1,2,4-Triazole functionalized adamantanes: a new library of polydentate tectons for designing structures of coordination polymers

Abstract

A series of functionalized adamantanes: 1,3-bis(1,2,4-triazol-4-yl)(tr₂ad); 1,3,5-tris(1,2,4-triazol-4-yl)-(tr₃ad); 1,3,5,7-tetrakis(1,2,4-triazol-4-yl)adamantanes (tr₄ad) and 3,5,7-tris(1,2,4-triazol-4-yl)-1-azaadamantane (tr₃ada) were developed as a new family of geometrically rigid polydentate tectons for supramolecular synthesis of framework solids. The coordination compounds were prepared under hydrothermal conditions; their structures reveal a special potential of the triazolyl adamantanes for the generation of highly-connected and open frameworks as well as structures based upon polynuclear metal clusters assembled with short-distance N₁,N₂-triazole bridges. Complexes [Cd{L}₂]A·nH₂O [L = tr₃ad, A = 2NO₃⁻ (4), CdCl₄²⁻ (5); L = tr₃ada, A = CdI₄²⁻ (7)] are isomorphous and adopt a layered 3,6-connected structure of CdI₂ type. [{Cu₃(OH)}₂(SO₄)₅(H₂O)₂{tr₃ad}₃]·26H₂O (6) is a layered polymer based upon Cu₃(μ₃-OH) nodes and trigonal tr₃ad links. In [Cu₃(OH)₂{tr₃ada}₂(H₂O)₄](ClO₄)₄ (8), [Cu₂{tr₃ada}₂(H₂O)₃](SO₄)₂·7H₂O (9) and [Cd₂{tr₃ada}₃]Cl₄·28H₂O (10) (UCl₃-type net) the organic tripodal ligands bridge polynuclear metal clusters. Complexes [Ag{tr₄ad}]NO₃·3.5H₂O (11) and [Cu{tr₄ad}(H₂O)](ClO₄)₂·3H₂O (12) have 3D SrAl₂-type frameworks with the metal ions and adamantane tectons as topologically equivalent tetrahedral nodes, while in [Cd₃Cl₆{tr₄ad}₂]·9H₂O (13) the ligands bridge trinuclear six-connected Cd₃Cl₆(μ-tr)₄(tr)₂ clusters. In the compounds [Cd₂{tr₂ad}₄(H₂O)₄](CdBr₄)₂·2H₂O (2) and [Cd{tr₂ad}₄{CdI₃}₂]·4H₂O (3) the bitopic ligands provide simple links between the metal ions, while in [Ag₂{tr₂ad}₂](NO₃)₂·2H₂O (1) the ligand is tetradentate and generates a 3D framework.