Steric control of supramolecular association in structures of Zn(S₂COR)₂withN,N′-bis(pyridin-4-ylmethyl)oxalamide

Abstract

The crystal and molecular structures of the one-dimensional coordination polymer [Zn(S2COEt)2(4LH2)]n (1) and binuclear [Zn(S2COCy)2]2(4LH2) (2) are described, where 4LH2 is N,N′-bis(pyridin-4-ylmethyl)ethanediamide. In 1, the Zn(S2COEt)2 entities are linked by bidentate bridging 4LH2 ligands through the pyridyl-N atoms to generate a twisted supramolecular chain. As a result of monodentate xanthate ligands, the N2S4 donor set defines a distorted tetrahedral coordination geometry and, crucially, allows the participation of the non-coordinating sulfur atoms in supramolecular association. Thus, in the crystal amide-N–H···O(amide) and amide-N–H···S(thione) hydrogen bonds link chains into a three-dimensional architecture. The substitution of the ethyl group in the xanthate ligand with a cyclohexyl group results in very different structural outcomes. In 2, a binuclear molecule is observed with the coordination geometry for zinc being defined by chelating xanthate ligands and a pyridyl-N atom with the NS4 donor set defining a highly distorted geometry. In the molecular packing, amide-N–H···S(thione) hydrogen bonds stabilise a supramolecular chain along the a-axis and these are connected into a three-dimensional arrangement by methylene-C–H···O and methylene-C–H···π(pyridyl) interactions. The relative importance of the specified intermolecular interactions and weaker, contributing contacts has been revealed by an analysis of the calculated Hirshfeld surfaces of 1 and 2.

Crystal structure of catena-poly{(μ2-N 1,N 2-bis[(pyridin-4-yl)methyl]ethanediamide-κ2 N:N′)-bis(O,O′-di-isopropyldithiophosphato-κ1 S)zinc(II)} — acetonitrile (1/1), C26H42N4O6P2S4Zn⋅C2H3N

“…Further, the central di-amide group leads to the possibility of forming strong hydrogen bonding interactions to facilitate supramolecular assemblies. In the context of the zinc-triad elements, 4 [8].…”

“…However, when the steric bulk of R was increased to cyclohexyl (Cy), only a binuclear aggregate could be isolated, i.e. [Zn(S 2 COCy) 2 ] 2 ( 4 LH 2 ) [8]. Herein, in continuation of studies in this area, the crystal and molecular structures of a zinc(II) dithiophosphate ( − S 2 P(OR) 2 ) derivative, namely {Zn[S 2 P(O-iPr) 2 ) 2 ] 2 ( 4 LH 2 )}n, (I) is described.…”

Crystal structure of the 1:2 co-crystal between N,N′-bis(4-pyridylmethyl)oxalamide and acetic acid as a dihydrate, C14H14N4O2⋅2 C2H4O2⋅2 H2O

“…The key feature of the molecules in terms of co-crystal formation is the presence of a central di-amide functionality as well as two terminal pyridyl residues, both of which are capable of participating in conventional hydrogen bonding. Continuing interest in examining co-crystal formation of 4 LH 2 and their ability to generate coordination polymers [7][8][9], lead to the isolation of the title 2:1 co-crystal di-hydrate, 4…”

Crystal structure of the co-crystal N,N′-bis(3-pyridylmethyl)oxalamide acetic acid (1/2), C14H14N4O2⋅2C2H4O2

“…A recent review [6] has summarised the structural chemistry of co-crystals, salts and metal complexes functionality is apparent in these molecules, namely in the central di-amide group as well as in the two terminal pyridyl residues. As a part of on-going studies in forming co-crystals and coordination polymers of n LH 2 [7][8][9], the title 2:1 cocrystal, 3 LH 2 •2CH 3 C(=O)OH, was formed and characterised crystallographically. The molecular structures of the molecules comprising the asymmetric unit are shown in the figure (70% displacement ellipsoids).…”