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New, stable heterobidentate phosphane-olefin ligands based on the dibenzo[b,f]phosphepine backbone are reported together with their redox properties and coordination chemistry to rhodium(I). The X-ray crystal structures and DFT calculations show different conformations for the P-phenyl (6a) and P-mesityl (6b) derivatives. Cyclic voltammetry (vs Fc/Fc(+)) of 6a supported by UV-vis spectroelectrochemistry showed two cathodic waves, a reversible one at E-1/2 = -2.62 V (I-f/I-b, = 1.0) and a quasi-reversible (I-f/I-b approximate to 1.2) one at E-1/2 = -3.03 V. Reduction with sodium afforded a mixture of the radical anion [6a(center dot)](-), characterized by EPR spectroscopy, and dianion [6a](2-), for which an X-ray crystal structure was obtained. Both 6a and 6b bind to Rh-1 centers, giving rise to 3:1 (8a) and 2:1 (8b) ligand:Rh complexes, respectively. Two dibenzo[b,f]phosphepines in 8a and 8b act as heterobidentate ligands in which both the phosphorus atom and the olefinic double bond coordinate to rhodium, but the third ligand in 8a binds as a monodentate P-donor. The cyclic voltammogram of 8b showed two close-lying waves, a one-electron reversible wave at -1.45 V and a two-electron quasi-reversible wave at -1.80 V (I-f/I-b approximate to 1.3). 8a showed a reversible wave at -1.71 V and irreversible waves at lower potentials.

The 3D distribution of nanocrystals at the liquid-air interface is imaged for the first time on a single-particle level by cryogenic electron tomography, revealing the equilibrium concentration profile from the interface to the bulk of the liquid. When the surface tension of the liquid is decreased, the interaction of the nanocrystals with the liquid-air interface shifts from adsorption to desorption. Macroscopic surface tension measurements do not detect this transition, due to the presence of surface-active molecular species.

The 3D distribution of nanocrystals at the liquid-air interface is imaged for the first time on a single-particle level by cryogenic electron tomography, revealing the equilibrium concentration profile from the interface to the bulk of the liquid. When the surface tension of the liquid is decreased, the interaction of the nanocrystals with the liquid-air interface shifts from adsorption to desorption. Macroscopic surface tension measurements do not detect this transition, due to the presence of surface-active molecular species.