Reactivity of Tetrahalo- and Difluorodiboranes(4) toward Lewis Basic Platinum(0): Bis(boryl), Borylborato, and Doubly Boryl-Bridged Platinum Complexes

Muessig, Jonas H.; Prieschl, Dominic; Deißenberger, Andrea; Dewhurst, Rian D.; Dietz, Maximilian; Jiménez‐Halla, J. Óscar C.; Trumpp, Alexandra; Wang, Sunewang R.; Brunecker, Carina; Haefner, Alena; Gärtner, Annalena; Thiess, Torsten; Böhnke, Julian; Radacki, Krzysztof; Bertermann, Rüdiger; Marder, Todd B.; Braunschweig, Holger

doi:10.1021/jacs.8b08428

Cited by 17 publications

(10 citation statements)

References 89 publications

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“…A comparably large shift difference of 20–24 ppm is observed for B 2 I 4 (SMe 2 ) 2 and B 2 Br 4 (SMe 2 ) 2 ( δ

_{^{11} normalB}

=−20.0 and −0.3 ppm, respectively), as well as B 2 I 4 (PCy 3 ) 2 and B 2 Br 4 (PCy 3 ) 2 ( δ

_{^{11} normalB}

=−28.0 ppm and −4.3 ppm, respectively) . A smaller highfield shift of 5–8 ppm is observed between pairs of B 2 Cl 4 L 2 and B 2 Br 4 L 2 analogues, for example, for B 2 Cl 4 (SMe 2 ) 2 and B 2 Br 4 (SMe 2 ) 2 ( δ

_{^{11} normalB}

=7.3 and −0.3 ppm, respectively), B 2 Cl 4 (PMe 3 ) 2 and B 2 Br 4 (PMe 3 ) 2 ( δ

_{^{11} normalB}

=0.3 and −7.3 ppm, respectively) as well as B 2 Cl 4 (CAAC Me ) 2 and B 2 Br 4 (CAAC Me ) 2 ( δ

_{^{11} normalB}

=2.3 and −2.3 ppm, respectively) . This is in line with the greater increase in relative electronegativity from I to Br (ca.…”

Section: Resultsmentioning

confidence: 90%

Stable Lewis Base Adducts of Tetrahalodiboranes: Synthetic Methods and Structural Diversity

Englert

Stoy

Arrowsmith

et al. 2019

Chemistry A European J

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A series of 22 new bis(phosphine), bis(carbene), and bis(isonitrile) tetrahalodiborane adducts has been synthesized, either by direct adduct formation with highly sensitive B2X4 precursors (X=Cl, Br, I) or by ligand exchange at stable B2X4(SMe2)2 precursors (X=Cl, Br) with labile dimethylsulfide ligands. The isolated compounds have been fully characterized using NMR spectroscopy, elemental analysis, and, for 20 of these compounds, single‐crystal X‐ray diffraction, revealing an unexpected variation in the bonding motifs. In addition to the classical B2X4L2 diborane(4) bis‐adducts, certain more sterically demanding carbene ligands induce a halide displacement which led to the first halide‐bridged monocationic diboron species, [B2X3L2]A (A=BCl4, Br, I). Furthermore, low‐temperature 1:1 reactions of B2Cl4 with sterically demanding N‐heterocyclic carbenes led to the formation of kinetically unstable mono‐adducts, one of which was structurally characterized. A comparison of the NMR spectra and structural data of new and literature‐known bis‐adducts shows several trends pertaining to the nature of the halides and the stereoelectronic properties of the Lewis bases employed.

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“…A comparably large shift difference of 20–24 ppm is observed for B 2 I 4 (SMe 2 ) 2 and B 2 Br 4 (SMe 2 ) 2 ( δ

_{^{11} normalB}

=−20.0 and −0.3 ppm, respectively), as well as B 2 I 4 (PCy 3 ) 2 and B 2 Br 4 (PCy 3 ) 2 ( δ

_{^{11} normalB}

_{^{11} normalB}

=7.3 and −0.3 ppm, respectively), B 2 Cl 4 (PMe 3 ) 2 and B 2 Br 4 (PMe 3 ) 2 ( δ

_{^{11} normalB}

=0.3 and −7.3 ppm, respectively) as well as B 2 Cl 4 (CAAC Me ) 2 and B 2 Br 4 (CAAC Me ) 2 ( δ

_{^{11} normalB}

=2.3 and −2.3 ppm, respectively) . This is in line with the greater increase in relative electronegativity from I to Br (ca.…”

Section: Resultsmentioning

confidence: 90%

Stable Lewis Base Adducts of Tetrahalodiboranes: Synthetic Methods and Structural Diversity

