Temperature dependence of one-dimensional hydrogen bonding in morpholinium hydrogen chloranilate studied by 35Cl nuclear quadrupole resonance and multi-temperature X-ray diffraction†
Abstract
The temperature dependence of 35Cl NQR frequencies and the spin–lattice relaxation times T1 has been measured in the wide temperature range of 4.2–420 K for morpholinium hydrogen chloranilate in which a one-dimensional O–H⋯O hydrogen-bonded molecular chain of hydrogen chloranilate ions is formed. An anomalous temperature dependence of the NQR frequencies was analyzed to deduce a drastic temperature variation of the electronic state of the hydrogen-bonded molecular chain. The hydrogen atom distribution in the O⋯H⋯O hydrogen bond is discussed from the results of NQR as well as multi-temperature