Sudhir Achar

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


This thesis describes new routes to organometallic polymers and dendrimers employing an oxidative addition method. The new complexes {dollar}\lbrack\rm PtMe\sb2(NN)\rbrack{dollar} 1, (1b: (NN) = 4,4{dollar}\sp\prime{dollar}-di-tert-butyl-2,2{dollar}\sp\prime{dollar}-bipyridine; 1c: (NN) = 4,4{dollar}\sp\prime{dollar}-dimethyl-2,2{dollar}\sp\prime{dollar}-bipyridine; 1d: (NN) = 4-vinyl-4{dollar}\sp\prime{dollar}-methyl-2,2{dollar}\sp\prime{dollar}-bipyridine) were shown to be useful precursors to polymers. {dollar}\{lcub}{dollar}Note 1a: (NN)= 2,2{dollar}\sp\prime{dollar}-bipyridine{dollar}\{rcub}{dollar}.;The oxidative addition of organic halides (R-X) to 1 gave {dollar}\lbrack\rm PtXMe\sb2R(NN)\rbrack{dollar} {dollar}\rm\{lcub} (NN)\sb{lcub}1a{rcub}{dollar}: R-X = methyl 2-(bromomethyl)acrylate; 2-(bromomethyl)acrylic acid; 2-bromoethyl methacrylate; methyl bromoacetate; ethyl bromoacetate; bromoacetic acid; bromoacetonitrile and bromoacetamide. {dollar}\rm (NN)\sb{lcub}1b{rcub}{dollar}: (R-X) = 2-bromoethyl methacrylate and vinyl bromoacetate. {dollar}\rm (NN)\sb{lcub}1d{rcub}{dollar}: vinyl bromoacetate; 2-bromoethyl methacrylate; acryloyl chloride and vinylbenzyl chloride{dollar}\{rcub}{dollar}.;The free radical polymerization of the monomer 2-bromoethyl methacrylate gives the organic polymer which oxidatively adds to 1a to give a partially platinated polymer, or, alternatively, oxidative addition of the organic monomer to 1a gives the organoplatinum(IV) monomer which undergoes free radical polymerization to yield fully metallated polymer. The effect of different metal loadings on the polymer characteristics are reported. The methodology is extended to synthesize organoplatinum polymers using vinylbenzyl chloride and acryloyl chloride.;The diester {dollar}\rm BrCH\sb2CO\sb2CH\sb2CH\sb2O\sb2CCH\sb2Br{dollar} reacts with 1b to give the bridged dimer {dollar}\rm \lbrack\{lcub} PtBrMe\sb2(NN)\{rcub}\sb2(\mu{dollar}-{dollar}\rm CH\sb2CO\sb2CH\sb2CH\sb2O\sb2CCH\sb 2)\rbrack.{dollar} X-ray single crystal structure determinations of this dimer and {dollar}\rm\lbrack PtBrMe\sb2(CH\sb2CO\sb2CH\sb3)(bipy) \rbrack{dollar} are reported. The polymerization of {dollar}\rm\lbrack PtBrMe\sb2(CH\sb2CO\sb2CH{dollar}={dollar}\rm CH\sb2)(bu\sb2bipy)\rbrack{dollar} gives the polymer {dollar}\rm\lbrack\{lcub} PtBrMe\sb2(bu\sb2bipy)(CH\sb2CO\sb2)\{rcub}{dollar} CH-{dollar}\rm CH\sb2{dollar}-) {dollar}\sb{lcub}n{rcub}.{dollar};A novel approach to linear organoplatinum oligomers was developed. The oxidative addition of 4-bromomethyl-{dollar}4\sp\prime{dollar}-methyl-2,{dollar}2\sp\prime{dollar}-bipyridine to 1b yields a platinum(IV) complex with a free diimine functionality, which was used to complex to a new {dollar}\rm Me\sb2Pt\sp{lcub}II{rcub}{dollar} centre. Repetition of these reactions in sequence yielded the linear oligomers. Slight modification of the procedure gave the first example of a star shaped {dollar}\rm Pt\sb{lcub}12{rcub}{dollar} complex.;A new strategy was developed to synthesize the first examples of organotransition metal dendrimers. The oxidative addition of 4,{dollar}4\sp\prime{dollar}-bis(bromomethyl)-2,{dollar}2\sp\prime{dollar}-bipyridine to 1b gave the platinum(IV) dimer with a free diimine functionality. Reaction of this dimer with {dollar}\rm\lbrack Pt\sb2Me\sb4(\mu{dollar}-{dollar}\rm SMe\sb2)\sb2\rbrack{dollar} gave the mixed oxidation state {dollar}\rm Pt\sb3{dollar} complex with a new reactive {dollar}\rm Me\sb2Pt\sp{lcub}II{rcub}{dollar} centre. Repetition of this cycle gave the {dollar}\rm Pt\sb{lcub}14{rcub}{dollar} dendrimer. The mixed oxidation state {dollar}\rm Pt\sb3{dollar} and {dollar}\rm Pt\sb7{dollar} complexes which possess one reactive {dollar}\rm Me\sb2Pt\sp{lcub}II{rcub}{dollar} centre each, underwent oxidative addition with 1,2,4,5-tetrakis(bromomethyl)benzene to yield dendrimers with 12 and 28 platinum(IV) centres respectively. The {dollar}\rm Pt\sb{lcub}28{rcub}{dollar} complex appears to be the largest transition metal dendrimer yet known.



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