
==== Front
Chem Sci
Chem Sci
SC
CSHCBM
Chemical Science
2041-6520
2041-6539
The Royal Society of Chemistry

39184294
d4sc03926b
10.1039/d4sc03926b
Chemistry
Synthesis of bismuthanyl-substituted monomeric triel hydrides†‡
† In memoriam on Ian Manners.

‡ Electronic supplementary information (ESI) available. CCDC 2347535 and 2340840–2340842. For ESI and crystallographic data in CIF or other electronic format see DOI: https://doi.org/10.1039/d4sc03926b

Szlosek Robert a
Marquardt Christian a
Hegen Oliver a
Balázs Gábor a
Riesinger Christoph a
https://orcid.org/0000-0002-1932-6647
B-1174-2012
Timoshkin Alexey Y. b
https://orcid.org/0000-0003-2182-5020
J-3232-2016
Scheer Manfred a
a Institute of Inorganic Chemistry, University of Regensburg 93053 Regensburg Germany manfred.scheer@ur.de

b Institute of Chemistry, St. Petersburg State University Universitetskaya nab. 7/9 199034 St. Petersburg Russia
12 8 2024
18 9 2024
12 8 2024
15 36 1483714843
15 6 2024
9 8 2024
This journal is © The Royal Society of Chemistry
2024
The Royal Society of Chemistry
https://creativecommons.org/licenses/by-nc/3.0/ This article is licensed under a Creative Commons Attribution-Non Commercial 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.
The syntheses and characterizations of the first bismuthanylborane monomers stabilized only by a donor in D·BH2Bi(SiMe3)2 (D = DMAP 1a, IDipp 1b, IMe41c; DMAP = 4-dimethylaminopyridine, IDipp = 1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene, IMe4 = 1,3,4,5-tetramethylimidazol-2-ylidene) are presented. All compounds were synthesized by salt metathesis reactions between D·BH2I and KBi(SiMe3)2(THF)0.3 and represent some of the extremely rare compounds featuring a 2c–2e B–Bi bond in a molecular compound. The products display high sensitivity towards air and light and slowly decompose in solution even at −80 °C. By the reaction of IDipp·GaH2(SO3CF3) with KBi(SiMe3)2(THF)0.3, the synthesis of the first bismuthanylgallane IDipp·GaH2Bi(SiMe3)2 (2) stabilized only by a 2-electron donor was possible, as evident from single crystal X-ray structure determination, NMR spectroscopy and mass spectrometry. Computational studies shed light on the stability of the products and the electronic nature of the compounds.

The syntheses of first, extremely sensitive donor-stabilized monomeric bismuthanylboranes D·BH2Bi(SiMe3)2 (D = NHC, DMAP) and the bismuthanylgallane IDipp·GaH2Bi(SiMe3)2 are presented representing unique element combinations of bismuth and triels.

Fonds der Chemischen Industrie 10.13039/100018992 Sche 384/41-1 Russian Science Foundation 10.13039/501100006769 21-43-04404 pubstatusPaginated Article
==== Body
pmcThe attention paid to the chemistry of bismuth has increased tremendously within the last decade.1–4 As bismuth can adopt all oxidation states from +V to −III and can often feature a stereoactive 6s atomic orbital, it is capable of extraordinary structural diversity. What is more, strong spin–orbit coupling and relativistic effects influence the chemical and physical properties of bismuth compounds.5 Prominent representatives for this flexibility are e.g. highly charged bismuth cluster anions.2,6 The flexibility of binding modes makes organic and inorganic bismuth compounds very useful reagents. E.g. inorganic salts BiX3 (X = Hal, OTf, NO3; OTf = SO3CF3) have been commonly employed in organic transformations either stoichiometrically or catalytically.7

In addition, more and more new bismuth-based catalyst systems have recently been developed, capable of impressive organic transformations.3,8 For instance, the Cornella group has pushed the boundaries of bismuth-catalysed organic transformations ranging from transfer hydrogenations and amide reductions to oxidative coupling reactions and many other applications.4,9–12 Significantly, it could be demonstrated that bismuth-based catalysis not only relies on the Lewis acidic properties of Bi(iii), but that the latter also displays reaction behaviour similar to regular transition metals since important steps such as single-electron transfer can also be achieved.10–12

Important contributions to the chemistry of trivalent bismuth were also attained by Chitnis and co-workers who exploited the geometric perturbation of planar trivalent bismuthanes to achieve an unusual reactivity thanks to the steric and electronic properties of these compounds.13,14 Furthermore, planar Bi(iii) complexes proved to act as tuneable platforms for catalytic ring opening polymerizations of cyclic esters with good dispersity values and high molecular weights, with only low quantities of the corresponding bismuth triamide catalyst being needed.14 The success of Bi in catalysis is based on rather strong Bi–C bonds, whereas Bi–triel bonds (triel = group 13 element) often suffer weak bonding because of rather low bond dissociation enthalpies. Thus, isolated examples of such compounds are quite rare, especially when heavy triels come into play. Therefore, such compounds are often unstable and difficult to isolate without prior decomposition.

