A new tricarbonyl­rhenium(I) compound incorporating the tridentate ligand N,N-bis­picol­yl-2-ethano­lamine

The title compound, {[N,N-bis­(2-pyridylmeth­yl)­amino]­ethanol-[kappa]³N,N',N''}tricarbonyl­rhenium(I) bromide methanol solvate, [Re(C₁₄H₁₇N₃O)(CO)₃]Br·CH₄O, has been prepared in almost quantitative yield by reacting (NEt₄)₂[Re(CO)₃Br₃] with the ligand N,N-bis­picol­yl-2-ethano­lamine in refluxing methanol. The X-ray structure revealed that the Re(CO)₃N₃ coordination sphere is highly distorted from octa­hedral geometry and that the Re(CO)₃ core is facial. The coordinated ligand forms two five-membered rings, with the pyridine rings in a butterfly formation. The OH group is not involved in metal coordination. The packing of the mol­ecule shows a network of classical O...H-O and Br...H-O, and non-classical Br...H-C and O...H-C hydrogen bonds between the methanol solvate mol­ecules, the metal complex cations and the bromide anions.

S1. Comment

The pendant design of novel ⁹⁹mTc-based radiopharmaceuticals requires the development of suitable bifunctional ligands, which serve two purposes, viz. to hold the radionucleotide securely without leakage in vivo and to provide a side arm for linkage to a bioactive molecule while maintaining maximal integrity of the biomolecule (Liu & Edwards, 1999). We have recently reported the synthesis of a series of M(I) binding ligands (M = Tc and Re) based on a lysine-derived bispicolylamine, referred to as a single amino acid chelate (SAAC), which forms inert complexes with the chemically robust {M(CO)₃}⁺ core (M = ⁹⁹mTc and Re) and which can be incorporated into peptides as if it were a natural amino acid (Banerjee et al., 2002; Levadala et al., 2004; Stephenson et al., 2004).

As a part of continuing efforts to prepare new bifunctional ligands, we have recently investigated the maleimide functionalities for the conjugation of sulfhydryl group containing biomolecules (Banerjee et al., 2004). Recent literature studies have shown that the maleimide derivatives can be conveniently prepared in good yield from the alcohol precursor under Mitsunobu conditions (King et al., 2002). We report here the synthesis and structural characterization of a novel rhenium(I) tricarbonyl compound, (I), incorporating a tridentate ligand bispicolyl-2-ethanolamine (L1) with a free –OH functionality, which is potentially useful as a precursor for the maleimide-containing bifunctional linkers. Compound (I) was prepared quantitatively by the reaction of rhenium precursor (NEt4)₂[Re(CO)₃Br₃] with the ligand under refluxing methanol conditions. A perspective view of (I) is shown in Fig. 1. Selected bond lengths and angles for the compound are given in Table 1. There are two independent molecules in the asymmetric unit. The bond distance and angles of the two molecules are found to be slightly different. The hydrogen-bonded methanol molecules are relatively closer to the Re1 molecule than to the Re2 molecule. These two solvent molecules are responsible for destroying the symmetry of the unit cell and the doubling of the asymmetric unit.

The distorted octahedral coordination environment of Re is defined by the three facially bound CO groups and the secondary amine and pyridine N-atom donors of the ligand. The mirror plane, which contains the OH group, the ethylene backbone, and the Re1—N2, Re1—C3—O3 and Re2—N5, Re2—C19—O7 bonds for the two independent molecules, divides the two pyridine–methylene units symmetrically. The structure of (I) provides an opportunity to observe the effect of rhenium oxidation states on the metal–ligand bond lengths via comparison with [Re(V)O(OCH₂CH₂O)(L1)]ReO₄ [Cambridge Structural Database (CSD; Allen, 2002) code NOMCEX], where L1 serves as an N,N,N-tridentate ligand with a pendant –OH group, the same as in compound (I), with [Re(V)OCl(L1)]PF₆ (CSD code NOMCAT), where L1 acts as an anionic N,N,N,O-tetradentate ligand, and with [Re(V)OCl₂(L1)] (CSD code NOMBOG), where L1 is an anionic N,N,O-tridentate ligand with a pendant pyridine ring (Botha et al., 1998). The Re^I—N_py bond lengths [average 2.171 (6) Å] in (I) lie at the longer end of the range of the Re^V—N_py bond lengths (2.11–2.17 Å), which possibly reveals the contraction of the metal radius upon increase in oxidation state from I to V. However, the Re—N_amine bond distance in [Re(V)O(OCH₂CH₂O)(L1)]ReO₄ is longer than all the other Re^V—N_amine bonds, including that in (I), by ca 0.1 Å, probably as a result of the strong trans influence of the Re═O bond.

The N,N,N-chelating ligand forms two five-membered rings with the two pyridine rings in a butterfly formation. The observed N—Re^I—N bite angles in (I) are comparable to the related bite angles in the previously discussed structures containing L1 (Botha et al., 1998). The packing of the molecules shows antiparallel stacks, with the ligand (L1) moieties and the bromide ions from the adjacent stacks in a face-to-face orientation. The interplanar distance between two pyridine rings of approximately 3.5 Å is of the same order as the π-stacking distances in aromatic and charge-transfer compounds (Batchelor et al., 2000; Glusker et al.,, 1994). The antiparallel arrangement of the ligand moieties facilitates the formation of intermolecular non-classical hydrogen bonding between carbonyl O atoms and pyridine H atoms. Classical intramolecular O–H···O hydrogen bonds were observed between the two methanol molecules and between the methanol molecules and the complexes. Intramolecular classical hydrogen bonds (e.g. O4–H4···Br1, O8–H8···Br2 and O9–H9···Br1) and non-classical intramolecular hydrogen bonding (e.g. C17—H17···Br2, C26—H26B···Br1, C26···H26A···Br2 and C27···H27B···Br1 etc.) are also present (Table 2). In addition side-to-side intermolecular hydrogen bonding is observed between adjacent pyridine rings and bromide ions (e.g. C22—H22···Br1).

