To Be or Not to Be a (4,4) Net: Reactions of 4′-{4-(N,N-Diethylaminophenyl)}- and 4′-{4-(N,N-Diphenylaminophenyl)}-3,2′:6′,3″- and 4,2′:6′,4″-Terpyridines with Cobalt(II) Thiocyanate

Abstract

The ligands 4′-{4-(N,N-diethylaminophenyl)}-3,2′:6′,3″-terpyridine (1) and 4′{4-(N,N-diphenylaminophenyl)}-3,2′:6′,3″-terpyridine (2) were prepared and characterized, including the single crystal structure of 2. Along with their 4,2′:6′,4″-terpyridine isomers, 3 and 4, ligands 1 and 2 were reacted with Co(NCS)2 under conditions of crystal growth by layering, using solvent mixtures of MeOH and CHCl3. The single crystal structures of [Co(NCS)2(1)]n.0.8nCHCl3, [Co(NCS)2(2)2(MeOH)2].3CHCl3, [Co(NCS)2(3)]n.2nCHCl3, and [Co(NCS)2(4)]n were determined. The complexes with 1, 3, and 4 assemble into 2D (4,4) nets with the Co(II) centres as 4-connecting nodes, whereas [Co(NCS)2(2)2(MeOH)2] is a discrete molecular species, illustrating that MeOH can act as a non-innocent solvent. The effects on the structure of changing from the 3,2′:6′,3″-terpyridine (3,2′:6′,3″-tpy) to a 4,2′:6′,4″-tpy metal-binding unit, and of introducing R2N functionalities with different steric demands, are discussed. PXRD of bulk samples of all four products confirmed the single-crystal structures as representative of the bulk materials.

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

“…This is the same reasoning suggested for the isolation of discrete [Zn 2 (OAc) 4 ( 32 ) 2 ] species for ligand 32 ( Scheme 11) with R= n ‐octyl, n ‐nonyl, n ‐decyl, [60] and n ‐dodecyl [67] . In trans‐ [Co(NCS) 2 (MeOH) 2 ( 64 ) 2 ] ( Scheme 17 for 64 ), ligand 64 is monodentate and the structure resembles those in Figures 36 c and 36d [96] …”

“…We noted above the formation of trans-[Co-(NCS) 2 (MeOH) 2 (71) 2 ] (71 with R = CH 2 Ph) [132] and trans-[Co(NCS) 2 (MeOH) 2 (64) 2 ] [96] in which the presence of (67)] n , [91] [Co-(NCS) 2 (MeOH) 2 (74)] n , [95] and [Co(NCS) 2 (MeOH) 2 (34)] n (34, R = Me, Figure 36e). [97] An analogous scenario is seen in the 1D-chain [Co(OH 2 ) 2 (MeOH) 2 (20)] n .…”

“…[91] Related examples are [Co(NCS) 2 (59) 2 ] n , [91] [Co(NCS) 2 (60) 2 ] n , [47,92] [Co(NCS) 2 (61) 2 ] n , [93] [Co(NCS) 2 (32) 2 ] n (32 with R = Me, Et, n Pr), [92,94] [Co(NCS) 2 ( 27) 2 ] n , [95] [Co(NCS) 2 (62) 2 ] n , [96] and [Co(NCS) 2 (63) 2 ] n . [96] An analogous (4,4) net is also observed in [Fe(NCS) 2 (32) 2 ] n (32 with R = Me). [94] (See Schemes 10, 11, and 17 for ligand structures.)…”

“…[67] In trans-[Co(NCS) 2 (MeOH) 2 (64) 2 ] (Scheme 17 for 64), ligand 64 is monodentate and the structure resembles those in Figures 36c and 36d. [96] Figure 18e showed the 1D-polymer chain in [Ni-(OH 2 ) 4 (56)] n in which the 3,2':6',3"-tpy domain in [56] 2À is ditopic. [83] The introduction of the sulfonate substituents provides potential coordination sites, and in crystallizations using solvothermal conditions, Zhang et al demonstrated the critical role of pH and choice of metal ion in achieving different coordination modes of [56] 2À or [H56] À .…”

“…Compounds incorporating derivatives of 4,2′:6′,4“‐tpy include [Co(NCS) 2 ( 28 ) 2 ] n (see Scheme 11 for 28 ) and the (4,4) net shown in Figure 21 a is typical of this family of 2D‐sheet structures [91] . Related examples are [Co(NCS) 2 ( 59 ) 2 ] n , [91] [Co(NCS) 2 ( 60 ) 2 ] n , [47,92] [Co(NCS) 2 ( 61 ) 2 ] n , [93] [Co(NCS) 2 ( 32 ) 2 ] n ( 32 with R=Me, Et, n Pr), [92,94] [Co(NCS) 2 ( 27 ) 2 ] n , [95] [Co(NCS) 2 ( 62 ) 2 ] n , [96] and [Co(NCS) 2 ( 63 ) 2 ] n [96] . An analogous (4,4) net is also observed in [Fe(NCS) 2 ( 32 ) 2 ] n ( 32 with R=Me) [94] .…”