To the best of our knowledge, the only examples of isolable compounds featuring covalent B–Bi compounds are found in a boryldiphenylbismuthane (Fig. 1, I)15 as well as in a boryl-dibismuthene (Fig. 1, II).16 Here, the B atom is incorporated in a stabilizing cycle. The von Hänisch group made important contributions to the field of covalent bismuth compounds and could obtain several highly sensitive interpnictogen chain compounds that include bismuth.17 This group was recently also able to report on donor-free bismuth cations capable of intriguing reactivity.18 The group of S. Schulz further advanced this field by the activation of bismuthanes with monovalent group 13 compounds of (Dipp2Nacnac)M (dipp = 2,6 diisopropylphenyl, M = Al, Ga, In; Fig. 1, IIIa–c, IVa).19 R. A. Fischer and co-workers reported similar dibismuthenes supported by (Dipp2Nacnac)Ga as well as (IVb/c).20 Von Hänisch and co-workers were able to synthesize similar compounds by a related strategy (Fig. 1, V, VI, VIIa/b).21 Again, also in these compounds, the group 13 element is embedded in a cyclic system. Very recently, the groups of Coles and McMullin synthesized a unique bicyclic-like compound featuring a covalent 2c–2e In–Bi bond (Fig. 1, VIII).22 However, in all reports about Bi–triel bonded compounds, none of the mentioned examples contained parent H-substituted triel moieties and they were all embedded in chain compounds.

Fig. 1 Selected examples of stabilization motifs of molecular 13/15 compounds featuring E–Bi bonds in (a) cyclic systems, (b) stabilized by β-diketiminates and (c) in bicyclic systems (Mes = 2,4,6-trimethylphenyl, dipp = 2,6-diisopropylphenyl, E = triel, Nacnac = bis(2,6-diaryl)-2,2'dimethyl-β-diketiminate); (d) bismuthanyl-substituted triel hydrides presented in this work.

Our group is interested in the stabilization of parent group 13/15 element compounds stabilized only by Lewis acids or bases, which can be used e.g. as building blocks for selective oligo- and polymerization reactions.23 These monomers are usually synthesized by salt metathesis or hydrogen elimination reactions and show interesting reactivities towards electrophiles and nucleophiles.24 The group 15 element within such compounds also enables a broad range of coordination possibilities,25,26 even leading to promising luminescent materials.26 By varying the group 15 element, the parent phosphanyl-, arsanyl- as well as stibanylboranes stabilized only by one donor molecule D·BH2PnH2 (Pn = P, As, Sb) could be accessed.27,28 The corresponding phosphanyl- and arsanylgallanes and -alanes IDipp·EH2PnH2 (E = Ga, Al; Pn = P, As) were also recently obtained, but only with the support of a bulky N-heterocyclic carbene (NHC) as donor.29,30 Higher degrees of substitution at the group 13 entities could also be achieved by multiple salt metatheses, leading to the compounds IDipp·EH3−x(PnH2)x (x = 2, 3) and even the triphosphanylindiumane IDipp·In(PH2)3.30,31

Whereas phosphanyl-, arsanyl- and stibanylboranes have already been synthesized, the synthesis of the homologous bismuthanylboranes has so far not been realized. So, the question is whether such compounds are accessible and, if so, whether it is possible to synthesize even the parent compounds. Herein, we report on the synthesis of the first chain-like, donor-stabilized bismuthanylboranes featuring covalent 2c–2e electron B–Bi bonds which contain unique BH2-moieties as well as on the isolation of an unprecedented bismuthanylgallane, making each of them the first representatives of their particular kinds.1

The first step was to target the synthesis of a suitable bismuth source to use it to prepare the donor-stabilized bismuthanylboranes. As salt metathesis presents a reliable pathway towards this type of 13/15 compounds, we started off by investigating the salt metathesis of D·BH2I with an alkali metal bismuthanide. Unfortunately, MBiH2 (M = alkali metal) remains inaccessible so that we decided to introduce SiMe3 groups by using MBi(SiMe3)2,32 which offers the possibility towards future Bi–Si bond cleavage. KBi(SiMe3)2(THF)0.3 was prepared by the reaction of Bi(SiMe3)3 with KOtBu in THF (cf. ESI‡).

Subsequently, this reagent was reacted with iodinated donor-stabilized boranes D·BH2I (D = IDipp, IMe4 (=1,3,4,5-tetramethylimidazol-2-ylidene), DMAP) by adding neat KBi(SiMe3)2(THF)0.3 to a cold solution (−80 °C) of the corresponding boranes in THF under exclusion of light (eqn (1)). Upon reaching room temperature, full conversion of the starting materials is achieved according to NMR spectroscopy. After extraction with toluene, the donor-stabilized bismuthanylboranes D·BH2Bi(SiMe3)2 (1a: D = IDipp, 1b: D = IMe4, 1c D = DMAP) were obtained in moderate to good yields. The compounds are obtained as grey powders, which display very high sensitivity towards air and light and decompose at room temperature under visible deposition of elemental bismuth. A very slow decomposition occurs even upon prolonged storage at −30 °C, complicating the storage of the solid products for longer than a month.