S2. Experimental

For the synthesis of the ligand bispicolyl-2-ethanolamine (L1), pyridine-2-aldehyde (7.36 g, 0.069 mol) was added to a solution of 2-aminoethanol (2 g, 0.033 mol in 20 ml dichloroethane) and the solution was stirred for 30 min under an argon atmosphere. The reaction mixture was cooled to 273 K, sodium triacetoxy borohydride (16.08 g, 0.076 mol) was added in small portions at a time and the solution stirred for another hour at room temperature. Thin layer chromatography indicated the completion of the reaction at this time. The reaction mixture was quenched with 2% sodium bicarbonate solution (30 ml) and extracted with dichloromethane (20 ml). The organic layer containing the product was dried over sodium sulfate, concentrated to a 3 ml volume and purified via routine chromatographic techniques using a silica gel column. The product was eluated with MeOH/CH₂Cl₂ (5:95) and dried under reduced pressure to give the ligand as a colorless oil. Yield 6.10 g, 76.76%. For the preparation of (I), to a (NEt₄)₂[Re(CO)₃Br₃] solution (0.1 g, 0.13 mmol in 15 ml me thanol) was added L1 (0.030 g, 0.13 mmol), and the solution was refluxed for 2 h. The colorless reaction mixture was evaporated to dryness and the solid residue thus obtained was dissolved in dichloromethane (10 ml) and extracted with water (3 × 20 ml) to remove all the tetraethyl ammonium bromide obtained as the main side product. The organic layer was concentrated to 2 ml and subjected to chromatographic separation using a silica gel column. The product was eluted with MeOH/CH₂Cl₂ (10:90) and evaporated under vacuum to give a colorless solid product. Yield 67 mg, 87%. Analysis found: C 34.95, H 2.91, N 7.10%; C₁₇H₁₇BrN₃O₄Re requires: C 34.41, H 2.89, N 7.08%. Crystals suitable for single-crystal X-ray diffraction were grown by slow diffusion of a solution of (I) in CH₂Cl₂ into a hexane solution at room temperature.

S3. Refinement

All H atoms were located in difference Fourier maps and refined as riding, with U_iso(H) values of 1.2U_eq(C) (CH and CH₂ H atoms) and 1.5U_eq(C) (CH₃ H atoms). A residual peak of electron density was located 0.83 Å from Re1. This residual density is mainly due to inadequate absorption correction.

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL.

Figures

Fig. 1 A view of (I), with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

{[N,N-bis(2-pyridylmethyl)amino]ethanol-κ³N,N',N''}tricarbonylrhenium(I) bromide methanol solvate

Crystal data

[Re(C14H17N3O)(CO)3]Br·CH4O	F(000) = 2400
Mr = 625.49	Dx = 2.007 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1200 reflections
a = 14.962 (2) Å	θ = 1.5–31.5°
b = 16.577 (3) Å	µ = 7.83 mm^−1
c = 18.117 (3) Å	T = 91 K
β = 112.881 (3)°	Parallelepiped, colorless
V = 4139.9 (11) Å^3	0.22 × 0.14 × 0.09 mm
Z = 8

Data collection

Bruker SMART APEX CCD area-dectector diffractometer	13759 independent reflections
Radiation source: fine-focus sealed tube	10981 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.062
Detector resolution: 512 pixels mm^-1	θmax = 31.5°, θmin = 1.5°
ϕ and ω scans	h = −22→22
Absorption correction: multi-scan (SADABS; Sheldrick, 1997)	k = −24→24
Tmin = 0.278, Tmax = 0.508	l = −26→26
52775 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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.132	H-atom parameters constrained
S = 1.18	w = 1/[σ^2(Fo^2) + (0.0255P)^2 + 54.5922P] where P = (Fo^2 + 2Fc^2)/3
13759 reflections	(Δ/σ)max = 0.001
511 parameters	Δρmax = 6.45 e Å^−3
0 restraints	Δρmin = −2.59 e Å^−3

Special details

Experimental. Synthesis of ligand (L1). Pyridine-2-aldehyde (7.36 g, 0.069 mol) was added to a solution of 2-aminoethanol (2 g, 0.033 mol in 20 ml dichloroethane) and the solution stirred for 30 min under argon atmosphere. The reaction mixture was cooled to 273 K and sodium triacetoxy borohydride (16.08 g, 0.076 mol) added in small portions at a time and the solution stirred for another hour at room temperature. The TLC indicated the completion of the reaction at this time. The reaction mixture was quenched with 30 ml 2% sodium bicarbonate solution and extracted with 20 ml me thylene chloride. The organic layer containing the product was dried over sodium sulfate, concentrated to a 3 ml volume, and purified via routine chromatographic technique using a silica gel column. The product was eluted with 5:95 (MeOH: CH₂Cl₂) and dried under reduced pressure to give the ligand as a colorless oil. Yield: 6.10 g (81.43%). ¹H NMR (CDCl₃, 300 MHz): 8.25(d, J=6.0 Hz, 2H), 7.33(t, J= 9.0 Hz, 2H), 7.15(d, J= 7.8 Hz, 2H), 6.85(t, J=6.0 Hz, 2H), 3.65(s, 4H), 3.45(t, J= 5.1 Hz, 2H), 2.58(t, J= 5.1 Hz, 2H). 13 C NMR (CDCl₃, 300 MHz): 158.98, 148.46, 136.21, 122.78, 121.69, 59.82, 59.502, 53.13. Analysis, found: C 69.30, H 7.08, N 17.30; C₁₄ H₁₇ N₃ O requires: C, 69.11; H, 7.04; N, 17.27.

