Transition metal complexes divalent

Figure 8-16. Correlation of ionic radius and LFSE with log values for divalent transition-metal complexes of 1,2-diaminoethane.

Stevenson F.J. Nature of divalent transition metal complexes of humic acids as revealed by a modified potentiometric titration method. Soil Sci 1977 123 10-17. 

Abstract The theoretical and experimental research on carbodiphosphoranes C(PR3)2 and related compounds CL2, both as free molecules and as ligands in transition metal complexes, is reviewed. Carbodiphosphoranes are examples of divalent carbon(O) compounds CL2 which have peculiar donor properties that are due to the fact that the central carbon atom has two lone electron pairs. The bonding situation is best described in terms of L C L donor acceptor interactions which distinguishes CL2 compounds (carbones) from divalent carbon(ll) compounds (carbenes) through the number of lone electron pairs. The stmctures and stabilities of transition metal complexes with ligands CL2 can be understood and predictions can be made considering the double donor ability of the carbone compounds. 

Transition Metal Complexes with Heterocyclic and Cyclic Divalent Carbon(O)... 

Table 2 shows those double ylides or related compounds for which transition metal complexes A CL2 or A CLL are known. A more detailed description of the divalent carbon(O) compounds in Table 2 which act as ligands in transition metal chemistry are given in the following sections. 

The number of theoretical investigations of transition metal complexes with carbodiphosphoranes and related divalent carbon(O) ligands is rather small. Quantum chemical calculations of the nickel complexes (CO) Ni-C(PPh3)2 with n = 2, 3 have been pubhshed together with experimental work which describes the S3mthesis and X-ray structure analyses of the compounds [107]. The first systematic... 

In this section we review experimental work about transition metal complexes bearing divalent carbon(O) ligands [M]-CL2. 

Diebold, A., Elbouadili, A., and Hagen, K.S. Crystal structures and solution behaviour of paramagnetic divalent transition metal complexes (Fe, Co) of the sterically encumbered tridentate macrocycles l,4,7-R3-l,4,7-triazacyclononane coordination numbers 5 (R = i-Pr) and 6 (R = /-Bu), Inorg. Chem. 39 (2000), 3915-3923. 

Extending this approach, using hexacyanometalate building blocks together with divalent transition metal complexes containing labile positions has afforded a variety of one-, two- and three-dimensional compounds with very different physical properties from those of the face-centred Prussian blues [20-22],... 

Tin(II) can act as a donor. Complexation of various divalent tin compounds by Lewis acids has been realized, many in transition metal complexes, e g. (15) and (16), but also with main group Lewis acids, e g. (16). 

It seems worthwhile to investigate whether or not the arylpentazoles form transition metal complexes, for example of type (7). These could be converted into pentazole complexes (8) without destruction of the pentazole system. Unsubstituted pentazole (1) would be expected to be a strong acid with a highly aromatic anion (6) which could possibly form ferrocene analogs such as M (N5)2, where M" represents a divalent metal ion. Unfortunately, it has not been possible to investigate the properties of unsubstituted pentazoles, since neither... 

W. Petz, Transition Metal Complexes with Derivatives of Divalent Silicon, Germanium, Tin, and Lead as Ligand", Chem. Rev. 1986, 86, 1019. 

The subject of heterolytic activation of Hj by transition metal complexes has been critically reviewed. Equation (a) illustrates the heterolytic splitting of Hj by a divalent metal complex. Ligand X is typically anionic, and the reaction involves a net substitution... 

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