Decomposition in solution happens even faster and at temperatures as low as −80 °C, with 1c displaying the highest tendency towards decomposition. Presumably, the donor strength of NHCs significantly contributes to the overall better kinetic and thermodynamic stability of the compounds which keeps the molecules intact. This is further supported by quantum chemical calculations (vide infra), which show a higher dissociation energy for the NHC adducts 1a and 1b. Furthermore, this is in line with the isolated yields from the reactions (cf.eqn (1)). The NMR spectra of solutions of 1a–c in C6D6 show characteristic triplet resonances in the 11B NMR spectra and singlets (Si(CH3)3) as well as broadened quartets (BH2) in the 1H NMR spectra (cf.Table 1). Moreover, 1a and 1b could also be characterized by their molecular ion peaks at m/z = 756.44 (1a) and m/z = 492.20 (1b) in the LIFDI mass spectra. It was also possible to crystallize all bismuthanylboranes 1a–c by storing saturated solutions in n-hexane (1b) or toluene (1c) at −30 °C overnight or slow evaporation (1a) of n-pentane at −30 °C. By single-crystal X-ray structure determination, the structures in the solid state could be elucidated (Fig. 2).

Characteristic NMR signals of compounds 1a–2 [ppm] (C6D6, 298 K; s = singlet, t = triplet, br = broadened)

NMR spectrum	1a	1b	1c	2	
1H Si(CH3)3 signal	0.53, s	0.81, s	0.95, s	0.70, s	
1H EH2 signal (E = B, Ga)	2.24, q, br 1JBH = 100 Hz	2.43, q, br 1JBH = 107 Hz	4.74, q, br 1JBH = 120 Hz	4.97, s, br	
11B{1H}	−42.1, s, br	−39.5, s, br	−15.4, s, br	—	
11B	−42.1, t, br 1JBH = 100 Hz	−39.5, t, br 1JBH = 107 Hz	−15.2, t, br 1JBH = 120 Hz	—	

Fig. 2 Molecular structures of 1a, 1b and 1c in the solid state. Anisotropic displacement ellipsoids are shown at 50% probability level. Hydrogen atoms bound to carbon are omitted for clarity. Dipp groups are displayed as stick models for improved clarity. Selected bond lengths and angles: 1a C40–B2 1.587(7), B2–Bi2 2.424(5), Bi2–Si2 2.639(4), Bi2–Si3 2.6494(15), C40–B2–Bi2 110.9(3), B2–Bi2–Si2 90.86(15), B2–Bi2–Si3 97.09(14). 1b C1–B1 1.569(9), B1–Bi1 2.442(7), Bi1–Si1 2.6278(17), Bi1–Si2 2.6452(18), C1–B1–Bi1 107.2(4), B1–Bi1–Si1 89.12(18), B1–Bi1–Si2 97.05(19). 1c N1–B1 1.578(5), B1–Bi1 2.424(5), Bi1–Si1 2.6331(9), Bi1–Si2 2.6322(11), N1–B1–Bi1 106.9(2), B1–Bi1–Si1 94.53(10), B1–Bi1–Si2 100.10(12).

1a and 1b show eclipsed conformations at the chain positions, whereas 1c is arranged in a gauche conformation (cf.Fig. 2 and 3). All atoms within the core structure motifs are bound in a (pseudo)tetrahedral manner, with the B–Bi–Si bond angles bent at almost 90° as a result of very poor s–p orbital mixing (1a: 90.83(13)° & 97.10(12)°; 1b: 89.12(18)° & 97.05(19)°, 1c: 94.53(10)° & 100.10(12)°), which is significantly lower than for the lighter homologs (cf. Me3N·BH2P(SiMe3)2: Si–P–B 102.30(8)°).28

Fig. 3 Structural features derived by X-ray crystallographic structure determination of 1a–c including key bond distances [Å] and angles (top). Bottom: Newman projections along the B–Bi σ-bonds alongside the corresponding dihedral angles.

The B–Bi bond distances of 1a–c are between 2.423(4) Å and 2.442(7) Å and represent the first known examples of B–Bi 2c–2e bonds with tetracoordinate boron atoms within chain compounds. Compared to the B–Bi bonds in boryldiphenylbismuthane I (B–Bi: 2.343(6) Å)15 and boryldibismuthene II (B–Bi: 2.326(7)/2.317(9) Å),16 the bonds are significantly elongated due to the different electronic and steric environment of, especially, the boron atom.

The SiMe3 groups on the Bi atom of 1a–c provided a possible opportunity to generate the only hydrogen-substituted parent compounds of 1a–c D·BH2BiH2 by cleavage of the SiMe3 residues. Attempts at the cleavage of the SiMe3 groups were performed by the addition of MeOH, mixtures of MeOH/MeONa, hexanol or KF·HF. In all cases, however, only decomposition products or unreacted starting materials could be detected. The most promising attempt was the reaction of 1a with 1,4-benzoquinone as a {SiMe3} scavenger in the presence of MeOH-d4 in THF (cf. ESI‡), which showed the cleavage of at least one {SiMe3} group at the bismuth atom in the 1H NMR spectrum of the reaction mixture. Simultaneously, besides unreacted 1a, IDipp·BH2(OMe) and IDipp·BH3, a new, broad signal at −31.4 ppm was detected in the 11B NMR spectrum. The 2H NMR spectrum shows a broad signal at 2.96 ppm but, unfortunately, a clear identification of the product was not possible. Conceivably, IDipp·BH2Bi(SiMe3)2−xDx (x = 1–2) is formed as a transient species, but unequivocal evidence of this species could not be obtained. Hence, despite numerous efforts the parent compounds containing H2Bi–BH2 units have so far remained inaccessible.

