Axel Schulz

• Professor
• full professor at University of Rostock

The heavy bismuth, a metal, and the light nitrogen, a non-metal, both elements of the 15th group of the periodic table of the elements, do not occur in nature in a binary compound. In addition to sulfidic and oxidic bismuth ores, there is even elemental bismuth in nature, but no natural bismuth–nitrogen compounds, so it is not surprising that bismu...

The linkage of an imidazole‐based N‐heterocyclic olefin (NHO), containing a terminal CH2 donor group, with a phosphorus‐centered diradical molecular fragment leads to an open‐shell singlet diphospha‐indenylide system, a new class of P‐heterocycles, which can be interpreted both as a phosphorus‐centered diradicaloid and as a zwitterion with a perman...

The linkage of an imidazole‐based N‐heterocyclic olefin (NHO), containing a terminal CH2 donor group, with a phosphorus‐centered diradical molecular fragment leads to an open‐shell singlet diphospha‐indenylide system, a new class of P‐heterocycles, which can be interpreted both as a phosphorus‐centered diradicaloid and as a zwitterion with a perman...

A Zr( iv ) triazenido hydride complex is formed by reaction of an alkyne complex with diphenyltriazene and activates CO 2 , forming a Zr( iv ) formate. Transfer of the hydrogen from the triazene to the alkyne is suggested to occur mediated by pyridine.

The Staudinger reaction provides chemists with a valuable tool for the reduction of azides, which are notoriously unstable and can decompose explosively. By providing a controlled method for the conversion of azides to amines, the reaction opened up new avenues for the synthesis of various amine‐containing compounds that are widely used in natural...

A new molecular switch is presented that combines both biradical and azobenzene motifs to perform visible light-induced constitutional and stereo-isomerisation within the same molecule. The insertion of isonitrile-functionalised azobenzenes into the four-membered biradical [˙P(μ-NTer)2P˙] (1), yielding a phosphorus-centred cyclopentane-1,3-diyl (E-...

Pseudohalides such as tricyanomethanide, [C(CN)3]⁻, are well known in chemistry, biochemistry and industrial chemistry. The protonated species HC(CN)3, a classic hydrogen pseudohalide Brønsted acid, is a very strong acid with a pKa value of −5. However, HC(CN)3 is difficult to handle as it tends to decompose rapidly or, more precisely, to oligo‐ an...

Biradicals are important intermediates in the formation and breaking of a chemical bond. Their use as molecular switches is of particular interest. Much less is known about tetraradicals, which can, for example, consist of two biradical(oid) units. Here we report the synthesis of the first persistent phosphorus‐centred tetraradical bound to a trans...

Pseudohalides such as tricyanomethanide, [C(CN)3]−, are well known in chemistry, biochemistry and industrial chemistry. The protonated species HC(CN)3, a classic hydrogen pseudohalide Brønsted acid, is a very strong acid with a pKa value of −5. However, HC(CN)3 is difficult to handle as it tends to decompose rapidly or, more precisely, to oligo‐ an...

This study delves into the acid modification of natural zeolite clinoptilolite, focusing on the identification of acid site types and their catalytic activity in the Brønsted acid‐catalyzed acetalization of benzaldehyde with 1,3‐butanediol. Following calcination, the samples underwent acidification via ammonium‐ion exchange, resulting in approximat...

2‐(1‐Hydroxyethylidene)malononitrile (4) is commercially sold as the keto isomer and is described in the literature as either a keto (4 b) or enol (4 a) species. Using NMR techniques and single crystal X‐ray diffraction, we were able to show that 4 exists exclusively as the enol isomer (4 a) in solution as well as in the solid state, which agrees w...

Reactions of a masked N‐heterocyclic phosphinidene (mNHP, 1), a four‐membered heterocycle with a divalent P atom, with various isonitriles (tBu−NC, Dmp−NC) and carbonyls (CO, Fe(CO)5, and benzalacetone) have been studied. The isonitriles (tBu−NC and Dmp−NC) insert into a P−N bond of the four‐membered ring of 1, leading to the formation of a five‐me...

Phosphorus‐centered disbiradicals, in which the radical sites exist as individual spin doublets with weak spin‐spin interaction have not been known so far. Starting from monoradicals of the type [⋅P(μ‐NTer)2P−R], we have now succeeded in linking two such monoradical phosphorus centers by appropriate choice of a linker. To this end, biradical [⋅P(μ‐...

