DendriMacs. Well-defined dendritically branched polymers synthesized by an iterative convergent strategy involving the coupling reaction of AB₂ macromonomers

We describe here the first example of an iterative convergent strategy for the synthesis of dendritically branched polymers involving condensation coupling reactions of AB2 macromonomers. The macromonomers were synthesized by living anionic polymerization, initiated with 3-tert-butyldimethylsiloxy-1-propyllithium and end capped with 1,1-bis(4-tert-butyldimethylsiloxyphenyl) ethylene. Following a deprotection reaction, the macromonomer, functionalized with two phenol groups and one primary alcohol group, can be built up into a dendritic structure by a series of Williamson coupling reactions and subsequent end group modification reactions. Since the dendritic structures are built up from macromonomers we have coined the term "DendriMac" to describe these branched polymers. In this paper, we will discuss the synthesis of the macromonomer, the iterative reaction sequence and merits of a convergent strategy. Some preliminary characterization data will also be reported

HyperMacs. Long chain branched analogues of hyperbranched polymers prepared by the polycondensation of AB(2) macromonomers.

We describe here a new strategy for the synthesis of polymers with highly branched architectures. The strategy involves the synthesis by anionic polymerization of well-defined AB2 polystyrene macromonomers with molecular weights from 3,600 to 94,000 gmol−1, which are then converted via a one-pot polycondensation reaction into high molecular weight, long-chain (hyper)branched architectures. Since the Hyperbranched structures are built up from condensation Macromonomers we have coined the term ‘HyperMac’ to describe these branched polymers. In this paper we report the synthesis of the HyperMacs, the optimal conditions for the polycondensation reaction and some preliminary characterization studies

HyperMacs: Highly branched polymers prepared by the polycondensation of AB₂ macromonomers, synthesis and characterization

We describe here a new strategy for the synthesis of polymers with highly branched architectures. The strategy involves the synthesis by anionic polymerization of well-defined AB(2) polystyrene (condensation) macromonomers with molecular weights from 3500 to 38 000 g mol(-1), which are then converted via a one-pot polycondensation reaction into high-molecular-weight, long-chain (hyper)branched architectures. Because the hyperbranched structures are built up from condensation macromonomers, we have coined the term "HyperMac" to describe these branched polymers. In this paper, we report the synthesis of the macromonomers, the optimal conditions for the polycondensation reaction, and some preliminary characterization studies

Nickel dithiolenes containing pendant thiophene units: precursors to dithiolene-polythiophene hybrid materials

The synthesis, electrochemical and spectroscopic properties of the new thiophene-substituted metal dithiolene complexes [Ni(b-3ted)2] ( 3) and [NBu4][Ni(b-3ted)2] ([NBu4][ 3]) are described [b-3ted = bis(3-thienyl)-1,2-ethylenedithiolene] and compared with new studies of the known compounds [Ni(b-2ted)2] ( 2) and [NBu4][Ni(b-2ted)2] ([NBu4][ 2]). X-Ray structures were determined for the neutral complexes 2 and 3 and both showed planar nickel dithiolene units with thiophene groups twisted out of the molecular plane, precluding close molecular -stacking. Electrochemical investigations revealed two redox processes corresponding to interconversion between neutral, monoanionic and dianionic species for 3, analogous to 2. Oxidation of 0.1 mM [ 3]– in CH3CN was shown to give a green molecular film of 3 which, in contrast to as-prepared crystals of 3, showed significant conductivity. Electrochemical polymerisation of 3 carried out at different concentrations resulted in films; electrochemical, SNIFTIRS and UV-Vis results were consistent with incorporation of the intact metal dithiolene complex in these films. In contrast, electrochemical polymerisation of 2 gave a film charateristic of a polymerised thiophene but with no evidence of incorporation of the intact metal dithiolene complex. Copolymerisation of 3 with thiophene gave a gold-coloured electropolymerised film of significant conductivity that, upon dissolution in CH2Cl2, showed the characteristic low energy absorption of the Ni-dithiolene complex, confirming its incorporation. This copolymerisation approach offers a versatile route to the synthesis of metal dithiolene–polythiophene hybrid films

Nickel dithiolenes containing pendant thiophene units: precursors to dithiolene-polythiophene hybrid materials

The synthesis, electrochemical and spectroscopic properties of the new thiophene-substituted metal dithiolene complexes [Ni(b-3ted)2] ( 3) and [NBu4][Ni(b-3ted)2] ([NBu4][ 3]) are described [b-3ted = bis(3-thienyl)-1,2-ethylenedithiolene] and compared with new studies of the known compounds [Ni(b-2ted)2] ( 2) and [NBu4][Ni(b-2ted)2] ([NBu4][ 2]). X-Ray structures were determined for the neutral complexes 2 and 3 and both showed planar nickel dithiolene units with thiophene groups twisted out of the molecular plane, precluding close molecular -stacking. Electrochemical investigations revealed two redox processes corresponding to interconversion between neutral, monoanionic and dianionic species for 3, analogous to 2. Oxidation of 0.1 mM [ 3]– in CH3CN was shown to give a green molecular film of 3 which, in contrast to as-prepared crystals of 3, showed significant conductivity. Electrochemical polymerisation of 3 carried out at different concentrations resulted in films; electrochemical, SNIFTIRS and UV-Vis results were consistent with incorporation of the intact metal dithiolene complex in these films. In contrast, electrochemical polymerisation of 2 gave a film charateristic of a polymerised thiophene but with no evidence of incorporation of the intact metal dithiolene complex. Copolymerisation of 3 with thiophene gave a gold-coloured electropolymerised film of significant conductivity that, upon dissolution in CH2Cl2, showed the characteristic low energy absorption of the Ni-dithiolene complex, confirming its incorporation. This copolymerisation approach offers a versatile route to the synthesis of metal dithiolene–polythiophene hybrid films