After the successful synthesis of donor-stabilized bismuthanylboranes, the question arose as to whether it is also possible to synthesize the heavier gallium homolog. Thus, a reaction between IDipp·GaH2(OTf) and KBi(SiMe3)2(THF)0.3 was attempted. After cooling a solution of IDipp·GaH2(OTf) in tetrahydrofuran to −80 °C, the solid bismuthide was added and the mixture was slowly warmed to room temperature over the course of 18 hours (eqn (2)). The 1H NMR spectrum of the reaction mixture showed full conversion of the starting material (0.63 ppm, CD3CN) with a characteristic singlet including 29Si satellites at 0.71 ppm for the {SiMe3} residues (18H, 2JHSi = 7.15 Hz).2

2 is extremely air-, light- and temperature-sensitive and decomposes very slowly in solution already at −80 °C under deposition to elemental bismuth and other unidentified compounds. The 1H NMR spectra of solutions of 2 in C6D6 show characteristic signals at 0.70 ppm (Si(CH3)3) and 4.97 ppm (GaH2; cf.Table 1). The sensitivity of 2 greatly complicates the handling of the product, but, fortunately, by slow evaporation of a solution of 2 in n-pentane under reduced pressure at −80 °C, it was possible to grow a few single crystals of 2, which were of suitable quality for single crystal X-ray structure determination (Fig. 4). 2 crystallizes in the orthorhombic space group Pbca as clear colourless plate-shaped crystals. The structure in the solid state shows (pseudo)tetrahedral geometries at the [GaH2Bi(SiMe3)2] unit with a Ga–Bi bond length of 2.7234(4) Å, which is only slightly elongated compared to the Ga–Bi bond distance of 2.7171(8) Å of {(Dipp2NacNac)GaHBiMe}2.21 The C1–Ga1–Bi1 angle (110.10(8)°) indicates a tetrahedral geometry at the Ga atom while the Ga1–Bi1–Si1 (95.26(2)°) and Ga1–Bi1–Si2 (87.85(2)°) angles are significantly distorted from a regular tetrahedral binding situation. Similar to 1a and 1b, 2 is arranged in an eclipsed conformation (C1–Ga1–Bi1–Si1: 113.33(9)°). The presence of 2 could also be confirmed by mass spectrometry, as the LIFDI-MS spectrum of a solution of 2 in toluene shows a molecular ion peak at m/z = 814.34 besides the decomposition products [IDipp-H]+ (m/z = 389.31) and [IDipp-GaH2]+ (m/z = 459.24).

Fig. 4 Molecular structure of 2 in the solid state. Anisotropic displacement ellipsoids are shown at 50% probability level. Hydrogen atoms bound to carbon are omitted for clarity. Dipp residues are depicted as stick models for better clarity. Selected bond lengths [Å] and angles [°]: N1–C1 1.352(4), N2–C1 1.357(4), C1–Ga1 2.061(3), Ga1–Bi1 2.7234(4), Bi1–Si1 2.6487(9), Bi1–Si2 2.6403(9), N1–B1–Bi1 106.9(2), N1–C1–N2 104.2(3), N1–C1–Ga1 129.2(2), C1–Ga1–Bi1 110.10(8), Ga1–Bi1–Si1 95.26(2), B1–Bi1–Si2 87.85(2).

To analyse the stability and electronic structure of all obtained products, quantum chemical calculations were performed on 1a–2 (B3LYP/def2-TZVP, ECP on Bi; cf. ESI‡). The stability with respect to the dissociation of the Lewis acid/base adducts decreases in the order of IMe4 > IDipp > DMAP and B > Ga, which is in line with the isolated yields and the observed stabilities in solution. The standard Gibbs energy for the dissociation of 2 into IDipp and GaH2Bi(SiMe3)2 is endergonic only by +27 kJ mol−1, which makes this compound the least stable one within the synthesized series with respect to dissociation. Analyses of structural characteristics, NBO and Wiberg bond indices (WBIs) indicate that upon complex formation, the E–Bi bond distances increase by 0.1–0.2 Å and the WBIs of the E–Bi bonds decrease by 0.1–0.37, in line with the above-mentioned order of thermodynamic stability (cf. ESI‡). The B–Bi bond in free BH2Bi(SiMe3)2 has a partial double bond character (WBI 1.21) due to the π-interaction between the lone pair of Bi (75.5% s character) and the empty orbital of boron (99.4% p-character) with an E(2) value of 3.74 kcal mol−1 (Table S6 in ESI‡). In case of the gallium analogue GaH2Bi(SiMe3)2, the similar π-interaction is much less pronounced (E(2) value 1.59 kcal mol−1) and the WBI value is close to one. The occupancies of vacant p-orbitals on boron (0.17ē) and gallium (0.08ē) also indicate smaller involvement of the Ga atom in π-interactions with Bi. After complexation with IDipp, π-interactions between Bi–B and Bi–Ga are absent in both 1a and 2.

Regarding the methanolysis reactions of 1a–1c, the formation of IDipp·BH2BiH2, IMe4·BH2BiH2 and DMAP·BH2BiH2, respectively, is predicted to be highly exothermic and exergonic by 187–206 kJ mol−1, while the formed hydride compounds are predicted to be thermodynamically unstable with respect to the decomposition to LB·BH3, H2 and solid Bi (processes are exergonic by 120–150 kJ mol−1) (cf. ESI‡).

