Supramolecular Assemblies Involving Organometallic Free Acids

Abstract

Reactions between W(η2-Ph2C2)Cl4 and salicylic acid derivatives generate analytically pure free acids of formula W(η2-Ph2C2)Cl3(Hsal-R) (1) in high yields (Hsal = a salicylate monoanion). The products exist as hydrogen-bonded dimers in the solid state. The acid functionality on one molecule hydrogen bonds to one of the cis-chloride ligands of an adjacent complex at a 3.03 Å distance. The more electron-rich tungsten center renders these acetylene complexes less acidic than their oxo and arylimido analogs. As a result, W(η2-Ph2C2)Cl3(Hsal) exhibits partial dimerization in solution and have relatively weak hydrogen bonds to nitrogen- and oxygen-containing organic molecules. Among a range of possible phenol−phenoxide complexes of the W(η2-Ph2C2)Cl3 subunit, only the ether adduct of the catecholate, W(η2-Ph2C2)Cl3(Hcat···OEt2) (2), has been isolated and structurally characterized. The weaker hydrogen bond strength of larger chelating bis(phenolates) evidently destabilize the phenol−phenoxide structures in favor of simple chelating bis(phenoxides). The salicylate free acids form various supramolecular complexes in solution and the solid state, including [W(η2-Ph2C2)Cl3(Hsal)]4(18-crown-6) (5), one of a family of tetranuclear systems organized around hydrogen bonding to an 18-crown-6 template. This structure is characterized by π-stacking of the Hsal ligands between confacial free acid complexes and the steric screening of the two non-hydrogen-bonded 18-crown-6 oxygens by pairs of antarafacial W(Ph2C2) units.

Bis[N-(8-quinolyl)pyridine-2-carboxamidato]iron(III) perchlorate monohydrate

“…Thus far, N-containing aromatic carbonyl amines have been widely used in dye intermediates, organic synthesis, sensitization materials, functional pigments, adipiodone and acetrizoic acid (An et al, 2000). Pyridine carbonyl amine is also a good ligand in coordination chemistry due to its strong coordination ability and versatile coordination modes, so much attention has been paid to it in recent years (Baroni et al, 1996;Hundal et al, 2002). Here we report the new title complex.…”

“…For related literature, see: Li et al (1993); Go et al 2004; An et al (2000); Baroni et al (1996); Hundal et al (2002).…”

Poly[[aqua(2,2′-bipyridine)(μ3-pyridine-3,4-dicarboxylato)nickel(II)] monohydrate]

“…Thus far, N-containing aromatic carboxylic acids have been widely used in dye intermediates, organic synthesis, sensitization materials, functional pigments, adipiodone and acetrizoic acid (An et al, 2000). Pyridinecarboxylic acids are also good ligands in coordination chemistry due to their strong coordination ability and versatile coordination modes, so much attention has been paid to them in recent decades (Baroni et al, 1996;Hundal et al, 2002). Here we report the new title nickel complex.…”

“…For related literature, see: An et al 2000; Baroni et al (1996); Go et al 2004; Hundal et al (2002); Li et al (1993). Symmetry codes: (i) x; Ày þ 1 2 ; z À 1 2 ; (ii) Àx þ 1 2 ; y À 1 2 ; z; (iii) Àx þ 1 2 ; y À 1 2 ; z þ 1; (iv) x; Ày þ 1 2 ; z þ 1 2 .…”

Synthesis, crystal structure and magnetic properties of a new 1D cobalt(II) complex with 1,10-phenanthroline and 3,5-dinitrosalicylate acid ligands

“…In contrast to aromatic dicarboxylate compounds, the presence of the hydroxyl group in salicylic acid ligand allows the formation of six-membered rings which can stabilize the solid networks. Metal-organic frameworks with salicylic acid ligand and nitrogen-containing ligands were found to display multipoint diverse structure types such as discrete clusters [11][12][13][14][15][16][17][18][19][20][21] and onedimensional (1D) chain compounds [22][23][24]. However, substituted salicylic acid such as 3,5-dinitrosalicylic acid ligand [25] is much less applied compared with salicylic acid ligand [26][27][28][29][30][31][32][33][34].…”