Vanadium O-Centered Selenoiodide Complex: Synthesis and Structure of V4O(Se2)4I6•I2

The first vanadium selenoiodide V4O(Se-2)(4)I-6 center dot I-2 was synthesized at a moderate temperature of 220 degrees C from V, Se, I-2, and water. Its crystal structure (tetragonal space group P4(2)/nbc, a = 11.838(1) angstrom, c = 18.689(1) angstrom) contains O-centered vanadium-(IV) tetranuclear fragment [V-4(mu(4)-O)(mu(2)-Se-2)(4)(mu(2)-I)(2)I-4], where the edges of the distorted tetrahedron V-4 are bridged by four diselenide (Se-2)(2-) and two iodide ligands; four terminal iodides coordinate V atoms additionally. This type of complex is known for Ti, Nb, and Ta but is new for vanadium. Magnetic susceptibility measurements of V4O(Se-2)(4)I-6 center dot I-2 showed four unpaired electrons on vanadium atoms at room temperature and drop of the effective magnetic moment at cool down, presumably due to partial electron pairing. Probability of this transition to the diamagnetic state is in accord with the calculated electronic structure.

Automated summary

The first vanadium selenoiodide V4O(Se-2)(4)I-6•I-2 was synthesized at 220 degrees C from V, Se, I-2, and water. Its crystal structure contains a unique arrangement of V, Se, O, and I atoms. The compound shows four unpaired electrons on vanadium at room temperature and a reduction in effective magnetic moment upon cooling, suggesting partial electron pairing. The probability of transitioning to the diamagnetic state aligns with the calculated electronic structure.