Robust, Transformable, and Crystalline Single-Node Organometallic Networks Constructed from Ditopic m-Terphenyl Isocyanides

Abstract

The preparation of 3D and 2D Cu(I) coordination networks using ditopic m-terphenyl isocyanides is described. The incorporation of sterically encumbering substituents enables the controlled, solid-state preparation of Cu(I) tris-isocyanide nodes with a labile solvent ligand in a manner mirroring solution-phase chemistry of monomeric complexes. The protection afforded by the m-terphenyl groups is also shown to engender significant stability towards heat as well as acidic or basic conditions, resulting in robust single-metal-node networks that can transition from 3D to 2D extended structures.

Crystalline Coordination Networks of Zero-Valent Metal Centers: Formation of a 3-Dimensional Ni(0) Framework with m-Terphenyl Diisocyanides

“…Indeed, only a single, anisotropically broadened peak is observed at 2θ = 7.25°, compared with the three peaks predicted from the monoclinic lattice of Ni-ISO CN-2• ([CNAr Mes2 ] 2 ) 0.5 (Figure 3, middle and bottom). Interestingly, this peak position is close to the 220 and 022 reflections of the previously reported valence isoelectronic isocyanide coordination-network Cu-ISO CN-1, 11 which overlap to produce a single observed peak at 2θ = 7.0°in the PXRD pattern (Figure 3, top). Cu-ISO CN-1 adopts a 2-fold interpenetrated diamondoid framework architecture that is identical to Ni-ISO CN-2• ([CNAr Mes2 ] 2 ) 0.5 , but the open void spaces in Cu-ISO CN-1 consequently lead to higher crystal symmetry (Fdd2 vs C2/c).…”

“…However, despite the vast number of low-valent transition metal complexes that have been reported in the literature there are, to our knowledge, no such constructs that have been organized into a well-defined supramolecular network. − This has prevented an analysis of the properties that low-valent species, especially those in zero or negative formal oxidation states, may endow when used as the junction of framework materials. Accordingly, in an extension of our work on coordination frameworks derived from m -terphenyl diisocyanide ligands and four-coordinate Cu­(I) nodes, we now report the formation and physical properties of a valence isoelectronic network material incorporating four-coordinate Ni(0) centers as structural sites.…”

“…This is confirmed by ATR-IR analysis of these crystals showing two bands in the ν(CN) region with peak maxima at 2114 and 1950 cm −1 , the former of which corresponds to free [CNAr Mes2 ] 2 . 11 We contend that the inclusion of free [CNAr Mes2 ] 2 in this structure potentially mitigates framework collapse, and consequently, enables the formation of large single crystals. However, as a result of this feature the crystal symmetry is lowered from the expected high-symmetry for a 2-fold interpenetrated diamondoid net.…”

“…To achieve this, we utilized the recently reported diisocyanide [CNAr Mes2 ] 2 , 11 which is a ditopic dimer of CNAr Mes2 and was shown to be effective in the production of three-and four-coordinate Cu(I) network materials. 12,20,21 In a manner similar to the preparation of Ni(CNAr Mes2 ) 4 , 12,22 we found that the slow addition of 3.0 equiv of [CNAr Mes2 ] 2 to a stirring THF solution of Ni(COD) 2 leads to the precipitation of an amorphous, maroon solid.…”

Long-range anisotropic effects in a V–shaped Tröger's base diformanilide: Conformational study by NMR assignment and DFT calculations

“…This conformational behavior is infrequent in oligoamides, as usually it is not possible to discriminate all the present conformers at room temperature, given that their populations are not similar, their NMR signals are identical or the N-C(O) bond rotation is not slow enough to be in the slow exchange regime [23,[27][28][29][30][31][32][33][34][35][36][37][38]. Chen et al [39] have synthesized a fluorene diformamide derivative whose 1D NMR spectrum in CDCl 3 apparently shows a similar behavior, but it has not been analyzed in detail.…”