Kapoor Pratibha, Pathak Anuradha, Kapoor Ramesh, Venugopalan Paloth, Corbella Montserrat, Rodríguez Montserrat, Robles Juvencio, Llobet Antoni
Department of Chemistry, Panjab University, Chandigarh 160 014, India.
Inorg Chem. 2002 Nov 18;41(23):6153-60. doi: 10.1021/ic025568i.
The complexes [Cu2(mu-Cl)2(Cl)2(L)2] (L = dialkylpyridine-2,6-dicarboxylate; R = Et, L = depc, 1; R = i-Pr, L = dppc, 2) have been prepared and their magnetic properties studied. The crystal structures of complexes 1 and 2 have been solved. Compound 1 belongs to the P space group with Z = 2, a = 8.3020(10) A, b = 9.2050(10) A, c = 10.065(2) A, alpha = 99.040(10), beta = 100.810(10), and gamma = 106.502(10) whereas 2 belongs to the C2/c space group with Z = 8, a = 11.6360(10) A, b = 25.906(3) A, c = 11.76579(10) A, and beta = 107.900(10). The different alkyl ester substitutes produce substantial structural and electronic differences. The Cu2Cl2 core geometry is planar for 1 whereas it adopts a butterfly shape in the case of 2. Furthermore, in 2 the dppc ligand coordinates only by the carbonyl oxygen atoms whereas in 1 the depc ligand coordinates through carbonyl and alkoxy oxygen atoms. Magnetic susceptibility data show a ferromagnetic coupling between the two Cu(II) centers in both cases (J = 39.9(6) cm(-1) for 1, and J = 51.3(5) cm(-1) for 2) with very weak antiferromagnetic interactions (J ' = -0.59 cm(-1) and -0.57 cm(-1) for 1 and 2, respectively). Theoretical calculations at the extended Hückel level have also been carried out to further understand the electronic nature of complexes 1 and 2.
已制备出配合物[Cu2(μ-Cl)2(Cl)2(L)2]（L = 二烷基吡啶-2,6-二羧酸酯；R = 乙基，L = depc，1；R = 异丙基，L = dppc，2）并研究了它们的磁性。已解析出配合物1和2的晶体结构。化合物1属于P空间群，Z = 2，a = 8.3020(10) Å，b = 9.2050(10) Å，c = 10.065(2) Å，α = 99.040(10)，β = 100.810(10)，γ = 106.502(10)；而2属于C2/c空间群，Z = 8，a = 11.6360(10) Å，b = 25.906(3) Å，c = 11.76579(10) Å，β = 107.900(10)。不同的烷基酯取代基产生了显著的结构和电子差异。配合物1中Cu2Cl2核心几何结构为平面型，而在配合物2中则呈蝶形。此外，在配合物2中dppc配体仅通过羰基氧原子配位，而在配合物1中depc配体通过羰基和烷氧基氧原子配位。磁化率数据表明，两种情况下两个Cu(II)中心之间均存在铁磁耦合（配合物1的J = 39.9(6) cm−1，配合物2的J = 51.3(5) cm−1），且存在非常弱的反铁磁相互作用（配合物1和2的J'分别为−0.59 cm−1和−0.57 cm−1）。还进行了扩展休克尔水平的理论计算，以进一步了解配合物1和2的电子性质。