For (I) IR (KBr, cm⁻¹): 2022, 1919 [fac-Re-(CO)₃]; ¹H NMR (CD₃OD, 300 MHz): 8.45 (d, J = 6.0 Hz, 2H, PyH), 7.66 (t, J = 9.0 Hz, 2H, PyH), 7.43 (d, J = 7.8 Hz, 2H, PyH), 7.14 (t, J = 6.0 Hz, 2H, PyH), 5.42 (dd, J = 16.2 Hz, 2H, PyCH₂), 4.42 (dd, 16.2 Hz, 2H, PyCH₂), 3.95 (t, J = 5.1 Hz, 2H, NCH₂), 3.79 (t, J = 5.1 Hz, 2H, OCH₂). ¹³C NMR (CD₃OD, 300 MHz): 195.42, 194.99 [fac-Re-(CO)₃], 160.39 (2 C, py), 150.70 (2CH, py), 140.11 (2CH, py), 125.50 (2CH, py), 123.69 (2CH, py), 71.87 (2 C, PyCH₂), 67.52 (1 C, NCH₂), 58.23 (1 C, OCH₂).

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. Highest peak 6.45 at 0.0198 0.5921 0.2018 [0.83 A from Re1] Deepest hole −2.59 at 0.4378 0.4885 0.1393 [1.78 A from H35C]

