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Dicaesium penta­cyano­tricuprate(I), Cs2Cu3(CN)5

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aSchool of Chemistry, University of Reading, Reading, Berkshire RG6 6AD, England
*Correspondence e-mail: a.m.chippindale@rdg.ac.uk

(Received 22 May 2006; accepted 30 May 2006; online 9 June 2006)

Cs2Cu3(CN)5 has a layered structure consisting of [Cu3(CN)5]2− sheets stacked in an ABAB fashion along the c axis, with Cs+ cations lying between the sheets. The sheets are generated by linking –(CuCN)– chains, in which the C≡N groups are ordered, via [Cu(CN)3]2− units. The two bridging cyanide groups of each [Cu(CN)3]2− unit show partial `head-to-tail' disorder of C and N, whilst the third C≡N group is terminal and ordered with C bonded to Cu.

Comment

Copper(I) cyanide frameworks, like those of other transition-metal cyanides, can be viewed as constructed from M(CN)x structural building blocks. For copper(I), a range of potential building blocks are known, including simple species, such as linear [Cu(CN)2], trigonal [Cu(CN)3]2− and tetra­hedral [Cu(CN)4]3− units, and larger fragments, such as –(CuCN)– chains. These units have well defined geometries and can be assembled to form new solids by combining with themselves, in association with charge-balancing species where necessary, or with other complex metal ions or organic species, e.g. Lewis bases such as amines, to generate one-, two- and three-dimensional frameworks.

The present work is a continuation of our investigations of copper(I) cyanide materials prepared in the presence of alkali-metal cations (Chippindale et al., 2004[Chippindale, A. M., Hibble, S. J. & Cowley, A. R. (2004). Inorg. Chem. 44, 8040-8048.]; Pohl et al., 2006[Pohl, A. H., Chippindale, A. M. & Hibble, S. J. (2006). Solid State Sci. 8, 379-387.]). Cs2Cu3(CN)5 reported here has the same layer structure as K2Cu3(CN)5, prepared previously in acetonitrile under solvothermal conditions (Pohl et al., 2006[Pohl, A. H., Chippindale, A. M. & Hibble, S. J. (2006). Solid State Sci. 8, 379-387.]).

The layer structure of Cs2Cu3(CN)5 can be described in terms of –(Cu2CN)– chains running along the b axis and linked through bridging [Cu1(CN)3]2− units to generate a network of (CuCN)8 rings within the layers. The layers stack in an ABAB fashion along the c axis (Fig. 1[link]). Cs+ cations lie between the layers bonded to 12 cyanide groups, with Cs—C/N distances in the range 3.11 (2)–3.58 (3) Å.

There are two crystallographically distinct Cu atoms, both of which have approximately trigonal-planar coordination (Fig. 2[link]). Atom Cu1, on a special position of site symmetry 2, is bonded to two equivalent bridging cyanide groups, Z3≡Z4, through the Z4 ends of the groups. The Z3≡Z4 unit shows partial `head-to-tail' disorder, as determined by refinement, with Z3 having occupancy 0.78 (4) for C3 and 0.22 (4) for N3 and Z4 having occupancy 0.22 (4) for C4 and 0.78 (4) for N4. The coordination around Cu1 is completed by a third cyanide group, C1≡N1, bonded as a terminal group to Cu1 through C1. Atom Cu2, sited on a general position, bonds directly to C2, N2 and Z3 and is also approximately trigonal planar, although the geometry around Cu2 is less regular than that found for Cu1. The refinement of site occupancies for the cyanide group C2≡N2 indicates that the C and N atoms are fully ordered. The greater deviation from linearity of the Cu2—N2≡C2 angle compared with the Cu2—C2≡N2 angle in Cu2—C2≡N2—Cu2iii (symmetry code as in Table 1[link]) confirms this assignment: strong ππ inter­actions between a metal and the C end of a cyanide usually result in a smaller deviation from linearity of the M—C—N angle than the M′—N—C angle (Vahrenkamp et al., 1997[Vahrenkamp, H., Geiss, A. & Richardson, G. N. (1997). J. Chem. Soc. Dalton Trans. pp. 3643-3651.]).

