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Three distinct routes are reported to the soluble, dihydridoaluminate compounds, AM[Al(NONDipp)(H)2] (AM=Li, Na, K, Rb, Cs; [NONDipp]2−=[O(SiMe2NDipp)2]2−; Dipp=2,6‐iPr2C6H3) starting from the alkali metal aluminyls, AM[Al(NONDipp)]. Direct H2 hydrogenation of the heavier analogues (AM=Rb, Cs) produced the first examples of structurally characterized rubidium and caesium dihydridoaluminates, although harsh conditions were required for complete conversion. Using 1,4‐cyclohexadiene (1,4‐CHD) as an alternative hydrogen source in transfer hydrogenation reactions provided a lower energy pathway to the full series of products for AM=Li−Cs. A further moderation in conditions was noted for the thermal decomposition of the (silyl)(hydrido)aluminates, AM[Al(NONDipp)(H)(SiH2Ph)]. Probing the reaction of Cs[Al(NONDipp)] with 1,4‐CHD provided access to a novel inverse sandwich complex, [{Cs(Et2O)}2{Al(NONDipp)(H)}2(C6H6)], containing the 1,4‐dialuminated [C6H6]2− dianion and representing the first time that an intermediate in the commonly utilized oxidation process of 1,4‐CHD to benzene has been trapped. The synthetic utility of the newly installed Al−H bonds has been demonstrated by their ability to reduce CO2 under mild conditions to form the bis‐formate AM[Al(NONDipp)(O2CH)2] compounds, which exhibit a diverse series of eyecatching bimetallacyclic structures. [ABSTRACT FROM AUTHOR]

Three distinct routes are reported to the soluble, dihydridoaluminate compounds, AM[Al(NONDipp)(H)2] (AM=Li, Na, K, Rb, Cs; [NONDipp]2−=[O(SiMe2NDipp)2]2−; Dipp=2,6‐iPr2C6H3) starting from the alkali metal aluminyls, AM[Al(NONDipp)]. Direct H2 hydrogenation of the heavier analogues (AM=Rb, Cs) produced the first examples of structurally characterized rubidium and caesium dihydridoaluminates, although harsh conditions were required for complete conversion. Using 1,4‐cyclohexadiene (1,4‐CHD) as an alternative hydrogen source in transfer hydrogenation reactions provided a lower energy pathway to the full series of products for AM=Li−Cs. A further moderation in conditions was noted for the thermal decomposition of the (silyl)(hydrido)aluminates, AM[Al(NONDipp)(H)(SiH2Ph)]. Probing the reaction of Cs[Al(NONDipp)] with 1,4‐CHD provided access to a novel inverse sandwich complex, [{Cs(Et2O)}2{Al(NONDipp)(H)}2(C6H6)], containing the 1,4‐dialuminated [C6H6]2− dianion and representing the first time that an intermediate in the commonly utilized oxidation process of 1,4‐CHD to benzene has been trapped. The synthetic utility of the newly installed Al−H bonds has been demonstrated by their ability to reduce CO2 under mild conditions to form the bis‐formate AM[Al(NONDipp)(O2CH)2] compounds, which exhibit a diverse series of eyecatching bimetallacyclic structures. [ABSTRACT FROM AUTHOR]

Focused-electron-beam-induced deposition (FEBID) is a powerful nanopatterning technique where electrons trigger the local dissociation of precursor molecules, leaving a deposit of non-volatile dissociation products. The fabrication of high-purity gold deposits via FEBID has significant potential to expand the scope of this method. For this, gold precursors that are stable under ambient conditions but fragment selectively under electron exposure are essential. Here, we investigated the potential gold precursor (CH3)AuP(CH3)3 using FEBID under ultra-high vacuum (UHV) and spectroscopic characterization of the corresponding metal-containing deposits. For a detailed insight into electron-induced fragmentation, the deposit's composition was compared with the fragmentation pathways of this compound through dissociative ionization (DI) under single-collision conditions using quantum chemical calculations to aid the interpretation of these data. Further comparison was made with a previous high-vacuum (HV) FEBID study of this precursor. The average loss of about 2 carbon and 0.8 phosphor per incident was found in DI, which agreed well with the carbon content of the UHV FEBID deposits. However, the UHV deposits were found to be as good as free of phosphor, indicating that the trimethyl phosphate is a good leaving group. Differently, the HV FEBID experiments showed significant phosphor content in the deposits. [ABSTRACT FROM AUTHOR]

