[μ-1,2-Bis(diphenyl­phosphan­yl)-1,2-dimethyl­hydrazine-κ2P:P′]bis­[chlorido­gold(I)]

Kriel, F.H.; Fernandes, M.A.; Coates, J.

doi:10.1107/S1600536810050506

metal-organic compounds

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Volume 67| Part 1| January 2011| Page m42

https://doi.org/10.1107/S1600536810050506

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[μ-1,2-Bis(diphenylphosphanyl)-1,2-dimethylhydrazine-κ²P:P′]bis[chloridogold(I)]

Frederik H. Kriel,^a ^* Manuel A. Fernandes ^b and Judy Coates ^a

^aProject AuTEK, Mintek, Private Bag X3015, Randburg 2125, South Africa, and ^bMolecular Science Institute, School of Chemistry, University of the Witwatersrand, PO Wits, 2050 Johannesburg, South Africa
^*Correspondence e-mail: erikk@mintek.co.za

(Received 16 November 2010; accepted 2 December 2010; online 8 December 2010)

The title compound, [Au₂Cl₂(C₂₆H₂₆N₂P₂)], is formed from a bidentate phosphine ligand complexed to two linearly coordinated gold(I) atoms. The gold(I) atoms are 3.4873 (7) Å apart. The molecule exhibits a crystallographic twofold rotation axis.

Related literature

For the structure of the parent ligand, see: Kriel et al. (2010a ). For the synthesis of the parent ligand and related structures utilising alternative metals, see: Reddy et al. (1994 , 1995 ); Kriel et al. (2010b ). For Au⋯Au interactions, see: Holleman & Wiberg (2001 ). For related gold structures of dppe and dppen (dppe = 1,2-bis(diphenylphosphino)ethane; dppen = 1,2-bis(diphenylphosphino)ethene), see: Eggleston et al. (1985 ) and Jones (1980 ), respectively.

Experimental

Crystal data

[Au₂Cl₂(C₂₆H₂₆N₂P₂)]
M_r = 893.26
Tetragonal, P 4₁ 2₁ 2
a = 10.6720 (14) Å
c = 23.439 (4) Å
V = 2669.5 (7) Å³
Z = 4
Mo Kα radiation
μ = 11.32 mm⁻¹
T = 173 K
0.18 × 0.10 × 0.08 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: integration (SADABS; Bruker, 1999 ) T_min = 0.294, T_max = 0.457
25347 measured reflections
3312 independent reflections
2709 reflections with I > 2σ(I)
R_int = 0.091

Refinement

R[F² > 2σ(F²)] = 0.030
wR(F²) = 0.056
S = 0.98
3312 reflections
154 parameters
H-atom parameters constrained
Δρ_max = 1.43 e Å⁻³
Δρ_min = −0.78 e Å⁻³
Absolute structure: Flack (1983 ), 1332 Friedel pairs
Flack parameter: 0.011 (10)

Data collection: SMART-NT (Bruker, 1998 ); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ) and Mercury (Macrae et al., 2008); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536810050506/br2152sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810050506/br2152Isup2.hkl

checkCIF report

Comment top

In the title compound, gold(I) forms an almost linear complex with a P—Au—Cl angles of 176.34 °. The Au—Au distances is 3.487 Å and is slightly too long to be classified as an aurophilic interaction, which is defined as between 2.7 Å and 3.4 Å (Holleman et al., 2001). Other bond lengths are within expected ranges.

A direct comparison of the title compound and the analogous dppe complex (where dppe = 1,2-bis(diphenylphosphino)ethane); ClAu(dppe)AuCl shows that the preference for the gauche conformation of the hydrazine backbone in the parent ligand (Kriel et al.) may explain the observed intramolecular Au—Au interactions as compared to the intermolecular Au—Au interactions observed in the two polymorphs of ClAu(dppe)AuCl (3.189 Å and 3.221 Å ). The formation of intermolecular Au—Au interactions between dimers of ClAu(dppe)AuCl may be attributed to the different conformation of the ethyl backbone as illustrated by the torsion angles of the two polymorphs (-18.6 ° and 50.7 °) (Eggleston et al., 1985). Intermolecular Au—Au contacts are also observed for the analogous ClAu(dppen)AuCl complex (dppen = 1,2–bis(diphenylphosphino)ethene) (3.05 Å), where the ethene bridge is constrained to a cis conformation by the double bond (Jones, 1980).