Phosphorus‐centered disbiradicals, in which the radical sites exist as individual spin doublets with weak spin‐spin interaction have not been known so far. Starting from monoradicals of the type [•P(μ‐NTer)2P–R], we have now succeeded in linking two such monoradical phosphorus centers by appropriate choice of a linker. To this end, biradical [•P(μ‑...

Heteroatom-centered diradical(oid)s have been in the focus of molecular main group chemistry for nearly 30 years. During this time, the diradical concept has evolved and the focus has shifted to the rational design of diradical(oid)s for specific applications. This review article begins with some important theoretical considerations of the diradica...

The artwork shows a phosphorus-centered tetraradical wrapped in a streamline plot of current density susceptibility. A stellar hydrogen nebula can be seen in the background, as the tetraradical is able to activate hydrogen stepwise. Article: https://doi.org/10.1021/jacs.3c03928

Biradicals are important intermediates in the process of bond formation and breaking. While main-group-element-centered biradicals have been thoroughly studied, much less is known about tetraradicals, as their very low stability has hampered their isolation and use in small-molecule activation. Herein, we describe the search for persistent phosphor...

The synthesis of sterically demanding 2,6-bis(2,4,6-trimethylphenyl)phenyl (Ter)-stabilized and H-substituted diphosphanes TerHP-PR2 (4a-4c) via conversion of the phosphide TerPHK (2) with secondary chlorophosphanes ClPR2 (3a-3c, where R = iPr, Ph, and tBu, respectively) is described. The diphosphanes 4a-4c were deprotonated using KH in tetrahydrof...

The chlorination of 1,2‐diphosphinobenzene with PCl5 to 1,2‐bis(dichlorophosphino)benzene was performed with high yields (93 %) despite the high number of P−H functions. The method was further applied to other phosphanes, enabling the first synthesis and complete characterization of 1,2,4‐tris(dichlorophosphino)benzene (89 % yield) and 1,2,4,5‐tetr...

Differently substituted phenyl isonitriles (with C−H bonds in ortho‐position) and naphthyl isonitriles were reacted with the cyclic biradical [⋅P(μ‐N‐Ter)2P⋅] (1). Insertion of the isonitrile formed a cyclic five‐membered biradical [⋅P(NTer)2C(R)P⋅] (2R, R=phenyl, naphthyl) in the first step, followed by C−H activation at the aryl substituent, resu...

In solution, the Pacman chlorophosphane (2Cl) shows fast exchange of the endo/exo-orientation of the two P-Cl bonds in the molecule featuring cooperativity. Experimental and quantum mechanical investigations of the inversion on the phosphorus(III) centers reveal a crucial role of chloride ions in the dynamic process. To confirm the results, the hom...

We present the extension of Pacman ligands to bidentate phosphane ligands enabling them to bind metals in their sterically protected cavity. The coordination of coinage metals shows the ability of...

Natural microporous clinoptilolite zeolite-CLIN was acidified via ammonium ion exchange (0.5 M NH4NO3, 80°C, 1 h) followed by calcination (300-600°C) and HCl treatment (0.1-2M, 80°C, 1h) under soft conditions, i.e. low temperature, acid concentration, short treatment time, and moderate post thermal treatment. The influence of the modification type...

The biradical [·P(µ‐N‐ t BuPh3C)2P·] (6T) can be generated by reduction of a cyclic dichlorophosphane, [ClP(µ‐N‐ t BuPh3C)2PCl], utili­zing magnesium. If this biradical is treated with alkynes, e.g. tolan, Ph‐C ºC‐Ph, the addition product, a [2.1.1.] bicyclic species, [P(µ‐N‐ t BuPh3C)2P(Ph‐C=C‐Ph)] (7), is obtained. However, if the reduction proce...

Electrophilic aromatic substitution (EAS) can provide a straightforward approach to the efficient synthesis of functionalized complex aromatic molecules. In general, Lewis acids serve as a beneficial stimulus for the formation of a Wheland complex, the intermediate in the classical SEAr mechanism of EAS, which is responsible for H/E (E=electrophile...

Homoleptic cyanide compounds exist of almost all main group elements. While the alkali metals and alkaline earth metals form cyanide salts, the cyanides of the lighter main group elements occur mainly as covalent compounds. This review gives an overview of the status quo of main group element cyanides and cyanido complexes. Information about synthe...

