A head-to-head isomer of di-μ-α-pyrrolidinonato-bis­[cis-diamminebromo­platinum(III)] dinitrate

In the title compound, [Pt₂Br₂(C₄H₆NO)₂(NH₃)₄](NO₃)₂, the intradimer Pt—Pt distance is 2.6476 (4) Å. The axial Pt^III—Br bond distances at the N₄- and N₂O₂-coordinated sites are 2.5647 (9) and 2.5889 (8) Å, respectively. The two Pt coordination planes are tilted by 18.1 (3)°, and the average torsional twist of the ligands about the Pt—Pt axis is estimated as 1.0°.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.012 Å
• Disorder in solvent or counterion
• R factor = 0.036
• wR factor = 0.092
• Data-to-parameter ratio = 24.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



PLAT_302  Alert C Anion/Solvent Disorder .........................      33.00 Perc.


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

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S1. Comment

The Pt^III ions are generally given as a result of two-electron one-step oxidation of dinuclear Pt^II complexes. The electrochemistry of such Pt^III dimers was first investigated on the α-pyridonate-bridged cis-diammineplatinum(III) dimers, [Pt^III₂(NH₃)₄(µ-α-pyridonato)₂L₂]^{4+ _{(L is an axial ligand, such as OH}2_{, NO}3}-^{, NO2}-^{, Cl}-^{, Br}-^{, etc.; Hollis & Lippard, 1983). It should be noted here that two geometrical isomers, head-to-head (HH) and head-to-tail (HT) isomers, are possible due to the asymmetric feature of the bridging amidate ligands (hereafter, HH and HT will be used as prefixes to distinguish these two isomers). Upon oxidation of Pt}II^{2 _{into Pt}}III^{2_{, a single Pt—Pt bond is formed between the two 5 d}}7 ^{centres and 0.3–0.4 Å of shortening in the Pt—Pt distance is induced. Moreover, the Pt2}III ^{cores generally accept two additional ligands at the axial sites. As far as the doubly bridged dimers mentioned above are concerned, around 21 crystal structures have been determined crystallographically (see, for example, Matsumoto & Sakai, 1999). Six compounds of them are those which possess one or two halide ions at the axial sites, in which _{α-pyridonate, α-pyrrolidinonate, and 1-methyluracilate are used as the bridging ligands. As for the α-pyrrolidinonate family investigated in this report, mono- and dichloro-coordinated HH dimers were previously reported by the authors (Sakai et al., 1998). On the other hand, only one bromo compound, HT-[Pt}}III^{2_(NH3₎4_{(µ-α-pyridonato)}2_Br2_]}2+, has been reported by now (Hollis et al., 1983). Here we report the crystal structure of HH-[Pt^III₂(NH₃)₄(µ-α-pyrrolidinonato)₂Br₂](NO₃)₂, (I).

The crystal of (I) is isomorphous to that of the dichloro analog, HH-[Pt^III₂(NH₃)₄(µ-α-pyrrolidinonato)₂Cl₂](NO₃)₂ [(II); Sakai et al., 1998]. The cell volume of (I) [V = 1052.94 (11) ų] is larger than that reported for (II) [V = 1026.8 (4) ų], reflecting a larger ionic radius of Br compared to that of Cl. The intradimer Pt—Pt distance [2.6476 (4) Å] is by ca 0.1 Å longer than that reported for (II) [2.6366 (7) Å], which must be interpreted in terms of the difference between Cl and Br either in the trans influence or in the electronegativity. If the former is a predominant factor, the Pt—Pt bond distance is expected to be longer in the Cl system, for Cl has a stronger trans influence compared to Br. But this is not the case. If the latter is operating, the net charge (corresponding to the 'net oxidation state') in the Cl system is expected to be higher than that in the Br system. Since the Pt—Pt distance is shortened upon oxidation of Pt^II₂ into Pt₂^III, the higher net oxidation state would cause shortening in the Pt—Pt distance. Thus the electronegativity seems operating. The Pt^III—Br distances in (I) (see Table 1) are quite comparable to those reported for HT-[Pt^III₂(NH₃)₄(µ-α-pyridonato)₂Br₂]^{2+ _[Pt}III^{—Br = 2.573 (1) and 2.562 (1) Å; Hollis, Roberts et al., 1983].}

