trans-K3[TcO2(CN)4]

Chatterjee, S.; Del Negro, A.S.; Edwards, M.K.; Twamley, B.; Krause, J.A.; Bryan, S.A.

doi:10.1107/S1600536810028205

inorganic compounds

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ISSN: 2056-9890

Volume 66| Part 8| August 2010| Pages i61-i62

https://doi.org/10.1107/S1600536810028205

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trans-K₃[TcO₂(CN)₄]

Sayandev Chatterjee,^a Andrew S. Del Negro,^a Matthew K. Edwards,^a Brendan Twamley,^b Jeanette A. Krause ^c and Samuel A. Bryan ^a ^*

^aRadiochemical Processing Laboratory, Pacific Northwest National Laboratory, Richland, WA 99357, USA, ^bDepartment of Chemistry, University of Idaho, Moscow, ID 83844, USA, and ^cDepartment of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172, USA
^*Correspondence e-mail: sam.bryan@pnl.gov

(Received 8 July 2010; accepted 14 July 2010; online 21 July 2010)

The structure of the title compound, tripotassium trans-tetracyanidodioxidotechnetate(V), is isotypic with its Re analogue. The [TcO₂(CN)₄]³⁻ trans-tetracyanidodioxidotechnetate anion has a slightly distorted octahedral configuration. The Tc atom is located on a center of inversion and is bound to two O atoms in axial and to four cyanide ligands in equatorial positions. The Tc—O distance is consistent with a double-bond character. The two potassium cations, one located on a center of inversion and one in a general position, reside in octahedral or tetrahedral environments, respectively. K⋯O and K⋯N interactions occur in the 2.7877 (19)–2.8598 (15) Å range.

Related literature

The isotypic rhenate(V) analogue was reported by Fenn et al. (1971 ) (neutron study) and Murmann & Schlemper (1971 ) (X-ray study). For further information on dioxidotetracyanido anions of Tc and Re, see: Fackler et al. (1985 ); Kastner et al. (1982 , 1984 ); Kremer et al. (1997 ). Luminescence properties of Tc complexes were reported by Del Negro et al. (2005 , 2006 ). For further information on hydroxidooxidotetracyanido or aquaoxidotetracyanido anions of Tc and Re, see: Baldas et al. (1990 ); Purcell et al. (1989 , 1990 ). For general reviews on technetium structures, see: Bandoli et al. (2001 , 2006 ); Bartholoma et al. (2010 ); Tisato et al. (1994 ). Synthetic details were given by Trop et al. (1980 ). For a description of the Cambridge Structural Database, see: Allen (2002 ).

Experimental

Crystal data

K₃[TcO₂(CN)₄]
M_r = 351.38
Triclinic, $[P \overline 1]$
a = 6.2539 (6) Å
b = 6.9389 (6) Å
c = 7.4347 (7) Å
α = 108.305 (1)°
β = 109.816 (2)°
γ = 104.143 (1)°
V = 265.01 (4) Å³
Z = 1
Mo Kα radiation
μ = 2.51 mm⁻¹
T = 90 K
0.32 × 0.20 × 0.14 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2007 ) T_min = 0.490, T_max = 0.705
3949 measured reflections
1097 independent reflections
1064 reflections with > σ(I)
R_int = 0.072

Refinement

R[F² > 2σ(F²)] = 0.020
wR(F²) = 0.049
S = 1.09
1097 reflections
68 parameters
Δρ_max = 0.77 e Å⁻³
Δρ_min = −0.90 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Tc1—O1	1.7721 (12)
Tc1—C1	2.1423 (19)
Tc1—C2	2.145 (2)
N1—C1	1.150 (3)
N2—C2	1.151 (3)

N1—C1—Tc1	177.71 (16)
N2—C2—Tc1	172.74 (15)