[Figure 1]
Figure 1
A projection of the crystal structure along the c axis, showing layers stacked as ABAB with Cs+ cations between the layers. Key: Cu atoms are black, Cs orange, C green, N blue and Z (C or N of a disordered cyanide group) cyan.
[Figure 2]
Figure 2
A (Cu(CN)8 ring from the [Cu3(CN)5]2− layer, showing the approximately trigonal-planar coordination of atoms Cu1 and Cu2. The terminal cyanide group C1≡N1 points into the centre of the ring. Key as given for Fig. 1[link]. Displacement ellipsoids are drawn at the 50% probability level.

Experimental

Crystals of Cs2Cu3(CN)5 were prepared at 293 K. KCN (1.30 g, 20.0 mmol), CuCN (0.46 g, 5.1 mmol) and CsNO3 (1.94 g, 10.0 mmol) were dissolved in deionized water (15 ml) to form a colourless solution. On addition of 1 M H2SO4 (7.4 ml), a white precipitate formed immediately. This was subsequently identified as Cs2Cu3(CN)5 using powder X-ray diffraction. The precipitate was allowed to stand in the solution at room temperature, and after three weeks colourless recta­ngular blocks of Cs2Cu3(CN)5 had grown. The crystals were filtered off, washed with water and allowed to dry in the air. A powder X-ray diffraction pattern of the ground crystals confirmed that the product was monophasic. IR data (Nujol mull): ν(C≡N) 2140 (m), 2104 (s), 2098 (s) cm−1.

Crystal data
  • Cs2Cu3(CN)5

  • Mr = 586.54

  • Monoclinic, C 2/c

  • a = 17.8156 (9) Å

  • b = 8.0962 (15) Å

  • c = 8.3890 (8) Å

  • β = 91.771 (8)°

  • V = 1209.4 (3) Å3

  • Z = 4

  • Dx = 3.221 Mg m−3

  • Mo Kα radiation

  • μ = 11.13 mm−1

  • T = 150 K

  • Block, colourless

  • 0.24 × 0.12 × 0.08 mm

Data collection
  • Oxford Gemini S Ultra diffractometer

  • ω/2θ scans

  • Absorption correction: multi-scan (ABSPACK; Oxford Diffraction, 2006[Oxford Diffraction (2006). ABSPACK and CrysAlisPro (Version 171.29.8). Oxford Diffraction Ltd, Abingdon, Oxford, England.]) Tmin = 0.21, Tmax = 0.41

  • 9301 measured reflections

  • 1343 independent reflections

  • 1123 reflections with I > 3σ(I)

  • Rint = 0.021

  • θmax = 28.5°

Refinement
  • Refinement on F

  • R[F2 > 2σ(F2)] = 0.017

  • wR(F2) = 0.020

  • S = 1.08

  • 1123 reflections

  • 71 parameters

  • Modified Chebychev polynomial (Watkin, 1994[Watkin, D. J. (1994). Acta Cryst. A50, 411-437.]; Prince, 1982[Prince, E. (1982). Mathematical Techniques in Crystallography and Materials Science, pp. 79-82. New York: Springer-Verlag.]) with coefficients: 16.0, −11.9, 11.5, 1.63

  • (Δ/σ)max = 0.003

  • Δρmax = 0.88 e Å−3

  • Δρmin = −0.70 e Å−3

Table 1
Selected geometric parameters (Å, °)

Z denotes a disordered cyanide group.

Cu1—C1 1.915 (4)
Cu1—Z4 1.951 (3)
Cu2—C2 1.912 (3)
Cu2—N2i 2.016 (3)
Cu2—Z3 1.916 (3)
N1—C1 1.151 (6)
N2—C2 1.145 (4)
Z3—Z4 1.156 (4)
Z4ii—Cu1—Z4 114.60 (16)
Z4—Cu1—C1 122.70 (8)
N2i—Cu2—Z3 111.60 (11)
N2i—Cu2—C2 110.50 (12)
C2—Cu2—Z3 137.26 (12)
Cu2iii—N2—C2 160.7 (3)
Cu2—Z3—Z4 173.8 (3)
Cu1—Z4—Z3 168.7 (3)
N1—C1—Cu1 180
N2—C2—Cu2 176.7 (3)
Symmetry codes: (i) [-x+{\script{3\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (ii) [-x+1, y, -z+{\script{1\over 2}}]; (iii) [-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}].

