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Ji-accepting ligand

Some carbyne complexes, in particular cationic ones with good Ji-accepting ligands, can react with nucleophiles to give carbene complexes [187,521]. Several reductions of carbyne complexes to carbene complexes by treatment with metal hydrides have been reported. Similarly, organolithium or other carbanionic reagents can react with electrophilic carbyne complexes to yield carbene complexes. Illustrative examples of both reactions are sketched in Figure 3.23. [Pg.94]

Carbon monoxide and the cyanide ion are believed to greatly stabilize the transition state because they are Ji-accepting ligands. A ligand with jt acceptance capability can remove electron density from the metal atom, stabilizing the transition state. The order of jr-bonding ability is... [Pg.123]

There are several parallels between the chemistries of the carbene and carbyne ligands. The classification of carbyne complexes into two major structural types—Fischer and Schrock—is perhaps the most obvious of these parallels. Complex 64 represents the prototypical Fischer carbyne complex Ccarbyne bonded to a low-valent metal with Ji-accepting CO ligands attached. Structure 65, on the other hand, is a classic example of a Schrock carbyne complex because a high-valent metal is present with electron-donating ligands attached. Atoms attached to Ccaibyne helpful in distinguishing between Fischer and Schrock carbene complexes (i.e., heteroatoms for the former and H and C for the latter), are less important in the case of carbyne complexes. It is convenient to classify carbyne complexes... [Pg.440]

Significant quadratic hyperpolarizabilities for two mixed-valence bimetallic complexes have also been reported [13, 19] for example complex 77 is characterized by a oe(Stark) of 37 x 10 ° esu [200]. In such NLO chromophores, the electron-accepting Ru center is stabilized by strongly basic amine ligands, whilst the electron-donating (f Ru is stabilized by Ji-accepting cyanides. [Pg.44]

You will sometimes see Ji compiexes drawn with simpler dotted lines going to the middle of the % bond, sometimes with dotted it bonds, and sometimes with bonds simple or dotted) going to the ends of the old it bond. These are all acceptable as the bonding is complex as you will see. We might almost say that the ambiguity Is helpful we often don t know either the exact nature of the bonding or the number of other ligands in the complex. In the... [Pg.1313]

The term organometallic describes precursors which contain a direct metal-carbon interaction, be it a or Ji in nature. This is in parallel with traditional chemical nomenclature. Metalorganic, in contrast, now is accepted widely as the description for any metalorganic containing ligand precursor for CVD. This includes, for example, metal alkoxides and metal amides. The metal carbonyl work of Mond, last century, is one early example of OMCVD. [Pg.6]

Quasi-relativistic Xa-scattered wave calculations on CpyAn-L compounds with L=H, CO, NO, OH, led to the conclusion that sigma bonding to the Ji-neutral, jr-acidic, and jt-basic ligands has essentially the same donation of electron density from the sigma orbital of the L ligand into a uranium orbital that is primarily 6dz2 in character. The 5f orbitals are responsible for back donation into the Ji orbitals of CO and NO. Acceptance of electron density from the n orbitals of OH involves the 6d orbitals (Bursten et al. 1989). [Pg.278]


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