Supramolecular Selection in Molecular Alloys

Abstract

Complexes of the type [M(phen)3](PF6)2 (M = Ni(II), Fe(II), Ru(II) and phen = 1,10-phenanthroline) were found to co-crystallize to form molecular alloys (solid solutions of molecules) with general formula [MA x MB 1–x (phen)3](PF6)2·0.5H2O in which the relative concentrations of the metal complexes in the crystals closely match those in the crystallizing solution. Consequently, the composition of the co-crystals can be accurately predicted and controlled by modulating the relative concentrations of the metal complexes in the crystallizing solution. Although they are chemically and structurally similar, complexes of the type [M(bipy)3](PF6)2 (M = Ni(II), Fe(II), Ru(II) and bipy = 2,2′-bipyridine) display markedly different behavior upon co-crystallization. In this case, the resulting co-crystals of general formula [MA x MB 1–x (bipy)3](PF6)2 have relative concentrations of the constituent complexes that are markedly different from the relative concentrations of the complexes initially present in the crystallizing solution. For example, when the nickel and iron complexes are co-crystallized from a solution containing a 50:50 ratio of each, the result is the formation of some crystals with a higher proportion of iron and others with a higher proportion of nickel. The relative concentrations of the metal complexes in the crystals can vary from those in the crystallizing solutions by as much as 15%. This result was observed for a range of combinations of metal complexes (Ni/Fe, Ni/Ru, and Fe/Ru) and a range of starting concentrations in the crystallizing solutions (90:10 through to 10:90 in 10% increments). To explain this remarkable result, we introduce the concept of “supramolecular selection”, which is a process driven by molecular recognition that leads to the partially selective aggregation of like molecules during crystallization.

Tris(1,10-phenanthroline-κ2N,N′)nickel(II) bis(hexafluoridophosphate)

“…The bond lengths and angles in the title complex are very similar to those reported for the hemihydrate form (Brewer et al, 2003;Bouzaid et al, 2012). The asymmetric unit of the title compound is illustrated in Fig.…”

“…Herein, the synthesis and crystal structure of tris(1,10phenanthroline-2 N,N 0 )nickel(II) bis(hexafluoridophosphate) are reported. The crystal structure of the hemihydrate of the title compound has been reported at least twice (Brewer et al, 2003;Bouzaid et al, 2012).…”

Crystal structure of bis(1,10-phenanthroline-κ2N,N′)(1,3-thiazole-2-thiolato-κ2S2,N)nickel(II) hexafluoridophosphate 1,4-dioxane sesquisolvate

“…The narrow bite angle involving the tzS ligand (Table 1) is due to formation of a four-membered chelate ring. The averaged Ni-N(phen) distances and bite angles are 2.08 Å and 80.2 , which are typical values for Ni-phen complexes (Bouzaid et al, 2012).…”

A Trichromatic and White‐Light‐Emitting MOF Composite for Multi‐Dimensional and Multi‐Response Ratiometric Luminescent Sensing

“…Thermogravimetric analyses (TGAs) were carried out on aT A-Q50 thermogravimetric analyzer under N 2 atmosphere with the heating rate of 10 8Cmin À1 .E lemental analyses (C, H, and N) were performed on aV ario EL III elemental analyzer.P owder X-ray diffraction patterns (PXRD) data were collected on D/MAX-2400 X-ray Diffractometer.L uminescence spectra of solid-state samples were acquired at ambient temperature by using aP erkinElmer LS55 fluorescence spectrophotometer.4 -(5,7-dioxo-5,7-dihydroimidazo[4,5-f]isoindol-6(1H)-yl)benzoic acid (H 2 L) was synthesized according to our previously reported method. [19] [Pt(ppy)(NCMe) 2 ]ClO 4 ([Pt]ClO 4 ) [20] and [Ru(bpy) 3 ]( PF 6 ) 2 ([Ru](PF 6 ) 2 ) [21] were synthesized according to the literature methods.…”