Ultrafine gold nanoclusters (Au‐NCs) are susceptible to migrate and aggregate, even in the porosity of many crystalline solids. N‐heterocyclic carbenes (NHCs) are a class of structurally diverse ligands for the stabilization of Au‐NCs in homogeneous chemistry, showing catalytic reactivity in CO2 activation. Herein, for the first time, we demonstrate a heterogeneous nucleation approach to stabilize ultrasmall and highly dispersed gold nanoclusters in an NHC‐functionalized porous matrix. The sizes of gold nanoclusters are tunable from 1.3 nm to 1.8 nm based on the interpenetration of the metal‐organic framework (MOF) topology. Control experiments using amine or imidazolium‐functionalized MOFs afforded the aggregation of Au species. The resultant Au‐NC@MOF composite exhibits a steady and excellent activity in photocatalytic CO2 reduction, superior to control mixtures without NHC‐ligand stabilization. Mechanistic studies reveal the synergistic catalytic effect of MOFs and Au‐NCs through the MOF‐NHC‐Au covalent‐bonding bridges.

Cyclic voltammetry studies of two L(X)Ga-substituted dipnictenes [L(R2N)GaE]2 (E = Sb, R = Me 1; E =Bi; R = Et 2; L = HC[C(Me)NDipp]2; Dipp= 2,6-i-Pr2C6H3) showed reversible reduction events....

We report on the structures of three unprecedented heteroleptic Sb-centered radicals [L(Cl)Ga](R)SbC (2-R,R= B[N(Dip)CH] 2 2-B,2 ,6-Mes 2 C 6 H 3 2-C,N (SiMe 3 )Dip 2-N) stabilized by one electropositive metal fragment [L(Cl)Ga] (L = HC[C(Me)N(Dip)] 2 ,Dip = 2,6-i-Pr 2 C 6 H 3 )and one bulky B-(2-B), C-(2-C), or N-based (2-N)substituent. Compounds 2-R are predominantly metal-centered radicals.T heir electronic properties are largely influenced by the electronic nature of the ligands R, and significant delocalization of unpairedspin density onto the ligands was observed in 2-B and 2-N. Cyclic voltammetry (CV) studies showed that 2-B undergoes aq uasi-reversible one-electron reduction, whichw as confirmed by the synthesis of [K([2.2.2]crypt)][L(Cl)GaSbB[N-(Dip)CH] 2 ]( [K([2.2.2]crypt)][2-B]) containing the stibanyl anion [2-B] À ,w hich was shown to possess significant SbÀB multiple-bonding character.

A combined experimental and computational study demonstrates the influence of fluorine substituents on the electronic properties of β-diketiminate ligands.

The hydrogenation, and competitive hydrogenation, of toluene, ethylbenzene, propylbenzene and the xylenes has been studied over a rhodium catalyst in the liquid phase at 323 K and 3 barg. The reactivity of the aromatics gave an order of para-xylene > ortho-xylene > metaxylene > toluene > ethylbenzene >> propylbenzene. Kinetic analysis revealed that the order of reaction in hydrogen was typically first order while the reaction order in toluene was zero order and negative half order for ethylbenzene. The reaction order for propylbenzene and the xylenes was negative first order. Apparent activation energies were calculated and all were in the range 26-46 kJ.mol -1 . Competitive hydrogenation between toluene, ethylbenzene and propylbenzene revealed that the propylbenzene was the most strongly adsorbed aromatic in agreement with the strongly negative reaction order. The xylenes gave an order of reactivity of para > ortho > meta following the increasing negative reaction order. Reactions with deuterium revealed an inverse kinetic isotope effect, most likely related to the change in hybridization of the carbon from sp 2 to sp 3 , for all reactions, except that of ortho-xylene.