Symmetry-controlled rearrangements in Piedfort Units (PU) of 2,4,6-triaryloxy-1,3,5-triazines

Abstract

2,4,6-triaryloxy-1,3,5-triazines (POT) form in general molecular diads, termed as Piedfort Units (PU), in their crystals and their clathrates. Their bulky phenyl substituents (R = Me, F, Cl, Br, I, CN) in ortho, meta or para position substantially hinder internal rotations. Instead, non-crystallographic rotations (ncr) or translations (nct) are the bridges between the semirigid homologues or analogues, occasionally polymorphs. They occur in the space groups R3c (161), R 3 (148), P 3c1 (165), P6 3 /m (176), P 31c (163), P2 1 /c (14), Ia (9), and P 1 (2). In each group, the molecules are close to be isometrical, while these groups are linked by non-crystallographic symmetries termed morphotropism. The observed non-crystallographic symmetries are virtual between the homologues and real between their dimorphs. Real ncr's were also found between 4-RPOTs and their clathrate forms. It is demonstrated how e.g. toluene induces real nrc's in its clathrate with 4-IPOT.

A Quest towards Eccentric Piedfort Pairs

“…Hydrogen atoms other than the two bound to the stereogenic centres are omitted for clarity. Selected bond distances [Å ] and angles [deg]: CdÀN(1), 2.320(5); CdÀN(3), 2.373(5); CdÀCl(2), 2.4984 (14); CdÀN(2), 2.516(5); CdÀCl(1), 2.5686 (15); N(1)-CdÀN(3), 97.52 (19); N(1)-CdÀCl(2), 96.67 (13); N(3)-CdÀCl(2), 95.91 (12); N(1)-CdÀN(2), 71.01 (17); N(3)-CdÀN(2), 69.55 (16); Cl(2)-CdÀN(2), 158.73 (11); N(1)-CdÀCl(1), 154.69 (12); N(3)-CdÀCl(1), 89.04 (13); Cl(2)-CdÀCl(1), 106.98 (5); N(2)-CdÀCl(1), 88.75(11) ( Figure S40; Table S7). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 Figure S43).…”

“…A self-assembled dimer of sym-1,3,5trisubstituted six-membered aromatic rings can be seen as a sym-hexasubstituted benzene molecule. [16] Symmetrically trisubstituted molecules and PPs are of tremendous interest in the context of materials for nonlinear optics, [5][6][7][8][9][10][11][12][17][18][19][20][21][22] constructing porous materials, [23][24][25][26][27][28][29][30][31][32][33][34][35][36] building blocks for nano-scalar supramolecules, [37][38][39][40][41][42][43] self-assembling metallacycles, [44][45][46][47][48][49][50][51][52][53][54][55][56] encapsulation ...…”

“…A self‐assembled dimer of sym ‐1,3,5‐trisubstituted six‐membered aromatic rings can be seen as a sym ‐hexasubstituted benzene molecule . Symmetrically trisubstituted molecules and PPs are of tremendous interest in the context of materials for nonlinear optics,, constructing porous materials, building blocks for nano‐scalar supramolecules, self‐assembling metallacycles, encapsulation of guests, etc., The PPs reported by Czugler et al., exhibited supramolecular assemblies that resemble ‘BigMac’ where solvent molecules such as dimethylformamide, ethanol, acetone, water and acetic acid were encapsulated between two PPs; two PPs have been compared to two buns and solvent molecules were compared to the patty …”