RESUMEN
A mononuclear square-planar CuII complex of (5-methyl-1H-pyrazol-3-yl)carbamate, [Cu(C5H6N3O2)2]·4H2O, was synthesized using a one-pot reaction from 5-methyl-3-pyrazolamine and copper(II) acetate in water under ambient conditions. The adsorption of carbon dioxide from air was facilitated by the addition of di-ethano-lamine to the reaction mixture. While di-ethano-lamine is not a component of the final product, it plays a pivotal role in the reaction by creating an alkaline environment, thereby enabling the adsorption of atmos-pheric carbon dioxide. The central copper(II) atom is in an (N2O2) square-planar coordination environment formed by two N atoms and two O atoms of two equivalent (5-methyl-1H-pyrazol-3-yl)carbamate ligands. Additionally, there are co-crystallized water mol-ecules within the crystal structure of this compound. These co-crystallized water mol-ecules are linked to the CuII mononuclear complex by O-Hâ¯O hydrogen bonds. According to Hirshfeld surface analysis, the most frequently observed weak inter-molecular inter-actions are Hâ¯O/Oâ¯H (33.6%), Hâ¯C/Câ¯H (11.3%) and Hâ¯N/Nâ¯H (9.0%) contacts.
RESUMEN
The reaction of cadmium bromide tetra-hydrate with 3-amino-pyrazole (3-apz) in ethano-lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena-poly[[di-bromido-cadmium(II)]-bis-(µ-3-amino-1H-pyrazole)-κ2 N 3:N 2;κ2 N 2:N 3], [CdBr2(C3H5N3)2]n or [CdBr2(3-apz)2]n. Its asymmetric unit consists of a half of a Cd2+ cation, a bromide anion and a 3-apz mol-ecule. The Cd2+ cations are coordinated by two bromide anions and two 3-apz ligands, generating trans-CdN4Br2 octa-hedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand mol-ecules and bromide anions of neighboring chains are linked through inter-chain hydrogen bonds into a two-dimensional network. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative qu-anti-tative contributions of the weak inter-molecular contacts.
RESUMEN
Hofmann-like cyanometallic complexes represent one of the biggest and well-known classes of FeII spin-crossover compounds. In this paper, we report on the first FeII Hofmann clathrate analogues with unsubstituted 1,2,3-triazole, which exhibit temperature induced spin transition. Two new coordination polymers with the general formula [FeII(1,2,3-triazole)2MII(CN)4] (M = Pt, Pd) undergo abrupt hysteretic spin crossover in the range of 190-225 K as revealed by magnetic susceptibility measurements. Two compounds are isostructural and are built of infinite cyanometallic layers which are supported by 1,2,3-triazole ligands. The thermal hysteresis loop is very stable at different scan rates from 0.5 to 10 K min-1. The compounds display strong thermochromic effect, changing their colour from pink in the low-spin state to white in the high-spin state. Our findings show that 1,2,3-triazole is suitable for elaboration of spin-crossover Hofmann clathrate analogues, and its use instead of more classical azines can advantageously expand this family of complexes.
RESUMEN
In the title polymeric complex, {[FePt(CN)4(H2O)2]·2C3H6O} n , the FeII cation has an octa-hedral [FeN4O2] geometry being coordinated by two water mol-ecules and four cyanide anions. The Pt cation is located on an inversion centre and has a square-planar coordination environment formed by four cyanide groups. The tetra-cyano-platinate anions bridge the FeII cations to form infinite two-dimensional layers that propagate in the bc plane. Two guest mol-ecules of acetone per FeII are located between the layers. These guest acetone mol-ecules inter-act with the coordinated water mol-ecules by O-Hâ¯O hydrogen bonds.
