Dimerization of a mixed-carbene Pd^II dibromide complex by elemental iodine

A monomeric Pd^II complex bearing a mixed carbocyclic/N-heterocyclic carbene ligand and two bromides was reacted with an excess of elemental iodine, which resulted in the surprising removal of one bromide ligand and dimerization of the mixed-carbene complex to form di-μ-bromido-bis­{[1-(cyclo­hepta-2,4,6-trien-2-yl-1-yl­idene-κC¹)-3-(2,6-diiso­propyl­phen­yl)imidazol-2-yl­idene]palladium(II)} bis­(penta­iodide) di­chloro­methane monosolvate, [Pd₂Br₂(C₂₂H₂₄N₂)₂](I₅)₂·CH₂Cl₂. The dimeric complex features a slightly distorted square-planar core of two Pd^II centres bridged by two bromide ligands, which lie in the same plane as the seven- and five-membered rings of the bidentate carbene ligand. The counter-ions in the single crystal were found to be penta­iodide monoanions featuring their typical V-shape, whereas for the bulk material, a mixture of Br/I inter­halides is proposed.

Computing details

Data collection: APEX3 (Bruker, 2015); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b) and shelXle (Hübschle et al., 2011); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: PLATON (Spek, 2009), enCIFer (Allen et al., 2004) and publCIF (Westrip, 2010).

Di-µ-bromido-bis{[1-(cyclohepta-2,4,6-trien-2-yl-1-ylidene-κC¹)-3-(2,6-diisopropylphenyl)imidazol-4-in-2-ylidene]palladium(II)} bis(pentaiodide) dichloromethane monosolvate

Crystal data

[Pd2Br2(C22H24N2)2](I5)2·CH2Cl2	Z = 1
Mr = 2359.39	F(000) = 1074
Triclinic, P1	Dx = 2.555 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.1277 (10) Å	Cell parameters from 9279 reflections
b = 13.5001 (16) Å	θ = 2.4–28.3°
c = 14.6344 (17) Å	µ = 7.05 mm^−1
α = 113.316 (3)°	T = 100 K
β = 103.239 (3)°	Fragment, red-black
γ = 100.711 (3)°	0.30 × 0.23 × 0.11 mm
V = 1533.0 (3) Å^3

Data collection

Bruker Photon CMOS diffractometer	7307 independent reflections
Radiation source: IMS microsource	6600 reflections with I > 2σ(I)
Helios optic monochromator	Rint = 0.032
Detector resolution: 16 pixels mm^-1	θmax = 27.9°, θmin = 2.4°
phi– and ω–rotation scans	h = −12→12
Absorption correction: multi-scan (SADABS2014; Bruker, 2014)	k = −17→17
Tmin = 0.508, Tmax = 0.746	l = −19→19
52411 measured reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.023	H-atom parameters constrained
wR(F^2) = 0.051	w = 1/[σ^2(Fo^2) + (0.0125P)^2 + 5.9696P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
7307 reflections	Δρmax = 2.73 e Å^−3
284 parameters	Δρmin = −1.50 e Å^−3

Special details

Experimental. Diffractometer operator C. Jandl, scanspeed 5 s per frame, dx 50 mm, 2914 frames measured in 12 data sets, phi-scans with delta_phi = 0.5, omega-scans with delta_omega = 0.5, shutterless mode

