TY - JOUR A1 - Arrowsmith, Merle A1 - Endres, Sara A1 - Heinz, Myron A1 - Nestler, Vincent A1 - Holthausen, Max C. A1 - Braunschweig, Holger T1 - Probing the Boundaries between Lewis-Basic and Redox Behavior of a Parent Borylene JF - Chemistry—A European Journal N2 - The parent borylene (CAAC)(Me\(_{3}\)P)BH, 1 (CAAC=cyclic alkyl(amino)carbene), acts both as a Lewis base and one-electron reducing agent towards group 13 trichlorides (ECl\(_{3}\), E=B, Al, Ga, In), yielding the adducts 1-ECl\(_{3}\) and increasing proportions of the radical cation [1]\(^{•+}\) for the heavier group 13 analogues. With boron trihalides (BX\(_{3}\), X=F, Cl, Br, I) 1 undergoes sequential adduct formation and halide abstraction reactions to yield borylboronium cations and shows an increasing tendency towards redox processes for the heavier halides. Calculations confirm that 1 acts as a strong Lewis base towards EX3 and show a marked increase in the B−E bond dissociation energies down both group 13 and the halide group. KW - redox processes KW - bond dissociation energies KW - borylene KW - group 13 KW - Lewis adducts Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257154 VL - 27 IS - 70 ER - TY - JOUR A1 - Ban, Željka A1 - Karačić, Zrinka A1 - Tomić, Sanja A1 - Amini, Hashem A1 - Marder, Todd B. A1 - Piantanida, Ivo T1 - Triarylborane dyes as a novel non-covalent and non-inhibitive fluorimetric markers for DPP III enzyme JF - Molecules N2 - Novel dyes were prepared by simple “click CuAAC” attachment of a triarylborane–alkyne to the azide side chain of an amino acid yielding triarylborane dye 1 which was conjugated with pyrene (dye 2) forming a triarylborane–pyrene FRET pair. In contrast to previous cationic triarylboranes, the novel neutral dyes interact only with proteins, while their affinity to DNA/RNA is completely abolished. Both the reference triarylborane amino acid and triarylborane–pyrene conjugate bind to BSA and the hDPP III enzyme with high affinities, exhibiting a strong (up to 100-fold) fluorescence increase, whereby the triarylborane–pyrene conjugate additionally retained FRET upon binding to the protein. Furthermore, the triarylborane dyes, upon binding to the hDPP III enzyme, did not impair its enzymatic activity under a wide range of experimental conditions, thus being the first non-covalent fluorimetric markers for hDPP III, also applicable during enzymatic reactions with hDPP III substrates. KW - triarylborane KW - pyrene KW - click CuAAC synthesis KW - DPP III enzyme KW - BSA KW - fluorescence Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-245046 SN - 1420-3049 VL - 26 IS - 16 ER - TY - JOUR A1 - Berger, Sarina M. A1 - Ferger, Matthias A1 - Marder, Todd B. T1 - Synthetic Approaches to Triarylboranes from 1885 to 2020 JF - Chemistry – A European Journal N2 - In recent years, research in the fields of optoelectronics, anion sensors and bioimaging agents have been greatly influenced by novel compounds containing triarylborane motifs. Such compounds possess an empty p‐orbital at boron which results in useful optical and electronic properties. Such a diversity of applications was not expected when the first triarylborane was reported in 1885. Synthetic approaches to triarylboranes underwent various changes over the following century, some of which are still used in the present day, such as the generally applicable routes developed by Krause et al. in 1922, or by Grisdale et al. in 1972 at Eastman Kodak. Some other developments were not pursued further after their initial reports, such as the synthesis of two triarylboranes bearing three different aromatic groups by Mikhailov et al. in 1958. This review summarizes the development of synthetic approaches to triarylboranes from their first report nearly 135 years ago to the present. KW - arylmetalate KW - boranes KW - chromophore KW - Lewis acid KW - synthetic methods Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238952 VL - 27 IS - 24 SP - 