Hydrotris(1,2,4‐triazolyl)borato Complexes with the Main Group Elements Ca,Sr, and Pb – Unexpectedly Bent ML2 Structures and a Stereochemically Inactive Lone Pair at Lead(II) |
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| Authors: | Christoph Janiak Savas Temizdemir Tobias G Scharmann Antje Schmalstieg Jrg Demtschuk |
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| Abstract: | The coordination of the modified poly(azolyl)borato ligand hydrotris(1,2,4‐triazolyl)borato (L) with main group metals leads to complexes with coordination numbers of eight and the formula CaL2(H2O)2], SrL2(H2O)2], and PbL2(H2O)2]. The two L ligands coordinate in a “bent” arrangement to allow for the coordination of the two aqua ligands. This is in sharp contrast to six‐coordinated, pseudo‐octahedral CaTp2 and PbTp2 complexes Tp = hydrotris(pyrazolyl)borato]. The calcium, strontium, and lead complexes are isostructural. No stereochemical lone pair activity is evident in PbL2(H2O)2]. Two additional water molecules of crystallization complete the crystal structure of CaL2(H2O)2] · 2 H2O and PbL2(H2O)2] · 2 H2O. In the synthesis of PbL2(H2O)2] an intermediate of the form Pb(μ3‐L)(NO3)H2O] could isolated and structurally characterized. There, the lead(II) center is seven coordinated with a presumably stereochemically active lone pair. Long M–L bonds argue for a more ionic bonding to the modified tris(triazolyl)borato ligand when compared to analogous M–Tp complexes. |
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| Keywords: | Hydrotris(pyrazolyl)borato ligands Main‐group elements Lone pair Crystal structure |
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