The orientations of the three distinct C≡N groups were investigated as follows. Each C≡N was modelled as ZxZy with starting values for the occupancies of both Zx and Zy set to (0.5 C + 0.5 N). The site occupancies were then refined subject to the constraints that the total occupancy for each site was 1.00 and the displacement parameters of C and N on the same site were equal. Cyanide groups C1≡N1 and C2≡N2 were found to be fully ordered and the occupancies of these groups were fixed in subsequent refinements. The occupancies in the remaining bridging Z3≡Z4 group have refined values for Z3 of 0.78 (4) for C3 and 0.22 (4) for N3, and for Z4 of 0.22 (4) for C4 and 0.78 (4) for N4.

Data collection: CrysAlisPro, (Oxford Diffraction, 2006[Oxford Diffraction (2006). ABSPACK and CrysAlisPro (Version 171.29.8). Oxford Diffraction Ltd, Abingdon, Oxford, England.]); cell refinement: CrysAlisPro; data reduction: CrysAlisPro; program(s) used to solve structure: SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003[Betteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, C. K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487.]); molecular graphics: CAMERON (Watkin et al., 1996[Watkin, D. J., Prout, C. K. & Pearce, L. J. (1996). CAMERON. Chemical Crystallography Laboratory, University of Oxford, England.]); software used to prepare material for publication: CRYSTALS.

Supporting information


Computing details top

Data collection: CrysAlis PRO, (Oxford Diffraction, 2006); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS.

