Swollen Polyhedral Volume of the anti-B₁₈H₂₂ Cluster via Extensive Methylation: anti-B₁₈H₈Cl₂Me₁₂

Abstract

Methylation of anti-B 18 H 22 (1) affords the first example of alkyl substitution of terminal hydrogen atoms on the fluorescent octadecaborane-22 molecule to give highly methylated 2,2′-Cl 2 -1,1′,

Unveiling the role of upper excited electronic states in the photochemistry and laser performance of anti-B18H22

“…7 Also, since the discovery of lasing from anti-B18H22, no further reports of other fluorescent boranes displaying laser emission have appeared despite other fluorescent borane species with comparable photophysical characteristics having been made. [4][5][6]8,9 In this sense, the ability of anti-B18H22 to function as a laser seems to be the exception rather than the rule with regard to luminescent boranes. All these considerations raise the question of what might be the main factors mitigating the development of borane-based lasers.…”

Macropolyhedral syn-B18H22, the “Forgotten” Isomer

“…Changes of interboron distances adjacent to the substituent are too subtle to be apparent, but they become more obvious when we measure the effect on geometrical parameters effectively encompassing the whole molecule, as a whole, i.e., on the distance between the centroids of the two subclusters of syn-B 18 H 22 , or on the distance between vertices from the opposite ends of the molecule, such as B(9)−B(9′). Such substituent metrics have also been estimated in terms of the overall cluster volume, 28,32 and it is anticipated that syn-B 18 H 22 with other substituents should also modify the photophysical properties. This study lays a solid foundation for further work in this direction.…”

“…Two of the largest known macropolyhedral boranes are the isomeric docosahydrooctadecaboranes B 18 H 22 . , They exhibit a unique molecular structure with two open faces and six acidic bridging hydrogen atoms (μ H -BB). − Their structural and chemical properties, together with their interaction with light, make B 18 H 22 a promising candidate for a wide range of applications, from energy storage, , semiconductor doping ,− to nano- and optoelectronic devices. − The molecular structure of B 18 H 22 can be viewed as two decaborane molecules condensed together, with each subcluster sharing atoms B(5) and B(6) in the decaborane numbering system, in common (Figure B,C). The isomer syn -B 18 H 22 on which this study focuses is a much less-studied (“forgotten”) system compared to its anti -B 18 H 22 isomer, and it has a 2-fold symmetry axis due to the fusion of two {B10} units sharing the B(5)–B(6) edge so that B(5)B(5′) and B(6)B(6′) (Figure B); in the anti -B 18 H 22 isomer, B(5)B(6′) and B(6)B(5′), which results in the inversion symmetry (Figure C). ,, What has stimulated most of the recent interest in anti -B 18 H 22 and its substituted derivatives has mainly been their luminescence properties. − Our interest in the “forgotten”, nonluminescent isomer, syn -B 18 H 22 , has been stimulated mainly by its unique geometry and size with respect to its use as constituents of purely borane, carbon-free self-assembled monolayers and its further use toward 2-dimensional membranes with thickness below 1 nm and with a 3D-aromatic character, as well as capping ligands of atomically precise metal nanoclusters, a newly emerging class of materials with adjustable geometry, size, and properties. , …”

The temperature dependence of the Photoluminescence stability of octadecaborane in polystyrene matrix thin films

“…Among others, the anchoring of stabilizing side substituents on the borane cage skeleton seems to be a suitable way. For example, the recently published extensive methylation increases the stability of these compounds significantly [8].…”