Leslie Mcintosh (onionstore6)
Moreover, SCO complexes undergo notable structural changes upon transition, so intra- and inter-molecular interactions might play an important role in stabilizing either spin state. As a consequence, the U parameter depends strongly on the dispersion correction scheme that is used. In this paper, we parametrize U for nine reported SCO compounds (five based on FeII, 1-5 and four based on FeIII, 6-9) when using the D3 and D3-BJ dispersion corrections. We analyze the impact of the dispersion correction treatments on the SCO energetics, structure, and the unit cell dimensions. The average U values are different for each type of metal ion (FeIIvs. FeIII), and dispersion correction scheme (D3 vs. D3-BJ) but they all show excellent transferability, with mean absolute errors (MAE) below chemical accuracy (i.e. MAE less then 4 kJ mol-1). This enables a better description of SCO processes and, more generally, of spin state energetics, in materials containing FeII and FeIII ions.In a preliminary study [Phys. Chem. Chem. Phys., 2017, 19, 15247], we have recently documented an elusive mechanism underlying the cluster formation in model fluids with microscopic competing interactions (hard-sphere two-Yukawa). This mechanism consists in a tiny rearrangement of a distant correlation peak in the local density profile. For weak attractions, this peak contributes to the shallow, long-wave oscillation typical of such fluids; as the attraction strengthens, such a portion progressively disengages from the long-range behaviour, and moving backwards takes on the character of a new shell of neighbours, falling beyond the existing ones at shorter distances. This "reversal of trend" - despite its tiny size, in comparison with the overall aspect of the density profile - is shown to precisely occur at the onset of clustering. The scope of the present study is twofold. In the first instance, we positively assess our preliminary finding. To this aim we have studied by Monte Carlo simulations different families of two-Yukawa fluids, under the same conditions investigated in the original paper, namely fixed temperature, high fluid-density and increasingly attractive strength. selleck kinase inhibitor Apparently, the reversal of trend in spatial correlations sets as a sensitive criterion to identify the clustering threshold, complementing other common indicators, based on the modifications undergone by the low-wavevector peak in the structure factor. Secondly, we document the accuracy of the Hypernetted Chain theory in predicting the spatial rearrangement under scrutiny. This evidence paves the way to an extended investigation of the observed phenomenology by the complementary use of theoretical and simulation tools.We report the synthesis and characterization of a series of original tantalum/rhodium heterobimetallic species assembled by a bifunctional alkoxy-N-heterocyclic carbene (NHC) ligand platform (noted L). The heterotrimetallic [Ta(CH2tBu)(CHtBu)(μ-L)Rh2(COD)2Cl2]n, 2, and heterobimetallic [Ta(μ-L)(CHtBu)(CH2tBu)2Rh(COD)Cl], 4, complexes are obtained upon treatment of [Ta(L)(CHtBu)(CH2tBu)2], 1, with [Rh(COD)Cl]2. To avoid parasistic reactivity arising from the neopentylidene fragment in 1, the peralkyl compound Ta(L)[OSi(OtBu)3](CH2tBu)3, 5, resulting from the 1,2-addition of tris(tertbutoxysilanol) across the Ta[double bond, length as m-dash]C alkylidene motif, is prepared. An unanticipated silanol-NHC adduct, HOSiOtBu3Ta(L)[OSi(OtBu)3](CH2tBu)3, 6, is formed when 1 is treated with two equivalents of HOSi(OtBu)3. Finally, treatment of 5 with [Rh(COD)Cl]2 provides the heterobimetallic complex Ta(μ-L)[OSi(OtBu)3](CH2tBu)3Rh(COD)(Cl), 7, in high yield. This work highlights the reactivity of Ta-NHC adducts and the aptitude of the NHC motif to transfer from Ta to Rh which is used with profit as an efficient synthetic route to access early/late heterobimetallic complexes.σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl r
