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1. HAA by the first {Mn( iii )OH} complex with all O-donor ligands

   https://doi.org/10.1039/d3sc01971c  

   Moore, Shawn M.; Sun, Chen; Steele, Jennifer L.; Laaker, Ellen M.; Rheingold, Arnold L.; Doerrer, Linda H. (July 2023, Chemical Science)

   There is considerable interest in MnOH x moieties, particularly in the stepwise changes in those O–H bonds in tandem with Mn oxidation state changes. The reactivity of aquo-derived ligands, {MOH x }, is also heavily influenced by the electronic character of the other ligands. Despite the prevalence of oxygen coordination in biological systems, preparation of mononuclear Mn complexes of this type with all O-donors is rare. Herein, we report several Mn complexes with perfluoropinacolate (pin F ) 2− including the first example of a crystallographically characterized mononuclear {Mn( iii )OH} with all O-donors, K 2 [Mn(OH)(pin F ) 2 ], 3. Complex 3 is prepared via deprotonation of K[Mn(OH 2 )(pin F ) 2 ], 1, the p K a of which is estimated to be 18.3 ± 0.3. Cyclic voltammetry reveals quasi-reversible redox behavior for both 1 and 3 with an unusually large Δ E p , assigned to the Mn( iii / ii ) couple. Using the Bordwell method, the bond dissociation free energy (BDFE) of the O–H bond in {Mn( ii )–OH 2 } is estimated to be 67–70 kcal mol −1 . Complex 3 abstracts H-atoms from 1,2-diphenylhydrazine, 2,4,6-TTBP, and TEMPOH, the latter of which supports a PCET mechanism. Under basic conditions in air, the synthesis of 1 results in K 2 [Mn(OAc)(pin F ) 2 ], 2, proposed to result from the oxidation of Et 2 O to EtOAc by a reactive Mn species, followed by ester hydrolysis. Complex 3 alone does not react with Et 2 O, but addition of O 2 at low temperature effects the formation of a new chromophore proposed to be a Mn( iv ) species. The related complexes K(18C6)[Mn( iii )(pin F ) 2 ], 4, and (Me 4 N) 2 [Mn( ii )(pin F ) 2 ], 5, have also been prepared and their properties discussed in relation to complexes 1–3. 

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2. Exploring sulfur donor atom coordination chemistry with La( ii ), Nd( ii ), and Tm( ii ) using a terphenylthiolate ligand

   https://doi.org/10.1039/d4cc01037j  

   Gilbert-Bass, Kito; Stennett, Cary R.; Grotjahn, Robin; Ziller, Joseph W.; Furche, Filipp; Evans, William J. (April 2024, Chemical Communications)

   To expand the range of donor atoms known to stabilize 4fⁿ5d¹Ln(ii) ions beyond C, N, and O first row main group donor atoms, the Ln(iii) terphenylthiolate iodides, Ln^III(SAr^iPr6)₂I (Ar^iPr6= C₆H₃-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂, Ln = La, Nd) were reduced to Ln^II(SAr^iPr6)₂complexes. 

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3. Distal Allylic/Benzylic C−H Functionalization of Silyl Ethers Using Donor/Acceptor Rhodium(II) Carbenes

   https://doi.org/10.1002/anie.201916530  

   Vaitla, Janakiram; Boni, Yannick_T; Davies, Huw_M_L (March 2020, Angewandte Chemie International Edition)

   Abstract Regio‐ and stereoselective distal allylic/benzylic C−H functionalization of allyl and benzyl silyl ethers was achieved using rhodium(II) carbenes derived from N‐sulfonyltriazoles and aryldiazoacetates as carbene precursors. The bulky rhodium carbenes led to highly site‐selective functionalization of less activated allylic and benzylic C−H bonds even in the presence of electronically preferred C−H bonds located α to oxygen. The dirhodium catalyst Rh₂(S‐NTTL)₄is the most effective chiral catalyst for triazole‐derived carbene transformations, whereas Rh₂(S‐TPPTTL)₄works best for carbenes derived from aryldiazoacetates. The reactions afford a variety of δ‐functionalized allyl silyl ethers with high diastereo‐ and enantioselectivity. The utility of the present method was demonstrated by its application to the synthesis of a 3,4‐disubstitutedl‐proline scaffold. 

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4. Strain‐Induced Nucleophilic Ring Opening of Donor–Acceptor Cyclopropenes for Synthesis of Monosubstituted Succinic Acid Derivatives

   https://doi.org/10.1002/chem.202003427  

   Marichev, Kostiantyn_O; Wang, Kan; Greco, Nicole; Dong, Kuiyong; Chen, Jinzhou; Lei, Jinping; Doyle, Michael_P (November 2020, Chemistry – A European Journal)

   Abstract 1,2,3‐Trisubstituted donor–acceptor cyclopropenes (DACPs) generated in situ from enoldiazo compounds react with nucleophiles to form α‐substituted succinic acid derivatives in high yields. Initial dirhodium(II) carboxylate catalysis rapidly converts enoldiazo‐acetates or ‐acetamides to DACPs that undergo catalyst‐free Favorskii ring opening with amines, and also with anilines, alcohols, and thiols, when facilitated by catalytic amounts of 4‐dimethylaminopyridine (DMAP). This methodology provides easy access to mixed esters and amides of monosubstituted succinic acids, including derivatives of naturally occurring compounds. It also affords dihydrazide, dihydroxamic acid, and diamide derivatives, as well as α‐substituted tetrahydropyridazine‐3,6‐diones in high yields. Attempts to generate optically enriched DACPs were not successful because their populations having theRandSconfigurations formed with a chiral dirhodium catalyst are quite similar, and the loss of enantiocontrol likely originates from the DACP ring forming step which is reversible with its intermediate metal carbene. 

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5. Electrically Conductive π‐Intercalated Graphitic Metal‐Organic Framework Containing Alternate π‐Donor/Acceptor Stacks

   https://doi.org/10.1002/anie.202303819  

   Yadav, Ashok; Zhang, Shiyu; Benavides, Paola A.; Zhou, Wei; Saha, Sourav (April 2023, Angewandte Chemie International Edition)

   Abstract Two‐dimensional graphitic metal–organic frameworks (GMOF) often display impressive electrical conductivity chiefly due to efficient through‐bond in‐plane charge transport, however, less efficient out‐of‐plane conduction across the stacked layers creates large disparity between two orthogonal conduction pathways and dampens their bulk conductivity. To address this issue and engineer higher bulk conductivity in 2D GMOFs, we have constructed via an elegant bottom‐up method the first π‐intercalated GMOF (iGMOF1) featuring built‐in alternate π‐donor/acceptor (π‐D/A) stacks of Cu^II‐coordinated electron‐rich hexaaminotriphenylene (HATP) ligands and non‐coordinatively intercalated π‐acidic hexacyano‐triphenylene (HCTP) molecules, which facilitated out‐of‐plane charge transport while the hexagonal Cu₃(HATP)₂scaffold maintained in‐plane conduction. As a result, iGMOF1 attained an order of magnitude higher bulk electrical conductivity and much smaller activation energy than Cu₃(HATP)₂(σ=25 vs. 2 S m⁻¹,E_a=36 vs. 65 meV), demostrating that simultaneous in‐plane (through‐bond) and out‐of‐plane (through πD/A stacks) charge transport can generate higher electrical conductivity in novel iGMOFs. 

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