Tetrakis-(N-pyrrolyl)methane : structurally important member of the C(NR2)4 family

"It has been predicted that the polymorphic forms of carbon nitride are harder than diamond [1], and this auspicious speculation has prompted huge efforts to reliably prepare C3N4 [2]. Recently, there have been a number reports in surface science literature about the existence of carbon nitride phases as thin layers [3]. Carbon nitride is expected to have each nitrogen atom connected to three carbon atoms and each carbon atom connected to four nitrogen atoms. Although tertiary amines (NC3) are very common, compounds containing C(NR2)4 units are rare in organic chemistry, and very few examples have appeared in the literature (e.g., structures 1 [4], 2 [5], and 3 [6], Fig. 1). In this communication, we describe an interesting member of this class, namely tetrakis-(N-pyrrolyl)methane 4, comparable with the time-honored tetraphenyl analogue and prototype for a large family of tetrakis-N-[5-ring]heteroaryl methanes of which tetrakis-N-pyrazolyl methane 2 [5] appears to be the only other known member." --Introduction.