Abstract
Compound (I), idealized as Br4Co3O14N8C16H41 (see text), crystallizes in the triclinic space groupP¯ 1 (No. 2) with cell constants ofa=7.4470(7),b=7.9648(4),c=15.2223(8),α=96.338(4)ℴΒ=93.504(6)ℴ,γ=112.894(6)ℴ,V=821.328 å3, and d(calc; MW=1065.97,z=1)=2.155 gm-cm−3. Data (3880 total reflections) were collected over the range 2ℴ ≤ 2θ ≤ 55ℴ and corrected for absorption (Μ=63.69 cm−1) using data from Psi scans. The unexpectedly isolated compound contains a [cis-Co(en)2Br(OH)]+ cation, while the anion contains a central Co(III) surrounded by two mondentate,trans-squarato ligands, twotrans-hydroxo, and two waters. The waters and hydroxy ligands were identified by determining, experimentally, the presence and positions of their respective hydrogens. Given the need for overall electroneutrality, one squarato ligand must be a dianion (Sq2−) and the other a monoanion (SqH−); however, since the ion bearing the squarato ligands sits at an inversion center, the hydrogen of the latter must be disordered. Refinement of the heavy atoms with anisotropic thermal parameters and fixed hydrogen positions (B's fixed at) led to the finalR(F) andR W(F) factors of 0.036 and 0.042, respectively. (I) was obtained during efforts to prepare [Co(en)2(squarate)]Br by the displacement of two chloro ligands from the coordination sphere of [cis-Co(en)2Cl2]Cl by K2 (squarate) followed by addition of NaBr. Compound (I) appears to be the first example of a coordination compound in which squarate2− and squarate H− anions are present as ligands to a transition metal ion. A search of the Cambridge file (to 1992) produced no known examples of Co(III) squarates. Thus, (I) appears to also be the first example of its kind.
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References
Bernal, I.; Cetrullo, J.; Myrczek, J.; Massoud, S. S.J. Coord. Chem., in pres.
Bailar, J. C. Jr.,Inorganic Syntheses; McGraw-Hill: New York, 1946; Vol. 2., p. 223.
Galbraith Laboratories, Inc., 2323 Sycamore Dr., Knoxville, TN 37921.
CAD4.V5 is the Enraf-Nonius Corporation X-ray diffraction data acquisition program, version of 1991.
The NRCVAX Crystal Structure System, A. C. Larson, F. L. Lee, Y. LePage, M. Webster, J. P. Charland & E. J. Gabe, as adapted for PC use by Peter S. White, University of North Carolina, Chapel Hill, NC.
Roof, R. B.A Theoretical Extension of the Reduced Cell Concept in Crystallography, Report LA-4038, Los Alamos Scientific Laboratory, 1969.
Cromer, D. T.; Waber, J. T.International Tables for X-ray Crystallography; The Kynoch Press: Birmingham, England, 1975; Vol. IV, Tables 2.2.8 and 2.3.1, respectively, for the scattering factor curves and the anomalous dispersion values.
Bernal, I.; Cetrullo, J.; Jackson, W. G.J. Coord. Chem. 1993, 28, 89.
Bernal, I.J. Coord. Chem. 1987,15, 337.
Bernal, I.; Cetrullo, J.; Myrczek, J.J. Coord. Chem.,1993,30, 367.
Solans, X.; Aguiló, M.; Gleizes, A.; Faus, J.; Julve, M.; Verdaguer, M.Inorg. Chem. 1990,29, 775.
Bull, R. J., Ladd, M. F. C., Povey, D. C., Shirley, R.Cryst. Struct. Comm. 1973,2, 625.
Julve, M.; Faus, J.; Verdaguer, M.; Gleizes, A.,J. Am. Chem. Soc.,1984,106, 8306 and also in Gleizes, A.; Julve, M.; Verdaguer, M.; Real, J. A.; Faus, J.; Solans, X.,J. Chem. Soc.,1992, 3209.
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Cai, J., Bernal, I., Fronczek, F. et al. Ligand displacement reactions from the coordination sphere of cobalt complexes. Part II: The displacement of ligands of [cis-Co(en)2Cl2]Cl by potassium squarate. The crystal and molecular structure of a compound with idealized formula of [cis-Co(en)2(H2O)Br]2[trans-(C2O4 2−(C2O4H−)Co-trans-(H2O)2(OH)2]Br2 (I). Struct Chem 7, 233–240 (1996). https://doi.org/10.1007/BF02281234
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DOI: https://doi.org/10.1007/BF02281234