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Materials that are isostructural to MIL-101(Cr) were obtained from partial replacement of terephthalic acid to 2-aminoterephthalic acid, a linker containing amine functionalities in the synthesis media. The produced materials were characterized by different techniques, confirming the formation of the structure, their porosity and its functionalization. These results support that our simplified method to insert controllable amounts of amine functionalities on MIL-101(Cr) surface was employed successfully to produce materials that can present different surface character and reactivity.

To develop Rh-catalyzed dehydrocoupling for stereocontrolled synthesis of P−P bonds, we prepared potential intermediates, chiral rhodium phosphine-phosphido complexes, and investigated their stoichiometric and catalytic transformations. Treatment of [Rh(diphos*)(COD)][X] with the bis(secondary phosphine) IsHPCH 2 PHIs (1, Is = 2,4,6-(i-Pr) 3 C 6 H 2 ) gave the cations [Rh(diphos*)(IsHPCH 2 PHIs)][X] (diphos* = (R,R)-Me-DuPhos (2), (R,R)-i-Pr-DuPhos (3), or (R,R)-Me-BPE (4); X = BF 4 or OTf) with high diastereoselectivity as single C 2 -symmetric diastereomers. Deprotonation of 2−4 with NaN(SiMe 3 ) 2 yielded phosphine-phosphido chelates Rh(diphos*)(IsHPCH 2 PIs) 5−7 with high diastereoselectivity. Thermolysis of 5−7 in toluene at 90 °C caused isomerization to give Rh(diphos*)(IsMeP-PIs) (8−10) as mixtures of diastereomers. Under catalytic conditions, Rh-DuPhos precursors slowly converted 1 to a mixture of diastereomers of its isomer, the unsymmetrical diphosphine IsHP-PMeIs ( 12). We propose a possible mechanism for the isomerization and discuss its relationship to dehydrocoupling catalysis.

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The rhodium benzyl complexes Rh­(diphos*)­(η3-CH2Ph) (1–14, diphos* = chiral bis­(phosphine)), potential precursors for asymmetric catalysis, were prepared either by treatment of Rh­(COD)­(η3-CH2Ph) (15, COD = 1,5-cyclooctadiene) with diphos* or from the reaction of [Rh­(diphos*)­(Cl)]2 (16–20) with PhCH2MgCl, and their structures and dynamics were investigated. For C 2-symmetric diphos* (BPE and DuPhos derivatives, Me-FerroLANE, Et-FerroTANE, DIOP, BINAP), observation of one set of NMR signals for complexes 1–12 suggested that the two diastereomers in which different η3-benzyl enantiofaces were coordinated to rhodium interconverted rapidly on the NMR time scale via suprafacial shifts; observation of five inequivalent aryl 1H NMR signals showed that antarafacial shifts were slow on the NMR time scale. With the C 1-symmetric ligands (R,S)-CyPF-t-Bu and (S,R)-Me-BoPhoz, complexes 13 and 14 gave rise to two sets of NMR signals, consistent with fast suprafacial shifts but slow antarafacial shifts on the NMR time scale. Density functional theory studies of the Me-DuPhos, Me-BPE, Ph-BPE, Me-FerroLANE, and CyPF-t-Bu benzyl complexes 1, 4, 7, 11, and 13 showed that enantioface-selective benzyl coordination involved small energy differences (0.4–2.7 kcal/mol). The barrier to interconversion between these isomers by suprafacial shifts was also low (2.2–7.1 kcal/mol), and the computed barrier for antarafacial shifts in Me-DuPhos complex 1 was significantly higher. Treatment of [Rh­(COD)­(Cl)]2 with PhCH2MgCl gave 15; excess Grignard reagent yielded the ate complex [Mg2Cl3(THF)6]­[Rh­(COD)­(η1-CH2Ph)2] (21). Benzyl complexes 11 and 13, 21, and dimers 17–19 (diphos* = (R,R)-i-Pr-DuPhos, (R,R)-Me-FerroLANE, (R,R)-Ph-BPE) were structurally characterized by X-ray crystallography.