Solid state complexes of poly(L‐lysine) with metal chlorides from the 1st row of the d‐block

Abstract

Solid state characterization of poly(L‐lysine)hydrobromide was obtained via differential scanning calorimetry, thermogravimetric analysis, optical microscopy and infrared spectroscopy. The glass transition temperature of poly(L‐lysine)hydrobromide is 178°C. This thermal transition has not been reported previously. Poly(L‐lysine)'s Tg decreases when complexes are produced with the following divalent transition metal chlorides; cobalt chloride hexahydrate, nickel chloride hexahydrate, copper chloride dihydrate and anhydrous zinc chloride. At 10 mol% salt, nickel, chloride decreases Tg by 45°C, and the general trend is Ni2+Co2+Zn2+Cu2+. The depression of poly(L‐lysine)'s Tg correlates well with ligand field stabilization energies for pseudo‐octahedral and pseudo‐tetrahedral dn complexes (n = 7, 8, 10) from the 1st row of the d‐block. However, d9 copper(II) complexes cannot be included in this empirical correlation. Infrared spectroscopic evidence suggests that Co2+, Ni2+ and Zn2+ coordinate to the carbonyl oxygen in the main chain of the polymer. When transition metal ions coordinate to CO, the network of hydrogen bonded amide groups is disrupted, which lowers the glass transition. The amide I region of the infrared spectrum reveals a hydrogen bonded CO stretch @ 1655 cm−1 that is characteristic of poly(α‐amino acid) random coil conformations, and a metal‐ligand coordinated CO stretch @ 1625 cm−1 in complexes with divalent cobalt, nickel and zinc. The amide II region of the infrared spectrum near 1550 cm−1 is also sensitive to the formation of coordination complexes with these d‐block metal chlorides.

Transition metal compatibilization of poly(vinylamine) and poly(ethylene imine)

“…Previous research in our laboratory 8,9,13,[17][18][19][20][21][22][23] has focused on divalent zinc, copper, nickel, cobalt, ruthenium and palladium complexes. Pyridine ligands in poly(4-vinylpyridine) and 4-vinylpyridine copolymers coordinate to zinc, copper, nickel, cobalt and ruthenium.…”

“…[15][16][17][18] Usually, some of these coordination sites in the first shell are occupied by anionic ligands that are required for neutral complexes, waters of hydration, carbon monoxide, or acetonitrile.…”

Controls exerted by the Aib residue: Helix formation and helix reversal This article is a US Government work and, as such, is in the public domain in the United States of America.

“…Ethylene ionomers are copolymers consisting of methylene sequences as nonpolar segments and a small amount of methacrylic acid or acrylic acid residues as ionic units 1–24. It is well known that the ionic groups are partially or fully neutralized by metal ions such as Zn 2+ , Na + , Ca 2+ , Cu 2+ , or Mn 2+ 1–26.…”

“…Ethylene ionomers are copolymers consisting of methylene sequences as nonpolar segments and a small amount of methacrylic acid or acrylic acid residues as ionic units 1–24. It is well known that the ionic groups are partially or fully neutralized by metal ions such as Zn 2+ , Na + , Ca 2+ , Cu 2+ , or Mn 2+ 1–26. Because information about the structure and dynamics of ethylene ionomers is indispensable to an understanding of their mechanical, thermal, and other important physical properties, many investigations have been performed with differential scanning calorimetry (DSC),2, 3, 8, 10, 11, 13, 14, 17, 18 X‐ray diffractrometry,2–4, 13, 15, 18, 20, 23, 25, 26 Raman spectroscopy,5, 19 infrared (IR) spectroscopy,7, 8, 13, 19, 22, 24 electron spin resonance spectroscopy,12 dynamic mechanical analysis,13, 14, 17 and dielectric relaxation measurements 13, 16…”

Effect of metal salts in the optical properties of polydiacetylenes

“…Ionic groups such as carboxylates are commonly implemented in these polymers [15,16,[18][19][20]. Neutral groups like amines [21][22][23][24][25] and amides [26] are also utilized. For these reasons, films of aliphatic PDA-containing polyesters with metal salts of Zn, Eu and Gd were prepared, and the influence of these metal salts in the optical properties of the developed PDA films is extensively discussed within this work.…”