نتایج جستجو برای: 12-Crown-4
تعداد نتایج: 1723592 فیلتر نتایج به سال:
The new compound [K–(12C4)2]2[K–12C4]2[Sn9]·4en (1), where 12C4 is 12-crown-4 polyether, was crystallized from an ethylenediamine solution of an intermetallic precursor with nominal composition K4Li2Sn8. The structure of the compound (orthorhombic, Cmca, a = 21.763(4), b = 16.030(3), c = 51.85(1) Å, Z = 8) contains isolated deltahedral clusters of [Sn9]4−. The clusters are of Cs symmetry and ar...
مطالعات تئوری در این پروژه به سه دسته تقسیم می شود: 1-مطالعات تئوری بر روی ساختار و پروتون خواهی: 12-crown-4 ، 15-crown-5، 18-crown-6 و کمپلکس های na li+, وk مربوطه 2- محاسبه ثابت های تشکیل کمپلکس های اترهای تاجی فوق با li , na و k در حلال های مختلف 3- مطالعات تئوری روی برهمکنش کمپلکس های اتر تاجی [m(12-crown-4)]+ (+(m+=li+, na+, k+ با یون های هالید (f-, cl-, br-) و نیزتعدادی از مولکول های...
Four half-sandwich type mononuclear lanthanide crown ether complexes with the formula [Ln(12-crown-4)(NO3)3] (Ln3+ = Dy3+ (1), Tb3+ (2), Ho3+ (3), and Er3+ (4); 12-crown-4 = 1,4,7,10-tetraoxacyclododecane) were successfully synthesized and structurally characterized. Ac magnetic susceptibility measurements reveal that dysprosium complex 1 behaves as a typical single-ion magnet, while solid stat...
Diazahexathia-24-crown-8 (2) has been isolated from the reaction mixture during the preparation of monoazatrithia-12-crown-4 (1). When N-Boc protected bis(2-chloroethyl)amine was employed as a starting material, N-Boc protected monoazatrithia-12-crown-4 (3) and N-Boc protected diazahexathia-24-crown-4 (4) were separated easily. Double-armed diazahexathia-24-crown-8 having two 3',5'-dichlorobenz...
The first hybrid crown ether with two adjacent disilane fragments was synthesized through reaction of O(Si2Me4Cl)2 (3) with O(C2H4OH)2. By means of DFT calculations, the complexation ability of 1,2,4,5-tetrasila[12]crown-4 (7) towards Li+ was determined to be considerably higher compared to [12]crown-4.
The two new ozonide compounds K([12]crown-4)2O3 · 1.5 NH3 (1) and Rb([12]crown-4)2O3 · 1.5 NH3 (2) were synthesized from the binary alkali metal ozonides and [12]crown-4 in liquid ammonia. The airand temperature-sensitive red, needle-shaped compounds crystallize isostructurally in the non-centrosymmetric space group Fdd2 (no. 43) with 16 formula units per unit cell. The lattice parameters are a...
The extraction-separation of lanthanum and europium ions with bis(2-ethylhexyl) phosphoric acid (DEHPA) in cyclohexane was improved by adding 12-crown-4 (12C4) to the aqueous phase as a masking agent. In the presence of this crown ether the extraction curve of lanthanum ions versus pH shifts to the higher pH region, while the curve is not influenced for the europium ions. Consequently the separ...
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