کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1339033 | 979689 | 2009 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Single stranded helical supramolecular architecture with a left handed helical water chain in ternary copper(II) tryptophan/diamine complexes Single stranded helical supramolecular architecture with a left handed helical water chain in ternary copper(II) tryptophan/diamine complexes](/preview/png/1339033.png)
The ternary copper(II) complexes [Cu(l-trp)(bpy)](ClO4) (1) and [Cu(l-trp)(phen)] (ClO4) · 3H2O (2) (where l-trp = l-tryptophan, bpy = bipridyl, phen = phenanthroline) have been synthesized. The single crystal X-ray structures for these complexes revealed that the monocationic CuII-units are interlinked through Cu–OCO–Cu connectivity and exist as helical coordination polymers. The two different helical strands composed with Cu1 and Cu2 independently, possess a similar pitch distance of 7.713 Å in complex 1. For complex 2, existing in the hydrated form, the Cu(II) polymeric strand and the hydrated water molecules have gained a supramolecular helical architecture with a similar pitch distance of 8.133 Å. The two helical strands in complex 1 are associated with right handed (PP) supramolecular chirality, while the helical water chain and the CuII-strand in 2 are self assembled into left handed (MM) helicity in the solid state. The solid state CD recorded for 1 and the dehydrated form of 2 exhibit a positive optical sign at their respective d–d band [λmax = 667 nm, 1; λmax = 630 nm, 2], the solution state CD for both these complexes are found to be inverted into a negative optical sign, which could be attributed to inversion of their associated supramolecular helicity. The TGA curve illustrates two distinct weight losses at 60 °C and 87 °C, equivalent to one and two water molecules, respectively. The PXRD pattern for the hydrated and dehydrated forms of 2 indicated a change, on comparison with the simulated diffractograph. The fluorescence properties of both these complexes, possessing tryptophan and bipy/phen, were investigated.
Two single stranded helical coordination polymers with [Cu(DA(AA)] complexes are reported. The left handed helical water chain entrapped in between the CuII-helical strand is investigated and the change in the supramolecular helical architecture and the change in the chiroptical properties are correlated using various chiral components such as (P)/(M), (Λ/Δ), and λ/δ in detail, along with CD spectra, single crystal X-ray structures, and thermo-analytical techniques.Figure optionsDownload as PowerPoint slide
Journal: Polyhedron - Volume 28, Issue 2, 3 February 2009, Pages 245–252