7043 EP - 7058 ER - TY - JOUR A1 - Berger, Sarina M. A1 - Rühe, Jessica A1 - Schwarzmann, Johannes A1 - Phillipps, Alexandra A1 - Richard, Ann-Katrin A1 - Ferger, Matthias A1 - Krummenacher, Ivo A1 - Tumir, Lidija-Marija A1 - Ban, Željka A1 - Crnolatac, Ivo A1 - Majhen, Dragomira A1 - Barišić, Ivan A1 - Piantanida, Ivo A1 - Schleier, Domenik A1 - Griesbeck, Stefanie A1 - Friedrich, Alexandra A1 - Braunschweig, Holger A1 - Marder, Todd B. T1 - Bithiophene-Cored, mono-, bis-, and tris-(Trimethylammonium)-Substituted, bis-Triarylborane Chromophores: Effect of the Number and Position of Charges on Cell Imaging and DNA/RNA Sensing JF - Chemistry—A European Journal N2 - The synthesis, photophysical, and electrochemical properties of selectively mono-, bis- and tris-dimethylamino- and trimethylammonium-substituted bis-triarylborane bithiophene chromophores are presented along with the water solubility and singlet oxygen sensitizing efficiency of the cationic compounds Cat\(^{1+}\), Cat\(^{2+}\), Cat(i)\(^{2+}\), and Cat\(^{3+}\). Comparison with the mono-triarylboranes reveals the large influence of the bridging unit on the properties of the bis-triarylboranes, especially those of the cationic compounds. Based on these preliminary investigations, the interactions of Cat\(^{1+}\), Cat\(^{2+}\), Cat(i)\(^{2+}\), and Cat\(^{3+}\) with DNA, RNA, and DNApore were investigated in buffered solutions. The same compounds were investigated for their ability to enter and localize within organelles of human lung carcinoma (A549) and normal lung (WI38) cells showing that not only the number of charges but also their distribution over the chromophore influences interactions and staining properties. KW - singlet oxygen KW - boron KW - bioimaging KW - luminescence KW - nucleic acid Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256963 VL - 27 IS - 56 ER - TY - THES A1 - Brunecker, Carina T1 - Darstellung und Reaktivität dinuklearer Platinphosphankomplexe und Palladium vermittelte Kreuzkupplung zur Synthese von Polyboranen T1 - Synthesis and reactivity of dinuclear platinum phosphine complexes and palladium mediated cross-coupling for the synthesis of polyboranes N2 - Im Rahmen dieser Arbeit war es möglich, diverse dinukleare Platinphosphankomplexe darzustellen, wodurch unteranderem neuartige unsymmetrische (N- Aminoboryl)aminoboryl Pt-Komplexe, Borandiyl- und Diboran-1,2-diyl-verbrückte Diplatin-A-Frame Komplexe synthetisiert und charakterisiert werden konnten. Der abschließende Teil dieser Arbeit befasst sich mit den ersten Versuchen zur Darstellung von Polyboranen durch eine Palladium-vermittelte Kreuzkupplungsreaktion. N2 - Within the scope of this work, it was possible to prepare diverse dinuclear platinum phosphane complexes, allowing, among others, the synthesis and characterization of novel asymmetric (N-aminoboryl)aminoboryl Pt- complexes, boranediyl- and diborane-1,2-diyl-bridged diplatinum A-frame complexes. The final part of this thesis focuses on the first attempts to synthesize polyboranes through a palladium-mediated cross-coupling reaction. KW - Metallorganische Verbindungen KW - Polyborane KW - B-N-Kupplung KW - Kreuzkupplung KW - oxidative Addition KW - Platinkomplexe KW - Kreuzkupplungsreaktion KW - Polyborane KW - A-Frame Komplexe Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-251361 ER - TY - JOUR A1 - Brunecker, Carina A1 - Arrowsmith, Merle A1 - Fantuzzi, Felipe A1 - Braunschweig, Holger T1 - Platin‐vermittelte Kupplung von B=N‐Einheiten: Synthese von BNBN‐Analoga von 1,3‐Dienen und Butatrien JF - Angewandte Chemie N2 - Die 1:2-Reaktion von [μ-(dmpm)Pt(nbe)]\(_{2}\) (dmpm=Bis(dimethylphosphino)methan, nbe=Norbornen) mit Cl\(_{2}\)BNR(SiMe\(_{3}\)) (R=tBu, SiMe\(_{3}\)) führt durch eine B-N-Kupplung über eine ClSiMe\(_{3}\)-Eliminierung zu unsymmetrischen (N-Aminoboryl)aminoboryl-Pt\(^{I}\)\(_{2}\)-Komplexen. Eine anschließende intramolekulare ClSiMe\(_{3}\)-Eliminierung des tBu-Derivats führt