Terphenyl substituents

Two independent routes to magnesium amidinates containing very bulky terphenyl substituents have been developed, yielding both mono- and bis(amidinate) magnesium complexes. As shown in Scheme 17, the free amidine reacted cleanly with 0.5 equivalents of dibutylmagnesium in toluene to form the bis (amidinate) in moderate yield. The highly soluble compounds was recrystallized from hexanes as clear, colorless crystalline blocks. ... 

In a related study, sterically bulky amidinate ligands containing terphenyl substituents on the backbone carbon atoms have been utilized in organoalumi-num chemistry. Mono(amidinate) dialkyl complexes were generated as shown in... 

When a suspension of indium monochloride in THF is treated with LiC6H3-2,6-Mes2 at -78 °C the unusual cluster In8(C6H3-2,6-Mes2)4 (49) is produced. As may be seen this has a distorted cubane arrangement of eight indium atoms where four of these atoms carry a terphenyl substituent. Although the formal... 

The cations 73 and 74 represent a class of silyl cations which are stabilized by intramolecular a -donation from the flanking aryl groups of the meta-terphenyl substituent. This offers the possibility to tune their reactivity by suitable choice of the substituent. Some evidence for this is provided by the high-field-shifted Si NMR resonance detected for cation 73d with the electron-rich pentamethylaryl substituent compared to that of the xylyl-substituted cation 73a (8 Si (73d) = 58.6 vs. S Si (73a) = 80.1). 

---