dicaesium pentacyanocuprate(I) top
Crystal data top
Cs2Cu3(CN)5F(000) = 1048
Mr = 586.54Dx = 3.221 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1341 reflections
a = 17.8156 (9) Åθ = 3–28°
b = 8.0962 (15) ŵ = 11.13 mm1
c = 8.3890 (8) ÅT = 150 K
β = 91.771 (8)°Block, colourless
V = 1209.4 (3) Å30.24 × 0.12 × 0.08 mm
Z = 4
Data collection top
Oxford Diffraction Gemini S Ultra
diffractometer
1123 reflections with I > 3σ(I)
Graphite monochromatorRint = 0.021
ω/2θ scansθmax = 28.5°, θmin = 2.8°
Absorption correction: multi-scan
(ABSPACK; Oxford Diffraction, 2006)
h = 2323
Tmin = 0.21, Tmax = 0.41k = 1010
9301 measured reflectionsl = 1110
1343 independent reflections
Refinement top
Refinement on F0 restraints
Least-squares matrix: fullPrimary atom site location: structure-invariant direct methods
R[F2 > 2σ(F2)] = 0.017 Modified Chebychev polynomial (Watkin, 1994; Prince, 1982) with coefficients: 16.0 -11.9 11.5 1.63
wR(F2) = 0.020(Δ/σ)max = 0.003
S = 1.08Δρmax = 0.88 e Å3
1123 reflectionsΔρmin = 0.70 e Å3
71 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cu10.50.07756 (6)0.250.0271
Cu20.69499 (2)0.16705 (4)0.61633 (5)0.0241
Cs10.61328 (1)0.31446 (2)0.58176 (2)0.0224
N10.50000.4562 (5)0.250.0292
N20.74397 (14)0.4701 (3)0.8103 (3)0.0261
N30.61620 (16)0.1048 (3)0.4678 (3)0.02370.22 (4)
N40.57032 (15)0.0526 (3)0.3812 (3)0.02630.78 (4)
C10.50000.3140 (5)0.250.0216
C20.72384 (16)0.3592 (4)0.7357 (4)0.0235
C30.61620 (16)0.1048 (3)0.4678 (3)0.02370.78 (4)
C40.57032 (15)0.0526 (3)0.3812 (3)0.02630.22 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0299 (3)0.0204 (2)0.0305 (3)0.00000.0086 (2)0.0000
Cu20.02514 (18)0.01995 (18)0.0268 (2)0.00171 (14)0.00494 (14)0.00083 (13)
Cs10.02314 (11)0.02181 (11)0.02193 (11)0.00201 (6)0.00309 (6)0.00117 (6)
N10.0277 (18)0.0277 (19)0.0324 (19)0.00000.0043 (15)0.0000
N20.0244 (12)0.0211 (12)0.0325 (13)0.0019 (10)0.0032 (10)0.0004 (10)
N30.0247 (14)0.0215 (13)0.0250 (15)0.0015 (11)0.0019 (11)0.0025 (10)
N40.0273 (13)0.0240 (12)0.0275 (13)0.0039 (11)0.0021 (11)0.0009 (11)
C10.0188 (17)0.024 (2)0.0221 (19)0.00000.0046 (14)0.0000
C20.0206 (13)0.0196 (12)0.0300 (15)0.0009 (11)0.0048 (10)0.0015 (11)
C30.0247 (14)0.0215 (13)0.0250 (15)0.0015 (11)0.0019 (11)0.0025 (10)
C40.0273 (13)0.0240 (12)0.0275 (13)0.0039 (11)0.0021 (11)0.0009 (11)
Geometric parameters (Å, º) top
Cu1—C11.915 (4)Cu2—Z31.916 (3)
Cu1—Z41.951 (3)N1—C11.151 (6)
Cu1—Z4i1.951 (3)N2—C21.145 (4)
Cu2—C21.912 (3)Z3—Z41.156 (4)
Cu2—N2ii2.016 (3)
Z4i—Cu1—Z4114.60 (16)Cu2iii—N2—C2160.7 (3)
Z4i—Cu1—C1122.70 (8)Cu2—Z3—Z4173.8 (3)
Z4—Cu1—C1122.70 (8)Cu1—Z4—Z3168.7 (3)
N2ii—Cu2—Z3111.60 (11)N1—C1—Cu1180
N2ii—Cu2—C2110.50 (12)N2—C2—Cu2176.7 (3)
C2—Cu2—Z3137.26 (12)
Symmetry codes: (i) x+1, y, z+1/2; (ii) x+3/2, y+1/2, z+3/2; (iii) x+3/2, y1/2, z+3/2.
 

Acknowledgements

The authors thank the EPSRC for grants in support of a single-crystal CCD diffractometer and a Studentship for AHP. AMC thanks the Leverhulme Trust for a Research Fellowship.

References

First citationAltomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.  CrossRef Web of Science IUCr Journals Google Scholar
First citationBetteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, C. K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487.  Web of Science CrossRef IUCr Journals Google Scholar
First citationChippindale, A. M., Hibble, S. J. & Cowley, A. R. (2004). Inorg. Chem. 44, 8040–8048.  CrossRef Google Scholar
First citationOxford Diffraction (2006). ABSPACK and CrysAlisPro (Version 171.29.8). Oxford Diffraction Ltd, Abingdon, Oxford, England.  Google Scholar
First citationPohl, A. H., Chippindale, A. M. & Hibble, S. J. (2006). Solid State Sci. 8, 379–387.  CrossRef CAS Google Scholar
First citationPrince, E. (1982). Mathematical Techniques in Crystallography and Materials Science, pp. 79–82. New York: Springer-Verlag.  Google Scholar
First citationVahrenkamp, H., Geiss, A. & Richardson, G. N. (1997). J. Chem. Soc. Dalton Trans. pp. 3643–3651.  CrossRef Web of Science Google Scholar
First citationWatkin, D. J. (1994). Acta Cryst. A50, 411–437.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationWatkin, D. J., Prout, C. K. & Pearce, L. J. (1996). CAMERON. Chemical Crystallography Laboratory, University of Oxford, England.  Google Scholar

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