Lewis Acid Chemistry of a Cationic [CCH] Subunit in a Bisdisphenoidal Eight-Atom Tetrairon–Tetracarbon Cluster

Abstract

Reaction of [(η 5 -C 5 H 4 Me) 4 Fe 4 (HCCH)-(HCCBr)](PF 6 ) ([2](PF 6 )) with AgPF 6 in acetonitrile gave [(η 5 -C 5 H 4 Me) 4 Fe 4 (HCCH)(HCCNCMe)](PF 6 ) 2 ([3]-(PF 6 ) 2 ). The X-ray diffraction study revealed that the cationic [CCH] subunit is stabilized through coordination of the acetonitrile molecule to the cationic carbon atom. As a synthon for a donor-free [(η 5 -C 5 H 4 Me) 4 Fe 4 (HCCH)(HCC)] 2+ , [(η 5 -C 5 H 4 Me) 4 Fe 4 (HCCH)(HCCL)](PF 6 ) 2 ([6](PF 6 ) 2 , L = pyrazine) was synthesized by the reaction of [2](PF 6 ) with AgPF 6 in the presence of pyrazine. Treatment of [6](PF 6 ) 2 with tertiary amines in acetonitrile led to deprotonation of acetonitrile to form [(η 5 -C 5 H 4 Me) 4 Fe 4 (HCCH)-(HCCCH 2 CN)](PF 6 ) ([11](PF 6 )). Treatment of [6](PF 6 ) 2 with maleimide in the presence of tertiary amine in acetonitrile allowed the functionalization of the coordinated acetonitrile through the nucleophilic attack of maleimide at the nitrile carbon atom.

Activation of Isocyanides and Hydrosilanes by a Cationic [CCH] Subunit in a Tetrairon–Tetracarbon Cluster

“…[(η 5 -C 5 H 4 Me) 4 Fe 4 -(HCCH)(HCC-NC 4 H 4 N)](PF 6 ) 2 (1) was prepared according to a literature method. 7 NMR spectra were recorded on a JEOL JNM-ECA500. Chemical shifts are reported in ¤, referenced to 1 H (of residual protons) and 13 C signals of deuterated solvents as internal standards.…”

“…5 Coordination with a transition metal through π-back donation of the metal dπ electrons is an efficient method for stabilizing the electron-deficient species. 6 The Lewis acid chemistry of an ethynyl cation bridged over a butterfly-type tetrairon core has been investigated recently by us, 7 generation of which has been postulated in heterogeneous catalytic reactions (FT process). 2 (1).…”

Crystal structure oftert-butyl-N-phenylcarbonitrilium tetrachloridoaluminate

“…A search in the Cambridge Structural Database (Version 5.35, last update May 2014; Groom & Allen, 2014) showed five structures of nitrilium salts (Gjøystdal & Rømming, 1977;MacLaughlin et al, 1983;Casey et al, 1988;Bykhovskaya et al, 1993, Okazaki et al, 2013, and two structures of nitrilium ylides (Janulis et al, 1984;Doherty et al, 1999)). The title compound is very closely related to N-(2,6-dimethylphenyl)acetonitrilium tetrafluoridoborate (Gjøystdal & Rømming, 1977), which has an N C bond length of 1.131 Å , and (Nphenyl)(tert-butyl)carbonitrilium trifluoromethanesulfonate [van Dijk et al, 2014; N C bond length of 1.125 (3) Å ], both of which feature similar bond lengths and angles for the nitrilium group.…”

C(sp3)–N(sp) Bond Cleavage of Isocyanides at a Cationic [CCH] Subunit in a Bisdisphenoidal Eight-atom Tetrairon–Tetracarbon Cluster

“…5 We have reported the Lewis acid chemistry of the cationic [CCH] subunit in a bisdisphenoidal eight-atom tetrairontetracarbon cluster. 6 4 Fe 4 (HCCH)(HCCCN)](PF 6 ) (2). The tert-butyl cation was trapped as the adduct with pyrazine.…”