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > 2sigma(F²) is used only for calculating -R-factor-obs 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
I1	0.44928 (4)	0.25761 (2)	−0.06905 (2)	0.0395 (1)
I2	0.60969 (3)	0.44761 (2)	0.12738 (2)	0.0206 (1)
I3	0.78107 (3)	0.65254 (2)	0.34424 (2)	0.0258 (1)
I4	1.01616 (3)	0.77990 (2)	0.28338 (2)	0.0172 (1)
I5	1.24828 (3)	0.88864 (2)	0.22710 (2)	0.0301 (1)
Pd1	0.11011 (3)	0.55326 (2)	0.42718 (2)	0.0090 (1)
Br1	−0.10563 (4)	0.38340 (3)	0.38730 (2)	0.0147 (1)
N1	0.3288 (3)	0.6709 (2)	0.3662 (2)	0.0100 (7)
N2	0.3908 (3)	0.7745 (2)	0.5334 (2)	0.0109 (7)
C1	0.1140 (4)	0.5052 (3)	0.2793 (2)	0.0114 (8)
C2	0.0006 (4)	0.4089 (3)	0.1942 (3)	0.0174 (9)
C3	−0.0183 (4)	0.3600 (3)	0.0868 (3)	0.0245 (10)
C4	0.0744 (5)	0.3922 (3)	0.0347 (3)	0.0243 (11)
C5	0.2056 (4)	0.4854 (3)	0.0771 (3)	0.0220 (10)
C6	0.2776 (4)	0.5693 (3)	0.1810 (3)	0.0179 (10)
C7	0.2362 (4)	0.5775 (3)	0.2690 (2)	0.0117 (8)
C8	0.2889 (4)	0.6775 (2)	0.4529 (2)	0.0104 (8)
C9	0.4543 (4)	0.7658 (3)	0.3941 (3)	0.0153 (9)
C10	0.4934 (4)	0.8298 (3)	0.4986 (3)	0.0157 (9)
C11	0.4024 (4)	0.8159 (2)	0.6438 (2)	0.0116 (8)
C12	0.5089 (4)	0.7873 (3)	0.7060 (3)	0.0150 (9)
C13	0.5148 (4)	0.8252 (3)	0.8111 (3)	0.0193 (10)
C14	0.4203 (4)	0.8890 (3)	0.8500 (3)	0.0206 (9)
C15	0.3177 (4)	0.9171 (3)	0.7849 (3)	0.0182 (9)
C16	0.3048 (4)	0.8798 (3)	0.6789 (3)	0.0134 (8)
C17	0.6100 (4)	0.7153 (3)	0.6635 (3)	0.0210 (11)
C18	0.7813 (5)	0.7642 (4)	0.7382 (4)	0.0347 (14)
C19	0.5403 (5)	0.5932 (3)	0.6415 (3)	0.0266 (11)
C20	0.1888 (4)	0.9061 (3)	0.6058 (3)	0.0162 (9)
C21	0.2672 (5)	1.0178 (3)	0.6075 (3)	0.0237 (11)
C22	0.0363 (4)	0.9086 (3)	0.6307 (3)	0.0261 (11)
H2	−0.07670	0.37000	0.21240	0.0210*
H3	−0.10840	0.29490	0.04310	0.0290*
H4	0.04380	0.34430	−0.03900	0.0290*
H5	0.25410	0.49360	0.02850	0.0260*
H6	0.36620	0.62860	0.19360	0.0220*
H9	0.50250	0.78200	0.34840	0.0180*
H10	0.57570	0.89980	0.54120	0.0190*
H13	0.58470	0.80700	0.85640	0.0230*
H14	0.42560	0.91370	0.92150	0.0250*
H15	0.25550	0.96240	0.81310	0.0220*
H17	0.61060	0.71460	0.59500	0.0250*
H18A	0.84560	0.72100	0.70430	0.0520*
H18B	0.78520	0.75910	0.80360	0.0520*
H18C	0.82310	0.84380	0.75450	0.0520*
H19A	0.42990	0.56340	0.59480	0.0400*
H19B	0.54470	0.59090	0.70820	0.0400*
H19C	0.60130	0.54680	0.60750	0.0400*
H20	0.16020	0.84430	0.53240	0.0190*
H21A	0.36280	1.01340	0.58840	0.0350*
H21B	0.29580	1.08030	0.67850	0.0350*
H21C	0.19320	1.03100	0.55680	0.0350*
