Metal complexes M

Section 14 14 Transition metal complexes that contain one or more organic ligands offer a rich variety of structural types and reactivity Organic ligands can be bonded to a metal by a ct bond or through its it system Metallocenes are transition metal complexes m which one or more of the ligands is a cyclopentadienyl ring Ferrocene was the first metallocene synthesized Its electrostatic potential map opens this chapter... 

Multiple state emission and related phenomena in transition metal complexes. M. K. DeArmond and C. M. Carlin, Coord. Chem. Rev., 1981, 36, 325-355 (89). 

Base hydrolysis in transition-metal complexes. M. L. Tobe, Adv. Inorg. Bioinorg. Mech., 1983, 2,1 (269). 

Scheme 29 Acute coordination angles and atomic polarization in metal complexes [M(CO)j]...

Combinatorial methods in catalysis by metal complexes (M.T. Reetz)... 

Figure L Modified Latimer diagram illustrating the relative reduction potentials of a metal complex (M) and its excited state (M ).

The dithiophosphonic acid monoesters, RP(OR )(S)SH can be conveniently prepared by cleavage of dimeric, cyclic diphosphetane disulfides, [RP(S)S]2 with alcohols, silanols, or trialkylsilylalcohols180 and then can be converted into metal complexes M[SPR(OR )]2 without isolation.181 The substituted ferrocenyl anion, (N3C6H4CH20)(CpFeC5H4)PS2 has been prepared in two steps from P4Sio, ferrocene and hydroxymethylbenzotriazole (and its salt was used for the preparation of some nickel and rhodium complexes).182 Zwitter-ionic ferrocenylditiophosphonates,... 

Keywords Allylic Alkylation m Asymmetric Catalysis m C2-Symmetry m De-symmetrization m Electronic Differentiation m Heck Reaction m Hydrogenations m Metal Complexes m Modular Design m P,N-Ligands m Steric Differentiation m Respective Control... 

However, for Group Ylb transition metal complexes (M = Cr, Mo, and W) in basic solution, their studies led them to propose a different type of catalytic cycle involving the decomposition of formate intermediate.25,33,54 Below (Scheme 18a) is an example for Mo, but one can readily replace Mo with Cr or W. 

Contents K. Bemauer Diastereoisomerism and Dia-stereoselectivity in Metal Complexes M. S. Wrighton Mechanistic Aspects of the Photochemical Reactions of Coordination Compounds. 

The rate law governing substitution in planar complexes usually consists of two terms, one first-order in the metal complex (M) alone and the other first-order in both M and the entering ligand Y ... 

Figure 8. Dependence of the BOD-catalyzed oxygen reduction current density on the difference in formal potentials between the O2/H2O couple and a range of cyano-metal complexes (M) for three values of solution pH. Arrows indicate reported values of the BOD formal potential F (Enz) relative to that of O2/H2O. Reproduced with permission from ref 159. Copyright 2003 Elsevier Science B.V.

The majority of transition metal complexes [M]-CL2 are known with C(PPhs)2 as ligand CL2 while the coordination ability of other symmetrical carbodiphosphoranes remains unexplored as yet. General preparation methods to introduce this ligand consists in a reaction between the free double ylide and a transition metal complex with a labile bonded ligand or compounds with a vacant coordination site. 

Figure 1.4. Chiral environment of an (i )-BINAP-transition metal complex (M = metallic element, ax = axial, eq = equatorial = coordination site in the plane ...

To obtain information on the coupling of the various intermediates one has to analyze the relationship between the corresponding titration curves. Scheme 3.4-3 shows typical steady-state curves for the (1) stepwise twofold association of ligand L with metal complex M, (2) association of L with two metal complexes M and N at equilibrium and (3) association of L to two metal complexes M and N being not at equilibrium (kinetically separated). From these three types of coupling most of the partial maps can be easily interpreted. 

Table 9 Stereochemical Parameters for Some Octahedral Transition Metal Complexes, [M(unidentate...

Figure 4.71 (a) General structure of a metal complex M is the metal centre (which is in general an ion) and L is a ligand, (b) Some examples of inorganic and organic ligands... 

Figure 4.75 Schematic representation of the charge transfer in various excited states of a metal complex. M is the metal centre and L stands for a ligand. LF is a ligand field transition, CTs are the charge transfer transitions, LL is an intraligand transition, and CTTS is a charge transfer to solvent...

The metal complexes of diethyl dithiophosphate were first investigated in 1931,134 when it was shown that the transition metal complexes [M((EtO)2PS2 ] (n = 2 or 3) were similar to those of xanthates and dialkyl dithiocarbamates, containing a four-membered XSMS (X = C or P) ring. A... 

Table t Dipole Moments (jif and Relaxation Times (t) of Square-planar Metal Complexes [M(RCS—CHCOR lil... 

Table 5 Dipole Moments ps (D) of Square-planar and Tetrahedral Metal Complexes [M(RCS=CHCOCF,),]...

Table 6 Dipole Moments pi, (D) of Octahedral Metal Complexes [M(RCS=CHCOCF3)1]...

The qualitative operation of Marcus theory can be illustrated most easily by considering how it might estimate the rate constant for electron transfer between two metal complexes M and N. If we assume M and N to be structureless spheres, the first step leading to electron exchange involves diffusion of the two reagents toward each other, either aided or impeded by electro-... 

We use relativistically optimized geometries throughout. (See, e.g., ref. (52) for an example of the optimization procedure that was used for the uranium compounds.) The transition metal complexes M(CO)6 and [MO4]2-, M = Cr, Mo, W, are the only exception experimental geometries have been used in these cases (7). 

Metal-catalysed hydrolysis of / -nitrophenyl picolinate at pH 7.5 was in the order Cu(II) > Ni(II) > Zn(II) > Co(II) > La(III). The probable mechanism is via attack by external HO- on the metal-ion complex (80).80 High catalytic activity in the hydrolysis at pH 7 of p-nitrophenyl picolinate, but not / -nitrophenyl acetate, was displayed by the metal complexes M(2-aminopyridine)2(OAc)2 (M = Zn, Ni), showing that they were good models for hydrolytic metalloenzymes.81... 

The concept has been extended to the C-H activation of nitriles, which coordinate strongly with metals. As shown in Scheme 3, coordination of a nitrile to low-valent metal complex (M) would increase both the basicity of the metal complex and the acidity of the C-H bond adjacent to the nitrile, and hence oxidative addition of the metal into the a-C-H bond of the nitrile would occur readily to afford an a-cya-noalkyl metal hydride complex (7), which undergoes isomerization to a N -bonded nitrile complex (8). The reaction of 8 with an C-electrophile forms a carbon-carbon... 

IV Electron transfer reactions of free radicals and metal complexes, including reactions of R with M +, e.g., oxidation by Cu2+ or reduction by Cr2+ (considered to be outside our scope unless M>+ represents an organometallic compound), and reactions of RMgX with transition metal complexes m, 129... 

For this purpose, a series of Frechet-type polyether dendrons of zeroth-to third-generation containing an NCN-pincer metal complex (M = Pt, Ni) at the focal point of the wedge were prepared [69]. Their synthesis was either... 

React with metal complex M (side-chain selective)... 

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