Crystal structure and electrical conductivity of {trans-[Ru(ox)(en)2NO]}2(TCNQ)3 (ox=oxalate, en=ethylenediamine, TCNQ=7,7,8,8-tetracyanoquinodimethane) at ground state

The radical anion salt of TCNQ (7,7,8,8-tetracyanoquinodimethane) with the trans-[Ru(ox)(en)2NO]+ cation (ox=oxalate, en=ethylenediamine), namely {trans-[Ru(ox)(en)2NO]}2(TCNQ)3, was synthesized by slow diffusion method from water solution of trans-[Ru(ox)(en)2NO]Cl and of LiTCNQ. An X-ray structure analysis indicates that the cation: anion ratio of the obtained complex is 2:3. Two of three TCNQ molecules are stacked along the a direction to form columnar structure. Between these columns the remaining TCNQ molecules are inserted with their long molecular axis along a direction. Several -N⋯HN- type hydrogen bonds between nitrile groups of TCNQ molecules and ethylenediamine ligands of trans-[Ru(ox)(en)2NO]+ cation, and -O⋯HN- type hydrogen bonds between oxygen atoms of oxalate ligands of trans-[Ru(ox)(en)2NO]+ cations and ethylenediamine ligands of neighboring trans-[Ru(ox)(en)2NO]+ cations are observed. The room temperature electrical conductivity of {trans-[Ru(ox)(en)2NO]}2(TCNQ)3 is <10−6 S cm−1.