Search tips
Search criteria 


Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
Acta Crystallogr Sect E Struct Rep Online. 2008 September 1; 64(Pt 9): m1145.
Published online 2008 August 9. doi:  10.1107/S1600536808025208
PMCID: PMC2960579

Hexacarbonyl­technetium(I) perchlorate


The title compound, [Tc(CO)6]ClO4, was synthesized by the reaction of [TcCl(CO)5] with AgClO4, followed by acidification with HClO4 under a CO atmosphere. The [Tc(CO)6]+ cation has close to idealized octa­hedral geometry, with the bond angles between cis-CO groups close to 90° and the Tc—C bond lengths in the range 2.025 (3)–2.029 (3)Å. The perchlorate anion is disordered over two crystallographically equivalent half-occupied positions. The Tc atom in the [Tc(CO)6]+ cation is located on an inversion centre.

Related literature

For the first report on the [Tc(CO)6]+ cation, see: Hieber et al. (1965 [triangle]). For related literature, see: Aebischer et al. (2000 [triangle]); Alberto et al. (1996 [triangle], 1998 [triangle]); Baturin et al. (1994a [triangle],b [triangle]); Grigor’ev et al. (1997a [triangle],b [triangle]); Miroslavov et al. (2008a [triangle],b [triangle]); Schwochau (2000 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-m1145-scheme1.jpg


Crystal data

  • [Tc(CO)6]ClO4
  • M r = 366.42
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-m1145-efi1.jpg
  • a = 13.227 (4) Å
  • b = 6.8002 (18) Å
  • c = 13.616 (3) Å
  • β = 112.56 (2)°
  • V = 1131.0 (5) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 1.55 mm−1
  • T = 293 (2) K
  • 0.20 × 0.18 × 0.10 mm

Data collection

  • Stoe IPDS-2 diffractometer
  • Absorption correction: integration (X-RED and X-SHAPE; Stoe & Cie, 2005 [triangle]) T min = 0.620, T max = 0.723
  • 4935 measured reflections
  • 1508 independent reflections
  • 1224 reflections with I > 2σ(I)
  • R int = 0.035


  • R[F 2 > 2σ(F 2)] = 0.030
  • wR(F 2) = 0.067
  • S = 1.06
  • 1508 reflections
  • 99 parameters
  • Δρmax = 0.32 e Å−3
  • Δρmin = −0.44 e Å−3

Data collection: X-AREA (Stoe & Cie, 2007 [triangle]); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2005 [triangle]); program(s) used to solve structure: SHELXL97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ATOMS (Dowty, 2000 [triangle]); software used to prepare material for publication: publCIF (Westrip, 2008 [triangle]).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808025208/fj2134sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808025208/fj2134Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report


The study was financially supported in part by the Russian Foundation for Basic Research (project No. 07–03-00089 - a) and the Russian Federation Ministry of Science and Education (project No. RNP

supplementary crystallographic information


Among technetium(I) carbonyl complexes, the highest carbonyl, [Tc(CO)6]+ cation, is the least studied compared to penta-, tetra-, and especially tricarbonyl complexes (Schwochau, 2000). No data on the crystal structure of its salts are available. More detailed study of this cation is significant for the development of the coordination chemistry of technetium (and d block as a whole). The first report on the [Tc(CO)6]+ cation is dated by Hieber et al., 1965 prepared this species in the form of the solid compound [Tc(CO)6][AlCl4] by the solid-phase reaction of [TcCl(CO)5] with AlCl3 under high CO pressure (300 atm) at 363 K (Heiber et al., 1965). The product was characterized by chemical analysis, and the cation appeared to be stable in solutions. Relatively recently (Aebischer et al., 2000) observed successive formation of higher technetium carbonyls [Tc(CO)n(H2O)6–n]+ (n = 4–6) in aqueous solution (2 M HClO4) from the complex [Tc(CO)3(H2O)3]+ at room temperature and moderately high CO pressure (about 50 atm), after removal of chloride ions. The reaction progress was monitored by the 99Tc and 13C NMR. The relative content of the [Tc(CO)6]+ cation in the mixture of technetium carbonyl species was low, and no solid salt of this cation was isolated. Here we report on the synthesis and crystal structure of hexacarbonyltechnetium(I) perchlorate, [Tc(CO)6]ClO4.