On the other hand, structural features of this class of dimers have been often evaluated by use of the following two structural parameters. One is a dihedral angle between the two Pt coordination planes within a dimeric unit (_{τ), and the other is an average torsional twist of them about the Pt—Pt axis (ω). The values for (I) are estimated as τ = 18.1 (3)° and ω = 1.0°, which are respectively quite comparable to the values of τ = 18.9° and ω = 1.5° in (II). As reported thus far for the related compounds, the two Pt atoms are shifted out of their individual Pt coordination planes in such a manner that they have an attractive interaction toward one another. Atoms Pt1 and Pt2 are respectively shifted from their mean planes defined by four coordinated atoms by 0.079 (3) and 0.017 (3) Å. The crystal packing is stabilized with extensive hydrogen bonds formed either between the ammines and the oxygen atoms of nitrates/amidates and also between the ammines and the Br atoms (see Table 2).}

S2. Experimental

The title compound was prepared in the same manner as reported for the dichloro-coordinated analog (II), HH-[Pt^III₂(NH₃)₄(µ-α-pyrrolidinonato)₂Cl₂](NO₃)₂ (Sakai et al., 1998), except that HBr was used instead of HCl. The dimer compound (0.024 mmol) was dissolved in an aqueous solution prepared by mixing 0.1 M HBr (0.5 ml) and concentrated HNO₃ (0.2 ml). The solution was left at 278 K for a few days to afford (I) as orange needles.

S3. Refinement

One of two nitrate anions was regarded as being disordered over two sites. All the disordered atoms were supposed to have the same isotropic displacement parameter, where the occupation factors were also supposed as 50%. Moreover, the N—O distances were restrained at 1.22 Å, three O···O distances in each disordered nitrate unit were restrained as equal, and each nitrate unit was restrained to be planar. All H atoms were located at their idealized positions as riding atoms (C—H = 0.97 Å and N—H = 0.89 Å). In the final difference Fourier synthesis, most of 20 residual peaks in the range 1.01–2.42 e Å⁻³ were observed within 1.59 Å from the Pt atoms. The deepest hole was located 0.84 Å from Pt2.

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: KENX (Sakai, 2002); software used to prepare material for publication: SHELXL97, TEXSAN (Molecular Structure Corporation, 2001), KENX and ORTEPII (Johnson, 1976).

Figures

Fig. 1. The structure of (I), showing the atom-labeling scheme. Displacement ellipsoids are shown at the 50% probability level. H atoms have been omitted for clarity.

di-µ-α-pyrrolidinonato-bis[cis-diamminebromoplatinum(III)] dinitrate

Crystal data

[Pt2Br2(C4H6NO)2(NH3)4](NO3)2	Z = 2
Mr = 910.35	F(000) = 836
Triclinic, P1	? # Insert any comments here.
Hall symbol: -P 1	Dx = 2.871 Mg m^−3
a = 9.0092 (5) Å	Mo Kα radiation, λ = 0.71069 Å
b = 10.1125 (6) Å	Cell parameters from 2413 reflections
c = 12.0131 (7) Å	θ = 2.6–23.3°
α = 80.164 (1)°	µ = 17.12 mm^−1
β = 78.041 (1)°	T = 293 K
γ = 84.540 (1)°	Needle, orange
V = 1052.94 (11) Å^3	0.15 × 0.07 × 0.07 mm