H22A	−0.03910	0.91600	0.57600	0.0390*
H22B	0.05900	0.97330	0.69950	0.0390*
H22C	−0.00940	0.83810	0.63270	0.0390*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.0519 (2)	0.0320 (1)	0.0260 (1)	0.0014 (1)	0.0128 (1)	0.0103 (1)
I2	0.0217 (1)	0.0253 (1)	0.0241 (1)	0.0102 (1)	0.0132 (1)	0.0158 (1)
I3	0.0282 (1)	0.0254 (1)	0.0270 (1)	0.0111 (1)	0.0116 (1)	0.0125 (1)
I4	0.0208 (1)	0.0156 (1)	0.0129 (1)	0.0091 (1)	0.0021 (1)	0.0047 (1)
I5	0.0271 (1)	0.0315 (1)	0.0237 (1)	−0.0003 (1)	0.0020 (1)	0.0128 (1)
Pd1	0.0120 (1)	0.0078 (1)	0.0084 (1)	0.0023 (1)	0.0055 (1)	0.0041 (1)
Br1	0.0206 (2)	0.0097 (1)	0.0094 (1)	−0.0020 (1)	0.0071 (1)	0.0020 (1)
N1	0.0117 (12)	0.0112 (12)	0.0104 (12)	0.0043 (10)	0.0061 (10)	0.0064 (10)
N2	0.0118 (12)	0.0108 (12)	0.0129 (13)	0.0017 (10)	0.0052 (10)	0.0084 (10)
C1	0.0142 (15)	0.0133 (14)	0.0115 (14)	0.0081 (12)	0.0058 (12)	0.0078 (12)
C2	0.0169 (16)	0.0214 (16)	0.0135 (16)	0.0033 (13)	0.0044 (13)	0.0091 (13)
C3	0.0237 (19)	0.0264 (19)	0.0129 (16)	0.0010 (15)	0.0024 (14)	0.0041 (14)
C4	0.029 (2)	0.032 (2)	0.0109 (16)	0.0116 (16)	0.0075 (14)	0.0076 (15)
C5	0.0272 (19)	0.0322 (19)	0.0147 (16)	0.0130 (16)	0.0128 (15)	0.0138 (15)
C6	0.0208 (17)	0.0222 (17)	0.0180 (17)	0.0087 (14)	0.0123 (14)	0.0120 (14)
C7	0.0122 (14)	0.0144 (14)	0.0125 (14)	0.0078 (12)	0.0058 (12)	0.0075 (12)
C8	0.0124 (14)	0.0105 (14)	0.0134 (14)	0.0063 (11)	0.0063 (12)	0.0081 (12)
C9	0.0175 (16)	0.0150 (15)	0.0191 (16)	0.0035 (12)	0.0100 (13)	0.0118 (13)
C10	0.0161 (16)	0.0135 (15)	0.0190 (16)	0.0021 (12)	0.0079 (13)	0.0089 (13)
C11	0.0141 (15)	0.0077 (13)	0.0099 (14)	−0.0009 (11)	0.0034 (12)	0.0033 (11)
C12	0.0143 (15)	0.0152 (15)	0.0158 (16)	0.0022 (12)	0.0037 (13)	0.0093 (13)
C13	0.0191 (17)	0.0224 (17)	0.0140 (16)	0.0027 (14)	0.0015 (13)	0.0099 (14)
C14	0.0249 (18)	0.0183 (16)	0.0100 (15)	−0.0010 (14)	0.0039 (14)	0.0028 (13)
C15	0.0243 (18)	0.0116 (14)	0.0165 (16)	0.0048 (13)	0.0094 (14)	0.0033 (13)
C16	0.0155 (15)	0.0074 (13)	0.0137 (15)	−0.0003 (11)	0.0032 (12)	0.0040 (12)
C17	0.0241 (18)	0.0295 (19)	0.0226 (18)	0.0157 (15)	0.0126 (15)	0.0186 (16)
C18	0.021 (2)	0.036 (2)	0.052 (3)	0.0127 (17)	0.0126 (19)	0.023 (2)
C19	0.029 (2)	0.0251 (19)	0.029 (2)	0.0134 (16)	0.0139 (17)	0.0112 (16)
C20	0.0179 (16)	0.0103 (14)	0.0200 (17)	0.0045 (12)	0.0062 (13)	0.0065 (13)
C21	0.0256 (19)	0.0215 (17)	0.031 (2)	0.0079 (15)	0.0095 (16)	0.0185 (16)
C22	0.0229 (19)	0.0251 (19)	0.038 (2)	0.0108 (15)	0.0123 (17)	0.0191 (17)

