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A low‐valent GaI complex with the superbulky β‐diketiminate ligand DIPePBDI (HC[C(Me)N−DIPeP]2, DIPeP=2,6‐C(H)Et2‐phenyl)) was obtained by reduction of (DIPePBDI)GaI2 (1) with KC8 in toluene. Considering that (BDI)GaI and analogue (BDI)AlI complexes are prone to decomposition and can generally only be obtained in low yields (20–40 %), the quantitative formation of (DIPePBDI)GaI (2) is remarkable and no doubt related to its excellent thermal stability even in refluxing toluene. Although the low‐valent metal center in 2 is sterically protected by the superbulky DIPePBDI ligand, it is readily oxidized by N2O to give intermediate (DIPePBDI)Ga=O which readily decomposed by abstracting a proton from the backbone Me‐substituent. Reaction with trimethylsilyl azide gave an intermediate imido complex (DIPePBDI)Ga=N(SiMe3)2 which reacted with a second equivalent of Me3SiN3 to a mixture of an azide/amido complex (DIPePBDI)GaN3[N(SiMe3)2] (4) and a tetrazagallole complex (DIPePBDI)Ga[N4(SiMe3)2] (5) in a 1 : 2 ratio. Whereas the azide/amido complex 4 could be structurally characterised, the tetraazagallole complex 5 was identified by NMR spectroscopy. DFT calculations on (DIPePBDI)GaI (2) and its reaction products complement this study. [ABSTRACT FROM AUTHOR]

The new hydrazine 5H-dibenzo[b,f]azepin-5-amine (2) reacts with P- and Si-electrophiles via deprotonation to afford P(III)-, P(V)-, and TMS-hydrazides 3–8 and with carbonyl electrophiles via acid-free condensation to the N-substituted hydrazones 9–12 that are potential N-alkene ligands. While β-ketohydrazone 9 and α-dihydrazone 10 react with [Mes(Cu)]4, [Cu(NCCCH3)4]2PF6, and FeCl2(THF)1.5 to afford complexes devoid of alkene interaction, [Cu(OTf)]2·C6H6 reacts with the α-keto hydrazone 11 or with N,N dimethyl-hydrazone 12 to form the neutral dimeric Cu(I) complex 18 with bridging Cu(I)–alkene interactions or the tetrahedral cationic complex 19 in which 12 binds as a bidentate hydrazone-alkene ligand, respectively. The surprising stability of the alkene coordination in complexes 18 and 19 prevents substitutions with, e.g., PPh3. [ABSTRACT FROM AUTHOR]

Monoanionic N,N‐chelating triazenide ligands, [R‐NNN‐R]−, are compared to formamidinate or β‐diketiminate ligands considerably less electron‐donating and therefore potentially suitable for stabilizing electron rich metals in low oxidations states. A feature reported for silyl‐substituted triazenide ligands, is their ability to eliminate N2 resulting in (R3Si)2N− anions. Here we describe a series of group 1 and 2 metal complexes with the very bulky bis‐silyl‐triazenide ligand [tBu3Si‐NNN‐SitBu3]−. Heteroleptic complexes could be isolated for Mg: {[(tBu3Si)2N3]MgnBu}2 or {[(tBu3Si)2N3]MgI}2, including its ether adducts. Despite bulky silyl substituents, the ligand did not stabilize heteroleptic [(tBu3Si)2N3]AeN(SiMe3)2 complexes for Ca, Sr and Ba and only homoleptic Ae[(tBu3Si)2N3]2 complexes were isolated. Thermal decomposition of these complexes did result in N2 elimination and formation of the expected amide complexes. Reduction of [(tBu3Si)2N3]MgI ⋅ (Et2O) with KC8 in Et2O led to the formation of a MgI complex with a Mg−Mg bond length of 2.902(1) Å. As only one of the Mg centres shows coordination with a Et2O ligand, this is a rare example of an asymmetric Mg−Mg bond. This MgI complex is rather unstable in benzene solution, likely due to reduction of the ligand system. Triazenide ligands are therefore not suitable for stabilization of group 2 metals in low oxidation states. [ABSTRACT FROM AUTHOR]