The reaction of the singlet biradical [P(μ-NTer)]2 with various aldehydes selectively yielded the corresponding [2.1.1]-bicyclic addition products in a very fast reaction. All products were fully characterized, including by NMR and vibrational spectroscopy as well as single-crystal X-ray diffraction. The mechanism of the addition was investigated t...

The reaction of a lithiated supermesityl‐substituted amino‐diphosphene with boron trichloride yielded a formal 2‐aza‐3,4‐diphospha‐1‐bora‐heterobutadiene after LiCl elimination. X‐ray structure and bonding analyses revealed a planar trans‐bent B‐N‐P‐P framework with short B‐N and P‐P bond lengths in accord with the description as a heterobutadiene...

The activation of C−Br bonds in various bromoalkanes by the biradical [⋅P(μ‐NTer)2P⋅] (1) (Ter=2,6‐bis‐(2,4,6‐trimethylphenyl)‐phenyl) is reported, yielding trans‐addition products of the type [Br−P(μ‐NTer)2P−R] (2), so‐called 1,3‐substituted cyclo‐1,3‐diphospha‐2,4‐diazanes. This addition reaction, which represents a new easy approach to asymmetri...

The oxidation of silylated hydrazine, (Me3Si)2N−N(H)SiMe3, with silver salts led to the formation of a highly labile hydrazinium‐yl radical cation, [(Me3Si)2N−N(H)SiMe3].+, at very low temperatures (decomposition > −40 °C). EPR, NMR, DFT and Raman studies revealed the formation of a nitrogen‐centered radical cation along the N−N unit of the hydrazi...

The reaction between [Ru 2 Cl 2 ( μ 2 ‐Cl) 2 (CO) 6 ] and the biradicaloid [P( μ ‐NTer)] 2 proceeds under insertion of a Ru(II)Cl(CO) 2 fragment into one P−N bond and addition of chloride to the adjacent phosphorus center. Thereby an unprecedented inorganic ruthenacycle is obtained that was investigated by single crystal X‐ray analysis, NMR and IR...

Heterocyclobutane-1,3-diyls bridge the gap between organic and inorganic chemistry and are known for the majority of group 13–15 elements. The kinetically stabilized compounds have been employed in the activation of small molecules, akin to conventional transition metal complexes, and are thus cost-efficient alternatives for future processes. Here,...

Natural zeolite clinoptilolite CLIN with a framework ratio of Si/Al ≥ 4 containing mainly potassium and calcium ions in its internal channel system was used as a starting material. The acidic HCLIN catalysts were prepared under soft conditions avoiding the use of environmental less-benign mineral acids. The starting material was ion exchanged using...

Alkali metal salts, M⁺[Ter(iPr)P−C(=S)−P(iPr)2S].− (M=Na, K; 2_M; Ter=2,6‐bis‐(2,4,6‐trimethylphenyl)phenyl) containing a room‐temperature‐stable thioketyl radical anion were obtained by reduction of the thioketone precursor, Ter(iPr)P−C(=S)−P(iPr)2S (1), with alkali metals (Na, K). Single‐crystal X‐ray studies as well as EPR spectroscopy revealed...

The reaction of the biradical [( m -NTer)P · ] 2 ( 1 ) with thiophosgene, SCCl 2 , leads to a cyclic phospha-aza thiourea derivative ( 7 ) in very good yields. This synthetic approach represents a new possibility to...

Starting from the fundamental organometallic research work of Franz Hein, Erhard Kurras investigated the possibility of isolating stable organochromium compounds. He studied the existence of σ‐alkyl and σ‐alkylene complexes, π‐allyl compounds, as well as dichromium complexes containing a chromium‐chromium quadruple bond. Since that time a variety o...

Alkali metal salts, M + [Ter( i Pr)P-C(=S)-P( i Pr) 2 S] •− (M = Na, K; 2_M; Ter = 2,6-bis-(2,4,6-trimethyl-phenyl)-phenyl) containing a room-temperature-stable thioketyl radical anion were obtained by reduction of the thioketone precursor, Ter( i Pr)P-C(=S)-P( i Pr) 2 S ( 1 ), with alkali metals (Na, K). Single crystal X-ray studies as well as EPR...

Formal coordination of phosphorus(III) by a calix[4]pyrrole Schiff base ligand was achieved through the reaction of this ligand with PCl3 under basic conditions. The reaction product adopts a Pacman conformation with two P−Cl moieties, one in exo and one in endo position. It represents the first non‐metal compound of calix[4]pyrrole Schiff base lig...

