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We present a free web application for the calculation of the buried volume (% V Bur ) of NHC ligands. The web application provides a graphic and user-friendly interface to the SambVca program, developed for the calculation of % V Bur values not only of NHC ligands but also of other classic organometallic ligands such as, for example, phosphanes and cyclopentadienyl-based ligands. To provide a reliable pro-

Developing more efficient catalysts remains one of the primary targets of organometallic chemists. To accelerate reaching this goal, effective molecular descriptors and visualization tools can represent a remarkable aid. Here, we present a Web application for analyzing the catalytic pocket of metal complexes using topographic steric maps as a general and unbiased descriptor that is suitable for every class of catalysts. To show the broad applicability of our approach, we first compared the steric map of a series of transition metal complexes presenting popular mono-, di-, and tetracoordinated ligands and three classic zirconocenes. This comparative analysis highlighted similarities and differences between totally unrelated ligands. Then, we focused on a recently developed Fe(II) catalyst that is active in the asymmetric transfer hydrogenation of ketones and imines. Finally, we expand the scope of these tools to rationalize the inversion of enantioselectivity in enzymatic catalysis, achieved by point mutation of three amino acids of mononuclear p-hydroxymandelate synthase

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N-heterocyclic carbene ligands IMes (1), SIMes (2), IPr (3), SIPr (4), and ICy (5) react with Ni(CO)(4) to give the saturated tricarbonyl complexes Ni(CO)(3)(IMes) (8), Ni(CO)(3)(SIMes) (9), Ni(CO)(3)(IPr) (10), Ni(CO)(3)(SIPr) (11), and Ni(CO)(3)(ICy) (12), respectively. The electronic properties of these complexes have been compared to their phosphine analogues of general formula Ni(CO)(3)(PR(3)) by recording their nu(CO) stretching frequencies. While all of these NHCs are better donors than tertiary phosphines, the differences in donor properties between ligands 1-5 are surprisingly small. Novel, unsaturated Ni(CO)(2)(IAd) (13) and Ni(CO)(2)(I(t)()Bu) (14) compounds are obtained from the reaction of Ni(CO)(4) with IAd (6) and I(t)()Bu (7). Complexes 13 and 14 are highly active toward substitution of the NHC as well as the carbonyl ligands. This has allowed the determination of Ni-C(NHC) bond dissociation energies and the synthesis of various unsaturated Ni(0) and Ni(II) complexes. Computational studies on compounds 8-14 are in line with the experimental findings and show that IAd (6) and I(t)()Bu (7) are more bulky than IMes (1), SIMes (2), IPr (3), SIPr (4), and ICy (5). Furthermore, a method based on %V(bur) values has been developed for the direct comparison of steric requirements of NHCs and tertiary phosphines. Complexes 8-14, as well as NiCl(C(3)H(5))(I(t)()Bu) (16) and NiBr(C(3)H(5))(I(t)()Bu) (17), have been characterized by X-ray crystallography.

Complexes of iridium bearing NHC (NHC ) N-heterocyclic carbene) ligands were synthesized and fully characterized. The series [(NHC)Ir(cod)Cl] were obtained by simple cleavage of [Ir(cod)Cl] 2 . The [(NHC)Ir(cod)Cl] complexes were reacted with excess carbon monoxide, leading to [(NHC)Ir(CO) 2 Cl]. The infrared carbonyl stretching frequencies of these were recorded to quantify the electronic parameter of NHC ligands. X-ray diffraction study results allow for determination of NHC steric parameters within this series. These data allow for comparison with other ligand families.

Aqueous Zn-ion batteries present a low cost, safe, and high-energy battery technology, but suffer from the lack of suitable cathode materials because of the sluggish intercalation kinetics associated with the large size of hydrated zinc ions. Herein we report an effective and general strategy to transform inactive intercalation hosts into efficient Zn 2+ storage materials through intercaltion energy tuning. Using MoS 2 as a model system, we show both experimentally and theoretically that even hosts with originally poor Zn 2+ diffusivity can allow fast Zn 2+ diffusion. Through simple interlayer spacing and hydrophilicity engineering that can be experimentally achieved by oxygen incorporation, the Zn 2+ diffusivity is boosted by 3 orders of magnitude, effectively enabling the otherwise barely active MoS 2 to achieve a high capacity of 232 mAh g -1 that is 10 times as its pristine form. The strategy developed in our work can be generally applied for enhancing the ion Experimental details and additional supporting data as noted in the main text (PDF).