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

	x	y	z	Uiso*/Ueq
Re1	0.44150 (2)	0.174923 (18)	0.640561 (17)	0.01940 (7)
Re2	−0.03551 (2)	0.908034 (17)	0.702824 (16)	0.01708 (7)
Br1	0.83250 (6)	0.10631 (5)	0.91770 (5)	0.02831 (17)
Br2	0.31058 (6)	1.10065 (5)	0.91134 (5)	0.02507 (16)
O1	0.2909 (5)	0.0467 (4)	0.6349 (5)	0.0414 (17)
O2	0.5805 (5)	0.0424 (4)	0.6314 (4)	0.0399 (16)
O3	0.3478 (5)	0.1754 (4)	0.4554 (4)	0.0399 (15)
O4	0.6396 (4)	0.1453 (4)	0.9487 (3)	0.0305 (13)
H4	0.6899	0.1274	0.9444	0.046*
O5	−0.2106 (5)	1.0225 (4)	0.6498 (4)	0.0387 (15)
O6	0.0712 (6)	1.0232 (5)	0.6323 (5)	0.0481 (19)
O7	−0.1332 (5)	0.8351 (4)	0.5341 (4)	0.0368 (15)
O8	0.1065 (4)	1.1543 (3)	0.9252 (3)	0.0249 (11)
H8	0.1602	1.1583	0.9207	0.037*
O9	0.7884 (6)	0.3005 (5)	0.9516 (5)	0.052 (2)
H9	0.8083	0.2551	0.9439	0.078*
O10	0.6007 (7)	0.3261 (6)	0.9782 (6)	0.072 (3)
H10	0.6494	0.3045	0.9742	0.107*
N1	0.5419 (4)	0.2744 (4)	0.6564 (4)	0.0203 (12)
N2	0.5096 (4)	0.1832 (4)	0.7735 (4)	0.0208 (12)
N3	0.3660 (4)	0.2764 (4)	0.6652 (4)	0.0208 (12)
N4	0.0851 (4)	0.8247 (4)	0.7534 (4)	0.0180 (11)
N5	0.0334 (4)	0.9517 (4)	0.8291 (4)	0.0176 (11)
N6	−0.0942 (4)	0.8247 (4)	0.7649 (4)	0.0182 (11)
C1	0.3476 (6)	0.0942 (5)	0.6368 (5)	0.0289 (17)
C2	0.5276 (6)	0.0916 (5)	0.6334 (5)	0.0263 (16)
C3	0.3833 (6)	0.1761 (5)	0.5249 (5)	0.0249 (15)
C4	0.5401 (6)	0.3266 (5)	0.6000 (5)	0.0272 (16)
H4A	0.5022	0.3136	0.5457	0.033*
C5	0.5906 (6)	0.3991 (5)	0.6162 (5)	0.0279 (17)
H5	0.5869	0.4350	0.5742	0.034*
C6	0.6467 (6)	0.4176 (5)	0.6956 (6)	0.0300 (18)
H6	0.6822	0.4666	0.7088	0.036*
C7	0.6504 (6)	0.3639 (5)	0.7557 (5)	0.0281 (17)
H7	0.6888	0.3754	0.8103	0.034*
C8	0.5970 (5)	0.2932 (5)	0.7343 (5)	0.0217 (14)
C9	0.6008 (5)	0.2320 (5)	0.7958 (4)	0.0207 (14)
H9A	0.6132	0.2598	0.8472	0.025*
H9B	0.6558	0.1950	0.8042	0.025*
C10	0.4389 (6)	0.2271 (5)	0.8003 (4)	0.0225 (14)
H10A	0.3918	0.1880	0.8055	0.027*
H10B	0.4747	0.2514	0.8536	0.027*
C11	0.3857 (5)	0.2915 (5)	0.7429 (4)	0.0207 (14)
C12	0.3556 (6)	0.3617 (5)	0.7689 (5)	0.0261 (16)
H12	0.3689	0.3701	0.8240	0.031*
C13	0.3056 (6)	0.4191 (5)	0.7115 (5)	0.0285 (17)
H13	0.2843	0.4676	0.7273	0.034*
C14	0.2870 (6)	0.4057 (5)	0.6324 (5)	0.0282 (16)
H14	0.2543	0.4451	0.5930	0.034*
C15	0.3172 (6)	0.3326 (5)	0.6108 (5)	0.0260 (16)
H15	0.3027	0.3224	0.5558	0.031*
C16	0.5318 (6)	0.1007 (5)	0.8130 (5)	0.0274 (16)
H16A	0.5853	0.0766	0.8011	0.033*
H16B	0.4740	0.0661	0.7872	0.033*
C17	0.5601 (6)	0.0971 (6)	0.9039 (5)	0.0290 (17)
H17A	0.5035	0.1140	0.9157	0.035*
H17B	0.5750	0.0405	0.9217	0.035*
C18	−0.1443 (6)	0.9808 (5)	0.6697 (5)	0.0253 (15)
C19	−0.0952 (6)	0.8606 (5)	0.5978 (5)	0.0251 (15)
C20	0.0307 (6)	0.9812 (5)	0.6578 (5)	0.0293 (17)
C21	0.0981 (6)	0.7554 (5)	0.7185 (5)	0.0253 (16)
H21	0.0567	0.7446	0.6645	0.030*
C22	0.1694 (6)	0.7004 (5)	0.7591 (5)	0.0251 (15)
H22	0.1766	0.6526	0.7330	0.030*
C23	0.2299 (6)	0.7148 (5)	0.8372 (5)	0.0261 (16)
H23	0.2791	0.6771	0.8657	0.031*
C24	0.2183 (5)	0.7848 (4)	0.8738 (5)	0.0220 (14)
H24	0.2588	0.7961	0.9279	0.026*
C25	0.1454 (5)	0.8386 (4)	0.8292 (4)	0.0175 (13)
C26	0.1354 (5)	0.9175 (5)	0.8649 (4)	0.0200 (14)
H26A	0.1807	0.9568	0.8570	0.024*
H26B	0.1544	0.9105	0.9233	0.024*
C27	−0.0260 (5)	0.9200 (5)	0.8729 (4)	0.0213 (14)
H27A	0.0154	0.9167	0.9307	0.026*
H27B	−0.0791	0.9585	0.8664	0.026*
C28	−0.0685 (5)	0.8389 (4)	0.8441 (4)	0.0171 (13)
C29	−0.0866 (5)	0.7837 (5)	0.8946 (4)	0.0214 (14)
H29	−0.0669	0.7944	0.9502	0.026*
C30	−0.1343 (6)	0.7126 (5)	0.8612 (5)	0.0256 (16)
H30	−0.1480	0.6738	0.8939	0.031*
C31	−0.1617 (6)	0.6986 (5)	0.7800 (5)	0.0245 (15)
H31	−0.1946	0.6504	0.7562	0.029*
C32	−0.1404 (5)	0.7554 (5)	0.7347 (4)	0.0214 (14)
H32	−0.1592	0.7454	0.6790	0.026*
C33	0.0405 (5)	1.0421 (4)	0.8374 (4)	0.0207 (14)
H33A	−0.0251	1.0653	0.8094	0.025*
H33B	0.0820	1.0622	0.8102	0.025*
C34	0.0813 (6)	1.0726 (5)	0.9237 (4)	0.0217 (14)
H34A	0.0323	1.0659	0.9474	0.026*
H34B	0.1393	1.0406	0.9560	0.026*
C35	0.5966 (11)	0.4066 (9)	0.9570 (7)	0.065 (4)
