Crystal Structure of a Cyclic Polyether Complex of Alkali Metal Thiocyanate

Bright, D.; Truter, Mary R.

doi:10.1038/225176a0

Cited by 76 publications

(21 citation statements)

References 8 publications

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“…Picrate analogs are superior to even such lipid-soluble anions as hexanoate; the trinitrocresolate anion was found to be the most potent (although it dramatically reduces the selectivity of valinomycin as well). The SCN-anion has been found to be closely associated with the co-ordinated Rb + ion in X-ray crystallographic studies of the RbSCN-dibenzo-13crown-6 polyether complex (Bright & Truter, 1970). The SCN-ion is inserted from above the ring in this ion-pair complex.…”

Section: Discussionmentioning

confidence: 99%

Raman spectroscopic study of the valinomycin-KSCN complex

Asher

Rothschild

Stanley

1974

Journal of Molecular Biology

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This paper reports the first Raman spectroscopic study of the potassium complex of the cation-specific antibiotic valinomyoin.Complete Raman spectra (140 to 3000 cm-l) of crystalline valinomycin-KSCN and its Ccl,, CHCl, and CaHSOH solutions are presented and used to probe the structure of the complex in these environments. In all oases a single, narrow peak is observed in the ester C=O stretch region (1750 to 1775 cm-l) which contrasts strongly with the broad bands observed in solutions of uncomplexed valinomyoin. This is consistent with the presence of a single conformation in which all six ester C= 0 groups co-ordinate an enclosed potassium ion. We find that although the ester C=O stretch frequencies of the complex are similar in the solid state and in non-polar solution (~1770 cm-l) they are considerably different in the presence of polar solvents (~1756 cm-l); this may indicate that the complexed potassium ion is still free to interact with nearby solvent ions (and possibly its counterion) through gaps in the hydrophobic "shield"provided by the hydrocarbon residues of valinomycin.In contrast the amide C=O frequencies of the complex (~1660 cm-l) are solvent-independent.These groups are apparently strongly hydrogen-bonded to provide a rather rigid, compact framework for the complex conformation.

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Section: Discussionmentioning

confidence: 99%

Raman spectroscopic study of the valinomycin-KSCN complex

Asher

Rothschild

Stanley

1974

Journal of Molecular Biology

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“…Extraktionsreaktion (15) : (15) Dementsprechend gilt : und Aij : Gleichgewichtskonstante der Reaktion (15). (16) [15] stimmen mit (29) und (29a) erwartungsgemass bis auf den Faktor /zj I Uj/ / Z i I ui uberein. Die in (29) und (32) aufgezeigte Konzentrationsabhangigkeit der Selektivitatskoeffizienten K r t fur zi # zj ist auch experimentell beobachtet worden [17]. Demnach ist die Tabellierung von sogenannten Selektivitatskonstanten nur dann sinnvoll, wenn die Messbedingungen in allen Einzelheiten angefuhrt werden.…”

Section: L)unclassified

“…Demnach ist die Tabellierung von sogenannten Selektivitatskonstanten nur dann sinnvoll, wenn die Messbedingungen in allen Einzelheiten angefuhrt werden. Anhaltspunkte uber den Einfluss der Storionenaktivitat auf die Selektivitat eines Sensors rnit konstantem Innenableitsystem ergeben sich aus (29) bzw. (32) :…”

Section: L)unclassified

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Modellberechnung der EMK und der Ionenselektivität von Membranelektroden‐Messketten

Wuhrmann¹,

Morf²,

Simon³

1973

Helvetica Chimica Acta

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Based upon a set of clearly specified assumptions, a universal integral cquation is derived which describes the steady-state E M F of an electrochemical cell containing any type of ion-selective membrane electrode. The various modes of delineating the phenomenon ion-selectivity by an explicit function are shown. For all types of analytically important ion-sensitive electrodes, thc selectivity between monovalent cations and anions, respectively, can be neatly and comprehensively rationalized. These theoretically derivable expressions are compiled.

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“…However, the flexibility of 1,4,7,10-tetraoxacyclododecane heterocycle suggests a potential to adapt its conformation to varied stereochemical requirements and thus lend itself to the formation of other coordination polyhedra. To test hypotheses, and to ascertain whether there exist similarities to 1 : 1 complexes of certain 18-membered macrocycles (Bright & Truter, 1970;Herceg & Weiss, 1970) (in which the cations are held in the central cavities of the rings), we are undertaking the structure determination of complexes of 1,4,7,10-tetraoxacyclododecane with some small cations. A single-crystal X-ray diffraction study of an anhydrous 1:1 complex formed by this heterocycle with CuC12 is reported below.…”

Section: Introductionmentioning

confidence: 99%

The crystal structure of the complex of 1,4,7,10-tetraoxacyclododecane with copper(II) chloride

Remoortere¹,

Boer²,

Steiner³

1975

Acta Crystallogr Sect B

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The crystal structure of C8H1604. CuCI2, the complex of 1,4,7,10-tetraoxacyclododecane with copper(II) chloride has been determined by a single-crystal X-ray diffraction study. The compound crystallizes in the space group P21212~ with a= 7-062 (3), b= 13.661 (8), and c= 12.337 (7) ,~ (Z= 4). The intensities of 1565 unique reflections were measured on a Picker automatic diffractometer (Mo Kct radiation) and the structure was solved by Patterson and Fourier methods. All hydrogen atoms were located. Fullmatrix least-squares refinement of atom positions, hydrogen isotropic temperature factors and anisotropic thermal parameters for all other atoms converged at a final RI = 3"4 % for the 1038 reflections above background. The Cu(II) ion is hexacoordinate and its coordination geometry can be pictured as an elongated and distorted octahedron, where two cis sites are taken by chlorine atoms and the remaining vertices are occupied by the four oxygens of the macrocycle. The equatorial plane of the coordination polyhedron coincides with a non-crystallographic mirror plane and contains the copper atom, two chlorines and two oxygens in a square-planar pattern. The Cu-Cl bond lengths are 2-214 (2) and 2.228 (2) A and the Cu-O distances are 2.128 (3) and 2.113 (3)/~. The apical Cu-O bonds are much longer, 2-343 (4) and 2.403 (3) A respectively, and the angle between them is only 135.2 ° compared with 180 ° in an ideal octahedron.

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Crystal Structure of a Cyclic Polyether Complex of Alkali Metal Thiocyanate

Cited by 76 publications

References 8 publications

Raman spectroscopic study of the valinomycin-KSCN complex

Raman spectroscopic study of the valinomycin-KSCN complex

Modellberechnung der EMK und der Ionenselektivität von Membranelektroden‐Messketten

The crystal structure of the complex of 1,4,7,10-tetraoxacyclododecane with copper(II) chloride

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