We introduce the heterocumulene ligand [(Ad)NCC(
This content will become publicly available on February 21, 2025
Reaction of [CuH(PPh3)]6with 1 equiv. of Tl(OTf) results in formation of [Cu6TlH6(PPh3)6][OTf] (
- NSF-PAR ID:
- 10495250
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- ISSN:
- 0947-6539
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract t Bu)]−(Ad=1‐adamantyl (C10H15),t Bu=tert ‐butyl, (C4H9)), which can adopt two forms, the azaalleneyl and ynamide. This ligand platform can undergo a reversible chelotropic shift using Brønsted acid‐base chemistry, which promotes an unprecedented spin‐state change of the [VIII] ion. These unique scaffolds are prepared via addition of 1‐adamantyl isonitrile (C≡NAd) across the alkylidyne in complexes [(BDI)V≡Ct Bu(OTf)] (A ) (BDI−=ArNC(CH3)CHC(CH3)NAr), Ar=2,6‐i Pr2C6H3) and [(dBDI)V≡Ct Bu(OEt2)] (B ) (dBDI2−=ArNC(CH3)CHC(CH2)NAr). ComplexA reacts with C≡NAd, to generate the high‐spin [VIII] complex with a κ1‐N ‐ynamide ligand, [(BDI)V{κ1‐N ‐(Ad)NCC(t Bu)}(OTf)] (1 ). Conversely,B reacts with C≡NAd to generate a low‐spin [VIII] diamagnetic complex having a chelated κ2‐C ,N ‐azaalleneyl ligand, [(dBDI)V{κ2‐N ,C ‐(Ad)NCC(t Bu)}] (2 ). Theoretical studies have been applied to better understand the mechanism of formation of2 and the electronic reconfiguration upon structural rearrangement by the alteration of ligand denticity between1 and2 . -
more » « less
Abstract A remarkable distinction between boron and carbon hydrides lies in their extremely different bonding patterns and chemical reactivity, resulting in diverse areas of application. Particularly, carbon, characterized by classical two‐center – two‐electron bonds, gives rise to organic chemistry. In contrast, boron forms numerous exotic and non‐intuitive compounds collectively called non‐classical structures. It is reasonable to anticipate that other elements of Group 13 exhibit their own unusual bonding patterns; however, our knowledge of the hydride chemistry for other elements in Group 13 is much more limited, especially for the heaviest stable element, thallium. In this work, we performed a conformational analysis of Tl2Hxand Tl3Hy(x=0–6, y=0–5) series via Coalescence Kick global minimum search algorithm, DFT, and
ab initio quantum chemistry methods; we investigated the bonding pattern using the AdNDP algorithm, thermodynamic stability, and stability toward electron detachment. All found global minimum structures are classified as non‐classical structures featuring at least one multi‐center bond. -
more » « less
Abstract A new series of mono‐ and bis‐alkynyl CoIII(TIM) complexes (TIM=2,3,9,10‐tetramethyl‐1,4,8,11‐tetraazacyclotetradeca‐1,3,8,10‐tetraene) is reported herein. The
trans ‐[Co(TIM)(C2R)Cl]+complexes were prepared from the reaction betweentrans ‐[Co(TIM)Cl2]PF6and HC2R (R=tri(isopropyl)silyl or TIPS (1 ), ‐C6H4‐4‐tBu (2 ), ‐C6H4‐4‐NO2(3 a ), andN ‐mesityl‐1,8‐naphthalimide or NAPMes(4 a )) in the presence of Et3N. The intermediate complexes of the typetrans ‐[Co(TIM)(C2R)(NCMe)](PF6)(OTf),3 b and4 b , were obtained by treating3 a and4 a , respectively, with AgOTf in CH3CN. Furthermore, bis‐alkynyltrans ‐[Co(TIM)(C2R)2]PF6complexes,3 c and4 c , were generated following a second dehydrohalogenation reaction between3 b and4 b , respectively, and the appropriate HC2R in the presence of Et3N. These new complexes have been characterized using X‐ray diffraction (2 ,3 a ,4 a , and4 c ), IR,1H NMR, UV/Vis spectroscopy, fluorescent spectroscopy (4 c ), and cyclic voltammetry. -
more » « less
Abstract The dialkyl malonate derived 1,3‐diphosphines R2C(CH2PPh2)2(R=
a , Me;b , Et;c ,n ‐Bu;d ,n ‐Dec;e , Bn;f ,p ‐tolCH2) are combined with (p ‐tol3P)2PtCl2ortrans ‐(p‐ tol3P)2Pt((C≡C)2H)2to give the chelatescis ‐(R2C(CH2PPh2)2)PtCl2(2 a –f , 94–69 %) orcis ‐(R2C(CH2PPh2)2)Pt((C≡C)2H)2(3 a –f , 97–54 %). Complexes3 a –d are also available from2 a –d and excess 1,3‐butadiyne in the presence of CuI (cat.) and excess HNEt2(87–65 %). Under similar conditions,2 and3 react to give the title compounds [(R2C(CH2PPh2)2)[Pt(C≡C)2]4(4 a –f ; 89–14 % (64 % avg)), from which ammonium salts such as the co‐product [H2NEt2]+Cl−are challenging to remove. Crystal structures of4 a ,b show skew rhombus as opposed to square Pt4geometries. The NMR and IR properties of4 a –f are similar to those of mono‐ or diplatinum model compounds. However, cyclic voltammetry gives only irreversible oxidations. As compared to mono‐platinum or Pt(C≡C)2Pt species, the UV‐visible spectra show much more intense and red‐shifted bands. Time dependent DFT calculations define the transitions and principal orbitals involved. Electrostatic potential surface maps reveal strongly negative Pt4C16cores that likely facilitate ammonium cation binding. Analogous electronic properties of Pt3C12and Pt5C20homologs and selected equilibria are explored computationally. -
more » « less
Abstract A low‐spin and mononuclear vanadium complex, (Menacnac)V(CO)(η2‐P≡C
t Bu) (2 ) (Menacnac−=[ArNC(CH3)]2CH, Ar=2,6‐i Pr2C6H3), was prepared upon treatment of the vanadium neopentylidyne complex (Menacnac)V≡Ct Bu(OTf) (1 ) with Na(OCP)(diox)2.5(diox=1,4‐dioxane), while the isoelectronic ate‐complex [Na(15‐crown‐5)]{([ArNC(CH2)]CH[C(CH3)NAr])V(CO)(η2‐P≡Ct Bu)} (4 ), was obtained via the reaction of Na(OCP)(diox)2.5and ([ArNC(CH2)]CH[C(CH3)NAr])V≡Ct Bu(OEt2) (3 ) in the presence of crown‐ether. Computational studies suggest that the P‐atom transfer proceeds by [2+2]‐cycloaddition of the P≡C bond across the V≡Ct Bu moiety, followed by a reductive decarbonylation to form the V−C≡O linkage. The nature of the electronic ground state in diamagnetic complexes,2 and4 , was further investigated both theoretically and experimentally, using a combination of density functional theory (DFT) calculations, UV/Vis and NMR spectroscopies, cyclic voltammetry, X‐ray absorption spectroscopy (XAS) measurements, and comparison of salient bond metrics derived from X‐ray single‐crystal structural characterization. In combination, these data are consistent with a low‐valent vanadium ion in complexes2 and4 . This study represents the first example of a metathesis reaction between the P‐atom of [PCO]−and an alkylidyne ligand.
