A Remarkable Organometallic Transformation on a Cage‐Incarcerated Dinuclear Ruthenium Complex

Horiuchi, Shigeo; Murase, Takashi; Fujita, Makoto

doi:10.1002/anie.201206325

Cited by 62 publications

(34 citation statements)

References 36 publications

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“…[18] Non-hydrogen atoms were refined with anisotropic displacement coefficients. Due to the presence of highly disordered solvents, refinements of all complexes (CoL,1a,2a,2b,3a,and 3b)were carried out with constraints on afew bond distances, fixed using the DFIX command, and final refinements were performed with the modification of the structure factors for the electron densities of the solvent molecules using the SQUEEZE option of PLATON. Due to the presence of highly disordered solvents, refinements of all complexes (CoL,1a,2a,2b,3a,and 3b)were carried out with constraints on afew bond distances, fixed using the DFIX command, and final refinements were performed with the modification of the structure factors for the electron densities of the solvent molecules using the SQUEEZE option of PLATON.…”

Section: X-ray Crystallographic Studymentioning

confidence: 99%

Stepwise Construction of Self‐Assembled Heterometallic Cages Showing High Proton Conductivity

Saha

Samanta

Bhattacharyya

et al. 2017

Chemistry A European J

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Two neutral tripodal metalloligands (CoL and FeL where L=C H N ) containing a clathrochelate core were synthesized and characterized in one-step. Reactions of these ligands with three different metal acceptors cis-(tmen)Pd(NO ) (tmen = tetramethylethylenediamine), Zn(NO ) and Mn(ClO ) separately yielded a series of heterometallic coordination cages (1 a-3 a and 1 b-3 b) in high yields. Depending on the nature of coordination geometry of the acceptors, the resulting assemblies have trigonal- bipyramidal (1 a/1 b), open-cubic (2 a/2 b), and closed-cubic structures (3 a/3 b). The structures of the complexes 1 a, 2 a, 2 b, 3 a, and 3 b were confirmed by single-crystal X-ray diffraction studies. Analysis of crystal packing of the complexes 3 a and 3 b revealed the presence of several coordinated and lattice water molecules in the intermolecular channels. Both these complexes (3 a and 3 b) showed very high water adsorption under humid conditions. In addition, 3 a and 3 b exhibited promising proton conductivity of 3.31×10 and 1.05×10 S cm at 70 °C under 98 % relative humidity (RH) respectively, with activation energy of 1.00-0.78 eV.

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Section: X-ray Crystallographic Studymentioning

confidence: 99%

Stepwise Construction of Self‐Assembled Heterometallic Cages Showing High Proton Conductivity

Saha

Samanta

Bhattacharyya

et al. 2017

Chemistry A European J

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“…Typically, cations are used to attract heteroatoms to bring the substrate's ends together, as in Pedersen's (19) synthesis of crown ethers or Dietrich-Buchecker et al's synthesis of catenanes (20). In the related closed-shell capsules, the shape of the space inside can guide guests along congruent reaction pathways (21)(22)(23)(24)). The open-ended cavitands here leave the polar end groups exposed to reagents in the aqueous medium where their chemical reactions take place.…”

Section: Resultsmentioning

confidence: 99%

Water-soluble cavitands promote hydrolyses of long-chain diesters

Shi

Mower

Blackmond

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Water-soluble, deep cavitands serve as chaperones of long-chain diesters for their selective hydrolysis in aqueous solution. The cavitands bind the diesters in rapidly exchanging, folded J-shape conformations that bury the hydrocarbon chain and expose each ester group in turn to the aqueous medium. The acid hydrolyses in the presence of the cavitand result in enhanced yields of monoacid monoester products. Product distributions indicate a two-to fourfold relative decrease in the hydrolysis rate constant of the second ester caused by the confined space in the cavitand. The rate constant for the first acid hydrolysis step is enhanced approximately 10-fold in the presence of the cavitand, compared with control reactions of the molecules in bulk solution. Hydrolysis under basic conditions (saponification) with the cavitand gave >90% yields of the corresponding monoesters. Under basic conditions the cavitand complex of the monoanion precipitates from solution and prevents further reaction.M onofunctionalization of symmetrical compounds poses a general problem: When identical functional groups on a substrate are truly remote, they act independently, and reactions result in a statistical mixture of products. For example, hydrolysis of diesters ( Fig. 1) separated by a long methylene chain exhibits equal rate constants at each site (k 1 = k 2 ), which sets an upper limit of 36.8% for the yield of the monoester. This maximum occurs when comparable amounts of unreacted diester and doubly reacted diacid product are present ( Fig. 1), a factor that often complicates isolation of the desired monoester product.Special circumstances can favor monofunctionalization. When the monofunctionalized compound has fortuitously different properties (such as solubility) and can be removed to a different phase (1) as it is formed, good yields can result. Likewise, when the sites are not remote--as in diesters of oxalic acid--reaction at one site greatly modifies reactivity at the other site and affects the yield of the monofunctionalized product. We describe here the application of synthetic container compounds (cavitands) as molecular chaperones to address the monofunctionalization problem. Whereas the present examples involve only hydrolysis of long-chain diesters, the predictable influence of the cavitand promises wider applications in other reactions of symmetrical, difunctional substrates. Results and DiscussionWe recently reported the synthesis of deep cavitand 1 (Fig. 2) and its capacity to sequester hydrophobic and amphiphilic species in water (2). The eight methyl groups of cavitand 1 broaden its upper rim and prevent dimerization through hydrogen bonding into a capsule. The cavitand is stable over a wide pH range. Whereas a number of water-soluble, deep cavitand hosts are available (3-10), cavitand 1 bound long-chain guest alkanes and related difunctional compounds (bola-amphiphiles) in folded conformations (11). Folded alkyls inside a γ-cyclodextrin were initially characterized by Turro et al. (12), and folded bola-amphiphiles ...

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“…Photo-labile Ru 2 dinuclear complex [(indenyl)Ru(CO) 2 ] 2 gains photo-stability through encapsulation in cationic coordination cage 2. [(Me 4 Cp)Ru(CO) 2 ] 2 (Cp = cyclopentadienyl) in cage 2 undergo photo-substitution of a CO ligand with alkyne (4-octyne) to form a Ru-alkyne π-complex without metal-metal bond cleavage [145]. The trapped metastable ruthenium π-complex inside the cavity gets converted to a diruthenacyclopentenone framework by intramolecular CO insertion as attributed by A c c e p t e d M a n u s c r i p t reduction in cage symmetry from T d to C 2v ( fig.…”

Section: Catalysismentioning

confidence: 99%

“…Reproduced with permission from[145].Photo-catalytic production of H 2 from H 2 O is one of the biggest challenges for future. The structure exposition of [FeFe]-H 2 ases gives a chance to reduce H 2 O into H 2 in an excited state[146,147].…”

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confidence: 99%