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In many cases, the fluorescentchemosensors have been made through the combination of areceptor molecule and a fluorophore. Owing to their selec-tive complexation with metal species, macrocyclic ligandsmake them ideal candidates for the receptor molecules.However, the introduction of such cyclic receptors is oftenlimited by high cost and the synthetic complexity. The alter-nate way to avoid such limitations is to develop the acyclicanalogues for the cyclic receptors. Our interest has focusedon the dipodal receptors containing quinoline moietybecause this receptor has shown not only similar behaviorswith cyclic receptors

Self-assembly of the dipodal ligand L and CdX 2 (X = ClO 4 and NO 3 ) produced unique pseudo-cyclic complexes (A) [Cd(L)(H 2 O)(CH 3 OH)](ClO 4 ) 2 ( 1 ) and [Cd(L)(H 2 O)(NO 3 )](NO 3 ) ( 2 ), respectively. From the stepwise reaction of the pseudo-cyclic complexes (A) followed by coligands (B) such as 4,4′-bipyridine and terephthalate, the controlled one-dimensional coordination polymer {[Cd(L)(H 2 O)(bpy)](ClO 4 ) 2 (MeOH) 0.5 } n ( 3 ) with (A–B) n array and the discrete “dumbbell”-like complex [Cd 2 (L) 2 (tp)(H 2 O) 2 ](tp)(H 2 O) 9 ( 4 ) with (A–B–A) patterns were isolated.

Self-assembly of CuI and 1,12-diphenyl-5,8-dioxa-2,11-dithiadodecane ( L ), a podal ligand with S 2 O 2 donor set, afforded a unique square-grid type coordination polymer [Cu 4 I 4 L 2 ] n ( 1 ). X-ray analysis of 1 shows that cubane-like Cu 4 I 4 clusters are located at the nodes of the square-grid and connected to four ligands by Cu–S bonds forming a layer structure. The layers are stacked with an ABAB sequence. Photoluminescence behavior of 1 was also investigated.

The crystals with high quality forX-ray analysis were obtained by the vapor diffusion ofdiethyl ether into the DMSO solution of the precipitates.Crystal parameters and procedural information correspond-ing to data collection and structure refinements are given inTable 1. The geometric parameters of the complex are shownin Table 2.According to X-ray crystal structure analysis (Figure 1),the discrete cyclodimeric complex, [Ag(1)]

The NO2S2-donor macrocycle (L1) was synthesised from the ring closure reaction between Boc-N-protected 2,2′-iminobis(ethanethiol) (3) and 2,2′-(ethylenedioxy)bis(benzyl chloride) (4) followed by deprotection of the Boc-group. α,α′-Dibromo-p-xylene was employed as a dialkylating agent to bridge two L1 to yield the corresponding N-linked product (L2). The X-ray structure of L2 (as its HBr salt) is described. A range of Cd(II) and Hg(II) complexes of L1 (6–9) and L2 (10–12) were prepared and characterised. Reaction of HgX2 (X = Br or I) with L1 afforded [Hg(L1)Br]2[Hg2Br6]·2CH2Cl26 and [Hg(L1)I2] 7, respectively. For 6, the Hg(II) ion in the complex cation has a distorted tetrahedral coordination environment composed of S2N donor atoms from L1 and a bromo ligand. In 7 the coordination geometry is highly distorted tetrahedral, with the macrocycle coordinating in an exodentate manner via one S and one N atom. The remaining two coordination sites are occupied by iodide ions. [Hg(L1)(ClO4)]ClO48 was isolated from the reaction of Hg(ClO4)2 and L1. The X-ray structure reveals that all macrocyclic ring donors bind to the central mercury ion in this case, with the latter exhibiting a highly distorted octahedral coordination geometry. The O2S2-donors from the macrocyclic ring define the equatorial plane while the axial positions are occupied by the ring nitrogen as well as by an oxygen from a monodentate perchlorato ion. Reaction of Cd(NO3)2·4H2O with L1 afforded [Cd(L1)(NO3)2]·0.5CH2Cl29 in which L1 acts as a tridentate ligand, binding exo-fashion via its S2N donors. The remaining coordination positions are filled by two bidentate nitrate ions such that, overall, the cadmium is seven-coordinate. Reactions of HgX2 (X = Br or I) with L2 yielded the isostructural 2 : 1 (metal : ligand) complexes, [Hg2(L2)Br4] 10 and [Hg2(L2)I4] 11. Each mercury ion has a distorted tetrahedral environment made up of S and N donors from an exodentate L2 and two coordinated halides. Contrasting with this, the reaction of L2 with Cd(NO3)2·4H2O yielded a 1-D coordination network, {[Cd2(L2)(NO3)4]·2CH2Cl2}n12 in which each ring of L2 is exo-coordinated via two S atoms and one N atom to a cadmium ion which is also bound to one monodentate and one bidentate nitrate anion. The latter also has one of its oxygen atom attached to a neighboring cadmium via a nitroso (µ2-O) bridge such that the overall coordination geometry about each cadmium is seven-coordinate. The [Cd(L2)0.5(NO3)2] units are linked by an inversion to yield the polymeric arrangement.