Poly­sulfonyl­amines. CLXXI. [Di­(methane­sulfonyl)­amido-[kappa]N]­bis(2-picoline-[kappa]N)copper(I)

The title compound, [Cu(C₂H₆NO₄S₂)(C₆H₇N)₂], consists of monomeric mol­ecules in which the Cu atom displays planar but irregular coordination by three N-atom donors; Cu-N = 2.1054 (12) (amide N), 1.9514 (12) and 1.9589 (12) Å, and N-Cu-N = 141.24 (5), 111.54 (5) and 107.20 (5)°. Intramolecular Cu...O contacts are observed. The packing involves (interconnected) layer formation via C-H...O interactions in two directions, three hydrogen bonds combining to form layers parallel to (101) and five to form layers parallel to (10).

S1. Comment

We are interested in the synthesis and structure of complexes of the coinage metals with N ligands. We have been able to show that amine complexes of gold(I) are much more stable than normally assumed on the basis of hard/soft incompatibility, and that they can be stabilized further by using disulfonylamides (RSO₂)₂N⁻, especially di(methanesulfonyl)amide (R = CH₃; henceforth DMS), as counterions (Ahrens et al., 2000, and references therein). Amine complexes of silver(I) disulfonylamides are easier to prepare (Zerbe & Jones, 2004) because the silver salts are available as stable starting materials, whereas homoleptic gold(I) disulfonylamides are not known. The disulfonylamides can coordinate to silver(I), but rarely to gold(I), which has little tendency to increase its coordination number beyond two.

We now wished to extend our studies to complexes of copper(I). The starting material, copper(I) DMS, is available (Linoh, 1989) but is of limited stability. Nevertheless, an initial synthesis and structure, that of the title compound, (I) (2-picoline is 2-methylpyridine), proved successful. The molecule of (I) is shown in Fig. 1. \sch

The Cu centre of (I) exhibits planar three-coordination by two picoline N atoms and the N atom of the amide (r.m.s. deviation of four atoms 0.007 Å), but the coordination is far from regular, with the Cu—N_amide bond being 0.15 Å longer than the Cu—N_picoline bond. Consistent with this, the angle opposite Cu—N_amide is (by far) the largest (Table 1).

The dimensions of the picoline ligands may be regarded as normal. The ring angles at N are slightly less than the ideal 120° (Table 1).

All three ligands are essentially perpendicular to the CuN₃ plane, with interplanar angles of 85.37 (5)° from the first picoline, 78.34 (5)° from the second and 80.34 (3)° from the SNS plane of the amide.

A search of the Cambridge Structural Database (Version 5.25; Allen, 2002) showed that there are few examples of monomeric copper(I) complexes with three monodentate N ligands. Habiyakare et al. (1992) presented the structures of seven [CuL₃]⁺ complexes (L are various methylpyridines). In each case, the coordination geometry was planar but with considerable variation in angles, from almost regular (all three angles 120°) to irregular (106–141°). Particularly wide angles tended to be associated with ligands that were approximately coplanar with the CuN₃ plane, and with weak axial contacts from the Cu centres to the counteranions. The Cu—N bond lengths clustered around 2.00 Å, but with a range of 1.962 (4)–2.10 (1) Å; the C—N—C angles showed a slight tendency to be less than 120°, with an average value of 118.6°, but again with appreciable scatter (115.9–124.9°). Näther & Beck (2004) have recently presented the structure of the neutral molecule chlorobis(piperidine)copper(I), which is also trigonal planar at Cu, with a wide N—Cu—N angle of 135.37 (7)°.

The DMS group in (I) displays the usual conformation, with approximate C₂ symmetry, whereby the local twofold axis is the bisector of the S—N—S angle. As a measure of the deviation from ideal symmetry, we use the average absolute difference Δτ_SN between equivalent torsion angles about the S—N bonds; here, the value is 3.8°. A further general feature is the presence of two antiperiplanar S—N—S—O_ap groupings that together form a W-shaped sequence of five atoms. The two O_ap atoms, which as usual form the narrower O—S—N angles (as in the essentially `free' DMS anion in its 1-aza-4-azoniabicyclo[2.2.2]octane salt; Henschel et al., 1997), are involved in short intramolecular contacts to the copper atom, with Cu···O1 3.0545 (12) and Cu···O3 3.0360 (11) Å.

In a long series of publications, we have established that the O atoms of the DMS group are versatile hydrogen-bond acceptors (e.g. Wijaya et al., 2004, and references therein). However, the current structure contains no classical hydrogen-bond donors. In such cases, `weak' hydrogen bonds of the form C—H···O (Desiraju & Steiner, 1999) would be expected, and are indeed observed (Table 2). In the following discussion, the numbering refers to the order in Table 2.