The chiral building block (R)-(+)-2,2′-diamino-1,1′-binaphthyl, (R)-BINAM, which is often used as backbone in privileged enantioselective catalysts, was converted to a series of N-substituted proligands R1-H2 (R = CH2tBu, C(H)Ph2, PPh2, dibenzosuberane, 8-quinoline). After double deprotonation with strong Mg or Ca bases, a series of alkaline earth (Ae) metal catalysts R1-Ae·(THF)n was obtained. Crystal structures of these C2-symmetric catalysts have been analyzed by quadrant models which show that the ligands with C(H)Ph2, dibenzosuberane and 8-quinoline substituents should give the best steric discrimination for the enantioselective intramolecular alkene hydroamination (IAH) of the aminoalkenes H2C＝CHCH2CR′2CH2NH2 (CR′2 = CPh2, CCy or CMe2). The dianionic R12− ligand in R1–Ae·(THF)n functions as reagent that deprotonates the aminoalkene substrate, while the monoanionic (R1-H)− ligand formed in this reaction functions as a chiral spectator ligand that controls the enantioselectivity of the ring closure reaction. Depending on the substituent R in the BINAM ligand, full cyclization of aminoalkenes to chiral pyrrolidine products as fast as 5 minutes was observed. Product analysis furnished enantioselectivities up to 57% ee, which marks the highest enantioselectivity reported for Ca catalyzed IAH. Higher selectivities are impeded by double protonation of the R12− ligand leading to complete loss of chiral information in the catalytically active species. [ABSTRACT FROM AUTHOR]

Commercial LiAlH4 can be used in catalytic quantities in the hydrogenation of imines to amines with H2. Combined experimental and theoretical investigations give deeper insight in the mechanism and identifies the most likely catalytic cycle. Activity is lost when Li in LiAlH4 is exchanged for Na or K. Exchanging Al for B or Ga also led to dramatically reduced activities. This indicates a heterobimetallic mechanism in which cooperation between Li and Al is crucial. Potential intermediates on the catalytic pathway have been isolated from reactions of MAlH4 (M=Li, Na, K) and different imines. Depending on the imine, double, triple or quadruple imine insertion has been observed. Prolonged reaction of LiAlH4 with PhC(H)=NtBu led to a side‐reaction and gave the double insertion product LiAlH2[N]2 ([N]=N(tBu)CH2Ph) which at higher temperature reacts further by ortho‐metallation of the Ph ring. A DFT study led to a number of conclusions. The most likely catalyst for hydrogenation of PhC(H)=NtBu with LiAlH4 is LiAlH2[N]2. Insertion of a third imine via a heterobimetallic transition state has a barrier of +23.2 kcal mol−1 (ΔH). The rate‐determining step is hydrogenolysis of LiAlH[N]3 with H2 with a barrier of +29.2 kcal mol−1. In agreement with experiment, replacing Li for Na (or K) and Al for B (or Ga) led to higher calculated barriers. Also, the AlH4− anion showed very high barriers. Calculations support the experimentally observed effects of the imine substituents at C and N: the lowest barriers are calculated for imines with aryl‐substituents at C and alkyl‐substituents at N. [ABSTRACT FROM AUTHOR]

The dipyrromethene (DPM) ligand is the key to isolation of monomeric Zn hydride complexes with tricoordinate zinc centers. A range of RDPM ligands with various substituents in the pole position (1,9‐positions) were prepared: R = tBu, adamantyl (Ad), mesityl (Mes), 2,6‐diisopropylphenyl (DIPP), 2,4,6‐triphenylphenyl (Mes*), or 9‐anthracenyl (Anth). Reaction of the ligands with Et2Zn gave a series of (RDPM)ZnEt complexes, which were converted with I2 to the corresponding (RDPM)ZnI compounds. The latter reacted by salt metathesis with KN(iPr)HBH3 to the series of Zn hydride complexes (RDPM)ZnH. For ligands with the larger Mes* and Anth substituents, (RDPM)ZnEt was converted to (RDPM)ZnOSiPh3, which after reaction with PhSiH3 gave the hydrides. While Zn hydride complexes with R = tBu or Ad are dimeric, all complexes with aryl‐substituents are monomeric. The aryl groups span a cavity around the metal, blocking dimerization and causing a high‐field shift of the 1H NMR signals due to the ASIS effect. Attempted abstraction of the hydride with B(C6F5)3 led to cleavage of the B‐C6F5 bond. [ABSTRACT FROM AUTHOR]

