1,1′-Fc(4-C₆H₄CO₂Et)₂and its unusual salt derivative withZ′ = 5,catena-[Na⁺]₂[1,1′-Fc(4-C₆H₄CO₂⁻)₂]·0.6H₂O [1,1′-Fc = (η⁵-(C₅H₄)₂Fe]

Abstract

The neutral diethyl 4,4'-(ferrocene-1,1'-diyl)dibenzoate, Fe[eta(5)-(C(5)H(4))(4-C(6)H(4)CO(2)Et)](2) (I), yields (II) (following base hydrolysis) as the unusual complex salt poly[disodium bis[diethyl 4,4'-(ferrocene-1,1'-diyl)dibenzoate] 0.6-hydrate] or [Na(+)](2)[Fe{eta(5)-(C(5)H(4))-4-C(6)H(4)CO(2)(-)}(2)].0.6H(2)O with Z' = 5. Compound (I) crystallizes in the triclinic system, space group P1, with two molecules having similar geometry in the asymmetric unit (Z' = 2). The salt complex (II) crystallizes in the orthorhombic system, space group Pbca, with the asymmetric unit comprising poly[decasodium pentakis[diethyl 4,4'-(ferrocene-1,1'-diyl)dibenzoate] trihydrate] or [Na(+)](10)[Fe{eta(5)-(C(5)H(4))-4-C(6)H(4)CO(2)(-)}(2)](5).3H(2)O. The five independent 1,1'-Fc[(4-C(6)H(4)CO(2))(-)](2) dianions stack in an offset ladder (stepped) arrangement with the ten benzoates mutually oriented cisoid towards and bonded to a central layer comprising the ten Na(+) ions and three water molecules [1,1'-Fc = eta(5)-(C(5)H(4))(2)Fe]. The five dianions differ in the cisoid orientations of their pendant benzoate groups, with four having their -C(6)H(4)- groups mutually oriented at interplanar angles from 0.6 (3) to 3.2 (3) degrees (as pi...pi stacked C(6) rings) and interacting principally with Na(+) ions. The fifth dianion is distorted and opens up to an unprecedented -C(6)H(4)- interplanar angle of 18.6 (3) degrees through bending of the two 4-C(6)H(4)CO(2) groups and with several ionic interactions involving the three water molecules (arranged as one-dimensional zigzag chains in the lattice). Overall packing comprises two-dimensional layers of Na(+) cations coordinated mainly by the carboxylate O atoms, and one-dimensional water chains. The non-polar Fc(C(6)H(4))(2) groups are arranged perpendicular to the layers and mutually interlock through a series of efficient C-H...pi stacking contacts in a herringbone fashion to produce an overall segregation of polar and non-polar entities.

Structure, Conformation and Contact Analyses of Six Aromatic Diamide Diesters

“…In related research, amide ester and amide acid chemistry has also seen the development of a diverse range of ligands, with interesting applications in materials science [7][8][9][10][11][12]. In addition, ferrocenyl(amide)esters and ferrocenyl(benzene)esters and acids have been reported by us as potential organometallic biomaterials [13][14][15][16]. This research is expanded in this study with diamide aromatic ester materials and, as derived from the diesters, their amide benzoic acids.…”

“…This is distinctly separate from the huge area of research involved in planar diimides and related planar systems [31,32]. In wider terms, it can be seen that small molecules can still confound the scientist with both their simplicity and structural complexity, as noted in recent research and publications [5,15,[43][44][45]. In recent reports, the structural scientist continues to be amazed by the increasing complexity of molecular structures as determined by X-ray diffraction [43,44].…”

“…Melting-point data, IR spectroscopy measurements (ATR method; cm −1 ) and NMR spectroscopic methods (CDCl 3 ) for the six DxE and PxE compounds (Scheme 1) are detailed in the ESI (pp. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

“…Melting-point data, IR spectroscopy measure ments (ATR method; cm −1 ) and NMR spectroscopic methods (CDCl3) for the six DxE and PxE compounds (Scheme 1) are detailed in the ESI (pp. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Single-crystal X-ray diffraction methods and data collection procedures for all six DxE and PxE crystal structures (Scheme 1) were routine, with data collected at 100(1) K as reported previously [19,20].…”