zu einer Cyclisierung der BNBN-Einheit unter Bildung eines einzigartigen 1,3,2,4-Diazadiboretidin-2-yl-Liganden. Im Gegensatz hierzu steht die analoge Reaktion mit Br\(_{2}\)BN(SiMe\(_{3}\))\(_{2}\), die über eine zweifache BrSiMe\(_{3}\)-Eliminierung zu einem Pt\(^{II}\)\(_{2}\)-A-Frame-Komplex führt, der von einem linearen Isoster des Butatriens verbrückt wird. Strukturelle und theoretische Daten bestätigen eine π-Elektronen-Delokalisierung über die gesamte BNBN-Einheit. KW - 1,3,2,4-Diazadiboretidin-2-yl-Ligand KW - A-Frame-Komplex KW - B-N-Kupplung KW - Butatrien-Analogon KW - Isosterie Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-244792 VL - 133 IS - 31 SP - 17000 EP - 17004 ER - TY - JOUR A1 - Brückner, Tobias A1 - Fantuzzi, Felipe A1 - Stennett, Tom E. A1 - Krummenacher, Ivo A1 - Dewhurst, Rian D. A1 - Engels, Bernd A1 - Braunschweig, Holger T1 - Isolation of neutral, mono-, and dicationic B\(_2\)P\(_2\) rings by diphosphorus addition to a boron-boron triple bond JF - Angewandte Chemie International Edition N2 - The NHC-stabilised diboryne (B\(_2\)(SIDep)\(_2\); SIDep=1,3-bis(2,6-diethylphenyl)imidazolin-2-ylidene) undergoes a high-yielding P−P bond activation with tetraethyldiphosphine at room temperature to form a B\(_2\)P\(_2\) heterocycle via a diphosphoryldiborene by 1,2-diphosphination. The heterocycle can be oxidised to a radical cation and a dication, respectively, depending on the oxidant used and its counterion. Starting from the planar, neutral 1,3-bis(alkylidene)-1,3-diborata-2,4-diphosphoniocyclobutane, each oxidation step leads to decreased B−B distances and loss of planarity by cationisation. X-ray analyses in conjunction with DFT and CASSCF/NEVPT2 calculations reveal closed-shell singlet, butterfly-shaped structures for the NHC-stabilised dicationic B\(_2\)P\(_2\) rings, with their diradicaloid, planar-ring isomers lying close in energy. KW - inorganic chemistry KW - radicals KW - boron KW - density functional calculations KW - oxidation KW - phosphorus heterocycles Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256451 VL - 60 IS - 24 ER - TY - JOUR A1 - Brückner, Tobias A1 - Heß, Merlin A1 - Stennett, Tom E. A1 - Rempel, Anna A1 - Braunschweig, Holger T1 - Synthesis of Boron Analogues of Enamines via Hydroamination of a Boron-Boron Triple Bond BT - Dedicated to Professor Wolfgang Kaim on the occasion of his 70th birthday JF - Angewandte Chemie, International Edition N2 - An N-heterocyclic-carbene-stabilized diboryne undergoes rapid, high-yielding and catalyst-free hydroamina- tion reactions with primary amines, yielding 1-amino-2-hydro- diborenes, which can be considered boron analogues of enamines. The electronics of the organic substituent at nitrogen influence the structure and further reactivity of the diborene product. With electron-rich anilines, a second hydroamination can occur at the diborene to generate 1,1-diamino-2,2-dihy- drodiboranes. With isopropylamine, the electronic influence of the alkyl substituent upon the diborene leads to an unprece- dented boron-mediated intramolecular N-dearylation reaction of an N-heterocyclic carbene unit. KW - boron KW - diborynes KW - diborenes KW - DFT KW - enamines KW - hydroamination KW - multiple bonds Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240669 VL - 60 IS - 2 ER - TY - THES A1 - Brückner, Tobias Walter T1 - Lewisbasenstabilisierte Bor-Bor-Mehrfachbindungssysteme - Darstellung und Reaktivitätsstudien T1 - Lewis base stabilized boron-boron multiple binding systems - Synthesis and reactivity N2 - Diese Dissertation befasst sich mit der Darstellung und Reaktivität von Lewisbasenstabilisierten Bor-Bor-Mehrfachbindungssystemen. Besonderes Augenmerk lag hierbei auf der Aktivierung von Element-Wasserstoff-Bindungen von Boranen, Aminen, Silanen und Phosphanen durch NHC-stabilisierte Diborine. Des Weiteren wurde die Aktivierung von Bor-Bor-, sowie Phosphor-Phosphor-Einfachbindungen untersucht. Zusätzlich