Copper(I) Thiocyanate Complex with 2-Benzylthio-4-(3,5-dimethyl-1H-pyrazol-1-yl)Pyrimidine: Synthesis, Polymorphism, and Luminescence

A copper(I) thiocyanate complex with 2-benzylthio-4-(3,5-dimethyl-1H-pyrazol-1-yl)pyrimidine (L) is prepared. According to the SC-XRD data, this complex is a ladder-like 1D coordination polymer [Cu2L2(SCN)2]n (P21/c space group). The ladder structure of the polymer is formed by bridging SCN– ions coordinated to Cu+ ions by N and S atoms, while the S atom is coordinated to two Cu+ ions. Thus, SCN– ions in this structure exhibit N,μ-S coordination. The L molecules are coordinated to Cu+ ions in monodentate mode via the N1 atom of the pyrimidine ring. The complex demonstrates green luminescence (λmax = 530 nm). Along with [Cu2L2(SCN)2]n, two other modifications of this complex - α-([CuL(SCN)] MeCN)n (P21/c space group) and β-([CuL(SCN)]·0.5MeCN)n (Aea2 space group) were characterized by SC-XRD, and it was shown that these complexes have a chained zigzag structure due to the N,S-coordination of SCN– ions, while L molecules are coordinated to the Cu+ ions in bidentate-cyclic mode via the N2 atom of the pyrimidine ring and the N4 atom of the pyrazole ring.