Isomers of Terpyridine as Ligands in Coordination Polymers and Networks Containing Zinc(II) and Cadmium(II)

Abstract

The use of divergent 4,2’:6’,4”- and 3,2’:6’,3”-terpyridine ligands as linkers and/or nodes in extended coordination assemblies has gained in popularity over the last decade. However, there is also a range of coordination polymers which feature 2,2’:6’,2”-terpyridine metal-binding domains. Of the remaining 45 isomers of terpyridine, few have been utilized in extended coordination arrays. Here, we provide an overview of coordination polymers and networks containing isomers of terpyridine and either zinc(II) and cadmium(II). Although the motivation for investigations of many of these systems is their luminescent behavior, we have chosen to focus mainly on structural details, and we assess to what extent assemblies are reproducible. We also consider cases where there is structural evidence for competitive product formation. A point that emerges is the lack of systematic investigations.

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

“…The 4,2 :6 ,4 -terpyridine (4,2 :6 ,4 -tpy) metal-binding domain has increased in popularity as a building block in coordination polymers and networks, while 3,2 :6 ,3 -terpyridines (3,2 :6 ,3 -tpy) are less well examined [1][2][3][4]. The introduction of functional groups in the 4 -position of the tpy unit is synthetically straightforward, and provides a means of tuning the properties of the ligands and their coordination complexes.…”

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

“…The use of 3,2' : 6',3''-terpyridines (= 1 3 ,2 2 : 2 6 ,3 3 -terpyridines), in coordination chemistry has gained in popularity over the last decade, although this isomer of terpyridine remains less well exploited than the bis(chelating) 2,2' : 6',2''-terpyridine (= 1 2 ,2 2 : 2 6 ,3 2 -terpyridine) and the divergent 4,2' : 6',4''-terpyridine (= 1 4 ,2 2 : 2 6 ,3 4 -terpyridine; Scheme 1). [1][2][3][4][5] The coordination chemistry of derivatives of 3,2' : 6',3''-tpy was first explored by Grafino et al who reported the structure of [Zn 2 (μ-4'-Ph-3,2' : 6',3''-tpy)(acac) 4 ]•H 2 O (4'-Ph-3,2' : 6',3''-tpy = 4'-phenyl-3,2' : 6',3''-terpyridine;…”

Adapting (4,4) Networks through Substituent Effects and Conformationally Flexible 3,2’:6’,3”-Terpyridines

“…A further 47 isomers of tpy can be drawn, and eleven of these retain a chelating 2,2'-bipyridine (bpy) metal-binding domain (e.g., 2,2':4',4"-tpy, Scheme 1) [6]. 4,2':6',4"-Terpyridine (4,2':6',4"-tpy) and 3,2':6',3"-terpyridine (3,2':6',3"-tpy) are noteworthy in being divergent building blocks, appropriate for the formation of coordination polymers and networks [7,8]. Interestingly, these ligands only coordinate to metal ions through the outer pyridine rings.…”