wurde die Reaktivität gegenüber Carbenen und aromatischen Stickstoffbasen näher beleuchtet. N2 - This dissertation deals with the representation and reactivity of Lewis base-stabilized boron-boron multiple bond systems. Special attention was paid to the activation of element-hydrogen bonds of boranes, amines, silanes and phosphanes by NHC-stabilized diborins. Furthermore, the activation of boron-boron and phosphorus-phosphorus single bonds was investigated. In addition, the reactivity towards carbenes and aromatic nitrogen bases was investigated. KW - Diborine KW - Bor KW - boron KW - Diborine KW - Diborene KW - Lewisbasen KW - diborynes KW - diborenes KW - lewis bases KW - Bor KW - Mehrfachbindung KW - Lewis-Base Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213479 ER - TY - JOUR A1 - Budiman, Yudha P. A1 - Lorenzen, Sabine A1 - Liu, Zhiqiang A1 - Radius, Udo A1 - Marder, Todd B. T1 - Base‐Free Pd‐Catalyzed C−Cl Borylation of Fluorinated Aryl Chlorides JF - Chemistry – A European Journal N2 - Catalytic C−X borylation of aryl halides containing two ortho‐fluorines has been found to be challenging, as most previous methods require stoichiometric amounts of base and the polyfluorinated aryl boronates suffer from protodeboronation, which is accelerated by ortho‐fluorine substituents. Herein, we report that a combination of Pd(dba)2 (dba=dibenzylideneacetone) with SPhos (2‐dicyclohexylphosphino‐2’,6’‐dimethoxybiphenyl) as a ligand is efficient to catalyze the C‐Cl borylation of aryl chlorides containing two ortho‐fluorine substituents. This method, conducted under base‐free conditions, is compatible with the resulting di‐ortho‐fluorinated aryl boronate products which are sensitive to base. KW - boronate ester KW - borylation KW - cross-coupling KW - fluoroarene KW - palladium-catalyzed Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225687 VL - 27 IS - 11 SP - 3869 EP - 3874 ER - TY - JOUR A1 - Budiman, Yudha P. A1 - Westcott, Stephen A. A1 - Radius, Udo A1 - Marder, Todd B. T1 - Fluorinated Aryl Boronates as Building Blocks in Organic Synthesis JF - Advanced Synthesis & Catalysis N2 - Organoboron compounds are well known building blocks for many organic reactions. However, under basic conditions, polyfluorinated aryl boronic acid derivatives suffer from instability issues that are accelerated in compounds containing an ortho‐fluorine group, which result in the formation of the corresponding protodeboronation products. Therefore, a considerable amount of research has focused on novel methodologies to synthesize these valuable compounds while avoiding the protodeboronation issue. This review summarizes the latest developments in the synthesis of fluorinated aryl boronic acid derivatives and their applications in cross‐coupling reactions and other transformations. image KW - homogeneous catalysis KW - boron reagents KW - boronates KW - fluorine KW - fluoroarene Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225908 VL - 363 IS - 9 SP - 2224 EP - 2255 ER - TY - JOUR A1 - Chen, Xing A1 - Meng, Guoyun A1 - Liao, Guanming A1 - Rauch, Florian A1 - He, Jiang A1 - Friedrich, Alexandra A1 - Marder, Todd B. A1 - Wang, Nan A1 - Chen, Pangkuan A1 - Wang, Suning A1 - Yin, Xiaodong T1 - Highly Emissive 9-Borafluorene Derivatives: Synthesis, Photophysical Properties and Device Fabrication JF - Chemistry—A European Journal N2 - A series of 9-borafluorene derivatives, functionalised with electron-donating groups, have been prepared. Some of these 9-borafluorene compounds exhibit strong yellowish emission in solution and in the solid state with relatively high quantum yields (up to 73.6 % for FMesB-Cz as a neat film). The results suggest that the highly twisted donor groups suppress charge transfer, but the intrinsic photophysical properties of the 9-borafluorene systems remain. The new compounds showed enhanced stability towards the atmosphere, and exhibited excellent thermal stability, revealing their