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We report intramolecular proton transfer reactions to functionalize carbon monoxide and tert‐butyl nitrile from a bis(phosphido) thorium complex. The reaction of (C5Me5)2Th[PH(Mes)]2, Mes=2,4,6‐Me3C6H2, with 1 atm of CO yields (C5Me5)2Th(κ2‐(O,O)‐OCH2PMes‐C(O)PMes), in which one CO molecule is inserted into each thorium–phosphorus bond. Concomitant transfer of two protons, formerly coordinated to phosphorus, are now bound to one of the carbon atoms from one of the inserted CO molecules. DFT calculations were employed to determine the lowest energy pathway. With tert‐butyl nitrile, tBuCN, only one nitrile inserts into a thorium–phosphorus bond, but the proton is transferred to nitrogen with one phosphido remaining unperturbed affording (C5Me5)2Th[PH(Mes)][κ2‐(P,N)‐N(H)C(CMe3)P(Mes)]. Surprisingly, reaction of this compound with KN(SiMe3)2 removes the proton bound to nitrogen, not phosphorus. [ABSTRACT FROM AUTHOR]

We have re‐examined the reactivity of the manganese dinitrogen complex [Cp(CO)2Mn(N2)] (1, Cp=η5‐cyclopentadienyl, C5H5) with phenylithium (PhLi). By combining experiment and density functional theory (DFT), we have found that, unlike previously reported, the direct nucleophilic attack of the carbanion onto coordinated dinitrogen does not occur. Instead, PhLi reacts with one of the CO ligands to provide an anionic acylcarbonyl dinitrogen metallate [Cp(CO)(N2)MnCOPh]Li (3) that is stable only below −40 °C. Full characterization of 3 (including single crystal X‐ray diffraction) was performed. This complex decomposes quickly above −20 °C with N2 loss to give a phenylate complex [Cp(CO)2MnPh]Li (2). The latter compound was erroneously formulated as an anionic diazenido compound [Cp(CO)2MnN(Ph)=N]Li in earlier reports, ruling out the claimed and so‐far unique behavior of the N2 ligand in 1. DFT calculations were run to explore both the hypothesized and the experimentally verified reactivity of 1 with PhLi and are fully consistent with our results. Direct attack of a nucleophile on metal‐coordinated N2 remains to be demonstrated. [ABSTRACT FROM AUTHOR]

This work reports the synthesis, characterization, and reactivity of the first example of a well‐defined zinc α‐diazoalkyl complex. Treatment of zinc(I)‐zinc(I) bonded compound L2Zn2 [L=CH3C(2,6‐iPr2C6H3N)CHC(CH3)(NCH2CH2PPh2)] or zinc(II) hydride LZnH with trimethylsilyldiazomethane affords zinc diazoalkyl complex LZnC(N2)SiMe3. This complex liberates N2 in the presence of a nickel catalyst to form an α‐zincated phosphorus ylide by reacting with the pendant phosphine. It selectively undergoes formal [3+2] cycloaddition with CO2 or CO to form the corresponding product with a five‐membered heterocyclic core. Notably, the use of CO in such a [3+2] cycloaddition reaction is unprecedented, reflecting a novel CO reaction mode. [ABSTRACT FROM AUTHOR]

Reduction of a range of amido‐ and aryloxy‐aluminum dihydride complexes, e.g. [AlH2(NR3){N(SiMe3)2}] (NR3=NMe3 or N‐methylpiperidine (NMP)), with β‐diketiminato dimagnesium(I) reagents, [{(ArNacnac)Mg}2] (ArNacnac=[HC(MeCNAr)2]−, Ar=mesityl (Mes) or 2,6‐xylyl (Xyl)), have afforded deep red mixed valence aluminum hydride cluster compounds, [Al6H8(NR3)2{Mg(ArNacnac)}4], which have an average Al oxidation state of +0.66, the lowest for any well‐defined aluminum hydride compound. In the solid‐state, the clusters are shown to have distorted octahedral Al6 cores, having zero‐valent Al axial sites and mono‐valent AlH2− equatorial units. Several novel by‐products were isolated from the reactions that gave the clusters, including the Mg−Al bonded magnesio‐aluminate complexes, [(ArNacnac)(Me3N)Mg−Al(μ‐H)3[{Mg(ArNacnac)}2(μ‐H)]]. Computational analyses of one aluminum hydride cluster revealed its Al6 core to be electronically delocalized, and to possess one unoccupied, and six occupied, skeletal molecular orbitals. [ABSTRACT FROM AUTHOR]