In summary, it could be shown that the synthesis of donor-stabilized bismuthanylboranes and gallanes can be achieved by salt metathesis with KBi(SiMe3)2(THF)0.3, yielding IDipp·BH2Bi(SiMe3)2 (1a), IMe4·BH2Bi(SiMe3)2 (1b), DMAP·BH2Bi(SiMe3)2 (1c), and IDipp·GaH2Bi(SiMe3)2 (2). All compounds could be characterized by multinuclear NMR spectroscopy and LIFDI-MS. Moreover, the crystal structures of all products 1a–2 could be determined, representing the first solid-state structures of bismuthanyltrielanes that contain parent {EH2} triel moieties and possess E–Bi σ-bonds in chain-like compounds. Specifically, 1a–c represent the first examples of structures containing covalent B–Bi σ-bonds where the boron atom is not embedded in a cyclic system. All compounds display a very high sensitivity towards air and light. Desilylation attempts have been unsuccessful, which is likely to be also due to the extreme instability of the potentially formed {BH2BiH2} moiety. Future investigations will focus on the reactivity of these compounds regarding catenation, coordination as well as deposition experiments.

Data availability

The data supporting this article have been included as part of the ESI.‡ CCDC-2347535 (1a), CCDC-2340840 (1b), CCDC-2340841 (1c), and CCDC-2340842 (2), contain the supplementary crystallographic data for this paper.

Author contributions

R. Szlosek performed the experimental work (incl. reproductions and analytical data of 1b and 1c), wrote the original draft, acquisition (1a, 2) and refinement (2) of X-ray data. C. Marquardt prepared 1c and acquisition/refinement of X-ray data for 1c. O. Hegen prepared 1b and acquisition/refinement of X-ray data for 1b. G. Balázs conceptualization and project management. C. Riesinger performed the refinement of X-ray data for 1a. A. Y. Timoshkin performed quantum chemical calculations, conceptualization, project management. M. Scheer wrote the original draft, supervised the project and conceptualization, funding and project management.

Conflicts of interest

There are no conflicts to declare.

Supplementary Material

SC-015-D4SC03926B-s001

SC-015-D4SC03926B-s002

SC-015-D4SC03926B-s003

This work was supported by a joint DFG-RSF project (DFG Sche 384/41-1, Russian Science Foundation (RSF) grant 21-43-04404). The use of computational resources of the research centre “Computing Center” of the St. Petersburg State University is acknowledged. R. S. is grateful to the Fonds der Chemischen Industrie (FCI) for a PhD fellowship. Matthias Hautmann is acknowledged for the preparation of KBi(SiMe3)2(THF)0.3. Lisa Zimmermann and Dr Martin Weber are acknowledged for fruitful discussions.
==== Refs
Notes and references