Pentacarbonyltechnetium chloride [TcCl(CO)5] (SU Inventor's Certificate 1512003) was dissolved in boiled water, and a stoichiometric amount of AgClO4 was added after cooling to remove chloride ions interfering with the synthesis (Miroslavov et al., 2008a). The resulting solution was acidified with HClO4 to a concentration of 2 M and treated with CO in a pressure vessel (443 K, 150 atm, 1 h). After completing the reaction and removing the excess of CO, the reaction system consisted of an aqueous solution and a colorless crystalline precipitate. The precipitate was separated, washed with water and methylene chloride (to remove an impurity of [TcCl(CO)5] (Miroslavov et al., 2008a)), and dried in air. The product was identified as [Tc(CO)6]ClO4. Some of the crystals appeared to be suitable for an X-ray diffraction analysis. 99Tc NMR(CH3OH): -1924 p.p.m.. IR (CH3CN): nCO 2095 cm-1. Found Tc, %: 27.12. C6ClO10Tc. Calculated Tc, %: 27.01. The IR spectrum was recorded on a Shimadzu FTIR 8700 spectrophotometer. The 99Tc NMR spectrum was taken on a Bruker WP-200 spectrometer.


The crystal structure of [Tc(CO)6]ClO4 contains one symmetrically independent Tc+ cation octahedrally coordinated by six carbon atoms (Figs. 1, 2). The Tc—C=O fragments are linear to within 3°. The coordination polyhedron of technetium in the [Tc(CO)6]+ cation is close to an ideal octahedron, with the bond angles between cis-CO groups equal to 90° (within ±1.5°) and the Tc–C bond lengths in the range of 2.025–2.029 Å. These distances are significantly (by 0.1–0.15 Å) longer than the Tc–C distances in trans-OC–Tc–σ donor fragments, e.g.: [TcI(CO)5](Tc–Ctrans-I) 1.938 (Grigor'ev et al., 1997a), [TcI(CO)4]2 (Tc–Ctrans-I) 1.89–1.92 (Grigor'ev et al., 1997b), [TcCl(CO)3]4 1.903 (Baturin et al., 1994a), [TcBr(CO)3(en)] 1.882–1.889 (Baturin et al., 1994b), [Tc(OH)(CO)3]4 1.886–1.905 Å (Alberto et al., 1998). At the same time, they are only slightly longer than the Tc–C distances in trans-OC–Tc–π acceptor fragments of other structurally examined complexes (π acceptor is another CO group, PPh3, or ButNC): [Tc(CO)5(ButNC)]ClO4 1.999–2.022 (Miroslavov et al., 2008b), [Tc(CO)5(PPh3)]CF3SO3 1.985–2.019 (Alberto et al., 1998) (in these two compounds, the lengths of the equatorial and axial Tc–CO bonds are similar), [fac-Tc(CO)3(ButNC)3]NO3 1.963–1.975 (Alberto et al., 1996) [TcI(CO)5] (Tc–C~trans-CO~) 2.015 (Grigor'ev et al., 1997a), [TcI(CO)4]2 (Tc–Ctrans-CO) 1.98–2.01 Å (Grigor'ev et al., 1997b). The large difference between the Tc–CO bond lengths in cases when the transposition to the CO group is occupied by a π acceptor or a σ donor can be attributed to the trans effect (competition between the π acceptors arranged trans to each other for the same occupied d orbital of the metal ion). A certain cis effect, however, also takes place, because the Tc–CO bonds in the [Tc(CO)6]+ cation are somewhat longer than the Tc–CO bonds in trans-OC–Tc–CO fragments of complexes containing in cis positions ligands that are σ donors or π acceptors weaker than CO.

The Cl atom in the structure of [Tc(CO)6]ClO4 is tetrahedrally coordinated by four O atoms (mean Cl–O distance is 1.403 Å). The perchlorate anion is disordered over two crystallographically equivalent half-occupied positions (Fig. 2) with the total site-occupation factor (s.o.f.) equal to 1.0. The central atoms of [Tc(CO)6]+ octahedra and [ClO4]- tetrahedra (Tc and Cl respectively) form a distorted NaCl-type lattice oriented along aNaCl [110], bNaCl [10–1], cNaCl [-110] (Fig. 3).


Fig. 1.
View of the [Tc(CO)6]+cation (a) and one component of the disordered perchlorate anion (b) in the structure of [Tc(CO)6]ClO4. Thermal ellipsoids are drawn at the 50% probability level.
Fig. 2.
Crystal structure of [Tc(CO)6]ClO4. Tc atoms are dark-grey, O atoms are grey, Cl atoms are light-grey, and C atoms are white circles.
Fig. 3.
Relationship of title structure to NaCl structure.

