Stable paramagnetic bis(alkynyl) manganese complexes

Krivykh, V. V.; Еременко, И. Л.; Veghini, Dario; Petrunenko, I. A.; Pountney, Dean L.; Unseld, Dieter; Berke, Heinz

doi:10.1016/0022-328x(95)05926-g

Cited by 29 publications

(51 citation statements)

References 32 publications

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“…The Mn±C 1 and Mn±C 3 bond lengths are similar (around 1.96 ä), and are in the same range as those found for symmetric transbis-alkynyl complexes. [51,53] The CC bond length in the tri- Synthesis of trans-iodo-alkynyl manganese species: Thus far, we have described the synthesis of asymmetrically substituted trans-bis-alkynyl manganese complexes using manganese vinylidene complexes as starting materials. Another seemingly convenient route for obtaining the required asymmetric Mn II trans-bis-alkynyl manganese complexes might be [47] As an alternative, conversion of the complex [Mn(MeC 5 H 4 )(dmpe)I] [60] with [Me 3 SnCCSiMe 3 ] and dmpe was considered, which indeed yielded the expected d 5 paramagnetic trans-iodo-alkynyl compound [Mn(dmpe) 2 (C CSiMe 3 )I] (9) (Scheme 3).…”

Section: (Cch)} 2 (M-c 4 )] [Pf 6 ] (11) By C±c Coupling Of [Mn(dmpe)mentioning

confidence: 99%

Generation and Coupling of [Mn(dmpe)₂(CCR)(CC)]^. Radicals Producing Redox‐Active C₄‐Bridged Rigid‐Rod Complexes

Fernández

Venkatesan

Blacque

et al. 2003

Chemistry A European J

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The symmetric d(5) trans-bis-alkynyl complexes [Mn(dmpe)(2)(C triple bond CSiR(3))(2)] (R = Me, 1 a; Et, 1 b; Ph, 1 c) (dmpe = 1,2-bis(dimethylphosphino)ethane) have been prepared by the reaction of [Mn(dmpe)(2)Br(2)] with two equivalents of the corresponding acetylide LiC triple bond CSiR(3). The reactions of species 1 with [Cp(2)Fe][PF(6)] yield the corresponding d(4) complexes [Mn(dmpe)(2)(C triple bond CSiR(3))(2)][PF(6)] (R = Me, 2 a; Et, 2 b; Ph, 2 c). These complexes react with NBu(4)F (TBAF) at -10 degrees C to give the desilylated parent acetylide compound [Mn(dmpe)(2)(C triple bond CH)(2)][PF(6)] (6), which is stable only in solution at below 0 degrees C. The asymmetrically substituted trans-bis-alkynyl complexes [Mn(dmpe)(2)(C triple bond CSiR(3))(C triple bond CH)][PF(6)] (R = Me, 7 a; Et, 7 b) related to 6 have been prepared by the reaction of the vinylidene compounds [Mn(dmpe)(2)(C triple bond CSiR(3))(C=CH(2))] (R = Me, 5 a; Et, 5 b) with two equivalents of [Cp(2)Fe][PF(6)] and one equivalent of quinuclidine. The conversion of [Mn(C(5)H(4)Me)(dmpe)I] with Me(3)SiC triple bond CSnMe(3) and dmpe afforded the trans-iodide-alkynyl d(5) complex [Mn(dmpe)(2)(C triple bond CSiMe(3))I] (9). Complex 9 proved to be unstable with regard to ligand disproportionation reactions and could therefore not be oxidized to a unique Mn(III) product, which prevented its further use in acetylide coupling reactions. Compounds 2 react at room temperature with one equivalent of TBAF to form the mixed-valent species [[Mn(dmpe)(2)(C triple bond CH)](2)(micro-C(4))][PF(6)] (11) by C-C coupling of [Mn(dmpe)(2)(C triple bond CH)(C triple bond C*)] radicals generated by deprotonation of 6. In a similar way, the mixed-valent complex [[Mn(dmpe)(2)(C triple bond CSiMe(3))](2)(micro-C(4))][PF(6)] [12](+) is obtained by the reaction of 7 a with one equivalent of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). The relatively long-lived radical intermediate [Mn(dmpe)(2)(C triple bond CH)(C triple bond C*)] could be trapped as the Mn(I) complex [Mn(dmpe)(2)(C triple bond CH)(triple bond C-CO(2))] (14) by addition of an excess of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) to the reaction mixtures of species 2 and TBAF. The neutral dinuclear Mn(II)/Mn(II) compounds [[Mn(dmpe)(2)(C triple bond CR(3))](2)(micro-C(4))] (R = H, 11; R = SiMe(3), 12) are produced by the reduction of [11](+) and [12](+), respectively, with [FeCp(C(6)Me(6))]. [11](+) and [12](+) can also be oxidized with [Cp(2)Fe][PF(6)] to produce the dicationic Mn(III)/Mn(III) species [[Mn(dmpe)(2)(C triple bond CR(3))](2)(micro-C(4))][PF(6)](2) (R = H, [11](2+); R = SiMe(3), [12](2+)). Both redox processes are fully reversible. The dinuclear compounds have been characterized by NMR, IR, UV/Vis, and Raman spectroscopies, CV, and magnetic susceptibilities, as well as elemental analyses. X-ray diffraction studies have been performed on complexes 4 b, 7 b, 9, [12](+), [12](2+), and 14.

