81 research outputs found
Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization
The desymmetrization of the cyclic
(alkyl)Â(amino)Âcarbene-supported
diboracumulene B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub> (cAAC<sup>Me</sup> = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene)
by monoadduct formation with IMe<sup>Me</sup> (1,3-dimethylimidazol-2-ylidene)
yields the zerovalent sp–sp<sup>2</sup> diboron compound B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>), which provides
a versatile platform for the synthesis of novel symmetrical and unsymmetrical
zerovalent sp<sup>2</sup>–sp<sup>2</sup> diboron compounds
by adduct formation with IMe<sup>Me</sup> and CO, respectively. Furthermore,
B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>) displays
enhanced reactivity compared to its symmetrical precursor, undergoing
spontaneous intramolecular C–H activation and facile twofold
hydrogenation, the latter resulting in B–B bond cleavage and
the formation of the mixed-base parent borylene (cAAC<sup>Me</sup>)Â(IMe<sup>Me</sup>)ÂBH
Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization
The desymmetrization of the cyclic
(alkyl)Â(amino)Âcarbene-supported
diboracumulene B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub> (cAAC<sup>Me</sup> = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene)
by monoadduct formation with IMe<sup>Me</sup> (1,3-dimethylimidazol-2-ylidene)
yields the zerovalent sp–sp<sup>2</sup> diboron compound B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>), which provides
a versatile platform for the synthesis of novel symmetrical and unsymmetrical
zerovalent sp<sup>2</sup>–sp<sup>2</sup> diboron compounds
by adduct formation with IMe<sup>Me</sup> and CO, respectively. Furthermore,
B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>) displays
enhanced reactivity compared to its symmetrical precursor, undergoing
spontaneous intramolecular C–H activation and facile twofold
hydrogenation, the latter resulting in B–B bond cleavage and
the formation of the mixed-base parent borylene (cAAC<sup>Me</sup>)Â(IMe<sup>Me</sup>)ÂBH
Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization
The desymmetrization of the cyclic
(alkyl)Â(amino)Âcarbene-supported
diboracumulene B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub> (cAAC<sup>Me</sup> = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene)
by monoadduct formation with IMe<sup>Me</sup> (1,3-dimethylimidazol-2-ylidene)
yields the zerovalent sp–sp<sup>2</sup> diboron compound B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>), which provides
a versatile platform for the synthesis of novel symmetrical and unsymmetrical
zerovalent sp<sup>2</sup>–sp<sup>2</sup> diboron compounds
by adduct formation with IMe<sup>Me</sup> and CO, respectively. Furthermore,
B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>) displays
enhanced reactivity compared to its symmetrical precursor, undergoing
spontaneous intramolecular C–H activation and facile twofold
hydrogenation, the latter resulting in B–B bond cleavage and
the formation of the mixed-base parent borylene (cAAC<sup>Me</sup>)Â(IMe<sup>Me</sup>)ÂBH
Diboran(4)yl Platinum(II) Complexes
The
platinum diboran(4)Âyl complexes <b>1</b>–<b>3</b> have been prepared by the selective oxidative addition of one B–Hal
bond in aryl-substituted diboranes(4) Hal<sub>2</sub>B<sub>2</sub>Ar<sub>2</sub> (Hal = Cl, Ar = mes, dur; Hal = I, Ar = mes). Because
of the electron deficiency of the remote B2 atom, all species show
a rare dative Pt–B bonding interaction, whose magnitude is
strongly dependent on the nature of the halide substituent
Synthesis and Structure of a Carbene-Stabilized Boraallene Coordinated to Rhodium
Reaction of the (B,C-η<sup>2</sup>)-1-aza-2-borabutatriene rhodium complex <b>1</b> with
1,3-dimethylimidazol-2-ylidene) (<i>I</i>Me, <b>2</b>) afforded the N-heterocyclic carbene-stabilized (C,C-η<sup>2</sup>)-1-boraallene rhodium complex <b>3</b>, which has been
characterized in solution and by X-ray crystallography. Density functional
theory calculations were carried out to elucidate the observed base-induced
B–C to C–C coordination mode shift, which suggested
that the latter is 25 kJ/mol lower in energy
Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization
The desymmetrization of the cyclic
