Three novel 25,27-dihydroxy-26,28-bis(3-benzylselenopropoxy)-5,11,17,23-tetra-tert-butylcalix[4]-arene (2), 25,27-dihydroxy-26,28-bis[3-(2-hydroxyethylseleno)propoxy]-5,11,17,23-tetra-tert-butyl-calix[4]arene (3) and 25, 27-dihydroxy-26,28-bis(3-propylselenopropoxy)-5,11,17,23-tetra-tert-butyl-calix[4]arene (4) were synthesized for the comparison of their ion-selectivity in ion-selective electrodes (ISE). X-ray structure of the CH/pi complex of 4(.)CH(2)Cl(2) was elucidated. ISEs based on 2-4 as neutral ionophores were prepared, and their selectivity coefficients for Ag+ (log K-Ag,M(pot)) were investigated against some main group metal ions and transition metal ones using the fixed interference method (FIM). These ISEs showed excellent Ag+ selectivity over most of the interfering cations examined. It is evident that the stronger Hg2+ interference may not be produced while hard donors (hydroxy) are close to the soft selenium donors.
Transition metal complexes of stable N-heterocyclic carbenes have recently gained increasing attention as pre-catalysts for a number of important reactions primarily based on the analogy between N-heterocyclic carbenes and strong ó-donating tertiary phosphines,[1] Although a large number of transition-metal carbene complexes have been reported, very few incorporate chelating carbenes were reported.[2,3] Therefore, we have set out to prepare and study transition-metal compounds with chelating di-N-heterocyclic carbenes, and we now report new dicationic tetra(carbine)nickel(Ⅱ) complexes in this class (Scheme 1). Their structures have been determined by single-crystal X-ray diffraction studies (Figure 1).……
The nature of the highly polar P-N bond in phosphinimine makes a ligand of this kind become versatile in both coordination and organometallic chemistry.[1,2] Usually this kind of phosphinimine phosphine P,N-heterodifunctional ligands is prepared by the Staudinger reaction of azides with organophophine. Now a more mild and efficient method is provided. The product of Mannich reaction of 2-aminopyridine reacted with Ph2PCl in the presence of Et3N, giving the phosphinimine compound 1 in more than 90% yield.……
The multi-dentate ligands and their complexes have attracted more and more interests in supramolecular chemistry and catalysis.[1,2] Recently, we found a convenient and efficient method to synthesize this kind of P,N-ligands. The C-Hor C-Cl bond in N-heterocycle was activated in presence of corresponding organophospine reagent and the HCl elimination was fluent, giving the multi-dentate P,N-ligands.……
The crystal structure of the title complex, Mo(CO)4(NNP), (NNP=2-(N-cyclohexyl- N-diphenylphosphinomethyl)aminopyridine) has been determined, and its crystallographic data are as follows: triclinic, space group P , a = 9.135(1), b = 9.772(1), c = 17.000(2) , a = 76.377(2), b = 78.333(2), g = 67.243(2)? Mr = 582.44, V = 1349.7(3) 3, Z = 2, Dc = 1.433 g/cm3, m(MoKa) = 0.581 mm-1 and F(000) = 596. A total of 5614 reflections were collected in the range of 2.30< q < 25.03? of which 4721 were independent (Rint = 0.0176) and 4159 observed reflections (I ≥ 2s(I)) were used in the refinement. R = 0.0326 and wR = 0.0867. The Mo centre is six-coordinated by four carbonyls (MoC 1.938(4), 2.003(4), 2.019(4), 2.035(4) ) and P, N atoms from the ligand (MoP 2.4812(8), MoN 2.349(3) ?. The coordination geometry of the complex can be described as an octahedron.