(a) Kanatzidis M. Sun H. Dehnen S. Inorg. Chem. 2020 59 3341 10.1021/acs.inorgchem.0c00222 32172571
(b) Ondet P. Lemière G. Duñach E. Eur. J. Org Chem. 2017 2017 761 10.1002/ejoc.201600937
(c) Lopez E. Thorp S. C. Mohan R. S. Polyhedron 2022 222 115765 10.1016/j.poly.2022.115765
Pan F. Peerless B. Dehnen S. Acc. Chem. Res. 2023 56 1018 10.1021/acs.accounts.3c00020 37067095
Ollevier T. Org. Biomol. Chem. 2013 11 2740 10.1039/C3OB26537D 23380745
Moon H. W. Cornella J. ACS Catal. 2022 12 1382 10.1021/acscatal.1c04897 35096470
(a) Gonze X. Michenaud J.-P. Vigneron J.-P. Phys. Scr. 1988 37 785 10.1088/0031-8949/37/5/022
(b) Isaeva A. Ruck M. Inorg. Chem. 2020 59 3437 10.1021/acs.inorgchem.9b03461 32101423
(a) Heine J. Peerless B. Dehnen S. Lichtenberg C. Angew. Chem., Int. Ed. 2023 62 e202218771 10.1002/anie.202218771 36848583
(b) Pan F. Wei S. Guggolz L. Eulenstein A. R. Tambornino F. Dehnen S. J. Am. Chem. Soc. 2021 143 7176 10.1021/jacs.1c02653 33905232
(c) Eulenstein A. R. Franzke Y. J. Bügel P. Massa W. Weigend F. Dehnen S. Nat. Commun. 2020 11 5122 10.1038/s41467-020-18799-6 33046705
(d) Eulenstein A. R. Franzke Y. J. Lichtenberger N. Wilson R. J. Deubner H. L. Kraus F. Clérac R. Weigend F. Dehnen S. Nat. Chem. 2021 13 149 10.1038/s41557-020-00592-z 33288891
(e) Peerless B. Schmidt A. Franzke Y. J. Dehnen S. Nat. Chem. 2023 15 347 10.1038/s41557-022-01099-5 36550232
(a) Bothwell J. M. Krabbe S. W. Mohan R. S. Chem. Soc. Rev. 2011 40 4649 10.1039/C0CS00206B 21589974
(b) Hua R. Curr. Org. Synth. 2008 5 1 10.2174/157017908783497518
(a) Janssen-Müller D. Oestreich M. Angew. Chem., Int. Ed. 2020 59 8328 10.1002/anie.201914729 31916671
(b) Jousseaume B. Laporte C. Toupance T. Bernard J.-M. Tetrahedron Lett. 2002 43 6305 10.1016/S0040-4039(02)01391-6
(c) Kitanosono T. Ollevier T. Kobayashi S. Chem.–Asian J. 2013 8 3051 10.1002/asia.201301149 24101589
(d) Lichtenberg C. Chem. Commun. 2021 57 4483 10.1039/D1CC01284C 33861277
(e) Qin H. Yamagiwa N. Matsunaga S. Shibasaki M. J. Am. Chem. Soc. 2006 128 1611 10.1021/ja056112d 16448133
(f) Qin H. Yamagiwa N. Matsunaga S. Shibasaki M. Angew. Chem., Int. Ed. 2007 46 409 10.1002/anie.200602909 17146812
(g) Ramler J. Krummenacher I. Lichtenberg C. Angew. Chem., Int. Ed. 2019 58 12924 10.1002/anie.201904365 31166083
(h) Rueping M. Nachtsheim B. J. Ieawsuwan W. Adv. Synth. Catal. 2006 348 1033 10.1002/adsc.200606068
(i) Salvador J. A. Silvestre S. M. Tetrahedron Lett. 2005 46 2581 10.1016/j.tetlet.2005.02.080
(j) Vidal S. Synlett 2001 2001 1194 10.1055/s-2001-15163
(k) Worz N. Brandner A. Claus P. J. Phys. Chem. C 2010 114 1164 10.1021/jp909412h
(l) Zhang Z.-P. Dong N. Li X. Chem. Commun. 2017 53 1301 10.1039/C6CC06605D 28070583
(m) Zhou K. Wang W. Zhao Z. Luo G. Miller J. T. Wong M. S. Wei F. ACS Catal. 2014 4 3112 10.1021/cs500530f
(n) Pramanik M. Guerzoni M. G. Richards E. Melen R. L. Angew Chem. Int. Ed. Engl. 2024 63 e202316461 10.1002/anie.202316461 38038149
(o) Mato M. Cornella J. Angew. Chem., Int. Ed. 2024 63 e202315046 10.1002/anie.202315046 37988225
(a) Magre M. Cornella J. J. Am. Chem. Soc. 2021 143 21497 10.1021/jacs.1c11463 34914387
(b) Magre M. Kuziola J. Nöthling N. Cornella J. Org. Biomol. Chem. 2021 19 4922 10.1039/D1OB00367D 33955447
(c) Pang Y. Leutzsch M. Nöthling N. Cornella J. J. Am. Chem. Soc. 2020 142 19473 10.1021/jacs.0c10092 33146996
(d) Pang Y. Leutzsch M. Nöthling N. Katzenburg F. Cornella J. J. Am. Chem. Soc. 2021 143 12487 10.1021/jacs.1c06735 34358426
(e) Wang F. Planas O. Cornella J. J. Am. Chem. Soc. 2019 141 4235 10.1021/jacs.9b00594 30816708
(f) Planas O. Wang F. Leutzsch M. Cornella J. Science 2020 367 313 10.1126/science.aaz2258 31949081
(g) Yang X. Kuziola J. Béland V. A. Busch J. Leutzsch M. Burés J. Cornella J. Angew. Chem., Int. Ed. 2023 e202306447
(h) Yang X. Reijerse E. J. Bhattacharyya K. Leutzsch M. Kochius M. Nöthling N. Busch J. Schnegg A. Auer A. A. Cornella J. J. Am. Chem. Soc. 2022 144 16535 10.1021/jacs.2c05882 36053726
