A new indium metal-organic 3D framework with 1,3,5-benzenetricarboxylate, MIL-96 (In), containing μ3-oxo-centered trinuclear units and a hexagonal 18-ring network

Abstract

A new indium trimesate In 12O(OH) 12({OH} 4,{H 2O} 5)[btc] 6·≈31H 2O, called MIL-96, (btc = 1,3,5-benzenetricarboxylate or trimesate species) was hydrothermally synthesized under mild condition (210 °C, 5 h) in the presence of trimethyl 1,3,5-benzenetricarboxylate in water and characterized by single-crystal X-ray diffraction technique. The MIL-96 (In) structure exhibits a three-dimensional metal-organic framework containing isolated trinuclear μ 3-oxo-bridged indium clusters and infinite chains of InO 4(OH) 2 and InO 2(OH) 3(H 2O) octahedra generating a hexagonal network based on 18-membered ring. The two types of indium entities are connected to each other through the trimesate species which induce corrugated chains of indium octahedra, linked via μ 2-hydroxo bonds with the specific – cis–cis–trans– sequence. The 3D framework of MIL-96 reveals three kind of cavities (two of them have estimated ≈ 400 Å 3 volumes), in which are encapsulated free water molecules. The latter species are removed upon heating at 150 °C.