Macropolyhedral Nickelaboranes from the Metal-Assisted Fusion of KB₉H₁₄

Abstract

The reaction of K[arachno-B 9 H 14 ] with [NiCl 2 (dppe)] produces four new 19-vertex macropolyhedral metallaboranes that result from borane cluster fusion: [9′-(dppe)-9′-Ni-anti-B 18 H 20 ] (1) and isomeric [11′-(dppe)-11′-Ni-syn-B 18 H 20 ] (2), together with the chlorine-substituted derivative of 1, [5′-Cl-9′-(dppe)-9′-Ni-anti-B 18 H 19 ] (3), and the 18-vertex cluster compound [7′-(dppe)-7′-anti-NiB 17 H 21 ] (4). Two closo 10-vertex single-cluster species, [1-(dppe)-1closo-NiB 9 H 7 Cl 2 ] ( 5) and [1-(dppe)-1-closo-NiB 9 H 7 Cl(OH)] (6), were also isolated from the reaction. The production of the metalated syn-octadecaborane isomer 2 from the fusion of two arachno-nonaborate clusters is the first such case to be observed; in all other reported cases fusion has resulted in products with the anti-octadecaboranyl bis-nido configuration.

A simple and high-yield route to iridium, rhodium, osmium and rutheniumnido-6-metalladecaborane compounds

“…However, DFT-GIAO calculations are helpful here in that, whereas the error in the calculated value of the absolute chemical shift may be as large as the difference between the measured chemical shifts, the relative ordering of the calculated values often follows the pattern seen in the observed chemical shifts. 43 Thus, the B4 and B3 resonances at  B +89.5 and +86.7 ppm, which have calculated values of  B +94.1 and +92.4 ppm, respectively, are a good example. The lower-field boron resonance of  B +89.5 ppm has an attached terminal hydrogen atom that exhibits a higher field proton resonance at  H +8.58 ppm (H4); whereas the relatively higherfield boron,  B +86.7 ppm, is bound to the terminal hydrogen atom that gives a lower-field proton signal at +9.36 ppm.…”

“…This high-frequency 11 B-to-1 H correlation, found in the inequivalent upper stack of boron vertices, is a spectroscopic signature of 10-vertices isoclosometalladecaboranes, which serve, therefore, as a diagnostic. 43 We should expect that the assignments within each closely spaced set of measured resonances are somewhat uncertain. However, DFT-GIAO calculations are helpful here in that, whereas the error in the calculated value of the absolute chemical shift may be as large as the difference between the measured chemical shifts, the relative ordering of the calculated values often follows the pattern seen in the observed chemical shifts.…”

Macropolyhedral Chalcogenaboranes: Insertion of Selenium into the Isomers of B18H22

“…were too broad and too closely spaced to allow efficient assignment of the peaks from [ 11 B− 11 B] COSY correlations, but this compound does present a useful example of the utility of multielement DFT/GIAO simulation of NMR spectra and its use in assigning measured resonances to their positions in the cluster. 22,23 The technique is applied to the assignments made for other compounds herein. Thus, tentative assignments for NMR data are made by the relative ordering of both 11 H) +2.90 ppm compared to that for BH(5) at δ( 1 H) +2.52 ppm.…”

“…Figure below shows a stick diagram of the 11 B chemical shifts together with those of related compounds for comparison. Many of the boron resonances were too broad and too closely spaced to allow efficient assignment of the peaks from [ 11 B– 11 B] COSY correlations, but this compound does present a useful example of the utility of multielement DFT/GIAO simulation of NMR spectra and its use in assigning measured resonances to their positions in the cluster. , The technique is applied to the assignments made for other compounds herein.…”

Early events in the mechanism of single-source chemical vapor deposition of zirconium and hafnium diboride: a computational investigation

“…Apart from their relevance to the CVD reactions, these findings present an interesting avenue towards metal-assisted synthesis of higher boranes, a topic of interest in polyhedral boron cluster chemistry. [50][51][52][53] The lower-energy pathway is especially interesting, in part because up to the formation of Hf-2f it is both thermodynamically and kinetically favored over any possible avenues of BH 3 dissociation. No clear continuation past Hf-2f has presented itself yet -although multiple reactions are possible, all of them are high-energy.…”