The dipyrromethene (DPM) ligand is the key to isolation of monomeric Zn hydride complexes with tricoordinate zinc centers. A range of RDPM ligands with various substituents in the pole position (1,9‐positions) were prepared: R = tBu, adamantyl (Ad), mesityl (Mes), 2,6‐diisopropylphenyl (DIPP), 2,4,6‐triphenylphenyl (Mes*), or 9‐anthracenyl (Anth). Reaction of the ligands with Et2Zn gave a series of (RDPM)ZnEt complexes, which were converted with I2 to the corresponding (RDPM)ZnI compounds. The latter reacted by salt metathesis with KN(iPr)HBH3 to the series of Zn hydride complexes (RDPM)ZnH. For ligands with the larger Mes* and Anth substituents, (RDPM)ZnEt was converted to (RDPM)ZnOSiPh3, which after reaction with PhSiH3 gave the hydrides. While Zn hydride complexes with R = tBu or Ad are dimeric, all complexes with aryl‐substituents are monomeric. The aryl groups span a cavity around the metal, blocking dimerization and causing a high‐field shift of the 1H NMR signals due to the ASIS effect. Attempted abstraction of the hydride with B(C6F5)3 led to cleavage of the B‐C6F5 bond. [ABSTRACT FROM AUTHOR]

Alkaline earth metal (Ae) chemistry with the anion [N(C6F5)2]− has been explored. Deprotonation of the amine (C6F5)2NH, abbreviated in here as NFH, with 0.5 equivalent of AeN′′2 (N′′ = N(SiMe3)2) is fast and gave, dependent on the solvent, the complexes AeNF2, AeNF2·(THF)2 and AeNF2·(Et2O)2 (Ae = Mg, Ca, Sr). Using a 1/1 ratio, mixed amide complexes were obtained: NFAeN′′ (Ae = Mg, Ca, Sr). Crystal structures of the monomers AeNF2·(THF)2 (Ae = Mg, Ca, Sr) and AeNF2·(Et2O)2 (Ae = Mg, Ca) are presented and compared with those of AeN′′2·(THF)2. In addition, crystal structures of the homoleptic dimer (MgNF2)2 and the heteroleptic dimers (NFAeN′′)2 (Ae = Mg, Ca, Sr) are discussed. All structures are strongly influenced by very short Ae⋯F contacts down to circa 2.11 Å (Mg), 2.50 Å (Ca) and 2.73 Å (Sr). AIM analysis illustrates that, although Ae⋯F contacts are short, there is no bond-critical-point along this axis, indicating an essentially electrostatic interaction. The monomeric complexes feature strong C6F5⋯C6F5 π-stacking, resulting in unusually acute NF–Ae–NF angles as small as 95°. Heteroleptic (NFAeN′′)2 complexes retain their dimeric structure in C6D6 solution and there is no indication of ligand scrambling by the Schlenk equilibrium, suggesting that an electron withdrawing ligand may stabilize heteroleptic complexes. According to DFT calculations, the heteroleptic arrangement is 70 kJ mol−1 more stable than the homoleptic dimers. The Lewis acidity of MgNF2 has been quantified with the Gutmann–Beckett method and by calculation of the Fluoride-Ion-Affinity. The latter calculations show that the Lewis acidity of MgNF2 and CaNF2 is comparable to that of B(C6F5)3. Dimeric (MgNF2)2 fully abstracts Et3PO from Et3PO·B(C6F5)3 and may have potential in Lewis acid catalysis. [ABSTRACT FROM AUTHOR]

