Coordination bond formation at charge-transfer phase transition in (BDTA)2[Co(mnt)2].

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• Charge-transfer salts exhibit unique electronic and magnetic properties.
• The structure of (BDTA)2[Co(mnt)2] involves alternating columns of BDTA+ dimers and [Co(mnt)2]2- anions.
• Understanding phase transitions in such materials is crucial for their potential applications.

Purpose of the Study:

• To elucidate the crystal structure of the charge-transfer salt (BDTA)2[Co(mnt)2].
• To investigate the magnetic properties and identify any phase transitions.
• To characterize the structural and electronic changes occurring during the phase transition.

Main Methods:

• Single-crystal X-ray diffraction at 253 K to determine the initial crystal structure.
• Magnetic susceptibility measurements to probe electronic behavior and phase transitions.
• Structural analysis to correlate magnetic changes with atomic rearrangements.

Main Results:

• The crystal structure at 253 K revealed an alternating stacking of head-to-head BDTA+ dimers and planar [Co(mnt)2]2- dianions.
• A phase transition was identified at 190 K through magnetic and structural analyses.
• The transition involves partial electron transfer from [Co(mnt)2]2- to a BDTA+ cation, leading to coordination bond formation.

Conclusions:

• The charge-transfer salt (BDTA)2[Co(mnt)2] exhibits a temperature-dependent phase transition.
• This transition is characterized by significant electronic redistribution and the formation of new coordination bonds.
• The findings provide insights into the structure-property relationships in organic-inorganic hybrid charge-transfer materials.