Diboron compounds stability

The presence of dialkylamino groups in mixed alkyl-amino or aryl-amino diboron compounds confer considerable thermal stability. Brotherton and his co-workers found that l,2-bis(dimethylamino)-l,2-diethyldiborane(4) is stable to about 140° C. At 200°C slow decomposition occurs, probably a disproportionation ... 

Figure 33 Observed stability constants (Kabs) of the diboronic acid sensors 140fn=3j-145fn—8) and the monoboronic acid reference compound 146(pyrene) (denoted n=ref) with the D-configuration of glucose and its derivatives.

The observed stability constants ( obs) of sensor 147(phenanthrene pyrene) (with Xex=299 nm and >,ex=342 nm) were calculated by fitting the emission intensities at 417 nm V5. concentration of saccharide curves and are given in Table 5. The observed stability constants (A obs) for the diboronic acid sensor 147(phenanthrene pyrene) ( ex=299 and 342 um) with D-glucose were enhanced relative to those of the monoboronic acid reference compounds 146(pyrene) and 153(phenanthrene)> while the observed stability constants (Aobs) for the diboronic acid sensor... 

To help visualize the trends of the observed stability constants (. fobs) in Tables 7 and 8, the stability constants of the diboronic acid sensors 148(pyrene)-152(2-naphthaiene) arc rcportcd in Figurc 40 divided by the stability constants of the analogous monoboronic acid reference compounds... 

Figure 40 Observed stability constants (K hs) of the diboronic acid sensors 148(pyr j-152(2. ap/it/iaiene) divided by the observed stability constants (Kobs) of the corresponding monoboronic acid reference compounds (pyrene) l (phencmthrerte) (2-naphthalerte) iO yield relative ValueS With saccharides. The n-configuration of the monosaccharides was used throughout this evaluation.

Compounds 66 and 67 typically reacted through the boron-boron multiple bond to afford n-complexes with coinage or alkali metals (68 and 69, Figure 5.10). Additionally, complexes 62, 66, and 67 were shown to undergo simultaneous B-B bond cleavage/cycloaddition reactions by oxidation with elemental sulfur or selenium (70 and 71). " Diboron complexes 66 and 67 also reacted with carbon monoxide and isonitriles, respectively, to afford NHC-stabilized bis(boralactone) 72 and bis(boraketenimine) 73. ... 

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