Alkene planar chirality is introduced in the 'privileged' P-alkene phosphoramidite ligand 1. The resulting diastereomeric ligands (pR,R)-5 and (pS,R)-5 form optically pure complexes of Rh(I) and Pd(II), which catalyze conjugate additions of boron C-nucleophiles to enones and allylic alkylations, respectively. In the Rh-catalyzed reaction, the planar chirality of the alkene exerts absolute enantiocontrol over the potent BINOL auxiliary. [ABSTRACT FROM AUTHOR]

Cu(I)-Hydrido complexes supported by dibenzo[b,f]azepinyl P-alkene hybrid ligands and stabilized by electrostatic interactions in a Cu–H⋯KCl⋯BR3 arrangement can be trapped with CO2 at low temperature to afford Cu(I)-formates. The complexes are isolable with and without a pendant BEt3 group and show strong Cu–O and weak B–O interactions. [ABSTRACT FROM AUTHOR]

Low‐valent MgI complexes like (BDI)Mg−Mg(BDI) have found wide‐spread application as specialty reducing agents (BDI=β‐diketiminate). Also their redox reactivity was extensively investigated. In contrast, attempts to isolate similar CaI complexes led to reduction of the aromatic solvents or N2. Complex (DIPePBDI)Ca(μ6,μ6‐C6H6)Ca(DIPePBDI) (VIII) should be regarded a CaII complex with a bridging C6H62− dianion (DIPePBDI=HC[C(Me)N‐DIPeP]2, DIPeP=2,6‐C(H)Et2‐phenyl). It can react as a CaI synthon by releasing benzene and two electrons. Herein we describe the reactivity of VIII with benzene, biphenyl, naphthalene, anthracene, COT, Ph3SiCl, PhSiH3, a (BDI)AlI2 complex, H2, PhX (X=F, Cl, Br, I), tBuOH and tBuCH2I. The C6H62− dianion in VIII can react as a 2e− source, a nucleophile or a Brønsted base. In some cases radical reactivity cannot be excluded. Crystal structures of (DIPePBDI)Ca(μ8,μ8‐COT)Ca(DIPePBDI) (1) and [(DIPePBDI)CaX ⋅ (THF)]2 (X=F, Cl, Br, I) (2–5) are described. [ABSTRACT FROM AUTHOR]

Complex [(DIPePBDI)Ca]2(C6H6), with a C6H62− dianion bridging two Ca2+ ions, reacts with benzene to yield [(DIPePBDI)Ca]2(biphenyl) with a bridging biphenyl2− dianion (DIPePBDI=HC[C(Me)N‐DIPeP]2; DIPeP=2,6‐CH(Et)2‐phenyl). The biphenyl complex was also prepared by reacting [(DIPePBDI)Ca]2(C6H6) with biphenyl or by reduction of [(DIPePBDI)CaI]2 with KC8 in presence of biphenyl. Benzene‐benzene coupling was also observed when the deep purple product of ball‐milling [(DIPPBDI)CaI(THF)]2 with K/KI was extracted with benzene (DIPP=2,6‐CH(Me)2‐phenyl) giving crystalline [(DIPPBDI)Ca(THF)]2(biphenyl) (52 % yield). Reduction of [(DIPePBDI)SrI]2 with KC8 gave highly labile [(DIPePBDI)Sr]2(C6H6) as a black powder (61 % yield) which reacts rapidly and selectively with benzene to [(DIPePBDI)Sr]2(biphenyl). DFT calculations show that the most likely route for biphenyl formation is a pathway in which the C6H62− dianion attacks neutral benzene. This is facilitated by metal‐benzene coordination. [ABSTRACT FROM AUTHOR]

The preparation of the alkaline earth metal bis(diphenylamides) which are potentially useful as polymerization initiators, through metathesis and metalation reactions, depending on the metal is presented.