| abstract |
A compound having the formula (I) where each of R 1 , R 2 , R 3 and R 4 is independently C 6 -C 18 aryl-, C 5 -C 8 cycloalkyl-, C 6 -C 18 aryl having at least one C 1 -C 20 alkyl substituent, C 5 -C 8 cycloalkyl having at least one C 1 -C 20 alkyl sυbstituent, C 4 -C 20 branched alkyl-, C 16 -C 20 linear alkyl-, RO—, —NRR′, —PRR′, —SR, fluoro substituted forms thereof, and perfluoro forms thereof: and R 5 is C 6 -C 18 aryl-, C 5 -C 8 cycloalkyl-, C 6 -C 18 aryl having at least one C 1 -C 20 alkyl substituent, C 5 -C 8 cycloalkyl having at least one C 1 -C 20 alkyl substituent, C 3 -C 20 branched alkyl-, C 2 -C 30 linear alkyl-, fluoro substituted forms thereof, and perfluoro forms thereof; where R and R′ are each independently C 6 -C 18 aryl-, C 5 -C 8 cycloalkyl-, C 6 -C 18 aryl having at least one C 1 -C 20 alkyl substituent, C 5 -C 8 cycloalkyl having at least one C 1 -C 20 alkyl substituent, C 4 -C 20 branched alkyl-, C 2 -C 30 linear alkyl-, fluoro substituted forms thereof, and perfluoro forms thereof; A is N, P, S, or O with the proviso that when A is S, R 2 is a nullity; and M is B, Al, Ga or In. |