The insolubility of the title compound in both non polar and highly polar solvents once crystallized may be a result of the tightly packed parallel helixes, that are formed in the solid state. While the complex readily crystallizes from THF it does not include THF in the structure. This structure exhibits a α-helical packing down the c axis (Figure 2). This unique packing results in parallel helixes that have no voids large enough to include solvent and leads to a stabilizing short contact distance of 2.900 Å between Cl and H(15).

Related literature top

For the structure of the parent ligand, see: Kriel et al. (2010a). For the synthesis of the parent ligand and related structures utilising alternative metals, see: Reddy et al. (1994, 1995); Kriel et al. (2010b). For Au···Au interactions, see: Holleman et al. (2001). For related gold structures of dppe and dppen (dppe = 1,2-bis(diphenylphosphino)ethane; dppen = 1,2-bis(diphenylphosphino)ethene), see: Eggleston et al. (1985) and Jones (1980) respectively.

Experimental top

General procedure

Tetrahydrothiophenegold(I) chloride [(THT)AuCl] was suspended in tetrahydrofuran. 0.5 equivalents of the ligand, bis(diphenylphosphino)-1,2-dimethylhydrazine, dissolved in dicloromethane was added to the stirred suspension. The suspension turned yellow and after a short time micro crystals started to form. The solvent was removed in vacuo to afford the product as a micro-crystalline powder.

Alternatively, the reaction was carried out in dichloromethane to afforded the title compound. By addition of a few drops of tehrahydrofuran it was possible to grow crystals overnight.

Structure description top

For the structure of the parent ligand, see: Kriel et al. (2010a). For the synthesis of the parent ligand and related structures utilising alternative metals, see: Reddy et al. (1994, 1995); Kriel et al. (2010b). For Au···Au interactions, see: Holleman et al. (2001). For related gold structures of dppe and dppen (dppe = 1,2-bis(diphenylphosphino)ethane; dppen = 1,2-bis(diphenylphosphino)ethene), see: Eggleston et al. (1985) and Jones (1980) respectively.

Computing details top

Data collection: SMART-NT (Bruker, 1998); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. Molecular structure of the title compound drawn with displacement ellipsoids at the 50% probability level. Hydrogen atoms have been omitted for clarity.
	Fig. 2. Packing of the title compound as seen down the c axis.

[µ-1,2-Bis(diphenylphosphanyl)-1,2-dimethylhydrazine- κ²P:P']bis[chloridogold(I)] top

Crystal data top

[Au₂Cl₂(C₂₆H₂₆N₂P₂)]	D_x = 2.223 Mg m⁻³
M_r = 893.26	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4₁2₁2	Cell parameters from 7602 reflections
Hall symbol: P 4abw 2nw	θ = 5.2–49.5°
a = 10.6720 (14) Å	µ = 11.32 mm⁻¹
c = 23.439 (4) Å	T = 173 K
V = 2669.5 (7) Å³	Prismic, colourless
Z = 4	0.18 × 0.10 × 0.08 mm
F(000) = 1672

Data collection top

Bruker SMART CCD area-detector diffractometer	3312 independent reflections
Radiation source: fine-focus sealed tube	2709 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.091
phi and ω scans	θ_max = 28.3°, θ_min = 2.1°
Absorption correction: integration (SADABS; Bruker, 1999)	h = −14→14
T_min = 0.294, T_max = 0.457	k = −11→14
25347 measured reflections	l = −31→31

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.030	H-atom parameters constrained
wR(F²) = 0.056	w = 1/[σ²(F_o²) + (0.0218P)²] where P = (F_o² + 2F_c²)/3
S = 0.98	(Δ/σ)_max < 0.001
3312 reflections	Δρ_max = 1.43 e Å⁻³
154 parameters	Δρ_min = −0.78 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 1332 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.011 (10)

Crystal data top

[Au₂Cl₂(C₂₆H₂₆N₂P₂)]	Z = 4
M_r = 893.26	Mo Kα radiation
Tetragonal, P4₁2₁2	µ = 11.32 mm⁻¹
a = 10.6720 (14) Å	T = 173 K
c = 23.439 (4) Å	0.18 × 0.10 × 0.08 mm
V = 2669.5 (7) Å³

