Electronic coupling in cyano-bridged ruthenium polypyridine complexes and role of electronic effects on cyanide stretching frequencies

[NiII(tn)2]5[FeIII(CN)6]2[FeII(CN)6]·10H2O: A 3-dimensional dimetallic polymer exhibiting ferromagnetic interaction

“…The IR spectrum of [Ni II (tn) 2 ] 5 [Fe III (CN) 6 ] 2 [Fe II (CN) 6 ] AE 10H 2 O shows two bands at 2108 and 2057 cm À1 , which is assigned to the intermetallic Fe III -C"N-Ni II and Fe II -C"N-Ni II bonds, m[C"N(b)]. The shift of m(C"N) to lower wavenumber compared with that of K 3 [Fe(CN) 6 ] (m CN 2131 cm À1 ) is consistent with the formation of C"N bridges as revealed by the X-ray analysis [14].The ORTEP view of [Ni II (tn) 2 ] 5 [Fe III (CN) 6 ] 2 [Fe II (C-N) 6 ] AE 10H 2 O is shown in Fig. 1 [15].…”

Intervalence Charge Transfer (IVCT) in Ruthenium Dinuclear and Trinuclear Assemblies Containing the Bridging Ligand HAT {1,4,5,8,9,12‐hexaazatriphenylene}

“…The apparent splitting of the IVCT transition into two components in the trinuclear case was attributed to non-negligible superexchange-assisted through-bond coupling between the remote metal centres, and the result was rationalised by the construction of adiabatic energy surfaces for the trinuclear system. [68][69][70][71] For the HAT-bridged systems in the present study, the three metal centres share the same bridging ligand, and are equivalently disposed from one another, such that a remote superexchange mechanism cannot be invoked.…”

“…[68][69][70][71] The NIR region of the mixed-valence species exhibited a broad band (assigned as an IVCT transition) in the region 4500-12 000 cm À1 which appeared to comprise of two underlying components of approximately equal intensity. By comparison, the analogous dinuclear complex [NC-Ru II (bpy) 2 -CN-Ru III (bpy) 2 -CN] 2 + revealed a single absorption band at 5700 cm…”

Vitamin B12Model Complexes: Synthesis and Characterization of Thiocyanato Cobaloximes and Thiocyanato Bridged Dicobaloximes of O-donor Ligands: DNA Binding and Antimicrobial Activity

“…This shift to higher frequency upon bridging is explained on the basis of force field arguments. 26 This type of increase in the C=N stretching frequency upon forming complexes containing bridging cyanide ligands from terminal thiocyanide complexes was documented by Wilmarth et al 27 Since, then it has found to be a general phenomenon. This behavior is taken as a justification for the formulation of these dimers as thiocyano bridged dicobaloximes.…”