Geometric parameters (Å, º)

I1—I2	2.7975 (5)	C16—C20	1.521 (6)
I2—I3	3.0561 (5)	C17—C18	1.529 (6)
I3—I4	3.0117 (5)	C17—C19	1.524 (6)
I4—I5	2.8147 (5)	C20—C22	1.520 (5)
Pd1—Br1	2.4925 (6)	C20—C21	1.532 (6)
Pd1—C1	2.010 (3)	C2—H2	0.9500
Pd1—C8	1.954 (3)	C3—H3	0.9500
Pd1—Br1^i	2.5160 (5)	C4—H4	0.9500
N1—C8	1.373 (4)	C5—H5	0.9500
N1—C9	1.395 (5)	C6—H6	0.9500
N1—C7	1.400 (4)	C9—H9	0.9500
N2—C8	1.339 (4)	C10—H10	0.9500
N2—C10	1.398 (5)	C13—H13	0.9500
N2—C11	1.456 (4)	C14—H14	0.9500
C1—C7	1.417 (6)	C15—H15	0.9500
C1—C2	1.393 (5)	C17—H17	1.0000
C2—C3	1.396 (5)	C18—H18C	0.9800
C3—C4	1.381 (6)	C18—H18A	0.9800
C4—C5	1.373 (6)	C18—H18B	0.9800
C5—C6	1.389 (5)	C19—H19B	0.9800
C6—C7	1.393 (5)	C19—H19C	0.9800
C9—C10	1.342 (5)	C19—H19A	0.9800
C11—C12	1.391 (5)	C20—H20	1.0000
C11—C16	1.395 (5)	C21—H21A	0.9800
C12—C17	1.517 (6)	C21—H21B	0.9800
C12—C13	1.400 (5)	C21—H21C	0.9800
C13—C14	1.387 (6)	C22—H22B	0.9800
C14—C15	1.392 (6)	C22—H22C	0.9800
C15—C16	1.396 (5)	C22—H22A	0.9800
I1—I2—I3	178.729 (12)	C1—C2—H2	115.00
I2—I3—I4	97.863 (13)	C3—C2—H2	115.00
I3—I4—I5	176.004 (11)	C2—C3—H3	115.00
Br1—Pd1—C1	97.19 (11)	C4—C3—H3	115.00
Br1—Pd1—C8	175.06 (10)	C5—C4—H4	116.00
Br1—Pd1—Br1^i	83.488 (13)	C3—C4—H4	116.00
Br1^i—Pd1—C8	99.34 (8)	C4—C5—H5	115.00
Br1^i—Pd1—C1	179.08 (12)	C6—C5—H5	115.00
C1—Pd1—C8	80.03 (14)	C5—C6—H6	116.00
Pd1—Br1—Pd1^i	96.513 (13)	C7—C6—H6	116.00
C7—N1—C9	132.4 (3)	N1—C9—H9	127.00
C7—N1—C8	116.9 (3)	C10—C9—H9	127.00
C8—N1—C9	110.6 (3)	N2—C10—H10	126.00
C8—N2—C10	110.8 (3)	C9—C10—H10	126.00
C8—N2—C11	125.8 (3)	C14—C13—H13	120.00
C10—N2—C11	123.3 (3)	C12—C13—H13	119.00
C2—C1—C7	123.6 (3)	C13—C14—H14	120.00
Pd1—C1—C2	121.2 (3)	C15—C14—H14	120.00
Pd1—C1—C7	115.2 (2)	C14—C15—H15	119.00
C1—C2—C3	130.8 (4)	C16—C15—H15	120.00
C2—C3—C4	129.6 (4)	C18—C17—H17	108.00
C3—C4—C5	127.5 (4)	C19—C17—H17	108.00
C4—C5—C6	129.2 (4)	C12—C17—H17	108.00
C5—C6—C7	128.2 (4)	C17—C18—H18B	110.00
C1—C7—C6	131.0 (3)	H18A—C18—H18C	109.00
N1—C7—C6	117.2 (3)	C17—C18—H18C	109.00
N1—C7—C1	111.8 (3)	H18A—C18—H18B	109.00
Pd1—C8—N1	116.1 (2)	C17—C18—H18A	109.00
Pd1—C8—N2	139.0 (2)	H18B—C18—H18C	110.00
N1—C8—N2	105.0 (3)	C17—C19—H19C	110.00
N1—C9—C10	106.2 (3)	H19A—C19—H19C	110.00
N2—C10—C9	107.5 (3)	H19B—C19—H19C	109.00
N2—C11—C16	117.7 (3)	H19A—C19—H19B	109.00
N2—C11—C12	117.3 (3)	C17—C19—H19A	109.00
C12—C11—C16	125.0 (3)	C17—C19—H19B	109.00
C11—C12—C13	116.3 (3)	C22—C20—H20	107.00
C11—C12—C17	123.0 (3)	C16—C20—H20	107.00