potential for application in materials science. Organic light-emitting diode (OLED) devices were fabricated with two of the highly emissive compounds, and they exhibited strong yellow-greenish electroluminescence, with a maximum luminance intensity of >22 000 cd m\(^{-2}\). These are the first two examples of 9-borafluorene derivatives being used as light-emitting materials in OLED devices, and they have enabled us to achieve a balance between maintaining their intrinsic properties while improving their stability. KW - boron heterocycles KW - photophysics KW - organic light-emitting diodes KW - luminescence KW - density functional calculations Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256738 VL - 27 IS - 20 ER - TY - THES A1 - Crumbach, Merian T1 - Modifying the Optoelectronic Properties of Polycyclic Aromatic Hydrocarbons and Linear Oligomers by Doping with Boron and Further Heteroatoms T1 - Modifizierung der Optoelektronischen Eigenschaften von Polyzyklischen Aromatischen Kohlenwasserstoffen und Linearen Oligomeren durch Dotierung mit Bor und weiteren Heteroatomen N2 - Der Austausch ausgewählter CC-Einheiten durch ihre isoelektronischen und isosteren BN-Einheiten in π-konjugierten organischen Verbindungen (BN/CC-Isosterie), insbesondere in polyzyklischen aromatischen Kohlenwasserstoffen (PAKs), hat sich als erfolgreiche Strategie zur Herstellung neuartiger organisch-anorganischer Hybridmaterialien erwiesen, die strukturelle Ähnlichkeiten mit ihren reinen Kohlenstoff Analoga aufweisen, aber in vielen Fällen mit veränderten faszinierenden Eigenschaften und Funktionen. In den ersten beiden Kapiteln werden die Synthese und Eigenschaften von neuartigen BNB-dotierten Phenalenylen, Dithienoazadiborepinen und Dithienooxadiborepinen vorgestellt. Die optoelektronischen Eigenschaften dieser neuen Bauelemente können durch Variation der eingebauten Ar- (Mes, Tip, FMes) und R-Gruppen (H, Me, i-Pr, t-Bu, Ph) effektiv eingestellt werden. Theoretische Untersuchungen, einschließlich NICS (Nucleus Independent Chemical Shift) Scans und AICD (Anisotropy of the Induced Current Density)-Berechnungen, wurden durchgeführt und geben Einblick in ihren aromatischen oder antiaromatischen Charakter. Der Einbau von BP-Einheiten, welche mit BN und CC valenz-isoelektronisch sind, in ungesättigte organische Verbindungen ist dagegen bisher kaum untersucht worden, obwohl das Potenzial der resultierenden BCP-Hybridmaterialien für elektronische Anwendungen erst kürzlich erkannt wurde. Konjugierte Hauptkettenpolymere mit BP-Fragmenten im Rückgrat sind bisher unbekannt. Die ersten molekularen Modellverbindungen für ein BP-Analogon des konjugierten Polymers Poly(p-phenylen-vinylen) (PPV) werden in Kapitel 3 vorgestellt. Theoretische Untersuchungen ergaben, dass die Mes*-Gruppe das Phosphor-zentrum vollständig planarisiert, wodurch der B=P-Doppelbindungscharakter verstärkt und eine Konjugation über die BP-Einheit ermöglicht wird. Es wurden verschiedene synthetische Ansätze zu diesen molekularen Modellverbindungen untersucht und eine erfolgreiche synthetische Strategie gefunden. N2 - The substitution of selected CC units by their isoelectronic and isosteric BN units in π−conjugated organic compounds (BN/CC isosterism), especially polycyclic aromatic hydrocarbons (PAHs), has emerged as a viable strategy to produce novel organic–inorganic hybrid materials with structural similarities to their all-carbon congeners, but in many cases with intriguing properties and functions. In the first two chapters the synthesis and properties of novel BNB-doped phenalenyls, dithienoazadiborepins and dithienooxadiborepins are presented. The optoelectronic properties of these new building blocks can be effectively tuned by variation of the incorporated Ar (Mes, Tip, FMes) and R groups (H, Me, i-Pr, t-Bu, Ph). Theoretical investigations, including NICS (Nucleus Independent Chemical Shift) scans and AICD (Anisotropy of the Induced Current Density) calculations, have