A Simple Approach to Coordination Compounds of the Pentacyanocyclopentadienide Anion

Abstract

Deprotonation of [Et(3)NH][C(5)(CN)(5)] with metal bases provides a very simple approach to coordination compounds containing the pentacyanocyclopentadienide anion [C(5)(CN)(5)](-) (1). The three-dimensional polymer [Na(thf)(1.5)(1)](∞) and the molecular dimer [{(tmeda)(2)Na(1)}(2)] are obtained by reaction of this precursor with NaH in the presence of thf or tmeda (Me(2)NCH(2)CH(2)NMe(2)). Their single-crystal X-ray structures both reveal σ-bonded C≡N-Na arrangements and π stacking between [C(5)(CN)(5)](-) ions. DFT calculations on the [C(5)(CN)(5)](-) ion have been used to investigate the structures and bonding in [Na(thf)(1.5)(1)](∞) and [{(tmeda)(2)Na(1)}(2)]. The absence of π bonding of the metal ions in both complexes is due to dispersion of the negative charge from the C(5) ring unit to the C[triple chemical bond]N groups in the [C(5)(CN)(5)](-) ion, making the coordination chemistry of this anion distinctly different from that of cyclopentadienide C(5)H(5)(-).

First decade of π-electronic ion-pairing assemblies

“…36 Cations with bulky geometries afforded chargesegregated assemblies. For example, the ion pairs of PCCp − with a triethylammonium cation by Wood and Wright et al 37 and with butyltrimethylammonium (C 4 H 9 IJCH 3 ) 3 N + ) and TPA + provided charge-segregated assemblies based on the stacking columnar structures of PCCp − in the crystal state (Fig. 15b).…”

The Tetracyanopyrrolide Anion as Ligand in Transition Metal Complexes

“…The complexes [Co(MeCN) 4 (2) show that the tetracyanopyrrolide anion acts as a monodentate ligand towards transition metal ions. Only the η 1 -N-σ coordination mode via the lone electron pair of the nitrogen atom of the pyrrole ring was found.…”

“…Magnetic susceptibility data of [Ni(MeCN) 4 (tcp) 2 ]·2MeCN (2) and, due to its sensitivity [Co(MeCN) 4 (tcp) 2 ]·2MeCN (1) with some loss of incorporated MeCN were recorded in the range of 1.9-300 K. Both complexes show nearly ideal Curie behavior in the full temperature range and therefore display regular paramagnetism. From the equation μ eff = 2.828(χ mol T) 1/2 the calculated effective magnetic moment per Ni 2+ ion in complex 2 at 300 K is 3.09 μ B , which fits well with the free Ni 2+ ion spin-only value for a S = 1 system (μ eff = 2.83 μ B ) (see Supporting Information).…”

Ion‐Pairing Assemblies Based on Pentacyano‐Substituted Cyclopentadienide as a π‐Electronic Anion

“…Due to the introductiono fs trongly electron-withdrawing moieties,p entacyano-substituted Cp À (PCCp À ;F igure 2a) [10] is one of the most stable Cp À ions, producing ac harge-segregated assemblyw ith the triethylammonium cation( Et 3 NH + )i nt he solid state. [11] We therefore focusedo nP CCp À as an effective buildingu nit for ion-pairing assemblies in combination with variousc ations (Figure 2b and c) for the formationo favariety of dimension-controlled assemblies, which include aggregates in solution,1 Da nd 2D crystals,s upramolecular gels, and liquid crystals. Diverse ion-pairing assembliesb ased on PCCp À in both the solid state and dimension-controlled states are fabricated with contributionsf rom charge-by-charge and chargesegregated modes, depending on the cationic species.…”