The steric bulk of the well‐known DIPPBDI ligand (CH[C(CH3)N‐DIPP]2, DIPP=2,6‐diisopropylphenyl) was increased by replacing isopropyl for isopentyl groups. This very bulky DIPePBDI ligand could not stabilize the radical species (DIPePBDI)Mg.: reduction of (DIPePBDI)MgI with Na gave (DIPePBDI)2Mg2 with a rather long Mg‐Mg bond of 3.0513(8) Å. Addition of TMEDA prior to reduction gave complex (DIPePBDI)2Mg2(C6H6), which could also be obtained as its THF adduct. It is speculated that combination of a bulky spectator ligand and TMEDA prevents dimerization of the intermediate MgI radical, which then reacts with the benzene solvent. Complex (DIPePBDI)2Mg2(C6H6), which formally contains the anti‐aromatic anion C6H62−, reacted with tBuOH as a Brønsted base to 1,3‐ and 1,4‐cyclohexadiene and with H2 as a two electron donor to (DIPePBDI)2Mg2H2 and C6H6. It also reductively cleaved the C−F bond in fluorobenzene and gave (DIPePBDI)MgPh, (DIPePBDI)MgF, and C6H6. Pepping up chemistry with DIPeP: Replacing the isopropyl groups in a commonly used β‐diketiminate ligand for isopentyl substituents gives the super bulky DIPePBDI ligand. Its dinuclear MgI complex, (DIPePBDI)2Mg2, features a strongly elongated Mg−Mg bond. Attempted isolation of the radical (DIPePBDI)Mg. gave (DIPePBDI)2Mg2(C6H6) in which the formally reduced benzene, C6H62−, is a very strong reductant. [ABSTRACT FROM AUTHOR]

Abstract: Imine‐to‐amine conversion with catalytic instead of stoichiometric quantities of LiAlH4 is demonstrated (85 °C, catalyst loading≥2.5 mol %, pressure≥1 bar). The effects of temperature, pressure, solvent, and catalyst modifications, as well as the substrate scope are discussed. Experimental investigations and preliminary DFT calculations suggest that the catalytically active species is generated in situ: LiAlH4+Ph(H)C=NtBu→LiAlH2[N(tBu)CH2Ph]2. A cooperative mechanism in which Li and Al both play a prominent role is proposed. [ABSTRACT FROM AUTHOR]

Three distinct routes are reported to the soluble, dihydridoaluminate compounds, AM[Al(NON Dipp )(H) 2 ] (AM=Li, Na, K, Rb, Cs; [NON Dipp ] 2- =[O(SiMe 2 NDipp) 2 ] 2- ; Dipp=2,6-iPr 2 C 6 H 3 ) starting from the alkali metal aluminyls, AM[Al(NON Dipp )]. Direct H 2 hydrogenation of the heavier analogues (AM=Rb, Cs) produced the first examples of structurally characterized rubidium and caesium dihydridoaluminates, although harsh conditions were required for complete conversion. Using 1,4-cyclohexadiene (1,4-CHD) as an alternative hydrogen source in transfer hydrogenation reactions provided a lower energy pathway to the full series of products for AM=Li-Cs. A further moderation in conditions was noted for the thermal decomposition of the (silyl)(hydrido)aluminates, AM[Al(NON Dipp )(H)(SiH 2 Ph)]. Probing the reaction of Cs[Al(NON Dipp )] with 1,4-CHD provided access to a novel inverse sandwich complex, [{Cs(Et 2 O)} 2 {Al(NON Dipp )(H)} 2 (C 6 H 6 )], containing the 1,4-dialuminated [C 6 H 6 ] 2- dianion and representing the first time that an intermediate in the commonly utilized oxidation process of 1,4-CHD to benzene has been trapped. The synthetic utility of the newly installed Al-H bonds has been demonstrated by their ability to reduce CO 2 under mild conditions to form the bis-formate AM[Al(NON Dipp )(O 2 CH) 2 ] compounds, which exhibit a diverse series of eyecatching bimetallacyclic structures., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

We report the oxidative addition of phenylsilane to the complete series of alkali metal ( AM ) aluminyls [ AM {Al(NON Dipp )}] 2 ( AM = Li, Na, K, Rb, and Cs). Crystalline products ( 1-AM ) have been isolated as ether or THF adducts, [ AM (L) n ][Al(NON Dipp )(H)(SiH 2 Ph)] ( AM = Li, Na, K, Rb, L = Et 2 O, n = 1; AM = Cs, L = THF, n = 2). Further to this series, the novel rubidium rubidiate, [{Rb(THF) 4 } 2 (Rb{Al(NON Dipp )(H)(SiH 2 Ph)} 2 )] + [Rb{Al(NON Dipp )(H)(SiH 2 Ph)} 2 ] - , was isolated during an attempted recrystallization of Rb[Al(NON Dipp )(H)(SiH 2 Ph)] from a hexane/THF mixture. Structural and spectroscopic characterizations of the series 1-AM confirm the presence of μ-hydrides that bridge the aluminum and alkali metals ( AM ), with multiple stabilizing AM ···π(arene) interactions to either the Dipp- or Ph-substituents. These products form a complete series of soluble, alkali metal (hydrido) aluminates that present a platform for further reactivity studies.

