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1. Crystallographic characterization of rare-earth cyanotriphenylborate complexes and the cyanoborates [NCBPh ₃ ] ¹⁻ , [NCBPh ₂ Me] ¹⁻ , and [NCBPh ₂ (μ-O)BPh ₂ ] ¹⁻

   https://doi.org/10.1107/S2056989021006861  

   Dumas, Megan T.; White, Jessica R.; Ziller, Joseph W.; Evans, William J. (August 2021, Acta Crystallographica Section E Crystallographic Communications)

   The investigation of the coordination chemistry of rare-earth metal complexes with cyanide ligands led to the isolation and crystallographic characterization of the Ln III cyanotriphenylborate complexes dichlorido(cyanotriphenylborato-κ N )tetrakis(tetrahydrofuran-κ O )lanthanide(III), [ Ln Cl 2 (C 19 H 15 BN)(C 4 H 8 O) 4 ] [lanthanide ( Ln ) = dysprosium (Dy) and yttrium Y)] from reactions of LnCl 3 , KCN, and NaBPh 4 . Attempts to independently synthesize the tetraethylammonium salt of (NCBPh 3 ) − from BPh 3 and [NEt 4 ][CN] in THF yielded crystals of the phenyl-substituted cyclic borate, tetraethylazanium 2,2,4,6-tetraphenyl-1,3,5,2λ 4 ,4,6-trioxatriborinan-2-ide, C 8 H 20 N + ·C 24 H 20 B 3 O 3 − or [NEt 4 ][B 3 (μ-O) 3 (C 6 H 5 ) 4 ]. The mechanochemical reaction of BPh 3 and [NEt 4 ][CN] without solvent produced crystals of tetraethylazanium cyanodiphenyl-λ 4 -boranyl diphenylborinate, C 8 H 20 N + ·C 25 H 20 B 2 NO − or [NEt 4 ][NCBPh 2 (μ-O)BPh 2 ]. Reaction of BPh 3 and KCN in THF in the presence of 2.2.2-cryptand (crypt) led to a crystal of bis[(2.2.2-cryptand)potassium] 2,2,4,6-tetraphenyl-1,3,5,2λ 4 ,4,6-trioxatriborinan-2-ide cyanomethyldiphenylborate tetrahydrofuran disolvate, 2C 18 H 36 KN 2 O 6 + ·C 24 H 20 B 3 O 3 − ·C 14 H 13 BN − ·2C 4 H 8 O or [K(crypt)] 2 [B 3 (μ-O) 3 (C 6 H 5 ) 4 ][NCBPh 2 Me]·2THF. The [NCBPh 2 (μ-O)BPh 2 ] 1− and (NCBPh 2 Me) 1− anions have not been structurally characterized previously. The structure of 1-Y was refined as a two-component twin with occupancy factors 0.513 (1) and 0.487 (1). In 4 , one solvent molecule was disordered and included using multiple components with partial site-occupancy factors. 

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2. Fluoride anion complexation and transport using a stibonium cation stabilized by an intramolecular PO → Sb pnictogen bond

   https://doi.org/10.1039/D1DT03370K  

   Gonzalez, Vanessa M.; Park, Gyeongjin; Yang, Mengxi; Gabbaï, François P. (December 2021, Dalton Transactions)

   We describe the synthesis of [ o -Ph 2 P(O)(C 6 H 4 )SbPh 3 ] + ([2] + ), an intramolecularly base-stabilized stibonium Lewis acid which was obtained by reaction of [ o -Ph 2 P(C 6 H 4 )SbPh 3 ] + with NOBF 4 . This cation reacts with fluoride anions to afford the corresponding fluorostiborane o -Ph 2 P(O)(C 6 H 4 )SbFPh 3 , the structure of which indicates a strengthening of the PO → Sb interaction. When deployed in fluoride-containing POPC unilamellar vesicles, [2] + behaves as a potent fluoride anion transporter whose activity greatly exceeds that of [Ph 4 Sb] + . 

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3. Photodriven Elimination of Chlorine From Germanium and Platinum in a Dinuclear Pt ^II →Ge ^IV Complex

   https://doi.org/10.1002/anie.202107485  

   Karimi, Mohammadjavad; Tabei, Elham S.; Fayad, Remi; Saber, Mohamed R.; Danilov, Evgeny O.; Jones, Cameron; Castellano, Felix N.; Gabbaï, François P. (September 2021, Angewandte Chemie International Edition)

   Abstract Searching for a connection between the two‐electron redox behavior of Group‐14 elements and their possible use as platforms for the photoreductive elimination of chlorine, we have studied the photochemistry of [(o‐(Ph₂P)C₆H₄)₂Ge^IVCl₂]Pt^IICl₂and [(o‐(Ph₂P)C₆H₄)₂ClGe^III]Pt^IIICl₃, two newly isolated isomeric complexes. These studies show that, in the presence of a chlorine trap, both isomers convert cleanly into the platinum germyl complex [(o‐(Ph₂P)C₆H₄)₂ClGe^III]Pt^ICl with quantum yields of 1.7 % and 3.2 % for the Ge^IV–Pt^IIand Ge^III–Pt^IIIisomers, respectively. Conversion of the Ge^IV–Pt^IIisomer into the platinum germyl complex is a rare example of a light‐induced transition‐metal/main‐group‐element bond‐forming process. Finally, transient‐absorption‐spectroscopy studies carried out on the Ge^III–Pt^IIIisomer point to a ligand arene–Cl^.charge‐transfer complex as an intermediate. 