Crystal data

[Tc(CO)6]ClO4F000 = 704
Mr = 366.42Dx = 2.152 Mg m3
Monoclinic, C2/cMo Kα radiation λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 5446 reflections
a = 13.227 (4) Åθ = 2.0–29.6º
b = 6.8002 (18) ŵ = 1.55 mm1
c = 13.616 (3) ÅT = 293 (2) K
β = 112.56 (2)ºPrism, colorless
V = 1131.0 (5) Å30.20 × 0.18 × 0.10 mm
Z = 4

Data collection

Stoe IPDS-2 diffractometer1508 independent reflections
Radiation source: fine-focus sealed tube1224 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.035
Detector resolution: 6.67 pixels mm-1θmax = 29.2º
T = 293(2) Kθmin = 3.2º
rotation method scansh = −18→18
Absorption correction: integration(X-RED and X-SHAPE; Stoe & Cie, 2005)k = −9→8
Tmin = 0.620, Tmax = 0.723l = −18→18
4935 measured reflections


Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: full  w = 1/[σ2(Fo2) + (0.0289P)2 + 1.543P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.031(Δ/σ)max < 0.001
wR(F2) = 0.067Δρmax = 0.32 e Å3
S = 1.06Δρmin = −0.44 e Å3
1508 reflectionsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
99 parametersExtinction coefficient: 0.0043 (12)
Primary atom site location: structure-invariant direct methods

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/UeqOcc. (<1)
Tc10.25000.25000.00000.03673 (14)
C10.2509 (2)0.1350 (5)0.1375 (2)0.0484 (7)
C20.3021 (2)−0.0119 (5)−0.0345 (2)0.0446 (6)
C30.4088 (2)0.3328 (5)0.0721 (3)0.0501 (7)
O10.3312 (2)−0.1557 (4)−0.0529 (2)0.0632 (6)
O20.49658 (19)0.3762 (4)0.1078 (3)0.0774 (8)
O30.2481 (2)0.0685 (5)0.2111 (2)0.0778 (8)
O40.0932 (2)−0.2268 (5)−0.1933 (3)0.0814 (9)
O50.503 (3)0.0179 (9)0.2724 (16)0.109 (7)0.50
O60.5401 (5)−0.1423 (12)0.1398 (5)0.0856 (18)0.50
Cl10.50996 (15)−0.1697 (2)0.22853 (14)0.0480 (4)0.50

Atomic displacement parameters (Å2)

Tc10.03421 (17)0.04318 (19)0.03316 (17)0.00255 (14)0.01331 (11)−0.00340 (15)
C10.0481 (15)0.0592 (18)0.0423 (16)0.0126 (13)0.0222 (12)0.0041 (13)
C20.0403 (13)0.0519 (15)0.0404 (14)0.0037 (12)0.0141 (11)−0.0028 (12)
C30.0418 (14)0.0527 (15)0.0545 (18)0.0005 (13)0.0172 (13)−0.0074 (14)
O10.0693 (15)0.0567 (14)0.0658 (16)0.0148 (12)0.0284 (12)−0.0076 (12)
O20.0433 (12)0.0782 (18)0.105 (2)−0.0091 (12)0.0216 (13)−0.0225 (16)
O30.0830 (18)0.105 (2)0.0609 (16)0.0297 (16)0.0444 (14)0.0249 (16)
O40.0566 (14)0.096 (2)0.087 (2)−0.0202 (14)0.0229 (14)−0.0261 (16)
O50.077 (4)0.074 (3)0.155 (19)−0.002 (8)0.021 (12)−0.052 (8)
O60.072 (3)0.120 (5)0.061 (3)−0.019 (3)0.021 (3)0.019 (4)
Cl10.0366 (7)0.0512 (6)0.0497 (12)−0.0023 (6)0.0094 (6)−0.0015 (6)

Geometric parameters (Å, °)

