Facile Access to Redox‐Active C₂‐Bridged Complexes with Half‐Sandwich Manganese End Groups

Abstract

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.

Electronic Properties of Poly‐Yne Carbon Chains and Derivatives with Transition Metal End‐Groups

“…Clearly, the magnetic coupling between the redox centers is controlled by the torsion angle between the terminal spin carriers, which allows the inversion of the BS state over the triplet ground state. It has to be mentioned that such a behavior has also been theoretically observed for the related complex [{Mn(dHpe)(MeC 5 H 4 )} 2 (µ‐C≡C) 2 ] …”

Syntheses, structures and redox properties of {Os(PPh3)2Cp}2{μ-(CC)x} (x=2, 3, 4): Comparisons with the Ru analogues

“…Many studies have been carried out with complexes containing chains of carbon atoms, C 2x , linking metal centres such as Mn(dppe)Cp 0 (Cp 0 = Cp, Cp Me ) [10], Re(NO)(PPh 3 )Cp* [11], Fe(dppe)Cp* [12], Ru(PP)Cp 0 [(PP)Cp 0 = (PPh 3 ) 2 Cp, (dppe)Cp*] [13], Os(dppe)Cp* [14], Ru 2 (LL) 4 [15,16], and Pt(Ar)(PAr 0 3 ) 2 (Ar = tol, C 6 F 5 , Ar 0 = tol) [17]. Recent reviews of this chemistry are available [18][19][20][21].…”

A Fully Charge‐Delocalized Two‐Dimensional Porphyrin System with Two Different Class III States

“…Firstly,t he aromaticity of the porphyrin ring is significantly deteriorated as indicated by the prominentu pfield shifto ft he b-proton signal (d = 6.15 ppm) by 2.08 ppm (Figures 2a and 9a). Secondly, the cumulenic structure is evident for the Ru=C=C=C meso moieties from the 13 CNMR spectrum (at 126 MHz) of [1 2 + ](BArF) 2 observed in CD 2 Cl 2 at room temperature. 13 CNMR signal for the Ru-CCa toms in [1 2 + ](BArF) 2 appearing at d = 221 ppm as at riplets ignal (J(C,P) = 20.7 Hz), which is typical for an allenylidene metal skeleton (Figure9c).…”

“…Herein, we disclose the synthesis of a porphyrin–nickel complex bearing four redox‐active Cp*(dppe)Ru‐C≡C pendants 1 (Figure b, Cp*=η 5 ‐C 5 Me 5 , dppe=1,2‐bis(diphenylphosphino)ethane) and its conversion to mono‐ and dicationic species with the different oxidation states, in both of which the positive charges are fully delocalized over the 2D systems. Although MV systems of 1D dinuclear species containing (η 5 ‐C 5 R 5 )L n M‐C≡C‐ fragments (M=Fe, Ru, Re, or Mn, L n =monophosphine, diphosphane, and nitrosyl) have been studied extensively by Lapinte and Halet, Bruce and Low, Gladysz et al., Berke et al . and others, there are few reports on 2D systems with multiple redox centers ,.…”

“…[9] Herein, we disclose the synthesis of ap orphyrin-nickel complex bearing four redox-active Cp*(dppe)Ru-CCp endants 1 (Figure 1b,C p* = h 5 -C 5 Me 5 ,d ppe = 1,2-bis(diphenylphosphino)ethane) and its conversion to mono-and dicationic species with the different oxidations tates, in both of which the positive chargesa re fully delocalizedo ver the 2D systems. Al-thoughM Vs ystemso f1 Dd inuclears pecies containing (h 5 -C 5 R 5 )L n M-CCfragments (M = Fe, Ru,R e, or Mn, L n = monophosphine, diphosphane, and nitrosyl)h ave been studied extensively by Lapinte and Halet, [10] Bruce and Low, [11] Gladysz et al, [12] Berke et al [13] and others, [14] there are few reports on 2D systemsw ith multiple redox centers. [7b,c, 14a, 15] To the best of our knowledge, only one example of a2 Dc lass III system was reported, where it constitutes as quare-shaped MV system,b ut except electrochemical property,t he detail electronic structure of it has not been investigated.…”