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Crystal structure of the thermochromic bis­­(di­ethyl­ammonium) tetra­chlorido­cuprate(II) complex

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aDepartment of Chemistry & Physics, Saint Mary's College, Notre Dame, IN 46556, USA, bDepartment of Chemistry, Yale University, New Haven, CT, 06520, USA, and cDepartment of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
*Correspondence e-mail: koshin@saintmarys.edu

Edited by S. Parkin, University of Kentucky, USA (Received 5 October 2015; accepted 4 December 2015; online 1 January 2016)

In the structure of the title complex salt, (Et2NH2)2[CuCl4], the asymmetric unit consists of four unique di­ethyl­ammonium cations and three unique tetra­chlorido­cuprate anions. Two of the three anions are located with their copper atoms on independent crystallographic twofold axes, while the remaining tetra­chlorido­cuprate is located at a general position of the ortho­rhom­bic space group P21212. Two of the three Cu atoms adopt a distorted square-planar/disphenoidal geometry and the third Cu atom has a regular square-planar coordination environment. The di­ethyl­ammonium cations form an extensive hydrogen-bonded network through N—H⋯Cl inter­actions with the tetra­chlorido­cuprate anions, resulting in a two-dimensional sheet-like hydrogen-bonded network parallel to the ab direction. The complex was observed to undergo a color shift from deep green at room temperature to pale yellow at temperatures above 328 K.

1. Chemical context

Thermochromic compounds exhibit a reversible change in color corresponding to a change in temperature. This change can occur in the solid state or in solution and is typically due to geometry rearrangement at the mol­ecular level. Several mechanisms have been proposed for this rearrangement, including phase transitions, changes in solvation, changes in ligand geometry, coordination number, and finally crystal packing (White & LeBlanc, 1999[White, M. A. & LeBlanc, M. (1999). J. Chem. Educ. 76, 1201-1205.]). There are two generally accepted classes of thermochromism: (i) continuous; used to describe a gradual change in color, most likely due to breaking or rearrangement of the crystal structure (Roberts et al., 1981[Roberts, S. A., Bloomquist, D. R., Willett, R. D. & Dodgen, H. W. (1981). J. Am. Chem. Soc. 103, 2603-2610.]), and (ii) discontinuous; used to describe a dramatic change in color over a specific or small temperature range (Van Oort, 1988[Van Oort, M. J. (1988). J. Chem. Educ. 65, 84-84.]). Two classes of thermochromic compounds that have practical applications today include liquid crystals and leuco dyes. Liquid crystals exist on the boundary between the liquid and solid states. They are classified as discontinuous due to the chemistry of their transitions (Amberger & Savji, 2008[Amberger, B. & Savji, N. (2008). https://www3.amherst.edu/thoughts/contents/amberger-thermochromism. html]). As a result, thermochromic liquid crystals have been used to make `mood rings', thermometers, and game pieces (Chandler, 2012[Chandler, N. (2012). https://electronics.howstuffworks.com/gadgets/other-gadgets/ thermochromic-ink5.html.]). Although color changes in liquid crystals are more sensitive to external stimuli such as temperature changes, they have a highly specialized manufacturing process and are difficult to make. For this reason, new thermochromic compounds such as leuco dyes are highly sought after. Leuco dyes are easier to work with and less sensitive to temperature changes. They have been used in advertising labels, textiles, and packaging for microwaveable syrup bottles and beverage cans that indicate content temperature changes (Muthyala, 1997[Muthyala, R. (1997). In Chemistry and Applications of Leuco Dyes. New York: Plenum Press.]). Given the intriguing applications of thermochromic compounds, we report the synthesis and structural characterization of a bis­(di­ethyl­ammonium) tetra­chlorido­cuprate complex (I)[link] that displays thermochromic properties.

[Scheme 1]

2. Structural commentary

The asymmetric unit of the thermochromic complex (Et2NH2)2[CuCl4] consists of four unique di­ethyl­ammonium cations and one full and two half tetra­chlorido­cuprate anions (Fig. 1[link]). The di­ethyl­ammonium cations and the complete anion (Cu1) occupy general positions within the unit cell. The two half-tetra­chlorido­cuprate anions are located on crystallographic twofold axes at [½, ½, z] and [½, 0, z]. Each copper cation exhibits different coordination geometries. Cu2, located on a twofold rotation axis, has close to ideal square-planar geometry, with trans Cl—Cu—Cl angles close to 180° (Table 1[link]). Analysis of these angles through the τ4 metric developed by Yang et al. (2007[Yang, L., Powell, D. R. & Houser, R. P. (2007). Dalton Trans. pp. 955-964.]) yields a τ4 value of 0.02 for Cu2. A value of zero (0) is indicative of an ideal square-planar geometry while a value of one (1) indicates an ideal tetra­hedral geometry. In contrast, Cu1 and Cu3 adopt distorted square-planar geometries, tending to a disphenoidal (or `see-saw') type geometry with τ4 = 0.27 and 0.48, respectively. The τ4 value is calculated from: [360 − (α + β)]/141; where α and β are the two largest angles about the four-coordinate copper(II) atom in question. However, these distortions are solely in the bond angles about the copper(II) atoms: all of the Cu—Cl bond lengths are similar (Table 1[link]). A mean-plane analysis of each copper(II) atom shows the gradual change from the atoms being nearly co-planar (Cu2), through an inter­mediate distortion (Cu1) to a more pronounced out-of-plane arrangement of chlorine atoms around Cu3, in which the chlorine atoms are located 0.68 Å from the mean plane (Table 2[link]). These distortions, along with the hydrogen-bonded network described below, are likely the cause for the thermochromism observed within the sample.

