Analysis of charge density in nona­aqua­gadolinium(III) trifluoromethanesulfonate – insight into Gd^III—OH₂ bonding

The experimental charge-density distribution in [Gd(H₂O)₉](CF₃SO₃)₃ has been analysed and compared with the theoretical density functional theory calculations. Although the Gd—OH₂ bonds are mainly ionic, a covalent contribution is detectable when inspecting both the topological parameters of these bonds and the natural bond orbital results. This contribution originates from small electron transfer from the lone pairs of oxygen atoms to empty 5d and 6s spin orbitals of Gd³⁺.

Computing details

Data collection: CrysAlis PRO 1.171.38.46 (Rigaku OD, 2015); cell refinement: CrysAlis PRO 1.171.38.46 (Rigaku OD, 2015); data reduction: CrysAlis PRO 1.171.38.46 (Rigaku OD, 2015); program(s) used to refine structure: Volkov et al., (2006); molecular graphics: Volkov et al., (2006); software used to prepare material for publication: Volkov et al., (2006).

(I)

Crystal data

C3H18F9GdO18S3	Mo Kα radiation, λ = 0.71073 Å
Mr = 766.60	Cell parameters from 61419 reflections
Hexagonal, P63/m	θ = 2.8–69.8°
a = 13.7828 (9) Å	µ = 3.14 mm^−1
c = 7.3148 (5) Å	T = 80 K
V = 1203.39 (14) Å^3	Irregular, colourless
Z = 2	0.42 × 0.36 × 0.29 mm
F(000) = 746

Data collection

Xcalibur, Ruby diffractometer	86103 measured reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	8039 independent reflections
Graphite monochromator	Rint = 0.021
Detector resolution: 10.3456 pixels mm^-1	θmax = 69.8°, θmin = 1.7°
ω scans	h = −35→29
Absorption correction: analytical CrysAlisPro 1.171.38.46 (Rigaku Oxford Diffraction, 2015) Analytical numeric absorption correction using a multifaceted crystal model based on expressions derived by R.C. Clark & J.S. Reid. (Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	k = −36→36
Tmin = 0.401, Tmax = 0.542	l = −14→19

Refinement

Refinement on F^2	1 restraint
Least-squares matrix: full	w2 = q/[s^2(Fo^2) + (0.00 P)^2 + 0.20 P + 0.00 + 0.00 sin(th)] where P = (0.3333 Fo^2 + 0.6667 Fc^2) q = 1.0
R[F^2 > 2σ(F^2)] = 0.009	(Δ/σ)max = 0.0004
wR(F^2) = 0.023	Δρmax = 0.68 e Å^−3
S = 1.84	Δρmin = −0.73 e Å^−3
5325 reflections	Extinction correction: Becker-Coppens type 1 Lorentzian isotropic, Becker, P.J. & Coppens, P. (1974) Acta Cryst., A30, 129-153.
203 parameters	Extinction coefficient: 0.441 (4)

Special details

Refinement. Refinement of F² against reflections with F^2>3sigma(F2).

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

	x	y	z	Uiso*/Ueq
Gd	0.333333	0.666667	0.25	0.006
S	0.320081 (3)	0.379073 (3)	0.75	0.009
F(1)	0.15829 (3)	0.19800 (3)	0.60177 (7)	0.029
F(2)	0.28008 (4)	0.17355 (3)	0.75	0.023
O(W1)	0.209383 (7)	0.546060 (8)	0.485602 (12)	0.012
O(W2)	0.143743 (11)	0.652439 (13)	0.25	0.013
O(3)	0.383736 (9)	0.398876 (10)	0.917112 (13)	0.014
O(4)	0.247480 (12)	0.427253 (12)	0.75	0.013
C	0.222479 (15)	0.227605 (14)	0.75	0.016
H(11)	0.128583	0.498817	0.457902	0.0360 (19)*
H(12)	0.232552	0.509706	0.579031	0.0184 (13)*
H(21)	0.095802	0.648151	0.354029	0.0302 (14)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Gd	0.006605 (5)	0.006605 (5)	0.005956 (6)	0.003308 (3)	0	0
S	0.011386 (11)	0.011301 (11)	0.007684 (10)	0.007767 (9)	0	0
F(1)	0.02660 (10)	0.02233 (9)	0.03731 (13)	0.01106 (8)	−0.01592 (10)	−0.01108 (9)
F(2)	0.02681 (12)	0.01614 (9)	0.03071 (13)	0.01482 (9)	0	0
O(W1)	0.00974 (2)	0.01254 (2)	0.01141 (2)	0.004927 (19)	0.000690 (18)	0.003402 (19)
O(W2)	0.01188 (3)	0.01802 (4)	0.01023 (3)	0.00941 (3)	0	0
O(3)	0.01731 (3)	0.02011 (3)	0.01077 (2)	0.01298 (3)	−0.00410 (2)	−0.00320 (2)
O(4)	0.01688 (4)	0.01728 (4)	0.01149 (3)	0.01342 (4)	0	0
C	0.01587 (5)	0.01293 (4)	0.02025 (6)	0.00762 (4)	0	0

Geometric parameters (Å, º)

GD—O(W1)	2.4108 (3)	F(1)—F(1)^i	2.9103 (14)
GD—O(W2)	2.5208 (4)	F(1)—F(2)^i	3.0359 (16)
S—O(3)	1.4488 (3)	F(1)—C	1.3281 (11)
S—O(4)	1.4515 (4)	F(2)—C	1.3331 (12)
S—C	1.8329 (6)
O(W1)—GD—O(W1)^ii	74.542 (11)	O(3)—S—C	104.183 (19)
O(W1)—GD—O(W1)^iii	91.263 (15)	O(4)—S—C	103.88 (3)
O(W1)—GD—O(W1)^iv	139.070 (6)	S—C—F(1)	110.29 (7)
O(W1)—GD—O(W2)	66.217 (10)	S—C—F(2)	109.49 (7)
O(W1)—GD—O(W2)^ii	72.957 (11)	H(11)—O(W1)—H(12)	110.48 (3)
O(W1)—GD—O(W2)^v	134.137 (8)	H(21)—O(W2)—H(21)^iii	100.46 (4)
O(W2)—GD—O(W2)^ii	120.0	F(1)—C—F(1)^vi	109.45 (17)
O(3)—S—O(3)^vi	115.07 (3)	F(1)—C—F(2)	108.64 (7)
O(3)—S—O(4)	113.883 (16)

Symmetry codes: (i) x−y, x, −z+1; (ii) −y+1, x−y+1, z; (iii) x, y, −z+1/2; (iv) −y+1, x−y+1, −z+1/2; (v) −x+y, −x+1, z; (vi) x, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O(W1)—H(11)···O(3)^vii	0.99	1.84	2.8123 (4)	166
O(W1)—H(12)···O(4)	0.99	1.77	2.7491 (4)	170
O(W2)—H(21)···O(3)^viii	0.99	1.93	2.9045 (4)	166

Symmetry codes: (vii) x−y, x, z−1/2; (viii) −x+y, −x+1, −z+3/2.