1D and 2D NMR studies of isobornyl acrylate - Methyl methacrylate copolymers
1D and 2D NMR studies of isobornyl acrylate - Methyl methacrylate copolymers
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DOI：
10.1016/j.molstruc.2011.07.046
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发表时间：
2011-10-12
影响因子：
3.8
通讯作者：
Shankar, Ravi
中科院分区：
文献类型：
--
作者：
Khandelwal, Deepika;Hooda, Sunita;Shankar, Ravi
以2-溴丙酸甲酯为引发剂，PMDETA铜配合物为催化剂，在70℃氮气气氛下，采用原子转移自由基聚合法（ATRP）合成了不同组成的丙烯酸异铜酯-甲基丙烯酸甲酯（B/M）共聚物。(1)采用核磁共振波谱法确定共聚物的组成。然后用共聚物组成来确定单体的反应性比。用线性Kelen-Tudos法（KT）和非线性变量误差法（EVM）测定B/M共聚物共单体的反应率分别为r(B) = 0.41 +/- 0.11, r(M) = 1.11 +/- 0.33, r(B) = 0.52, r(M) = 1.31。利用偏振转移（DEPT）、二维异核单量子相干（HSQC）等技术，对I H和（13）C{(1)H})核磁共振谱进行了完整的共振赋值。通过二维全相关光谱（TOCSY）进一步确认二维HSQC分配。B和M单元的羰基碳和M单元的甲基碳被分配到三元组成和构型序列，而β -亚甲基碳被分配到四元组成和构型序列。同样，B单元的甲基碳被分配到五元水平。利用二维异核多键相关（HMBC）光谱详细研究了羰基碳和季碳与甲基、亚甲基和甲基质子共振的1,3和1,4键序耦合。(C) 2011年Elsevier B.V.出版
Isobornyl acrylate - methyl methacrylate (B/M) copolymers of different compositions were synthesized by atom transfer radical polymerization (ATRP) using methyl-2-bromopropionate as an initiator and PMDETA copper complex as catalyst under nitrogen atmosphere at 70 degrees C. (1)H NMR spectrum was used to determine the compositions of copolymer. The copolymer compositions were then used to determine the reactivity ratios of monomers. Reactivity ratios of co-monomers in B/M copolymer, determined from linear Kelen-Tudos method (KT) and non linear Error-in-Variable Method (EVM), are r(B) = 0.41 +/- 0.11, r(M) = 1.11 +/- 0.33 and r(B) = 0.52, r(M) = 1.31 respectively. The complete resonance assignments of I H and (13)C{(1)H}) NMR spectra were carried out with the help of Distortion less Enhancement by Polarization Transfer (DEPT), two-dimensional Heteronuclear Single Quantum Coherence (HSQC). 2D HSQC assignments were further confirmed by 2D Total Correlation Spectroscopy (TOCSY). The carbonyl carbon of B and M units and methyl carbon of M unit were assigned up to triad compositional and configurational sequences whereas beta-methylene carbons were assigned up to tetrad compositional and configurational sequences. Similarly the methine carbon of B unit was assigned up to pentad level. 1,3 and 1,4 bond order couplings of carbonyl carbon and quaternary carbon resonances with methine, methylene and methyl protons were studied in detail using 2D Hetero Nuclear Multiple Bond Correlation (HMBC) spectra. (C) 2011 Published by Elsevier B.V.