Triazolium-Containing Metal-Organic Frameworks: Control of Catenation in 2D Copper(II) Paddlewheel Structures

One approach to exploit metal-organic frameworks (MOFs) as heterogeneous catalyst platforms requires the development of materials containing groups that can be utilised to anchor a catalytic moiety into the links within the structure. Here we report the synthesis of the first integrated triazolium-containing MOF linker and the first MOFs containing linkers of this type. 1,4-Bis(4-benzoic acid)-1-methyl-1H-1,2,3-triazolium chloride, H(2)L1(Me), was synthesised in three steps by a 'click' reaction of methyl 4-ethynylbenzoate with methyl 4-azidobenzoate, methylation using methyl triflate, followed by ester hydrolysis in overall 74% yield. The equivalent neutral triazole precursor, 1,4-bis(4-benzoic acid)-1H-1,2,3-triazole hydrochloride, H(2)L1(HCl), was also prepared and a comparison of the chemistry with Zn(NO3)(2)center dot 6H(2)O and Cu(NO3)(2)center dot 3H(2)O is presented. The results support the use of reaction conditions to control interpenetration and provide additional evidence that the charge on structurally similar ligands can drastically alter the types of structures that are accessible due to the requirements for charge balance in the final product.