(i) Yang X. Reijerse E. J. Nöthling N. SantaLucia D. J. Leutzsch M. Schnegg A. Cornella J. J. Am. Chem. Soc. 2023 145 5618 10.1021/jacs.2c12564 36854169
(j) Moon H. W. Wang F. Bhattacharyya K. Planas O. Leutzsch M. Nöthling N. Auer A. A. Cornella J. Angew. Chem., Int. Ed. 2023 e202313578
(k) Tsuruta T. Spinnato D. Moon H. W. Leutzsch M. Cornella J. J. Am. Chem. Soc. 2023 145 25538 10.1021/jacs.3c10333 37963280
Mato M. Spinnato D. Leutzsch M. Moon H. W. Reijerse E. J. Cornella J. Nat. Chem. 2023 15 1138 1145 10.1038/s41557-023-01229-7 37264103
Planas O. Peciukenas V. Cornella J. J. Am. Chem. Soc. 2020 142 11382 10.1021/jacs.0c05343 32536157
Planas O. Peciukenas V. Leutzsch M. Nöthling N. Pantazis D. A. Cornella J. J. Am. Chem. Soc. 2022 144 14489 10.1021/jacs.2c01072 35921250
(a) Chitnis S. S. Burford N. Decken A. Ferguson M. J. Inorg. Chem. 2013 52 7242 10.1021/ic400875a 23718560
(b) Chitnis S. S. Robertson A. P. M. Burford N. Patrick B. O. McDonald R. Ferguson M. J. Chem. Sci. 2015 6 6545 10.1039/C5SC02423D 30090272
(c) Chitnis S. S. Vos K. A. Burford N. McDonald R. Ferguson M. J. Chem. Commun. 2016 52 685 10.1039/C5CC08086J 26569099
(d) Hynes T. Masuda J. D. Chitnis S. S. ChemPlusChem 2022 87 e202200244 10.1002/cplu.202200244 36166684
(e) Kindervater M. B. Hynes T. Marczenko K. M. Chitnis S. S. Dalton Trans. 2020 49 16072 10.1039/D0DT01413C 32469352
(f) Kindervater M. B. Marczenko K. M. Werner-Zwanziger U. Chitnis S. S. Angew. Chem., Int. Ed. 2019 58 7850 10.1002/anie.201903354 30945403
(g) Marczenko K. M. Chitnis S. S. Chem. Commun. 2020 56 8015 10.1039/D0CC00254B 32026911
(h) Marczenko K. M. Zurakowski J. A. Kindervater M. B. Jee S. Hynes T. Roberts N. Park S. Werner-Zwanziger U. Lumsden M. Langelaan D. N. Chitnis S. S. Chem. - Eur. J. 2019 25 16414 10.1002/chem.201904361 31574185
(i) Marczenko K. M. Jee S. Chitnis S. S. Organometallics 2020 39 4287 10.1021/acs.organomet.0c00378
Hannah T. J. McCarvell W. M. Kirsch T. Bedard J. Hynes T. Mayho J. Bamford K. L. Vos C. W. Kozak C. M. George T. Masuda J. D. Chitnis S. S. Chem. Sci. 2023 14 4549 10.1039/D3SC00917C 37152250
Lu W. Hu H. Li Y. Ganguly R. Kinjo R. J. Am. Chem. Soc. 2016 138 6650 10.1021/jacs.6b03432 27135617
Dange D. Davey A. Abdalla J. A. B. Aldridge S. Jones C. Chem. Commun. 2015 51 7128 10.1039/C5CC01772F 25811397
(a) Dunaj T. Dollberg K. von Hänisch C. Dalton Trans. 2022 51 7551 10.1039/D2DT00472K 35506874
(b) Dunaj T. Dollberg K. Ritter C. Dankert F. Hänisch C. Eur. J. Inorg. Chem. 2021 2021 870 10.1002/ejic.202001019
(c) Dunaj T. Egorycheva M. Arebi A. Dollberg K. von Hänisch C. Z. Anorg. Allg. Chem. 2023 649
(d) Dunaj T. von Hänisch C. Chem.–Eur. J. 2022 28 e202202932 10.1002/chem.202202932 36409832
(e) Ritter C. Michel N. Rinow A. Ringler B. Hänisch C. Eur. J. Inorg. Chem. 2021 2021 2514 10.1002/ejic.202100303
(f) Ritter C. Weigend F. von Hänisch C. Chem.–Eur. J. 2020 26 8536 10.1002/chem.202002279 32428313
Dunaj T. Schwarzmann J. Ramler J. Stoy A. Reith S. Nitzsche J. Völlinger L. von Hänisch C. Lichtenberg C. Chem.–Eur. J. 2023 29 e202204012 10.1002/chem.202204012 36883595
(a) Ganesamoorthy C. Bläser D. Wölper C. Schulz S. Chem. Commun. 2014 50 12382 10.1039/C4CC05028B 25187200
(b) Tuscher L. Helling C. Wölper C. Frank W. Nizovtsev A. S. Schulz S. Chem.–Eur. J. 2018 24 3241 10.1002/chem.201705233 29266416
Prabusankar G. Gemel C. Parameswaran P. Flener C. Frenking G. Fischer R. A. Angew. Chem., Int. Ed. 2009 48 5526 10.1002/anie.200902172 19554586
Schneider S. von Hänisch C. Chem. Commun. 2022 58 1522 10.1039/D1CC06741A 35014997
Anker M. D. O'Reilly A. McMullin C. L. Coles M. P. Polyhedron 2023 246 116695 10.1016/j.poly.2023.116695
(a) Marquardt C. Hegen O. Vogel A. Stauber A. Bodensteiner M. Timoshkin A. Y. Scheer M. Chem. - Eur. J. 2018 24 360 10.1002/chem.201705510 29166549
(b) Bodensteiner M. Timoshkin A. Y. Peresypkina E. V. Vogel U. Scheer M. Chem.–Eur. J. 2013 19 957 10.1002/chem.201203074 23180654
(c) Bodensteiner M. Vogel U. Timoshkin A. Y. Scheer M. Angew. Chem., Int. Ed. 2009 48 4629 10.1002/anie.200901064 19449350
