Chemistry of Specific Complexes

Extensive studies of several readily available vinylidene complexes have led to much interesting chemistry, many reactions being specific to the metal-ligand combination used. 

This complex is prepared in situ by intramolecular synchronous transfer of the a-H atom to R in TiR(CH=CH2)Cp 2 (R = Me, CH=CH2) to give methane or ethene, respectively. The corresponding r, N-C5Me4(CH2CH2NMe2) complex has also been described [347]. Thermal decomposition results in the formation of fulvene Ti (CH=CH2) r Ti -CH2C5Me4)Cp (26) [348]. Addition of HC CR (R= Pr, Bu , Ph, 

Cp [353]. The mechanism probably involves nucleophilic attack by phosphorus on Ca, followed by migration of Cl to the metal center with elimination of CO induced by the lone pair on P. Phospha-allene complexes W(r -RP=C=CHR )(CO)(NO)Cp (R = H, Ph R= Bu , Cy) are formed from phospha-alkenes RP=C(NMc2)2 [354]. Arsa-alkenes react similarly to give r -arsa-allene complexes W ri -RiAs=C=CHR )(CO)(NO)Cp [R R = Bu C(0)/Bu Fe(CO)2Cp/Bu Bu C(0)/ 

Thermolysis of Cr(=C=CMeR)(CO)5 (R=Bu, Pr) results in the formation of Cr2 p-(=C=CMeR) (CO)9 photolysis of this complex, or of M(=C=CMeR)(CO)s (M = Cr, W) directly, results in demetallation and formation of cyclobutane-1, 3-diones, by formal dimerization of the vinylidene/CO-coupled product pro-padienone [342]. 

Regiospecific cydoaddition of the C=C triple bond in alkynes MeC=CX (R = alkyl, aryl X = OEt, SMe, NMe2, NEt2) to the C=C double bond of the vinylidene in M 

---

The reader will want to consult a list of stability constants before selecting a specific complexing agent. The stability of specific complexes may be found in literature references such as Lange s Handbook of Chemistry or the CRC Handbook of Chemistry and Physics or the Handbook of Chemical Equilibria in Analytical Chemistry or NIST Critically Selected Stability Constants of Metal Complexes. ... 

A number of previous reviews have dealt with complexes of bpy and related ligands in various degrees of depth (89, 372, 552, 621, 753). Numerous other publications have dealt with aspects of the chemistry of bpy complexes specific mention should be made of those dealing... 

Many of the same techniques employed in studying the basic chemistry of coordination complexes can be be used in following the binding of transition-metal complexes to nucleic acids, but biochemical methods, with their often exquisite sensitivity, become valuable aids as well in delineating specific binding interactions. Tris(phenanthroline) metal complexes are particularly useful to illustrate this point, since here the metal center in the complex is selected in terms of the technique used for examination. 

A general account of preparative routes and of the chemical and physical properties of the metal-hydrogen system precedes the discussion of the specific chemistry of these complexes. 

There are a number of reviews that detail the various facets of alkylidyne chemistry, but the majority of these pre-date the enormous growth in the field that has been possible with the appreciation of the kinetic and thermodynamic stability conferred upon alkylidyne complexes by the inclusion of the bulky pyrazolylborate ligands. Furthermore, though a general overview of the chemistry of pyrazolylborate derivatives has appeared, there currently exists no comprehensive source of information specific to the chemistry of alkylidyne complexes co-ligated by poly(pyrazolyl)borates, a situation which this review attempts to... 

The yellow-red thiomolybdates, [MoOj.S4 J (x = 0-3), are formed in the reactions of molybdate with H2S or other sulfiding agents in basic aqueous solutions.The complexes are formed in sequence (x = 3 2 —> 1 — 0), with very specific reaction conditions and cations required for the isolation (often in impure form) of intermediate complexes. The crystal structures of many thiomolybdate salts have been determined, wherein the discrete dianions exhibit distorted tetrahedral or tetrahedral (for [MoS4] ) geometries, with Mo=0 and Mo=S distances of ca. 1.76 and 2.20 A, respectively. Authoritative reviews of the synthesis, properties and coordination chemistry of these complexes have been prepared by Muller and coworkers. Other articles cover more recent advances and applications in this area. ... 

Clearly, the coordination ability of an amino acid depends on its specific form, wifh carboxylate and amino groups, and the side chain each potentially coordinating. This feature in turn is critically dependent on the pH condition, ft is thus convenient to present the chemistry of lanthanide-amino acid complexes according to the pH conditions under which the synthesis is carried out. Specifically, the synthetic and structural chemistry of lanthanide complexes with amino... 

The nitrogen substitution chemistry of 2,3-dichloro-l,4-naphthoquiaone (30) has been widely employed (101). Although the product mixtures are sometimes complex, many examples illustrate the excellent results possible ia specific iastances eg, 3-nitro-12JT-ben2o[b]phenoxa2iae-6,ll-dione... 

---