The reactivity of the secondary phosphide KP(iPr)Ter (1) (Ter = 2,6-bis-(2,4,6-trimethylphenyl)phenyl) toward small molecules is reported. Phosphide 1 displays distinct nucleophilic character and reacts selectively with chalcogens (S8, Sex), heteroallenes (CO2, nPrNCS), and an acyl chloride (AdCOCl) to give the corresponding dichalcogenophosphinate...

Three large pore crystalline zirconium-based metal-organic frameworks (Zr-MOFs) of different pore sizes (6–18 Å) and structure were synthesized and used for the preparation of the Rh-supported catalysts [email protected], [email protected], and [email protected] The materials were characterized by XRD, FTIR, SEM/TEM, XPS, and nitrogen adsorption/de...

Context. Long-term deep brain stimulation (DBS) studies in rodents are of crucial importance for research progress in this field. However, most stimulation devices require jackets or large head-mounted systems which severely affect mobility and general welfare influencing animals’ behavior. Objective. To develop a preclinical neurostimulation impla...

The synthesis and reactivity of sterically demanding phosphaarsanes TerR1P-AsR2 (3) is described. These species were selectively synthesized via metathesis reactions of Ter-stabilized [Ter = 2,6-bis(2,4,6-trimethylphenyl)phenyl] potassium phosphides TerR1PK (1) with the N-heterocyclic chloroarsane ClAs{N(tBu)CH2}2 (2). Conversion of the n-butyl-sub...

The chemistry of silylated sulfuric acid, O2S(OSiMe3)2 (T2SO4, T=Me3Si; also known as bis(trimethylsilyl) sulfate), has been studied in detail with the aim of synthesizing the formal autosilylation products of silylated sulfuric acid, [T3SO4]⁺ and [TSO4]⁻, in analogy to the known protonated species, [H3SO4]⁺ and [HSO4]⁻. The synthesis of the [TSO4]...

1,1‐ or 1,3‐product, that is the question: When Me3Si−Psh (Psh=pseudohalogen=CN, N3, OCN, and SCN) is treated with Lewis acids (LA) GaCl3 and B(C6F5)3, adducts such as Me3Si−Psh ⋅ GaCl3 and Me3Si−Psh ⋅ B(C6F5)3 are formed. Quantum mechanical calculations show that the thermodynamically favored product of the gas phase is not always observed, becaus...

The preparation of mesoporous silica supported zinc oxide photocatalyst (MS/ZnO) was carried out using the direct and indirect approaches (impregnation) in solvent media and grinding approach (mechanochemical) in a solvent-free media. This showed the dissemination of zinc oxide nanoparticles over mesoporous substrates that associated with the forma...

This review summarises the experimental and structural knowledge on polycyclic phosphanes, with a focus on bicyclic and tricyclic phosphanes, as they have not only been the most studied in the last 25 years, but also show the greatest diversity in terms of constitutional isomerism and structural motifs. Moreover, only polycyclic phosphanes that hav...

Biradicaloids attract attention as a novel class of reagents that can activate small molecules such as H2, ethylene and CO2. Herein, we study activation of parahydrogen (nuclear spin‐0 isomer of H2) by a number of 4‐ and 5‐membered pnictogen biradicaloids based on hetero‐cyclobutanediyl [X(μ‐NTer)2Z] and hetero‐cyclopentanediyl [X(μ‐NTer)2ZC(NDmp)]...

Das „größere“ Analogon der protonierten Schwefelsäure, [H3SO4]⁺, das silylierte Oxosulfoniumion, [(Me3Si)3SO4]⁺, wird in der Reaktion von silylierter Schwefelsäure mit einem [Me3Si]⁺-Transferreagenz wie [Me3Si-H-SiMe3]⁺[wca]⁻ erhalten, wenn ein schwach koordinierendes Anion ([wca]⁻) als Gegenion verwendet wird. Abstract Die Chemie der silylierten...

As previously reported, photoisomerization of the open-shell singlet biradicaloid [TerNP]2CNDmp (2) yields its closed-shell housane-type isomer (3). In the present study, pump-probe spectroscopy was applied to investigate the excited-state dynamics of the photoisomerization, indicating ultrafast de-excitation of the S1 state through a conical inter...

