The NF material RM734 was synthesised according to the original report by Mandle et al. The precursor carboxylic acid, 4-nitropyridine 25 and 3-fluoro-4-nitropyridine were synthesised according to precedent. Repeated attempts to form the target hydrogen bonded complexes (Fig. ) using commercially sourced 4-nitropyridines were met with failure; we attribute this to varying (and typically high) degrees of autoxidation to the N-oxide derivative. Synthesised 4-nitropyridines were stored under nitrogen at -20 °C and were used within 6 hours of synthesis. The hydrogen-bonded complexes were prepared as shown in scheme 1: the carboxylic acid (1 mmol) was suspended in acetone (3.5 ml) in a 7 ml vial, and vigorously stirred under an atmosphere of nitrogen gas. The suspension was partially dissolved by heating to 50 °C, before adding a solution of the pyridine derivative (1 mmol) in acetone (0.5 ml), prompting a slight exotherm and affording a near homogenous solution. The solution was stirred for 1 h at 50 °C before cooling to ambient temperature.