Square grid networks

The use of isonicotinic acid ligands leads to a threefold interpenetrated neutral square grid network in which [Pt(L)2(HL)2] building blocks (L = isonicotinate) (cf. IX), resulting from deprotonation of half of the acid groups, are linked by carboxyl-carboxylate hydrogen bonds (Figure 18) [27c,57]. A network of the same... 

Figure 1 Square grid network formed by ligand 1 and C0CI2.

The formation of the above noninterpenetrated square grid in the EtOH-F O solvent system was studied using different ratios of 2 and Cd(NO)3 [14]. These results indicate that at a 2 Cd(N03)2 ratio of >2.5, the formation of the square grid network was always favored. Notably in this structure the interlayer separation is much smaller (4.8 A versus 6.3 A) than that of above-described structure owing to the absence of large guest molecules. Interestingly, the hydrophobic... 

Figure 2 Interpenetrated square grid network in the crystal structure of [Zn(2)2(H20)2] [SiF6] .

Figure 3 Inclusion of o-dibromobenzene (space filling mode) in square grid networks of 2 and Cd(N03)2.

A larger square grid network than that of 2 was first reported in the product formed between ligand 3 and Fe(II) NCS [18]. In the network the Fe(II) ions are separated by 3 with a distance of 13.66 A. However, the networks are doubly interpenetrated in diagonal-to-diagonal fashion, similar to that of 2 (Figure 2), with an interplanar separation of 11.3 A between the parallel sheets. The solvent (MeOH) molecules occupy the channels formed between the interpenetrated... 

Figure 5 Interpenetration of pyrene network (space filling mode) through the square grid networks of 2 and Ni(N03)2. The coordination and pyrene networks are represented perpendicular and parallel, respectively, to the plane of the paper.

Figure 8 Square grid network exhibited in the complex of 8 and Cul.

The importance of host-guest interactions in the predictable formation of open square grid networks was further exemplified with the reaction of Ni(N03)2 or Cu(N03)2 and ligand 8 in the presence of benzene [21]. With Ni(N03)2 it formed a doubly interpenetrated network as the anthracene moiety prefers to interact with itself rather than with benzene (Figure 9). With Cu(N03)2 it failed to form a 2D network but formed two types of one-dimensional chains. 

In a similar fashion to the above ligands, the ligand 9 was also shown to form an open square grid network containing the largest square cavities reported so far [24], A noninterpenetrated 2D network containing square grids of dimensions 20 x 20 A was obtained when 9 was treated with Ni(N03)2 in the presence of either benzene... 

The square grid network formed between Cd(N03)2 and 2 was shown to catalyze the cyanosilylation of aldehydes [13]. The treatment of benzaldehyde with cyano-trimethylsliane in a CH2C12 suspension of powdered (Cd(2)2(N03)2 n at 40 °C for 24 h resulted in 2-(trimethylsiloxy)phenylacetonitrile in 77% yield. Further, no reaction was observed with powdered Cd(N03)2 or 2 or the supernatant liquid of a CH2C12 suspension of Cd(2)2(N03)2 alone, and also the shape selectivity was observed in catalysis, 2- and 3-tolualdehyde being cyanosilylated in 40 and 19% yields, respectively. These observations indicate that the reaction was promoted heterogeneously by square grid cavities of Cd(2)2(N03)2 . 

Figure 20 Linking of 11 x 11A square grid network with PF6 anions.

Square grid networks generated with bipy spacer ligands were first reported by Fujita et al.46 Fujita s structures are based on Cd(II) and numerous other examples have subsequently been reported based on a number of other transition metals, including Ni(II) and Co(II). Although these 2D coordination networks are essentially identical within the coordination grid (square dimensions ca. 11.5 x 11.5 A), the crystal structures of compounds differ in the mode that networks stack with each other (interlayer separations range from 6-8 A). 

J.T. Culp, J.-H. Park, D. Stratakis, M.W. Meisel, D.R. Talham, Supramolecular Assembly at Interfaces Formation of an Extended Two- Dimensional Coordinate Covalent Square Grid Network at the Air-Water Interface , J. Am. Chem. Soc., 124, 10083 (2002)... 

Desiraju. G.R. Diamondoid and square grid networks 30. in the same structure. Crystal engineering with the iodonitro supramolecular synthon. Cryst. Growth Des. 

Scheme 4 illustrates some of the 2-D network motifs that have thus far been observed in coordination polymers. Square-grid networks (Scheme 4a) exemplify a particularly simple and commonly reported example of a predictable 2-D metal-organic network. Square-grid coordination polymers are based upon 1 2 metahligand complexes with linear bifunctional linkers. Grids with two tjmes of linkers have also been reported, in which rectangular grids are formed (Scheme 4c). ... 

Figure 44 (a) Perspectives view of the square-grid network, showing the two-layer stack in different color. Guest water molecules have been omitted for clarity. Photographs and crystal views around the cobalt ion in as-synthesized crystal ([52], a) and after heating at 150°Cfor24h([52 ],b)... 

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