Table 1
Selected geometric parameters (Å, °)

Cu1—Cl2 2.2474 (7) Cu2—Cl6i 2.2689 (6)
Cu1—Cl1 2.2598 (7) Cu2—Cl6 2.2689 (6)
Cu1—Cl3 2.2620 (7) Cu3—Cl8 2.2475 (7)
Cu1—Cl4 2.2702 (7) Cu3—Cl8ii 2.2475 (7)
Cu2—Cl5 2.2644 (6) Cu3—Cl7 2.2481 (6)
Cu2—Cl5i 2.2644 (6) Cu3—Cl7ii 2.2481 (6)
       
Cl2—Cu1—Cl1 93.20 (3) Cl5—Cu2—Cl6 90.34 (2)
Cl2—Cu1—Cl3 92.13 (3) Cl5i—Cu2—Cl6 89.66 (2)
Cl1—Cu1—Cl3 161.22 (3) Cl6i—Cu2—Cl6 179.81 (4)
Cl2—Cu1—Cl4 160.16 (3) Cl8—Cu3—Cl8ii 146.10 (4)
Cl1—Cu1—Cl4 90.46 (3) Cl8—Cu3—Cl7 94.66 (2)
Cl3—Cu1—Cl4 90.60 (3) Cl8ii—Cu3—Cl7 95.17 (2)
Cl5—Cu2—Cl5i 176.78 (4) Cl8—Cu3—Cl7ii 95.17 (2)
Cl5—Cu2—Cl6i 89.66 (2) Cl8ii—Cu3—Cl7ii 94.66 (2)
Cl5i—Cu2—Cl6i 90.34 (2) Cl7—Cu3—Cl7ii 145.83 (4)
Symmetry codes: (i) -x+1, -y+1, z; (ii) -x+1, -y, z.

Table 2
Mean plane deviations for [CuCl4]2− anions (Å)

*Because these pairs of atoms are symmetry related by a twofold axis, deviations are identical.

Atom Deviation Atom Deviation Atom Deviation
Cu1 0.0091 (4) Cu2 0.0239 (5) Cu3 −0.0021 (5)
Cl1 0.3740 (4) Cl5/Cl5i* −0.0397 (6) Cl7/Cl7ii* 0.6583 (5)
Cl2 −0.3745 (4) Cl6/Cl6i* 0.0277 (6) Cl8/Cl8ii* −0.6573 (6)
Cl3 0.3769 (4)        
Cl4 −0.3854 (4)        
           
r.m.s. deviation 0.3379   0.0324   0.5883
Symmetry codes: (i) −x + 1, −y + 1, z; (ii) −x + 1, −y, z.
[Figure 1]
Figure 1
Atom labelling scheme for bis­(di­ethyl­ammonium) tetra­chlorido­cuprate. Atomic displacement ellipsoids are depicted at the 50% probability level and H atoms as spheres of an arbitrary radius. [Symmetry codes: (i) −x + 1, −y + 1, z; (ii) −x + 1, −y, z.]

3. Supra­molecular features

The extended structure consists of the di­ethyl­ammonium cations forming an extended hydrogen-bonded network with the chlorine atoms of the tetra­chlorido­cuprate anions. All of the ammonium cations serve as hydrogen-bond donors; the ammonium cation hydrogen atoms were located in difference Fourier maps and refined freely. Ammonium cations involving N1, N2 and N3 all serve as donors of a single hydrogen-bond to one chlorine and as a donor of a bifurcated hydrogen bond to a pair of chlorine atoms on one copper(II) atom. The hydrogen atoms on N4 both form bifurcated inter­actions, albeit weakly (Table 3[link]). All of the chlorine atoms serve as hydrogen-bond acceptors (Table 3[link], Fig. 2[link]). While some of the reported inter­actions are quite long (N⋯Cl > 3.2 Å), and could be classified as weak inter­actions (Jeffrey, 1997[Jeffrey, G. (1997). In An Introduction to Hydrogen Bonding. Oxford University Press. Oxford, England.]), they are observed where the hydrogen atom is inter­acting with two chlorine atoms that are adjacent to each other/bonded to the same copper (II) atom and are considered by us to be bifurcated hydrogen bonds.

Table 3
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1A⋯Cl5iii 0.84 (3) 2.74 (3) 3.316 (2) 128 (2)
N1—H1A⋯Cl6iv 0.84 (3) 2.53 (3) 3.323 (2) 158 (2)
N1—H1B⋯Cl1 0.96 (3) 2.23 (3) 3.192 (2) 178 (3)
N2—H2C⋯Cl2v 0.84 (3) 2.53 (3) 3.316 (2) 155 (3)
N2—H2C⋯Cl3v 0.84 (3) 2.72 (3) 3.319 (3) 129 (2)
N2—H2D⋯Cl4 0.91 (3) 2.28 (3) 3.180 (2) 171 (3)
N3—H3C⋯Cl7 0.82 (3) 2.39 (3) 3.209 (3) 176 (3)
N3—H3D⋯Cl3 0.92 (3) 2.53 (3) 3.383 (2) 154 (3)
N3—H3D⋯Cl4 0.92 (3) 2.56 (3) 3.198 (3) 127 (2)
N4—H4D⋯Cl7vi 0.82 (3) 2.93 (3) 3.374 (3) 116 (2)
N4—H4D⋯Cl8vii 0.82 (3) 2.40 (3) 3.202 (3) 167 (2)
N4—H4E⋯Cl5 0.86 (3) 2.47 (3) 3.283 (2) 159 (3)
N4—H4E⋯Cl6 0.86 (3) 2.75 (3) 3.311 (3) 125 (2)
Symmetry codes: (iii) -x+1, -y+1, z+1; (iv) x, y, z+1; (v) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]; (vi) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, -z]; (vii) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z].
[Figure 2]
Figure 2
Hydrogen-bonding scheme for bis­(di­ethyl­ammonium) tetra­chlorido­cuprate viewed (a) along the c axis and (b) along the a axis. Atomic displacement ellipsoids are depicted at the 50% probability level and H atoms as spheres of an arbitrary radius. Ethyl H atoms have been omitted for clarity. Hydrogen bonds are shown as blue dashed lines.

The Cu2 anion is notable because all four chlorine atoms are acceptors of bifurcated hydrogen bonds from N1 and N4; Cu2 is located on a twofold rotation axis. N1 also donates a single hydrogen bond to Cl1. N2 has a bifurcated hydrogen bond to chlorine atoms Cl2 and Cl3 on Cu1 and also forms a single donor hydrogen bond to Cl4 of an adjacent Cu1 anion. The di­ethyl­ammonium cation that includes N3 has both a bifurcated hydrogen bond to Cl3 and Cl4 (Cu1) and a single donor hydrogen bond to Cl7 (Cu3). The hydrogen atoms on N4 are donor atoms of bifurcated hydrogen bonds to Cl5/Cl6 on Cu2 and Cl7/Cl8 on Cu3. The ultimate result of this prolific hydrogen-bond bridging of [CuCl4]2− anions is a two-dimensional sheet extending parallel to the ab plane (Fig. 2[link]). Inspection of this plane along the crystallographic a axis reveals a gentle corrugation of the sheet (Fig. 2[link]b). This hydrogen-bonded sheet is likely the driving force for crystallization (Desiraju, 2002[Desiraju, G. R. (2002). Acc. Chem. Res. 35, 565-573.]).

4. Database survey

There are 59 structures that incorporate the bis-di­ethyl­ammonium ligand moiety with a tetra­chlorido­cuprate complex (Groom & Allen 2014[Groom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662-671.]; CSD Version 5.36). Of those 59 structures, 23 incorporate bridging chloride ligands, while 36 have independent tetra­chlorido­cuprate complexes present. Thirteen structures incorporate the bis-ethyl­ammonium ligand as a linear structure as presented in this manuscript. In addition, of the 59 structures, eleven show the tetra­chlorido­cuprate complex adopting a distorted square-planar geometry as presented in complex (I)[link].

5. Synthesis and crystallization

The synthetic procedure is outlined in Fig. 3[link].

[Figure 3]
Figure 3
The synthetic scheme.

General Procedure: Bis-di­ethyl­ammonium tetra­chlorido­cuprate was synthesized according to literature procedures (Choi & Larrabee, 1989[Choi, S. & Larrabee, J. A. (1989). J. Chem. Educ. 66, 774-776.]). Reagents and solvents used were purchased from commercial sources (Sigma-Aldrich and Fisher Scientific). A Perkin Elmer FT–ATR spectrometer was used to collect IR spectra with three scans from 200 nm to 800 nm at a resolution of 1 cm−1. The melting point was recorded on a Fluka Mel-Temp melting point apparatus (Electrothermal) equipped with 51 II thermometer.

Synthesis of bis-di­ethyl­ammonium tetra­chlorido­cuprate: Di­ethyl­ammonium hydro­chloride (2.22 g, 20.3 mmol) was dissolved in 15 mL of 2-propanol to afford a clear solution. Copper(II) chloride dihydrate (1.75 g, 10.1 mmol) was dissolved in 3 ml ethanol producing a dark green solution. Both solutions were mixed, generating a brownish-black colored product that was heated in a water bath for 3 min. Upon removal from the water bath, a 10 ml solution of 20% v/v 2-propanol and ethyl acetate was added to the mixture. The mixture was placed in an ice bath, which gave a bright-green precipitate. The precipitate was filtered, washed with three 10 ml aliquots of ethyl acetate, then air dried to produce the desired product as a bright green thermochromic solid (1.72 g, 48%). M.p. 359.2–359.5 K.

Thermochromic properties: Green-colored solid at temperatures lower than 327 K and bright-yellow colored solid at temperatures greater than 328 K.

FT–ATR (solid): v (cm−1) = 3060 (s), 3009 (s), 2986 (br), 2956 (s), 2852 (s), 2826 (s). Green crystals for complex (I)[link] were obtained by slow diffusion of diethyl ether into a solution of bis-di­ethyl­ammonium tetra­chlorido­cuprate made in methanol.

6. Refinement

Details of the refinement are found in Table 4[link]. All non-hydrogen atoms were refined with anisotropic atomic displacement parameters. Hydrogen atoms bonded to carbon were included in geometrically calculated positions with Uiso(H) = 1.2Ueq(Cmethyl­ene) and 1.5Ueq(Cmeth­yl). Methyl groups were allowed a torsional degree of freedom and C—H distances were set to 0.99 Å (methyl­ene) and 0.98 Å (meth­yl). Ammonium hydrogen atoms were located in difference Fourier maps and refined freely. The structure was refined as an inversion twin, with a 0.52:0.48 twin ratio. Because this ratio is close to 0.5, data were inspected carefully for signs of missed inversion symmetry; no higher symmetry was found. One reflection (0 0 1) was obscured by the beamstop and was omitted from the refinement.

Table 4
Experimental details

Crystal data
Chemical formula (C4H12N)[Cl4Cu]
Mr 353.63
Crystal system, space group Orthorhombic, P21212
Temperature (K) 120
a, b, c (Å) 14.8766 (13), 29.903 (3), 7.3102 (6)
V3) 3252.0 (5)
Z 8
Radiation type Mo Kα
μ (mm−1) 1.98
Crystal size (mm) 0.20 × 0.13 × 0.09
 
Data collection
Diffractometer Bruker APEXII
Absorption correction Multi-scan (SADABS; Bruker, 2014[Bruker (2014). APEX2, SAINT and SADABS. Bruker-Nonius AXS Inc. Madison, Wisconsin, USA.])
Tmin, Tmax 0.868, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 67459, 6699, 6278
Rint 0.040
(sin θ/λ)max−1) 0.627
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.020, 0.043, 1.10
No. of reflections 6699
No. of parameters 313
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.34, −0.22
Absolute structure Refined as an inversion twin
Absolute structure parameter 0.523 (10)
Computer programs: APEX2 and SAINT (Bruker, 2014[Bruker (2014). APEX2, SAINT and SADABS. Bruker-Nonius AXS Inc. Madison, Wisconsin, USA.]), SHELXS (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Computing details top

Data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: publCIF (Westrip, 2010).

Bis(diethylammonium) tetrachloridocuprate top
Crystal data top
(C4H12N)[Cl4Cu]Dx = 1.445 Mg m3
Mr = 353.63Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P21212Cell parameters from 9060 reflections
a = 14.8766 (13) Åθ = 2.5–26.4°
b = 29.903 (3) ŵ = 1.98 mm1
c = 7.3102 (6) ÅT = 120 K
V = 3252.0 (5) Å3Block, green
Z = 80.20 × 0.13 × 0.09 mm
F(000) = 1464
Data collection top
Bruker APEXII
diffractometer
6699 independent reflections
Radiation source: fine-focus sealed tube6278 reflections with I > 2σ(I)
Detector resolution: 8.33 pixels mm-1Rint = 0.040
combination of ω and φ–scansθmax = 26.5°, θmin = 1.4°
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
h = 1818
Tmin = 0.868, Tmax = 1.000k = 3737
67459 measured reflectionsl = 99
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.020H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.043 w = 1/[σ2(Fo2) + (0.0186P)2 + 0.6108P]
where P = (Fo2 + 2Fc2)/3
S = 1.10(Δ/σ)max = 0.001
6699 reflectionsΔρmax = 0.34 e Å3
313 parametersΔρmin = 0.22 e Å3
0 restraintsAbsolute structure: Refined as an inversion twin
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.523 (10)
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refined as a 2-component inversion twin.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cu10.50594 (2)0.24256 (2)0.71725 (4)0.01615 (8)
Cl10.44388 (5)0.30272 (2)0.85530 (10)0.02928 (17)
Cl20.63668 (5)0.27793 (2)0.66434 (11)0.02476 (15)
Cl30.56951 (4)0.17463 (2)0.67495 (10)0.02242 (14)
Cl40.36734 (4)0.21319 (2)0.66777 (11)0.02605 (16)
Cu20.50000.50000.17777 (5)0.01407 (9)
Cl50.36104 (4)0.53083 (2)0.16907 (11)0.02239 (14)
Cl60.43871 (4)0.43052 (2)0.17828 (10)0.02188 (14)
Cu30.50000.00000.23370 (6)0.01802 (10)
Cl70.57118 (4)0.06253 (2)0.32404 (10)0.02721 (16)
Cl80.37459 (5)0.03573 (2)0.14408 (10)0.02458 (15)
N10.59486 (16)0.37538 (8)0.9442 (3)0.0175 (5)
H1A0.5680 (18)0.3946 (8)1.007 (4)0.010 (7)*
H1B0.549 (2)0.3539 (11)0.914 (4)0.040 (10)*
C10.6240 (2)0.33898 (9)1.2396 (4)0.0286 (7)
H1C0.57240.31961.21460.043*
H1D0.60420.36511.30980.043*
H1E0.66900.32241.31020.043*
C20.66469 (18)0.35417 (9)1.0618 (4)0.0211 (6)
H2A0.71340.37591.08650.025*
H2B0.69110.32820.99720.025*
C30.62953 (18)0.39622 (8)0.7727 (4)0.0194 (6)
H3A0.66120.37340.69890.023*
H3B0.67310.42010.80380.023*
C40.55385 (19)0.41575 (9)0.6626 (4)0.0274 (6)
H4A0.57790.42920.55060.041*
H4B0.52310.43870.73490.041*
H4C0.51110.39210.63060.041*
N20.24950 (17)0.29865 (7)0.5700 (3)0.0179 (5)
H2C0.209 (2)0.2864 (10)0.506 (4)0.026 (9)*
H2D0.288 (2)0.2763 (11)0.604 (5)0.040 (10)*
C50.3393 (2)0.31134 (10)0.2914 (4)0.0360 (8)
H5A0.29110.29860.21640.054*
H5B0.38110.28760.32750.054*
H5C0.37160.33410.22060.054*
C60.29959 (19)0.33250 (9)0.4599 (4)0.0232 (6)
H6A0.34820.34560.53520.028*
H6B0.25830.35690.42360.028*
C70.20750 (19)0.31699 (8)0.7396 (4)0.0215 (6)
H7A0.16040.33890.70600.026*
H7B0.25370.33280.81270.026*
C80.1665 (2)0.28018 (9)0.8528 (4)0.0287 (7)
H8A0.12000.26490.78140.043*
H8B0.13960.29300.96340.043*
H8C0.21330.25870.88740.043*
N30.40456 (16)0.12593 (8)0.4264 (3)0.0175 (5)
H3C0.446 (2)0.1091 (9)0.396 (4)0.022 (8)*
H3D0.434 (2)0.1453 (10)0.504 (5)0.035 (9)*
C90.4391 (2)0.17652 (10)0.1694 (5)0.0391 (8)
H9A0.41260.19330.06770.059*
H9B0.48390.15550.12180.059*
H9C0.46810.19730.25450.059*
C100.36649 (19)0.15100 (9)0.2681 (4)0.0240 (6)
H10A0.32000.17210.31200.029*
H10B0.33750.12980.18240.029*
C110.33663 (19)0.10125 (9)0.5365 (4)0.0232 (6)
H11A0.30530.07940.45740.028*
H11B0.29140.12250.58400.028*
C120.3800 (2)0.07722 (11)0.6935 (4)0.0391 (8)
H12A0.42340.05540.64640.059*
H12B0.33390.06170.76500.059*
H12C0.41120.09890.77170.059*
N40.25278 (17)0.45225 (7)0.0543 (3)0.0170 (5)
H4D0.2139 (19)0.4704 (9)0.082 (4)0.014 (8)*
H4E0.289 (2)0.4666 (10)0.016 (4)0.029 (9)*
C130.1651 (2)0.43942 (10)0.2256 (4)0.0336 (8)
H13A0.13880.41630.30390.050*
H13B0.11780.45980.18410.050*
H13C0.21030.45620.29500.050*
C140.20883 (19)0.41794 (9)0.0629 (4)0.0215 (6)
H14A0.25430.39600.10480.026*
H14B0.16300.40170.00930.026*
C150.29877 (19)0.43473 (9)0.2199 (4)0.0206 (6)
H15A0.25580.41690.29310.025*
H15B0.34870.41480.18270.025*
C160.3352 (2)0.47240 (9)0.3351 (4)0.0288 (7)
H16A0.37870.48970.26350.043*
H16B0.28570.49190.37310.043*
H16C0.36480.46010.44370.043*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.01612 (17)0.01610 (13)0.01623 (14)0.00025 (13)0.00063 (14)0.00147 (11)
Cl10.0210 (3)0.0272 (3)0.0396 (4)0.0021 (3)0.0045 (3)0.0171 (3)
Cl20.0235 (4)0.0192 (3)0.0315 (4)0.0043 (3)0.0095 (3)0.0028 (3)
Cl30.0173 (3)0.0171 (3)0.0329 (4)0.0018 (2)0.0008 (3)0.0020 (3)
Cl40.0167 (3)0.0195 (3)0.0420 (4)0.0020 (3)0.0057 (3)0.0080 (3)
Cu20.0138 (2)0.01348 (18)0.01494 (19)0.00051 (18)0.0000.000
Cl50.0150 (3)0.0156 (3)0.0366 (4)0.0012 (2)0.0013 (3)0.0009 (3)
Cl60.0176 (3)0.0145 (3)0.0336 (4)0.0004 (2)0.0002 (3)0.0003 (3)
Cu30.0163 (2)0.0211 (2)0.0167 (2)0.0010 (2)0.0000.000
Cl70.0163 (3)0.0299 (3)0.0353 (4)0.0014 (3)0.0005 (3)0.0148 (3)
Cl80.0244 (4)0.0192 (3)0.0301 (4)0.0011 (3)0.0110 (3)0.0005 (3)
N10.0179 (12)0.0165 (11)0.0180 (12)0.0017 (10)0.0007 (10)0.0014 (10)
C10.0357 (18)0.0244 (14)0.0257 (16)0.0045 (13)0.0027 (14)0.0024 (12)
C20.0201 (15)0.0195 (13)0.0237 (15)0.0045 (11)0.0048 (12)0.0033 (11)
C30.0209 (14)0.0177 (12)0.0197 (14)0.0010 (11)0.0029 (12)0.0016 (11)
C40.0304 (16)0.0282 (14)0.0237 (14)0.0006 (13)0.0008 (14)0.0042 (12)
N20.0162 (12)0.0170 (11)0.0206 (12)0.0007 (10)0.0002 (10)0.0025 (10)
C50.042 (2)0.0366 (16)0.0295 (18)0.0040 (15)0.0156 (15)0.0008 (14)
C60.0229 (15)0.0222 (14)0.0244 (15)0.0025 (12)0.0024 (12)0.0023 (12)
C70.0227 (15)0.0207 (13)0.0209 (14)0.0027 (11)0.0015 (12)0.0053 (11)
C80.0299 (16)0.0290 (14)0.0271 (16)0.0044 (13)0.0086 (14)0.0009 (13)
N30.0147 (12)0.0180 (12)0.0198 (12)0.0004 (10)0.0008 (10)0.0011 (10)
C90.0379 (19)0.0448 (17)0.0347 (18)0.0064 (15)0.0010 (17)0.0159 (16)
C100.0227 (15)0.0254 (13)0.0237 (15)0.0007 (12)0.0074 (13)0.0031 (12)
C110.0201 (15)0.0245 (14)0.0251 (15)0.0035 (12)0.0050 (12)0.0008 (12)
C120.0382 (19)0.0482 (19)0.0310 (18)0.0069 (15)0.0045 (15)0.0184 (16)
N40.0147 (13)0.0158 (11)0.0204 (12)0.0008 (10)0.0018 (10)0.0014 (10)
C130.043 (2)0.0294 (15)0.0285 (17)0.0068 (14)0.0100 (15)0.0024 (13)
C140.0207 (15)0.0183 (13)0.0255 (15)0.0030 (11)0.0001 (12)0.0043 (11)
C150.0183 (14)0.0217 (12)0.0217 (14)0.0024 (11)0.0020 (12)0.0046 (11)
C160.0289 (16)0.0312 (15)0.0264 (15)0.0032 (13)0.0082 (14)0.0031 (14)
Geometric parameters (Å, º) top
Cu1—Cl22.2474 (7)C7—C81.506 (4)
Cu1—Cl12.2598 (7)C7—H7A0.9900
Cu1—Cl32.2620 (7)C7—H7B0.9900
Cu1—Cl42.2702 (7)C8—H8A0.9800
Cu2—Cl52.2644 (6)C8—H8B0.9800
Cu2—Cl5i2.2644 (6)C8—H8C0.9800
Cu2—Cl6i2.2689 (6)N3—C111.488 (3)
Cu2—Cl62.2689 (6)N3—C101.491 (3)
Cu3—Cl82.2475 (7)N3—H3C0.82 (3)
Cu3—Cl8ii2.2475 (7)N3—H3D0.92 (3)
Cu3—Cl72.2481 (6)C9—C101.507 (4)
Cu3—Cl7ii2.2481 (6)C9—H9A0.9800
N1—C21.490 (3)C9—H9B0.9800
N1—C31.492 (3)C9—H9C0.9800
N1—H1A0.84 (3)C10—H10A0.9900
N1—H1B0.96 (3)C10—H10B0.9900
C1—C21.504 (4)C11—C121.500 (4)
C1—H1C0.9800C11—H11A0.9900
C1—H1D0.9800C11—H11B0.9900
C1—H1E0.9800C12—H12A0.9800
C2—H2A0.9900C12—H12B0.9800
C2—H2B0.9900C12—H12C0.9800
C3—C41.502 (4)N4—C151.486 (3)
C3—H3A0.9900N4—C141.488 (3)
C3—H3B0.9900N4—H4D0.82 (3)
C4—H4A0.9800N4—H4E0.86 (3)
C4—H4B0.9800C13—C141.500 (4)
C4—H4C0.9800C13—H13A0.9800
N2—C61.492 (3)C13—H13B0.9800
N2—C71.493 (3)C13—H13C0.9800
N2—H2C0.84 (3)C14—H14A0.9900
N2—H2D0.91 (3)C14—H14B0.9900
C5—C61.506 (4)C15—C161.507 (4)
C5—H5A0.9800C15—H15A0.9900
C5—H5B0.9800C15—H15B0.9900
C5—H5C0.9800C16—H16A0.9800
C6—H6A0.9900C16—H16B0.9800
C6—H6B0.9900C16—H16C0.9800
Cl2—Cu1—Cl193.20 (3)N2—C7—H7B109.5
Cl2—Cu1—Cl392.13 (3)C8—C7—H7B109.5
Cl1—Cu1—Cl3161.22 (3)H7A—C7—H7B108.0
Cl2—Cu1—Cl4160.16 (3)C7—C8—H8A109.5
Cl1—Cu1—Cl490.46 (3)C7—C8—H8B109.5
Cl3—Cu1—Cl490.60 (3)H8A—C8—H8B109.5
Cl5—Cu2—Cl5i176.78 (4)C7—C8—H8C109.5
Cl5—Cu2—Cl6i89.66 (2)H8A—C8—H8C109.5
Cl5i—Cu2—Cl6i90.34 (2)H8B—C8—H8C109.5
Cl5—Cu2—Cl690.34 (2)C11—N3—C10114.3 (2)
Cl5i—Cu2—Cl689.66 (2)C11—N3—H3C110 (2)
Cl6i—Cu2—Cl6179.81 (4)C10—N3—H3C112 (2)
Cl8—Cu3—Cl8ii146.10 (4)C11—N3—H3D108 (2)
Cl8—Cu3—Cl794.66 (2)C10—N3—H3D110 (2)
Cl8ii—Cu3—Cl795.17 (2)H3C—N3—H3D102 (3)
Cl8—Cu3—Cl7ii95.17 (2)C10—C9—H9A109.5
Cl8ii—Cu3—Cl7ii94.66 (2)C10—C9—H9B109.5
Cl7—Cu3—Cl7ii145.83 (4)H9A—C9—H9B109.5
C2—N1—C3114.9 (2)C10—C9—H9C109.5
C2—N1—H1A108.0 (18)H9A—C9—H9C109.5
C3—N1—H1A109.8 (18)H9B—C9—H9C109.5
C2—N1—H1B109.9 (19)N3—C10—C9110.7 (2)
C3—N1—H1B109 (2)N3—C10—H10A109.5
H1A—N1—H1B104 (3)C9—C10—H10A109.5
C2—C1—H1C109.5N3—C10—H10B109.5
C2—C1—H1D109.5C9—C10—H10B109.5
H1C—C1—H1D109.5H10A—C10—H10B108.1
C2—C1—H1E109.5N3—C11—C12111.0 (2)
H1C—C1—H1E109.5N3—C11—H11A109.4
H1D—C1—H1E109.5C12—C11—H11A109.4
N1—C2—C1110.3 (2)N3—C11—H11B109.4
N1—C2—H2A109.6C12—C11—H11B109.4
C1—C2—H2A109.6H11A—C11—H11B108.0
N1—C2—H2B109.6C11—C12—H12A109.5
C1—C2—H2B109.6C11—C12—H12B109.5
H2A—C2—H2B108.1H12A—C12—H12B109.5
N1—C3—C4110.7 (2)C11—C12—H12C109.5
N1—C3—H3A109.5H12A—C12—H12C109.5
C4—C3—H3A109.5H12B—C12—H12C109.5
N1—C3—H3B109.5C15—N4—C14115.4 (2)
C4—C3—H3B109.5C15—N4—H4D111 (2)
H3A—C3—H3B108.1C14—N4—H4D106.8 (19)
C3—C4—H4A109.5C15—N4—H4E112 (2)
C3—C4—H4B109.5C14—N4—H4E106 (2)
H4A—C4—H4B109.5H4D—N4—H4E105 (3)
C3—C4—H4C109.5C14—C13—H13A109.5
H4A—C4—H4C109.5C14—C13—H13B109.5
H4B—C4—H4C109.5H13A—C13—H13B109.5
C6—N2—C7114.1 (2)C14—C13—H13C109.5
C6—N2—H2C110 (2)H13A—C13—H13C109.5
C7—N2—H2C109 (2)H13B—C13—H13C109.5
C6—N2—H2D109 (2)N4—C14—C13110.6 (2)
C7—N2—H2D108 (2)N4—C14—H14A109.5
H2C—N2—H2D106 (3)C13—C14—H14A109.5
C6—C5—H5A109.5N4—C14—H14B109.5
C6—C5—H5B109.5C13—C14—H14B109.5
H5A—C5—H5B109.5H14A—C14—H14B108.1
C6—C5—H5C109.5N4—C15—C16110.9 (2)
H5A—C5—H5C109.5N4—C15—H15A109.5
H5B—C5—H5C109.5C16—C15—H15A109.5
N2—C6—C5110.6 (2)N4—C15—H15B109.5
N2—C6—H6A109.5C16—C15—H15B109.5
C5—C6—H6A109.5H15A—C15—H15B108.0
N2—C6—H6B109.5C15—C16—H16A109.5
C5—C6—H6B109.5C15—C16—H16B109.5
H6A—C6—H6B108.1H16A—C16—H16B109.5
N2—C7—C8110.9 (2)C15—C16—H16C109.5
N2—C7—H7A109.5H16A—C16—H16C109.5
C8—C7—H7A109.5H16B—C16—H16C109.5
C3—N1—C2—C1173.6 (2)C11—N3—C10—C9177.6 (2)
C2—N1—C3—C4178.9 (2)C10—N3—C11—C12179.6 (2)
C7—N2—C6—C5179.7 (2)C15—N4—C14—C13179.8 (2)
C6—N2—C7—C8174.1 (2)C14—N4—C15—C16176.0 (2)
Symmetry codes: (i) x+1, y+1, z; (ii) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···Cl5iii0.84 (3)2.74 (3)3.316 (2)128 (2)
N1—H1A···Cl6iv0.84 (3)2.53 (3)3.323 (2)158 (2)
N1—H1B···Cl10.96 (3)2.23 (3)3.192 (2)178 (3)
N2—H2C···Cl2v0.84 (3)2.53 (3)3.316 (2)155 (3)
N2—H2C···Cl3v0.84 (3)2.72 (3)3.319 (3)129 (2)
N2—H2D···Cl40.91 (3)2.28 (3)3.180 (2)171 (3)
N3—H3C···Cl70.82 (3)2.39 (3)3.209 (3)176 (3)
N3—H3D···Cl30.92 (3)2.53 (3)3.383 (2)154 (3)
N3—H3D···Cl40.92 (3)2.56 (3)3.198 (3)127 (2)
N4—H4D···Cl7vi0.82 (3)2.93 (3)3.374 (3)116 (2)
N4—H4D···Cl8vii0.82 (3)2.40 (3)3.202 (3)167 (2)
N4—H4E···Cl50.86 (3)2.47 (3)3.283 (2)159 (3)
N4—H4E···Cl60.86 (3)2.75 (3)3.311 (3)125 (2)
Symmetry codes: (iii) x+1, y+1, z+1; (iv) x, y, z+1; (v) x1/2, y+1/2, z+1; (vi) x1/2, y+1/2, z; (vii) x+1/2, y+1/2, z.
Mean plane deviations for [CuCl4]2- anions (Å) top
*Because these pairs of atoms are symmetry related by a twofold axis, deviations are identical.
AtomDeviationAtomDeviationAtomDeviation
Cu10.0091 (4)Cu20.0239 (5)Cu3-0.0021 (5)
Cl10.3740 (4)Cl5/Cl5i*-0.0397 (6)Cl7/Cl7ii*0.6583 (5)
Cl2-0.3745 (4)Cl6/Cl6i*0.0277 (6)Cl8/Cl8ii*-0.6573 (6)
Cl30.3769 (4)
Cl4-0.3854 (4)
r.m.s. deviation0.33790.03240.5883
Symmetry codes: (i) -x+1, -y+1, z; (ii) -x+1, -y, z.
 

Acknowledgements

The authors would like to thank the University of Notre Dame for instrument support. The Weber Foundation, Thermo-Fisher Scientific, Kimble-Chase Life Sciences, and Hamilton Company are also gratefully acknowledged for funding support.

References

First citationAmberger, B. & Savji, N. (2008). https://www3.amherst.edu/thoughts/contents/amberger-thermochromism. html  Google Scholar
First citationBruker (2014). APEX2, SAINT and SADABS. Bruker–Nonius AXS Inc. Madison, Wisconsin, USA.  Google Scholar
First citationChandler, N. (2012). https://electronics.howstuffworks.com/gadgets/other-gadgets/ thermochromic-ink5.html.  Google Scholar
First citationChoi, S. & Larrabee, J. A. (1989). J. Chem. Educ. 66, 774–776.  CrossRef CAS Google Scholar
First citationDesiraju, G. R. (2002). Acc. Chem. Res. 35, 565–573.  Web of Science CrossRef PubMed CAS Google Scholar
First citationDolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationGroom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662–671.  Web of Science CSD CrossRef CAS Google Scholar
First citationJeffrey, G. (1997). In An Introduction to Hydrogen Bonding. Oxford University Press. Oxford, England.  Google Scholar
First citationMuthyala, R. (1997). In Chemistry and Applications of Leuco Dyes. New York: Plenum Press.  Google Scholar
First citationRoberts, S. A., Bloomquist, D. R., Willett, R. D. & Dodgen, H. W. (1981). J. Am. Chem. Soc. 103, 2603–2610.  CSD CrossRef CAS Web of Science Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationVan Oort, M. J. (1988). J. Chem. Educ. 65, 84–84.  CrossRef CAS Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWhite, M. A. & LeBlanc, M. (1999). J. Chem. Educ. 76, 1201–1205.  CrossRef CAS Google Scholar
First citationYang, L., Powell, D. R. & Houser, R. P. (2007). Dalton Trans. pp. 955–964.  Web of Science CSD CrossRef PubMed CAS Google Scholar

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