A novel 2D coordination polymer based on a copper(II) tetramer with p-sulfonated thiacalix[4]arene Qian-Ling Guo a , Wen-Xiang Zhu a, * , Song Gao b , Shu-Lan Ma a , Shu-Jing Dong a , Miao-Qiong Xu a a Department of Chemistry, Beijing Normal University, Beijing 100875, PR China b State Key Laboratory of Rare Earth Materials Chemistry and Application, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China Received 9 December 2003; accepted 17 January 2004 Published online: 7 February 2004 Abstract X-ray structural determination of the title complex shows it containing a phenoxy and sulfato-bridged Cu(II) tetramer coor- dinating to fully deprotonated p-sulfonated thiacalix[4]arene with its cavity occupied by a pyridinium cation and forming a 2D coordination polymer. Variable temperature susceptibility measurement reveals an antiferromagnetic coupling of four Cu(II) ions formed. Ó 2004 Elsevier B.V. All rights reserved. Keywords: Crystal structure; 2D Coordination polymer; Copper tetramer; p-Sulfonated thiacalix[4]arene Calixarenes (1) (Scheme 1) are potentially versatile synthons for the formation of coordination polymers. They can be designed with the sites available for metal binding on the upper and lower rim, as well as at the linker positions, and with ring sizes and conformations that could be used to influence the topolopy and func- tion of networks formed. There are a few examples in which calixarenes of any sort participate in coordination polymers [1–6]. A new class of macrocycles, thiaca- lix[4]arenes (2) has been recently reported [7]. They are derived from 1, and have four sulfur atoms instead of methylene bridges. In its fully deprotonated form, 2 possesses a total of eight donor atoms (four oxygen atoms of phenolic hydroxyl groups and four bridging sulfur atoms) at its lower rim, which may participate in the coordination of metal cations. The 2, which are properly substituted on the upper rim and lower rim, should be suitable for binding metal ions to form co- ordination networks. There is an example, in which Ag þ ions link substituted 2 in the 1,3-alternate conformation to form a 2D coordination polymer [8]. In this paper, we report a novel 2D coordination polymer containing copper(II) tetramer coordinating to 3 in the bowl con- formation. On treatment of an aqueous solution of Na 4 (3) [9] with pyridine and copper sulfate hydrate, dark brown crystals of [Cu 4 (3)(H 2 O) 4 (SO 4 )]  C 5 H 5 NH þ  H 3 O þ  8.5H 2 O(4) were obtained after standing for several weeks [10]. The structure of 4 is shown in Fig. 1(a) [11]. Con- trasting to the transition metal complexes of p-sulfo- natocalix[4]arene [12] and p-sulfonatocalix[5]arene [13] in which pyridine acts as a coligand or guest molecule, in complex 4, the phenolic hydroxyl groups of 3 are fully deprotonated by pyridine. Facile deprotonation of the phenolic hydroxyl groups may be caused by the re- placement of bridging-CH 2 group by sulfur atoms. The deprotonated 3 maintains a conventional bowl confor- mation and a phenoxy-bridged cluster of four Cu(II) ions is formed at the bottom of the bowl. Unlike Cu 4 [thiacalix[4]arene] 2 [14], in which the Cu 4 is close to be square planar, the four Cu(II) ions in our complex * Corresponding author. Tel.: +861062207838; fax: +861062200567. E-mail address: wx-zhu@263.net (W.-X. Zhu). 1387-7003/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2004.01.011 www.elsevier.com/locate/inoche Inorganic Chemistry Communications 7 (2004) 467–470