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Treatment of trans-[Ir(H)(N)2(iPr)4(POCOP)(DMAP)][BAr4f] (2) with H2 (1 bar) under ambient conditions (298 K) results in the formation of a trans-[Ir(H)(η2-H2)(iPr)4(POCOP)(DMAP)][BAr4f] (3) complex. Complex 3 exhibits H-atom site exchange between the bound H2 and the hydride ligands which are mutually trans to one another. A plausible mechanism of this exchange involves metal–ligand cooperativity as studied by computations. [ABSTRACT FROM AUTHOR]

The combination of 6-SIDipp·AlH3 (1) and 5-IDipp resulted in the ring expansion of 6-NHC, while the five-membered NHC remained unchanged, which was subsequently explained by DFT studies. Besides, the substitution chemistry of 1 was also studied with TMSOTf and I2, which gave rise to the substitution of a hydride by triflate or iodide ligands. [ABSTRACT FROM AUTHOR]

Herein, we report two 2,2′-pyridylpyrrolide (PyPyrH) ligand supported magnesium complexes (1 and 2), which demonstrate bright luminescence with a quantum yield of 22% and 14% in the solid state, respectively. Theoretical calculations reveal that their emissive properties originate from the intra- and inter-ligand charge transfer. [ABSTRACT FROM AUTHOR]

There has been considerable interest in recent times to develop transition metal complex systems that can demonstrate metal–ligand cooperativity. It has recently been shown (Wass et al., J. Am. Chem. Soc., 2011, 133, 18463) that early transition metals can cooperate with ligands carrying phosphines as pendant groups, working as metal analogues to frustrated Lewis pairs (FLPs) to mediate in a variety of important reactions. What the current work attempts to do is to show how this concept of metal containing FLPs can be expanded to include late transition metal complexes as well: complexes that have been modified from existing systems that serve as efficient catalysts for homogeneous polymerization. A modified palladium complex has been considered in this regard as an example of a potential late transition metal FLP and studied with full quantum mechanical calculations. The calculations indicate that this complex would be effective at catalyzing ammonia borane dehydrogenation. The possibility of competing side reactions such as reductive elimination have also been considered, and it has been found that such processes would also yield stable products which could act as an FLP in catalyzing reactions such as the dehydrogenation of ammonia borane. The current work therefore expands the scope of metal containing FLPs to include late transition metals and demonstrates computationally the potential of such complexes for exhibiting metal–ligand cooperativity. [ABSTRACT FROM AUTHOR]

Herein, we introduce isocyanide as a ligand in main group chemistry and describe the facile isolation of a Ge(ii) dication. The reaction of 2,6-dimethylphenylisocyanide with GeCl2 leads to the formation of a Ge(ii) dication with two [GeCl3]− molecules as counter anions. The dicationic Ge(ii) center is bound to four isocyanide ligands and also holds a lone pair of electrons. DFT calculations reveal that the dication is stabilized only by σ-donation from the four isocyanide ligands. Natural population analysis gives a charge of +0.74 on the Ge(ii) center, indicating that the positive charge is shared by the isocyanide substituents. [ABSTRACT FROM AUTHOR]

Single site homogeneous catalysts have been studied extensively in recent years as alternatives to traditional heterogeneous catalysts. The current theoretical study uses density functional theory to study the insertion process of the ethylene monomer into the titanium-carbon chain for contact ion-pair systems of the type [L 1 L 2 TiCH 3 -m-CH 3 -B(C 6 F 5 ) 3 ], where L 1 , L 2 , are Cp, NPH 3 , and other ligands. Different modes of approach cis and trans to the m-CH 3 bridge were considered. The counterion, B(C 6 F 5 ) 3 CH 3 - , was modeled by QM/MM methods. The value of DH tot -- the total barrier to insertion--was found to be positive (in the range of 4-15 kcal/mol). The ability of the ancillary ligands, L 1 and L 2 , to stabilize the ion-pair was found to be an important factor in determining the value of DH tot . On replacing the titanium metal center with zirconium, the DH tot values were found to be lowered (in the range of 2-9 kcal/mol), indicating that they would be better catalysts than their titanium analogues. The size of the ligands L 1 and L 2 was increased by replacing hydrogens in the ligands with tertiary butyl groups. The value of DH tot was found to increase (in the range of 10-28 kcal/mol) in contrast to the simple systems, for both the cis and trans cases of approach, with the cis mode of approach giving lower values of DH tot . Solvent effects were incorporated with cyclohexane (e = 2.023) as the solvent, and were found to have a minor influence, (0.5-1.5) kcal/mol) on the insertion barrier for all the cases studied. [ABSTRACT FROM AUTHOR]

Treatment of trans-[Ir(H)(N)2(iPr)4(POCOP)(DMAP)][BAr4f] (2) with H2 (1 bar) under ambient conditions (298 K) results in the formation of a trans-[Ir(H)(η2-H2)(iPr)4(POCOP)(DMAP)][BAr4f] (3) complex. Complex 3 exhibits H-atom site exchange between the bound H2 and the hydride ligands which are mutually trans to one another. A plausible mechanism of this exchange involves metal–ligand cooperativity as studied by computations. [ABSTRACT FROM AUTHOR]

Hydroformylation catalysis is the most important homogeneous catalysis process of the current day. The current computational investigation aims to understand the nature of the hydroformylation process when monodentate ligands are employed. The complete catalytic cycle for different monodentate ligands bound to the rhodium center has been studied with full quantum chemical calculations, with density functional theory (DFT). To the best of our knowledge, this is the first systematic investigation of the relative free energy surfaces for mono-coordinate monodentate and bi-coordinated monodentate ligands in hydroformylation catalysis. The results indicate that the barriers are lower for the mono-coordinate monodentate species in comparison to the bi-coordinate monodentate, for all the ligand cases studied, indicating higher activity for the mono-coordinate monodentate active species. [ABSTRACT FROM AUTHOR]