The complete hydrogen-bonding pattern in (I) is three-dimensional and complex, but may be analysed in terms of layer formation in two directions. Hydrogen bonds 1–3, including one from each para H atom of the picoline ligands, combine to form layers parallel to (101) (Fig. 2). The remaining hydrogen bonds 4–8, of which 4 and 5 form a bifurcated (C—H···)₂O unit, and 7 and 8 represent hydrogen bonds between DMS units (as we have commonly observed, e.g. Wijaya et al., 2004), combine to form layers parallel to (102) (Fig. 3). The final interaction in Table 2 is included as a reminder that metal atoms may also fulfil the criteria for hydrogen-bond acceptors.

S2. Experimental

Copper(I) di(methanesulfonyl)amide was prepared by the method of Linoh (1989), dissolved in excess 2-picoline and the solution overlayered with diethyl ether. Despite considerable decomposition, a few colourless crystals of (I) formed. Clearly, the method needs thorough optimization before it can be used as a reliable synthetic procedure.

S3. Refinement

Methyl H atoms were clearly identified in difference syntheses, idealized and refined as rigid groups allowed to rotate but not tip. Other H atoms were included using a riding model. C—H bond lengths were fixed at 0.98 (methyl) or 0.95 Å (aromatic), and methyl H—C—H angles at 109.5°. U_iso(H) values were fixed at 1.2U(eq) of the parent atom.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecule of (I) in the crystal, with the atom-numbering scheme. Displacement ellipsoids are drawn at 30% probability levels and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. The layer formation in (I), viewed perpendicular to (101). Hydrogen bonds are indicated by dashed lines. H atoms not involved in hydrogen bonds have been omitted.
	Fig. 3. The layer formation in (I), viewed perpendicular to (102). Hydrogen bonds are indicated by dashed lines. H atoms not involved in hydrogen bonds have been omitted.

[Bis(methylsulfonyl)amido-κN]bis(2-picoline-κN)copper(I)

Crystal data

[Cu(C2H6NO4S2)(C6H7N)2]	F(000) = 872
Mr = 421.99	Dx = 1.570 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 7138 reflections
a = 10.2353 (6) Å	θ = 2–30.5°
b = 7.7684 (4) Å	µ = 1.48 mm^−1
c = 23.0287 (14) Å	T = 133 K
β = 102.780 (4)°	Block, colourless
V = 1785.69 (18) Å^3	0.39 × 0.25 × 0.17 mm
Z = 4

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	5215 independent reflections
Radiation source: fine-focus sealed tube	4267 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.030
Detector resolution: 8.192 pixels mm^-1	θmax = 30.0°, θmin = 1.8°
ω and ϕ scans	h = −14→14
Absorption correction: multi-scan (SADABS; Bruker, 1998)	k = −10→10
Tmin = 0.625, Tmax = 0.746	l = −31→32
35736 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.026	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.073	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0432P)^2] where P = (Fo^2 + 2Fc^2)/3
5215 reflections	(Δ/σ)max = 0.002
221 parameters	Δρmax = 0.43 e Å^−3
0 restraints	Δρmin = −0.33 e Å^−3

Special details

Experimental. {Di(methanesulfonyl)amido-N}bis(2-picolino)copper(I)