H35A	0.6617	0.4302	0.9810	0.097*
H35B	0.5528	0.4353	0.9765	0.097*
H35C	0.5725	0.4112	0.8986	0.097*
C36	0.8667 (9)	0.3505 (9)	0.9893 (10)	0.071 (4)
H36A	0.8457	0.4069	0.9795	0.106*
H36B	0.9168	0.3403	0.9682	0.106*
H36C	0.8931	0.3399	1.0471	0.106*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Re1	0.01870 (13)	0.02209 (14)	0.01595 (12)	−0.00161 (10)	0.00516 (10)	0.00003 (10)
Re2	0.02032 (13)	0.01710 (12)	0.01372 (12)	−0.00114 (10)	0.00653 (10)	−0.00135 (10)
Br1	0.0264 (4)	0.0355 (4)	0.0235 (4)	0.0064 (3)	0.0101 (3)	0.0085 (3)
Br2	0.0234 (3)	0.0271 (4)	0.0257 (4)	0.0009 (3)	0.0105 (3)	0.0016 (3)
O1	0.026 (3)	0.032 (4)	0.062 (5)	−0.006 (3)	0.013 (3)	0.007 (3)
O2	0.035 (3)	0.035 (4)	0.054 (4)	0.006 (3)	0.021 (3)	0.000 (3)
O3	0.049 (4)	0.046 (4)	0.020 (3)	0.001 (3)	0.008 (3)	−0.002 (3)
O4	0.025 (3)	0.043 (4)	0.023 (3)	0.001 (3)	0.009 (2)	0.001 (3)
O5	0.035 (3)	0.031 (3)	0.042 (4)	0.011 (3)	0.005 (3)	0.002 (3)
O6	0.066 (5)	0.045 (4)	0.045 (4)	−0.022 (4)	0.036 (4)	−0.005 (3)
O7	0.053 (4)	0.034 (3)	0.019 (3)	−0.002 (3)	0.009 (3)	0.000 (2)
O8	0.030 (3)	0.018 (3)	0.026 (3)	−0.002 (2)	0.010 (2)	−0.005 (2)
O9	0.059 (5)	0.039 (4)	0.054 (5)	−0.012 (4)	0.017 (4)	−0.008 (4)
O10	0.086 (7)	0.056 (6)	0.053 (5)	0.032 (5)	0.005 (5)	−0.005 (4)
N1	0.018 (3)	0.020 (3)	0.023 (3)	−0.002 (2)	0.008 (2)	0.000 (2)
N2	0.016 (3)	0.025 (3)	0.020 (3)	−0.002 (2)	0.006 (2)	0.006 (2)
N3	0.016 (3)	0.025 (3)	0.021 (3)	−0.002 (2)	0.007 (2)	0.001 (2)
N4	0.020 (3)	0.018 (3)	0.018 (3)	−0.001 (2)	0.009 (2)	−0.002 (2)
N5	0.017 (3)	0.017 (3)	0.020 (3)	−0.001 (2)	0.009 (2)	−0.004 (2)
N6	0.017 (3)	0.021 (3)	0.016 (3)	0.000 (2)	0.005 (2)	0.000 (2)
C1	0.026 (4)	0.026 (4)	0.030 (4)	0.001 (3)	0.007 (3)	0.001 (3)
C2	0.025 (4)	0.030 (4)	0.021 (3)	−0.002 (3)	0.006 (3)	−0.001 (3)
C3	0.025 (4)	0.028 (4)	0.019 (3)	−0.001 (3)	0.006 (3)	0.002 (3)
C4	0.029 (4)	0.033 (4)	0.024 (4)	0.002 (3)	0.015 (3)	0.004 (3)
C5	0.031 (4)	0.023 (4)	0.037 (4)	0.003 (3)	0.021 (4)	0.005 (3)
C6	0.034 (4)	0.022 (4)	0.041 (5)	−0.004 (3)	0.023 (4)	−0.002 (3)
C7	0.030 (4)	0.030 (4)	0.023 (4)	−0.005 (3)	0.009 (3)	−0.008 (3)
C8	0.019 (3)	0.027 (4)	0.021 (3)	−0.002 (3)	0.010 (3)	0.003 (3)
C9	0.025 (3)	0.022 (3)	0.011 (3)	−0.005 (3)	0.002 (3)	0.003 (3)
C10	0.025 (4)	0.026 (4)	0.015 (3)	0.002 (3)	0.006 (3)	0.003 (3)
C11	0.018 (3)	0.024 (4)	0.019 (3)	−0.004 (3)	0.005 (3)	0.004 (3)
C12	0.022 (4)	0.037 (4)	0.019 (3)	0.001 (3)	0.007 (3)	−0.003 (3)
C13	0.025 (4)	0.027 (4)	0.034 (4)	0.003 (3)	0.012 (3)	0.001 (3)
C14	0.022 (4)	0.031 (4)	0.032 (4)	0.001 (3)	0.010 (3)	0.004 (3)
C15	0.024 (4)	0.029 (4)	0.025 (4)	0.001 (3)	0.010 (3)	0.005 (3)
C16	0.022 (4)	0.032 (4)	0.025 (4)	−0.001 (3)	0.006 (3)	0.009 (3)
C17	0.026 (4)	0.038 (5)	0.021 (4)	−0.002 (3)	0.007 (3)	0.006 (3)
C18	0.027 (4)	0.024 (4)	0.021 (3)	−0.002 (3)	0.004 (3)	−0.005 (3)
C19	0.033 (4)	0.020 (4)	0.022 (3)	−0.002 (3)	0.010 (3)	0.000 (3)
C20	0.035 (4)	0.032 (4)	0.026 (4)	−0.008 (3)	0.017 (4)	−0.007 (3)
C21	0.025 (4)	0.029 (4)	0.025 (4)	−0.009 (3)	0.012 (3)	−0.011 (3)
C22	0.030 (4)	0.020 (3)	0.029 (4)	0.000 (3)	0.015 (3)	−0.004 (3)
C23	0.023 (4)	0.023 (4)	0.034 (4)	0.002 (3)	0.013 (3)	−0.002 (3)
C24	0.022 (3)	0.019 (3)	0.027 (4)	−0.002 (3)	0.011 (3)	−0.004 (3)
C25	0.017 (3)	0.020 (3)	0.017 (3)	0.000 (2)	0.008 (3)	0.000 (3)
C26	0.018 (3)	0.024 (4)	0.017 (3)	0.002 (3)	0.005 (3)	−0.004 (3)
C27	0.017 (3)	0.028 (4)	0.022 (3)	−0.003 (3)	0.011 (3)	−0.006 (3)
C28	0.014 (3)	0.023 (3)	0.016 (3)	0.000 (2)	0.008 (2)	−0.003 (3)
C29	0.023 (3)	0.026 (4)	0.016 (3)	0.000 (3)	0.009 (3)	−0.003 (3)
C30	0.026 (4)	0.021 (4)	0.033 (4)	−0.005 (3)	0.015 (3)	0.003 (3)
C31	0.027 (4)	0.020 (4)	0.025 (4)	−0.006 (3)	0.009 (3)	−0.003 (3)
C32	0.025 (4)	0.026 (4)	0.013 (3)	−0.002 (3)	0.007 (3)	−0.004 (3)
C33	0.023 (3)	0.017 (3)	0.020 (3)	0.001 (3)	0.007 (3)	−0.001 (3)
C34	0.025 (4)	0.021 (3)	0.020 (3)	−0.003 (3)	0.010 (3)	−0.007 (3)
C35	0.083 (10)	0.067 (9)	0.038 (6)	−0.003 (7)	0.016 (6)	0.005 (6)
C36	0.046 (7)	0.062 (9)	0.088 (11)	−0.011 (6)	0.009 (7)	0.005 (8)