Data collection: SMART (Bruker, 2006 ); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and DIAMOND (Brandenburg, 2010 ); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536810028205/wm2375sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810028205/wm2375Isup2.hkl

checkCIF report

Comment top

⁹⁹Tc is the most significant long-lived product of uranium fission. In addition to a long half-life (2.13x10⁵ yrs), it is readily water soluble, making it extremely mobile in the environment. This, coupled with its ability to form anionic species, causes major concern when considering long-term disposal of high-level radioactive waste. Thus, it is imperative to provide methods for chemical detection of ⁹⁹Tc. Under normal environmental conditions, ⁹⁹Tc composition is dominated by the pertechnetate anion (TcO₄^-) which lacks a characteristic spectral signature. This prevents its rapid, sensitive and economic in situ detection. In order to address this problem, our research is focused on designing a suitable sensor for the detection of TcO₄^-. The ultimate aim is to chemically convert the pertechnetate anion to an organic-ligated species that will have a readily characterizable spectral signature. As a first step to address this problem, our group has been able to identify several technetium complexes with long-lived excited states. Thus, the luminescence properties of technetium(V)-dioxidotetrapyridyl and technetium(II)-tris(1,2-bis(dimethylphosphino)ethane) were reported by Del Negro et al. (2005, 2006).

However, the significant dearth of Tc structures in general (Bandoli et al., 2001, 2006; Bartholoma et al., 2010; Tisato et al., 1994) has resulted in a substantial knowledge gap in the structures and bonding of technetium complexes, thereby preventing the correlation of the electronic properties with structural parameters. As a representative comparison, the Cambridge Structural Database (CSD, version 5.31; Allen, 2002) currently contains 21 dioxidotechnetium complexes compared to 141 structures reported for dioxidorhenium and dioxidomanganese complexes. In an attempt to bridge this gap, we are focusing on the structural characterization of a series of dioxidotechnetium(V) complexes. Herein, we report the structure of K₃[TcO₂(CN)₄], (I), a tetracyanidodioxidotechnetium(V) salt.

The unit cell of (I) is comprised of three K⁺ cations and one discrete [TcO₂(CN)₄]^3- anion. The configuration of the anion is shown in Fig. 1. The Tc atom (located on an inversion center) resides in an octahedral environment defined by two oxido and four cyanido ligands. The trans basal C—Tc—C angles are linear resulting in a square planar arrangement of the tetracyanido groups about the Tc center.

The Tc═O distance (1.7721 (12) Å) is virtually identical to the Re═O distance in K₃[ReO₂(CN)₄] [neutron study: 1.773 (8) Å (Fenn et al., 1971), X-ray study: 1.781 (3) Å (Murmann & Schlemper, 1971)]. An average Tc═O distance of 1.74 Å has been observed for an oxido ligand in cations of the type trans-[O₂R₄Tc]⁺ (R = 4-tert-butylpyridine, imidazole, 1-methylimidazole, trimethylenediamine) (Kastner et al., 1984; Fackler et al., 1985; Kremer et al., 1997) or trans-[O₂en₂Tc]⁺ (en = ethylenediamine) (Kastner et al., 1982) while a Tc—O distance of 2.559 (9) Å is observed in the [TcN(CN)₄(OH₂)]^2- dianion reported by Baldas et al. (1990).

The Tc—C distances (2.1423 (19) and 2.145 (2) Å) determined in this study are slightly longer than reported by Murmann & Schlemper (1971) and Fenn et al. (1971) for the [ReO₂(CN)₄]^3- anion (Re—C_ave = 2.13 Å). In addition, we see a deviation from linearity for one Tc—C—N angle (172.74 (15)° versus 177.71 (16)°). Similar bending is common in the [ReO₂(CN)₄]^3-, [ReO(OH)(CN)₄]^2- and [ReO(OH₂)(CN)₄]^- anions (ave. 175° versus 178°) (Fenn et al., 1971; Murmann & Schlemper, 1971; Purcell et al., 1989, 1990) and may be a result of inequivalent interactions with the surrounding environment.