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Section: (Cch)} 2 (M-c 4 )] [Pf 6 ] (11) By C±c Coupling Of [Mn(dmpe)mentioning

confidence: 99%

Generation and Coupling of [Mn(dmpe)₂(CCR)(CC)]^. Radicals Producing Redox‐Active C₄‐Bridged Rigid‐Rod Complexes

Fernández

Venkatesan

Blacque

et al. 2003

Chemistry A European J

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“…These possibilities have been corroborated by recent studies in our group. [36,46,57,74,75,101] For instance, we have published the synthesis of redox-active dinuclear complexes of the type [{Mn(dmpe) 2 (X)} 2 (µ-C 4 …”

Section: Introductionmentioning

confidence: 99%

“…We have already reported some of the results involving manganese centers with strong-field ligands such as phosphanes. [36,46,57,63,74,75] We subsequently decided to synthesize and study the properties of molecules with weakfield ligands, such as tmeda, expecting high-spin configurations of the metal centers.…”

Section: Introductionmentioning

confidence: 99%

“…Specifically, they should consist of an all-carbon chain capped by two redox-active metal termini. [36,46,57,63,74,75] We have sought to explore reactions to prepare mono-and dinuclear precursors containing polyyne ligands. We have already reported some of the results involving manganese centers with strong-field ligands such as phosphanes.…”

Section: Introductionmentioning

confidence: 99%

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Mono‐ and Dinuclear High‐Spin Half‐Sandwich Manganese(II) Complexes Containing Acetylide and TMEDA Ligands

et al. 2004

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“…[28][29][30][31][32][33][34][35][36] Such principal possibilities have been corroborated by recent studies by our group. [18][19][20][21][22][23] For such a process to be initiated in half-sandwich Mn I chemistry, we believed the complex [Mn(C 5 H 4 Me)(η 6 -cycloheptatriene)] (1) [37] would be an excellent starting material, since facile cycloheptatriene exchange could be expected to occur with electron donating ligands such as phosphanes or acetylenes. [38,39] Further reactivity with disubstituted tin acetylides was anticipated, thus leading to the desired dinuclear vinylidene species.…”

Section: Resultsmentioning

confidence: 99%

New Access to Homodinuclear Half‐Sandwich Vinylidenemanganese Complexes

et al. 2005

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The d 6 low-spin Mn I half-sandwich dinuclear complexes of the type [{Mn(MeC 5 H 4 )(R 2 PCH 2 CH 2 PR 2 )=C=C(SnMe 3 )} 2 {X}] (X = {µ-1,4-C 6 H 4 }, R = Me, 2a; X = {µ-1,4-C 6 H 4 }, R = Et, 2b; X = {µ-1,3-C 6 H 4 }, R = Me, 3a; X = {µ-1,3-C 6 H 4 }, R = Et, 3b; X = {µ-4,4-C 6 H 4 -C 6 H 4 }, R = Me, 4a; X = {µ-4,4-C 6 H 4 -C 6 H 4 }, R = Et, 4b; X = {µ-1,4-C 4 H 2 S}, R = Me, 5a; X = {µ-1,4-C 4 H 2 S}, R = Et, 5b) were obtained by the treatment of [Mn(C 5 H 4 Me) (η 6 -cycloheptatriene)] with 0.5 equiv.

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Stable paramagnetic bis(alkynyl) manganese complexes

Cited by 29 publications

References 32 publications

Generation and Coupling of [Mn(dmpe)₂(CCR)(CC)]^. Radicals Producing Redox‐Active C₄‐Bridged Rigid‐Rod Complexes

Generation and Coupling of [Mn(dmpe)₂(CCR)(CC)]^. Radicals Producing Redox‐Active C₄‐Bridged Rigid‐Rod Complexes

Mono‐ and Dinuclear High‐Spin Half‐Sandwich Manganese(II) Complexes Containing Acetylide and TMEDA Ligands

New Access to Homodinuclear Half‐Sandwich Vinylidenemanganese Complexes

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Stable paramagnetic bis(alkynyl) manganese complexes

Cited by 29 publications

References 32 publications

Generation and Coupling of [Mn(dmpe)2(CCR)(CC)]. Radicals Producing Redox‐Active C4‐Bridged Rigid‐Rod Complexes

Generation and Coupling of [Mn(dmpe)2(CCR)(CC)]. Radicals Producing Redox‐Active C4‐Bridged Rigid‐Rod Complexes

Mono‐ and Dinuclear High‐Spin Half‐Sandwich Manganese(II) Complexes Containing Acetylide and TMEDA Ligands

New Access to Homodinuclear Half‐Sandwich Vinylidenemanganese Complexes

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Generation and Coupling of [Mn(dmpe)₂(CCR)(CC)]^. Radicals Producing Redox‐Active C₄‐Bridged Rigid‐Rod Complexes

Generation and Coupling of [Mn(dmpe)₂(CCR)(CC)]^. Radicals Producing Redox‐Active C₄‐Bridged Rigid‐Rod Complexes