C13—C12—C17	120.6 (4)	C21—C20—H20	108.00
C12—C13—C14	121.0 (4)	C20—C21—H21B	109.00
C13—C14—C15	120.4 (4)	H21A—C21—H21C	110.00
C14—C15—C16	121.0 (4)	C20—C21—H21C	109.00
C15—C16—C20	121.6 (4)	H21A—C21—H21B	109.00
C11—C16—C20	122.1 (3)	C20—C21—H21A	109.00
C11—C16—C15	116.3 (3)	H21B—C21—H21C	109.00
C12—C17—C18	111.9 (3)	C20—C22—H22C	109.00
C12—C17—C19	111.1 (3)	H22A—C22—H22C	109.00
C18—C17—C19	110.2 (4)	H22B—C22—H22C	109.00
C21—C20—C22	110.6 (4)	H22A—C22—H22B	109.00
C16—C20—C21	110.5 (3)	C20—C22—H22A	110.00
C16—C20—C22	113.0 (3)	C20—C22—H22B	109.00
C1—Pd1—Br1—Pd1^i	−179.38 (11)	Pd1—C1—C7—N1	−1.3 (4)
Br1^i—Pd1—Br1—Pd1^i	0.00 (4)	Pd1—C1—C7—C6	177.8 (4)
Br1—Pd1—C1—C2	7.2 (3)	C2—C1—C7—N1	177.1 (4)
Br1—Pd1—C1—C7	−174.4 (3)	C2—C1—C7—C6	−3.9 (7)
C8—Pd1—C1—C2	−177.0 (4)	C1—C2—C3—C4	2.2 (8)
C8—Pd1—C1—C7	1.5 (3)	C2—C3—C4—C5	−3.6 (8)
C1—Pd1—C8—N1	−1.3 (3)	C3—C4—C5—C6	0.2 (8)
C1—Pd1—C8—N2	177.5 (4)	C4—C5—C6—C7	2.1 (8)
Br1^i—Pd1—C8—N1	179.4 (2)	C5—C6—C7—N1	179.7 (4)
Br1^i—Pd1—C8—N2	−1.8 (4)	C5—C6—C7—C1	0.7 (8)
Br1—Pd1—Br1^i—Pd1^i	0.00 (4)	N1—C9—C10—N2	−0.7 (4)
C8—Pd1—Br1^i—Pd1^i	−175.91 (10)	N2—C11—C12—C13	−178.2 (3)
C8—N1—C7—C1	0.2 (5)	N2—C11—C12—C17	−0.5 (5)
C8—N1—C7—C6	−179.0 (3)	C16—C11—C12—C13	0.9 (6)
C9—N1—C7—C1	−176.1 (4)	C16—C11—C12—C17	178.6 (4)
C9—N1—C7—C6	4.7 (6)	N2—C11—C16—C15	179.3 (3)
C7—N1—C8—Pd1	1.0 (4)	N2—C11—C16—C20	0.2 (5)
C7—N1—C8—N2	−178.2 (3)	C12—C11—C16—C15	0.2 (6)
C9—N1—C8—Pd1	178.1 (2)	C12—C11—C16—C20	−178.9 (4)
C9—N1—C8—N2	−1.1 (4)	C11—C12—C13—C14	−0.9 (6)
C7—N1—C9—C10	177.6 (4)	C17—C12—C13—C14	−178.6 (4)
C8—N1—C9—C10	1.1 (4)	C11—C12—C17—C18	135.5 (4)
C10—N2—C8—Pd1	−178.3 (3)	C11—C12—C17—C19	−100.8 (4)
C10—N2—C8—N1	0.6 (4)	C13—C12—C17—C18	−46.9 (6)
C11—N2—C8—Pd1	5.1 (6)	C13—C12—C17—C19	76.8 (5)
C11—N2—C8—N1	−176.1 (3)	C12—C13—C14—C15	−0.3 (6)
C8—N2—C10—C9	0.1 (4)	C13—C14—C15—C16	1.5 (6)
C11—N2—C10—C9	176.8 (3)	C14—C15—C16—C11	−1.4 (6)
C8—N2—C11—C12	92.3 (4)	C14—C15—C16—C20	177.7 (4)
C8—N2—C11—C16	−86.9 (4)	C11—C16—C20—C21	−90.6 (5)
C10—N2—C11—C12	−84.0 (4)	C11—C16—C20—C22	144.8 (4)
C10—N2—C11—C16	96.9 (4)	C15—C16—C20—C21	90.3 (5)
Pd1—C1—C2—C3	−179.4 (4)	C15—C16—C20—C22	−34.3 (6)
C7—C1—C2—C3	2.4 (7)

Symmetry code: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···Br1	0.95	2.57	3.308 (4)	135
C17—H17···N2	1.00	2.42	2.885 (5)	108
C20—H20···N2	1.00	2.46	2.881 (5)	105
C4—H4···I4^ii	0.95	3.15	4.088 (4)	170
C5—H5···I2^ii	0.95	3.12	4.062 (5)	171

Symmetry code: (ii) −x+1, −y+1, −z.