Bolz Ina, Spange Stefan
Chemnitz University of Technology, Institute of Chemistry, Strasse der Nationen 62, 09111 Chemnitz, Germany.
Chemistry. 2008;14(30):9338-46. doi: 10.1002/chem.200800626.
The use of hydrogen-bonding patterns in the same way as is known from DNA building blocks is a challenge for the construction of novel types of suitable chromophoric probes. This feature has been utilised for the construction of a novel type of UV/Vis probe for detection of supramolecular AAD or DAD sequences (A=hydrogen bond acceptor, D=hydrogen bond donor). Here we report on the structure of the enolisable chromophore 1-n-butyl-5-(4-nitrophenyl)barbituric acid (1), which has an adjustable hydrogen-bonding pattern. The position of the keto-enol equilibrium of this dye is strongly influenced both by the solvent polarity and by the chemical environment. Furthermore, the recognition properties of the barbiturate were examined by the use of seven artificial receptors: the pyridine bases 2,6-diaminopyridine (DAP), 2,6-diacetamidopyridine (DAC) and 2,6-bis(trifluoroacetamido)pyridine (TFA), as well as the nucleic acid bases 9-ethyladenine (EtAd), 9-ethylguanine (EtGu), 1-n-butylcytosine (BuCy) and 1-n-butylthymine (BuTy). It was found that 1 can interact with these bases either through acid-base interaction or by hydrogen-bonding complexation. The balance between the interactions is dependent both on the basicity strength and on the presence of a suitable recognition sequence in the base. The induced formation of the enol form of 1 thus causes a significant UV/Vis shift as function of the nature of the base.
以与DNA构建模块中已知方式相同的方式使用氢键模式，对于构建新型合适的发色探针而言是一项挑战。这一特性已被用于构建一种新型紫外/可见探针，用于检测超分子AAD或DAD序列（A =氢键受体，D =氢键供体）。在此，我们报道了可烯醇化的发色团1-正丁基-5-(4-硝基苯基)巴比妥酸(1)的结构，其具有可调节的氢键模式。该染料的酮-烯醇平衡位置受到溶剂极性和化学环境的强烈影响。此外，通过使用七种人工受体研究了巴比妥酸盐的识别特性：吡啶碱2,6-二氨基吡啶(DAP)、2,6-二乙酰氨基吡啶(DAC)和2,6-双(三氟乙酰氨基)吡啶(TFA)，以及核酸碱9-乙基腺嘌呤(EtAd)、9-乙基鸟嘌呤(EtGu)、1-正丁基胞嘧啶(BuCy)和1-正丁基胸腺嘧啶(BuTy)。发现1可以通过酸碱相互作用或通过氢键络合与这些碱基相互作用。相互作用之间的平衡既取决于碱强度，也取决于碱基中合适识别序列的存在。因此，1的烯醇形式的诱导形成导致显著的紫外/可见光谱位移，这是碱基性质的函数。