been performed which provide insight into their aromatic or antiaromatic character, respectively. The incorporation of BP units, on the other hand, which are valence isoelectronic with BN and CC, into unsaturated organic compounds, has been scarcely studied, though the potential of the resulting BCP hybrid materials for electronic applications has been recognized quite recently. Main chain conjugated polymers featuring BP fragments in the backbone are unknown so far. The first molecular model compounds for a BP analogue of the conjugated polymer poly(p-phenylene vinylene) (PPV) are presented in chapter 3. Theoretical investigations revealed that the Mes* group to fully planarizes the phosphorus center, increasing the B=P double bond character and enabling conjugation over the BP unit. Different synthetic approaches to the molecular model compounds have been investigated and a viable synthetic strategy was found. KW - Aromatizität KW - Isoelektronisches Prinzip KW - Polycyclische Aromaten KW - Oligomere KW - Bor KW - BN compounds KW - boron KW - BP compounds KW - polycycles KW - oligomers KW - Bor-Stickstoff-Verbindungen KW - Bor KW - Bor-Phosphor-Verbindungen KW - Polyzyklen KW - Oligomere Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-242845 ER - TY - JOUR A1 - Crumbach, Merian A1 - Bachmann, Jonas A1 - Fritze, Lars A1 - Helbig, Andreas A1 - Krummenacher, Ivo A1 - Braunschweig, Holger A1 - Helten, Holger T1 - Dithiophene‐Fused Oxadiborepins and Azadiborepins: A New Class of Highly Fluorescent Heteroaromatics JF - Angewandte Chemie International Edition N2 - Access to dithiophene‐fused oxadiborepins and the first azadiborepins attained via a modular synthesis route are presented. The new compounds emit intense blue light, some of which demonstrate fluorescence quantum yields close to unity. Cyclic voltammetry (CV) revealed electrochemically reversible one‐electron reduction processes. The weak aromatic character of the novel 1,2,7‐azadiborepin ring is demonstrated with in‐depth theoretical investigations using nucleus‐independent chemical shift (NICS) scans and anisotropy of the induced current density (ACID) calculations. KW - aromaticity KW - BN compounds KW - boron KW - isoelectronic analogues KW - polycycles Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238996 VL - 60 IS - 17 SP - 9290 EP - 9295 ER - TY - JOUR A1 - Cui, Jingjing A1 - Dietz, Maximilian A1 - Härterich, Marcel A1 - Fantuzzi, Felipe A1 - Lu, Wei A1 - Dewhurst, Rian D. A1 - Braunschweig, Holger T1 - Diphosphino-Functionalized 1,8-Naphthyridines: a Multifaceted Ligand Platform for Boranes and Diboranes JF - Chemistry—A European Journal N2 - A 1,8-naphthyridine diphosphine (NDP) reacts with boron-containing Lewis acids to generate complexes featuring a number of different naphthyridine bonding modes. When exposed to diborane B\(_{2}\)Br\(_{4}\), NDP underwent self-deprotonation to afford [NDP-B\(_{2}\)Br\(_{3}\)]Br, an unsymmetrical diborane comprised of four fused rings. The reaction of two equivalents of monoborane BBr\(_{3}\) and NDP in a non-polar solvent provided the simple phosphine-borane adduct [NDP(BBr\(_{3}\))\(_{2}\)], which then underwent intramolecular halide abstraction to furnish the salt [NDP-BBr\(_{2}\)][BBr\(_{4}\)], featuring a different coordination mode from that of [NDP-B\(_{2}\)Br\(_{3}\)]Br. Direct deprotonation of NDP by KHMDS or PhCH2K generates mono- and dipotassium reagents, respectively. The monopotassium reagent reacts with one or half an equivalent of B\(_{2}\)(NMe\(_{2}\))\(_{2}\)Cl\(_{2}\) to afford NDP-based diboranes with three or four amino substituents. KW - pincer ligand KW - potassium reagent KW - diborane KW - naphthyridine KW - boron Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256994 VL - 27 IS - 63 ER - TY - JOUR A1 - Czernetzki, Corinna A1 - Arrowsmith, Merle A1 - Fantuzzi, Felipe A1 - Gärtner, Annalena A1 - Tröster, Tobias A1 - Krummenacher, Ivo A1 - Schorr, Fabian