Data collection

Bruker SMART APEX CCD-detector diffractometer	6122 independent reflections
Radiation source: fine-focus sealed tube	4127 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
Detector resolution: 8.366 pixels mm^-1	θmax = 30.0°, θmin = 1.8°
ω scans	h = −12→12
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −14→14
Tmin = 0.140, Tmax = 0.302	l = −16→16
13222 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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.092	H-atom parameters constrained
S = 0.95	w = 1/[σ^2(Fo^2) + (0.0467P)^2] where P = (Fo^2 + 2Fc^2)/3
6122 reflections	(Δ/σ)max < 0.001
246 parameters	Δρmax = 2.90 e Å^−3
14 restraints	Δρmin = −2.21 e Å^−3

Special details

Experimental. The first 50 frames were rescanned at the end of data collection to evaluate any possible decay phenomenon. Since it was judged to be negligible, no decay correction was applied to the data.

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.

Mean-plane data from final SHELXL refinement run:-

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

6.9668 (0.0126) x − 4.2105 (0.0201) y + 5.6680 (0.0232) z = 3.2944 (0.0105)

* −0.0093 (0.0030) N1 * 0.0092 (0.0030) N2 * 0.0094 (0.0030) N5 * −0.0093 (0.0030) N6 − 0.0173 (0.0030) Pt2 − 2.6198 (0.0032) Pt1

Rms deviation of fitted atoms = 0.0093

7.9525 (0.0085) x − 3.7555 (0.0188) y + 2.6120 (0.0247) z = 0.2500 (0.0103)

Angle to previous plane (with approximate e.s.d.) = 18.06 (1/4)

* −0.0088 (0.0028) O1 * 0.0087 (0.0028) O2 * 0.0087 (0.0028) N3 * −0.0087 (0.0028) N4 0.0793 (0.0028) Pt1 2.7044 (0.0028) Pt2

