Secondary Hypervalent I(III)···O Interactions:  Synthesis and Structure of Hypervalent Complexes of Diphenyl-λ³-iodanes with 18-Crown-6

Abstract

Reported here for the first time are the synthesis and characterization of supramolecular complexes between diaryl-lambda(3)-iodanes and 18-crown-6 (18C6). Slow evaporation of solvents afforded 1:1 and 2:1 complexes between Ph(2)IBF(4) and 18C6 as stable crystals, depending on the conditions. X-ray crystal structures of these complexes indicated that each iodine atom contacts with the three adjacent oxygen atoms of 18C6 through two hypervalent secondary bonding and a weak interaction. (1)H NMR analyses and CSI-MS spectra showed that, in dichloromethane solution, Ph(2)IBF(4) exclusively forms the 1:1 complex with 18C6 (binding constant K(a), 1.02 x 10(3) M(-)(1)). The binding constants decrease with the increased solvent donor ability (Gutmann's DN). Changing the heteroatom ligand from BF(4) to the less nucleophilic PF(6) and AsF(6) increased the binding constant by about six times. Substitution of an electron-withdrawing group onto the para position of Ph(2)IBF(4) tends to increase in the complex stability. A linear Hammett relationship (rho = 0.59) between log K(a) and sigma(p)(+) values of substituents indicates that the diaryl-lambda(3)-iodanes with electropositive iodine(III) interact more efficiently with 18C6. Decreased binding magnitude was measured with 15C5, dibenzo-18C6, dibenzo-21C7, and dibenzo-30C10.

Charge‐Assisted Chalcogen Bonds: CSD and DFT Analyses and Biological Implication in Glucosidase Inhibitors

“…[28] Similarly,t he halogen atom in hypervalent halonium salts forms two covalent bondsa nd two s-holes are present on the halogen opposite to these bonds. As expected, thesec ompounds form in the solid state two charge assisted halogen bonds with anions [29] or Lewis bases [30,31] and in solution are remarkablye ffective catalysts. [31] a-Glucosidasei nhibitors are antihyperglycemic drugs used to treat type2diabetes.…”

“…As expected, thesec ompounds form in the solid state two charge assisted halogen bonds with anions [29] or Lewis bases [30,31] and in solution are remarkablye ffective catalysts. [31] a-Glucosidasei nhibitors are antihyperglycemic drugs used to treat type2diabetes. [32][33][34] These are used to control blood glucose levels by inhibiting digestive a-amylases and a-glucosidases thusdelaying the absorption of glucose intothe bloodstream.…”

Polyvalent iodine in organic chemistry: Recent developments, 2002–2005

“…X-ray crystal 1:1 or 2:1 structures of these complexes indicate that each iodine atom contacts with three adjacent oxygen atoms of 18-crown-6 through two hypervalent secondary bondings and a weak interaction [88]. 1 …”

“…However, application of IBX is restricted because of its potentially explosive nature and extremely low solubility. Several research groups have tried to improve IBX by structurally modifying it [87,88] or by developing the polymer-supported analogs [89,24]. The problem of insolubility can also be solved by using an elevated reaction temperature [90], adding a suitable catalyst [23], performing the reaction in an ionic liquid and water [21], using derivatives of IBX amides [22] and esters [91,92].…”

Ventricular septal rupture masquerading as coronary perforation during intervention for acute myocardial infarction

“…Recently, we reported that some organo‐λ 3 ‐iodanes form discrete complexes with crown ethers through cooperative hypervalent interactions between iodine(III) and the oxygen atoms of crown ethers 2. Depending on the conditions, diphenyl(tetrafluoroborato)‐λ 3 ‐iodane (Ph 2 IBF 4 ) affords stable crystalline 1 : 1 and 1 : 2 complexes with 18C6 9. The iodine(III) atom of the complexes contacts the three adjacent oxygen atoms of 18C6 through hypervalent secondary bonding.…”