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

• Published in: Inorganic chemistry Vol. 53; no. 20; pp. 10893 - 10902
• Main Authors: Miguel-Coello, Ana B, Bardají, Manuel, Coco, Silverio, Donnio, Bertrand, Heinrich, Benoît, Espinet, Pablo
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 20-10-2014
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic501039n

Displacement of a labile ligand from appropriate precursor complexes by 2- or 4-PPh2C6H4COOH yields neutral gold(I) and gold(III) [AuX n (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.