The activation of CH bonds has revolutionized modern synthetic chemistry. However, no general strategy for enantiospecific CH activation has been developed to date. We herein report an enantiospecific CH activation reaction followed by deuterium incorporation at stereogenic centers. Mechanistic studies suggest that the selectivity for the α-position of the directing heteroatom results from a four-membered dimetallacycle as the key intermediate. This work paves the way to novel molecular chemistry on nanoparticles. [ABSTRACT FROM AUTHOR]

Hydrogenolysis of alkyl‐substituted cyclopentadienyl (CpR) ligated thorium tribenzyl complexes [(CpR)Th(p‐CH2‐C6H4‐Me)3] (1–6) afforded the first examples of molecular thorium trihydrido complexes [(CpR)Th(μ‐H)3]n (CpR=C5H2(tBu)3 or C5H2(SiMe3)3, n=5; C5Me4SiMe3, n=6; C5Me5, n=7; C5Me4H, n=8; 7–10 and 12) and [(Cp#)12Th13H40] (Cp#=C5H4SiMe3; 13). The nuclearity of the metal hydride clusters depends on the steric profile of the cyclopentadienyl ligands. The hydrogenolysis intermediate, tetra‐nuclear octahydrido thorium dibenzylidene complex [(Cpttt)Th(μ‐H)2]4(μ‐p‐CH‐C6H4‐Me)2 (Cpttt=C5H2(tBu)3) (11) was also isolated. All of the complexes were characterized by NMR spectroscopy and single‐crystal X‐ray analysis. Hydride positions in [(CpMe4)Th(μ‐H)3]8 (CpMe4=C5Me4H) were further precisely confirmed by single‐crystal neutron diffraction. DFT calculations strengthen the experimental assignment of the hydride positions in the complexes 7 to 12. [ABSTRACT FROM AUTHOR]

Enantiopure poly(lactic acid) (PLA) can form stereocomplexes when enantiomeric PLA chains are mixed in equivalent amounts. Such materials provide interesting features that might be suitable for numerous applications. Despite several advantages, the main drawback of PLA is its narrow window of processing, thus limiting its use for industrial applications. Reported herein are achiral iron complexes, that are highly active, productive, and stereoselective under mild reaction conditions for the ring‐opening polymerization of lactide. The corresponding catalytic systems enable the production of stereoblock polymers with high molecular weights, allowing the formation of thermally stable and industrially relevant stereocomplexes. [ABSTRACT FROM AUTHOR]

Abstract: The preferential substitution of oxo ligands over alkyl ones of rare‐earth complexes is commonly considered as “impossible” due to the high oxophilicity of metal centers. Now, it has been shown that simply assembling mixed methyl/oxo rare‐earth complexes to a rigid trinuclear cluster framework cannot only enhance the activity of the Ln‐oxo bond, but also protect the highly reactive Ln‐alkyl bond, thus providing a previously unrecognized opportunity to selectively manipulate the oxo ligand in the presence of numerous reactive functionalities. Such trimetallic cluster has proved to be a suitable platform for developing the unprecedented non‐redox rare‐earth‐mediated oxygen atom transfer from ketones to CS2 and PhNCS. Controlled experiments and computational studies shed light on the driving force for these reactions, emphasizing the importance of the sterical accessibility and multimetallic effect of the cluster framework in promoting reversal of reactivity of rare‐earth oxo complexes. [ABSTRACT FROM AUTHOR]

Die enantiospezifische C ‐ H ‐ Aktivierung mit einem Ruthenium ‐ Nanokatalysator ermöglicht die Deuterium ‐ Markierung von 25 bioaktiven Verbindungen, wie Aminosäuren und Peptiden, mit vollständigem Konfigurationserhalt. In der Zuschrift auf S. 10620 ff. schlagen G. Pieters et al. einen viergliedrigen Dimetallacyclus als Schlüsselintermediat vor und postulieren, dass die kollektive Bewegung von Oberflächenmolekülen die C ‐ H ‐ Aktivierung erleichtert, indem die lokale elektronische Struktur moduliert wird. [ABSTRACT FROM AUTHOR]