The straightforward synthesis of a new unsymmetrical hydroxy-tethered N-heterocyclic carbene (NHC) ligand, HL, is presented. The free ligand exhibits an unusual OH-carbene hydrogen-bonding interaction. This OH-carbene motif was used to yield 1) the first tantalum complex displaying both a Fischer- and Schrock-type carbene ligand and 2) a unique NHC-based early/late heterobimetallic complex. More specifically, the protonolysis chemistry between the ligand's hydroxy group and imido-alkyl or alkylidene-alkyl tantalum precursor complexes yielded the rare monometallic tantalum-NHC complexes [Ta(XtBu)(L)(CH tBu) ] (X=N, CH), in which the alkoxy-carbene ligand acts as a chelate. In contrast, HL only binds to rhodium through the NHC unit in [Rh(HL)(cod)Cl] (cod=cycloocta-1,5-diene), the hydroxy pendant arm remaining unbound. This bifunctional ligand scaffold successfully promoted the assembly of rhodium/tantalum heterobimetallic complexes upon either 1) the insertion of [Rh(cod)Cl] into the Ta-NHC bond in [Ta(NtBu)(L)(CH tBu) ] or 2) protonolysis between the free hydroxy group in [Rh(HL)(cod)Cl] and one alkyl group in [Ta(NtBu)(CH tBu) ].

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Table of contents 1. Experimental procedures and NMRs 2. X-ray diffraction data 3. UV-vis analyses 4. Catalytic tests 5. C 2 H 4 /C 2 D 4 experiments 6. References S3 Experimental procedures and NMRs Reagents and solventsAll the reactions were carried out in the glove box or using standard schlenck techniques under N 2 . The commercial compounds stored under N 2 or Ar were used directly without any further purification, while the non-stored under inert atmosphere, they were degassed before use. All solvents, except o-DFB, were taken from MBSPS-800 solvent purification system, then they were degassed and dried using molecular sieves. o-DFB was pre-dried over CaH 2 and then filtered and stored on molecular sieve. NMR1 H, 13 C, 19 F and 31 P NMR spectra were recorded on Bruker Avance 300 and 400 MHz spectrometers. 1 H and 13 C chemical shifts reported are referenced internally to used solvent while 19 F and 31 P chemical shifts are referenced to an external standard of trichlorofluoromethane and phosphoric acid respectively.

Cp*IrH 4 reacts with Hf(Np) 4 (Np = CH 2 C(CH 3 ) 3 ) to yield the heterobimetallic complex [Hf(Np) 3 (μ-H) 3 IrCp*], 2. Treatment of 2 with neopentyl lithium (NpLi) results in the nucleophilic addition of a neopentyl moiety onto the Hf center, restoring Hf(Np) 4 and displacing the Cp*IrH 3 iridate fragment. By contrast, treatment of the tantalum/iridium analogue, [Ta(Np) 3 IrH 2 (Cp*)], 1, with NpLi triggers the α-hydrogen abstraction at a Ta-neopentyl moiety and leads to the formation of the alkylidene -ate complex [Li][{Ta(CH t Bu)(Np) 2 }{IrH 2 Cp*}], 4. The benzylidene analogue, [K][{Ta(CHPh)(Np) 2 }{IrH 2 Cp*}], 5, is obtained upon reacting 1 with benzyl potassium. An unusual vinyl oxo species, [{Li(THF) 3 }Ta(O)(Np) 2 {μ-C 2 H 3 }IrH(Cp*)], 6, is formed when the reaction of 1 with NpLi is carried out in THF, due to THF fragmentation.

The facile synthesis of a new 3-hydroxyadamantylfunctionalized N-heterocyclic carbene (NHC) ligand, 2, and its corresponding rhodium complex [Rh(NHC)(COD)Cl], 3, is described. This complex features an unusually large yaw distortion angle (θ = 6.8°) for a monodentate NHC species, which is attributed to its unsymmetrical nature and the steric imbalance between its two wingtips. The comprehensive analysis of the yaw distortion angles in 85 related Rh species featuring various N-substituents is reported to support this hypothesis.

Reduction of high spin paramagnetic complex [(κ2-P, P’-PCH2PCy)FeCl2] 2 by two electrons under N2 resulted in the formation of two isomeric low spin diamagnetic complexes 3trans and 3cis [Fe(κ3-P,C,P’-PCPCy)(H)2(N2)]. Cristallization...

A DFT study of several L→Al(ORF)3 (L=Lewis bases) adducts allowed the identification of (iPr2S)→Al(ORF)3 1‐SiPr2 as a “stable yet reactive” adduct. 1‐SiPr2 was shown to act as a masked Lewis superacid able to release Al(ORF)3 under mild conditions. It could be used to abstract a ORF− ligand from (bipyMe2)Ni(ORF)2 (bipyMe2 : 6,6’‐dimethyl‐2,2’‐dipyridyl) and generate the nickel alkoxide complex [(bipyMe2)Ni(ORF)(iPr2S)]+[(RFO)3Al−F−Al(ORF)3]− 5. Ligand exchange of iPr2S by Ph3P yielded [(bipyMe2)Ni(ORF)(PPh3)]+[(RFO)3Al−F−Al(ORF)3]− 6.