Rare examples of heavier alkali metal manganates [{(AM)Mn(CH 2 SiMe 3 )(N 'Ar ) 2 } ∞ ] (AM=K, Rb, or Cs) [N 'Ar =N(SiMe 3 )(Dipp), where Dipp=2,6-iPr 2 -C 6 H 3 ] have been synthesised with the Rb and Cs examples crystallographically characterised. These heaviest manganates crystallise as polymeric zig-zag chains propagated by AM⋅⋅⋅π-arene interactions. Key to their preparation is to avoid Lewis base donor solvents. In contrast, using multidentate nitrogen donors encourages ligand scrambling leading to redistribution of these bimetallic manganate compounds into their corresponding homometallic species as witnessed for the complete Li - Cs series. Adding to the few known crystallographically characterised unsolvated and solvated rubidium and caesium s-block metal amides, six new derivatives ([{AM(N 'Ar )} ∞ ], [{AM(N 'Ar )⋅TMEDA} ∞ ], and [{AM(N 'Ar )⋅PMDETA} ∞ ] where AM=Rb or Cs) have been structurally authenticated. Utilising monodentate diethyl ether as a donor, it was also possible to isolate and crystallographically characterise sodium manganate [(Et 2 O) 2 Na( n Bu)Mn[(N 'Ar ) 2 ], a monomeric, dinuclear structure prevented from aggregating by two blocking ether ligands bound to sodium., (© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Focused-electron-beam-induced deposition (FEBID) is a powerful nanopatterning technique where electrons trigger the local dissociation of precursor molecules, leaving a deposit of non-volatile dissociation products. The fabrication of high-purity gold deposits via FEBID has significant potential to expand the scope of this method. For this, gold precursors that are stable under ambient conditions but fragment selectively under electron exposure are essential. Here, we investigated the potential gold precursor (CH 3 )AuP(CH 3 ) 3 using FEBID under ultra-high vacuum (UHV) and spectroscopic characterization of the corresponding metal-containing deposits. For a detailed insight into electron-induced fragmentation, the deposit's composition was compared with the fragmentation pathways of this compound through dissociative ionization (DI) under single-collision conditions using quantum chemical calculations to aid the interpretation of these data. Further comparison was made with a previous high-vacuum (HV) FEBID study of this precursor. The average loss of about 2 carbon and 0.8 phosphor per incident was found in DI, which agreed well with the carbon content of the UHV FEBID deposits. However, the UHV deposits were found to be as good as free of phosphor, indicating that the trimethyl phosphate is a good leaving group. Differently, the HV FEBID experiments showed significant phosphor content in the deposits.

The chiral building block (R)-(+)-2,2'-diamino-1,1'-binaphthyl, (R)-BINAM, which is often used as backbone in privileged enantioselective catalysts, was converted to a series of N-substituted proligands R1-H2 (R = CH2tBu, C(H)Ph2, PPh2, dibenzosuberane, 8-quinoline). After double deprotonation with strong Mg or Ca bases, a series of alkaline earth (Ae) metal catalysts R1-Ae·(THF)n was obtained. Crystal structures of these C2-symmetric catalysts have been analyzed by quadrant models which show that the ligands with C(H)Ph2, dibenzosuberane and 8-quinoline substituents should give the best steric discrimination for the enantioselective intramolecular alkene hydroamination (IAH) of the aminoalkenes H2C[double bond, length as m-dash]CHCH2CR'2CH2NH2 (CR'2 = CPh2, CCy or CMe2). The dianionic R12- ligand in R1-Ae·(THF)n functions as reagent that deprotonates the aminoalkene substrate, while the monoanionic (R1-H)- ligand formed in this reaction functions as a chiral spectator ligand that controls the enantioselectivity of the ring closure reaction. Depending on the substituent R in the BINAM ligand, full cyclization of aminoalkenes to chiral pyrrolidine products as fast as 5 minutes was observed. Product analysis furnished enantioselectivities up to 57% ee, which marks the highest enantioselectivity reported for Ca catalyzed IAH. Higher selectivities are impeded by double protonation of the R12- ligand leading to complete loss of chiral information in the catalytically active species.

