Two new isomeric dinitrile ligands containing imidazolium salt cores have been synthesized from cyanoanilines in good yield. These have been converted to the corresponding dicarboxylic acids using hydrobromic acid, or the dicarboxylic acids were synthesized directly from the analogous cyanoaniline starting material in a two-step, one-pot reaction. The crystal structures of three of the four compounds are reported. Two reaction pathways with metals are possible for the dicarboxylic acids, initially giving rise to metal carboxylate based metal-organic frameworks (MOFs) as described in this work or N-heterocyclic carbene (NHC) metal complexes en route to the synthesis of MOFs containing tethered NHC complexes. The reaction of 1,3-bis(4-carboxyphenyl)imidazolium bromide with zinc nitrate in dimethylformamide (DMF) gave a one-dimensional (1D) MOF containing the intact imidazolium salt. The potentially porous structure, formed from close packing of the 1D necklace-type polymers, contains channels occupied by disordered DMF solvate molecules. A formate anion also bridges the zinc secondary building units in the 1D polymer, which has an undulating structure resulting from the U-shaped conformation of the dicarboxylate imidazolium ligand.

A new MOF, [Zn4O{Cu(L)2}2], with 14 Å channels lined by in situ generated [Cu(L)2] N-heterocyclic carbene linkers catalyses the hydroboration of CO2.

Azolium and metalated N-heterocyclic carbene (NHC) functionalised metal-organic frameworks (MOFs) have been investigated as adsorbents and heterogenous catalysts. Here we describe the structures of two sets of 1D polymeric structures, {[M 2 (μ 2 -HCOO)(HL) 2 ](NO 3 )•xDMF} n (M = Zn, x = 1, 1; Cu, x = 1.75, 2) and {[M 3 (HL) 4 (H 2 O) 4 ](NO 3 ) 2 •xDMF} n (M = Co, x = 2.75, 3; Mg, x = 0, 4; Mn, x = 1.5, 5), prepared from reactions of 1,3-bis(3-carboxyphenyl)-1H-imidazol-3-ium bromide (H 3 LBr) with M(NO 3 ) 2 •xH 2 O (M = Zn, Cu, Co and Mg)and MnCl 2 •4H 2 O. These pack as porous and non-porous 3D materials, respectively. In the case of the known Zn(II) material 1, which we reveal to be porous, we also report metalation of the NHC precursor concomitant with framework synthesis to give {[Zn 2 (μ 2 -HCOO)(HL) 1.6 (L-Cu-Br) 0.4 ](NO 3 ) 0.6 •0.75DMF} n (1-Cu). Compounds 1, 2, and 1-Cu show H 2 adsorption enthalpies of −9.9, −9.1, and −9.7 kJ mol −1 respectively, and allow the effect of micropores decorated with charged imidazolium moieties, or NHC-CuBr entities, on H 2 adsorption to be probed.

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