Heteroligand Complexes

The concept of the formation of heteroligand complexes in the melts explains the appearance of peaks in the range of 5 — 10 % (mass) of K2TaF7 [324] on the isotherms of the specific conductivity of molten mixtures KC1 -KF - K2TaF7 (Fig. 67). 

Analysis of the physicochemical properties of fluoride and oxyfluoride melts reveals that the complex ions are characterized by coordination numbers that do not exceed seven. Fluoride melts consist of the complex ions MeF72 and MeFe. Molten chloride-fluoride systems initiate the formation of heteroligand complexes of the form MeFgCl2 . Oxyfluoride and oxyfluoride-chloride melts can contain oxyfluoride complexes MeOF63 at relatively low concentrations. The behavior of the more concentrated melts can be attributed to the formation of oxyfluorometalate polyanions. 

Applications of heteroligand complexes in the analytical chemistry of niobium and tantalum. S. V. Elinson, Russ. Chem. Rev. (Engl. Transl.), 1975,44, 707-717 (131). 

Heterogenous reactions, Sh/Nu ratio, 27 64 Heteroligand complex, 32 260-262 Heteropolyacids defined, 41 117 heteroatoms, 41 118, 120, 121 Prins reaction, 41 156 supported, 41 149-150 Heteropolyanions, 41 113, 117, 119-121 Heteropoly blues, 41 191 Heteropoly compounds absorption, 41 179-180, 190-191 acid-catalyzed reactions heterogeneous, 41 161-178 liquid phase, 41 150-161 acidic properties in solid state, 41 141-150 in solution, 41 139—14] catalysis, 41 114, 116-117, 190-191 as catalyst, 41 113-116, 117, 223-232... 

Fig. 28. Stereochemical models of (A) intermediate complex and (B) heteroligand complex.

V Chemical Shifts of Selected Aqueous Oxobisperoxovanadate Heteroligand Complexes of VL2X Stoichiometry... 

Equilibrium Constants for Selected Monodentate Heteroligand Complexes of Bisperoxovanadate9... 

The probable dioxygenase-like mechanism of the iron catalyst transformation in the presence H20 is offered. The discovered fact of increase in parameters Speh , C (and S- C) at catalysts of the ethylbenzene oxidation by Fe(III)(acac)3 + CTAB + H2O( 10 3 mol/1) system may be result of the increase in stationary concentration of active selective heteroligand complexes of probable structure Fe(II)x(acac)y(OAc)z(CTAB)n(H20)m, intermediate products of transformation of complexes (Fe(II)(acac)2)x,(CTAB)y (H20)n in the course of the ethylbenzene oxidation. 

Klabunovskii et al. suggested that hydrogenation of EAA or acetylacetone would be perfomed through reaction of a heteroligand complex... 

Table 4.17. Relationship between the conformation of the dicarbonyl-compounds in their heteroligand complexes with amino acids and the configuration of the hydrogenation products.

Pavlov, V.A., Piloyan, S.R., and Klabunovskii, E.l. (1980) Studies of optically active heteroligand chelate complexes. Comm. 7. Heteroligand complexes as models of intermediate complexes in enantioselective hydrogenation catalysis, Izv. Acad. Nauk. SSSR, Ser. khim. 545 - 551. 

A ) (Scheme 1-3) [59-61], Transformation of complexes Ni(acac)2 L (L = HMPA, DMF, MP, MSt)) leads to formation of homo bi-(L = HMPA, DMF, MP) or hetero three nuclear (L = MSt, M=Na, Li, K) heteroligand complexes A Ni2(OAc)3(acac)L (Scheme 1) [10], The structure of the complex A with =MP is proved kinetically and by various physical-chemical methods of analysis (mass-spectrometry, electron and IR-spec-troscopy, element analysis). 

Thus, we established the interesting fact - the catalytic effect of small concentrations of quaternary ammonium salts, [R NBr] = 0.5-10 mol/l, which in 10 times less than [Fe(III)(acac)3]. It is known that salts QX can form complexes with metal compounds of variable composition which depends on the nature of solvent [93]. The formation of poly nuclear heteroligand complexes (Fe(II)(acac)2) -(R NBr)y (and Fe(II) (acac)y(OAc) (R NBr) also) seems to be probable. 

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