کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1312200 1499171 2014 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Rationalizing the formation and versatility of multinuclear metal complexes of bis(1-methyluracil-5-yl)methane as hybrids between classical calix[n]arenes and metallacalixaromatics
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Rationalizing the formation and versatility of multinuclear metal complexes of bis(1-methyluracil-5-yl)methane as hybrids between classical calix[n]arenes and metallacalixaromatics
چکیده انگلیسی


• Metallacalix[n]arenes derived from cis-a2MII and bis(1-metyluracil-5-yl)methane.
• Isomeric (rotamer and linkage) variations of metallacalix[n]arenes.
• Metallacalix[n]arenes with inherent chirality and stacked dimetal units.

Metallacalix[n]arenes are a distinct class of metallacyclic compounds consisting of heteroaromatic rings L and square-planar cis-a2MII entities (M = Pt or Pd; a = NH3 or amine; or a2 = chelating diamine) instead of methylene bridges as in the classic calix[n]arenes. Here a series of hybrid compounds is described, which simultaneously have bridging –CH2– as well as cis-a2MII units, and uracil containing ligands L. Specifically, L = bis(1-methyluracil-5-yl)methane (1) and in one case a derivative of it, bis(1-methyluracil-5-yl)methylbenzene (2), have been reacted with cis-[a2M(H2O)2]2+ (with a = NH3 or a2 = 2,2′-bipyridine or bis(pyrazloyl-1-yl)propane) in water and products were isolated. Altogether X-ray crystal structures of eight metallacycles (complexes 3–6, 8–11) of M2L2, M4L2, and M6L6 stoichiometries have been determined as well as a second modification of 1. In all closed metallacycles the 1-methyluracil entities are deprotonated with metals coordinating via N3 positions, and without exception the uracil rings adopt 1,3-alternate conformations. A special feature of ligand 1 in its twofold deprotonated form is its propensity to bind additional metal ions through its exocyclic oxygen functionalities. While O4 sites appear to be favored as secondary metal binding sites, linkage isomerism and involvement of O2 is likewise possible (compounds 4, 9, 10). On the basis of the X-ray crystal structures, a reaction scheme is proposed which accounts for the different stoichiometries observed.

Metallacyclic species based on the bis(1-methyluracil-5-yl)methane ligand and cis-a2MII entities (M = Pt or Pd; a = NH3 or a2 = chelating heteroaromatic diamine) are reported and their structural diversity is pointed out. They are to be considered hybrids between classical (organic) calix[n]arenes and metallacalix[n]arenes.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Inorganica Chimica Acta - Volume 417, 1 June 2014, Pages 274–286
نویسندگان
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