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Halogenated closo -dodecaborates are very robust and versatile weakly coordinating anions for numerous applications. The introduction of additional substituents, e.g., pseudohalides, allows the tuning of their chemical and physical properties. In this report, the synthesis of the isocyanate-substituted closo -dodecaborates [B 12 X 11 (NCO)] 2- (X = H, F-I) was investigated. In an attempt to synthesize the undecahalogenated derivatives, a selective and halogen-dependent reaction yielding boron clusters carrying the functional groups amidinium (-NHCHNMe 2 ) and formamide (-NHC(O)H) was discovered. The halogenated anions were fully characterized by vibrational and NMR spectroscopy, mass spectrometry, and X-ray diffraction. Salts of the formamide-substituted anion [B 12 X 11 (NHC(O)H)] 2- are surprisingly thermally stable in the condensed phase. In contrast, collision-induced dissociation in the gas phase reveals that the isolated dianion [B 12 X 11 (NHC(O)H)] 2- in the gas phase preferentially loses water, while the protonated form, which was generated from decomposition of the tetraalkylammonium counterion [B 12 X 11 (NHC(O)H)H] - , tends to lose carbon monoxide. Possible reaction mechanisms are discussed.

Gaseous fragment ions generated in mass spectrometers may be employed as "building blocks" for the synthesis of novel molecules on surfaces using ion soft-landing. A fundamental understanding of the reactivity of the fragment ions is required to control bond formation of deposited fragments in surface layers. The fragment ion [B 12 X 11 ] - (X = halogen) is formed by collision-induced dissociation (CID) from the precursor [B 12 X 12 ] 2- dianion. [B 12 X 11 ] - is highly reactive and ion soft-landing experiments have shown that this ion binds to the alkyl chains of organic molecules on surfaces. In this work we investigate whether specific modifications of the precursor ion affect the chemical properties of the fragment ions to such an extent that attachment to functional groups of organic molecules on surfaces occurs and binding of alkyl chains is prevented. Therefore, a halogen substituent was replaced by a thiocyanate substituent. CID of the precursor [B 12 I 11 (SCN)] 2- ion preferentially yields the fragment ion [B 12 I 8 S(CN)] - , which shows significantly altered reactivity compared to the fragment ions of [B 12 I 12 ] 2- . [B 12 I 8 S(CN)] - has a previously unknown structural element, wherein a sulfur atom bridges three boron atoms. Gas-phase reactions with different neutral reactants (cyclohexane, dimethyl sulfide, and dimethyl amine) accompanied by theoretical studies indicate that [B 12 I 8 S(CN)] - binds with higher selectivity to functional groups of organic molecules than fragment ions of [B 12 I 12 ] 2- ( e.g. , [B 12 I 11 ] - and [B 12 I 9 ] - ). These findings were further confirmed by ion soft-landing experiments, which showed that [B 12 I 8 S(CN)] - ions attacked ester groups of adipates and phthalates, whereas [B 12 I 11 ] - ions only bound to alkyl chains of the same reagents.

Mass spectrometry frequently reveals the existence of transient gas phase ions that have not been synthesized in solution or in bulk. These elusive ions are, therefore, often considered to be primarily of analytical value in fundamental gas phase studies. Here, we provide proof-of-concept that the products of ion-molecule reactions in mass spectrometers may be collected on surfaces to generate condensed matter and thus serve as building blocks to synthesize new compounds. The highly reactive fragment anion [B 12 Br 11 ] - was generated in a mass spectrometer and converted to [B 12 Br 11 N 2 ] - in the presence of molecular nitrogen followed by its mass-selection and soft-landing on surfaces. The molecular structure of [B 12 Br 11 N 2 ] - , which has not been synthetically obtained before, was confirmed by conventional methods of molecular analysis, including nuclear magnetic resonance and infrared spectroscopy. The [B 12 Br 11 N 2 ] - ion is stable on surfaces and in solution at room temperature, but thermal annealing induces elimination of N 2 and provides access to the highly reactive intermediate [B 12 Br 11 ] - in the condensed phase, which can be further used as a reagent, for example, for electrophilic aromatic substitutions. Thus, isolation of [B 12 Br 11 N 2 ] - expands the repertoire of the available diazo ions that can be employed as versatile intermediates in various chemical transformations., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

A series of {V 12 }-nuclearity polyoxovanadate cages covalently functionalized with one or sandwiched by two phthalocyaninato (Pc) lanthanide (Ln) moieties via V-O-Ln bonds were prepared and fully characterized for paramagnetic Ln = Sm III -Er III and diamagnetic Ln = Lu III , including Y III . The LnPc-functionalized {V 12 O 32 } cages with fully oxidized vanadium centers in the ground state were isolated as ( n Bu 4 N) 3 [HV 12 O 32 Cl(LnPc)] and ( n Bu 4 N) 2 [HV 12 O 32 Cl(LnPc) 2 ] compounds. As corroborated by a combined experimental (EPR, DC and AC SQUID, laser photolysis transient absorption spectroscopy, and electrochemistry) and computational (DFT, MD, and model Hamiltonian approach) methods, the compounds feature intra- and intermolecular electron transfer that is responsible for a partial reduction at V(3d) centers from V V to V IV in the solid state and at high sample concentrations. The effects are generally Ln dependent and are clearly demonstrated for the ( n Bu 4 N) 3 [HV 12 O 32 Cl(LnPc)] representative with Ln = Lu III or Dy III . Intramolecular charge transfer takes place for Ln = Lu III and occurs from a Pc ligand via the Ln center to the {V 12 O 32 } core of the same molecule, whereas for Ln = Dy III , only intermolecular charge transfer is allowed, which is realized from Pc in one molecule to the {V 12 O 32 } core of another molecule usually via the n Bu 4 N + countercation. For all Ln but Dy III , two of these phenomena may be present in different proportions. Besides, it is demonstrated that ( n Bu 4 N) 3 [HV 12 O 32 Cl(DyPc)] is a field-induced single molecule magnet with a maximal relaxation time of the order 10 -3 s. The obtained results open up the way to further exploration and fine-tuning of these three modular molecular nanocomposites regarding tailoring and control of their Ln-dependent charge-separated states (induced by intramolecular transfer) and relaxation dynamics as well as of electron hopping between molecules. This should enable us to realize ultra-sensitive polyoxometalate powered quasi-superconductors, sensors, and data storage/processing materials for quantum technologies and neuromorphic computing.

