Studies on synthesis and magnetic resonance of lanthanide complexes with novel Schiff base derived from noncyclic polyether and P-diketone

Nine Ln( Ⅲ ) complexes with a novel Schiff base derived from diglycolamine and benzoylacetone (BZDA) have been synthesized and characterized. They can be formulated as [Ln2(BZDA)3(NO3)3](NO3)3· nH2O(Ln=La, Pr, Nd, Sm, n = 4; Ln=Gd, Tb, Er, Yb, Y, n = l). Enamic form mechanism in this β-diketone Schiff base and its complexes were suggested and proved by IR, UV and NMR methods. The 13C spin-lattice relaxation time T1 and the ratios of r(ci-Ln)/r(cj-Ln) were measured by a 500 MHz NMR instrument for elucidating the formation of the stable sk-membered chelate ring structure in these complexes. The EPR spectrum of the Gd( Ⅲ ) complex exhibits the "U" spectral feature and "zero field effect". On the basis of them, the crystal field strength and the local symmetry around Gd3 in the complex have been discussed.     

Synthesis and catalytic activity of novel heteronuclear Ln(Ⅲ)-Cu(Ⅱ) complexes with noncyclic polyether-amino acid Schiff base

A series of novel heteronuclear Ln(Ⅲ)-Cu(Ⅱ) complexes with noncyclic polyether-amino acid Schiff base were synthesized. The general formula is [LnCu_2(H_2TALY)(NO_3)_5](NO_3)_2' nH_2O(Ln=La, Nd, Sm, Gd, n= 4; Ln=Yb, Y, n=3), where H_2TALY = tetraglycol aldehyde bis-lysine Schiff base. It is the first time to report the synthetic method for this new Cu(Ⅱ) complexes and Ln(Ⅲ)-Cu(Ⅱ) heteronuclear complexes. The complexes were characterized by elemental analysis, IR spectra, TG-DTA, magnetic susceptibility, and especially by a 500 MHz NMR spectrometer for 2D-COSY NMR. Coordination mechanism and structures of complexes have been suggested as well. Of particular interest is the potential that the novel complexes obtained may be used as a catalyst, which prompted us to investigate them. It shows 100% conversion with the viscosity-average molecular weight 120 000 for the polymerization of methyl methacrylate (MMA) without addition of any cocatalyst. Furthermore, the complexes with such aliphatic Schiff bas     

Synthesis and magnetic resonance of new heteropolynuclear Ln(III)-Cu(II) complexes with noncyclic polyether Schiff base

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Ln(Ⅲ)-Ni(Ⅱ)与双水杨醛缩乙二胺席夫碱异核配合物的合成与波谱

合成了双水杨醛缩乙二胺席夫碱（ＳＡＬＥＮ）与镍的配合物Ｎｉ３（ＳＡＬＥＮ）２（ＮＯ３）６·Ｈ２Ｏ及镧系镍的异核配合物Ｌｎ２Ｎｉ３（ＳＡＬＥＮ）６（ＮＯ３）１２·Ｈ２Ｏ（Ｌｎ＝Ｌａ，Ｎｄ，Ｓｍ，Ｇｄ，Ｙｂ，Ｙ）．以紫外、红外光谱、磁化率，特别是１ＨＮＭＲ及ＥＰＲ波谱等方法研究了它们在组成、结构和配位等方面的异同．ＧｄＮｉＳＡＬＥＮ配合物的ＥＰＲ谱表明其在低温ＴＨＦ中呈“单峰效应”．文中讨论了配合物在不同溶剂中峰宽的相对关系、配合物晶体场强度及Ｇｄ３＋周围局部对称性问题     

丝氨酸及其La~(3+)配合物的~1H核磁共振谱参数的pH依赖性

本文测得不同pH值下丝氨酸及其La~(3+)配合物的~1H谱,用PANIC程序对谱图进行模拟,获得化学位移和偶合常数,考察了~1H核磁共振谱参数的pH依赖性,从理论上进行了解释,并由得到的偶合常数计算出丝氨酸及其La~(3+)配合物的三种构象的比例,讨论了它们在不同pH条件下的变化,这些结果为下一步的生物大分子的研究提供了有用的信息。     

α-丙氨酸和L-组氨酸的分子力学计算及其镧系离子配合物结构的NMR研究

应用分子力学计算得到了α-丙氨酸和L-组氨酸在溶液中的分子结构.在此基础上,通过对镧系离子诱导位移的分析和模拟,计算了氨基酸镧系离子配合物的~(13)CNMR准接触位移,模拟了配合物的分子结构.结果表明,在α-丙氨酸镧系离子配合物中,Ce~(3+),Pr~(3+),Nd~(3+)与内氨酸的一个氧原子和一个氮原子形成双齿配位;Sm~(3+),Eu~(3+),Tb~(3+),Dy~(3+),Ho~(3+),Er~(3+),Tm~(3+),Yb~(3+)则与两个氧原子形成双齿配位 在L-组氨酸镧系离子配合物中,Ce~(3+)～Eu~(3+)与组氨酸的两个氧原子和α-氨基的氮原子形成三齿配位,镧系离子Tb~(3+)～Yb~(3+)则与两个氧原子形成双齿配位.同时,还讨论了pH值条件对氨基酸镧系离子配合物结构的影响.     

稀土元素与3,4-二羟基苯甲醛缩邻氨基苯甲酸配合物的合成和表征

本文在三乙胺存在下合成了3,4-二羟基苯甲醛缩邻氨基苯甲酸(H_3L)与稀土元素的配合物。元素分析和摩尔电导值等确定其组成为[REL·nH_2O],(RE=La、Pr、Nd、Sm,n=3;RE=Gd、Dy、Ho、Yb、Y,n=4)。钆和钇配合物皆属重稀土组。磁化率、TG-DTA、IR和NMR等结果表明,配合物中不含硝酸根离子,负三价的配体离子以一种“扭曲”的形式与稀土离子配位。     

多(非汉字符号)C=N-基不对称Schiff碱及其稀土配合物的合成和催化

研究与探讨了多■C=N-基空间不对称Schiff碱的合成,合成了含有2个以上不同位置■C=N-基团的Schiff碱,即四甘醇醛和2,4-二羟基苯甲醛缩双赖氨酸（TBLY）与稀土的配合物,经元素分析、磁化率、光谱及1~HNMR,1~H,1~HCOSY,(13)~CNMR谱等表征,确定其组成为Ln_3（TBLY）（NO)3）)3·nH)2O（Ln=La,n=3;Ln=Nd,n=5;Ln=Gd,Dy,Yb,Y,n=7）.以半经验量子化学AM1法计算并探讨了在红外光谱和核磁共振谱中所观察到的烯胺键的存在.该类新Schiff碱配合物不需助催化剂即可单独催化聚合甲基丙烯酸甲酯（MMA）,转化率可达80％,影均分子量约为22万。