In general, if the atoms that make up the ring contain heteroatoms, such rings become heterocycles, and organic compounds containing heterocycles are called heterocyclic compounds. An article called Electronic structures of highly symmetrical compounds of f elements.Part 35. Crystal and molecular structure of tris(hydrotris(1-pyrazolyl)borato)lanthanide(III) (LnTp3; Ln = La, Eu), and electronic structure of EuTp3, published in 2002-09-30, which mentions a compound: 18583-60-3, Name is Potassiumtris(1-pyrazolyl)borohydride, Molecular C9H10BKN6, COA of Formula: C9H10BKN6.
LnTp3 (Ln = La, Eu; Tp3 = hydrotris(1-pyrazolyl)borate) were prepared from KTp and LnCl3. In contrast to the result of a previous luminescence measurement but in accordance with previous IR and FIR spectroscopic investigations the Eu3+ central ion of tris(hydrotris(1-pyrazolyl)borato)europium(III) (EuTp3) is coordinated according to a single crystal x-ray anal. in 1st coordination sphere by 9 N atoms in the shape of a tricapped trigonal prism, resulting in an effective crystal field (CF) of symmetry D3h. Crystal data of Eu complex: hexagonal, P63/m, a = 11.709(3), c = 13.672(2), V = 1623.3(1.4), Z = 2, ρc = 1.618 g/cm3, μ(MoKα) = 19.83 cm-1, F(000) = 792, 487 observed reflections with I > 3σ(I), R = 0.0271, Rw = 0.0324; La complex: hexagonal, P63/m, a = 11.814(3), c = 13.698(5), V = 1655.8(1.5), Z = 2, ρc = 1.560 g/cm3, μ(MoKα) = 13.43 cm-1, F(000) = 780, 603 observed reflections with I > 3σ(I), R = 0.0366, Rw = 0.0568. However, if one considers the whole mol., mol. C3h symmetry is present in the crystal. This also holds for the corresponding La compound The absorption spectrum of powd. EuTp3 was recorded at ≈5 K, and the luminescence spectrum at 77 K. On the basis of these optical spectra, an exptl. CF splitting pattern was derived, which comprises a sequence of energy levels of Γ4 and Γ6 symmetry, resp. Sign and absolute value of the CF parameter B20 were derived on an exptl. basis, and model calculations adopting the approximations of electrostatic point charge and angular overlap models, resp., predict neg. values for the CF parameters B40 and B60. Keeping these signs, the exptl. derived truncated CF splitting pattern of EuTp3 could be reproduced by fitting the free parameters of a phenomenol. Hamiltonian.
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Reference:
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