(alkyl)Â(amino)Âcarbene-supported
diboracumulene B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub> (cAAC<sup>Me</sup> = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene)
by monoadduct formation with IMe<sup>Me</sup> (1,3-dimethylimidazol-2-ylidene)
yields the zerovalent sp–sp<sup>2</sup> diboron compound B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>), which provides
a versatile platform for the synthesis of novel symmetrical and unsymmetrical
zerovalent sp<sup>2</sup>–sp<sup>2</sup> diboron compounds
by adduct formation with IMe<sup>Me</sup> and CO, respectively. Furthermore,
B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>) displays
enhanced reactivity compared to its symmetrical precursor, undergoing
spontaneous intramolecular C–H activation and facile twofold
hydrogenation, the latter resulting in B–B bond cleavage and
the formation of the mixed-base parent borylene (cAAC<sup>Me</sup>)Â(IMe<sup>Me</sup>)ÂBH
Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization
The desymmetrization of the cyclic
(alkyl)Â(amino)Âcarbene-supported
diboracumulene B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub> (cAAC<sup>Me</sup> = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene)
by monoadduct formation with IMe<sup>Me</sup> (1,3-dimethylimidazol-2-ylidene)
yields the zerovalent sp–sp<sup>2</sup> diboron compound B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>), which provides
a versatile platform for the synthesis of novel symmetrical and unsymmetrical
zerovalent sp<sup>2</sup>–sp<sup>2</sup> diboron compounds
by adduct formation with IMe<sup>Me</sup> and CO, respectively. Furthermore,
B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>) displays
enhanced reactivity compared to its symmetrical precursor, undergoing
spontaneous intramolecular C–H activation and facile twofold
hydrogenation, the latter resulting in B–B bond cleavage and
the formation of the mixed-base parent borylene (cAAC<sup>Me</sup>)Â(IMe<sup>Me</sup>)ÂBH
Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization
The desymmetrization of the cyclic
(alkyl)Â(amino)Âcarbene-supported
diboracumulene B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub> (cAAC<sup>Me</sup> = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene)
by monoadduct formation with IMe<sup>Me</sup> (1,3-dimethylimidazol-2-ylidene)
yields the zerovalent sp–sp<sup>2</sup> diboron compound B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>), which provides
a versatile platform for the synthesis of novel symmetrical and unsymmetrical
zerovalent sp<sup>2</sup>–sp<sup>2</sup> diboron compounds
by adduct formation with IMe<sup>Me</sup> and CO, respectively. Furthermore,
B<sub>2</sub>(cAAC<sup>Me</sup>)<sub>2</sub>(IMe<sup>Me</sup>) displays
enhanced reactivity compared to its symmetrical precursor, undergoing
spontaneous intramolecular C–H activation and facile twofold
hydrogenation, the latter resulting in B–B bond cleavage and
the formation of the mixed-base parent borylene (cAAC<sup>Me</sup>)Â(IMe<sup>Me</sup>)ÂBH
Diboran(4)yl Platinum(II) Complexes
The
platinum diboran(4)Âyl complexes <b>1</b>–<b>3</b> have been prepared by the selective oxidative addition of one B–Hal
bond in aryl-substituted diboranes(4) Hal<sub>2</sub>B<sub>2</sub>Ar<sub>2</sub> (Hal = Cl, Ar = mes, dur; Hal = I, Ar = mes). Because
of the electron deficiency of the remote B2 atom, all species show
a rare dative Pt–B bonding interaction, whose magnitude is
strongly dependent on the nature of the halide substituent
Synthesis of the First Heteroaryl-Substituted Boryl Complexes: Strong Stabilizing Effects of Boron–Aryl π‑Conjugation
The
first examples of heteroarylboryl complexes were prepared and have
been found to be unreactive toward a range of strong reductants, strong
Lewis bases, and halide-abstraction reagents. The inertness of the
complexes is attributed to strong π-conjugation between the
π-basic heteroaryl groups and the π-acidic boron atom.
This hypothesis is supported by comparison of the structural and spectroscopic
properties of the heteroarylboryl complexes with analogous previously
reported homoarylboryl complexes, with the former showing greater
coplanarity of the aryl ring with the boron atom and much less facile
reactivity
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