(d) Marquardt C. Jurca T. Schwan K.-C. Stauber A. Virovets A. V. Whittell G. R. Manners I. Scheer M. Angew. Chem., Int. Ed. 2015 54 13782 10.1002/anie.201507084 26427911
(e) Thoms C. Marquardt C. Timoshkin A. Y. Bodensteiner M. Scheer M. Angew. Chem., Int. Ed. 2013 52 5150 10.1002/anie.201209703 23576333
(f) Braese J. Lehnfeld F. Annibale V. T. Oswald T. Beckhaus R. Manners I. Scheer M. Chem. Eur. J. 2023 29 e202301741 10.1002/chem.202301741 37498679
(a) Szlosek R. Seidl M. Balázs G. Scheer M. Chem.–Eur. J. 2023 29 e202301752 10.1002/chem.202301752 37401824
(b) Hegen O. Virovets A. V. Timoshkin A. Y. Scheer M. Eur. J. Inorg. Chem. 2018 24 16521 16525
(c) Lehnfeld F. Seidl M. Timoshkin A. Y. Scheer M. Eur. J. Inorg. Chem. 2022 3 e202100930 10.1002/ejic.202100930
(d) Marquardt C. Kahoun T. Baumann J. Timoshkin A. Y. Scheer M. Z. Anorg. Allg. Chem. 2017 643 1326 10.1002/zaac.201700219
(e) Ackermann M. T. Seidl M. Wen F. Ferguson M. J. Timoshkin A. Y. Rivard E. Scheer M. Chem. - Eur. J. 2022 28 e20210370 10.1002/chem.202103780 34761837
(f) Marquardt C. Balázs G. Baumann J. Virovets A. V. Scheer M. Chem.–Eur. J. 2017 23 11423 10.1002/chem.201702384 28661010
(g) Marquardt C. Thoms C. Stauber A. Balázs G. Bodensteiner M. Scheer M. Angew. Chem., Int. Ed. 2014 53 3727 10.1002/anie.201310519 24591303
(h) Elsayed Moussa M. Kahoun T. Ackermann M. T. Seidl M. Bodensteiner M. Timoshkin A. Y. Scheer M. Organometallics 2022 41 1572 10.1021/acs.organomet.2c00194
(i) Marquardt C. Kahoun T. Stauber A. Balázs G. Bodensteiner M. Timoshkin A. Y. Scheer M. Angew. Chem., Int. Ed. 2016 55 14828 10.1002/anie.201608875 27778442
(j) Marquardt C. Hegen O. Kahoun T. Scheer M. Chem.–Eur. J. 2017 23 4397 10.1002/chem.201605625 28118508
(k) Vogel U. Timoshkin A. Y. Scheer M. Angew. Chem., Int. Ed. 2001 40 4409 10.1002/1521-3773(20011203)40:23<4409::AID-ANIE4409>3.0.CO;2-F
(l) Vogel U. Hoemensch P. Schwan K.-C. Timoshkin A. Y. Scheer M. Chem.–Eur. J. 2003 9 515 10.1002/chem.200390054 12532301
(m) Lehnfeld F. Seidl M. Timoshkin A. Y. Scheer M. Eur. J. Inorg. Chem. 2022 3 e202100930 10.1002/ejic.202100930
(n) Adolf A. Zabel M. Scheer M. Eur. J. Inorg. Chem. 2007 2007 2136 10.1002/ejic.200601186
(o) Lehnfeld F. Seidl M. Timoshkin A. Scheer M. Eur. J. Inorg. Chem. 2023 26 e202300338 10.1002/ejic.202300338
(p) Szlosek R. Niefanger A. S. Balázs G. Seidl M. Timoshkin A. Y. Scheer M. Chem.–Eur. J. 2024 30 e202303603 10.1002/chem.202303603 38131435
(a) Besson A. C. R. 1890 516
(b) Elsayed Moussa M. Braese J. Marquardt C. Seidl M. Scheer M. Eur. J. Inorg. Chem. 2020 26 2501 10.1002/ejic.202000330
(c) Elsayed Moussa M. Marquardt C. Hegen O. Seidl M. Scheer M. New J. Chem. 2021 45 14916 10.1039/D0NJ01679A
(d) Schwan K.-C. Adolf A. Bodensteiner M. Zabel M. Scheer M. Z. Anorg. Allg. Chem. 2008 634 1383 10.1002/zaac.200800079
(e) Szlosek R. Ackermann M. T. Marquardt C. Seidl M. Timoshkin A. Y. Scheer M. Chem.–Eur. J. 2023 29 e202202911 10.1002/chem.202202911 36259382
Braese J. Schinabeck A. Bodensteiner M. Yersin H. Timoshkin A. Y. Scheer M. Chem.–Eur. J. 2018 24 10073 10.1002/chem.201802682 29845655
(a) Schwan K.-C. Timoshkin A. Y. Zabel M. Scheer M. Chem.–Eur. J. 2006 12 4900 10.1002/chem.200600185 16642534
(b) Marquardt C. Hegen O. Hautmann M. Balázs G. Bodensteiner M. Virovets A. V. Timoshkin A. Y. Scheer M. Angew. Chem., Int. Ed. 2015 54 13122 10.1002/anie.201505773 26337399
Marquardt C. Adolf A. Stauber A. Bodensteiner M. Virovets A. V. Timoshkin A. Y. Scheer M. Chem. - Eur. J. 2013 19 11887 10.1002/chem.201302110 23907931
Weinhart M. A. K. Lisovenko A. S. Timoshkin A. Y. Scheer M. Angew. Chem., Int. Ed. 2020 59 5541 10.1002/anie.201914046 31815355
Weinhart M. A. K. Seidl M. Timoshkin A. Y. Scheer M. Angew. Chem. 2021 133 3850 10.1002/ange.202013849
Szlosek R. Weinhart M. A. K. Balázs G. Seidl M. Zimmermann L. Scheer M. Chem.–Eur. J. 2023 29 e202300340 10.1002/chem.202300340 36809680
Dollberg K. Marx A. Richter R.-M. Erlemeier L. Dunaj T. Weigend F. von Hänisch C. Chem.–Eur. J. 2024 30 e202303734 10.1002/chem.202303734 38146961
