Semiconductive and Magnetic One-Dimensional Coordination Polymers of Cu(II) with Modified Nucleobases

Four new copper­(II) coordination complexes, obtained by reaction of CuX2 (X = acetate or chloride) with thymine-1-acetic acid and uracil-1-propionic acid as ligands, of formulas [Cu­(TAcO)2(H2O)4]·4H2O (1), [Cu­(TAcO)2(H2O)2]n (2), [Cu3(TAcO)4(H2O)2(OH)2]n·4H2O (3), and [Cu3(UPrO)2Cl2(OH)2(H2O)2]n (4) (TAcOH = thymine-1-acetic acid, UPrOH = uracil-1-propionic acid) are described. While 1 is a discrete complex, 2–4 are one-dimensional coordination polymers. Complexes 2–4 present dc conductivity values between 10–6 and 10–9 S/cm–1. The magnetic behavior of complex 2 is typical for almost isolated Cu­(II) metal centers. Moderate–weak antiferromagnetic interactions have been found in complex 3, whereas a combination of strong and weak antiferromagnetic interactions have been found in complex 4. Quantum computational calculations have been done to estimate the individual “J” magnetic coupling constant for each superexchange pathway in complexes 3 and 4. Compounds 2–4 are the first known examples of semiconductor and magnetic coordination polymers containing nucleobases.

本文报道了四种新型二价铜配位配合物，它们由CuX₂（X=乙酸根或氯离子）分别与配体胸腺嘧啶-1-乙酸（thymine-1-acetic acid，缩写TAcOH）和尿嘧啶-1-丙酸（uracil-1-propionic acid，缩写UPrOH）反应制得，其化学式依次为[Cu(TAcO)₂(H₂O)₄]·4H₂O（1）、[Cu(TAcO)₂(H₂O)₂]ₙ（2）、[Cu₃(TAcO)₄(H₂O)₂(OH)₂]ₙ·4H₂O（3）以及[Cu₃(UPrO)₂Cl₂(OH)₂(H₂O)₂]ₙ（4）。其中配合物1为离散型配合物，而配合物2~4则属于一维配位聚合物。配合物2~4的直流电导率介于10⁻⁶至10⁻⁹ S/cm之间。配合物2的磁学行为近乎符合孤立二价铜金属中心的典型特征；配合物3中存在中弱强度的反铁磁相互作用，而配合物4则同时存在强反铁磁与弱反铁磁相互作用。针对配合物3和4中的每条超交换路径，我们通过量子化学计算估算了各自的“J”型磁耦合常数。配合物2~4是目前已知的首例含核碱基的半导体兼磁学配位聚合物。