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Synthesis and Reactivity of Cationic Bis(N‐Heterocyclic Dicarbene) Ruthenium(II) Complexes
Author(s) -
Tubaro Cristina,
Bertinazzo Davide,
Monticelli Marco,
Saoncella Omar,
Volpe Andrea,
Basato Marino,
Badocco Denis,
Pastore Paolo,
Graiff Claudia,
Venzo Alfonso
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201301583
Subject(s) - chemistry , ruthenium , benzonitrile , carbene , transmetalation , medicinal chemistry , methylene bridge , reactivity (psychology) , isocyanide , ligand (biochemistry) , stereochemistry , cationic polymerization , nucleophile , nitrile , organic chemistry , catalysis , medicine , biochemistry , alternative medicine , receptor , pathology
Four ruthenium(II) N‐heterocyclic dicarbene complexes of general formula [Ru{MeIm(CH 2 ) n ImMe} 2 (RCN) 2 ][PF 6 ] 2 ( 1 : n = 1, R = Me; 2 : n = 1, R = Ph; 3 : n = 2, R = Me; 4 : n = 2, R = Ph; MeIm = 3‐methylimidazol‐2‐yliden‐1‐yl) have been synthesised by transmetalation of the dicarbene ligand from a dicarbene silver complex with [RuCl 2 (COD)] x (COD = 1,5‐cyclooctadiene) or [RuCl 2 ( p ‐cymene)] 2 as ruthenium precursors. The relative position of the coordinated nitrile molecules ( cis or trans ) depends on the group that links the two carbene moieties: the dicarbene with the methylene bridge affords the trans isomer, whereas the cis complex is obtained with the ethylene bridge. The lability of coordinated nitriles towards entering nucleophiles, in particular, cyclohexyl and tert ‐butyl isocyanide, has been carefully checked, and the corresponding substitution complexes [Ru{MeIm(CH 2 ) n ImMe} 2 (RNC) 2 ][PF 6 ] 2 ( 6 : n = 1, R = Cy; 7 : n = 2, R = Cy; 8 : n = 2, R = t Bu) have been synthesised. The trans complexes are more inert than the cis ones, and benzonitrile is a better leaving group than acetonitrile; these characteristics allow a proper tuning of the coordination set and the stereoelectronic properties of these dicarbene ruthenium complexes. The X‐ray crystal structures of 1 and 7 have also been determined.