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The synthesis and aggregation behavior of two glycoluril derivatives were descrybed.The crystal of compound 1 belongs to the triclinic system,space group ■,with a=8.946(1),b=13.445(2),c=20.361(3)?,α=89.517(3),β=84.405(3),γ=86.325(3)°,Z=2,V=2432.1(6)?~3,Dc=1.293 g·cm~(-3),C48H34N6O6·2DMSO,Mr=947.07,F(000)=992,μ=0.170 mm~(-1),the final R=0.1606 and wR=0.2410 for 4382 observed reflections(Ⅰ2σ(Ⅰ)).The crystal of compound 2belongs to the monoclinic system,space group P2_1/c,with a=9.500(3),b=24.522(8),c=17.997(6)?,Z=2,V=4054(2)?~3,Dc=1.296 g·cm~(-3),C48H34N6O6,Mr=790.81,F(000)=1648,μ=0.087mm~(-1),the final R=0.2146 and wR=0.2535 for 2878 observed reflections(Ⅰ2σ(Ⅰ)).Unlike the highly conserved R~2_2(8)hydrogen-bonding amide···amide homosynthon,the structural analysis indicated that compound 1 selected the C(20)hydrogen-bonding motif and 2 selected the R~2_2(34)hydrogen-bonding motif,which revealed the competition from remote solvent molecule and the interference of the molecular hydrocarbon core in crystal packing.The supramolecular structure revealed molecule 1 is further linked into a one-dimensional chain and 2 into a two-dimensional interwoven plane by N–H···N hydrogen bonds. 相似文献
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三算结合教学不仅是改革教学体系的一项科学实验.而且是改革教学方法,促进教育学有机结合的一项科学实验.它避免了片面的教与学的关系,克服了满堂灌。教材本身的编排,设计、有利于发挥教师的主导作用和学生的主体作用。促进师生的双边活动。 相似文献
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“三算”结合教改实验,符合小学数学教学大纲的精神,符合素质教育的要求。教学中以口算为基础,笔算为主体,珠算为工具。通过口算、珠算、笔算的有机结合,相互促进,使学生手脑并用,活动多样。从而促进儿童由感性到理性,由具体到抽象的转 相似文献
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以价廉易得的己二酸二甲酯为原料, 在甲醇钠的催化下, 通过Dieckmann缩合反应得到2-氧代环戊烷羧酸甲酯, 收率82.2%; 2-氧代环戊烷羧酸甲酯再与丙烯腈在40%(质量比)苄基三甲基氢氧化铵甲醇溶液存在下, 经Michael加成制得1-(2-氰乙基)-2-氧代环戊烷羧酸甲酯, 收率82.5%; 进一步酸性脱羧得到3-(2-氧代环戊基)丙腈, 收率84.0%; 将脱羧产物通入装有Ni-Cu/γ-Al2O3催化剂的固定床反应器中, 催化环合最终得到6,7-二氢-5H-1-氮茚, 反应总收率33.8%. 相似文献