Metalloinitiation routes to biocompatible poly(lactic acid) and poly(acrylic acid) stars with luminescent ruthenium tris(bipyridine) cores.
Poly(lactic acid) (PLA) and poly(acrylic acid) (PAA) biomaterials with luminescent ruthenium tris(bipyridine) centers couple drug delivery and imaging functions. Hydrophobic [Ru(bpyPLA2)3](PF6)2 (1) was generated from [Ru[bpy(CH2OH)2]3](PF6)2 in bulk monomer using 4-(dimethylamino)pyridine as the catalyst. The bromoesters, [Ru[bpy(CH2OR)2]3](PF6)2, [Ru[bpy(C13H27)2][bpy(CH2OR]2](PF6)2 (4), and [Ru[bpy(PLAOR)2]3]2+ (9) (R=COCBr(CH3)2), served as initiators for tert-butyl acrylate (tBA) polymerization. Conversion of PtBA to PAA via hydrolysis affords water soluble materials, [Ru(bpyPAA2)3]2+ (7) and [Ru[bpy(C13H27)2](bpyPAA2)2]2+ (8) and the amphiphilic star polymer [Ru[bpy(PLA-PAA)2]3)](PF6)2 (11), which is soluble in a H2O/CH3CN (1:1) mixture. Luminescence excitation and emission spectra of the Ru polymers were in agreement with the parent [Ru(bpy)3]2+ chromophore (lambdaex=468, lambdaem=621 nm). Lifetimes of tau approximately 700 ns in both air and nitrogen atmospheres are typical for most materials; however, the amphiphilic star block copolymer 11 is quenched by oxygen to some degree. Thermal analysis shows the expected glass transitions for the polymeric ruthenium complex materials.
Department of Chemistry, University of Virginia, McCormick Road, PO Box 400319, Charlottesville, Virginia 22904-4319, USA.
Robert M
RM
Johnson
Cassandra L
CL
Fraser
D000180:Acrylic Resins / Q000032:analysis / Q000737:chemistry*; D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry*; D004355:Drug Stability; D019344:Lactic Acid / Q000032:analysis / Q000737:chemistry*; D008163:Luminescent Measurements; D009942:Organometallic Compounds / Q000032:analysis / Q000737:chemistry*; D011091:Polyesters; D011108:Polymers / Q000032:analysis / Q000737:chemistry*
D000180:Acrylic Resins; D001672:Biocompatible Materials; D009942:Organometallic Compounds; D011091:Polyesters; D011108:Polymers; C474397:ruthenium tris(2,2'-bpyridyl)(ClO4)2(H2O); D019344:Lactic Acid; C033616:poly(lactide); C006903:carbopol 940