Acetylenes Rearranging on Ruthenium-Porphyrinogen and Leading to Vinylidene and Carbene Functionalities

Abstract

Through a proton‐transfer reaction a porphyrinogen assists the transformation of terminal acetylenes into Ru–vinylidenes, which are the entry point to a variety of Ru–carbenes and Ru–cumulenes. The scheme (in which the porphyrinogen is stylized) shows the reversible interconversion of an acetylide into a divinylidene unit.

31P NMR Chemical Shift Tensors: Windows into Ruthenium Phosphinidene Complex Electronic Structures

“…First investigated by Floriani et al in 2001, 14,15 the ruthenium(II) platform [1] 2− has been reported to support a variety of ruthenium−main group multiple bonds. 14−16 Our studies began by interrogating the reaction between Na 2 (DME) 6 [1] and t BuPA by NMR spectroscopy in tetrahydrofuran (THF)-d 8 .…”

“…Our recent work on phosphinidene transfer from dibenzo-7-phosphanorbornadiene RP A compounds ( A = C 14 H 10 or anthracene) has positioned us well to explore [RP] unit delivery to a metal center. We now report facile phosphinidene transfer from a series of RP A compounds to the ruthenium­(II) calix[4]­pyrrole (“porphyrinogen”) complex Na 2 (DME) 6 [ 1 ] (Figure , DME = 1,2-dimethoxyethane). , The electronic structure of the resulting RuP bond is strongly influenced by the substituent, an effect that we have characterized through 31 P MAS SSNMR spectroscopy. The chemical shift tensor is shown to be a direct experimental handle on the σ RuP /π RuP * energy gap and its orientation on the nature of the phosphorus–substituent σ PR bond.…”

“…First investigated by Floriani et al in 2001, , the ruthenium­(II) platform [ 1 ] 2– has been reported to support a variety of ruthenium–main group multiple bonds. − Our studies began by interrogating the reaction between Na 2 (DME) 6 [ 1 ] and t BuP A by NMR spectroscopy in tetrahydrofuran (THF)- d 8 . Although originally reported to have a 1 H NMR spectrum consistent with [ 1 ] 2– being a closed-shell complex, we have found THF- d 8 solutions of Na 2 (DME) 6 [ 1 ] to exhibit a single paramagnetically shifted resonance at 1 H δ −28.3 (s, 8H) ppm, indicating that [ 1 ] 2– is likely of intermediate spin S = 1, as is typical for square-planar d 6 ruthenium­(II) complexes. − Monitoring the reaction between Na 2 (DME) 6 [ 1 ] and t BuP A over 24 h showed gradual loss of the 1 H δ –28.3 ppm resonance and growth of a new resonance in the 31 P­{ 1 H} NMR spectrum at δ 1047 ppm, characteristic of a bent phosphinidene .…”

The impact of alkali and alkaline earth metals on green ammonia synthesis

“…AM in homogeneous nitrogen reduction and ammonia synthesis (A) Catalytic reduction of N 2 in the presence of [(TPB)Fe(N 2 )][Na(12-crown-4) 2 ] using excess KC 8 and HBAr F 4 $2Et 2 O in diethyl ether (Et 2 O) at -78 C. Adapted with permission from Peters et al48 Copyright 2013 Springer Nature. (B) The N-N distances of selected TM-N 2 complexes with end-on or side-on interactions to AM cations, and several N 2 -derived multinuclear TM-N complexes with nitride-AM cation interactions 44,45,13,[49][50][51][52][53][54][55][56][57][58][59][60][61][62][63]. Noted that the N-N bond in multinuclear TM-N complexes is dissociated.…”

Open-shell organometallics: reactivity at the ligand

“…This reaction was shown to be reversible, and the bis-vinylidene complex can be reduced back to the respective acetylide complex with sodium naphthalenide. 57 Similar reactivity has been observed for the iron complex [Fe(Cp*)(dppe)-(CRCH)], yielding the bis-vinylidene complex {[Fe(Cp*)(dppe)] 2 (m 2 -CCHCHC)} 2þ upon one-electron oxidation. 58 with Cu þ .…”