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Conductivity-based sensory devices built on electrically conductive polymers have proved to offer great promise towards the detection of a wide variety of analytes.[1] Selective chemoresistive responses have been demonstrated with charge localization, [2] planarization/twist of the polymer backbone to modify conjugation length, [3] and segmental energy matching/mismatching of the polymer backbone.[4] We have been interested in developing new chemoresistive methods to determine blood electrolyte levels that are diagnostic in determining the physiological condition of individuals. In particular, the determination of Ca 2+ ion concentration has attracted interest as a growing number of ionochromic sensors for this ion have been developed. [5] However, in view of the importance of this analyte new systems with enhanced specificity, better signal/noise ratios, and alternative sensory platforms remain a topic of interest. Herein, we report a new approach to produce a selective ionoresistivity resulting from a charge-specific interaction between the segmented conducting-polymer backbone and the bound metal ion.We have previously reported a proton-doped calix[4]arene-based conducting polymer, formed by oxidative polymerization of monomer 2.[6] The conductivity of the polymer film relies on rapid self-exchange between the discrete electroactive units attached to the upper (wider) rim of the calix[4]arene. To have this process be sufficiently fast, a condition for high conductivity, all of the phenolic oxygen atoms need to be maintained in their protonated state to ensure that the redox centers have equivalent energy levels and chemical structures. The high sensitivity of the resistivity to the chemical state of lower-rim phenolic oxygen atoms suggested to us that new sensory materials could be produced by designing specific cationic interactions with these centers. Herein we report our investigation of related polymers derived from monomer 1 (Scheme 1) which integrate a recognition site through the calix[4]arenecrown-5 moiety, a motif that has been demonstrated to provide differential binding of metal cations. [7][8][9][10] Monomer 1 was synthesized by a pathway similar to that we reported for 2 by using palladiumcatalyzed cross-coupling methodology. [6,11,12] To determine the binding of various metal ions, we treated monomer 1 with 10 equivalents of the respective salts, and the proton NMR spectra of the solutions revealed significant changes, as summarized in Table 1. To assert that these effects are the result of metal-ion binding, we confirmed that there was no change to the proton NMR spectra of 1 on the addition of (nBu) 4 NPF 6 , a non-binding electrolyte. In addition, we observed that solutions of 2 displayed no spectroscopic differences with these metal-ion salts, which indicates that the difference in the NMR shifts is not simply due to an enhanced ionic strength.The resonances assigned to the -CH 2 -bridge (Ar-CH 2 -Ar) of the calix[4]arene remain a pair of doublets in the presence of alkali-metal ions, but th...

Using a unique three-solvent biphasic method, we have prepared and characterized three new fully conjugated, chalcogen-rich, bridged copper(II) complexes for the preparation of molecular conductors and magnetic materials, having the general formula (Bu(4)N)(2){tto[Cu(L)](2)} (tto = C(2)S(4)(2)(-) = tetrathiooxalato; L = mnt = C(4)N(2)S(2)(2)(-) = 1,2-dicyanoethene-1,2-dithiolato for complex 2, dsit = C(3)Se(2)S(3)(2)(-) = 2-thioxo-1,3-dithiole-4,5-diselenolato for complex 3, dmid = C(3)OS(4)(2)(-) = 2-oxo-1,3-dithiole-4,5-dithiolato for complex 4a). The single-crystal X-ray structures of 2 and 3 have been determined: 2, (Bu(4)N)(2){tto[Cu(mnt)](2)}, monoclinic, space group C2/m, a = 19.549(4) Å, b = 13.519(3) Å, c = 10.162(2) Å, beta = 90.33(1) degrees, Z = 2; 3, (Bu(4)N)(2){tto[Cu(dsit)](2)}, monoclinic, space group P2(1)/c, a = 9.903(1) Å, b = 15.589(1) Å, c = 18.218(1) Å, beta = 90.40(1) degrees, Z = 2. Complex 2 displays perfect planarity, while 3 shows a slight tetrahedral distortion at the metal centers, resulting in a dihedral angle of 24.86(3) degrees. Cyclic voltammetry of (Bu(4)N)(2){tto[Cu(mnt)](2)} (2), (Bu(4)N)(2){tto[Cu(dsit)](2)} (3), and (Bu(4)N)(2){tto[Cu(dmid)](2)} (4a) shows each complex to exhibit two reversible redox processes which can be attributed to {tto[Cu(L)](2)}(2)(-) right arrow over left arrow tto[Cu(L)](2)}(-) and {tto[Cu(L)](2)}(1)(-) right arrow over left arrow {tto[Cu(L)](2)}(0) couples. The structural and electronic properties of 2, 3, and 4a will be compared to those of the recently communicated analogous complex (Bu(4)N)(2){tto[Cu(dmit)](2)} (1).