Interplay of donor–acceptor interactions in stabilizing boron nitride compounds: insights from theory

Abstract

The stability of a variety of linear and cyclic (BN)n (n = 1-3) adducts with N-heterocyclic carbene (ImMe2; ImMe2 = [(HCNMe)2C:]), N-heterocyclic olefin (ImMe2CH2) and Wittig (Me3PCH2) donors has been examined using M05-2X/cc-pVTZ computations. The strength and nature of the bonds have been investigated using natural bond orbital (NBO) and atoms-in-molecules (AIM) analyses. Complementary energy decomposition analysis (EDA-NOCV) has been carried out based on BP86/TZ2P computations. In agreement with NBO and AIM analyses, the orbital interaction energy obtained from EDA contributes at least 50% to the total attractive interactions for the carbon-boron bonds indicating their largely covalent nature. The feasibility of isolating monomeric (BN)n units using a donor/acceptor protocol was also investigated in a series of adducts of the general form: LB·(BN)n·BH3 and LB·(BN)n·W(CO)5 (n = 1-3; LB = Lewis bases). Moreover, EDA-NOCV analysis of ImMe2·BN·W(CO)5 and ImMe2·B3N3·W(CO)5 shows that the carbene-boron bonds are stronger in the presence of W(CO)5 as a Lewis acid mainly because of a dramatic decrease in the amount of Pauli repulsion rather than an increase in the electrostatic/orbital attraction terms.

Controllable modulation of precursor reactivity using chemical additives for systematic synthesis of high-quality quantum dots

“…1a). A B-S bond is employed, because the bond length between boron and the adjacent atom can be altered upon the coordination of a Lewis base (LB) to boron 38 . We expect that LBs with a higher affinity to boron weaken the B-S bond to a greater extent, increasing the reactivity of the precursor.…”

Encapsulating Inorganic Acetylene, HBNH, Using Flanking Coordinative Interactions

“…The N 2 elimination process central to the current study was discovered in an attempt to form the electrophilic azidoborane adduct IPr⋅B(OTf) 2 N 3 from the addition of two equivalents of MeOTf14 to the known azidoborane15 IPr⋅BH 2 N 3 ( 1 ) (IPr=[(HCNDipp) 2 C:], Dipp=2,6‐ i Pr 2 C 6 H 3 ; OTf − =OSO 2 CF 3 ). It was hoped that reducing IPr⋅B(OTf) 2 N 3 would afford an unstable boron(I) species that would yield oligomeric adducts of [IPr⋅(BN)] x after loss of dinitrogen 16. However, when IPr⋅BH 2 N 3 ( 1 ) was reacted with MeOTf, gas evolution was noted and a new product was formed that contained a nitrogen‐bound methyl group.…”

“…It was hoped that reducing IPr·B(OTf) 2 N 3 would afford an unstable boron(I) species that would yield oligomeric adducts of [IPr·(BN)] x after loss of dinitrogen. [16] However,w hen IPr·BH 2 N 3 (1)w as reacted with MeOTf,g as evolution was noted and an ew product was formed that contained an itrogen-bound methyl group.T his product proved to be thermally unstable in solution at room temperature,y et at À35 8 8Cc olorless crystals suitable for X-ray crystallography were obtained, revealing the generation of the formal boraiminium adduct [IPr·HB=NH(Me)]OTf (2) (Scheme 2; Figure 1). …”

Reactivity of a coordinated inorganic acetylene unit, HBNH, and the azidoborane cation [HB(N3)]+

“…In this Edge Article we introduce a more reactive HBNH adduct and describe our attempts to convert this species into LB·BN·LA complexes (LA = Lewis acid; LB = Lewis base; Scheme 1); in addition we investigate the reactivity of the donor-stabilized azidohydride boronium cation [BH(N 3 )] + . 9 The ultimate goal of our program would be to use these newly developed B–N species for the mild solution-based preparation of bulk boron nitride (Scheme 1). BN and its nanodimensional analogues are highly coveted in the context of advancing modern electronics due to their refractory nature, and desirable electronically insulating and heat dissipating properties.…”