MOF matrix isolation: cooperative conformational mobility enables reliable single crystal transformations

Abstract

Obtaining structural information for highly reactive metal-based species can provide valuable insight into important chemical transformations or catalytic processes. Trapping these metal-based species within the cavities of porous crystalline hosts,...

Isolating reactive metal-based species in Metal–Organic Frameworks – viable strategies and opportunities

“…Li In the few cases where SCXRD of metalated UiO-67-bpy materials is possible, successful structural characterisation seems to require distortion of the local structure, lowering symmetry and limiting rotational movement that may give rise to disorder. 128,130,133,140 These features were observed for the rst characterisation of metalated UiO-67-bpy derivatives, 128,130 and are observed in the latest contribution by Long et al 131 In the latter study 131 large metal halide sheets (MX 2 where M ¼ Ni, Co, Fe, and X ¼ Cl and Br) could be isolated and characterised by SCXRD within the pores of UiO-67-bpy. Structure determination shows that the metal halide sheets are effectively excised from the bulk metal halide structure but terminated and stabilised by peripheral bipyridine coordinating groups.…”

Coordination modulated on-off switching of flexibility in a metal–organic framework

“…1 ·[AuCl] was synthesised by metalating 1 with [AuCl(dms)] (dms = dimethylsulfide) in diethyl ether, a solvent known to favour the ‘anti’ conformation at the N , N ′-coordination site. 33 SCXRD analysis revealed a linear AuCl complex coordinated to a single N -donor site in 1 ( Fig. 1 , Fig.…”

“…1•[AuCl] was synthesised by metalating 1 with [AuCl(dms)] (dms= dimethylsulfide) in diethyl ether, a solvent known to favour the 'anti' conformation at the N,N'coordination site. 33 SCXRD analysis revealed a linear AuCl complex coordinated to a single N-donor site in 1 (Figure 1, Figures S15, S16), and EDX analysis of the crystals (Table S2, Figure S17) confirmed the expected Mn:Au:Cl ratio of 3:1: with NaBr or NaI in dry methanol for 24 and 48 hours, respectively. 29,30 In both cases, EDX analysis of the crystals indicated that quantitative halide exchange had occurred (see Mn:Cu:X 3:1:1 ratios; X= Br, I; Table S3, Figure S20).…”

“…[28][29][30][31][32] We have shown that this is primarily due to the intrinsic flexibility of the organic linker which alleviates strain on the framework caused by changes in geometry of the chelated metal ion during reactions. 33 A salient example is cobalt(II) metalated 1 which undergoes a reversible, temperature-dependent, conversion between octahedral 1•[Co(H2O)4]Cl2 and tetrahedral 1•[CoCl2] geometries at the post-synthetic metalation site (Figure 1). 28 These previous observations prompted us to investigate whether coordination chemistry could be exploited as a novel strategy to achieve stimuli-responsive flexibility in 1.…”

“… 28–32 We have shown that this is primarily due to the intrinsic flexibility of the organic linker which alleviates strain on the framework caused by changes in geometry of the chelated metal ion during reactions. 33 A salient example is cobalt( ii ) metalated 1 which undergoes a reversible, temperature-dependent, conversion between octahedral 1 ·[Co(H 2 O) 4 ]Cl 2 and tetrahedral 1 ·[CoCl 2 ] geometries at the post-synthetic metalation site ( Fig. 1 ).…”