Geometric parameters (Å, º)

Re1—C1	1.922 (9)	C9—H9B	0.9900
Re1—C2	1.927 (9)	C10—C11	1.488 (10)
Re1—C3	1.932 (8)	C10—H10A	0.9900
Re1—N1	2.174 (6)	C10—H10B	0.9900
Re1—N2	2.225 (6)	C11—C12	1.393 (11)
Re1—N3	2.167 (6)	C12—C13	1.394 (12)
Re2—C18	1.925 (8)	C12—H12	0.9500
Re2—C19	1.927 (8)	C14—C13	1.367 (12)
Re2—C20	1.936 (8)	C14—C15	1.401 (12)
Re2—N4	2.171 (6)	C14—H14	0.9500
Re2—N5	2.233 (6)	C13—H13	0.9500
Re2—N6	2.171 (6)	C15—H15	0.9500
O1—C1	1.148 (10)	C16—C17	1.534 (11)
O2—C2	1.147 (10)	C16—H16A	0.9900
O3—C3	1.160 (9)	C16—H16B	0.9900
O4—C17	1.401 (10)	C17—H17A	0.9900
O4—H4	0.8400	C17—H17B	0.9900
O5—C18	1.146 (10)	C21—C22	1.379 (12)
O6—C20	1.132 (10)	C21—H21	0.9500
O7—C19	1.150 (10)	C22—C23	1.372 (12)
O8—C34	1.403 (9)	C22—H22	0.9500
O8—H8	0.8400	C23—C24	1.380 (11)
O9—C36	1.380 (14)	C23—H23	0.9500
O9—H9	0.8400	C24—C25	1.397 (10)
O10—C35	1.382 (16)	C24—H24	0.9500
O10—H10	0.8400	C25—C26	1.493 (10)
N1—C4	1.331 (10)	C26—H26A	0.9900
N1—C8	1.366 (10)	C26—H26B	0.9900
N2—C9	1.499 (9)	C27—C28	1.493 (10)
N2—C10	1.510 (10)	C27—H27A	0.9900
N2—C16	1.519 (10)	C27—H27B	0.9900
N3—C11	1.345 (9)	C28—C29	1.392 (10)
N3—C15	1.347 (10)	C29—C30	1.389 (11)
N4—C25	1.338 (9)	C29—H29	0.9500
N4—C21	1.361 (10)	C30—C31	1.385 (11)
N5—C27	1.497 (9)	C30—H30	0.9500
N5—C33	1.506 (9)	C31—C32	1.366 (11)
N5—C26	1.518 (9)	C31—H31	0.9500
N6—C32	1.342 (10)	C32—H32	0.9500
N6—C28	1.354 (9)	C33—C34	1.526 (10)
C4—C5	1.388 (12)	C33—H33A	0.9900
C4—H4A	0.9500	C33—H33B	0.9900
C5—C6	1.389 (13)	C34—H34A	0.9900
C5—H5	0.9500	C34—H34B	0.9900
C6—C7	1.391 (12)	C35—H35A	0.9800
C6—H6	0.9500	C35—H35B	0.9800
C7—C8	1.386 (11)	C35—H35C	0.9800
C7—H7	0.9500	C36—H36A	0.9800
C8—C9	1.492 (10)	C36—H36B	0.9800
C9—H9A	0.9900	C36—H36C	0.9800
C1—Re1—C2	89.8 (4)	C11—C12—H12	121.1
C1—Re1—C3	87.3 (4)	C13—C12—H12	121.1
C2—Re1—C3	88.0 (3)	C13—C14—C15	118.4 (8)
C1—Re1—N3	96.7 (3)	C13—C14—H14	120.8
C2—Re1—N3	170.3 (3)	C15—C14—H14	120.8
C3—Re1—N3	99.5 (3)	C14—C13—C12	120.2 (8)
C1—Re1—N1	172.4 (3)	C14—C13—H13	119.9
C2—Re1—N1	96.2 (3)	C12—C13—H13	119.9
C3—Re1—N1	97.6 (3)	N3—C15—C14	122.5 (8)
N3—Re1—N1	76.9 (2)	N3—C15—H15	118.8
C1—Re1—N2	95.9 (3)	C14—C15—H15	118.8
C2—Re1—N2	94.6 (3)	N2—C16—C17	117.2 (7)
C3—Re1—N2	175.9 (3)	N2—C16—H16A	108.0
N3—Re1—N2	77.6 (2)	C17—C16—H16A	108.0
N1—Re1—N2	78.9 (2)	N2—C16—H16B	108.0
C18—Re2—C19	86.4 (3)	C17—C16—H16B	108.0
C18—Re2—C20	89.2 (4)	H16A—C16—H16B	107.2
C19—Re2—C20	87.5 (3)	O4—C17—C16	114.7 (7)
C18—Re2—N4	173.3 (3)	O4—C17—H17A	108.6
C19—Re2—N4	98.5 (3)	C16—C17—H17A	108.6
C20—Re2—N4	95.7 (3)	O4—C17—H17B	108.6
C18—Re2—N6	95.5 (3)	C16—C17—H17B	108.6
C19—Re2—N6	97.3 (3)	H17A—C17—H17B	107.6
C20—Re2—N6	173.5 (3)	O5—C18—Re2	178.3 (8)
N4—Re2—N6	79.3 (2)	O7—C19—Re2	177.2 (8)
C18—Re2—N5	96.5 (3)	O6—C20—Re2	178.6 (9)
C19—Re2—N5	174.7 (3)	N4—C21—C22	122.1 (7)
C20—Re2—N5	97.0 (3)	N4—C21—H21	118.9
N4—Re2—N5	78.3 (2)	C22—C21—H21	118.9
N6—Re2—N5	78.1 (2)	C23—C22—C21	119.9 (7)
C17—O4—H4	109.5	C23—C22—H22	120.1
C34—O8—H8	109.5	C21—C22—H22	120.1
C36—O9—H9	109.5	C22—C23—C24	119.1 (8)
