Synthesis and electrical resistivity of tetrakis(isocyanide)rhodium(I) cation-TCNQ radical anion salts

Abstract

The following 12 simple and complex salts of the TXNQ⨪ radical anion with tetrakis(alkyl- or arylisocyanide)rhodium(I) cations were prepared; [Rh(RNC) 4] +TCNQ⨪ (R =t-Bu, c-C 6H 11, 4-MeC 6H 4, 4-MeOC 6H 4, 2,6,Me 2C 6H 3 and 2,4,6-Me 3C 6H 2), [Rh(RNC) 4] +(TCNQ⨪ 2 (R = c-c 6H 11, Ph, 4-MeC 6H 4, 2,6-Me 2C 6H 3, and 2,4,6-Me 3C 6H 2) and [Rh(4-MeC 6H 4NC) 4 +(TCNQ⨪ 3. In addition, a novel TCNQ⨪ salt formulated as [Rh(PhNC) 4] +(TCNQ⨪) 2 3 )(cLo − 4) 1/3 also was obtained. Electrical resistivities of the simple salts vary widely over the 3.0 × 10 5 - larger than 10 10 Ω cm range as compacted samples at 25 °C. The variation of resistivities over a wide range was found also in the 1:2 complex salts, of which [Rh(PhNC) 4] + (TCNQ⨪ 2 and [Rh(4-MeC 6H 4NX) 4 + (TCNQ⨪ 2 exhibit relatively small resistivities, 9.3 and 38 Ω cm, respectively. as compacted samples at 25 °c. Electronic absorption spectra and magnetic susceptibilities of the salts are discussed in terms of the stacking of the TCNQ⨪ radical anion (and also neutral TCNQ for the complex salts) in the crystalline state