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A heptacyclic carbocycle possessing three p-quinodimethane units conjugated in one plane has been synthesized and shown to exhibit distinct biradical characteristics. The molecule has a HOMO/LUMO band gap of ca. 1 eV and a S(0)-T(1) energy gap of 2.12 kcal/mol, and it absorbs and emits near-IR light at room temperature. It is air-stable under ambient light for several months and thermally stable up to 160 °C under nitrogen, and it undergoes reversible two-electron oxidation and reduction. The synthetic approach is such that a smaller and larger oligo-p-quinodimethane can be synthesized.  相似文献   
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质环的求导和交换性   总被引:3,自引:0,他引:3       下载免费PDF全文
In this paper, we generalize some corresponding results of [1-4]. We obtain the main results as the following:Theorem 1 Let R be a prime ring of characteristic not 2 with nontrivial derivations d1,d2 and let U be a nonzero ideal of R . If C is the center of R, then the following conditions are equivalent : (i)d1,d2(x)∈C for all x∈U; (ii) [d1(x),d2(y)]∈C for all x,y∈U; (iii) d1(x)d2(y)+d2(x)d1(y)∈C for all x,y∈U; (iv) R is commutative.Theorem 2 Let R be a prime ring with nontrivial derivations d1,d2,…, dn and U be a nonzero ideal of R. Let C be the center of R. If d1(x1)d2(x2)…dn(xn)∈C for all x1, x2…xn)∈U, then R is commutative.  相似文献   
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