In this article, we review the concept of biradical(oid)s from a theoretical as well as experimental perspective. In particular, we analyze the “two electrons in two orbitals” model, which is frequently used to describe the electronic structure of biradical(oid)s, with special emphasis on systems with a small HOMO-LUMO gap, so-called open-shell sin...

Conversion of 1,2‐bis(dichlorophosphino)benzene with sterically demanding primary amines led to the formation of 1,3‐dichloro‐2‐aza‐1,3‐diphosphaindanes of the type C6H4(μ‐PCl)2N‐R. Reduction yielded the corresponding 2‐aza‐1,3‐diphosphaindane‐1,3‐diyls (1), which can be described as phosphorus‐centered singlet biradical(oid)s. Their stability depe...

Within the second funding period of the SPP 1708 "Material Synthesis near Room Temperature",which started in 2017, we were able to synthesize novel anionic species utilizing Ionic Liquids (ILs) both, as reaction media and reactant. ILs, bearing the decomposable and non-innocent methyl carbonate anion [CO3 Me]- , served as starting material and enab...

Phosphorus centered biradicaloids of the type [P(μ‐NTer)]2 [R = Ter = terphenyl = 2,6‐bis(2,4,6‐trimethylphenyl)phenyl, Hyp = tris(trimethylsilyl)silyl] were treated with covalent (R‐N3) and ionic azides (AgN3 and Hg(N3)2). While the reaction with the ionic azides led exclusively to the formation of diazides, [N3P(μ‐NTer)]2, triaza‐diphospha‐pentad...

Lediglich ein einziger sehr sperriger Substituent R ist erforderlich, um die ersten stabilen Heteroidandiyle zu stabilisieren (siehe Bild), die eine Gruppe resonanzstabilisierter phosphorzentrierter Biradikale darstellen. Bei kleineren Substituenten wurden verschiedene Arten von Oligomeren beobachtet, die durch Selbstaktivierung des aromatischen Rü...

The trapping of classical hydrogen pseudohalides (HX, X = pseudohalogen = CN, N3, NCO, NCS, and PCO) utilizing a phosphorus-centered cyclic biradicaloid, [P(μ-NTer)]2, is reported. These formal Brønsted acids were generated in situ as gases and passed over the trapping reagent, the biradicaloid [P(μ-NTer)]2, leading to the formation of the addition...

In the presence of μ-nitridobis(triphenylphosphonium) cation, [PPN]+, it was possible to stabilize and isolate [PPN]+-salts bearing the highly labile hydrogen cyanide aggregate anions of pseudohalides X (X = N3, OCN and SCN). From a concentrated solution of the [PPN]X salts in HCN, crystals of [PPN][X(HCN)3] (X = N3, OCN) or [PPN][SCN(HCN)2] could...

Sterically demanding secondary potassium phosphides (4) were synthesized and investigated. Reaction with halophosphanes (5) yields diphosphanes (6), whereas reaction with CS2 yields phosphanyl dithioformates (10). These can be further converted to the corresponding phosphanyl esters of dithioformic acid R2P-C(S)S-PR2 (8). One of these thioesters (8...

The photo-isomerization of an isolable five-membered singlet biradical based on C, N, and P ([TerNP]2CNDmp, 2a) selectively afforded a closed-shell housane-type isomer (3a) by forming a transannular P-P bond. In the dark, the housane-type species re-isomerized to the biradical, resulting in a fully reversible overall process. In the present study,...

Functionalized imidazolium cations were combined with the hexacyanidosilicate anion, [Si(CN)6]2–, by salt metathesis reactions with K2[Si(CN)6], yielding novel ionic compounds of the general formula [R–Ph(nBu)Im]2[Si(CN)6] {R = 2‐Me (1), 4‐Me (2), 2,4,6‐Me = Mes (3), 2‐MeO (4), 2,4‐F (5), 4‐Br (6); Im = imidazolium}. All synthesized imidazolium hex...

The reaction of the singlet biradical [P(μ NHyp)]2 (Hyp = hypersilyl, (Me3Si)3Si) with different isonitriles afforded a series of five-membered N2P2C heterocycles. Depending on the steric bulk of the substituent at the isonitrile, migration of a Hyp group was observed, resulting in two structurally similar, but electronically very different isomers...

Although pure hydrogen cyanide can spontaneously polymerize or even explode, when initiated by small amounts of bases (e.g. CN⁻), the reaction of liquid HCN with [WCC]CN (WCC=weakly coordinating cation=Ph4P, Ph3PNPPh3=PNP) was investigated. Depending on the cation, it was possible to extract salts containing the formal dihydrogen tricyanide [CN(HCN...