Data collection top

Bruker SMART CCD area-detector diffractometer	3312 independent reflections
Absorption correction: integration (SADABS; Bruker, 1999)	2709 reflections with I > 2σ(I)
T_min = 0.294, T_max = 0.457	R_int = 0.091
25347 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.030	H-atom parameters constrained
wR(F²) = 0.056	Δρ_max = 1.43 e Å⁻³
S = 0.98	Δρ_min = −0.78 e Å⁻³
3312 reflections	Absolute structure: Flack (1983), 1332 Friedel pairs
154 parameters	Absolute structure parameter: 0.011 (10)
0 restraints

Special details top

Experimental. Reaction: bis(diphenylphosphino)-1,2-dimethylhydrazine: 146 mg (0.34 mmol), (THT)AuCl: 200 mg (0.68 mmol), THF: 2 ml, DCM: 5 ml, Yield: 89% Grey crystals or white precipitate. Crystals are insoluble in organic and highly polar solvents. ¹H NMR: (CDCl₃, 300 MHz) δH 7.85 (dd, Arom, J (¹H-³¹P) = 13.2, J (¹H-¹H) = 8.1), 7.52 (t, Arom, J (¹H-¹H) = 9.40 Hz), 7.40 (dd, Arom, J (¹H-³¹P) = 17.7, J (¹H-¹H) = 7.4), 2.76 (d, CH3, ³J = 7.8 Hz). ¹³C NMR: Compound too insoluble in NMR solvents. ³¹P NMR: (CDCl₃, 121 MHz) δP 87.1. MS: No useful information could be obtained. EA: Calc: (Au₂Cl₂P₂N₂C₂₆H₂₆) C 34.96%, H 2.93%, N 3.14% Found: C 35.29%, H 2.93%, N 3.13%. MP: 228 - 230 °C.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
C1	0.0733 (7)	0.2483 (7)	−0.0265 (3)	0.0412 (18)
H1A	0.0168	0.3183	−0.0269	0.062*
H1B	0.0377	0.1816	−0.0043	0.062*
H1C	0.0871	0.2199	−0.0649	0.062*
C11	0.1070 (6)	0.3372 (6)	0.1127 (2)	0.0242 (14)
C12	−0.0234 (7)	0.3312 (6)	0.1112 (2)	0.0272 (16)
H12	−0.0658	0.3546	0.0782	0.033*
C13	−0.0888 (7)	0.2919 (6)	0.1571 (3)	0.0367 (17)
H13	−0.1758	0.2884	0.1555	0.044*
C14	−0.0262 (7)	0.2563 (6)	0.2072 (3)	0.0378 (19)
H14	−0.0719	0.2331	0.2393	0.045*
C15	0.1029 (8)	0.2556 (6)	0.2089 (2)	0.0325 (17)
H15	0.1450	0.2271	0.2411	0.039*
C16	0.1693 (6)	0.2981 (6)	0.1618 (3)	0.0277 (16)
