unintuitive intra- and inter-molecular interactions. All together they are responsible for the high stability of [Ni(L I,II)2] and [Cu(L I,II)2]. More specifically, London dispersion dominated intramolecular C-H⋯O, C-H⋯N and C-H⋯H-C hydrogen bonds are recognized and, importantly, the attractive, chiefly the Coulomb driven, preagostic (not repulsive anagostic) C-H⋯Ni/Cu interactions have been discovered despite their relatively long distances (∼2.8-3.1 Å). All the complexes are further stabilized by the extremely efficient intermolecular C-H⋯π(benzene) and C-H⋯π(chelate) interactions, where both the charge-delocalization and London dispersion constituents appear to be crucial for the crystal packing of the obtained complexes. All the complexes were found to be photoluminescent in CH2Cl2, with [Cu(L II)2] exhibiting the most pronounced emission - the time-dependent density-functional-theory computations revealed that it is mostly caused by metal-to-ligand charge-transfer transitions.
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Moreno CJ, Hernández K, Charnok SJ, Gittings S, Bolte M, Joglar J, Bujons J, Parella T, Clapés P. Synthesis of γ-Hydroxy-α-amino Acid Derivatives by Enzymatic Tandem Aldol Addition-Transamination Reactions. ACS Catal 2021; 11:4660-4669. [PMID: 34603828 PMCID: PMC8482765 DOI: 10.1021/acscatal.1c00210] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/20/2021] [Indexed: 12/26/2022]
Abstract
![]()
Three
enzymatic routes toward γ-hydroxy-α-amino acids
by tandem aldol addition–transamination one-pot two-step reactions
are reported. The approaches feature an enantioselective aldol addition
of pyruvate to various nonaromatic aldehydes catalyzed by trans-o-hydroxybenzylidene pyruvate hydratase-aldolase
(HBPA) from Pseudomonas putida. This
affords chiral 4-hydroxy-2-oxo acids, which were subsequently enantioselectively
aminated using S-selective transaminases. Three transamination
processes were investigated involving different amine donors and transaminases:
(i) l-Ala as an amine donor with pyruvate recycling, (ii)
a benzylamine donor using benzaldehyde lyase from Pseudomonas
fluorescens Biovar I (BAL) to transform the benzaldehyde
formed into benzoin, minimizing equilibrium limitations, and (iii) l-Glu as an amine donor with a double cascade comprising branched-chain
α-amino acid aminotransferase (BCAT) and aspartate amino transferase
(AspAT), both from E. coli, using l-Asp as a substrate to regenerate l-Glu. The γ-hydroxy-α-amino
acids thus obtained were transformed into chiral α-amino-γ-butyrolactones,
structural motifs found in many biologically active compounds and
valuable intermediates for the synthesis of pharmaceutical agents.
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Tapmeyer L, Eisenbeil D, Bolte M, Schmidt MU. First crystal structure of a Pigment Red 52 compound: DMSO solvate hydrate of the monosodium salt. Acta Crystallogr E Crystallogr Commun 2021; 77:402-405. [PMID: 33936765 PMCID: PMC8025858 DOI: 10.1107/s2056989021002577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/08/2021] [Indexed: 11/10/2022]
Abstract
Pigment Red 52, Na2[C18H11ClN2O6S], is an industrially produced hydrazone-laked pigment. It serves as an inter-mediate in the synthesis of the corresponding Ca2+ and Mn2+ salts, which are used commercially for printing inks and lacquers. Hitherto, no crystal structure of any salt of Pigment Red 52 is known. Now, single crystals have been obtained of a dimethyl sulfoxide solvate hydrate of the monosodium salt of Pigment Red 52, namely, monosodium 2-[2-(3-carb-oxy-2-oxo-1,2-di-hydro-naphthalen-1-yl-idene)hydrazin-1-yl]-5-chloro-4-methyl-benz-ene-sulfonate dimethyl sulfoxide monosolvate monohydrate, Na+·C18H12ClN2O6S-·H2O·C2H6OS, obtained from in-house synthesized Pigment Red 52. The crystal structure was determined by single-crystal X-ray diffraction at 173 K. In this monosodium salt, the SO3 - group is deprotonated, whereas the COOH group is protonated. The residues form chains via ionic inter-actions and hydrogen bonds. The chains are arranged in polar/non-polar double layers.