Rms deviation of fitted atoms = 0.0087

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	Occ. (<1)
Pt1	0.12639 (3)	0.32007 (2)	0.20144 (2)	0.02349 (8)
Pt2	0.37489 (3)	0.18378 (2)	0.25391 (2)	0.02310 (8)
Br1	−0.12962 (9)	0.44849 (8)	0.17478 (8)	0.0397 (2)
Br2	0.60975 (10)	0.05224 (8)	0.31580 (8)	0.0432 (2)
O1	0.0125 (6)	0.1580 (5)	0.2816 (5)	0.0380 (13)
O2	0.1045 (6)	0.3956 (5)	0.3499 (4)	0.0380 (13)
O3A	0.7579 (15)	0.2108 (13)	0.0094 (11)	0.0727 (15)*	0.50
O3B	0.7069 (13)	0.1906 (14)	−0.0259 (13)	0.0727 (15)*	0.50
O4A	0.9445 (16)	0.2195 (15)	−0.1319 (12)	0.0727 (15)*	0.50
O4B	0.9348 (16)	0.2403 (14)	−0.0960 (14)	0.0727 (15)*	0.50
O5A	0.8010 (15)	0.0537 (12)	−0.0952 (13)	0.0727 (15)*	0.50
O5B	0.8722 (15)	0.0413 (12)	−0.0913 (14)	0.0727 (15)*	0.50
O6	0.4375 (8)	0.2175 (6)	−0.1514 (6)	0.067 (2)
O7	0.4498 (7)	0.3800 (5)	−0.0597 (5)	0.0444 (14)
O8	0.5651 (7)	0.3883 (6)	−0.2363 (5)	0.0503 (16)
N1	0.2286 (7)	0.0386 (5)	0.3273 (5)	0.0287 (13)
N2	0.3245 (7)	0.2807 (6)	0.3926 (5)	0.0300 (13)
N3	0.1339 (8)	0.2503 (6)	0.0512 (5)	0.0394 (16)
H3A	0.1170	0.1632	0.0660	0.059*
H3B	0.2251	0.2620	0.0064	0.059*
H3C	0.0630	0.2952	0.0154	0.059*
N4	0.2242 (7)	0.4924 (5)	0.1178 (5)	0.0334 (14)
H4A	0.2624	0.4837	0.0447	0.050*
H4B	0.2984	0.5078	0.1518	0.050*
H4C	0.1545	0.5609	0.1204	0.050*
N5	0.4332 (7)	0.0841 (6)	0.1130 (5)	0.0374 (15)
H5A	0.4539	0.1437	0.0490	0.056*
H5B	0.3560	0.0372	0.1094	0.056*
H5C	0.5146	0.0286	0.1199	0.056*
N6	0.5275 (7)	0.3269 (6)	0.1740 (6)	0.0342 (15)
H6A	0.5058	0.3999	0.2080	0.051*
H6B	0.5212	0.3485	0.1001	0.051*
H6C	0.6214	0.2941	0.1796	0.051*
N7A	0.8336 (12)	0.1592 (12)	−0.0726 (10)	0.0727 (15)*	0.50
N7B	0.8377 (14)	0.1550 (12)	−0.0710 (8)	0.0727 (15)*	0.50
N8	0.4846 (7)	0.3273 (6)	−0.1497 (6)	0.0349 (15)
C1	0.0869 (9)	0.0517 (7)	0.3227 (6)	0.0303 (16)
C2	0.0066 (9)	−0.0764 (7)	0.3724 (7)	0.0404 (19)
H2A	−0.0702	−0.0639	0.4400	0.048*
H2B	−0.0412	−0.1050	0.3159	0.048*
C3	0.1297 (10)	−0.1759 (8)	0.4029 (9)	0.052 (3)
H3D	0.1445	−0.2467	0.3557	0.062*
H3E	0.1046	−0.2161	0.4833	0.062*
C4	0.2742 (9)	−0.0973 (7)	0.3803 (7)	0.042 (2)
H4D	0.3073	−0.0946	0.4517	0.051*