Tc1—C1i2.025 (3)O5—O5iv0.59 (4)
Tc1—C12.025 (3)O5—Cl1iv1.286 (8)
Tc1—C3i2.027 (3)O5—Cl11.428 (11)
Tc1—C32.027 (3)O6—Cl11.422 (6)
Tc1—C2i2.029 (3)O6—Cl1iv2.144 (6)
Tc1—C22.029 (3)Cl1—Cl1iv0.728 (3)
C1—O31.113 (4)Cl1—O5iv1.286 (8)
C2—O11.114 (4)Cl1—O4v1.393 (3)
C3—O21.113 (4)Cl1—O4iii1.444 (3)
O4—Cl1ii1.393 (3)Cl1—O6iv2.144 (6)
O4—Cl1iii1.444 (3)
C1i—Tc1—C1180.0 (2)O1—C2—Tc1179.6 (3)
C1i—Tc1—C3i91.27 (14)O2—C3—Tc1177.0 (3)
C1—Tc1—C3i88.73 (14)O5iv—Cl1—O4v124.7 (11)
C1i—Tc1—C388.73 (14)O4v—Cl1—O5107.0 (10)
C1—Tc1—C391.27 (14)O5iv—Cl1—O686.5 (11)
C3i—Tc1—C3180.0 (3)O4v—Cl1—O6108.6 (3)
C1i—Tc1—C2i89.61 (12)O5—Cl1—O6108.9 (9)
C1—Tc1—C2i90.39 (12)O5iv—Cl1—O4iii112.3 (14)
C3i—Tc1—C2i88.56 (12)O4v—Cl1—O4iii112.1 (3)
C3—Tc1—C2i91.44 (12)O5—Cl1—O4iii111.5 (13)
C1i—Tc1—C290.39 (12)O6—Cl1—O4iii108.6 (3)
C1—Tc1—C289.61 (12)O5iv—Cl1—O6iv80.9 (11)
C3i—Tc1—C291.44 (12)O4v—Cl1—O6iv79.2 (2)
C3—Tc1—C288.56 (12)O5—Cl1—O6iv58.6 (10)
C2i—Tc1—C2180.00 (17)O6—Cl1—O6iv167.4 (6)
O3—C1—Tc1177.6 (3)O4iii—Cl1—O6iv76.4 (2)

Symmetry codes: (i) −x+1/2, −y+1/2, −z; (ii) x−1/2, −y−1/2, z−1/2; (iii) −x+1/2, −y−1/2, −z; (iv) −x+1, y, −z+1/2; (v) x+1/2, −y−1/2, z+1/2.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FJ2134).


  • Aebischer, N., Schibli, R., Alberto, R. & Merbach, A. E. (2000). Angew. Chem. Int. Ed.39, 254–256. [PubMed]
  • Alberto, R., Schibli, R., Egli, A., Abram, U., Abram, S., Kaden, T. A. & Schubiger, P. A. (1998). Polyhedron, 17, 1133–1140.
  • Alberto, R., Schibli, R., Schubiger, P. A., Abram, U. & Kaden, T. A. (1996). Polyhedron, 15, 1079–1089.
  • Baturin, N. A., Grigor’ev, M. S., Kryuchkov, S. V., Miroslavov, A. E., Sidorenko, G. V. & Suglobov, D. N. (1994a). Radiochemistry, 36, 199–201.
  • Baturin, N. A., Grigor’ev, M. S., Kryuchkov, S. V., Miroslavov, A. E., Sidorenko, G. V. & Suglobov, D. N. (1994b). Radiochemistry, 36, 202–204.
  • Dowty, E. (2000). ATOMS Shape Software, Kingsport, Tennessee, USA.
  • Grigor’ev, M. S., Miroslavov, A. E., Sidorenko, G. V. & Suglobov, D. N. (1997a). Radiochemistry, 39, 204–206.
  • Grigor’ev, M. S., Miroslavov, A. E., Sidorenko, G. V. & Suglobov, D. N. (1997b). Radiochemistry, 39, 207–209.
  • Hieber, W., Lux, F. & Herget, C. Z. (1965). Naturforsch. Teil B, 20, 1159–1165.
  • Miroslavov, A. E., Levitskaya, E. M., Sidorenko, G. V., Lumpov, A. A., Suglobov, D. N., Gurzhiy, V. V. & Krivovichev, S. V. (2008a). Radiochemistry, 50 In the press.
  • Miroslavov, A. E., Lumpov, A. A., Sidorenko, G. V., Levitskaya, E. M., Gorshkov, N. I., Suglobov, D. N., Alberto, R., Braband, H., Gurzhiy, V. V., Krivovichev, S. V. & Tananaev, I. G. (2008b). J. Organomet. Chem.693, 4–10.
  • Schwochau, K. (2000). Technetium, Chemistry and Radiopharmaceutical Applications New York: Wiley-VCH.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Stoe & Cie (2005). X-RED and X-SHAPE Stoe & Cie GmbH, Darmstadt, Germany.
  • Stoe & Cie (2007). X-AREA Stoe & Cie GmbH, Darmstadt, Germany.
  • Westrip, S. P. (2008). publCIF In preparation.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography