Tantalum isocyanide complexes: Tai(CNDipp)6 (dipp is 2,6-diisopropylphenyl) and ionic [ta(CNDipp)7][ta(CNDipp)6], a formal disproportionation product of the 17-electron ta 0 metalloradical ta(CNDipp)6

William W. Brennessel, Alexander Romanenkov, Victor G. Young, John E. Ellis

Research output: Contribution to journalArticle

Abstract

Treatment of tetraethylammonium hexacarbonyltantalate, [Et 4 N][Ta(CO) 6 ], with 1.1 equivalents of molecular iodine (I 2 ) in tetrahydrofuran (THF) at 200 K, followed by the addition of 6.0 equivalents of 2,6-diisopropylphenyl isocyanide (CNDipp) and slow warming to 293 K over a 24 h period gave the tantalum(I) iodide derivative hexakis(2,6-diisopropylphenyl isocyanide-κC)iodidotantalum(I), [TaI(C 13 H 17 N) 6 ] or TaI(CNDipp) 6 , 1. Recrystallization of this substance from pentane provided deep-red nearly black parallelepipeds of the product, which was characterized by single-crystal X-ray diffraction. Addition of 1 in THF at 200 K to a suspension of an excess (5.8 equivalents) of caesium graphite (CsC 8 ), followed by warming, filtration, and solvent removal, afforded a dark-green oily solid of unknown composition, from which several red–brown rhombohedral plates of the ditantalum salt heptakis(2,6-diisopropylphenyl isocyanide-κC)tantalum hexakis(2,6-diisopropylphenyl isocyanide-κC)tantalate, [Ta(C 13 H 17 N) 7 ][Ta(C 13 H 17 N) 6 ] or [Ta(CNDipp) 7 ][Ta(CNDipp) 6 ], 2, were harvested. Salt 2 is a unique substance, as it is the only known example of a salt containing a homoleptic cation, [ML x ] + , and a homoleptic anion, [ML y ] , with the same transition metal and π-acceptor ligand L. In solution, 2 undergoes full comproportionation to afford the recently reported 17-electron paramagnetic zerovalent tantalum complex Ta(CNDipp) 6 , the only known isolable TaL 6 complex of Ta 0 .

Original languageEnglish (US)
Pages (from-to)135-140
Number of pages6
JournalActa Crystallographica Section C: Structural Chemistry
Volume75
DOIs
StatePublished - Jan 1 2019

Keywords

  • 2,6-diisopropylphenyl
  • Crystal structure
  • Homoleptic
  • Isocyanide
  • Low valent
  • Monocapped trigonal prism
  • Seven-coordinate
  • Tantalum

PubMed: MeSH publication types

  • Journal Article

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