Commercial LiAlH 4 can be used in catalytic quantities in the hydrogenation of imines to amines with H 2 . Combined experimental and theoretical investigations give deeper insight in the mechanism and identifies the most likely catalytic cycle. Activity is lost when Li in LiAlH 4 is exchanged for Na or K. Exchanging Al for B or Ga also led to dramatically reduced activities. This indicates a heterobimetallic mechanism in which cooperation between Li and Al is crucial. Potential intermediates on the catalytic pathway have been isolated from reactions of MAlH 4 (M=Li, Na, K) and different imines. Depending on the imine, double, triple or quadruple imine insertion has been observed. Prolonged reaction of LiAlH 4 with PhC(H)=NtBu led to a side-reaction and gave the double insertion product LiAlH 2 [N] 2 ([N]=N(tBu)CH 2 Ph) which at higher temperature reacts further by ortho-metallation of the Ph ring. A DFT study led to a number of conclusions. The most likely catalyst for hydrogenation of PhC(H)=NtBu with LiAlH 4 is LiAlH 2 [N] 2 . Insertion of a third imine via a heterobimetallic transition state has a barrier of +23.2 kcal mol -1 (ΔH). The rate-determining step is hydrogenolysis of LiAlH[N] 3 with H 2 with a barrier of +29.2 kcal mol -1 . In agreement with experiment, replacing Li for Na (or K) and Al for B (or Ga) led to higher calculated barriers. Also, the AlH 4 - anion showed very high barriers. Calculations support the experimentally observed effects of the imine substituents at C and N: the lowest barriers are calculated for imines with aryl-substituents at C and alkyl-substituents at N., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Preference for the binding mode of the CN - ligand to Mg (Mg-CN vs. Mg-NC) is investigated. A monomeric Mg complex with a terminal CN ligand was prepared using the dipyrromethene ligand Mes DPM which successfully blocks dimerization. While reaction of ( Mes DPM)MgN(SiMe 3 ) 2 with Me 3 SiCN gave the coordination complex ( Mes DPM)MgN(SiMe 3 ) 2 ⋅NCSiMe 3 , reaction with ( Mes DPM)Mg(nBu) led to ( Mes DPM)MgNC⋅(THF) 2 . A Mg-NC/Mg-CN ratio of ≈95:5 was established by crystal-structure determination and DFT calculations. IR studies show absorbances for CN stretching at 2085 cm -1 (Mg-NC) and 2162 cm -1 (Mg-CN) as confirmed by 13 C labeling. In solution and in the solid state, the CN ligand rotates within the pocket. The calculated isomerization barrier is only 12.0 kcal mol -1 and the 13 C NMR signal for CN decoalesces at -85 °C (Mg-NC: 175.9 ppm, Mg-CN: 144.3 ppm). Experiment and theory both indicate that Mg complexes with the CN - ligand should not be named cyanides but are more properly defined as isocyanides., (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Alkaline earth metal (Ae) chemistry with the anion [N(C 6 F 5 ) 2 ] - has been explored. Deprotonation of the amine (C 6 F 5 ) 2 NH, abbreviated in here as N F H, with 0.5 equivalent of AeN'' 2 (N'' = N(SiMe 3 ) 2 ) is fast and gave, dependent on the solvent, the complexes AeN F 2 , AeN F 2 ·(THF) 2 and AeN F 2 ·(Et 2 O) 2 (Ae = Mg, Ca, Sr). Using a 1/1 ratio, mixed amide complexes were obtained: N F AeN'' (Ae = Mg, Ca, Sr). Crystal structures of the monomers AeN F 2 ·(THF) 2 (Ae = Mg, Ca, Sr) and AeN F 2 ·(Et 2 O) 2 (Ae = Mg, Ca) are presented and compared with those of AeN'' 2 ·(THF) 2 . In addition, crystal structures of the homoleptic dimer (MgN F 2 ) 2 and the heteroleptic dimers (N F AeN'') 2 (Ae = Mg, Ca, Sr) are discussed. All structures are strongly influenced by very short AeF contacts down to circa 2.11 Å (Mg), 2.50 Å (Ca) and 2.73 Å (Sr). AIM analysis illustrates that, although AeF contacts are short, there is no bond-critical-point along this axis, indicating an essentially electrostatic interaction. The monomeric complexes feature strong C 6 F 5 C 6 F 5 π-stacking, resulting in unusually acute N F -Ae-N F angles as small as 95°. Heteroleptic (N F AeN'') 2 complexes retain their dimeric structure in C 6 D 6 solution and there is no indication of ligand scrambling by the Schlenk equilibrium, suggesting that an electron withdrawing ligand may stabilize heteroleptic complexes. According to DFT calculations, the heteroleptic arrangement is 70 kJ mol -1 more stable than the homoleptic dimers. The Lewis acidity of MgN F 2 has been quantified with the Gutmann-Beckett method and by calculation of the Fluoride-Ion-Affinity. The latter calculations show that the Lewis acidity of MgN F 2 and CaN F 2 is comparable to that of B(C 6 F 5 ) 3 . Dimeric (MgN F 2 ) 2 fully abstracts Et 3 PO from Et 3 PO·B(C 6 F 5 ) 3 and may have potential in Lewis acid catalysis.

