Mono- and Polynuclear Boron Dications

Lin, Ya‐Fan; Chiu, Chi-Tsung

doi:10.1246/cl.170154

Cited by 16 publications

(13 citation statements)

References 72 publications

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“…It is noteworthy that these ionic compounds were not observed as products of the 1:2 reactions of B 2 Cl 4 with IMes or IDip, which suggests that they may only be accessible from the decomposition of the mono‐adducts. Although cationic monoboron(III) species, which are significantly more Lewis acidic than neutral boranes, are well‐known and have found applications in catalysis, in particular, cationic diboron species like these remain relatively rare. Most known examples are dicationic bis(base)‐stabilized sp 2 –sp 2 or sp 3 –sp 3 diboron(II) compounds, in which the electron‐deficient boron centers are stabilized through π‐donation by neutral and/or anionic nitrogen ligands, whereas Kinjo reported a unique tetrakis(carbene)‐stabilized sp 3 –sp 3 diboron dication .…”

Section: Resultsmentioning

confidence: 99%

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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Section: Resultsmentioning

confidence: 99%

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 research topic which is coherent with the study of mononuclear doubly charged complexes of boron is the investigation of dinuclear boron dications. This field may be divided into two major subcategories: (i) dications with two heteroatom‐bridged boron atoms and (ii) dications with a boron–boron bond . For the former, hydride‐ and oxygen‐bridged examples are known .…”

Section: Figurementioning

confidence: 99%

Three‐Coordinate Boron(III) and Diboron(II) Dications

Franz

Szilvási

Pöthig

et al. 2018

Chemistry A European J

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The enhanced electron-donor properties of the bulky bisimino ligand 1,2-(L N) -C H (1; L =1,3-bis(mesityl)-imidazolin-2-ylidene), mesityl=2,4,6-trimethylphenyl) were exploited for the stabilization of elusive electron-deficient and low-coordinate boron dication species. The reaction of 1 with PhBBr or (B(Cl)NMe ) afforded a dicationic mononuclear boron(III) complex or a dicationic dinuclear boron(II) complex, respectively (4 , 6 ). The bonding situations of 4 and 6 were examined by means of single crystal X-ray diffraction analysis, as well as theoretical methods. Significant allocation of positive charge density into the ligand system was diagnosed for both dications. However, the metalloid-centered Lewis acidity of the dications was confirmed via hydride transfer reactions.

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“…[6,97,102] Theb icyclic guanidinate substituent hpp efficiently delocalizes the positive charge,t hereby enabling the stabilization of highly positively charged cationic boranes (enriching the field of cationic boron compounds currently being intensively studied [90,91,[106][107][108][109][110][111] ). [6,97,102] Theb icyclic guanidinate substituent hpp efficiently delocalizes the positive charge,t hereby enabling the stabilization of highly positively charged cationic boranes (enriching the field of cationic boron compounds currently being intensively studied [90,91,[106][107][108][109][110][111] ).…”

Section: Discussionmentioning

confidence: 99%

Electron‐Deficient Triborane and Tetraborane Ring Compounds: Synthesis, Structure, and Bonding

Himmel

2019

Angew Chem Int Ed

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Electron‐deficient small boron rings are unique in their formation of σ‐ and π‐delocalized electron systems as well as the avoidance of “classical” structures with two‐center‐two‐electron (2c,2e) bonds. These rings are tolerant of several skeletal electron numbers, which makes their redox chemistry highly interesting. In the past few decades, a range of stable compounds have been synthesized with various electron numbers in their B3 and B4 cores. The electronic structures were evaluated by quantum‐chemical calculations. On the other hand, the chemistry of these rings is still very much underdeveloped, being generally limited to the protonation and redox reactions of individual systems. The linkage of several B3 and/or B4 ring systems should give compounds with attractive electronic properties, thus leading the way to novel boron‐based materials. By summarizing important experimental and theoretical results, this Review intends to provide the basis for the exploration of the chemistry of these rings and, in particular, their integration into larger molecular architectures.

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Mono- and Polynuclear Boron Dications

Cited by 16 publications

References 72 publications

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

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

Three‐Coordinate Boron(III) and Diboron(II) Dications

Electron‐Deficient Triborane and Tetraborane Ring Compounds: Synthesis, Structure, and Bonding

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