Studies on α-C3S52- (dmit2-) and its dinuclear Ni(II) complex: Spectroscopic and structural characterization

Jonathan G. Breitzer, Thomas B. Rauchfuss

Research output: Contribution to journalArticlepeer-review

Abstract

The optical properties of the dmit2- ion (dmit2- = 4,5-dimercapto-1,3-dithiol-2-thiolate) have been characterized under a range of conditions. The oxidatively sensitive anion is highly solvatochromic: λ(max) = 504 (H2O), 514 (MeOH), 568 (MeCN), and 632 nm (DMF). With a shift in absorption maximum of 4000 cm-1 (DMF versus H2O), dmit2- is possibly the most solvatochromic species known. The dianion is monoprotonated by NH4+ and binds CS2 to form a thioxanthate (C3S5 · CS22-). 13C NMR measurements of 13C-enriched dmit2- demonstrated that C3S5 · CS22- exchanges with free CS2 via an associative pathway involving binding of a second molecule of CS2. Titration with acid showed that the M2dmit (M = Na, Cs) dissolves to give the dianion in protic solvents, rather than Hdmit-. The conversion of α-C3S52- to its β-isomer ('Steimecke rearrangement') occurs Very slowly with purified Na2dmit, in contrast to the literature method. The salt (NBu4)2[Ni(dmit)2] is also highly solvatochromic but its behavior does not follow any simple pattern. Treatment of (NBu4)2[Ni(dmit)2] with 1/3 equiv. of [Ni(NCMe)6] (BF4)2 gave the dinuclear compound (NBu4)2[Ni2(dmit)3], the first Ni-dmit2- complex with a Ni/dmit2- ratio that is not 1:2. The binuclear salt crystallizes as the CH2Cl2 solvate as dark purple prisms. The planar Ni(dmit)22- is bridged to Ni(dmit) via two sulfur atoms; the anion features a short Ni-Ni distance of 2.71 Å. (C) 2000 Elsevier Science Ltd.

Original languageEnglish (US)
Pages (from-to)1283-1291
Number of pages9
JournalPolyhedron
Volume19
Issue number10
DOIs
StatePublished - May 30 2000

Keywords

  • Acid-base
  • Carbon disulfide
  • Dinuclear complexes
  • Dithiolene
  • Nickel
  • Solvatochromism

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Chemistry

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