H4E	0.3561	−0.1380	0.3286	0.051*
C5	0.2070 (8)	0.3641 (7)	0.4115 (6)	0.0296 (15)
C6	0.2020 (11)	0.4280 (9)	0.5168 (7)	0.050 (2)
H6D	0.2191	0.5231	0.4959	0.059*
H6E	0.1049	0.4171	0.5693	0.059*
C7	0.3290 (12)	0.3526 (10)	0.5695 (9)	0.065 (3)
H7A	0.3916	0.4145	0.5894	0.078*
H7B	0.2888	0.2918	0.6385	0.078*
C8	0.4195 (11)	0.2757 (8)	0.4791 (7)	0.045 (2)
H8A	0.5147	0.3167	0.4445	0.054*
H8B	0.4416	0.1834	0.5123	0.054*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pt1	0.02089 (14)	0.02288 (14)	0.02666 (15)	−0.00121 (10)	−0.00639 (10)	−0.00165 (10)
Pt2	0.02139 (14)	0.02030 (14)	0.02680 (15)	−0.00011 (10)	−0.00470 (10)	−0.00205 (10)
Br1	0.0245 (4)	0.0420 (4)	0.0527 (5)	0.0031 (3)	−0.0134 (3)	−0.0028 (4)
Br2	0.0342 (5)	0.0385 (4)	0.0569 (5)	0.0091 (3)	−0.0172 (4)	−0.0036 (4)
O1	0.028 (3)	0.029 (3)	0.050 (4)	−0.004 (2)	−0.003 (2)	0.009 (2)
O2	0.034 (3)	0.051 (3)	0.032 (3)	0.013 (2)	−0.014 (2)	−0.014 (2)
O6	0.092 (6)	0.041 (4)	0.074 (5)	−0.023 (4)	−0.023 (4)	−0.007 (3)
O7	0.053 (4)	0.048 (3)	0.031 (3)	0.004 (3)	−0.006 (3)	−0.008 (3)
O8	0.057 (4)	0.056 (4)	0.035 (3)	−0.016 (3)	−0.002 (3)	−0.003 (3)
N1	0.033 (3)	0.020 (3)	0.031 (3)	−0.003 (2)	−0.003 (3)	0.000 (2)
N2	0.034 (4)	0.029 (3)	0.028 (3)	0.009 (3)	−0.011 (3)	−0.010 (2)
N3	0.038 (4)	0.043 (4)	0.040 (4)	−0.001 (3)	−0.013 (3)	−0.008 (3)
N4	0.034 (4)	0.025 (3)	0.040 (4)	0.002 (3)	−0.009 (3)	−0.001 (3)
N5	0.040 (4)	0.034 (3)	0.035 (4)	0.007 (3)	0.000 (3)	−0.009 (3)
N6	0.025 (3)	0.029 (3)	0.045 (4)	−0.005 (3)	−0.002 (3)	0.001 (3)
N8	0.040 (4)	0.032 (3)	0.035 (4)	−0.003 (3)	−0.008 (3)	−0.010 (3)
C1	0.034 (4)	0.025 (4)	0.031 (4)	−0.002 (3)	−0.006 (3)	−0.003 (3)
C2	0.040 (5)	0.030 (4)	0.046 (5)	−0.011 (3)	0.002 (4)	0.001 (3)
C3	0.046 (5)	0.024 (4)	0.077 (7)	−0.012 (4)	−0.003 (5)	0.009 (4)
C4	0.048 (5)	0.022 (4)	0.050 (5)	−0.002 (3)	−0.008 (4)	0.010 (3)
C5	0.035 (4)	0.027 (4)	0.027 (4)	−0.002 (3)	−0.003 (3)	−0.008 (3)
C6	0.061 (6)	0.056 (6)	0.037 (5)	0.010 (4)	−0.016 (4)	−0.022 (4)
C7	0.069 (7)	0.079 (7)	0.059 (7)	0.022 (6)	−0.035 (6)	−0.033 (5)
C8	0.059 (6)	0.042 (5)	0.043 (5)	0.007 (4)	−0.031 (4)	−0.010 (4)

