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Cu(C4HI6N4)][Ni(CN)4], Mr = 346'5, triclinic, Pi, a=6.460(9), b= 7.230(10), c= 7.864 (15)A, a = 106.81 (13), /3 =91"51 (14), y= 106.94 (12) °, V= 333"9 (9) A 3, Z= 1, O m = 1"71 (1), Dx=1"723Mgm -3, A(MoKa)=0-71069A, /x= Abstract. [V¢(C12H10N6)(CO)4], Mr---534.14, monoclinic, P2Jc, a=15.327(2), b=13.993(2), c= * To whom correspondence should be addressed. 0108-2701/91 / 112448-04503.00 18.526 (2)/~, fl = 114.00 (1) °, V = 3629.7 (9)/~3, Z= 8, Dx = 1.95 Mg m -3, ,~(Mo Ka) = 0.71073/~, /z = 6.535 mm-1, F(000) = 2032, T = 298 K, R (wR) = 0.023 (0.030) for 5538 unique observed reflections [I

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Homopolymerization and copolymerization of 2-vinylpyridine (2VP) with styrene (S) at 125°C in the presence of 2,2,6,6-tetramethyl piperidin-1-yloxyl (TEMPO) radicals have been studied. The homopolymerization was carried out with 2,2Ј-azobis-(isobutyronitrile) (AIBN) as a thermal initiator or without AIBN in the initial reaction mixture. In the copolymerization initiated with AIBN, the molar fraction of 2VP in the feed, F 2VP , varied in the range of 0.1-0.9; F 2VP ϭ 0.65 was found to be the azeotropic composition. The linear semilogarithmic time-conversion plots demonstrated a pseudoliving nature of the polymerizations under study. The molecular weight-conversion dependences indicated the participation of side reactions, diminishing the number of TEMPO-terminated polymer chains. The synthesized homopolymers and copolymers were characterized using size-exclusion chromatography (SEC), nitrogen analysis, and NMR spectroscopy.

Autopolymerization of styrene-N-butylmaleimide mixtures at 125 or 140°C in the presence of a stable nitroxyl radical [2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO)] was found to proceed in a pseudoliving manner. Unimolecular initiators, which were originated by trapping self-generated radical species with TEMPO, took part in the process. Under the studied experimental conditions, the TEMPO-controlled autopolymerization with a varying comonomer ratio provided virtually alternating copolymers of narrow molecular weight distributions. The molecular weights of the copolymers increased with conversions. The obtained styrene-N-butylmaleimide copolymers containing TEMPO end groups were used to initiate the polymerization of styrene. The polymerization yielded poly(styrene-co-N-butylmaleimide)-polystyrene block copolymers with various polystyrene chain lengths and narrow molecular weight distributions. The compositions, molecular weights, and molecular weight distributions of the synthesized block copolymers and the initial poly(styrene-co-N-butylmaleimide) precursors were evaluated using nitrogen analysis, gel permeation chromatography, and 1 H-and 13 C-NMR spectroscopy.

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