Crystal Chemistry, Optic and Magnetic Characterizations of a New Copper Based Material Templated by Hexahydrodiazepine

Abstract

Crystals of the new organic−inorganic material (DAP-H2)[CuBr 4 ] (1); (DAP = hexahydrodiazepine (C 5 H 14 N 2 )) were successfully synthesized by slow evaporation and characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermal analysis, UV−Vis−NIR diffuse reflectance spectroscopy, and magnetic measurements. X-ray investigation demonstrates that 1 crystallizes in the monoclinic space group C2/c. The supramolecular crystal structure of 1 is guided by several types of hydrogen bonding which connect anions and cations together into a three-dimensional network. The optical band gap was determined by diffuse reflectance spectroscopy to be 1.78 eV for a direct allowed transition, implying that it is suitable for light harvesting in solar cells. The vibrational properties of this compound were studied by infrared spectroscopy, while its thermal stability was established by simultaneous TGA−DTA from ambient temperature to 600 °C. The study of the photoresponse behavior of an optoelectronic device, based on (C 5 H 14 N 2 )[CuBr 4 ], has shown a power conversion efficiency (PCE) of 0.0017%, with J sc = 0.0208 mA/cm 2 , V oc = 313.7 mV, and FF = 25.46. Temperature dependent magnetic susceptibility measurements in the temperature range 1.8−310 K reveal weak antiferromagnetic interactions via the two-halide superexchange pathway [2J/k B = −8.4(3) K].