π-Complexes of Cu(I) with Alkynes. Synthesis and Crystal Structure of Cs[CuCl2(HOCH2C≡CCH2OH)] ⋅ H2O

Abstract

This work continues systematic studies of the structure of π -complexes of Cu(I) halides with 2-butyne-1,4-diol formed in concentrated aqueous solutions of CuCl and MCl (where M are cations of the alkali metals, ammonium, and of organic amines).The crystals of molecular [CuCl ( HOCH 2 C ≡ CCH 2 OH ) and anionic ä[ CuBr 2 ( HOCH 2 C ≡ CCH 2 OH )] π -complexes were synthesized while studying the system ä Br -CuCl -H 2 O -HOCH 2 C ≡ CCH 2 OH [1] and were investigated by X-ray diffraction analysis. By replacing KBr by NH 4 Cl and then by RbCl in the above system, we obtained crystals of π -complex NH 4 [ CuCl 2 ( HOCH 2 C ≡ CCH 2 OH )] [2] and of two dimorphic complexes Rb [ CuCl 2 ( HOCH 2 C ≡ CCH 2 OH )] [3]. One dimorphic complex is also isostructural to the potassium [1] and ammonium [2] analogs.In order to establish the effect of an outer-sphere å + cation on the structure of anionic π -complexes of Cu(I) with 2-butyne-1,4-diol, we determined the structure of the crystals Cs [ CuCl 2 (EXPERIMENTAL Synthesis. Crystals I were synthesized by the direct reaction of Cu(I) chloride with 2-butyne-1,4-diol in a saturated aqueous solution of CsCl. A saturated aqueous solution of CsCl (0.01 mol, 1.7 g) was prepared at ~90° C and CuCl (0.01 mol, 1.0 g) was dissolved in it. Then, HOCH 2 C ≡ CCH 2 OH (0.01 mol, 0.9 g) was added and the solution was cooled to room temperature. The crystals of complex I formed as almost colorless triclinic prisms. The crystal density was measured by flotation method in a chloroform-bromoform mixture.X-ray diffraction analysis of single crystals I , which were preliminarily studied by photomethod, was performed on a single-crystal DARCh automated diffractometer ( åÓ K α radiation, θ /2 θ -scan mode). The crystallographic parameters and details of the data collection for complex I are given in Table 1.The structure was solved by the direct methods with CSD program package [4]. All non-hydrogen atoms were localized and refined by the least-squares method in isotropic approximation; the absorption correction was applied with DIFABS program. The hydrogen atoms were located geometrically. The final structure refinement was performed for non-hydrogen atoms in anisotropic (for the H atoms, in isotropic) approximation.The coordinates of atoms and their thermal parameters are listed in Table 2. RESULTS AND DISCUSSIONThe structure of complex I is shown in Fig. 1. Like the previously studied anionic π -complexes M [ CuCl 2 ( HOCH 2 C ≡ CCH 2 OH )] (M = , K + [2], Rb + [3]) and ä[ CuBr 2 ( HOCH 2 C ≡ CCH 2 OH )] [1], compound I consists of individual complex anions [ CuCl 2 ( HOCH 2 C ≡ CCH 2 OH )] -(Fig. 2) and hydrated Cs NH 4 + Abstract -Crystals of anionic π -complex Cs [ CuCl 2 ( HOCH 2 C≡CCH 2 OH)] · H 2 O were synthesized by reaction of 2-butyne-1,4-diol with CuCl in a saturated aqueous solution of CsCl at 90°C and studied by X-ray diffraction analysis. The crystals are triclinic (space group ; a = 10.155(4) Å, b = 7.828(4) Å, c = 7.115(3) Å, α = 102.62(4)°, β = 100.77(3)°, γ = 106.71(4)°, V = 509(1...