Two new organo-inorganic hybrids, (C2N2H10)[Cu(H2O)4](BeF4)2 (1) and (C2N2H10)[Cu(H2O)4](SeO4)2 (2), were prepared via the interaction of ethylenediamine, copper fluoroberyllate or selenate, and H2[BeF4]/H2SeO4 in aqueous solutions. The structures of 1 and 2 are similar to each other and the previously reported (C2N2H10)[Cu(H2O)4](SO4)2: monoclinic, P21/c, a = 5.1044(2) Å, b = 11.6171(4) Å, c = 10.1178(3) Å, and β = 94.431(3)° for 1; and a = 5.25020(10), b = 11.7500(2), c = 10.4434(2), and β = 94.5464(17)° for 2. All structures contain a square planar [Cu(H2O)4]2+ species, which coordinates, at rather long distances, two TX42- tetrahedral dianions in κ1 mode, forming relatively weak [Cu(H2O)4(TX4)2]2- complexes. These are linked together via hydrogen bonding into pseudo-chains; the ethylenediammonium cations link them into a 3D architecture. Compound 1 is, to the best of our knowledge, the first-though expected-representative of a hybrid organo-inorganic fluoroberyllate. The crystal chemical relations within the structural family (enH2)[Cu(H2O)4](TX4)2 are discussed.
Keywords: crystal chemistry; fluoroberyllate; organo-inorganic hybrid structures; selenate; solution synthesis; sulfate; topological features.