(I) shows interionic interactions between the K⁺ cations and the [TcO₂(CN)₄]^3- anion. The K⁺ cations reside in two distinct environments [K1 located on a special position with inversion symmetry and K2 is located on a general position] (Fig 2). Each oxygen atom of the anion interacts with one K1 and two K2 atoms. The local environment about K1 is distorted octahedral, consisting of the following interactions: K1···O1 = 2.8235 (13) Å, K1···N1 = 2.8315 (18) Å, K1···N2 = 2.8598 (15) Å and the symmetry equivalents. On the other hand, the local environment about K2 is approximately tetrahedral with interactions of K2···O1 = 2.7936 (12) and 2.8262 (14) Å, K2···N1 = 2.8152 (16) Å and K2···N2 = 2.7877 (19) Å). In addition, there are three significantly longer contacts between K2 and N1 (3.1710 (16) and 3.5715 (16) Å) and K2 and N2 (3.1496 (17) Å).

Related literature top

The isotypic rhenate(V) analogue was reported by Fenn et al. (1971) (neutron study) and Murmann & Schlemper (1971) (X-ray study). For further information on dioxidotetracyanido anions of Tc and Re, see: Fackler et al. (1985); Kastner et al. (1982, 1984); Kremer et al. (1997). Luminescence properties of Tc complexes were reported by Del Negro et al. (2005, 2006). For further information on hydroxidooxidotetracyanido or aquaoxidotetracyanido anions of Tc and Re, see: Baldas et al. (1990); Purcell et al. (1989, 1990). For general reviews on technetium structures, see: Bandoli et al. (2001, 2006); Bartholoma et al. (2010); Tisato et al. (1994). Synthetic details are given by Trop et al. (1980). For a description of the Cambridge Structural Database, see: Allen (2002).

Experimental top

(I) is prepared from [TcO₂(py)₄]Cl (py = pyridyl) by the method of Trop et al. (1980). Complete cyanide substitution of the pyridyl groups of the starting material is achieved by adding an excess of alkaline cyanide.

In a typical preparation, 0.5 g of [TcO₂(py)₄]Cl was dissolved in a minimum amount of methanol. Addition of 50 ml of 1.2M KCN in 5:1 (v/v) methanol/water to the above resulted in an immediate green solution which turned yellow in approx. 5 minutes. This was followed by a gradual appearance of a fine yellow precipitate. The mixture was stirred on a hot plate set to low heat for an additional hour to ensure complete conversion. The supernatant was drawn off and the yellow precipitate was washed with diethyl ether. The yellow precipitate was dissolved in a minimal amount of water, followed by slow diffusion of methanol vapors, to yield crystals of (I) suitable for X-ray diffraction.

CAUTION! All syntheses and characterizations were performed with ⁹⁹Tc, which is a β-emitting isotope with a half-life of 2.13x10⁵ years. The handling of small quantities (generally <100 milligrams) of this material does not pose a serious health hazard since common laboratory materials provide adequate shielding. However, radiation safety procedures must be used to prevent contamination!

Structure description top

The isotypic rhenate(V) analogue was reported by Fenn et al. (1971) (neutron study) and Murmann & Schlemper (1971) (X-ray study). For further information on dioxidotetracyanido anions of Tc and Re, see: Fackler et al. (1985); Kastner et al. (1982, 1984); Kremer et al. (1997). Luminescence properties of Tc complexes were reported by Del Negro et al. (2005, 2006). For further information on hydroxidooxidotetracyanido or aquaoxidotetracyanido anions of Tc and Re, see: Baldas et al. (1990); Purcell et al. (1989, 1990). For general reviews on technetium structures, see: Bandoli et al. (2001, 2006); Bartholoma et al. (2010); Tisato et al. (1994). Synthetic details are given by Trop et al. (1980). For a description of the Cambridge Structural Database, see: Allen (2002).

