Ligand field strength

Is there a correlation between the ligand field strength of the halide ions F, Cl, Br, and 1 and the electronegativity of the halogen If so, can this correlation be explained by ligand field theory Justify your answer. 

Fig. 7.31 Partial ligand-field strength for the ligand L in correlation with the isomer shift 5 (relative to Ru metal at 4.2 K) of the nitrosylruthenium (II) compounds [RuL5(NO)]" (L = Br, Cr, NCS, NH3, CN ) (from [124])...

These results obtained in applied field clearly prove that the ST in the dinuclear compounds under study proceeds via [HS-HS] O [HS-LS] O [LS-LS]. Simultaneous ST in both iron centers of the [HS-HS] pairs, leading directly to [LS-LS] pairs, apparently can be excluded, at least in the systems discussed above. This is surprising in view of the fact that these dinuclear complexes are centrosymmetric, that is, the two metal centers have identical surroundings and therefore, experience the same ligand field strength and consequently, thermal ST is expected to set in simultaneously in both centers. In other dinuclear iron(II) complexes, however, thermally induced direct ST from [HS-HS] to [LS-LS] pairs does occur and, indeed, has been observed by Mossbauer measurements [30, 31]. 

The constraints imposed by the additional trimethylene strap in the macrocyclic diamide complex of (623) causes the Ni11 ion to be pushed out of the N4 plane and results in a lower ligand field strength than in the Ni11 complex of the corresponding monocyclic dioxocyclam ligand.1 71... 

The spectrum of the octahedral Ni11 complex (580) with a hexaaza macrobicyclic ligand is similar to that of [Ni(en)3]2+, but the ligand field strength of the complex is increased slightly by the capping of the [Ni(en)3]2+ moiety with two tris(methylene)amino groups.1461... 

It is well-established that the molecular and electronic structures of metal complexes of azamacrocycles are greatly affected upon N-alkylation (197). This is mainly due to two factors (a) the decrease of the ligand field strength and (b) the increase in the steric requirements upon going from a secondary to a tertiary amine donor function (251). To examine whether the properties of the dinuclear amine-thiophenolate complexes are affected by the N-alkyl substituents, analogous complexes of the... 

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