Geometric parameters (Å, º)

Pt1—Pt2	2.6476 (4)	C3—C4	1.543 (11)
Pt1—Br1	2.5889 (8)	C5—C6	1.506 (10)
Pt2—Br2	2.5647 (9)	C6—C7	1.504 (12)
Pt1—O1	2.009 (5)	C7—C8	1.500 (12)
Pt1—O2	2.023 (5)	N3—H3A	0.8900
Pt1—N3	2.034 (6)	N3—H3B	0.8900
Pt1—N4	2.036 (5)	N3—H3C	0.8900
Pt2—N2	2.025 (6)	N4—H4A	0.8900
Pt2—N1	2.028 (5)	N4—H4B	0.8900
Pt2—N6	2.065 (5)	N4—H4C	0.8900
Pt2—N5	2.067 (6)	N5—H5A	0.8900
O1—C1	1.291 (8)	N5—H5B	0.8900
O2—C5	1.284 (9)	N5—H5C	0.8900
O3A—N7A	1.240 (9)	N6—H6A	0.8900
O4A—N7A	1.246 (9)	N6—H6B	0.8900
O4B—N7A	1.241 (19)	N6—H6C	0.8900
O5A—N7A	1.220 (9)	C2—H2A	0.9700
O3B—N7B	1.238 (9)	C2—H2B	0.9700
O4B—N7B	1.244 (9)	C3—H3D	0.9700
O5B—N7B	1.214 (9)	C3—H3E	0.9700
O6—N8	1.231 (7)	C4—H4D	0.9700
O7—N8	1.255 (8)	C4—H4E	0.9700
O8—N8	1.242 (8)	C6—H6D	0.9700
N1—C1	1.283 (9)	C6—H6E	0.9700
N1—C4	1.471 (8)	C7—H7A	0.9700
N2—C5	1.296 (9)	C7—H7B	0.9700
N2—C8	1.469 (9)	C8—H8A	0.9700
C1—C2	1.514 (9)	C8—H8B	0.9700
C2—C3	1.486 (11)
O1—Pt1—O2	92.4 (2)	C7—C6—C5	103.5 (7)
O1—Pt1—N3	87.3 (2)	C8—C7—C6	105.4 (7)
O2—Pt1—N3	176.0 (2)	N2—C8—C7	105.9 (7)
O1—Pt1—N4	175.0 (2)	Pt1—N3—H3A	109.5
O2—Pt1—N4	87.7 (2)	Pt1—N3—H3B	109.5
N3—Pt1—N4	92.3 (3)	H3A—N3—H3B	109.5
O1—Pt1—Br1	89.17 (15)	Pt1—N3—H3C	109.5
O2—Pt1—Br1	87.82 (14)	H3A—N3—H3C	109.5
N3—Pt1—Br1	88.21 (19)	H3B—N3—H3C	109.5
N4—Pt1—Br1	85.84 (17)	Pt1—N4—H4A	109.5
O1—Pt1—Pt2	87.17 (15)	Pt1—N4—H4B	109.5
O2—Pt1—Pt2	86.99 (14)	H4A—N4—H4B	109.5
N3—Pt1—Pt2	96.96 (18)	Pt1—N4—H4C	109.5
N4—Pt1—Pt2	97.82 (17)	H4A—N4—H4C	109.5
Br1—Pt1—Pt2	173.52 (2)	H4B—N4—H4C	109.5
N2—Pt2—N1	93.3 (2)	Pt2—N5—H5A	109.5
N2—Pt2—N6	88.9 (2)	Pt2—N5—H5B	109.5
N1—Pt2—N6	177.7 (2)	H5A—N5—H5B	109.5
N2—Pt2—N5	178.3 (2)	Pt2—N5—H5C	109.5
N1—Pt2—N5	87.6 (2)	H5A—N5—H5C	109.5
N6—Pt2—N5	90.2 (3)	H5B—N5—H5C	109.5
N2—Pt2—Br2	94.04 (17)	Pt2—N6—H6A	109.5
N1—Pt2—Br2	95.66 (17)	Pt2—N6—H6B	109.5
N6—Pt2—Br2	83.70 (17)	H6A—N6—H6B	109.5
N5—Pt2—Br2	84.39 (18)	Pt2—N6—H6C	109.5
N2—Pt2—Pt1	83.33 (17)	H6A—N6—H6C	109.5
N1—Pt2—Pt1	83.15 (17)	H6B—N6—H6C	109.5
N6—Pt2—Pt1	97.60 (17)	C3—C2—H2A	110.9
N5—Pt2—Pt1	98.26 (18)	C1—C2—H2A	110.9
Br2—Pt2—Pt1	177.03 (2)	C3—C2—H2B	110.9
C1—O1—Pt1	119.1 (5)	C1—C2—H2B	110.9
C5—O2—Pt1	119.4 (4)	H2A—C2—H2B	108.9
C1—N1—C4	112.3 (6)	C2—C3—H3D	110.5
C1—N1—Pt2	123.0 (5)	C4—C3—H3D	110.5
C4—N1—Pt2	124.4 (5)	C2—C3—H3E	110.5
C5—N2—C8	110.9 (6)	C4—C3—H3E	110.5
