Thermodynamic, Physical, and Structural Characteristics in Layered Hybrid Type (C2H5NH3)2MCl4 (M = 59Co, 63Cu, 65Zn, and 113Cd) Crystals.

Ae Ran Lim

doi:10.3390/molecules25081812

Abstract

The thermal, physical, and molecular dynamics of layered hybrid type (C2H5NH3)2MCl4 (M = 59Co, 63Cu, 65Zn, and 113Cd) crystals were investigated by thermogravimetric analysis (TGA) and magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The temperatures of the onset of partial thermal decomposition were found to depend on the identity of M. In addition, the Bloembergen–Purcell–Pound curves for the 1H spin-lattice relaxation time T1ρ in the rotating frames of CH3CH2 and NH3, and for the 13C T1ρ of CH3 and CH2 were shown to exhibit minima as a function of the inverse temperature. These results confirmed the rotational motion of 1H and 13C in the C2H5NH3 cation. Finally, the T1ρ values and activation energies Ea obtained from the 1H measurements for the H‒Cl···M (M = Zn and Cd) bond in the absence of paramagnetic ions were larger than those obtained for the H‒Cl···M (M = Co and Cu) bond in the presence of paramagnetic ions. Moreover, the Ea value for 13C, which is distant from the M ions, was found to decrease upon increasing the mass of the M ion, unlike in the case of the Ea values for 1H.

Highlights

Layered hybrid compounds have drawn great attention as a new generation of high performance materials due to their interesting physical and chemical properties obtained through the combination of organic and inorganic materials at the molecular level [1,2,3]
Upon comparison of the thermogravimetric analysis (TGA) results with the possible chemical reactions taking place, the solid residues formed for (C2 H5 NH3 )2 MCl4 were calculated based on Equations (1)–(4) [28]: (C2 H5 NH3 )2 CoCl4 → (C2 H5 NH2 )2 CoCl2 (s) + 2HCl (g)
The 1 H magic angle spinning nuclear magnetic resonance (MAS nuclear magnetic resonance (NMR)) and 13 C CP/magic angle spinning (MAS) NMR spectra for the rotating frame of (C2 H5 NH3 )2 MCl4 were measured at the Larmor frequencies of 400.13 and 100.61 MHz, respectively, using a Bruker

Summary

Introduction

Layered hybrid compounds have drawn great attention as a new generation of high performance materials due to their interesting physical and chemical properties obtained through the combination of organic and inorganic materials at the molecular level [1,2,3] They consist of a wide range of inorganic anion chains, alternating with a large variety of organic cations as building blocks. The organic component of the hybrid complex provides several useful properties, such as structural flexibility and optical properties, while the inorganic part is responsible for the mechanical and thermal stabilities, in addition to interesting magnetic and dielectric transitions [4,5] The diversity of such hybrid materials is large, and so offers a wide range of structures, properties, and potential applications [6,7,8,9,10,11].

Methods

Results

Conclusion