A1 Journal article (refereed)
A Linear Open-Chain Piperazine-Pyridine Ligand and its meso-helical Co-complex (1998)


Ratilainen, J., Airola, K., Nyrönen, T., & Rissanen, K. (1998). A Linear Open-Chain Piperazine-Pyridine Ligand and its meso-helical Co-complex. Inorganica Chimica Acta, 277, 55-60. https://doi.org/10.1016/S0020-1693(97)06122-7


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Publication details

All authors or editors: Ratilainen, Jari; Airola, Karri; Nyrönen, Tommi; Rissanen, Kari

Journal or series: Inorganica Chimica Acta

Publication year: 1998

Volume: 277

Pages range: 55 - 60

Publication language: English

DOI: https://doi.org/10.1016/S0020-1693(97)06122-7

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Abstract

An oligomeric ligand (HPPy)2P,N,N′-bis[2-(6-(N-(N′-(2-hydroxyethyl)piperazinyl)methyl)]piperazine, was designed to resemble structurally open-chain aza-crowns. Owing to the all-trans configuration of piperazine and pyridine free electron pairs, it should adopt a near linear overall structure in solvent. Theoretical calculations at ab initio level confirm the overall linear structure of free ligand. The crystal structure of the complex [(HPPy)2P][Co(NO3)2]2 shows a contraction from ∼3 to 2 nm structure. Each coordination site creates either a Δ or Δ configuration around the metal ion, thus causing a ligand with an even number of coordination centres to be meso-helical. The complex (C30H48N12O14Co2) crystallizes in the monoclinic space group P21/n (No. 14) with the cell dimensions . The structure is refined to a final agreement factor R(F02) = 0.0576 using 2121 reflections with l>4σ(l). The molecule is centrosymmetric with two identical coordination centres, in which the regular octahedral geometry is tetragonally distorted.


Free keywords: X-ray structure


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