Group 6 organometallic complexes

The participation of siloxane groups in the reaction increases with the temperature of dehydration of Si02 and quantity of organometallic compound introduced in the reaction. According to the data of infrared spectroscopy (139), the allyl ligands formed in the surface organometallic complexes of Ni and Cr keep the 7r-allyl character of the metal-ligand bond. 

Over a decade on, this area is now beginning to reach maturity, with some of the early new developments subjected to intensive research and now consolidated. New areas have been opened up, for example, organometallic complexes of group. T... 

The field of transition metal complexes of isocyanides developed slowly over more than a century to a respectable subarea in coordination chemistry, and in the process seems to have attracted very little attention. Even the remarkable resurgence of transition metal organometallic chemistry in the last 20 years, and the realization that isocyanides and carbon monoxide should be quite similar as ligand groups in organometallic complexes, did not initiate an extensive development of this area of chemistry. Only in the last several years has this potentially important subject begun to receive the attention it would seem to deserve. 

Organometallic complexes containing Group IIIB and Group IVB ligands 115a... 

An organometallic complex consists of a central metal atom and a munber of Hgands, which can be schematically classified into three groups ... 

Anchored organometallic complexes of tungsten were prepared by the interaction of W(C4H7)4 with surface OH groups, and the resulting surface species play a role as precursors for the synthesis of different surface tungsten compounds (Scheme 7.11).231... 

The reaction of silica-supported bis(allyl)Rh complexes with PMe3 followed by hydrogen treatment leads to the synthesis of the surface SiO-RhH2(PMe3)4+ as the first example of a cationic organometallic complex attached to the silica surface by ion pairing. The counterion is presumed to be a siloxy group SiO- on the silica surface.276 277... 

Various organometallic complexes containing heterocyclic group 15 rings are known. These are often formed in complex reactions. For example, a mixture of the phosphacyclopentadienes 111 and 112 reacts slowly with distilled calcium metal to yield the tetranuclear 113 (Figure 58).301 The centra symmetric Ca2Cl2 core is nearly square, with... 

Recent Trends in Polymerization Catalyzed by Organometallic Complexes of Transition Metals Other than Those of Group 4... 

Similar isolobal and isoelectronic relationships [234, 235] have recently been observed for various organometallic complexes of both Group 5 metals... 

---