Ligands weakly coordinating

RuCl2(PPh3)2 reacts with 4-R2P-dibenzothiophene (R = Ph, p-Tol) and forms 303, in which the dibenzothiophene ligand is coordinated to ruthenium via the phosphorus and sulfur atoms [84JA5379, 87JOM(318)409]. The donor ability of the sulfur atom is relatively weak. Complex 303 (R = Ph) is able to add carbon monoxide and yield the monocarbonyl adduct. 

With a tridentate ligand Au(terpy)Cl3.H20 has, in fact, AuCl(terpy)2"1" with weakly coordinated chloride and water while Au(terpy)Br(CN)2 has square pyramidal gold(III) the terpyridyl ligand is bidentate, occupying the axial and one basal position [124]. Macrocyclic complexes include the porphyrin complex Au(TPP)Cl (section 4.12.5) cyclam-type macrocyclic ligands have a very high affinity for gold(III) [125],... 

N,N -Chelation is also exhibited by the dianionic P(III)/P(V) ligands (25) in the MejSn complex (31) [39] and in the magnesium complex (32) [40], which is prepared by oxidation of [Mg(thf)2[ BuNP(p-N Bu)2PN Bu] by elemental tellurium [40]. One of the endocychc N Bu groups in (32) is also weakly coordinated to magnesium, thus providing an intramolecular base-stabihzation similar to that observed for complexes of type (8). 

When the reaction is carried out in heptanol [61], the particles are monodisperse in size (3 nm), well dispersed in the solvent, and adopt the hep structure of bulk rutheniiun. They can be isolated and re-dissolved in various solvents, including d -THF for NMR analysis. In this case, it is clear that coordinated heptanol is present at the surface of the particles and acts as a weakly coordinating ligand. In this case, the presence of surface hydrides was demonstrated by NMR techniques. 

Finally, the term steric stabihzation coifid be used to describe protective transition-metal colloids with traditional ligands or solvents [38]. This stabilization occurs by (i) the strong coordination of various metal nanoparticles with ligands such as phosphines [48-51], thiols [52-55], amines [54,56-58], oxazolines [59] or carbon monoxide [51] (ii) weak interactions with solvents such as tetrahydrofuran or various alcohols. Several examples are known with Ru, Ft and Rh nanoparticles [51,60-63]. In a few cases, it has been estab-hshed that a coordinated solvent such as heptanol is present at the surface and acts as a weakly coordinating ligand [61]. 

To compare NEt3 with NOct3, there was no obvious effect to regulate the size distribution of nanoparticles, because they could not function as a capping ligand of nanoparticles due to their weak coordination to silver in the growth process of silver nucleus [17]. 

The intermediate-spin ground state of the ferric compounds published by Jager and coworkers is also stabilized by a N4-macrocyclic ligand, [N4] which exist in different varieties of substitutions. The apical ligands are weakly coordinating halides or pseudohalides, such as iodide in the case of [Fe [N4]l] (20) [68]. The electronic structure was elucidated by EPR, Mbssbauer and DFT studies. 

Most of the (phosphine)gold(III) complexes known in the literature have a square-planar stereochemistry. They are generally stable and can be prepared by two methods oxidation of the corresponding gold(I) complexes, or substitution processes of weakly coordinated ligands. 

Again, weak coordination is expected for ether ligands to zinc, however, the larger number of structurally characterized examples is at least partially attributable to the frequent use of solvents such as diethyl ether or tetrahydrofuran which may provide additional ligands to the metal center. 

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