Category: amides-buliding-blocksOn November 3, 2014 ,《Large Thermal Hysteresis for Iron(II) Spin Crossover Complexes with N-(Pyrid-4-yl)isonicotinamide》 appeared in Inorganic Chemistry. The author of the article were Lochenie, Charles; Bauer, Wolfgang; Railliet, Antoine P.; Schlamp, Stephan; Garcia, Yann; Weber, Birgit. The article conveys some information:
Fe(II) 1-dimensional coordination polymers [FeL1(pina)]·xsolvent with L1 being a tetradentate N2O22- coordinating Schiff-base-like ligand [([3,3′]-[1,2-phenylenebis(iminomethylidyne)]bis(2,4-pentanedionato)(2-)-N,N’,O2,O2′], and pina being a bridging axial ligand N-(pyrid-4-yl)isonicotinamide, are discussed. The x-ray crystal structure of [FeL1(pina)]·2MeOH was solved for the low-spin state. The compound crystallizes in the monoclinic space group P21/c, and the anal. of the crystal packing reveals the formation of a H bond network where addnl. MeOH mols. are included. Different magnetic properties are observed for the seven samples analyzed, depending on the nature of the included solvent mols. The widest hysteresis loop is observed for a fine crystalline sample [FeL1(pina)]·xH2O/MeOH. The 88 K wide thermal hysteresis loop (T1/2↑ = 328 K and T1/2↓ = 240 K) is centered around room temperature and can be repeated without of a loss of the spin transition properties. For the single crystals of [FeL1(pina)]·2MeOH, a 51 K wide hysteresis loop is observed (T1/2↑ = 296 K and T1/2↓ = 245 K) that is also stable for several cycles. For a powder sample of [FeL1(pina)]·0.5H2O·0.5MeOH a cooperative spin transition with a 46 K wide hysteresis loop around room temperature is observed (T1/2↑ = 321 K and T1/2↓ = 275 K). This compound was further studied using Mossbauer spectroscopy and DSC. Both methods reveal that, in the cooling mode, the spin transition is accompanied by a phase transition while in the heating mode a loss of the included MeOH is observed that leads to a loss of the spin transition properties. The pina ligand was used successfully in a crystal-engineering-like approach to generate 1-dimensional coordination polymers and improve their spin crossover properties. In addition to this study using N-(Pyridin-4-yl)isonicotinamide, there are many other studies that have used N-(Pyridin-4-yl)isonicotinamide(cas: 64479-78-3Category: amides-buliding-blocks) was used in this study.
N-(Pyridin-4-yl)isonicotinamide(cas: 64479-78-3) belongs to amides. Because of the greater electronegativity of oxygen, the carbonyl (C=O) is a stronger dipole than the N–C dipole. The presence of a C=O dipole and, to a lesser extent a N–C dipole, allows amides to act as H-bond acceptors.Category: amides-buliding-blocks In primary and secondary amides, the presence of N–H dipoles allows amides to function as H-bond donors as well.
Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics