H-bonded adducts of [2,4,6-{(C₁₀H₂₁O)₃C₆H₂NH}₃C₃N₃] with [LnM{PPh₂(C₆H₄CO₂H)}] displaying Columnar Mesophases at Room Temperature

Abstract

Displacement of a labile ligand from appropriate precursor complexes by 2- or 4-PPh2C6H4COOH yields neutral gold(I) and gold(III) [AuXn(PPh2C6H4COOH)] (n = 1, X = Cl; n = 3, X = C6F5), cationic gold(I) [Au(PPh2C6H4COOH)2](CF3SO3), and neutral chromium(0) [Cr(CO)5(PPh2C6H4COOH)] metallo-organic acids. [AuCl(4-PPh2C6H4COOH)], [Au(C6F5)3(4-PPh2C6H4COOH)], and [Cr(CO)5(2-PPh2C6H4COOH)] have dimeric structures with typical carboxylic H-bond bridges, whereas [Au(C6F5)3(2-PPh2C6H4COOH)] gives a monomeric species with the carboxylic acid H bonded to cocrystallized solvent molecules. All gold-containing acids are emissive at 77 K in the range 404-520 nm and some of them also at 298 K with emission maxima from 441 to 485 nm. Reaction of these acid metal complexes with the triazine mesogen 2,4,6-{(C10H21O)3C6H2NH}3C3N3 affords some new hydrogen-bonded gold(I) and chromium(0) supramolecular adducts, but the related gold(III) complexes do not form adducts. The 4-diphenylphosphinobenzoic adducts display a columnar hexagonal mesophase (Colhex) at room temperature, with a random one-dimensional stacking of the pseudo-discoid triazine-metallo-organic adducts into columns, where the metallo-phosphinoacid fragments act as the fourth branch of the trifold triazine core. The 2-diphenylphosphinobenzoic mixtures do not display mesophases, as they appear in the X-ray studies as mixtures of the triazine and the metallo-phosphinoacid complex. The aggregates are luminescent at 77 K, with emission maxima in the range 419-455 nm.

Star-shaped triphenylene discotic liquid crystalline oligomers and their hydrogen-bonded supramolecular complexes with simple acids

“…Furthermore, complexity and diversity can be easily added by introducing additional functionalities within the supramolecular architecture by using complementary acids bearing redox-active units, dyes, radicals or metallic fragments. 51,58 Experimental section…”

“…57 Furthermore, the sigma-bonded tris(triazolyl)benzene central core is not that favorable to mesomorphism, as it is not planar and excludes the possibility for strong p-p interactions. 51,58 This fragment is however a good hydrogen-bonding acceptor, 32 which can react with carboxylic acids and form flat supramolecular complexes, since the H-bonds will pull the triazole rings back to the benzene plane. Hence, additional p-p interactions might appear and foster columnar mesomorphism.…”

Polymorphism of hydrogen-bonded star mesogens – a combinatorial DFT-D and FT-IR spectroscopy study

“…[22][23][24][25][26][27] Within the past two decades seminal works by Kato, Fréchet, Lehn and Percec [7][8][9][28][29][30][31][32][33][34][35][36][37] have demonstrated that selfassembled LCs have a broad application potential in scientic and technological elds due to mimicking the efficient selfassembly process of nature. [38][39][40][41][42][43][44][45] In contrast to their covalent pendants, supramolecular star mesogens are more exible and may show more complex mesostructures (see for instance Fig. 1B).…”

A trigonal coordination of Au(I) phosphane complexes stabilized by O–H⋯X (X = Cl–, Br–, I–) interactions

“…Reaction of 2-(diphenylphosphino)benzoic acid, Ph 2 (o-BzOH)P, with equimolar amounts of (tht)AuCl (tht = tetrahydrothiophene) leads to the formation of 2-(diphenylphosphino)benzoic acid gold(I) chloride, Ph 2 (o-BzOH)PAuCl, 1-Cl. It should be mentioned that various gold(I) complexes bearing a diphenylphosphino-benzoic acid-both ortho and para-have been reported, among them also 1-Cl [56][57][58][59]. Through metathesis with KBr and KI the bromido and iodido congener 1-Br and 1-I are easily accessible.…”