Flexible Cyanide. Sperrige Kationen und schnelle Kristallisation ermöglichten die Isolierung und strukturelle Charakterisierung von den HCN‐Cyanid‐Aggregat‐Vertretern [CN(HCN)2)]⁻ und [CN(HCN)3)]⁻ als Festkörper. Abstract Obwohl reiner Cyanwasserstoff spontan polymerisieren oder sogar explodieren kann, was durch geringe Mengen an Basen (z. B. CN⁻)...

Attempts have been made to prepare salts with the labile tris(trimethylsilyl)chalconium ions, [(Me3Si)3E]⁺ (E=O, S), by reacting [Me3Si‐H‐SiMe3][B(C6F5)4] and Me3Si[CB] (CB⁻=carborate=[CHB11H5Cl6]⁻, [CHB11Cl11]⁻) with Me3Si‐E‐SiMe3. In the reaction of Me3Si‐O‐SiMe3 with [Me3Si‐H‐SiMe3][B(C6F5)4], a ligand exchange was observed in the [Me3Si‐H‐SiMe3...

The reaction of TMP-NH2 [TMP = m,m-(CF3)2-C6H3] with 2 equiv of n-BuLi led to the in situ formation of Li2[N-TMP], which, after the addition of BiCl3, formed a [Cl-Bi(μ3-N-TMP)]4-type heterocubane in up to 30% yield. Transmetalation reactions, thought of as alternatives, starting from the analogous tin-nitrogen heterocubane [Sn(μ3-N-TMP)]4 and BiCl...

The reaction of biradical [P(μ‐NTer)]2 (1, Ter = 2,6‐bis(2,4,6‐trimethylphenyl)phenyl) towards different alkenes (R = 2,3‐dimethyl–butadiene, 2,5‐dimethyl‐2,4‐hexadiene, 1,7‐octadiene, 1,4‐cyclohexadiene) and alkynes (R = 1,4‐diphenyl‐1,3‐butadiyne) was studied experimentally. Although these olefins can react in different ways, only [2+2] cycloaddi...

The reactivity of the four‐membered NP3 ring system [RN(μ‐PCl)2PR] (R=Mes*=2,4,6‐tri‐tert‐butylphenyl) towards Lewis acids, Lewis bases, and reducing agents was investigated. Comparisons with the literature‐known, analogous cyclic compounds [ClP(μ‐NR)]2 (R=Ter=2,6‐dimesitylphenyl) and [ClP(μ‐PR)]2 (R=Mes*) are drawn, to obtain a better systematic u...

Correction for ‘Increasing steric demand through flexible bulk – primary phosphanes with 2,6-bis(benzhydryl)phenyl backbones’ by Jonas Bresien et al. , Dalton Trans. , 2019, 48 , 3786–3794.

The synthesis of Bbp stabilized biradicals of the type [E(µ-NBbp)]2 (E = P, As) (Bbp = 2,6-bis[bis(trimethylsilyl)methyl]-phenyl) was investigated. Contrary to the established synthetic protocol for terphenyl substituted biradicals [E(µ-NTer)]2 by reduction of [ClE(µ-NTer)]2, the analogous Bbp substituted precursor [ClE(µ-NBbp)]2 could only be obta...

Several pseudohalide containing ionic liquids with quarternary ammonium counter cations of the general formula [R3MeN]X [R = ethyl (1X), n‐butyl (2X) with X– = CN–, N3–, OCN–, and SCN–] were synthesized by decomposition of the corresponding trialkylammonium methylcarbonate in the reaction with Me3Si–X. We also treated 2CN with OP(OMe)3, yielding [n...

Triazenido metal complexes have been extensively investigated for more than a century, especially transition metal complexes. However, in each of the known examples for titanium, the oxidation state of the metal is +4. Therefore, we sought to prepare a complex containing titanium(III). To achieve this goal, triazenes RNNN(H)R′ (1R, with R = R′ = Ph...

The reaction of HN3 with the strong Lewis acid B(C6F5)3 led to the formation of a very labile HN3⋅B(C6F5)3 adduct, which decomposed to an aminoborane, H(C6F5)NB(C6F5)2, above −20 °C with release of molecular nitrogen and simultaneous migration of a C6F5 group from boron to the nitrogen atom. The intermediary formation of azide–borane adducts with B...

