Three coordination in metal complexes

We report the evolution of electrical transport and grain size during the sintering of thin films spin-cast from soluble phosphine and amine-bound, chloride-terminated cadmium selenide nanocrystals. Sintering of the nanocrystals occurs in three distinct stages as the annealing temperature is increased: (1) reversible desorption of the organic ligands (≤150 °C), (2) irreversible particle fusion (200–300 °C), and (3) ripening of the grains to >5 nm domains (>200 °C). Grain growth occurs at 200 °C in films with 8 atom % Cl–, while films with 3 atom % Cl– resist growth until 300 °C. Fused nanocrystalline thin films (grain size = 4.5–5.5 nm) on thermally grown silicon dioxide gate dielectrics produce field-effect transistors with electron mobilities as high as 25 cm2/(Vs) and on/off ratios of 105 with less than 0.5 V hysteresis in threshold voltage without the addition of indium.

https://pubs.acs.org/doi/pdf/10.1021/nn502829s

Electrical transport and grain growth in solution-cast, chloride-terminated cadmium selenide nanocrystal thin films.

Uncommon co-ordinating agents—I: P,P,P′,P′-tetraethylethylenediphosphine☆

The reaction of Group 12 metal dihalides MX2 with the P,N-ligands [Fe(C5H4-PPh2)(C5H4-2-py)] (1) (2-py = pyrid-2-yl), [Fe(C5H4-PPh2)(C5H4-CH2-2-py)] (2) and [Fe(C5H4-PPh2)(C5H4-3-py)] (3) (3-py = pyrid-3-yl) was investigated. For a 1 : 1 molar ratio of MX2 and the respective ligand, three structure types were found in the solid state, viz. chelate, cyclic dimer and chain-like coordination polymer. The MII coordination environment is distorted pseudo-tetrahedral in each case. The P–M–N angle is much larger in the chelates (≥119°) than in the ligand-bridged structures (≤109°). 1 prefers the formation of chelates [MX2(1-κ2N,P)]. 3 forms coordination polymers [MX2(μ-3)]n. With the more flexible 2 all three structure types can occur. Dynamic coordination equilibria were observed in solution for the molecular complexes obtained with 1 and 2. NMR data indicate that the N- and P-donor sites interact most strongly with ZnII and HgII, respectively. While the formation of bis(phosphine)mercury complexes (soft–soft) was easily achieved, no bis(pyridine)zinc complex (borderline–borderline) could be obtained, which is surprising in view of the HSAB principle.

The coordination behaviour of ferrocene-based pyridylphosphine ligands towards Zn(II), Cd(II) and Hg(II).

Morpholine complexes of mercury(II) pseudohalides

228. The constitution of complex metallic salts. Part XI. The structure of the tertiary phosphine and arsine derivatives of cadmium and mercuric halides

H. S. Peiser

Papers

228. The constitution of complex metallic salts. Part XI. The structure of the tertiary phosphine and arsine derivatives of cadmium and mercuric halides