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.70655 (15)	0.1471 (2)	0.51204 (6)	0.0249 (3)
H1A	0.7838	0.0691	0.5196	0.030*
H1B	0.7365	0.2641	0.5058	0.030*
H1C	0.6416	0.1090	0.4764	0.030*
C2	0.80651 (15)	−0.0639 (2)	0.70031 (7)	0.0263 (3)
H2A	0.8825	−0.1232	0.7259	0.032*
H2B	0.7574	−0.1447	0.6707	0.032*
H2C	0.7467	−0.0198	0.7247	0.032*
N1	0.73750 (10)	0.21799 (16)	0.63011 (5)	0.0186 (2)
O1	0.52550 (10)	0.27237 (16)	0.56227 (4)	0.0307 (3)
O2	0.59185 (11)	−0.02973 (15)	0.58231 (5)	0.0305 (3)
O3	0.93869 (10)	0.22316 (14)	0.70889 (4)	0.0274 (2)
O4	0.93988 (10)	0.03526 (15)	0.62317 (5)	0.0276 (2)
S1	0.63064 (3)	0.14510 (5)	0.573639 (15)	0.01933 (8)
S2	0.86576 (3)	0.10869 (5)	0.663756 (15)	0.01823 (8)
Cu	0.747080 (16)	0.48750 (2)	0.639749 (7)	0.01940 (6)
N11	0.82445 (11)	0.59523 (16)	0.57854 (5)	0.0194 (2)
C12	0.95650 (14)	0.63068 (19)	0.58710 (6)	0.0210 (3)
C13	1.00977 (15)	0.7048 (2)	0.54267 (7)	0.0263 (3)
H13	1.1028	0.7298	0.5500	0.032*
C14	0.92847 (16)	0.7424 (2)	0.48787 (7)	0.0290 (3)
H14	0.9644	0.7924	0.4571	0.035*
C15	0.79310 (16)	0.7052 (2)	0.47895 (7)	0.0289 (3)
H15	0.7342	0.7283	0.4417	0.035*
C16	0.74509 (14)	0.6341 (2)	0.52514 (7)	0.0248 (3)
H16	0.6518	0.6116	0.5190	0.030*
C17	1.04282 (15)	0.5863 (2)	0.64671 (7)	0.0296 (3)
H17A	1.0047	0.6373	0.6782	0.036*
H17B	1.1333	0.6316	0.6494	0.036*
H17C	1.0469	0.4609	0.6515	0.036*
N21	0.67708 (12)	0.54473 (16)	0.70996 (5)	0.0202 (2)
C22	0.55320 (14)	0.61205 (19)	0.70606 (7)	0.0248 (3)
C23	0.51098 (17)	0.6591 (2)	0.75719 (8)	0.0343 (4)
H23	0.4240	0.7062	0.7540	0.041*
C24	0.59436 (18)	0.6381 (3)	0.81256 (8)	0.0404 (4)
H24	0.5656	0.6701	0.8475	0.049*
C25	0.72076 (17)	0.5693 (3)	0.81626 (7)	0.0357 (4)
H25	0.7807	0.5537	0.8538	0.043*
C26	0.75772 (15)	0.5239 (2)	0.76394 (7)	0.0254 (3)
H26	0.8441	0.4758	0.7664	0.031*
C27	0.46708 (16)	0.6334 (2)	0.64483 (8)	0.0335 (4)
H27A	0.5118	0.7101	0.6215	0.040*
H27B	0.3807	0.6833	0.6476	0.040*
H27C	0.4523	0.5209	0.6252	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0248 (7)	0.0317 (9)	0.0190 (7)	−0.0039 (6)	0.0066 (5)	−0.0020 (6)
C2	0.0267 (7)	0.0225 (8)	0.0278 (8)	−0.0019 (6)	0.0019 (6)	0.0079 (6)
N1	0.0188 (6)	0.0169 (6)	0.0179 (5)	0.0011 (4)	−0.0008 (4)	−0.0004 (4)
O1	0.0212 (5)	0.0453 (7)	0.0241 (5)	0.0103 (5)	0.0018 (4)	0.0048 (5)
O2	0.0307 (6)	0.0322 (7)	0.0258 (6)	−0.0157 (5)	0.0002 (5)	0.0012 (4)
O3	0.0276 (5)	0.0235 (6)	0.0253 (5)	−0.0037 (4)	−0.0065 (4)	−0.0026 (4)
O4	0.0228 (5)	0.0318 (6)	0.0288 (6)	0.0064 (4)	0.0066 (4)	−0.0008 (5)
S1	0.01599 (15)	0.0243 (2)	0.01710 (16)	−0.00216 (12)	0.00241 (12)	0.00144 (12)
S2	0.01779 (15)	0.01625 (17)	0.01905 (16)	−0.00044 (12)	0.00064 (12)	−0.00038 (12)
Cu	0.01858 (9)	0.02048 (11)	0.02020 (10)	−0.00104 (6)	0.00658 (7)	0.00125 (6)
N11	0.0197 (5)	0.0173 (6)	0.0220 (6)	0.0006 (4)	0.0061 (4)	0.0008 (4)
C12	0.0211 (6)	0.0211 (8)	0.0218 (7)	−0.0009 (5)	0.0072 (5)	−0.0012 (5)
C13	0.0228 (7)	0.0326 (9)	0.0260 (7)	−0.0037 (6)	0.0105 (6)	0.0004 (6)
C14	0.0334 (8)	0.0309 (9)	0.0265 (7)	0.0002 (7)	0.0148 (6)	0.0060 (6)
C15	0.0323 (8)	0.0317 (9)	0.0225 (7)	0.0047 (7)	0.0056 (6)	0.0078 (6)
C16	0.0214 (7)	0.0254 (8)	0.0270 (7)	0.0020 (6)	0.0039 (6)	0.0048 (6)
C17	0.0228 (7)	0.0413 (10)	0.0240 (8)	−0.0052 (7)	0.0036 (6)	0.0033 (7)
N21	0.0216 (6)	0.0161 (6)	0.0248 (6)	−0.0033 (4)	0.0094 (5)	−0.0014 (5)
C22	0.0233 (7)	0.0175 (8)	0.0363 (8)	−0.0037 (5)	0.0127 (6)	−0.0009 (6)
C23	0.0283 (8)	0.0295 (9)	0.0515 (11)	−0.0035 (6)	0.0224 (8)	−0.0091 (8)
C24	0.0433 (10)	0.0473 (12)	0.0382 (10)	−0.0114 (8)	0.0250 (8)	−0.0165 (8)
C25	0.0380 (9)	0.0453 (11)	0.0256 (8)	−0.0095 (8)	0.0107 (7)	−0.0087 (7)
C26	0.0235 (7)	0.0269 (9)	0.0269 (8)	−0.0046 (6)	0.0079 (6)	−0.0027 (6)
C27	0.0241 (7)	0.0329 (10)	0.0437 (10)	0.0022 (7)	0.0077 (7)	0.0069 (7)

