| abstract |
A compound having a four-coordinate boron atom to which is connected a first C 3 -C 25 substituent, a second C 3 -C 25 substituent and a bridging substituent comprising from eight to forty non-hydrogen atoms and having two bonds to the boron atom; n wherein: (i) each of the first and second C 3 -C 25 substituents is bonded to the boron atom through a carbon, nitrogen or oxygen atom, and, optionally the first and second C 3 -C 25 substituents are connected to form a single substituent having two bonds to the boron atom; (ii) at least one of the first and second C 3 -C 25 substituents is a C 6 -C 25 aromatic substituent; (iii) said aromatic substituent comprises at least one nitrogen atom which is bonded only to carbon or boron atoms; and (iv) the bridging substituent has at least one oxygen, nitrogen, sulfur or phosphorus atom bonded to the boron atom and at least one aromatic ring. |