Phosphines ammines

The complexes [RuL3] (LH = tropolone, a-isopropenyltropolone) have been prepared by reaction of RuC13 with LH in the presence of NaHC03 the NMR spectra of these products show them to have predominantly the mer configuration.2095 Ketoenolate complexes incorporating phosphine, ammine and amine ligands are discussed in Sections 45.5, 45.4.1 and 45.4.2 respectively. 

In this section we consider unsubstituted complexes first, then aqua, hydroxo, halo, carbonyl and phosphine ammines. For nitrido ammines see pp. 562, 563, nitrosylammines p. 546, and dinitrogen ammines p. 554. Other substituted ammines are dealt with under the section concerned with the substituting ligand. 

Ruthenium(IT), d A wide range of Ru complexes incorporating carbonyl, phosphine, ammine and heterocyclic ligands are known. Virtually all Ru complexes are octahedral and diamagnetic with a l2g configuration (unless steric constraints are present). Catalytic processes utilizing Ru" phosphine complexes, kinetic studies on substitution reactions of [Ru(NH3)5L] " and the photophysics and photochemistry of [Ru(bipy)j] and related systems have been areas of major advance in recent years. 

Within the osmium complexes in oxidation states (II-IV) [11,12] the stability of the +4 oxidation state becomes more important. Ammine and tertiary phosphine complexes have been selected for detailed examination. 

The soft Au+ forms relatively few complexes compared with those of phosphines. Complexes with ammines, nitriles and diazoles like Au(NH3)2 and Au(RCN)2 are known but little studied. In linear Au(NH3)2, Au-N is 2.01-2.03 A [70a], [Au(NCPh)2]+ has been used as a labile source of other gold complexes [70b]. AuCl(piperidine) is a monomer with weak tetra-meric association in contrast AuX(py) (X = Cl, Br, I) are [Aupy2]+[AuX2] with a chain structure in the solid state (and Au-Au interactions), suggesting a close balance between factors for molecular and ionic structures [70c] (note also the tetrahydrothiophene complexes in section 4.10.6). 

Table 4.22. Geometrical and NBO parameters for ammine, phosphine, and carbonyl coordination complexes of Os and Re hydrides, showing bond angles, valence Lewis accuracy (%p ), and metal bond hybrid (Iim) and polarization (%cm2) of oml and omh NBOs...

Phosphine complexes are generally regarded more electron-rich than the corresponding ammine complexes, and which pathway is preferred under these electronic conditions has also been investigated. For trans-PtCl2(PH3)2, oxidative addition has been calculated to be much more favorable than the electrophilic pathway for the activation of methane... 

Ammonia is slowly absorbed by the triiodide and a voluminous yellow substance is produced8 which, if kept over sulphuric acid, loses ammonia until the composition corresponds with the tetrammino-triiodide, AsIg.ANHg. At 0° C. more ammonia can be absorbed to yield the dodecammino-compound, AsI3.12NH3. If ammonia is passed into a solution of the triiodide in benzene or ether, a voluminous white precipitate, of composition 2AsI3.9NH3, is formed.8 The existence of these ammines as definite compounds has not been established.10 With phosphine, arsenic phosphide is produced ... 

Room temperature emission has been observed for a number of transition metal complexes. Examples include Rh111 ammines,53 [Pt(CN)4]2-,54 and some Cu1 phosphine complexes.55 An important class is that of the polypyridine complexes of Ru11 and related species.56 This last emission, probably from a 3CT state, is quite strong and its occurrence has made possible a number of detailed studies of electron transfer quenching reactions. 

Fig. 7. Optimized structures of complexes 3-6 [C, point group symmetry, M=Fe,Ru]. Structural data are given for two Fe(II) complexes for which experimental data are available for comparison, i.e., for Fe(II)—3 (67,68), Fe(II)—5 (with PPr3 [1st exp. value] and PEt3 [2nd exp. value] phosphines) (70) and for Ru(II)—6 (with Me instead of H at the chelate-ammine group) (112).

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