Amides as ligands. VII. Complexes of N-methyl-.gamma.-butyrolactam with nontransition metals

Coordination of N-methylpyrrolidone to iron(II)

“…The presence of NMP in the crystals is also confirmed using FTIR spectroscopy, which shows a characteristic amide band at 1650 cm À1 [13]. This C@O stretching frequency is consistent with the values observed for NMP coordinated to main-group metals such as Ca(II), Mg(II), and Zn(II) [14]. The infrared spectrum also shows a weak C-H band at 2930 cm À1 .…”

Interplay of Internal Structure and Interfaces on the Emitting Properties of Hybrid ZnO Hierarchical Particles

“…Thus, FTIR spectroscopy suggests that the coordination of PVP onto the ZnO surface can occur either through the oxygen or through the nitrogen atom of the NCO bond. The magnitude of the shifts observed by infrared spectroscopy can be directly correlated with the relative strength of the interaction . The red-shift is larger than the blue-shift, and therefore the coordination through the oxygen atom seems to be favored, in agreement with the above steric considerations.…”

“…The coordination mode (V) in Figure f implies an appreciable steric hindrance, and consequently, in the liquid phase and on ionic metal centers, the coordination of lactam groups has been found to occur almost exclusively through the oxygen atom, especially for a coordination number equal to six. ,− The situation might be completely different when the coordination of PVP occurs on solid surfaces, where movements of the atoms are severely restricted if not prevented. Under these conditions, different conformations are possible for the polymer, according to the surface coverage …”

Preparation of PMDA/ODA polyimide membrane for use as substrate in a thermally stable composite reverse osmosis membrane

“…An intersection at 6% can be clearly observed, at which point the molar ratio of Zn 2+ to 2COOH can be calculated to be 1.2, close to equality. These results may be explained by the interaction between Zn 2+ and both the polymer PAA [23] and the solvent NMP [26]. Due to the strong coordination interaction between Zn 2+ ion and carboxylic groups [27], initially each Zn 2+ ion preferably binds to two PAA carboxylic groups in an intermolecular manner forming an ionic cross-linking network, as shown in Fig.…”