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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
Author(s) -
Brennessel William W.,
Romanenkov Alexander,
Young Victor G.,
Ellis John E.
Publication year - 2019
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229619000834
Subject(s) - isocyanide , homoleptic , chemistry , medicinal chemistry , tantalum , iodide , tetrahydrofuran , tetrafluoroborate , inorganic chemistry , solvent , organic chemistry , ionic liquid , metal , catalysis
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‐κ C )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‐κ C )tantalum hexakis(2,6‐diisopropylphenyl isocyanide‐κ C )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 Ta L 6 complex of Ta 0 .