C5—N2—Pt2	123.3 (5)	H3D—C3—H3E	108.7
C8—N2—Pt2	125.6 (5)	N1—C4—H4D	110.8
O5A—N7A—O3A	121.7 (8)	C3—C4—H4D	110.8
O3B—N7A—O4B	120.8 (14)	N1—C4—H4E	110.8
O5A—N7A—O4A	120.9 (8)	C3—C4—H4E	110.8
O3A—N7A—O4A	117.4 (8)	H4D—C4—H4E	108.9
O5B—N7B—O3B	122.2 (8)	C7—C6—H6D	111.1
O5B—N7B—O4B	120.1 (8)	C5—C6—H6D	111.1
O3B—N7B—O4B	117.8 (8)	C7—C6—H6E	111.1
O6—N8—O8	121.1 (7)	C5—C6—H6E	111.1
O6—N8—O7	119.9 (7)	H6D—C6—H6E	109.0
O8—N8—O7	119.0 (6)	C8—C7—H7A	110.7
N1—C1—O1	127.3 (7)	C6—C7—H7A	110.7
N1—C1—C2	112.5 (6)	C8—C7—H7B	110.7
O1—C1—C2	120.2 (7)	C6—C7—H7B	110.7
C3—C2—C1	104.2 (6)	H7A—C7—H7B	108.8
C2—C3—C4	106.1 (6)	N2—C8—H8A	110.6
N1—C4—C3	104.6 (6)	C7—C8—H8A	110.6
O2—C5—N2	126.8 (7)	N2—C8—H8B	110.6
O2—C5—C6	120.9 (7)	C7—C8—H8B	110.6
N2—C5—C6	112.3 (7)	H8A—C8—H8B	108.7
O1—Pt1—Pt2—N1	0.1 (2)	C1—N1—C4—C3	3.7 (9)
O2—Pt1—Pt2—N2	−1.5 (2)	C2—C3—C4—N1	−5.6 (9)
N4—Pt1—Pt2—N6	−2.3 (2)	C8—N2—C5—O2	177.4 (7)
N3—Pt1—Pt2—N5	−0.3 (2)	C8—N2—C5—C6	−1.1 (10)
C4—N1—C1—O1	179.9 (7)	O2—C5—C6—C7	173.7 (8)
C4—N1—C1—C2	−0.3 (9)	N2—C5—C6—C7	−7.7 (10)
N1—C1—C2—C3	−3.4 (9)	C5—C6—C7—C8	12.9 (10)
O1—C1—C2—C3	176.5 (7)	C5—N2—C8—C7	9.6 (10)
C1—C2—C3—C4	5.3 (9)	C6—C7—C8—N2	−13.8 (10)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3C···Br1	0.89	2.86	3.242 (6)	107
N3—H3A···O1	0.89	2.56	2.790 (8)	96
N3—H3B···O7	0.89	2.37	3.183 (9)	152
N4—H4C···Br1	0.89	2.81	3.176 (6)	107
N4—H4A···O7	0.89	2.18	2.927 (8)	141
N5—H5C···Br2	0.89	2.72	3.132 (7)	110
N5—H5A···O3A	0.89	2.81	3.226 (14)	110
N5—H5A···O3B	0.89	2.33	2.866 (14)	119
N5—H5A···O6	0.89	2.43	3.225 (9)	150
N6—H6C···Br2	0.89	2.70	3.111 (6)	110
N6—H6C···O3A	0.89	2.40	2.868 (13)	113
N6—H6B···O3B	0.89	2.63	3.063 (14)	111
N6—H6B···O7	0.89	2.11	2.982 (9)	165
N3—H3A···O5A^i	0.89	2.24	3.051 (14)	151
N3—H3A···O5B^i	0.89	2.03	2.910 (13)	168
N3—H3C···O4A^ii	0.89	2.50	3.120 (17)	127
N3—H3C···O4B^ii	0.89	2.11	2.786 (18)	132
N4—H4C···O3A^iii	0.89	2.64	3.130 (15)	115
N4—H4C···O4A^iii	0.89	2.33	3.170 (17)	158
N4—H4C···O4B^iii	0.89	2.09	2.934 (16)	158
N4—H4B···O7^iii	0.89	2.58	3.217 (8)	129
N4—H4B···O8^iii	0.89	2.19	3.038 (9)	160
N5—H5B···O5A^i	0.89	1.81	2.700 (14)	177
N5—H5C···O6^i	0.89	2.46	3.153 (9)	135
N6—H6A···O7^iii	0.89	2.61	3.053 (8)	112
N6—H6A···O8^iii	0.89	2.24	3.093 (8)	161

Symmetry codes: (i) −x+1, −y, −z; (ii) x−1, y, z; (iii) −x+1, −y+1, −z.