H16	0.2564	0.3006	0.1630	0.033*
C21	0.1195 (6)	0.5279 (6)	0.0255 (3)	0.0248 (15)
C22	0.0479 (6)	0.6049 (6)	0.0614 (2)	0.0315 (16)
H22	0.0321	0.5804	0.0988	0.038*
C23	0.0009 (7)	0.7174 (7)	0.0411 (3)	0.0358 (18)
H23	−0.0455	0.7687	0.0652	0.043*
C24	0.0220 (7)	0.7542 (7)	−0.0142 (3)	0.0387 (19)
H24	−0.0114	0.8291	−0.0276	0.046*
C25	0.0927 (7)	0.6797 (6)	−0.0496 (3)	0.0356 (17)
H25	0.1082	0.7052	−0.0868	0.043*
C26	0.1405 (6)	0.5680 (7)	−0.0303 (3)	0.0311 (16)
H26	0.1877	0.5184	−0.0549	0.037*
N	0.1921 (5)	0.2864 (5)	−0.0014 (2)	0.0235 (12)
P	0.19968 (15)	0.39132 (16)	0.05313 (6)	0.0224 (4)
Cl	0.60720 (16)	0.45361 (16)	0.09865 (6)	0.0346 (4)
Au	0.40052 (2)	0.42768 (2)	0.073875 (9)	0.02472 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.033 (5)	0.046 (5)	0.044 (4)	0.007 (4)	−0.011 (4)	−0.019 (4)
C11	0.024 (4)	0.023 (3)	0.025 (3)	0.005 (3)	0.001 (3)	0.004 (3)
C12	0.033 (4)	0.026 (4)	0.023 (4)	0.001 (3)	−0.002 (3)	0.004 (3)
C13	0.028 (4)	0.028 (4)	0.054 (4)	−0.002 (4)	0.004 (4)	0.003 (3)
C14	0.043 (5)	0.026 (4)	0.045 (4)	−0.010 (4)	0.016 (4)	0.003 (3)
C15	0.057 (5)	0.019 (3)	0.021 (3)	0.009 (4)	−0.003 (3)	0.003 (3)
C16	0.027 (4)	0.022 (4)	0.035 (4)	0.002 (3)	0.002 (3)	−0.008 (3)
C21	0.015 (3)	0.028 (4)	0.031 (3)	−0.005 (3)	−0.008 (3)	0.003 (3)
C22	0.036 (4)	0.034 (4)	0.025 (3)	0.003 (4)	−0.007 (3)	−0.003 (3)
C23	0.027 (4)	0.032 (4)	0.048 (5)	0.006 (3)	−0.001 (3)	−0.015 (4)
C24	0.039 (5)	0.022 (4)	0.055 (5)	0.006 (4)	−0.009 (4)	0.009 (4)
C25	0.034 (4)	0.037 (4)	0.036 (4)	0.004 (4)	−0.001 (3)	0.014 (3)
C26	0.021 (3)	0.040 (4)	0.032 (4)	0.006 (3)	0.002 (3)	−0.007 (4)
N	0.019 (3)	0.024 (3)	0.027 (3)	0.007 (2)	−0.002 (2)	−0.006 (2)
P	0.0200 (8)	0.0247 (10)	0.0226 (7)	0.0048 (8)	−0.0003 (6)	−0.0011 (7)
Cl	0.0263 (9)	0.0423 (10)	0.0353 (8)	−0.0062 (8)	−0.0089 (7)	0.0025 (7)
Au	0.02271 (14)	0.02537 (15)	0.02609 (10)	0.00065 (11)	−0.00336 (11)	−0.00038 (11)