Computing details top

Data collection: SMART (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2010); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. : The structural moieties of (I) with the atomic labelling scheme and 50% probability ellipsoids. [Symmetry code: (i) -x + 1, -y + 1, -z + 1].
	Fig. 2. : The extended packing motif of (I) in the bc plane showing the octahedral and tetrahedral environments about the K⁺ ions. Dashed lines indicate the K···O (red) and K···N (blue) interionic interactions [K1 in light pink, K2 in dark pink].

tripotassium trans-tetracyanidodioxidotechnetate(V) top

Crystal data top

K3[TcO₂(CN)₄]	Z = 1
M_r = 351.38	F(000) = 168
Triclinic, P1	D_x = 2.202 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.2539 (6) Å	Cell parameters from 3550 reflections
b = 6.9389 (6) Å	θ = 3.2–30.0°
c = 7.4347 (7) Å	µ = 2.51 mm⁻¹
α = 108.305 (1)°	T = 90 K
β = 109.816 (2)°	Fragment, yellow
γ = 104.143 (1)°	0.32 × 0.20 × 0.14 mm
V = 265.01 (4) Å³

Data collection top

Bruker SMART APEX diffractometer	1097 independent reflections
Radiation source: normal-focus sealed tube	1064 reflections with > σ(I)
Graphite monochromator	R_int = 0.072
ω scans	θ_max = 26.5°, θ_min = 3.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 2007)	h = −7→7
T_min = 0.490, T_max = 0.705	k = −8→8
3949 measured reflections	l = −9→9

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.020	w = 1/[σ²(F_o²) + (0.0114P)² + 0.0622P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.049	(Δ/σ)_max = 0.001
S = 1.09	Δρ_max = 0.77 e Å⁻³
1097 reflections	Δρ_min = −0.90 e Å⁻³
68 parameters	Extinction correction: SHELXTL (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.024 (3)

Crystal data top

K3[TcO₂(CN)₄]	γ = 104.143 (1)°
M_r = 351.38	V = 265.01 (4) Å³
Triclinic, P1	Z = 1
a = 6.2539 (6) Å	Mo Kα radiation
b = 6.9389 (6) Å	µ = 2.51 mm⁻¹
c = 7.4347 (7) Å	T = 90 K
α = 108.305 (1)°	0.32 × 0.20 × 0.14 mm
β = 109.816 (2)°

Data collection top

Bruker SMART APEX diffractometer	1097 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2007)	1064 reflections with > σ(I)
T_min = 0.490, T_max = 0.705	R_int = 0.072
3949 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.020	68 parameters
wR(F²) = 0.049	0 restraints
S = 1.09	Δρ_max = 0.77 e Å⁻³
1097 reflections	Δρ_min = −0.90 e Å⁻³

Special details top

Experimental. A suitable crystal was mounted on a glass fiber and immediately transferred to the goniostat bathed in a cold stream.

CAUTION!All syntheses and characterizations were performed with⁹⁹Tc, which is a β-emitting isotope with a half-life of 2.13x10⁵ years. The handling of small quantities (generally <100 milligrams) of this material does not pose a serious health hazard since common laboratory materials provide adequate shielding. However, radiation safety procedures must be used to prevent contamination.