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4. Ligand-enforced intimacy between a gold cation and a carbenium ion: impact on stability and reactivity

   https://doi.org/10.1039/D0SC05777K  

   Litle, Elishua D.; Wilkins, Lewis C.; Gabbaï, François P. (March 2021, Chemical Science)

   null (Ed.)

   Controlling the reactivity of transition metal complexes by positioning non-innocent functionalities around the catalytic pocket is a concept that has led to significant advances in catalysis. Here we describe our efforts toward the synthesis of dicationic phosphine gold complexes of general formula [( o -Ph 2 P(C 6 H 4 )Carb)Au(tht)] 2+ decorated by a carbenium moiety (Carb) positioned in the immediate vicinity of the gold center. While the most acidic examples of such compounds have limited stability, the dicationic complexes with Carb + = 9- N -methylacridinium and Carb + = [C(Ar N ) 2 ] + (Ar N = p -(C 6 H 4 )NMe 2 ) are active as catalysts for the cycloisomerization of N -propargyl-4-fluorobenzamide, a substrate chosen to benchmark reactivity. The dicationic complex [( o -Ph 2 P(C 6 H 4 )C(Ar N ) 2 )Au(tht)] 2+ , which also promotes hydroarylation and enyne cyclization reactions, displays a higher catalytic activity than its acridinium analog, indicating that the electrophilic reactivity of these complexes scales with the Lewis acidity of the carbenium moiety. These results support the role of the carbenium unit as a non-innocent functionality which can readily enhance the activity of the adjacent metal center. Finally, we also describe our efforts toward the generation and isolation of free γ-cationic phosphines of general formula [( o -Ph 2 P(C 6 H 4 )Carb)] + . While cyclization into phosphonium species is observed for Carb + = [C(Ar N ) 2 ] + , [C(Ph)(Ar N )] + , and 9-xanthylium, [( o -Ph 2 P(C 6 H 4 )-9- N -methylacridinium)] + can be isolated as an air stable, biphilic derivative with uncompromised Lewis acidic and basic properties. 

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5. Comparison of two Mn ^IV Mn ^IV -bis-μ-oxo complexes {[Mn ^IV (N ₄ (6-Me-DPEN))] ₂ (μ-O) ₂ } ²⁺ and {[Mn ^IV (N ₄ (6-Me-DPPN))] ₂ (μ-O) ₂ } ²⁺

   https://doi.org/10.1107/S2056989020004557  

   Coggins, Michael K.; Downing, Alexandra N.; Kaminsky, Werner; Kovacs, Julie A. (July 2020, Acta Crystallographica Section E Crystallographic Communications)

   null (Ed.)

   The addition of tert -butyl hydroperoxide ( t BuOOH) to two structurally related Mn II complexes containing N,N -bis(6-methyl-2-pyridylmethyl)ethane-1,2-diamine (6-Me-DPEN) and N,N -bis(6-methyl-2-pyridylmethyl)propane-1,2-diamine (6-Me-DPPN) results in the formation of high-valent bis-oxo complexes, namely di-μ-oxido-bis{[ N , N -bis(6-methyl-2-pyridylmethyl)ethane-1,2-diamine]manganese(II)}( Mn — Mn ) bis(tetraphenylborate) dihydrate, [Mn(C 16 H 22 N 4 ) 2 O 2 ](C 24 H 20 B) 2 ·2H 2 O or {[Mn IV (N 4 (6-Me-DPEN))] 2 ( μ -O) 2 }(2BPh 4 )(2H 2 O) ( 1 ) and di-μ-oxido-bis{[ N , N -bis(6-methyl-2-pyridylmethyl)propane-1,3-diamine]manganese(II)}( Mn — Mn ) bis(tetraphenylborate) diethyl ether disolvate, [Mn(C 17 H 24 N 4 ) 2 O 2 ](C 24 H 20 B) 2 ·2C 4 H 10 O or {[Mn IV (N 4 (6-MeDPPN))] 2 ( μ -O) 2 }(2BPh 4 )(2Et 2 O) ( 2 ). Complexes 1 and 2 both contain the `diamond core' motif found previously in a number of iron, copper, and manganese high-valent bis-oxo compounds. The flexibility in the propyl linker in the ligand scaffold of 2 , as compared to that of the ethyl linker in 1 , results in more elongated Mn—N bonds, as one would expect. The Mn—Mn distances and Mn—O bond lengths support an Mn IV oxidation state assignment for the Mn ions in both 1 and 2 . The angles around the Mn centers are consistent with the local pseudo-octahedral geometry. 

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