Geometric parameters (Å, º) top

C1—N	1.455 (8)	C21—C26	1.394 (8)
C1—H1A	0.9600	C21—C22	1.402 (9)
C1—H1B	0.9600	C21—P	1.811 (6)
C1—H1C	0.9600	C22—C23	1.386 (9)
C11—C16	1.393 (8)	C22—H22	0.9300
C11—C12	1.394 (9)	C23—C24	1.372 (9)
C11—P	1.805 (6)	C23—H23	0.9300
C12—C13	1.349 (9)	C24—C25	1.374 (9)
C12—H12	0.9300	C24—H24	0.9300
C13—C14	1.404 (9)	C25—C26	1.373 (9)
C13—H13	0.9300	C25—H25	0.9300
C14—C15	1.379 (10)	C26—H26	0.9300
C14—H14	0.9300	N—Nⁱ	1.425 (10)
C15—C16	1.388 (8)	N—P	1.702 (5)
C15—H15	0.9300	P—Au	2.2318 (16)
C16—H16	0.9300	Cl—Au	2.2976 (17)

N—C1—H1A	109.5	C22—C21—P	120.9 (5)
N—C1—H1B	109.5	C23—C22—C21	119.9 (6)
H1A—C1—H1B	109.5	C23—C22—H22	120.1
N—C1—H1C	109.5	C21—C22—H22	120.1
H1A—C1—H1C	109.5	C24—C23—C22	120.8 (6)
H1B—C1—H1C	109.5	C24—C23—H23	119.6
C16—C11—C12	118.9 (6)	C22—C23—H23	119.6
C16—C11—P	118.2 (5)	C23—C24—C25	119.6 (6)
C12—C11—P	122.9 (5)	C23—C24—H24	120.2
C13—C12—C11	120.8 (6)	C25—C24—H24	120.2
C13—C12—H12	119.6	C26—C25—C24	120.5 (6)
C11—C12—H12	119.6	C26—C25—H25	119.7
C12—C13—C14	120.3 (7)	C24—C25—H25	119.7
C12—C13—H13	119.8	C25—C26—C21	121.0 (6)
C14—C13—H13	119.8	C25—C26—H26	119.5
C15—C14—C13	120.0 (6)	C21—C26—H26	119.5
C15—C14—H14	120.0	Nⁱ—N—C1	115.9 (4)
C13—C14—H14	120.0	Nⁱ—N—P	113.3 (5)
C14—C15—C16	119.1 (6)	C1—N—P	121.9 (4)
C14—C15—H15	120.4	N—P—C11	110.1 (3)
C16—C15—H15	120.4	N—P—C21	103.8 (3)
C15—C16—C11	120.8 (6)	C11—P—C21	106.0 (3)
C15—C16—H16	119.6	N—P—Au	108.89 (18)
C11—C16—H16	119.6	C11—P—Au	114.4 (2)
C26—C21—C22	118.1 (6)	C21—P—Au	113.1 (2)
C26—C21—P	120.4 (5)	P—Au—Cl	176.34 (6)

C16—C11—C12—C13	2.0 (10)	C1—N—P—C11	56.8 (6)
P—C11—C12—C13	−179.0 (5)	Nⁱ—N—P—C21	157.7 (3)
C11—C12—C13—C14	0.0 (10)	C1—N—P—C21	−56.3 (6)
C12—C13—C14—C15	−3.1 (10)	Nⁱ—N—P—Au	37.0 (4)
C13—C14—C15—C16	4.1 (10)	C1—N—P—Au	−177.0 (5)
C14—C15—C16—C11	−2.1 (9)	C16—C11—P—N	110.1 (5)
C12—C11—C16—C15	−0.9 (9)	C12—C11—P—N	−69.0 (6)
P—C11—C16—C15	180.0 (5)	C16—C11—P—C21	−138.3 (5)
C26—C21—C22—C23	−0.2 (10)	C12—C11—P—C21	42.7 (6)
P—C21—C22—C23	171.6 (5)	C16—C11—P—Au	−13.0 (6)
C21—C22—C23—C24	0.9 (10)	C12—C11—P—Au	168.0 (5)
C22—C23—C24—C25	−1.3 (11)	C26—C21—P—N	−42.6 (6)
C23—C24—C25—C26	1.1 (11)	C22—C21—P—N	145.7 (5)
C24—C25—C26—C21	−0.5 (10)	C26—C21—P—C11	−158.7 (5)
C22—C21—C26—C25	0.0 (9)	C22—C21—P—C11	29.7 (6)
P—C21—C26—C25	−171.8 (5)	C26—C21—P—Au	75.2 (5)
Nⁱ—N—P—C11	−89.2 (4)	C22—C21—P—Au	−96.5 (5)

Symmetry code: (i) y, x, −z.

Experimental details

Crystal data
Chemical formula	[Au₂Cl₂(C₂₆H₂₆N₂P₂)]
M_r	893.26
Crystal system, space group	Tetragonal, P4₁2₁2
Temperature (K)	173
a, c (Å)	10.6720 (14), 23.439 (4)
V (Å³)	2669.5 (7)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	11.32
Crystal size (mm)	0.18 × 0.10 × 0.08

Data collection
Diffractometer	Bruker SMART CCD area-detector
Absorption correction	Integration (SADABS; Bruker, 1999)
T_min, T_max	0.294, 0.457
No. of measured, independent and observed [I > 2σ(I)] reflections	25347, 3312, 2709
R_int	0.091
(sin θ/λ)_max (Å⁻¹)	0.667

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.056, 0.98
No. of reflections	3312
No. of parameters	154
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.43, −0.78
Absolute structure	Flack (1983), 1332 Friedel pairs
Absolute structure parameter	0.011 (10)

Computer programs: SMART-NT (Bruker, 1998), SAINT-Plus (Bruker, 1999), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008), WinGX (Farrugia, 1999).

Acknowledgements

The authors would like to thank Project AuTEK (Mintek and Harmony) and the University of the Witwatersrand for financial support.

References

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