A1 - Braunschweig, Holger T1 - A neutral beryllium(I) radical JF - Angewandte Chemie International Edition N2 - The reduction of a cyclic alkyl(amino)carbene (CAAC)-stabilized organoberyllium chloride yields the first neutral beryllium radical, which was characterized by EPR, IR, UV/Vis spectroscopy and X-ray crystallography. DFT calculations show significant spin density at beryllium and confirm donor–acceptor bonding between an alkylberyllium radical fragment and a neutral CAAC ligand. KW - inorganic chemistry KW - X-ray crystallography KW - Beryllium KW - cyclic alkyl(amino)carbene KW - EDA-NOCV KW - radical Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256529 VL - 60 IS - 38 ER - TY - THES A1 - Duda, Katharina T1 - Synthesen und Eigenschaften von Dicarba-closo-dodecaboran-Derivaten und ersten gemischten Fluorohydridoborat-Anionen T1 - Syntheses and properties of dicarba-closo-dodecaborane derivatives and first mixed fluorohydridoborate anions N2 - Ein wesentliches Ziel dieser Arbeit war die Durchführung von regioselektiven Deborierungsreaktionen von 1,7-Dicarba-closo-dodecaboranen sowie die Herstellung von polyfunktionalisierten meta-Carboran-Derivaten. Die synthetisierten {nido-7,9-C2B9}- und {closo-1,7-C2B10}-Derivate und ausgewählte ortho-Carboran-Derivate wurden nach erfolgter Kumada-artiger Kreuzkupplungsreaktion bzgl. ihrer Koordinationschemie untersucht. Die ethinylfunktionalisierten Borcluster wurden als Edukte für die Herstellung von Gold(I)-Komplexen genutzt. Weitere Ziele dieser Arbeit waren außerdem die Synthese und umfassende Charakterisierung des gemischten Fluorohydridoborat-Anions [BHF3]− und der carboranylsubstituierten Borat-Anionen [1-HF2B-closo-1,2-C2B10H11]− und [1-HF2B-9,12-I2-closo-1,2-C2B10H9]− sowie die Untersuchung hinsichtlich ihrer Folgechemie. N2 - An essential aim of the presented work was the investigation of regioselective deboronation reactions of 1,7-dicarba-closo-dodecaboranes as well as the preparation of poly-functionalized meta-carboranes. After the {nido-7,9-C2B9}-, {closo-1,7-C2B10}- and selected ortho-carborane derivates were prepared by a Kumada-type cross coupling reaction, the behaviour of these compounds in coordination chemistry was examined. The ethynyl-functionalised boron clusters were used as educts for the preparation of gold(I) complexes. Further objectives of this work were the synthesis and complete characterisation of the mixed fluorohydridoborate anion [BHF3]− and of the carboranyl substituted anions [1-HF2B-closo-1,2-C2B10H11]− and [1-HF2B-9,12-I2-closo-1,2-C2B10H9]− and in further applications in syntheses. KW - Carborane KW - Fluoroborate KW - regioselektive Deborierungsreaktionen KW - Gold(I)-Komplexe KW - gemischte Fluorohydridoborat-Anionen KW - Cluster-Aufbau Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181038 ER - TY - JOUR A1 - Ferger, Matthias A1 - Ban, Željka A1 - Krošl, Ivona A1 - Tomić, Sanja A1 - Dietrich, Lena A1 - Lorenzen, Sabine A1 - Rauch, Florian A1 - Sieh, Daniel A1 - Friedrich, Alexandra A1 - Griesbeck, Stefanie A1 - Kenđel, Adriana A1 - Miljanić, Snežana A1 - Piantanida, Ivo A1 - Marder, Todd B. T1 - Bis(phenylethynyl)arene Linkers in Tetracationic Bis-triarylborane Chromophores Control Fluorimetric and Raman Sensing of Various DNAs and RNAs JF - Chemistry-A European Journal N2 - We report four new luminescent tetracationic bis-triarylborane DNA and RNA sensors that show high binding affinities, in several cases even in the nanomolar range. Three of the compounds contain substituted, highly emissive and structurally flexible bis(2,6-dimethylphenyl-4-ethynyl)arene linkers (3: arene=5,5′-2,2′-bithiophene; 4: arene=1,4-benzene; 5: arene=9,10-anthracene) between the two boryl moieties and serve as efficient dual Raman and fluorescence chromophores. The shorter analogue 6 employs 9,10-anthracene as the linker and demonstrates the importance of an adequate linker length with a certain level of flexibility