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) top

	x	y	z	U_iso*/U_eq
K1	0.5000	0.0000	1.0000	0.01358 (15)
K2	0.04367 (6)	0.33536 (7)	0.69923 (6)	0.01283 (13)
Tc1	0.5000	0.5000	0.5000	0.00885 (11)
O1	0.6628 (2)	0.3641 (2)	0.39016 (18)	0.0123 (3)
N1	0.6522 (3)	0.3389 (3)	0.8804 (2)	0.0159 (4)
N2	−0.0098 (3)	0.0509 (3)	0.2506 (2)	0.0161 (4)
C1	0.5999 (3)	0.3996 (3)	0.7507 (3)	0.0120 (4)
C2	0.1707 (3)	0.2034 (3)	0.3254 (3)	0.0123 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
K1	0.0127 (3)	0.0130 (3)	0.0118 (3)	0.0033 (2)	0.0024 (2)	0.0064 (2)
K2	0.0118 (2)	0.0155 (3)	0.0129 (2)	0.00591 (17)	0.00588 (15)	0.00746 (18)
Tc1	0.00763 (14)	0.01073 (17)	0.00889 (14)	0.00383 (10)	0.00354 (9)	0.00513 (10)
O1	0.0110 (6)	0.0132 (7)	0.0131 (6)	0.0052 (5)	0.0050 (5)	0.0063 (5)
N1	0.0157 (7)	0.0175 (10)	0.0145 (7)	0.0059 (7)	0.0061 (6)	0.0084 (7)
N2	0.0139 (7)	0.0172 (9)	0.0164 (7)	0.0056 (7)	0.0055 (6)	0.0085 (7)
C1	0.0100 (8)	0.0120 (10)	0.0121 (8)	0.0033 (7)	0.0055 (6)	0.0035 (7)
C2	0.0136 (8)	0.0157 (11)	0.0106 (8)	0.0084 (8)	0.0055 (6)	0.0071 (7)

Geometric parameters (Å, º) top

Tc1—O1ⁱ	1.7721 (12)	N2—K2^v	2.7876 (19)
Tc1—O1	1.7721 (12)	N2—K1^vi	2.8598 (15)
Tc1—C1ⁱ	2.1423 (19)	K1—O1^vii	2.8235 (13)
Tc1—C1	2.1423 (19)	K1—O1^viii	2.8235 (13)
Tc1—C2	2.145 (2)	K1—N1	2.8315 (18)
Tc1—C2ⁱ	2.145 (2)	K1—N1^ix	2.8315 (18)
O1—K2ⁱⁱ	2.7937 (12)	K1—N2^x	2.8598 (15)
O1—K1ⁱⁱⁱ	2.8235 (13)	K1—N2^v	2.8598 (15)
O1—K2ⁱ	2.8262 (14)	K2—N2^v	2.7877 (19)
N1—C1	1.150 (3)	K2—O1^xi	2.7936 (12)
N1—K2^iv	2.8152 (16)	K2—N1^iv	2.8152 (16)
N1—K2ⁱⁱ	3.1710 (16)	K2—O1ⁱ	2.8262 (14)
N2—C2	1.151 (3)	K2—N1^xi	3.1710 (16)

