Synthesis and characterization of N-phenyl pyrrole anchored to Fischer carbene complex through ring closing metathesis oxidative aromatization and various aryl substituted Fischer carbene complexes

Ring closing metathesis of pentacarbonyl[(ethoxy)(N,N-diallyl anilyl)carbene]tungsten(0) complex, [(CO)5Wdouble bond; length as m-dashC(OCH2CH3)C6H4N(CH2CHdouble bond; length as m-dashCH2)2], 1 leads to the formation of pentacarbonyl[(ethoxy)(N-phenyl 2,5-dihydro pyrrolyl)carbene]tungsten(0) complex, [(CO)5Wdouble bond; length as m-dashC(OCH2CH3)C6H4N (CH2CHdouble bond; length as m-dashCH2)2], 2 in good yield. Further, complex 2 undergoes oxidative aromatization to afford N-phenyl pyrrole anchored to alkoxy carbene, 3. In addition, a number of aryl substituted carbene complexes [(CO)5Wdouble bond; length as m-dashC(OCH2CH3)C6H4R], 4–7 (4: R = OCH2CH3; 5: R = OCH2CHdouble bond; length as m-dashCH2; 6: R = OCHdouble bond; length as m-dashCHCH2CH2CH2CH2CH3; 7: OC6H5Br) have been synthesized from the reaction of 1-(allyloxy)-4-bromobenzene with W(CO)6 in presence of various concentration of n-BuLi and Meerwein's salt. All the complexes have been isolated in moderate to good yields and have been characterized by 1H NMR, 13C NMR, IR, UV–vis spectroscopic techniques and the solid state structures of 1, 2 and 4 have been unequivocally established by X-ray diffraction analysis

Triazolyl alkoxy fischer carbene complexes in conjugation with ferrocene/pyrene as sensory units: multifunctional chemosensors for lead(II), copper(II), and zinc(II) ions

The regioselective 1,3-dipolar cycloaddition reaction of alkoxy alkynyl Fischer carbene complex 1 with azidomethyl ferrocene 2 and with azidomethyl pyrene 4 under solvent-free conditions yielded the triazolyl Fischer carbene complexes 3 (C27H21O6N3FeW) and 5(C33H21O6N3W), respectively. The cation complexation properties of these receptors have been systematically studied using electrochemical and spectroscopic techniques. The exceptional structural feature existing in these receptors is the presence of a Fischer carbene moiety, connected to the ferrocene or pyrene moiety through a 1,2,3-triazole ring. Receptor 3 contains a redox-active ferrocene moiety and is highly selective toward Pb2+ ion, whereas receptor 5, having a fluorescent pyrene unit, selectively recognizes Zn2+ and Cu2+ ions. The binding ability of receptor 3 can be inferred either from the redox shift (the anodic shift ΔE1/2 = 55 mV) or the highly visual output response for Pb2+ ion. Receptor 5 displays considerable chelation-enhanced fluorescence (CHEF) upon binding with Zn2+ and Cu2+ ions in an aqueous environment. Further, the proposed binding modes of these receptors and their metal cation complexation properties have been supported by 1H NMR titration and MALDI-MS and a DFT study

Triazolyl Alkoxy Fischer Carbene Complexes in Conjugation with Ferrocene/Pyrene as Sensory Units: Multifunctional Chemosensors for Lead(II), Copper(II), and Zinc(II) Ions

The regioselective 1,3-dipolar cycloaddition reaction of alkoxy alkynyl Fischer carbene complex <b>1</b> with azidomethyl ferrocene <b>2</b> and with azidomethyl pyrene <b>4</b> under solvent-free conditions yielded the triazolyl Fischer carbene complexes <b>3</b> (C₂₇H₂₁O₆N₃FeW) and <b>5</b> (C₃₃H₂₁O₆N₃W), respectively. The cation complexation properties of these receptors have been systematically studied using electrochemical and spectroscopic techniques. The exceptional structural feature existing in these receptors is the presence of a Fischer carbene moiety, connected to the ferrocene or pyrene moiety through a 1,2,3-triazole ring. Receptor <b>3</b> contains a redox-active ferrocene moiety and is highly selective toward Pb²⁺ ion, whereas receptor <b>5</b>, having a fluorescent pyrene unit, selectively recognizes Zn²⁺ and Cu²⁺ ions. The binding ability of receptor <b>3</b> can be inferred either from the redox shift (the anodic shift Δ<i>E</i>_1/2 = 55 mV) or the highly visual output response for Pb²⁺ ion. Receptor <b>5</b> displays considerable chelation-enhanced fluorescence (CHEF) upon binding with Zn²⁺ and Cu²⁺ ions in an aqueous environment. Further, the proposed binding modes of these receptors and their metal cation complexation properties have been supported by ¹H NMR titration and MALDI-MS and a DFT study