Synthesis and Characterization of Monomeric Magnesium and Zinc complexes supported by 1,5,9-Trimesityldipyrromethene for use in polymerization studies
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The Ohio State University / OhioLINK
2011
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1308265029 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu13082650292021-08-03T06:03:15Z Synthesis and Characterization of Monomeric Magnesium and Zinc complexes supported by 1,5,9-Trimesityldipyrromethene for use in polymerization studies Wambua, Pasco M. Chemistry Organic Chemistry Polymer Chemistry Polymers Lactide Polymerization Grgnard reagents Magnesium complexes Zinc complexes <p>Magnesium and zinc complexes supported by a bulky bidentate ancilliary ligand have been synthesized and characterized. The compounds (pyac)MgnBu(THF),1; (pyac)Zn(nBu),2; (pyac)Mg(CH2CH2Ph)(THF), 3; (pyac)ZnEt, 4; and (pyac)MgOBut(THF),5; where pyac = 1,5,9 – trimesityl dipyrromethene ligand , are all moisture and air sensitive. The n – butyl group in compounds 1, 2 and 3 showed unexpected α – 1H NMR pattern in solution that may be simulated as an AA’XX’ pattern. Single crystal X-ray diffraction studies carried out on 1 and 5 revealed a distorted tetrahedral structure about the metal centre. Compounds 1, 2 and 5 react with 13CO2 forming carboxylates.</p><p>Preliminary polymerization studies showed that all compounds initiate and sustain ring opening polymerization of lactides and ε-caprolactone. However, the zinc alkyls were comparatively very slow when compared to the magnesium alkyls. Compound 1 exhibited good stereocontrol in the polymerization of rac and L – Lactide resulting in heterotactic and isotactic polylactide respectively.</p><p>Reaction of compound 1 with benzophenone results in the formation of an alkoxide with the elimination of 1 - butene. In the case of Grignard reagents (depending on the R group), the same reaction gives tertiary alcohol, or a mixture of secondary and tertiary alcohol. The reactivity mechanism of compound 1 proceeds exclusively via β – hydrogen transfer. However, presence of a β – hydrogen in the R group of the Grignard reagents results in secondary alcohol as the majority product. If the R group is a methyl the tertiary alcohol is exclusively obtained.</p> 2011-09-12 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1308265029 http://rave.ohiolink.edu/etdc/view?acc_num=osu1308265029 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Chemistry Organic Chemistry Polymer Chemistry Polymers Lactide Polymerization Grgnard reagents Magnesium complexes Zinc complexes |
| spellingShingle |
Chemistry Organic Chemistry Polymer Chemistry Polymers Lactide Polymerization Grgnard reagents Magnesium complexes Zinc complexes Wambua, Pasco M. Synthesis and Characterization of Monomeric Magnesium and Zinc complexes supported by 1,5,9-Trimesityldipyrromethene for use in polymerization studies |
| author |
Wambua, Pasco M. |
| author_facet |
Wambua, Pasco M. |
| author_sort |
Wambua, Pasco M. |
| title |
Synthesis and Characterization of Monomeric Magnesium and Zinc complexes supported by 1,5,9-Trimesityldipyrromethene for use in polymerization studies |
| title_short |
Synthesis and Characterization of Monomeric Magnesium and Zinc complexes supported by 1,5,9-Trimesityldipyrromethene for use in polymerization studies |
| title_full |
Synthesis and Characterization of Monomeric Magnesium and Zinc complexes supported by 1,5,9-Trimesityldipyrromethene for use in polymerization studies |
| title_fullStr |
Synthesis and Characterization of Monomeric Magnesium and Zinc complexes supported by 1,5,9-Trimesityldipyrromethene for use in polymerization studies |
| title_full_unstemmed |
Synthesis and Characterization of Monomeric Magnesium and Zinc complexes supported by 1,5,9-Trimesityldipyrromethene for use in polymerization studies |
| title_sort |
synthesis and characterization of monomeric magnesium and zinc complexes supported by 1,5,9-trimesityldipyrromethene for use in polymerization studies |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2011 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1308265029 |
| work_keys_str_mv |
AT wambuapascom synthesisandcharacterizationofmonomericmagnesiumandzinccomplexessupportedby159trimesityldipyrrometheneforuseinpolymerizationstudies |
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1719430101359132672 |