O1ⁱ—Tc1—O1	180.0	C2—N2—K2^v	124.85 (13)
O1ⁱ—Tc1—C1ⁱ	90.13 (6)	C2—N2—K1^vi	127.59 (15)
O1—Tc1—C1ⁱ	89.87 (6)	K2^v—N2—K1^vi	107.51 (6)
O1ⁱ—Tc1—C1	89.87 (6)	O1^vii—K1—O1^viii	180.00 (5)
O1—Tc1—C1	90.13 (6)	O1^vii—K1—N1	97.86 (4)
C1ⁱ—Tc1—C1	179.999 (1)	O1^viii—K1—N1	82.14 (4)
O1ⁱ—Tc1—C2	88.60 (6)	O1^vii—K1—N1^ix	82.14 (4)
O1—Tc1—C2	91.40 (6)	O1^viii—K1—N1^ix	97.86 (4)
C1ⁱ—Tc1—C2	92.34 (7)	N1—K1—N1^ix	180.00 (7)
C1—Tc1—C2	87.66 (7)	O1^vii—K1—N2^x	104.18 (4)
O1ⁱ—Tc1—C2ⁱ	91.40 (6)	O1^viii—K1—N2^x	75.82 (4)
O1—Tc1—C2ⁱ	88.60 (6)	N1—K1—N2^x	95.00 (5)
C1ⁱ—Tc1—C2ⁱ	87.66 (7)	N1^ix—K1—N2^x	85.00 (5)
C1—Tc1—C2ⁱ	92.34 (7)	O1^vii—K1—N2^v	75.82 (4)
C2—Tc1—C2ⁱ	180.0	O1^viii—K1—N2^v	104.18 (4)
Tc1—O1—K2ⁱⁱ	111.70 (5)	N1—K1—N2^v	85.00 (5)
Tc1—O1—K1ⁱⁱⁱ	131.58 (5)	N1^ix—K1—N2^v	95.00 (5)
K2ⁱⁱ—O1—K1ⁱⁱⁱ	107.62 (4)	N2^x—K1—N2^v	180.0
Tc1—O1—K2ⁱ	106.54 (6)	N2^v—K2—O1^xi	123.16 (4)
K2ⁱⁱ—O1—K2ⁱ	98.26 (4)	N2^v—K2—N1^iv	101.64 (5)
K1ⁱⁱⁱ—O1—K2ⁱ	94.38 (4)	O1^xi—K2—N1^iv	125.77 (5)
N1—C1—Tc1	177.71 (16)	N2^v—K2—O1ⁱ	139.59 (4)
N2—C2—Tc1	172.74 (15)	O1^xi—K2—O1ⁱ	81.74 (4)
C1—N1—K2^iv	116.78 (14)	N1^iv—K2—O1ⁱ	82.38 (5)
C1—N1—K1	145.03 (14)	N2^v—K2—N1^xi	84.21 (5)
K2^iv—N1—K1	94.44 (5)	O1^xi—K2—N1^xi	77.02 (4)
C1—N1—K2ⁱⁱ	73.15 (11)	N1^iv—K2—N1^xi	79.06 (5)
K2^iv—N1—K2ⁱⁱ	100.94 (5)	O1ⁱ—K2—N1^xi	135.31 (4)
K1—N1—K2ⁱⁱ	118.11 (6)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x+1, y, z; (iii) x, y, z−1; (iv) −x+1, −y+1, −z+2; (v) −x, −y, −z+1; (vi) x−1, y, z−1; (vii) −x+1, −y, −z+1; (viii) x, y, z+1; (ix) −x+1, −y, −z+2; (x) x+1, y, z+1; (xi) x−1, y, z.

Experimental details

Crystal data
Chemical formula	K3[TcO₂(CN)₄]
M_r	351.38
Crystal system, space group	Triclinic, P1
Temperature (K)	90
a, b, c (Å)	6.2539 (6), 6.9389 (6), 7.4347 (7)
α, β, γ (°)	108.305 (1), 109.816 (2), 104.143 (1)
V (Å³)	265.01 (4)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	2.51
Crystal size (mm)	0.32 × 0.20 × 0.14

Data collection
Diffractometer	Bruker SMART APEX
Absorption correction	Multi-scan (SADABS; Sheldrick, 2007)
T_min, T_max	0.490, 0.705
No. of measured, independent and observed [ > σ(I)] reflections	3949, 1097, 1064
R_int	0.072
(sin θ/λ)_max (Å⁻¹)	0.627

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.020, 0.049, 1.09
No. of reflections	1097
No. of parameters	68
Δρ_max, Δρ_min (e Å⁻³)	0.77, −0.90

Computer programs: SMART (Bruker, 2006), SAINT (Bruker, 2006), SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2010).

