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d‐Block transition‐metal‐containing polymer blends which form coordination complexes are described in this treatise. The model compounds are zinc acetate dihydrate, copper acetate dihydrate, nickel acetate tetrahydrate, cobalt chloride hexahydrate, palladium chloride bis (acetonitrile), and the dimer of dichlorotricarbonylruthenium (II). Two classes of ligands are of interest. Poly (4‐vinylpyridine), P4VP, and copolymers that contain 4‐vinylpyridine repeat units form complexes with zinc, copper, nickel, cobalt, and ruthenium salts. Atactic 1,2‐polybutadiene contains olefinic sidegroups that displace weakly bound acetonitrile ligands and coordinate to palladium chloride. Thermal analysis via differential scanning calorimetry suggests that the glass transition temperature of the polymeric ligand is enhanced by these low‐molecular‐weight transition‐metal salts in binary and ternary blends. In some cases, d‐block salts function as transition‐metal compatibilizers for copolymers that would otherwise be immiscible. The isothermal ternary phase diagram for polybutadiene with palladium chloride highlights regions of gelation, precipitation, and transparent solutions during blend preparation in tetrahydrofuran. Fourier transform infrared spectroscopy provides molecular‐level data that support the concept of polymeric coordination complexes. High‐resolution carbon‐13 solid‐state NMR spectroscopy identifies (1) near‐neighbor interactions between polymeric pyridine ligands and the ruthenium salt, and (2) a considerable reduction in the molecular mobility of the polybutadiene chain backbone when it forms a coordination complex with palladium chloride. The elastic modulus of polybutadiene increases by three orders of magnitude when the palladium salt concentration is 4 mol % in a solid‐state glassy film. A thermodynamic interpretation of ligand field stabilization energies appropriate to tetrahedral cobalt and octahedral nickel complexes is employed to estimate the synergistic enhancement of the glass transition temperature, particularly when coordination crosslinks are present. ©1995 John Wiley & Sons, Inc.

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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.