Englert

Stoy

Arrowsmith

et al. 2019

Chemistry A European J

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“…1,1-Di(9-anthryl)-2,2-difluorodiborane(4) ( An 2 BBF 2 ), − , an unsymmetrical diborane(4) that features reactivity patterns often quite divergent from those of its symmetrical relatives, was chosen as another promising substrate for reactions with organic azides. Its reaction with PhN 3 proceeded in a seemingly similar way as that leading to 1 , with a color change from red to orange.…”

Section: Resultsmentioning

confidence: 99%

“…43,44 Reaction of an Unsymmetrical Diborane(4) with Phenyl Azide. 1,1-Di(9-anthryl)-2,2-difluorodiborane(4) (An 2 BBF 2 ), [26][27][28][29]45 an unsymmetrical diborane(4) that Scheme 3. Gibbs Free Energy Profile Calculated for the Reaction of Dur 2 B 2 Br 2 with Phenyl Azide, Leading to the Formation of the Five-Membered Ring Product 1_P (1a) a a The relative Gibbs free energies and electronic energies (in parentheses) are given in kcal mol −1 .…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Synthesis of Complex Boron–Nitrogen Heterocycles Comprising Borylated Triazenes and Tetrazenes Under Mild Conditions

et al. 2019

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The reactions of organic azides with diaryl(dihalo)diboranes(4) were explored, resulting in the observation of a number of surprising reactivity patterns. The reaction of phenyl azide with 1,2-diaryl-1,2-dihalodiboranes(4) resulted in the formation of five-membered rings comprising diboryl-triazenes with retention of the boron–boron bond, while the reaction of the peculiar 1,1-di(9-anthryl)-2,2-difluorodiborane(4) with phenyl azide yielded a six-membered ring bearing a diboryl-triazene, whereby the B–B bond was ruptured by the insertion of an arylnitrene-like reactive intermediate. Both types of heterocycles feature unprecedented connectivity patterns and are very rare examples of boryl triazenes beyond the more common 1,2,3-triazolatoboranes. They are also the product of a unique type of aryl migration from a boron center to the phenyl azide γ-nitrogen center. Lastly, the substitution of 1,2-diaryl-1,2-dihalodiboranes(4) with azide groups, using trimethylsilyl azide as the transfer reagent, yielded boryl-tetrazaboroles and diboryldiazadiboretidines (as side-products), invoking the intermediacy of the first N-boryl-substituted iminoboranes, which are BN isosteres of monoborylated alkynes. The synthetic results are complemented with mechanistic proposals derived from quantum-chemical calculations.

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“…When treated with 1,2‐dihalodiboranes(4), Pt 0 complexes are known to form diborane(4)yl complexes by (sometimes reversible) oxidative addition of the boron–halogen bond or bis(boryl) complexes by oxidative addition of the B−B bond . When attempting to synthesize diboron‐bridged complexes in a similar manner from the reaction of 1 with 1,2‐dihaloboranes(4), no reaction was observed with 1,2‐dibromo‐1,2‐diduryldiborane(4), while the reaction with B 2 Br 4 resulted solely in the formation of 2‐Br (Scheme a).…”

Section: Figurementioning

confidence: 99%

Boranediyl‐ and Diborane(4)‐1,2‐diyl‐Bridged Platinum A‐Frame Complexes

Brunecker

Müssig

Arrowsmith

et al. 2020

Chemistry A European J

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Diplatinum A-frame complexes with ab ridging (di)boron unit in the apex position were synthesized in a single step by the doubleo xidative addition of dihalo(di)borane precursors at ab is(diphosphine)-bridged Pt 0 2 complex. While structurally analogous to well-known m-borylene complexes, in which delocalized dative three-centertwo-electronM-B-M bonding prevails,t heoretical investigationsi ntot he natureo fP t ÀBb onding in these A-frame complexes show them to be rare dimetalla(di)boranes displaying two electron-sharing PtÀB s-bonds. This is experimentally reflected in the low kinetic stability of these compounds, which are pronet ol oss of the (di)boron bridgehead unit.

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Reactivity of Tetrahalo- and Difluorodiboranes(4) toward Lewis Basic Platinum(0): Bis(boryl), Borylborato, and Doubly Boryl-Bridged Platinum Complexes

Cited by 17 publications

References 89 publications

Stable Lewis Base Adducts of Tetrahalodiboranes: Synthetic Methods and Structural Diversity

Stable Lewis Base Adducts of Tetrahalodiboranes: Synthetic Methods and Structural Diversity

Synthesis of Complex Boron–Nitrogen Heterocycles Comprising Borylated Triazenes and Tetrazenes Under Mild Conditions

Boranediyl‐ and Diborane(4)‐1,2‐diyl‐Bridged Platinum A‐Frame Complexes

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