Preparation and characterization of [[M(dmb)2]TCNQ.xTCNQo]n polymers (M=Cu,Ag; dmb = 1,8-diisocyano-p-menthane; x = 0, 0.5, 1.0, 1.5; TCNQ = 7,7,8,8-tetracyano-p-quinodimethane) and design of new semi- and photoconducting organometallic materials.
New thermoplastic organometallic materials of the type [[M(dmb)2]TCNQ.xTCNQo.y solvent], (M = Cu(I), Ag(I); dmb = 1,8-diisocyano-p-menthane; TCNQ = 7,7,8,8-tetracyano-p-quinodimethane, x = 0, 0.5, 1.0, 1.5; solvent = none, THF or toluene) have been prepared and characterized from X-ray powder diffraction patterns, X-ray crystallography (for some Ag polymers), DSC, and conductivity measurements. While the [[M(dmb)2]TCNQ.xTCNQo]n polymers (M = Cu,Ag; x = 0, 0.5) are insulating, the others (x = 1.0 and 1.5) are semiconducting, and the relative conductivity is found to be a function of the molecular weight and crystallinity. The [[Cu(dmb)2]TCNQ.1.5TCNQ]n material is also photoconducting, while the Ag analogue is not. Photochemical and luminescence quenching experiments in the solid-state established that the Cu+ center and TCNQo act as electron donor and acceptor, respectively, in this photoprocess. Finally photocells of the type glass/SnO2/[Cu(dmb)2]TCNQ.TCNQo]n + 0.5 acceptor/Al (acceptor = TCNQo, C60 and TCNN (13,13,14,14-tetracyano-5,12-naphthacenequinodimethane)) have been designed and characterized. The quantum yields (number of photoproduced electrons/number of photons) are as follows: TCNQ, 1.6 x 10(-4), C60, 5 x 10(-5), TCNN, 3.0 x 10(-4) at lambdaexc = 330 nm. X-ray data for [[Ag(dmb)2]TCNQ.2THF]n: space group P2(1/c), monoclinic, a = 13.5501(10), b = 9.9045(10), c = 32.564(2) A, beta = 91.130(10) degrees, Z = 4. X-ray data for [[Ag(dmb)2]TCNQ.0.5TCNQo.0.5 toluene]n: space group P2(1/c), monoclinic, a = 14.3669(19), b = 9.1659(3), c = 34.012(3) A, beta = 92.140(8) degrees, Z = 4. X-ray data for [[Ag(dmb)2]TCNQ.1.5TCNQo]n: space group C2/c, monoclinic, a = 25.830(11), b = 9.680(2), c = 42.183(19) A, beta = 104.87(4) degrees, Z = 8. X-ray data for [[Ag(dmb)2]DCTC]n: space group P2(1/a), monoclinic, a = 26.273(3), b = 9.730(3), c = 31.526(3) A, beta = 112.12(2)degrees, Z = 4.
Département de Chimie, Université de Sherbrooke, Québec, Canada.
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