Identification of a novel tetragonally compressed six-coordinate copper(II) complex: preparation and characterization of a 3-chloroanilinium copper chloride complex, (3-chloroanilinium)8[CuCl6]Cl4

Abstract

A monomeric hexachlorocuprate(II) ion has been found in the compound (3-chloroanilinium) 8 [CuCl 6 ]Cl 4 , CuC 4 ,H 56 C1 8 N 8 . The compound crystallizes in the triclinic space group P1 with unit cell dimensions a = 8.5488(16) A, b = 13.964(6) A, c = 14.273(7) A, a = 90.46(4)*, B = 107.82(3)0, and y = 102.11(3)° with Z = 1. The coordination about the discrete [CuCl 6 4 , ion is that of a tetragonally compressed octahedron with bond distances Cu-Cl(1) = 2.2773(1i) A, Cu-Cl(2) = 2.6061(18) A, and Cu-Cl(3) = 2.6086(20) A. The two short bond distances are on the ordec frequently seen for copper-chloride bonds, but the remaining four bond distances are remarkably long for in-plane 4 + 2 coordination. The Cl(l)-2 Cu-Cl(la), Cl(2)-Cu-Cl(2a), and Cl(3)-Cu-Cl(3a) angles are strictly 180°, and the 12 remaining Cl(i)-Cu-Cl(j) angles differ from 90* by 0.4 to 1.0°. The EPR spectrum of a powdered sample is of the "reversed" nature indicative of a 2A ground state with g, = 2.06 and gl = 2.19. Magnetic susceptibility data provide evidence for antiferromagnetic interactions between the hexachlorocuprate cations, since there is a maximum in the magnetic susceptibility near 10 K. The data may be approximated by Heisenberg chain theory with J = -5.6 cm', g = 2.00, and an interchain exchange parameter J1 = -2.1 cm' Compounds with unusual formulations have been encountered in this research, 2 and studies described here on the title compound, (3-chloroanilinium) 8 [CuCl 6 ]Cl 4 , revealed the presence of the first discrete CuCl 6 4complex. Characterization of this new, unexpected complex by single-crystal X-ray diffraction studies and by magnetic methods are discussed in this Article. Experimental Section Synthesis. To 15.2 mL (0.15 mol) of 3-chloroaniline (Aldrich Chemical Co.) and 28.73 g (0.17 mol) of copper(II) chloride dihydrate were added approximately 150 mL of distilled water and 350 mL of concentrated hydrochloric acid. The resulting solution was heated, with stirring, to the boiling point. The solution was then allowed to cool, and copious quantities of yellow crystals deposited. The crystals were collected on a glass-frit funnel and were washed with anhydrous diethyl ether. Anal. Calcd. for

Jahn–Teller distortions in transition metal compounds, and their importance in functional molecular and inorganic materials

“…54 In the other, 80 unusual EPR behaviour in a fluxional Jahn-Teller crystal implied that a fraction of the sample adopts a {d z 2} 1 configuration as the temperature is raised. 56 That situation is analogous to Fig. 3, but where one of the minima in the Jahn-Teller potential surface corresponds to an axial compression.…”

“…A straightforward example is provided by the salt [3-ClC 6 H 4 NH 3 ] 8 CuCl 10 , 21 which contains centrosymmetric [CuCl 6 ] 4À octahedra with three unique Cu-Cl bonds (Fig. 2).…”

Metalloprotein active site structure determination: Synergy between X-ray absorption spectroscopy and X-ray crystallography

“…The former are very common in Cu(II) species, while the latter are either very rare or substantially absent [52]. One apparent exception to this was (3-chloroaniliunium) 8 (CuCl 6 ) Cl 4 , the crystal structure of which apparently showed tetragonally compressed distorted octahedral geometry [53] with four apparently equivalent Cu\Cl bonds at 2.609 Å and two at 2.277 Å (Fig. 6B b).…”

“…and because of this ΔE 0 was held fixed at a more reasonable value (−6.5 eV). (Table 2)) and with a simulation employing crystallographic bond-lengths [53] (b, red broken line). B shows the various distortions of [CuCl 6 ] 4− that have been discussed: a the axial elongated Jahn-Teller distortion; b axially compressed Jahn-Teller distortion; and c the dynamic equilibrium proposed by Ellis, Freeman and co-workers to explain the crystallographic results.…”

Crystal structure of [bis(2-aminoethyl-κN)(2-{[4-(trifluoromethyl)benzylidene]amino}ethyl)amine-κN]dichloridocopper(II)

“…Of the 318 structures, none incorporates the trifluoromethyl-substituted phenyl group presented here and none displays the dichloride counterions presented here. A survey of Cu-Cl bond-length elongations of similar structures in the literature produced examples such as 2.6061 18and 2.609 (2) Å (Tucker et al, 1991), 2.843 (1) to 3.140 (1) Å (Krysiak et al, 2014), 2.665 3and 2.731 (2) Å (Ferrari et al, 1998) and 2.7546 (9) Å (Odoko et al, 2002).…”