Selected geometric parameters (Å, º) top

Tc1—O1	1.7721 (12)	N1—C1	1.150 (3)
Tc1—C1	2.1423 (19)	N2—C2	1.151 (3)
Tc1—C2	2.145 (2)

N1—C1—Tc1	177.71 (16)	N2—C2—Tc1	172.74 (15)

Acknowledgements

We thank Dr Sean E. Hightower and Mr Chuck Z. Soderquist for helpful discussion during the synthesis and crystallization. Financial support was provided by DOE EMSP grant DE–FG02-07ER51629. The SMART APEX Diffraction Facility (University of Idaho) was funded by NSF-EPSCoR and the M. J. Murdock Charitable Trust, Vancouver, WA. The Radiochemical Processing and the Environmental Molecular Science Laboratories are national scientific user facilities sponsored by the DOE Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for the DOE under Contract DE–AC05-76RL01830.

References

Allen, F. H. (2002). Acta Cryst. B58, 380–388. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Baldas, J., Boas, J. F., Colmanet, S. F. & Mackay, J. F. (1990). Inorg. Chim. Acta, 170, 233–239. CSD CrossRef CAS Web of Science Google Scholar
Bandoli, G., Dolmella, A., Porchia, M., Refosco, F. & Tisato, F. (2001). Coord. Chem. Rev. 214, 43–90. Web of Science CrossRef CAS Google Scholar
Bandoli, G., Tisato, F., Dolmella, A. & Agostini, S. (2006). Coord. Chem. Rev. 250, 561–573. Web of Science CrossRef CAS Google Scholar
Bartholoma, M. D., Louie, A. S., Valliant, J. F. & Zubieta, J. (2010). Chem. Rev. 110, 2903–2920. Web of Science CrossRef CAS PubMed Google Scholar
Brandenburg, K. (2010). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2006). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Del Negro, A. S., Seliskar, C. J., Heineman, W. R., Hightower, S. E., Bryan, S. A. & Sullivan, B. P. (2006). J. Am. Chem. Soc. 128, 16494–16495. Web of Science CrossRef PubMed CAS Google Scholar
Del Negro, A. S., Wang, Z., Seliskar, C. J., Heineman, W. R., Hightower, S. E., Bryan, S. A. & Sullivan, B. P. (2005). J. Am. Chem. Soc. 127, 14978–14979. Web of Science CrossRef PubMed CAS Google Scholar
Fackler, P. H., Lindsay, M. J., Clarke, M. J. & Kastner, M. E. (1985). Inorg. Chim. Acta, 109, 39–49. CSD CrossRef CAS Web of Science Google Scholar
Fenn, R. H., Graham, A. J. & Johnson, N. P. (1971). J. Chem. Soc. A, pp. 2880–2883. CrossRef Google Scholar
Kastner, M. E., Fackler, P. H., Clarke, M. J. & Deutsch, E. (1984). Inorg. Chem. 23, 4683–4688. CSD CrossRef CAS Web of Science Google Scholar
Kastner, M. E., Lindsay, M. J. & Clarke, M. J. (1982). Inorg. Chem. 21, 2037–2040. CSD CrossRef CAS Web of Science Google Scholar
Kremer, C., Gancheff, J., Kremer E., Mombru, A. W., Gonzalez, O., Mariezcurrena, R., Suescun, L, Cubas, M. L. & Ventura, O. N. (1997). Polyhedron, 19, 3311–3316. Google Scholar
Murmann, R. K. & Schlemper, E. O. (1971). Inorg. Chem. 10, 2352–2354. CrossRef CAS Web of Science Google Scholar
Purcell, W., Roodt, A., Basson, S. S. & Leipoldt, J. G. (1989). Transition Met. Chem. 14, 5–6. CSD CrossRef CAS Web of Science Google Scholar
Purcell, W., Roodt, A., Basson, S. S. & Leipoldt, J. G. (1990). Transition Met. Chem. 15, 239–241. CSD CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (2007). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Tisato, F., Refosco, F. & Bandoli, G. (1994). Coord. Chem. Rev. 135–136, 325-397. CrossRef Web of Science Google Scholar
Trop, H. S., Jones, A. G. & Davison, A. (1980). Inorg. Chem. 19, 1993–1997. CrossRef CAS Web of Science Google Scholar