Carboxylate and Related Complexes

2 Carboxylate and Related Complexes. - The IR spectra of Mg(02CCH3 C1 )2(L)2, where n = 1-3, L = 3-propylcarbinol, suggest that the carboxylate ligands are unidentate for n = 1 or 3, but bridging for n = 

There is IR evidence for bridging carboxylates in titania hydrolysates in the presence of carboxylic acids. The IR spectra of V0(quin)(H20)3 and [V0(quin)2S04], where quin = quinic acid, (56), include Vs and Vas CO2 showing unidentate carboxylate. The sulfato complex gave bands from unidentate sulfate.  

IR bands due to surface formate complexes were seen when CO2 is adsorbed on Si02-supported RhM, where M = Cr, Mo or W, catalysts. The complexes [MM (ox)(NCS)g] -, where MM = CP Fe ox = oxalato, 

The first mononuclear manganese citrate complexes have been prepared [Mn XC6Hs07)2] and [Mn XC6H407)2]. Both give IR bands consistent with unidentate carboxylato coordination. VCO2 modes in [CaM(mal)2(H20)4], where M = Mn, Fe, Co or Ni, mal = malonato, are all consistent with bridging carboxylato groups.  

The complexes trans-Fe(dmpe)2(OCHO)(L), where L = H or OCHO, both have vC02 bands of unidentate formate ligands (Vg near 1320 cm Vas near 1605 

2 Carboxylate and Related Complexes - FTIR and FT Raman spectra of aqueous solutions of alkah metal oxalates gave evidence for varying degrees of M -oxalate association. FTIR data were reported on coordination of side-chain COO groups to Ca in equine lysozyme, which leads to characteristic shifts in both Vs and VasC02. There is FTIR evidence for coordination of COO groups (of aspartine) to Ca in bovine a-lactalbumin.  

CO adsorbed on Cr03/Si02 gives IR bands due to (among other species) a unidentate carbonate. The IR spectrum of [CrW304(0Ac)s] shows the presence of bridging bidentate acetato between Cr and W. [Cr2(ox)5j , where ox = oxalato, gives IR bands due to both bidentate (1700 cm , VasCO 1678 

Bands due to CO2 for [Cr2(p-0H)n(p-RC02)3 n(bispma)2], where bispma = bis(2-pyridylmethyl)amine, n = 1 or 2, R = H, Me, Et, CH2CI, CH2CICH2, confirm the bridging nature of the carboxylate groups.  

CO2 bands show changes in width which can be related to electron localisation and delocalisation in [M30(00CCMe3)6py3] , where M = Mn or Fe. The unidentate catecholate hgand in Re0[0(0H)C6H4] S2CNEt2 is shown by the presence of OH at 3489 cm in the IR spectrum.  

IR data for [Pd(OAc)2(Me2SO)]2 contain bands for both bridging and terminal acetato groups. Complex (69), where A2 = (NH3)2, en, etc.-, X2 - CI2, malonato 

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The chemistry of titanium has been reviewed in COMC (1982) and COMC (1995)40 41 as well as in Comprehensive Coordination Chemistry II. 2 Since then, several contributions have covered the coordination chemistry of cyclopenta-dienyltitanium carboxylates and related complexes,43 new titanium imido chemistry,44 the use of titanium(iv) chloride45 and isopropoxide46 in stereoselective synthesis, the preparation and synthetic applications of l, -dicarba-nionic titanium intermediates47 and organotitanium complexes,48 49 and titanium-catalyzed enantioselective... 

The coordination chemistry of Cp titanium carboxylates and related complexes has been reviewed. The synthetic methods, structural characteristics, coordination modes, and reactivities are covered.1570... 