When [PPN]SCN (1; PPN = [Ph 3 P-N-PPh 3 ]) is treated with Me 3 Si-SCN in methanol, [PPN][H(NCS) 2 ] (2), a hydrogen diisothiocyanate salt bearing the [H(NCS) 2 ] ⁻ anion, was generated, isolated, and fully characterized. Pure heavy E(NCS) 3 [E = Sb (3), Bi (4)] species were obtained from the reaction of EF 3 and an excess of Me 3 Si-SCN, while the...

Metal-free H2 activations are unusual but interesting for catalytic transformations, particularly in parahydrogen-based nuclear spin hyperpolarization techniques. We demonstrate that metal-free singlet phosphorus biradicaloid, [P(μ-NTer)]2, provides pronounced 1H and 31P hyperpolarization while activating the parahydrogen molecules. A brief analysi...

The reaction of HN3 with the strong Lewis acid B(C6F5)3 led to the formation of a very labile HN3·B(C6F5)3 adduct, which decomposed to an aminoborane, H(C6F5)NB(C6F5)2, above –20°C with the release of molecular nitrogen and simultaneous migration of a C6F5 group from boron to nitrogen. Hydrolysis of the aminoborane provided C6F5‐substituted amine,...

Starting from fluoridosilicate precursors in neat cyanotrimethylsilane, Me3Si−CN, a series of different ammonium salts [R3NMe]⁺ (R=Et, ⁿPr, ⁿBu) with the novel [SiF(CN)5]²⁻ and [Si(CN)6]²⁻ dianions was synthesized in facile, temperature controlled F⁻/CN⁻ exchange reactions. Utilizing decomposable, non‐innocent cations, such as [R3NH]⁺, it was possi...

A facile synthesis and full characterization of a series of [Ag(arene) 3 ][B(C 6 F 5 ) 4 ] salts (arene = C 6 H 6 , MeC 6 H 5 , EtC 6 H 5 , i-PrC 6 H 5 , n-PrC 6 H 5, 1,2-Me 2 C 6 H 4 , 1,3-Me 2 C 6 H 4 , 1,4-Me 2 C 6 H 4 , 1,2,3-Me 3 C 6 H 3 , 1,2,4-Me 3 C 6 H 3 , 1,2,5-Me 3 C 6 H 3 , 1,2,3,5-Me 4 C 6 H 2 , 1,2,4,5-Me 4 C 6 H 2 , Me 5 C 6 H, Me 6...

Sterically demanding primary phosphanes of the type RBhp−PH2 (Bhp = 2,6-bis(benzhydryl)-4-R-phenyl; R = Me, tBu) could be prepared in high yields by modification of synthetic protocols of established bulky phosphanes. The Bhp substituents simultaneously exhibit extensive steric expansiveness and high degrees of flexibility compared to other 2,6-sub...

Starting from fluoridosilicate precursors in neat cyano‐trimethylsilane, Me3Si‐CN, a series of different ammonium salts [R3NMe]+ (R = Et, nPr, nBu) with the novel [SiF(CN)5]2− and [Si(CN)6]2− dianions were synthesized in facile, temperature controlled F− / CN− exchange reactions. Utilizing decomposable, non‐innocent cations such as [R3NH]+, it was...

Molecular switches are molecules that can reversibly be shifted between at least two stable states with different physical and chemical properties, making them interesting for application as chemical sensors or molecular machines. We recently discovered that five-membered, cyclic biradicals based on group 15 elements are efficient and robust photoc...

Mes*N(SiMe3)BiCl2 (1, Mes* = 2,4,6‐tri‐tert‐butylphenyl) can be referred to as a hidden iminobismuthane, Mes*N=BiCl, which was thought to be generated in‐situ upon Me3SiCl elimination triggered by a Lewis acid such as GaCl3. Therefore, the reactivity of aminobismuthane 1 was studied to find a synthesis route for the formation of a tetrazabismuthole...

Metal-free H 2 activations are unusual but interesting for catalytic transformations, particularly in parahydrogen-based nuclear spin hyperpolarization techniques. We demonstrate that metal-free singlet phosphorus biradicaloid, [P(µ-NTer)] 2 , provides pronounced ¹ H and ³¹ P...

Grignard Compounds In their Communication on page 716 ff., H. Schnöckel and co‐workers study the complex reduction process of bulk magnesium in the formation of Grignard compounds through reactions of metastable MgI halide solutions.