The Preparation and Properties of Some Tetracoordinate Boron Compounds. The Pseudo-Metal Ion Concept

Influence of the electron donor groups on the optical and electrochemical properties of borondifluoride complexes of curcuminoid derivatives: a joint theoretical and experimental study

“…Their optical [1][2][3][4][5][6][7][8][9][10][11] and electrochemical [11][12][13][14][15][16] properties have been described in previous studies and it has been shown that they can be used as versatile uorophores, 1-5 electron acceptors 17,18 in one-electron transfer processes 19 or in chargetransport materials in both organic eld effect transistors and organic light emitting diodes. [20][21][22][23][24][25] One-electron reduction proceeds via the formation of a radical anion where the unpaired electron is delocalized on the p-system of the boroncontaining six-membered chelate ring, as demonstrated by electron paramagnetic resonance studies.…”

Structural studies of organoboron compounds. XII. Crystal and molecular structures of (acetylacetonato)diphenylboron and (tropolonato)diphenylboron

“…Colorless crvstals of the triclinic form were isolated directly boron, 1, and (tropolonato)diphenylboron~ 2, are stabilized by both intramolecular 0 + B interactions and by electron delocalization in the chelate rings. The chemical and physical properties of these compounds are well documented (12)(13)(14)(15)(16)(17) and references therein).…”

Structural studies of organoboron compounds LXI. Synthesis of (alkylideniminoxy)- diarylboranes and crystal and molecular structure of dimeric (ethylideniminoxy)-bis(4-methoxyphenyl)borane [3,3,6,6-tetrakis(4-methoxyphenyl)-2,5-diethylidene-1,4-dioxa-2,5-diazonia-3,6-diboratacyclohexane]

“…The dimerization of 1 was later recognized as a consequence of cyclic stabilization by 0-H.-N hydrogen bonding in associates like 2 (2). Six-membered dimers of the general formula 2 were also found in the solid state by X-ray crystallographic analyses of various oximes (3) and were further characterized (4) by ab initio calculations of the most simple example, formaldoxime (2, R1 = R2 = H), along with a neutron diffraction study of glyoxime at 9 K. It is known that iminoxyboranes 3, which can be envisaged as borinic acid esters of oximes, are able to dimerize in an equilibrium reaction to the six-membered BONBON ring compounds 4 if steric and electronic conditions allow the formation of a twofold Lewis acid-base adduct (5)(6)(7)(8)(9).2 Formally, in the cyclic dimer 4 both of the "chelated" protons in 2 are replaced by borenium ions (R2B+), in accordance with the concept of the chelation of "pseudometal" cations (10). In the solid state, the complete association of 3 should allow a structural characterization of the l~revious paper in this series: ref.…”