Carboxylate and Related Complexes. The FTIR spectrum of M(Nap)3 (phen), where M = Y, La, Eu, Tb or Dy HNap = a-naphthoic acid, includes bands from bidentate carboxylates.348 IR and Raman data for [Ln(2,6-dhb)5(H20)2]2, where Ln = Sm, Tb Hdhb = 2,6-dihydroxybenzoic acid, also reveal vC02 bands from bidentate carboxylates.349 vC=0 bands for homo-binuclear Ln3+ complexes of (65) linked by p-xylyl groups are seen in the range 1580-1600 cm-1, compared to 1690 cm-1 for the free ligand (Ln = Eu, Tb, Yb).350... 

The coordination and organometallic chemistry of zirconium and hafnium are surveyed for the year 1991.107,108 There is useful material in a review of homogeneous Group 4 metallocene Ziegler-Natta catalysts, a review of the coordination chemistry of cyclopentadienyl titanium carboxylate and related complexes O and a review of bis(cycIopentadienyl)zirconium(IV) or hafnium(IV) complexes with Si-, Ge-, Sn-, N-, P-, As-, Sb-, 0-, S-, Se-, Te- or transition metal-centred anionic ligands. Cationic zirconocene or hafiiocene complexes serve as Lewis acids with unique reactivities, they are active for C-F bond activation, coordinative activation of ether linkages, carbonyl activation and C-O bond cleavage. New synthetic methods based on the... 

The compounds Ln(C5H5)2Cl also have been made only with the lanthanides above samarium (772). These compounds are stable in the absence of air and moisture, sublime near 200 °C, are insoluble in non-polar solvents, and exhibit room temperature magnetic moments near the free ion values (772, 113). The chloride ion may be replaced by a variety of anions including methoxide, phenoxide, amide and carboxylate. Some of these derivatives are considerably more air-stable than the chloride — the phenoxide is reported to be stable for days in dry air. Despite their apparent stability, little is known about the physical properties of these materials. The methyl-substituted cyclopentadiene complexes are much more soluble in non-polar solvents than the unsubstituted species. Ebulliometric measurements on the bis(methylcyclopentadienyl)lanthanide(III) chlorides indicated the complexes are dimeric in non-coordinating solvents (772). A structmre analysis of the ytterbium member of this series has been completed (714). The crystal and molecular parameters of this and related complexes are compared in Table 5. 

DINUCLEAR COMPLEXES CONTAINING CARBOXYLATE AND RELATED BRIDGING LIGANDS... 

Other related complexes (where the acetate can be replaced by another carboxylate) and new complexes were synthesized and found to have similar behavior they are now called single-molecule magnets , SMMs [4-8]. 

Complexes with water, alcohols artd related ligands Complexes with ketones, aldehydes, ethers and related ligands Complexes with fi-diketones, tropolonates, catecholates, quinones and related ligands Complexes with oxoanions as ligands Complexes with carboxylates and related ligands... 

Complexes with carboxylates and related ligands Complexes with inorganic oxo anions Basic salts of mercury (II)... 

Molecular Oxygen, Peroxo, Aquo and Related Complexes - The complex [ V0(02)(I/-H2tart) 2(p-H20)], where H art = tartaric acid, has vOO at 933 cm together with characteristic bands of unidentate carboxylates. The IR and Raman spectra of the peroxoniobate, Rb3Nb(02)4 contain vOO bands at 838 cm (ai) and 814 cm (e) (using D2d molecular symmetry). ... 

Metal-Cyano and Nitrile Complexes Ammine, Amido, Urea and Related Complexes Metal Carbonyl Compounds Metal-Acetylacetonato Compounds, Carboxylate Complexes and Complexes Involving the Carbonyl Group... 

Nylon resins are made by numerous methods (53) ranging from ester amidation (54) to the Schotten-Baumann synthesis (55). The most commonly used method for making nylon-6,6 and related resins is the heat-induced condensation of monomeric salt complexes (56). In this process, stoichiometric amounts of diacid and diamine react in water to form salts. Water is removed and further heating converts the carboxylate functions to amide linkages. Chain lengths are controlled by small amounts of monofunctional reagents. The molten finished nylon resin can be dkectly extmded to pellets. 

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