Building blocks for conducting polymers or NLO materials are the linear, unsaturated carbon chain bridged manganese complexes 1(n+) (n=0-2). All oxidation states were investigated spectroscopically and by X-ray structure determinations. The analytical data confirm a communication of the electrons over the C(4) chain-a prerequisite for electrical conductivity and NLO properties of oligo- or polymeric materials.

The dinuclear mixed-valent complex [(MeC5H4)(dmpe)MnC(2)Mn(dmpe)(C5H4Me)](+)[(eta2-MeC5H4)3Mn](-)[1](+)[2]- (dmpe=1,2-bis(dimethylphosphanyl)ethane) was prepared by the reaction of [Mn(MeC5H4)2] with dmpe and Me(3)SnC[triple chemical bond]CSnMe3. The reactions of [1](+)[2]- with K[PF6] and Na[BPh4] yielded the corresponding anion metathesis products [(MeC5H4)(dmpe)MnC2Mn(dmpe)(C5H4Me)][PF6] ([1][PF6]) and [(MeC5H4)(dmpe)MnC2Mn(dmpe)(C5H4Me)][BPh4] ([1][BPh4]). These mixed-valent species can be reduced to the neutral form by reaction with Na/Hg. The obtained complex [(MeC5H4)(dmpe)MnC2Mn(dmpe)(C5H4Me)] (1) displays a triplet/singlet spin equilibrium in solution and in the solid state, which was additionally studied by DFT calculations. The diamagnetic dicationic species [(MeC5H4)(dmpe)MnC2Mn(dmpe)(C5H4Me)][PF6]2 ([1][PF6]2) was obtained by oxidizing the mixed-valent complex [1][PF6] with one equivalent of [Fe(C5H5)2][PF6]. Both redox processes are fully reversible. The dinuclear compounds were characterized by NMR, IR, UV-visible, and Raman spectroscopy, cyclic voltammetry, and magnetic susceptibility measurements. X-ray diffraction studies were performed on [1][2], [1][PF6], [1][BPh4], and [1][PF6]2.

No abstract

The mononuclear vinylidene complexes of the type Mn(C5H4R‘)(R‘ ‘2PCH2CH2PR‘ ‘2)(CC(R1)(SnMe3)) were obtained by the reaction of Mn(C5H4R‘)(η6-cycloheptatriene) (R‘ = H, 1a; CH3, 1b) with 1 equiv of R1−C⋮C−SnMe3 (R1 = SnMe3, C6H5, C4H3S, C6H4CH3) and R‘ ‘2PCH2CH2PR‘ ‘2 (R‘ ‘ = CH3 (dmpe), C2H5 (depe)) in toluene at 50 °C for 3 h. The reactions of these tin-substituted complexes with 1 equiv of 1.0 M TBAF yielded the corresponding parent vinylidene species Mn(C5H4R‘)(R‘ ‘2PCH2CH2PR‘ ‘2)(CC(R1)(H)). Treatment of some of these vinylidene species with 1 equiv of [Cp2Fe][PF6] led to the oxidative coupling product [(C5H4R‘)(R‘ ‘2PCH2CH2PR‘ ‘2)Mn⋮C−CHR1−CHR1−C⋮Mn(R‘ ‘2PCH2CH2PR‘ ‘2)(C5H4R‘)][PF6]2 (R‘ = CH3, R‘ ‘ = CH3, R1 = H; R‘ = CH3, R‘ ‘ = CH3, R1 = C6H5; R‘ = CH3, R‘ ‘ = CH3, R1 = C4H3S; R‘ = H, R‘ ‘ = C2H5, R1 = H; R‘ = H, R‘ ‘ = C2H5, R1 = C6H5; R‘ = H, R‘ ‘ = C2H5, R1 = C4H3S). In some cases these products of oxidative coupling, [(C5H4R‘)(R‘ ‘2PCH2CH2PR‘ ‘2)Mn⋮C−CHR1−CHR1−C⋮Mn(R‘ ‘2PCH2CH2PR‘ ‘2)(C5H4R‘)][PF6]2, were accompanied by formation of dinuclear complexes of the type [(C5H4R‘)(R‘ ‘2PCH2CH2PR‘ ‘2)Mn⋮C−CR1CR1−C⋮Mn(R‘ ‘2PCH2CH2PR‘ ‘2)(C5H4R‘)][PF6]2 and of the cationic carbyne complexes [(C5H4R‘)(R‘ ‘2PCH2CH2PR‘ ‘2)Mn⋮C−CH2R1][PF6] obtained by proton transfer. Reduction of these dinuclear complexes with Cp2*Co yielded back the corresponding mononuclear precursor complexes involving a reductive decoupling process. Both the reductive coupling and the oxidative coupling are fully reversible, which is supported by DFT calculations. The mononuclear and the dinuclear compounds were characterized by NMR, IR, and cyclic voltammetric studies. X-ray diffraction studies have been performed on complexes 3a, 11, 13a, 15a, and 22b.

No abstract

No abstract

Bausteine für leitfähige Polymere oder NLO‐Materialien sind die durch lineare, ungesättigte Kohlenstoffketten verbrückten Mangankomplexe 1n+ (n=0–2). Alle Oxidationstufen wurden spektroskopisch und strukturanalytisch untersucht. Die analytischen Daten belegen eine Kommunikation der Elektronen über die C4‐Kette hinweg – eine Voraussetzung für elektrische Leitfähigkeit und NLO‐Eigenschaften oligo‐ oder polymerer Materialien.

The syntheses and X‐ray crystal structures of [([18]crown‐6)2Cs]+[Cp3Mn]− (1), [([18]crown‐6)2Cs]+[Cp′3Mn]− (2), [CsCp′] (3), [(CsCp′)2([18]crown‐6)] (4), and Cs[MnCp3] (5), and the synthesis of Cs[MnCp′3] (6) are reported (Cp′=C5H4Me). The anions [Cp3Mn]− (1−) and [Cp′3Mn]− (2−) are characterized by η2 coordination of all three Cp or Cp′ rings. Measurements of the magnetic susceptibilities χM resulted in values of μeff=6.20μB (300 K), μeff=6.33μB (301 K), and μeff=5.83 μB (300 K) for 1, 2, and 5, respectively, which are indicative of high‐spin d5‐Mn2+ centers. Density functional calculations illustrate that the coordination mode of 1− is characteristic for its sextet electronic ground state. Compound 3 forms infinite chains of cesocene‐type sandwiches in the solid state, which are broken up into small subunits by the addition of crown ether to form 4. Compound 5 is a rare example of a (10,3)‐a racemic interpenetrating network that crystallizes in the orthorhombic space group Pbca.