Complexation of Triorganotin Derivatives of [18]Crown-6- and [15]Crown-5-(benzo-4-carboxylate) with Alkali Thiocyanates

Abstract

Investigations of the simultaneous complexation of tri-n-butyltin and triphenyltin derivatives of [18]crown-6- or [15]crown-5-(benzo-4-carboxylate) by the anion and cation from NaSCN or KSCN are reported. The crystal structure of [Na+ is included in [15]crown-5-C6H3-4-COOSn(C6H5)3NCS]-], 4 NaSCN, displays an unusual zwitterionic nature with one intramolecular charge separation characterized by an Na-Sn distance of 9.29(1) A, and several intermolecular charge separations, the shortest being 5.48(1) A. Similar distances (9.70(2), 9.28(2), intramolecular; 5.40(2) and 5.41(2) A, shortest intermolecular) are observed in the more complicated structure of the corresponding [18]crown-6-(benzo-4-carboxylate) derivative, 3 NaSCN, with two independent molecules in the asymmetric unit. For the tri-n-butyltin analogues 1 and 2, complex equilibria were observed in acetone and unraveled by variable temperature 13C, 117Sn. and 23Na NMR studies. Their complexes with KSCN and NaSCN undergo decomposition in acetone solution, as evidenced by the transformation of [K+ is included in [18]crown-6-[C6H3-4-COOSn(nBu)3NCS]-], into tri-n-butyltin isothiocyanate and a novel dimeric potassium [18]crown-6-(benzo-4-carboxylate), the structure of which was elucidated by X-ray diffraction analysis.

Di-n-butyltin oxide as a chemical carbon dioxide capturer

“…Tables 1 and 2 provide the complete NMR assignments for compounds 1 and 2 respectively. The 2 J ( 1 He 119 Sn) coupling constants being larger than the 3 J ( 1 He 119 Sn) ones in the butyl chains is unusual, since in most cases the inverse holds [22], but not unique, since also very similar 2 J ( 1 He 119 Sn) and 3 J ( 1 He 119 Sn) [23] coupling constants following the sequence as mentioned here [24] have been described.…”

Ion pair receptors

“…The resulting complexes were characterized by their unusual zwitterionic nature ( i.e. , a degree of intramolecular charge separation), which is reflected in a relatively large distance between the Na + cation and the formally negatively charged tin center 35. A combination of 1 H NNR and 117 Sn NMR spectroscopy, as well as X-ray crystal structural analyses, established that for NaSCN and KSCN, respectively, the Na + and K + cations are complexed by the crown ether component, whereas the NCS − anion interacts with the Sn atom (Fig.…”

An Overview of Forty Years Organotin Chemistry Developed at the Free Universities of Brussels ULB and VUB

“…40 The interactions of diethyltin dichloride and of watersoluble tri-or diorganotin polyoxaalkanecarboxylates with DNA (fragments) was recently undertaken. 41,42 Around pH 7, almost no interaction is detected. The target of in vitro antitumour-active organotin compounds is being investigated.…”