The steric bulk of the well-known DIPP BDI ligand (CH[C(CH 3 )N-DIPP] 2 , DIPP=2,6-diisopropylphenyl) was increased by replacing isopropyl for isopentyl groups. This very bulky DIPeP BDI ligand could not stabilize the radical species ( DIPeP BDI)Mg . : reduction of ( DIPeP BDI)MgI with Na gave ( DIPeP BDI) 2 Mg 2 with a rather long Mg-Mg bond of 3.0513(8) Å. Addition of TMEDA prior to reduction gave complex ( DIPeP BDI) 2 Mg 2 (C 6 H 6 ), which could also be obtained as its THF adduct. It is speculated that combination of a bulky spectator ligand and TMEDA prevents dimerization of the intermediate Mg I radical, which then reacts with the benzene solvent. Complex ( DIPeP BDI) 2 Mg 2 (C 6 H 6 ), which formally contains the anti-aromatic anion C 6 H 6 2- , reacted with tBuOH as a Brønsted base to 1,3- and 1,4-cyclohexadiene and with H 2 as a two electron donor to ( DIPeP BDI) 2 Mg 2 H 2 and C 6 H 6 . It also reductively cleaved the C-F bond in fluorobenzene and gave ( DIPeP BDI)MgPh, ( DIPeP BDI)MgF, and C 6 H 6 ., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Imine-to-amine conversion with catalytic instead of stoichiometric quantities of LiAlH 4 is demonstrated (85 °C, catalyst loading≥2.5 mol %, pressure≥1 bar). The effects of temperature, pressure, solvent, and catalyst modifications, as well as the substrate scope are discussed. Experimental investigations and preliminary DFT calculations suggest that the catalytically active species is generated in situ: LiAlH 4 +Ph(H)C=NtBu→LiAlH 2 [N(tBu)CH 2 Ph] 2 . A cooperative mechanism in which Li and Al both play a prominent role is proposed., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Reaction of Ba[N(SiMe 3 ) 2 ] 2 with PhSiH 3 in toluene gave simple access to the unique Ba hydride cluster Ba 7 H 7 [N(SiMe 3 ) 2 ] 7 that can be described as a square pyramid spanned by five Ba 2+ ions with two flanking BaH[N(SiMe 3 ) 2 ] units. This heptanuclear cluster is well soluble in aromatic solvents, and the hydride 1 H NMR signals and coupling pattern suggests that the structure is stable in solution. At 95 °C, no coalescence of hydride signals is observed but the cluster slowly decomposes to undefined barium hydride species. The complex Ba 7 H 7 [N(SiMe 3 ) 2 ] 7 is a very strong reducing agent that already at room temperature reacts with Me 3 SiCH=CH 2 , norbornadiene, and ethylene. The highly reactive alkyl barium intermediates cannot be observed and deprotonate the (Me 3 Si) 2 N - ion, as confirmed by the crystal structure of Ba 14 H 12 [N(SiMe 3 ) 2 ] 12 [(Me 3 Si)(Me 2 SiCH 2 )N] 4 ., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)