Rhodium–Organic Cuboctahedra as Porous Solids with Strong Binding Sites

Abstract

The upbuilding of dirhodium tetracarboxylate paddlewheels into porous architectures is still challenging because of the inertness of equatorial carboxylates for ligand-exchange reaction. Here we demonstrate the synthesis of a new family of metal-organic cuboctahedra by connecting dirhodium units through 1,3-benzenedicarboxylate and assembling cuboctahedra as porous solids. Carbon monoxide and nitric oxide were strongly trapped in the internal cavity thanks to the strong affinity of unsaturated axial coordination sites of dirhodium centers.

Ultrathin Films of Porous Metal–Organic Polyhedra for Gas Separation

“…MOPsa re nanosized molecules of 2-5nms ynthesised from the self-assembly of metal ions and organic linkers,w hich can be soluble in different polar and nonpolar liquidsa nd are permanently porous in the solid state. [10][11][12][13][14] In this Communication, we showh ow robust Rh II -basedM OPs can be assembled at the air-water interface through the LB technique forming homogenous 2-3 nm thick monolayer films. For this study,w es electedacuboctahedral Rh-MOP functionalized with pendanta liphatic chainsw ith the formula: [Rh 2 (C 12 -bdc) 2 ] 12 (hereafter C 12 RhMOP; C 12 -bdc = 5-dodecyloxybenzene-1,3-dicarboxylate;F igure 1a)d ue to its hydrolytic stability and good solubility in organic solvents, such as dichloromethane (DCM).…”

Stabilizing Metal–Organic Polyhedra (MOP): Issues and Strategies

“…Another strategy to reduce cage rearrangement in the solid state is to use robust paddlewheel units of Rh II and Cr II metal ions to replace their Cu II and Mo II analogues, with the aim of the synthesis of stable carboxylate MOPs. Kitagawa and co‐workers synthesized rhodium‐based metal–organic cuboctahedra formulated as [Rh 2 (bdc) 2 (solv) 2 ] 12 ⋅ (solv); solv=solvent molecules . Owing to the high chemical stability of dirhodium paddlewheel motifs, the resultant Rh II ‐MOPs were endowed with more stability than Cu II analogues.…”

“…Kitagawaa nd coworkers synthesized rhodium-based metal-organic cuboctahedra formulated as [Rh 2 (bdc) 2 (solv) 2 ] 12 ·(solv);solv = solvent molecules. [72] Owing to the high chemical stabilityo fd irhodium paddlewheel motifs, the resultant Rh II -MOPs were endowed with more stabilityt han Cu II analogues.I na ddition to better stability, the Rh II -MOPs recordedb etter gas sorption properties due to the rigid nature of the Rh 2 paddlewheel units. Recently, Furukawa and co-workersd emonstrated synthetic ion channel properties with multiple conductance states in two rhodiumbased MOPs, in whicht he alkoxyg roupsw ere distinct: [Rh 2 (bdc-C 12 ) 2 ] 12 (C 12 RhMOP;b dc-C 12 = 5-dodecyloxy-1,3-benzendicarboxylate) and [Rh 2 (bdc-C 14 ) 2 ] 12 (C 14 RhMOP;b dc-C 14 = 5tetradecyloxy-1,3-benzenedicarboxylate).…”

A Multifunctional, Charge‐Neutral, Chiral Octahedral M12L12 Cage

“…Powder X-ray diffraction (PXRD) after solvent exchange, evacuation and repeated sorption experiments confirms that the crystallinity of the sample remainsl argely unchanged (see Supporting Information). It remains relativelyr are for discrete metal-organic cages to display permanent porosity,w ith retention of crystallinity,w ith recent notable examples including those of Yaghi, [14] Furukawa, [15] Bloch, [16] Zhou, [17] and the nanoballs of Batten. [18] N 2 uptake measurements give aB runauer-Emmett-Teller (BET) surfacea rea of 693 m 2 g À1 .L ow pressure uptake of CO 2 indicates incomplete sorption at the limits of the instrumentation (see Supporting Information), leadingt oh igh pressure experiments being performed to gauge whethert here was a pressure barriert oa ccess the pore space within the cages.…”