92011-77-3Relevant academic research and scientific papers
Borate photoinitiators from polyboranes
-
, (2008/06/13)
Compounds of the formula I STR1 in which n and o are a number from 0 to 50, m is a number from 1 to 50, u and v are 0 or 1, and at least one of the indices u and v is 1, R1, R2, R2a, R3 and R4 independently of one another are, for example, aromatic hydrocarbons, R5, if n and o are 0, is for example C1 -C12 alkyl and, if n and/or o are greater than 0, or if n and o are 0 and at the same time only one index u or v is 1, R5 may additionally, for example, be an aromatic hydrocarbon, at least one of the radicals R1, R2, R2a, R3, R4 and R5 being an aromatic hydrocarbon radical which is sterically hindered ortho to the boron atom, X is, for example, C1 -C20 alkylene, phenylene, biphenylene, etc., and Z is a radical which is able to form positive ions, are suitable as photoinitiators, both the compounds per se and their combination with dyes or other electron acceptors. Furthermore, the polyborane precursors of these borates possess, together with borate salts, photoinitiating properties.
Organoboron Redox Systems
Schulz, Andreas,Kaim, Wolfgang
, p. 1863 - 1868 (2007/10/02)
The compounds BPh3-nMesn, n = 0 - 3 (1-4), AlPh3 (5), AlMes3 (6), 1,4-Mes2B-C6H4-NMe2 (7), 1,4-Mes2B-C6H4-BMes2 (8), and 4,4'-Mes2B-C6H4-C6H4-BMes2 (9) were studied by UV/VIS spectroscopy and cyclic voltammetry.A single mesityl substituent (Mes) is sufficient to permit reversible electron transfer at the electrode surface and to stabilize the singly reduced, i.e. radical anionic form of triarylboranes by preventing an increase of the coordination number at boron.This electrochemical effect is not observed for the aluminium analogues.In contrast to the kinetic stabilization of triarylborane anion radicals by mesityl substituents stands the slight thermodynamic destabilization by this electron donor group.Disubstituted aromatics such as 8 and 9 show two-step reversible redox behaviour.Spectroscopic and electrochemical results reveal that the dimesitylboryl substituent is a strong ? acceptor, comparable to the nitrile group. - Key Words: Electrochemistry / Organoboron compounds / Radical ions / Substituent effects
