Dinuclear and mononuclear chromium acetylide complexes

Carolina Egler-Lucas*, Olivier Blacque, Koushik Venkatesan, Alberto Lõpez-Hernández, Heinz Berke

*Corresponding author for this work

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Reaction of trans-Cl 2Cr(dmpe) 2 (1) [dmpe = 1,2-bis(dimethylphosphanyl)ethane] with 0.5 equiv. of Me 3Sn-C=C-C=C- SnMe 3 or Me 3Sn-C=C-C 6H 4-C=C- SnMe 3 afforded the dinuclear complexes trans-[Cl(dmpe) 2Cr=C-C=C-C=Cr(dmpe) 2Cl] (2), trans-[Cl(dmpe) 2Cr-C=C-C=C-Cr(dmpe) 2Cl][SnMe 3Cl 2] 2 (2[SnMe 3Cl 2] 2), and trans-[Cl(dmpe) 2Cr-C=C-C 6H 4-C=C-Cr(dmpe) 2Cl][SnMe 3Cl 2] 2 (3[SnMe 3Cl 2] 2), which could be transformed to the 2[PF 6] 2 and 3[BPh 4] 2 salts. Substitutions of the chloride groups in 2 were carried out to achieve the corresponding iodo (4) and (trimethylsilyl)alkynyl (5) complexes. Utilizing similar reactions and treatment with only 1 equiv. of the corresponding alkynyl ligand [Me 3Sn-C=C-R (R = -SnMe 3, -C 6H 5), Me 3Sn-C=C-C=C-R (R = -SiMe 3, -SnMe 3), and Me 3Sn-C=C-C 6H 4-C=C-SnMe 3] allowed us to prepare a series of mononuclear monoacetylide complexes: trans-[Cl(dmpe) 2Cr-C=C-R] [R = -SnMe 3(6),- C 6H 5(7)], trans-[Cl(dmpe) 2Cr-C=C-C=C-R] [R = -SiMe 3(8),-SnMe 3(9)], and trans-[Cl(dmpe) 2Cr-C=C-C 6H 4-C=C-SnMe 3] (10), respectively. The complexes 2, 2[SnMe 3Cl 2] 2, 2[PF 6] 2, 3[SnMe 3Cl 2] 2, 3[BPh 4] 2, and 6-10 displayed paramagnetic behavior. Electrochemical studies performed on the dinuclear complexes (2), (2[SnMe 3Cl 2] 2), (3[SnMe 3Cl 2] 2), and (5) showed one two-electron redox wave revealing a class-I type behavior based on the Robin-Day classification, which is untypical for dinuclear complexes bridged by a butadiyne ligand. The complexes were characterized by NMR, ESI-MS, cyclic voltammetry, EPR spectroscopy, magnetic measurements, and exemplary single-crystal X-ray diffraction studies for 2, 2[SnMe 3Cl 2] 2, 8, 9, and 10. Chromium dinuclear complexes bridged by C 4 units were obtained in good yields. Physical studies done on the dinuclear complexes revealed a class-I behavior(Robin-Day classification). Related mononuclear chromium monoacetylide complexes were also accessible.

Original languageEnglish
Pages (from-to)1536-1545
Number of pages10
JournalEuropean Journal of Inorganic Chemistry
Issue number9
DOIs
Publication statusPublished - Mar 2012
Externally publishedYes

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Keywords

  • Alkynes
  • Chromium
  • Cyclic voltammetry
  • Molecular electronics

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