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Ouadoudi O, Kaehler T, Bolte M, Lerner HW, Wagner M. One tool to bring them all: Au-catalyzed synthesis of B,O- and B,N-doped PAHs from boronic and borinic acids. Chem Sci 2021; 12:5898-5909. [PMID: 34168815 PMCID: PMC8179653 DOI: 10.1039/d1sc00543j] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The isoelectronic replacement of C
Created by potrace 1.16, written by Peter Selinger 2001-2019
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C bonds with −BN+ bonds in polycyclic aromatic hydrocarbons (PAHs) is a widely used tool to prepare novel optoelectronic materials. Far less well explored are corresponding B,O-doped PAHs, although they have a similarly high application potential. We herein report on the modular synthesis of B,N- and B,O-doped PAHs through the [Au(PPh3)NTf2]-catalyzed 6-endo-dig cyclization of BN–H and BO–H bonds across suitably positioned C
Created by potrace 1.16, written by Peter Selinger 2001-2019
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C bonds in the key step. Readily available, easy-to-handle o-alkynylaryl boronic and borinic acids serve as starting materials, which are either cyclized directly or first converted into the corresponding aminoboranes and then cyclized. The reaction even tolerates bulky mesityl substituents on boron, which later kinetically protect the formed B,N/O-PAHs from hydrolysis or oxidation. Our approach is also applicable for the synthesis of rare doubly B,N/O-doped PAHs. Specifically, we prepared 1,2-B,E-naphthalenes and -anthracenes, 1,5-B2-2,6-E2-anthracenes (E = N, O) as well as B,O2-containing and unprecedented B,N,O-containing phenalenyls. Selected examples of these compounds have been structurally characterized by X-ray crystallography; their optoelectronic properties have been studied by cyclic voltammetry, electron spectroscopy, and quantum-chemical calculations. Using a new unsubstituted (B,O)2-perylene as the substrate for late-stage functionalization, we finally show that the introduction of two pinacolatoboryl (Bpin) substituents is possible in high yield and with perfect regioselectivity via an Ir-catalyzed C–H borylation approach. Singly and doubly B,E-doped PAHs were synthesized using a protocol that starts from easy-to-handle boronic and borinic acids and offers the possibility to choose between the preparation of B,O- and B,N-PAHs in the final reaction step.![]()
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Budanow A, Lerner HW, Bolte M. Two salts of the 6,6-difluoro-6 H-dibenzo[ c, e][1,2]oxaborinin-6-ide anion with different cations. Acta Crystallogr E Crystallogr Commun 2020; 76:1837-1840. [PMID: 33520264 PMCID: PMC7784652 DOI: 10.1107/s2056989020015066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 11/12/2020] [Indexed: 11/10/2022]
Abstract
The crystal structures are reported of the 6,6-difluoro-6H-dibenzo[c,e][1,2]oxaborinin-6-ide (or 9,9-difluoro-10-oxa-9-boraphenanthren-9-ide) anion with two different cations, namely, potassium 6,6-difluoro-6H-dibenzo[c,e][1,2]oxaborinin-6-ide, K+·C12H8BF2O−, (II), featuring a polymeric structure, and bis(tetraphenylphosphonium) bis(6,6-difluoro-6H-dibenzo[c,e][1,2]oxaborinin-6-ide) acetonitrile trisolvate, 2C24H20P+·2C12H8BF2O−·3CH3CN, (III), which is composed of discrete cations, anions and acetonitrile solvent molecules linked by C—H...O, C—H...N and C—H...F hydrogen bonds. There are only minor differences in the geometrical parameters of the anions in these structures.
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Hamza A, Sorochkina K, Kótai B, Chernichenko K, Berta D, Bolte M, Nieger M, Repo T, Pápai I. Origin of Stereoselectivity in FLP-Catalyzed Asymmetric Hydrogenation of Imines. ACS Catal 2020. [DOI: 10.1021/acscatal.0c04263] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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