Trinodal Self‐Penetrating Versus cds 3‐Dimensional Networks Using Bis(3,2’ : 6’,3’’‐terpyridine) Building Blocks: the Solvent Makes the Difference

Abstract

Reactions between Co(NCS) 2 and 2 4 ,2 4 -[2,5-bis(cyclohexyloxy)-1,4-phenylene]di(1 3 ,2 2 : 2 6 ,3 3 -terpyridine) (1), 2 4 ,2 4 -[2,5-bis(cyclohexylmethoxy)-1,4-phenylene]di(1 3 ,2 2 : 2 6 ,3 3 -terpyridine) (2), and 2 4 ,2 4 -[2,5-bis(2-phenylethoxy)-1,4-phenylene]di(1 3 ,2 2 : 2 6 ,3 3 -terpyridine) ( 3) under conditions of crystal growth by layering at room temperature lead to 3-dimensional nets with either a cds or trinodal self-penetrating topology depending upon the solvents (MeOH/C 6 H 5 Cl, MeOH/1,2-Cl 2 C 6 H 5 , or MeOH/CHCl 3 ) used in the crystallization experiments. The cds network was found for [Co(NCS) 2 (1)] n •2nC 6 H 4 Cl 2 , [Co(NCS) 2 (2)] n •4nC 6 H 4 Cl 2 , and [Co(NCS) 2 (3)] n •2.5nC 6 H 5 Cl, while a trinodal selfpenetrating net was observed in [Co 2 (NCS) 4 (2) 2 ] n •5.5nCHCl 3 •0.2nMeOH. Preliminary structural data for single crystals from the reactions of Co(NCS) 2 and 1 or Co(NCS) 2 and 3 from MeOH/CHCl 3 solvent combinations also evidenced the assemblies of trinodal self-penetrating nets. Both net topologies assemble from a combination of planar, 4-connecting metal and ligand nodes. The role of the solvent in directing the network type is investigated.

Does the Central Nitrogen Atom Make a Difference? A Comparison of Non‐Coordinating Pyridine and Benzene Spacers in Multitopic Ligands

“…Table 3 summarizes the series of [Co(NCS) 2 ( 70 )] n ⋅ n Solv coordination compounds which adopt cds nets. In each case, the 3,2′:6′,3“‐tpy domains exhibit conformation II ( Scheme 4 and Figure 32 b ), and the 3D‐network is remarkedly tolerant to changes in the spatial requirements of the R groups [132–134] …”

“…The data in Table 3 revealed self-interpenetrating net with (6 2 .8 4 )(6 4 .8 2 )(6 5 .8) 2 topology. [133,135] The three compounds crystallize in the monoclinic C2/c space group with very similar cell parameters, and Figure 33a is representative of the coordination environments of the two crystallographically independent ligands 70 in each compound. Figure 33a illustrates that each 3,2':6',3"-tpy unit adopts conformation II (Scheme 4).…”

“…[135] The preference between the assembly of this 3D-net and the cds net described in the last section is solvent driven, and we have proposed that the solvent-accessible cavities accessible in the trinodal self-interpenetrating net are compatible with small molecules such as CHCl 2 and MeOH, but not ClC 6 H 5 or 1,2-Cl 2 C 6 H 4 . [133]…”

“…We have also seen that for R= n octyl in 70 , a cds net is produced in [Co(NCS) 2 ( 70 )] n when crystals are grown from 1,2‐C 2 C 6 H 4 /MeOH, whereas a pts net resulted when the crystallization solvents were CHCl 3 /MeOH. Interestingly, other crystallizations by layering using Co(NCS) 2 in MeOH and ligands 70 in CHCl 3 led to [Co(NCS) 2 ( 70 )] n ⋅ xn MeOH ⋅ yn CHCl 3 (R=3‐methyl‐ n ‐butyl, x =1, y =3; R=2‐ethyl‐ n ‐butyl, x =0.8, y =1.8; R=CH 2 Cy, x =0.1, y =2.75) with an unusual trinodal self‐interpenetrating net with (6 2 .8 4 )(6 4 .8 2 )(6 5 .8) 2 topology [133,135] . The three compounds crystallize in the monoclinic C 2/ c space group with very similar cell parameters, and Figure 33 a is representative of the coordination environments of the two crystallographically independent ligands 70 in each compound.…”