1036766-33-2Relevant articles and documents
Synthesis, structures, and coordinating properties of phosphole-containing hybrid calixpyrroles
Nakabuchi, Takashi,Matano, Yoshihiro,Imahori, Hiroshi
, p. 3142 - 3152 (2008)
Symmetrie and asymmetric hybrid calixpyrroles containing a σ4-phosphole or σ4-2,3-dihydrophosphole unit (symmetric and asymmetric (σ4-P,N2,X-hybrids: X = S, O) were prepared by using acid-promoted condensation reactions of the corresponding σ4-phosphatripyrranes with 2,5-bis(1-hydroxy-1- methylethyl)heteroles. The X-ray crystallographic analyses of the symmetric and asymmetric σ4-P,N2,X-hybrids show that the cavity sizes of the σ4-P,N2,S-hybrids are larger than those of the σ4-P,N2,O-hybrids, mainly reflecting the difference in edge-to-edge distances of the thiophene and furan rings. The symmetric σ4-P,N2,X-hybrids and the asymmetric σ4-P,N2,S-hybrid were successfully converted to the corresponding σ3 forms by reductive desulfurization at the phosphorus center. Each of the symmetric σ3-P,N 2,X-hybrids was obtained as a mixture of two conformers, where the lone pair of the phosphorus atom is located inside (in) and outside (out) the cavity. The interconversion between the in and out type conformers of die asymmetric σ3-P,N2,S-hybrid was sufficiently slow to isolate each of them. The complexation reactions of the symmetric σ3-P,N2,S-hybrid with Au(I), Pt(II), and Pd(II) ions afforded both of the in and out type complexes, where the in type complexes were the diermodynamically favored products. In the complexation reactions of the asymmetric σ3-P,N2,S-hybrids, the stereochemistry at the phosphorus center was retained to give the in or out type complex exclusively. In the in-in type trans-M(II)-bis(phosphine) complexes (M = Pt, Pd) derived from the symmetric and asymmetric σ3-P,N 2,S-hybrids, the M-Cl fragment is bound above the cavities of the two macrocycles. The crystal structures and the 1H NMR spectra of these M(II) complexes reveal that the P,N2,S-hybrid calixpyrroles bind the M-Cl fragments through P-M coordination and cooperative NH-Cl hydrogen-bonding interactions.
