No 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.

Reactions of 3,4-dimethyl-3',4'-bis(diphenylphosphino)tetrathiafulvalene, o-P2, with [BF(4)](-) salts of Fe(ii), Co(ii), Ni(II), Pd(II), and Pt(II) yield complexes of general formula [M(o-P2)(2)][BF(4)](2). Similar reactions between o-P2 and AgSbF(6) or AgPF(6) produced the salts [Ag(o-P2)(2)][X] where X = [SbF(6)](-) or [PF(6)](-). The resulting compounds were fully characterized by (1)H and (31)P{(1)H} NMR, infrared and electronic absorption spectroscopies, cyclic voltammetry, FAB-MS and single-crystal X-ray diffraction. The paramagnetic Co(II) compound exhibits an S = 3/2 state with large spin-orbit coupling contribution at higher temperatures and an effective S' = 1/2 state below 20 K. Electrochemical studies of the compounds indicate that the two functionalized TTF ligands are not in electronic communication and that they essentially behave as isolated redox centers.

A series of new complexes incorporating the functionalized tetrathiafulvalene (TTF) ligands ortho-(CH 3 ) 2 (P(C 6 H 5 ) 2 ) 2 -TTF (o-P2) and (P(C 6 H 5 ) 2 ) 4 TTF (P4) have been prepared and studied by fast atom bombardment mass spectrometry (FABMS). The mononuclear o-P2 complexes [M(o-P2) 2 ](BF 4 ) 2 (M ) Fe, Pd, Pt) and [Co(o-P2) 2 (NCCH 3 ) 2 ](BF 4 ) 2 were synthesized from reactions of the free ligand with the fully solvated BF, was produced by reacting the free ligand with PtCl 2 (NC 7 H 5 ) 2 followed by abstraction of the chlorides with AgBF 4 in acetonitrile.Reaction of [Pd(NCCH 3 )](BF 4 ) 2 with 1 equiv of P4 produces the polynuclear compound formulated as [Pd(P4)] n (BF 4 ) 2n which was characterized by infrared, 1 H, and 31 P{ 1 H} NMR spectroscopies and elemental analysis. The use of FABMS in this study was undertaken in order to elucidate the chemical options of multiply charged cations in the desorption process from the liquid matrix to the gas phase. The use of additives to the FAB matrix (m-nitrobenzyl alcohol) was demonstrated for the P4 complexes which do not give spectra in this medium due to a high positive net charge. The addition of triflic acid (HOTf or CF 3 SO 3 H) to the FAB matrix/analyte solution was shown to assist in the MS analysis of cationic complexes with up to six charges and a mass range up to m/z 4000. When HOTf is added, bound OTfanions are formed and are attached to the cationic complex, lowering the net charge to +1. The method of using matrix additives as opposed to chemically synthesizing the OTfcompounds is a convenient in situ method which produces species that are capable of being analyzed by FABMS.