by exhibiting generally lower binding affinities than 3–5. Pronounced aggregation–deaggregation processes are observed in fluorimetric titration experiments with DNA for compounds 3 and 5. Molecular modelling of complexes of 5 with AT-DNA, suggest the minor groove as the dominant binding site for monomeric 5, but demonstrate that dimers of 5 can also be accommodated. Strong SERS responses for 3–5 versus a very weak response for 6, particularly the strong signals from anthracene itself observed for 5 but not for 6, demonstrate the importance of triple bonds for strong Raman activity in molecules of this compound class. The energy of the characteristic stretching vibration of the C≡C bonds is significantly dependent on the aromatic moiety between the triple bonds. The insertion of aromatic moieties between two C≡C bonds thus offers an alternative design for dual Raman and fluorescence chromophores, applicable in multiplex biological Raman imaging. KW - boranes KW - Raman probes KW - molecular modelling KW - fluorescent probes KW - DNA/RNA sensors Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256717 VL - 27 IS - 16 ER - TY - JOUR A1 - Ferger, Matthias A1 - Berger, Sarina M. A1 - Rauch, Florian A1 - Schönitz, Markus A1 - Rühe, Jessica A1 - Krebs, Johannes A1 - Friedrich, Alexandra A1 - Marder, Todd B. T1 - Synthesis of Highly Functionalizable Symmetrically and Unsymmetrically Substituted Triarylboranes from Bench-Stable Boron Precursors JF - Chemistry—A European Journal N2 - A novel and convenient methodology for the one-pot synthesis of sterically congested triarylboranes by using bench-stable aryltrifluoroborates as the boron source is reported. This procedure gives systematic access to symmetrically and unsymmetrically substituted triarylboranes of the types BAr\(_{2}\)Ar’ and BArAr'Ar’’, respectively. Three unsymmetrically substituted triarylboranes as well as their iridium-catalyzed C−H borylation products are reported. These borylated triarylboranes contain one to three positions that can subsequently be orthogonally functionalized in follow-up reactions, such as Suzuki-Miyaura cross-couplings or Sonogashira couplings. KW - synthetic methods KW - boranes KW - borylation KW - chromophore KW - functionalization Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256827 VL - 27 IS - 35 ER - TY - JOUR A1 - Franzsico, Marcos A. S. A1 - Fantuzzi, Felipe A1 - Cardozo, Thiago M. A1 - Esteves, Pierre M. A1 - Engels, Bernd A1 - Oliveira, Ricardo R. T1 - Taming the Antiferromagnetic Beast: Computational Design of Ultrashort Mn-Mn Bonds Stabilized by N-Heterocyclic Carbenes JF - Chemistry—A European Journal N2 - The development of complexes featuring low-valent, multiply bonded metal centers is an exciting field with several potential applications. In this work, we describe the design principles and extensive computational investigation of new organometallic platforms featuring the elusive manganese-manganese bond stabilized by experimentally realized N-heterocyclic carbenes (NHCs). By using DFT computations benchmarked against multireference calculations, as well as MO- and VB-based bonding analyses, we could disentangle the various electronic and structural effects contributing to the thermodynamic and kinetic stability, as well as the experimental feasibility, of the systems. In particular, we explored the nature of the metal-carbene interaction and the role of the ancillary η\(^{6}\) coordination to the generation of Mn\(_{2}\) systems featuring ultrashort metal-metal bonds, closed-shell singlet multiplicities, and positive adiabatic singlet-triplet gaps. Our analysis identifies two distinct classes of viable synthetic targets, whose electrostructural properties are thoroughly investigated. KW - metal-metal interactions KW - ab initio calculations KW - carbene ligands KW - density functional calculations KW - manganese Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256874 VL - 27 IS - 47 ER -