@article{SperlichKoeckerling2023,
  author    = {Sperlich, Eric and K{\"o}ckerling, Martin},
  title     = {The double cluster compound [Nb6Cl14(MeCN)(4)] [Nb6Cl14(pyz)(4)].6MeCN (Me: methyl, pyz: pyrazine) with a layered structure resulting from weak intermolecular interactions},
  series = {Zeitschrift f{\"u}r Naturforschung},
  volume    = {78},
  journal   = {Zeitschrift f{\"u}r Naturforschung},
  number    = {5},
  publisher = {De Gruyter},
  address   = {Berlin},
  issn      = {0932-0776},
  doi       = {10.1515/znb-2023-0001},
  pages     = {279 -- 283},
  year      = {2023},
  abstract  = {The synthesis and the crystal structure of the double cluster compound [Nb6Cl14(MeCN)(4)][Nb6Cl14(pyz)(4)]middot6CH(3)CN are described. The synthesis is based on a partial ligand exchange reaction, which proceeds upon dissolving [Nb6Cl14(pyz)(4)]middot2CH(2)Cl(2) in acetonitrile. The compound is built up of two discrete neutral cluster units, which consist of octahedra of Nb-6 atoms coordinated by 12 edge-bridging chlorido and two terminal chlorido ligands, and four acetonitrile ligands on one and four pyrazine ligands on the other cluster unit. Co-crystallized acetonitrile molecules are also present. The single-crystal structure determination has revealed a cluster arrangement in which the [Nb6Cl14(pyz)(4)] units are connected by (halogen) lone-pair-(pyrazine) pi interactions. These lead to chains of [Nb6Cl14(pyz)(4)] clusters. These chains are further connected to cluster layers by (nitrile-halogen) dipole-dipole interactions, in which the [Nb6Cl14(MeCN)(4)] and co-crystallized MeCN molecules are also involved. These cluster layers are arranged parallel to the crystallographic {011} plane.},
  language  = {en}
}
@article{SperlichKoeckerling2021,
  author    = {Sperlich, Eric and K{\"o}ckerling, Martin},
  title     = {Cluster salts [Nb6Cl12(HIm)(6)]A(n) (with HIm=1H-imidazole and A=Mineral Acid Anion, n=1 or 2) made in and with Bronsted-basic ionic liquids and liquid mixtures},
  series = {ChemistryOpen},
  volume    = {10},
  journal   = {ChemistryOpen},
  number    = {2},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {2191-1363},
  doi       = {10.1002/open.202000266},
  pages     = {248 -- 254},
  year      = {2021},
  abstract  = {Four new hexanuclear niobium cluster compounds of the general formula [Nb6Cl12(HIm)(6)](A)(n) . x(solvent molecule) (HIm=1H-imidazole, A=mineral acid anion, Cl- (n=2) (1), (SO4)(2-) (n=1) (2), (CrO4)(2-) (n=1) (3), and (HAsO4)(2-) (n=1) (4)) were prepared. Their synthesis can be done in basic ionic liquids, which form on the addition of a mineral acid, which also delivers the counter anion for the final cluster compound, to an excess of the 1H-imidazole. Some addition of an auxiliary solvent, like methanol, improves the speed of crystallisation. The cluster unit comprises a hexanuclear Nb-6 unit of octahedral shape with the edges bridged by Cl atoms and the exo sites being occupied by N-bonded 1H-imidazole ligands. The cluster cation carries sixteen cluster-based electrons. Between the NH groups of the ligands of the cluster unit, the anions and the co-crystallised water (1), or 1H-imidazole and methanol molecules (2, 3, and 4) a network of hydrogen bonds exists.},
  language  = {en}
}
@article{SperlichKoeckerling2022,
  author    = {Sperlich, Eric and K{\"o}ckerling, Martin},
  title     = {[Nb6Cl14(pyrazine)(4)], a versatile precursor for ligand-supported hexanuclear niobium cluster compounds: synthesis, characterization, follow-up reactions, and intermolecular interactions},
  series = {Inorganic chemistry},
  volume    = {61},
  journal   = {Inorganic chemistry},
  number    = {5},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0020-1669},
  doi       = {10.1021/acs.inorgchem.1c03109},
  pages     = {2409 -- 2420},
  year      = {2022},
  abstract  = {The compound [Nb6Cl14(pyrazine)(4)]center dot 2CH(2)Cl(2) (1) was investigated for its suitability as a starting compound for new ligand-supported hexanuclear niobium cluster compounds. The synthesis, stability to air and increased temperature, solubility and usability for subsequent reactions of 1, and purification and separation of the reaction products are discussed. The compounds with cluster units [Nb6Cl14L4], where L = iso-quinoline N-oxides (2), 1,1-dimethylethylenediamines (3), or thiazoles (4), and [Nb6Cl14(PEt3)(3.76)(Et3PO)(0.24)]-[Nb6Cl14(MeCN)(4)]center dot 4MeCN (5) are presented as follow-up products. The crystal structures of compounds 1-5 are analyzed, and the structures are discussed with respect to their intraand intermolecular bonding situations and crystal packing. In addition to hydrogen bonds and pi-pi interactions, the appearance of chalcogen and halogen bonds and lone pair-pi interactions between Nb-6 cluster units was observed for the first time.},
  language  = {en}
}
@article{SperlichKoeckerling2021,
  author    = {Sperlich, Eric and K{\"o}ckerling, Martin},
  title     = {[Nb6Cl12(CH3OH)4(OCH3)2] ⋅ DABCO ⋅ 1.66 CH2Cl2},
  series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie : ZAAC = Journal of inorganic and general chemistry},
  volume    = {647},
  journal   = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie : ZAAC = Journal of inorganic and general chemistry},
  number    = {18},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0044-2313},
  doi       = {10.1002/zaac.202100138},
  pages     = {1759 -- 1763},
  year      = {2021},
  abstract  = {An easy-to-do synthesis for the hexanuclear niobium cluster compound [Nb6Cl12(CH3OH)(4)(OCH3)(2)] . DABCO . 1.66 CH2Cl2 has been developed. An one-pot reaction between the cluster precursor [Nb6Cl14(H2O)(4)] . 4H(2)O and methanol with the addition of DABCO leads to the crystallization of the title compound in high yield within a few minutes. The single-crystal X-ray structure of this cluster compound has been determined. Very strong, nearly symmetric intercluster hydrogen bonds Nb-6-MeO...H...OMe-Nb-6 are present between the cluster units. A bridging co-crystalline DABCO molecule is also involved in a three-dimensional hydrogen-bonding network.},
  language  = {en}
}