Reaction of Octachlorodirhenate with a Redox-Active Tetrathiafulvalene Phosphine Ligand:  Spectroscopic, Magnetic, and Structural Characterization of the Unusual Paramagnetic Salt [ReCl₂(o-P2)₂][Re₂Cl₆(o-P2)] (o-P2 =o-{P(C₆H₅)₂}₂(CH₃)₂TTF)

Abstract

Reaction of [(n-Bu)(4)N](2)[Re(2)Cl(8)] with the tetrathiafulvalene phosphine ligand o-{P(C(6)H(5))(2)}(2)(CH(3))(2)TTF (o-P2) in refluxing ethanol produces the mixed-nuclearity salt [ReCl(2)(o-P2)(2)][Re(2)Cl(6)(o-P2)] (1.2), composed of the mononuclear Re(III) complex (1) and the mixed-valence Re(II)-Re(III) dinuclear anion (2). The complex crystallizes as a CH(2)Cl(2) solvate in the triclinic space group P&onemacr;, a = 13.4559(1) Å, b = 20.4015(3) Å, c = 21.5538(1) Å, alpha = 88.261(1) degrees, beta = 72.987(1) degrees, gamma = 84.933(1) degrees, and Z = 2. The molecular cation consists of two trans o-P2 ligands in the equatorial plane and axial chloride ligands. The dinuclear anion adopts an eclipsed geometry with an unsymmetrical coordination environment for the two metal atoms; one Re(II) center is coordinated to a chelating o-P2 ligand and two chlorides while the other Re atom is coordinated to four chloride ligands. The dinuclear portion of the salt is a monoanion which leads to a formal bond order assignment of 3.5, based on the fact that the molecule possesses an Re(2)(5+) core. The salt was further characterized by infrared and electronic spectroscopies, electrochemistry, and variable temperature magnetic susceptibility; the presence of the individual ions in bulk samples was verified by positive and negative FAB mass spectrometry. Isolation of the two separate ions was achieved by treatment of the salt with Co(C(5)H(5))(2), which reduces the Re(III) cation to the Re(II) complex ReCl(2)(o-P2)(2) (3). This neutral compound was separated from the byproduct salt [Co(C(5)H(5))(2)][Re(2)Cl(6)(o-P2)] and reoxidized with CCl(4)/CH(2)Cl(2) or NOBF(4) to produce [ReCl(2)(o-P2)(2)][Cl] (1.[Cl]) and [ReCl(2)(o-P2)(2)][BF(4)] (1.[BF(4)]), respectively. Compounds 3, 1.[Cl], and 1.[BF(4)] were identified by a combination of infrared spectroscopy, mass spectrometry, and cyclic voltammetric measurements. Variable temperature dc susceptibility studies of [ReCl(2)(o-P2)(2)][Re(2)Cl(6)(o-P2)] (1.2) revealed classical Curie paramagnetic behavior (with a Curie constant equal to 0.395) and a large temperature independent paramagnetic contribution (chi(TIP) = 9.64 x 10(-)(3) emu/mol). The EPR spectrum of 1.2 consists of a broad, complex signal due to hyperfine interactions to both isotopes (185,187)Re (I = (5)/(2)) and (31)P (I = (1)/(2)) which is typical for paramagnetic metal-metal bonded dirhenium phosphine compounds.

Ligands Derived from Tetrathiafulvalene: Building Blocks for Multifunctional Materials

“…Similar redox reactivity in the reaction with dm-TTFdpp 2 was observed for (TBA) 2 [Re 2 Cl 8 ], which was converted to {[Re III Cl 2 (dm-TTFdpp 2 ) 2 ][Re 2 II/III Cl 6 (dm-TTFdpp 2 )]}. 81 The latter is composed of a mononuclear cationic complex and a dinuclear mixed-valent anionic complex (Fig. 15).…”

Tetrathiafulvalene–phosphine-based iron and ruthenium carbonyl complexes: Electrochemical and EPR studies

“…Indeed, much larger folding angles, up to about 251, along PÁ Á ÁP or SÁ Á ÁS hinges were observed for different P2 complexes. 11,12,34 An ORTEP representation of the complex is shown in Fig. 1. …”

Tetrathiafulvalene-based group XV ligands: Synthesis, coordination chemistry and radical cation salts

“…As demonstrated by X-ray analysis(Fig. 12), the cation of this complex salt consists of a bis(chelated) [Re(III)Cl 2 ] + fragment, while the anion contains a mixed valence Re(II)-Re(III) species formulated as [(104)ReCl 2 ReCl 4 ] −[98].…”

“…Crystalline structure of the cation (left) and anion (right) of the complex salt Re3[98].As for the Mo and W complexes with 104 and 103 (see Section 3.1), large anodic shifts, when compared to the uncoordinated ligands, are observed in cyclic voltammetry of both Re1 and Re2, especially for the first oxidation processes, i.e. 0.25 V (Re1) and 0.49 V (Re2).A peculiar Re-based complex (Re3) has been serendipitously obtained in the reaction between the ligand 104 and the Re(III) salt [(n-Bu)4 N] 2 [Re 2 Cl 8 ].…”