Additions and corrections
An unprecedented all helical 3D network and a rarely
observed non-interpenetrated octahedral network in homochiral
Cu(II) MOFs: effect of steric
bulk and π–π stacking interactions of the ligand backbone
Subhabrata Banerjee, N. N. Adarsh and Parthasarathi
Dastidar*
CrystEngComm, 2009, 11, 746 (DOI: 10.1039/b820087b). Amendment published 7th September 2010
The authors would like to correct and clarify the mistake in the crystal structure of MOF-2 reported in the above manuscript.
Correction: MOF 2 whose chemical formula was assigned as [{Cu(µ-L2)2(µ-Cl)}·xH2O]n is now corrected and the correct formula of MOF 2 is [{Cu(µ-L2)2(µ-Cl)} ·Cl·H2O]n because of the following reasons.
In the reported structure of MOF 2, we removed the contribution of smeared electron density which we presumed to be due to the disordered water molecules (solvates) by applying SQUEEZE of PLATON suite. However, in the re-examination of the structure, we realized that part of the smeared electron density must be due to counter anion Cl- which was need to balance the +2 charge of the metal center Cu. Accordingly, we refined the structure and found that a Cl- counter anion is located around a 4-fold symmetry axis and disordered over two positions with SOF of 0.10165 and 0.14835 resulting into overall SOF of 0.25 meaning that the Cl- is rotationally disordered around the 4-fold symmetry. We also located a water molecule having SOF of 0.25 around the 4-fold symmetry. In the final cycle of refinement, we also found few smeared electron densities, which could not be modelled. Thus, the overall structure as far as coordination network is concerned remains the same. The only difference is in the content of the lattice included solvent molecules and the needed counter anion Cl- to have the charge balance. It may be pointed out that the TG data do not match with the X-ray structure presumably due to the smeared electron densities that could not be modelled. The elemental analysis data also matched well with this corrected formula: Anal. calcd for C28H28N8O4Cl2Cu.H2O (%): C 48.53, H 4.36, N 16.17. found: C 48.72, H 4.65, N 16.33. The crystal data for the corrected structure of MOF-2: C28H30Cl2CuN8O5, M = 693.04, tetragonal, space group P4 (no. 75) a = 13.266(4), b = 13.266(4), c = 5.3885(17) Å. V = 948.3(5) Å3, T = 100 K, Z = 1. Dc = 1.214 g cm-3. F(000) = 357, λ (Mo Kα) = 0.71073Å, µ = 0.759 mm-1, 2θmax = 46.52°, 7648 reflections measured, 1333 observed [I > 2σ(I)] 99 parameters; Rint = 0.0543, R1 = 0.1075; wR2 = 0.2980 (I > 2 σ(I)), R1 = 0.1103; wR2 = 0.3056 (all data) with GOF = 1.094
The Royal Society of Chemistry apologises for this error and any consequent inconvenience to authors and readers.