Geometric parameters (Å, º)

C1—S1	1.7618 (14)	C14—C15	1.385 (2)
C1—H1A	0.9800	C14—H14	0.9500
C1—H1B	0.9800	C15—C16	1.382 (2)
C1—H1C	0.9800	C15—H15	0.9500
C2—S2	1.7606 (15)	C16—H16	0.9500
C2—H2A	0.9800	C17—H17A	0.9800
C2—H2B	0.9800	C17—H17B	0.9800
C2—H2C	0.9800	C17—H17C	0.9800
N1—S1	1.6059 (11)	N21—C26	1.3412 (19)
N1—S2	1.6107 (11)	N21—C22	1.3561 (18)
O1—S1	1.4421 (11)	C22—C23	1.390 (2)
O2—S1	1.4412 (11)	C22—C27	1.498 (2)
O3—S2	1.4440 (10)	C23—C24	1.378 (3)
O4—S2	1.4451 (11)	C23—H23	0.9500
Cu—N1	2.1054 (12)	C24—C25	1.385 (2)
Cu—N11	1.9514 (12)	C24—H24	0.9500
Cu—N21	1.9589 (12)	C25—C26	1.386 (2)
N11—C16	1.3497 (18)	C25—H25	0.9500
N11—C12	1.3504 (17)	C26—H26	0.9500
C12—C13	1.386 (2)	C27—H27A	0.9800
C12—C17	1.499 (2)	C27—H27B	0.9800
C13—C14	1.381 (2)	C27—H27C	0.9800
C13—H13	0.9500
N11—Cu—N21	141.24 (5)	C13—C14—C15	118.18 (14)
N11—Cu—N1	111.54 (5)	C13—C14—H14	120.9
N21—Cu—N1	107.20 (5)	C15—C14—H14	120.9
S1—C1—H1A	109.5	C16—C15—C14	118.91 (14)
S1—C1—H1B	109.5	C16—C15—H15	120.5
H1A—C1—H1B	109.5	C14—C15—H15	120.5
S1—C1—H1C	109.5	N11—C16—C15	123.10 (14)
H1A—C1—H1C	109.5	N11—C16—H16	118.4
H1B—C1—H1C	109.5	C15—C16—H16	118.4
S2—C2—H2A	109.5	C12—C17—H17A	109.5
S2—C2—H2B	109.5	C12—C17—H17B	109.5
H2A—C2—H2B	109.5	H17A—C17—H17B	109.5
S2—C2—H2C	109.5	C12—C17—H17C	109.5
H2A—C2—H2C	109.5	H17A—C17—H17C	109.5
H2B—C2—H2C	109.5	H17B—C17—H17C	109.5
S1—N1—S2	122.70 (8)	C26—N21—C22	118.86 (13)
S1—N1—Cu	116.32 (6)	C26—N21—Cu	118.37 (10)
S2—N1—Cu	117.36 (6)	C22—N21—Cu	122.70 (10)
O2—S1—O1	116.99 (7)	N21—C22—C23	120.45 (15)
O1—S1—N1	104.63 (7)	N21—C22—C27	116.87 (14)
O3—S2—N1	104.96 (6)	C23—C22—C27	122.68 (14)
O2—S1—N1	112.29 (6)	C24—C23—C22	120.50 (15)
O4—S2—N1	112.68 (6)	C24—C23—H23	119.7
O2—S1—C1	107.68 (7)	C22—C23—H23	119.7
O1—S1—C1	106.99 (7)	C23—C24—C25	118.79 (15)
N1—S1—C1	107.84 (6)	C23—C24—H24	120.6
O3—S2—O4	116.54 (7)	C25—C24—H24	120.6
O3—S2—C2	107.62 (7)	C24—C25—C26	118.40 (16)
O4—S2—C2	107.12 (8)	C24—C25—H25	120.8
N1—S2—C2	107.53 (7)	C26—C25—H25	120.8