C35—O10—H10	109.5	C22—C23—H23	120.5
C4—N1—C8	118.0 (7)	C24—C23—H23	120.5
C4—N1—Re1	125.9 (5)	C23—C24—C25	118.3 (7)
C8—N1—Re1	114.7 (5)	C23—C24—H24	120.8
C9—N2—C10	109.3 (6)	C25—C24—H24	120.8
C9—N2—C16	110.4 (6)	N4—C25—C24	123.2 (7)
C10—N2—C16	109.6 (6)	N4—C25—C26	117.0 (6)
C9—N2—Re1	108.1 (4)	C24—C25—C26	119.7 (6)
C10—N2—Re1	107.1 (4)	C25—C26—N5	113.2 (6)
C16—N2—Re1	112.2 (5)	C25—C26—H26A	108.9
C11—N3—C15	118.2 (7)	N5—C26—H26A	108.9
C11—N3—Re1	116.2 (5)	C25—C26—H26B	108.9
C15—N3—Re1	124.4 (5)	N5—C26—H26B	108.9
C25—N4—C21	117.4 (7)	H26A—C26—H26B	107.7
C25—N4—Re2	116.2 (5)	C28—C27—N5	113.0 (6)
C21—N4—Re2	125.9 (5)	C28—C27—H27A	109.0
C27—N5—C33	109.2 (5)	N5—C27—H27A	109.0
C27—N5—C26	110.4 (6)	C28—C27—H27B	109.0
C33—N5—C26	108.0 (5)	N5—C27—H27B	109.0
C27—N5—Re2	107.3 (4)	H27A—C27—H27B	107.8
C33—N5—Re2	114.3 (4)	N6—C28—C29	122.3 (7)
C26—N5—Re2	107.7 (4)	N6—C28—C27	115.7 (6)
C32—N6—C28	118.1 (6)	C29—C28—C27	121.9 (6)
C32—N6—Re2	125.5 (5)	C30—C29—C28	118.0 (7)
C28—N6—Re2	115.7 (5)	C30—C29—H29	121.0
O1—C1—Re1	179.1 (8)	C28—C29—H29	121.0
O2—C2—Re1	178.1 (8)	C31—C30—C29	119.7 (7)
O3—C3—Re1	178.8 (8)	C31—C30—H30	120.2
N1—C4—C5	123.6 (8)	C29—C30—H30	120.2
N1—C4—H4A	118.2	C32—C31—C30	118.7 (7)
C5—C4—H4A	118.2	C32—C31—H31	120.6
C4—C5—C6	118.0 (8)	C30—C31—H31	120.6
C4—C5—H5	121.0	N6—C32—C31	123.2 (7)
C6—C5—H5	121.0	N6—C32—H32	118.4
C5—C6—C7	119.6 (8)	C31—C32—H32	118.4
C5—C6—H6	120.2	N5—C33—C34	114.7 (6)
C7—C6—H6	120.2	N5—C33—H33A	108.6
C8—C7—C6	118.6 (8)	C34—C33—H33A	108.6
C8—C7—H7	120.7	N5—C33—H33B	108.6
C6—C7—H7	120.7	C34—C33—H33B	108.6
N1—C8—C7	122.2 (7)	H33A—C33—H33B	107.6
N1—C8—C9	116.7 (7)	O8—C34—C33	109.7 (6)
C7—C8—C9	121.1 (7)	O8—C34—H34A	109.7
C8—C9—N2	113.5 (6)	C33—C34—H34A	109.7
C8—C9—H9A	108.9	O8—C34—H34B	109.7
N2—C9—H9A	108.9	C33—C34—H34B	109.7
C8—C9—H9B	108.9	H34A—C34—H34B	108.2
N2—C9—H9B	108.9	O10—C35—H35A	109.5
H9A—C9—H9B	107.7	O10—C35—H35B	109.5
C11—C10—N2	111.9 (6)	H35A—C35—H35B	109.5
C11—C10—H10A	109.2	O10—C35—H35C	109.5
N2—C10—H10A	109.2	H35A—C35—H35C	109.5
C11—C10—H10B	109.2	H35B—C35—H35C	109.5
N2—C10—H10B	109.2	O9—C36—H36A	109.5
H10A—C10—H10B	107.9	O9—C36—H36B	109.5
N3—C11—C12	122.8 (7)	H36A—C36—H36B	109.5
N3—C11—C10	115.9 (7)	O9—C36—H36C	109.5
C12—C11—C10	121.2 (7)	H36A—C36—H36C	109.5
C11—C12—C13	117.9 (7)	H36B—C36—H36C	109.5
C2—Re1—N1—C4	102.0 (7)	C6—C7—C8—N1	0.7 (12)
C3—Re1—N1—C4	13.2 (7)	C6—C7—C8—C9	177.9 (7)
N3—Re1—N1—C4	−84.9 (6)	N1—C8—C9—N2	−31.2 (10)
N2—Re1—N1—C4	−164.5 (7)	C7—C8—C9—N2	151.5 (7)
C2—Re1—N1—C8	−92.4 (6)	C10—N2—C9—C8	−86.8 (7)
C3—Re1—N1—C8	178.8 (6)	C16—N2—C9—C8	152.5 (7)
N3—Re1—N1—C8	80.8 (5)	Re1—N2—C9—C8	29.5 (7)
N2—Re1—N1—C8	1.1 (5)	C9—N2—C10—C11	80.9 (7)
C1—Re1—N2—C9	169.2 (5)	C16—N2—C10—C11	−157.9 (6)
C2—Re1—N2—C9	78.9 (5)	Re1—N2—C10—C11	−36.0 (7)
N3—Re1—N2—C9	−95.3 (5)	C15—N3—C11—C12	1.6 (11)
N1—Re1—N2—C9	−16.5 (5)	Re1—N3—C11—C12	169.2 (6)
C1—Re1—N2—C10	−73.1 (5)	C15—N3—C11—C10	179.5 (7)
C2—Re1—N2—C10	−163.3 (5)	Re1—N3—C11—C10	−12.9 (8)
N3—Re1—N2—C10	22.5 (5)	N2—C10—C11—N3	33.8 (9)