We investigate collision-induced dissociation (CID) of [Mo 6 X 14 ] 2- (X = Cl, Br, I) and the reactivity of fragment ions of these precursors with background gases. Ion mobility measurements and theoretical calculations provide structural information for some of the observed ions. Sequential losses of MoX 2 units dominate the dissociation pathways of [Mo 6 Cl 14 ] 2- . Meanwhile, loss of X radicals is the main channel for X = Br and I. Ion mobility measurements and computational investigations indicate minor structural changes in the octahedral Mo 6 unit for [Mo 6 I m ] - ( m = 6-13) fragments. We observe that mass spectra obtained using CID substantially vary among mass spectrometers: Specifically, ions with molecular formula [Mo 6 X m (O 2 ) n ] - (X = Br and I) are observed as dominant species produced through reactions with O 2 in several mass spectrometers, but also adduct free fragment ions were observed in other instruments, depending on the background conditions. Ion-trap fragmentation combined with theoretical investigations indicates that spontaneous losses of X radicals occur upon binding of O 2 to [Mo 6 I m ] - fragments ( m ≤ 12). Theoretical investigations indicate that both oxygen atoms are bound to the vacant sites of the Mo 6 units. This study opens up a new vista to generate and study a large variety of hexanuclear Mo 6 X m (O 2 ) n anions.

The controlled adsorption of polynuclear coordination compounds with specific structural and electronic characteristics on surfaces is crucial for the prospective implementation of molecule-surface interfaces into practical electronic devices. From this perspective, a neutral 3d,4f-coordination cluster [Mn II 3 Mn IV Yb 3 O 3 (OH)(L·SMe) 3 (OOCMe) 9 ]·2MeCN·3EtOH ( 1 ·2MeCN·3EtOH), where L·SMe - is a Schiff base, has been synthesized and fully characterized and its adsorption on two different solid substrates, gold and graphite, has been studied. The mixed-valence compound with a bilayered metal core structure and the structurally exposed thioether groups exhibits a substantially different surface bonding to metallic gold and semimetallic graphite substrates. While on graphite the adsorption takes place only on distinguished attraction points with a locally increased number of potential bonding sites such as terrace edges and other surface defects, on gold the molecules were found to adsorb rather weakly on randomly distributed adsorption sites of the surface terraces. This entirely different behavior provides important information for the development of advanced surface materials that may enable well-distributed ordered molecular assemblies.

Nitro-functionalized undecahalogenated closo-dodecaborates [B 12 X 11 (NO 2 )] 2- were synthesized in high purities and characterized by NMR, IR, and Raman spectroscopy, single crystal X-diffraction, mass spectrometry, and gas-phase ion vibrational spectroscopy. The NO 2 substituent leads to an enhanced electronic and electrochemical stability compared to the parent perhalogenated [B 12 X 12 ] 2- (X=F-I) dianions evidenced by photoelectron spectroscopy, cyclic voltammetry, and quantum-chemical calculations. The stabilizing effect decreases from X=F to X=I. Thermogravimetric measurements of the salts indicate the loss of the nitric oxide radical (NO . ). The homolytic NO . elimination from the dianion under very soft collisional excitation in gas-phase ion experiments results in the formation of the radical [B 12 X 11 O] 2-. . Theoretical investigations suggest that the loss of NO . proceeds via the rearrangement product [B 12 X 11 (ONO)] 2- . The O-bonded nitrosooxy structure is thermodynamically more stable than the N-bonded nitro structure and its formation by radical recombination of [B 12 X 11 O] 2-. and NO . is demonstrated., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Focused electron beam induced deposition (FEBID) is a versatile tool for the direct-write fabrication of nanostructures on surfaces. However, FEBID nanostructures are usually highly contaminated by carbon originating from the precursor used in the process. Recently, it was shown that platinum nanostructures produced by FEBID can be efficiently purified by electron irradiation in the presence of water. If such processes can be transferred to FEBID deposits produced from other carbon-containing precursors, a new general approach to the generation of pure metallic nanostructures could be implemented. Therefore this study aims to understand the chemical reactions that are fundamental to the water-assisted purification of platinum FEBID deposits generated from trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtMe 3 ). The experiments performed under ultrahigh vacuum conditions apply a combination of different desorption experiments coupled with mass spectrometry to analyse reaction products. Electron-stimulated desorption monitors species that leave the surface during electron exposure while post-irradiation thermal desorption spectrometry reveals products that evolve during subsequent thermal treatment. In addition, desorption of volatile products was also observed when a deposit produced by electron exposure was subsequently brought into contact with water. The results distinguish between contributions of thermal chemistry, direct chemistry between water and the deposit, and electron-induced reactions that all contribute to the purification process. We discuss reaction kinetics for the main volatile products CO and CH 4 to obtain mechanistic information. The results provide novel insights into the chemistry that occurs during purification of FEBID nanostructures with implications also for the stability of the carbonaceous matrix of nanogranular FEBID materials under humid conditions.