C16—N11—C12	117.93 (12)	N21—C26—C25	123.00 (15)
C16—N11—Cu	119.71 (9)	N21—C26—H26	118.5
C12—N11—Cu	122.35 (10)	C25—C26—H26	118.5
N11—C12—C13	121.42 (13)	C22—C27—H27A	109.5
N11—C12—C17	117.05 (12)	C22—C27—H27B	109.5
C13—C12—C17	121.53 (13)	H27A—C27—H27B	109.5
C14—C13—C12	120.43 (14)	C22—C27—H27C	109.5
C14—C13—H13	119.8	H27A—C27—H27C	109.5
C12—C13—H13	119.8	H27B—C27—H27C	109.5
S2—N1—S1—O2	45.26 (11)	Cu—N11—C12—C17	−1.01 (19)
Cu—N1—S1—O2	−156.78 (7)	N11—C12—C13—C14	−0.8 (2)
S2—N1—S1—O1	173.13 (8)	C17—C12—C13—C14	179.14 (15)
Cu—N1—S1—O1	−28.91 (8)	C12—C13—C14—C15	0.5 (2)
S2—N1—S1—C1	−73.22 (10)	C13—C14—C15—C16	0.6 (2)
Cu—N1—S1—C1	84.75 (8)	C12—N11—C16—C15	1.2 (2)
S1—N1—S2—O3	176.71 (8)	Cu—N11—C16—C15	−177.81 (13)
Cu—N1—S2—O3	18.96 (8)	C14—C15—C16—N11	−1.5 (3)
S1—N1—S2—O4	48.91 (11)	N11—Cu—N21—C26	−98.97 (13)
Cu—N1—S2—O4	−108.84 (8)	N1—Cu—N21—C26	79.16 (11)
S1—N1—S2—C2	−68.90 (10)	N11—Cu—N21—C22	77.78 (14)
Cu—N1—S2—C2	133.35 (8)	N1—Cu—N21—C22	−104.09 (12)
S1—N1—Cu—N11	−70.08 (8)	C26—N21—C22—C23	0.2 (2)
S2—N1—Cu—N11	89.10 (7)	Cu—N21—C22—C23	−176.49 (11)
S1—N1—Cu—N21	111.18 (7)	C26—N21—C22—C27	179.78 (14)
S2—N1—Cu—N21	−89.64 (7)	Cu—N21—C22—C27	3.05 (19)
N21—Cu—N11—C16	−96.18 (13)	N21—C22—C23—C24	0.0 (2)
N1—Cu—N11—C16	85.74 (12)	C27—C22—C23—C24	−179.52 (16)
N21—Cu—N11—C12	84.91 (13)	C22—C23—C24—C25	0.0 (3)
N1—Cu—N11—C12	−93.17 (12)	C23—C24—C25—C26	−0.3 (3)
C16—N11—C12—C13	0.0 (2)	C22—N21—C26—C25	−0.5 (2)
Cu—N11—C12—C13	178.95 (11)	Cu—N21—C26—C25	176.36 (13)
C16—N11—C12—C17	−179.94 (14)	C24—C25—C26—N21	0.5 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C24—H24···O1^i	0.95	2.58	3.531 (2)	176
C27—H27A···O2^ii	0.98	2.43	3.371 (2)	161
C14—H14···O4^iii	0.95	2.64	3.5863 (19)	174
C15—H15···O1^iv	0.95	2.64	3.1930 (18)	118
C16—H16···O1^iv	0.95	2.47	3.1278 (17)	126
C17—H17A···O3^v	0.98	2.62	3.4563 (19)	143
C1—H1C···O2^vi	0.98	2.55	3.4560 (18)	154
C2—H2A···O3^vii	0.98	2.41	3.3908 (18)	177
C2—H2B···Cu^viii	0.98	2.94	3.7529 (17)	141

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