Synthetic and structural chemistry of amidinate-substituted boron halides

Abstract

The following new amidinate-substituted boron halides are reported: [PhC{N(SiMe(3))}(2)]BCl(2)(6), [MeC{NCy}(2)]BCl(2)(10), [Mes*C{NCy}(2)]BCl(2)(11), [MeC{N(i)Pr}(2)]BCl(2)(12), and [FcC{NCy}(2)]BBr(2)(13). Compound 6 was prepared via the trimethylsilyl chloride elimination reaction of BCl(3) with N,N,N'-tris(trimethylsilyl)benzamidine, and compounds 10-12 were prepared by salt metathesis between the lithium amidinates [RC(NR')(2)]Li and BX(3). Compound 13 was prepared via the insertion of 1,3-dicyclohexylcarbodiimide into the B-C bond of ferrocenyldibromoborane FcBBr(2). The molecular structures of 6, 10, 11, 13 and the known compound [PhC{N(SiMe(3))}(2)]BBr(2)(1) were established by single-crystal X-ray diffraction.

Stepwise Nucleophilic Substitution to Access Saturated N-heterocyclic Carbene Haloboranes with Boron–Methyl Bonds

“…7 crystallizes in the orthorhombic space group Pbca . In the four-membered BNCN ring, the N1–B1–N2 angle and the B–N distances are 82.60(13)° and average 1.571 Å, respectively, which are similar to those for the other reported amidinatoborane complexes . The distance between the tetracoordinated boron and the methyl carbon is 1.646(5) Å, which is slightly longer than that in 3 .…”

A new bulky iminophosphonamide as an N,N′-chelating ligand: synthesis and structural characterization of heteroleptic group 13 element complexes

“…The 11 B NMR spectrum of 4 exhibits a singlet at 7.42 ppm, which is typical of neutral molecules reported for four coordinated boron atoms and is in good agreement with values reported for closely related (guanidinate)borondihalides. 33,34 The 31 P{ 1 H} NMR spectrum of complexes 4-6 showed signals at 39.81 (4), 34.92 (5) and 38.52 (6) ppm, respectively, and these values are significantly downfield shifted upon coordination with the metal as compared to that of compound 1 (7.52 ppm). The 27 Al NMR for 5 showed a broad signal at 70.9 ppm (Δ 1/2 = 1920 Hz).…”

Synthesis and structure of two new (guanidinate)boron dichlorides and their attempted conversion to boron(i) derivatives

“…21 The N-B-N bite angles for the guanidinate rings are 83.69 (14) and 83.4(3) • for 14 and 15, respectively, and are more acute than those reported by Aldridge et al 16 By contrast, the bite angles in closely related amidinate rings fall within the range of approximately 85-86 • . 17, 22 The average N-B-Cl bond angles are 114.90(16) • and 117.6(3) • for 14 and 15, respectively, hence the geometry about the boron atom is appreciably distorted from that of a regular tetrahedron. Finally, it is worth noting that the C(1)-N(3) distances of 1.342(3) ( 14) and 1.353(6) A ˚(15) are remarkably short and therefore consistent with the idea of a substantial contribution from the iminium/diamide resonance form to the bonding descriptions of both compounds.…”