Bonding Effects of Ligands

Let us consider AL (n= 1,2,3,. . . ) systems in which L refers to a ligand, an atom or a group, that contains more than just a single s orbital. In most cases, L contributes one electron in a sigma fashion to A as shown in 9.14 for planar AL3. The hybrid 

H2A-L when a second-row A atom is present. For the case of the heavier A atom, although the energy gap Ae between and (pa is small, the (n (pa) overlap is small too because of the longer A—L bond and more diffuse valence orbitals. In addition, recall that the inversion barrier of AH3 is much larger for a second- 

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B. Eight-Electron Systems, 143 TT-Bonding Effects of Ligands, 145 Shapes of AII4 Systems, 148... 

Closely related mixed amido/imido/guanidinato tantalum complexes of the type Ta(NR R )[(R R2N)C(NR )2]( = NR ) (R R = Me, Et R = Cy, Pr R = Pr", BuO were synthesized by the insertion of carbodiimides into to tantalum-amide bonds in imidotantalum triamide precursors, and the effects of ligand substitution on thermal properties were studied by TGA/DTA measurements. In addition, selected compounds were pyrolyzed at 600 °C and the decomposition products were studied by GC-MS and NMR spectroscopy. ... 

In Section ILEA, I shall discuss and correlate various factors that could be involved in promoting the Co—C bond homolysis in biological systems. First, I wish to focus on two structural features and their relationship to Co—C BDE. The first factor is the effect of ligand basicity and steric bulk on Co—C BDE. In a series of (pyridine)Co(Hdmg)2R compounds, Halpem et al. [90] found that the Co—C BDEs (kcal moC1) increased with the basicity of the pyridine ... 

J. Rosenqvist, K. Axe, S. Sjoberg, and P. Person, Adsorption of dicarboxylates on nano-sized gibbsite particles effects of ligand structure on bonding mechanisms, Colloids Surf. A 220, 91-104(2003). 

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