Anion Conformation and Physical Properties in BETS Salts with the Nitroprusside Anion and its Related Ruthenium Halide (X = Cl, Br) Mononitrosyl Complexes: θ-(BETS)4[Fe(CN)5NO], (BETS)2[RuBr5NO], and (BETS)2[RuCl5NO]

Abstract

θ-(BETS) 4 [Fe(CN) 5 NO] (1), (BETS) 2 [RuBr 5 NO] (2), and (BETS) 2 [RuCl 5 NO] (3) [BETS = bis(ethylenedithio)tetraselenafulvalene] have been prepared by electrocrystallisation of BETS using [Fe(CN) 5 NO] 2− or [RuX 5 NO] 2− , X = Cl or Br, as supporting electrolytes and 1,1,2-TCE/ethanol (10 vol%) for 1, nitrobenzene/1,2-DCE (40 vol%)/ethanol (10 vol%) for 2, and benzonitrile/ethanol (10%) solutions for 3 as solvents.Compound 1 exhibits a metallic behaviour down to 40 K, 2 behaves as a semiconductor and 3 as an insulator. The crystal

Electrical and optical properties of (PPh4)2[Fe(CN)5NO] non-crystalline thin films prepared with the vacuum thermal evaporation technique

“…C"N 1À is a strong p-acceptor ligand, so that the metallic-like molecular orbitals of a [Fe(CN) 5 NO] 2À pseudo-octahedron are expected to be less occupied for an equivalent NO bending angle. Hence, to stabilize an Fe II formal oxidation state, the anions of C 43 H 28 N 6 O 5 PFeK would require a larger electron density from the 1,8-dihydroxyanthraquinone layers, in agreement with the stoichiometry observed for that compound in (BETS) 4 [-Fe(CN)5NO] [11]. Since no accurate information on the anionic layers is available, the electronic transfer cannot be accurately determined here.…”

“…The C 43 H 28 N 6 O 5 PFeK and C 43 H 29 N 6 O 5 PFe thin films showed lower electrical conductivities than those reported for molecular materials having the nitroprusside anion [4,11]. Thus, the (BETS) 4 [-Fe(CN) 5 NO] thin film deposited on a (100) intrinsic-Si substrate had a room-temperature conductivity of 1.6 S-cm À1 .…”

“…This novel class of multifunctional materials should provide a unique opportunity to study the competition and mutual influence of two properties in the same material and, even better, a possible interplay between them as well. A parallel approach involving the use of conducting radical cation salts with photochromic anions has been recently explored [11]. One goal in the synthesis and characterization of new molecular conductors containing photochromic anions is to analyze the influence of the electronic excitations of the anions on the conducting electrons [11].…”

“…A parallel approach involving the use of conducting radical cation salts with photochromic anions has been recently explored [11]. One goal in the synthesis and characterization of new molecular conductors containing photochromic anions is to analyze the influence of the electronic excitations of the anions on the conducting electrons [11]. The preparation of these materials as thin films is of considerable interest for eventual device applications.…”

“…These anions are very interesting because they possess extremely long-lived metastable excited states at low temperatures that can be generated by laser irradiation [11]. [Fe(CN) 5 NO] 2À is of interest not only in connection with its various structural motifs, but also regarding its magneto-optical properties [12].…”