N1—Re1—N2—C10	101.3 (5)	N2—C10—C11—C12	−148.3 (7)
C1—Re1—N2—C16	47.2 (5)	N3—C11—C12—C13	−1.9 (11)
C2—Re1—N2—C16	−43.1 (5)	C10—C11—C12—C13	−179.6 (7)
N3—Re1—N2—C16	142.7 (5)	C15—C14—C13—C12	1.6 (12)
N1—Re1—N2—C16	−138.5 (5)	C11—C12—C13—C14	0.2 (12)
C1—Re1—N3—C11	88.4 (6)	C11—N3—C15—C14	0.3 (11)
C3—Re1—N3—C11	176.8 (5)	Re1—N3—C15—C14	−166.2 (6)
N1—Re1—N3—C11	−87.5 (5)	C13—C14—C15—N3	−1.9 (12)
N2—Re1—N3—C11	−6.2 (5)	C9—N2—C16—C17	71.1 (8)
C1—Re1—N3—C15	−104.8 (7)	C10—N2—C16—C17	−49.5 (8)
C3—Re1—N3—C15	−16.4 (7)	Re1—N2—C16—C17	−168.3 (5)
N1—Re1—N3—C15	79.2 (6)	N2—C16—C17—O4	−56.1 (10)
N2—Re1—N3—C15	160.6 (6)	C25—N4—C21—C22	0.8 (11)
C19—Re2—N4—C25	−179.7 (5)	Re2—N4—C21—C22	−171.0 (6)
C20—Re2—N4—C25	92.0 (5)	N4—C21—C22—C23	0.0 (12)
N6—Re2—N4—C25	−83.9 (5)	C21—C22—C23—C24	−0.2 (12)
N5—Re2—N4—C25	−4.0 (5)	C22—C23—C24—C25	−0.5 (11)
C19—Re2—N4—C21	−7.8 (6)	C21—N4—C25—C24	−1.6 (10)
C20—Re2—N4—C21	−96.1 (6)	Re2—N4—C25—C24	171.1 (6)
N6—Re2—N4—C21	88.0 (6)	C21—N4—C25—C26	175.4 (6)
N5—Re2—N4—C21	167.9 (6)	Re2—N4—C25—C26	−11.9 (8)
C20—Re2—N5—C27	164.5 (5)	C23—C24—C25—N4	1.4 (11)
N4—Re2—N5—C27	−101.1 (5)	C23—C24—C25—C26	−175.5 (7)
N6—Re2—N5—C27	−19.8 (4)	N4—C25—C26—N5	28.5 (9)
C18—Re2—N5—C33	−46.7 (5)	C24—C25—C26—N5	−154.4 (6)
C20—Re2—N5—C33	43.3 (5)	C27—N5—C26—C25	87.6 (7)
N4—Re2—N5—C33	137.7 (5)	C33—N5—C26—C25	−153.1 (6)
N6—Re2—N5—C33	−141.0 (5)	Re2—N5—C26—C25	−29.2 (7)
C18—Re2—N5—C26	−166.7 (5)	C33—N5—C27—C28	158.2 (6)
C20—Re2—N5—C26	−76.7 (5)	C26—N5—C27—C28	−83.3 (7)
N4—Re2—N5—C26	17.7 (4)	Re2—N5—C27—C28	33.8 (7)
N6—Re2—N5—C26	99.0 (5)	C32—N6—C28—C29	1.3 (10)
C18—Re2—N6—C32	98.1 (6)	Re2—N6—C28—C29	−169.0 (5)
C19—Re2—N6—C32	11.1 (7)	C32—N6—C28—C27	−174.4 (6)
N4—Re2—N6—C32	−86.2 (6)	Re2—N6—C28—C27	15.2 (8)
N5—Re2—N6—C32	−166.4 (6)	N5—C27—C28—N6	−34.0 (9)
C18—Re2—N6—C28	−92.4 (5)	N5—C27—C28—C29	150.2 (7)
C19—Re2—N6—C28	−179.4 (5)	N6—C28—C29—C30	−1.2 (11)
N4—Re2—N6—C28	83.3 (5)	C27—C28—C29—C30	174.3 (7)
N5—Re2—N6—C28	3.2 (5)	C28—C29—C30—C31	0.3 (11)
C8—N1—C4—C5	−0.4 (11)	C29—C30—C31—C32	0.4 (12)
Re1—N1—C4—C5	164.8 (6)	C28—N6—C32—C31	−0.6 (11)
N1—C4—C5—C6	0.6 (12)	Re2—N6—C32—C31	168.7 (6)
C4—C5—C6—C7	−0.2 (12)	C30—C31—C32—N6	−0.2 (12)
C5—C6—C7—C8	−0.5 (12)	C27—N5—C33—C34	56.0 (8)
C4—N1—C8—C7	−0.3 (11)	C26—N5—C33—C34	−64.0 (8)
Re1—N1—C8—C7	−167.1 (6)	Re2—N5—C33—C34	176.2 (5)
C4—N1—C8—C9	−177.6 (7)	N5—C33—C34—O8	165.9 (6)
Re1—N1—C8—C9	15.6 (8)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···Br1	0.84	2.39	3.213 (7)	167
O8—H8···Br2	0.84	2.51	3.282 (6)	153
O9—H9···Br1	0.84	2.56	3.390 (8)	168
O10—H10···O9	0.84	2.27	3.059 (16)	156
C9—H9A···O4	0.99	2.57	2.969 (10)	104
C24—H24···O4^i	0.95	2.37	3.299 (8)	167
C30—H30···O7^ii	0.95	2.47	3.225 (11)	137
C17—H17A···Br2^iii	0.99	2.87	3.788 (10)	155
C22—H22···Br1^iv	0.95	2.79	3.552 (7)	138
C26—H26B···Br1^i	0.99	2.82	3.798 (6)	167
C27—H27A···Br1^i	0.99	2.83	3.798 (8)	166
C34—H34A···Br1^v	0.99	2.90	3.724 (9)	141

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