Towards direct correlations between spin-crossover and structural features in iron(II) complexes

The [Fe(PM-BiA)₂(NCS)₂] complex, where PM is N-2-pyridylmethylene and BiA is 4-aminobiphenyl, crystallizes in two polymorphs. The two phases, denoted (I) and (II), undergo a spin-crossover when the sample is cooled and present distinct spin-transition features as (I) shows a very abrupt spin transition, while (II) exhibits a gradual transition. The two forms of the complex are used to investigate the correlations that exist between the spin-transition features and structural features. This article presents the crystal structures of polymorph (II) at room temperature (high spin) and at 120 K (low spin), including a comparison with those of polymorph (I). This study reveals that the packing, in a first approximation, is similar in both forms. In order to look at the crystal structures in more detail, a new angular parameter, denoted θ_NCS, as well as a particular type of intermolecular hydrogen-bond interaction, which involves the S atoms of the NCS ligands, are investigated. Interestingly, this angle and this intermolecular interaction can be directly connected to the cooperativity of the spin transition. Such a result is extended to all the SCO iron(II) complexes belonging to the same family of the general formula [Fe(PM-L)₂(NCS)₂].

Computing details

For both compounds, program(s) used to solve structure: SIR 97; program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP 32; software used to prepare material for publication: SHELXL97.

Figures

(biamono)

Crystal data

C38H28FeN6S2	F(000) = 1424
Mr = 688.63	Dx = 1.321 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
a = 17.570 (5) Å	Cell parameters from 11821 reflections
b = 12.602 (5) Å	θ = 1.0–27.5°
c = 17.358 (5) Å	µ = 0.59 mm^−1
β = 115.684 (5)°	T = 293 K
V = 3464 (2) Å^3	Pin, black
Z = 4	0.15 × 0.1 × 0.1 mm

Data collection

NONIUS Kappa CCD diffractometer	3906 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.041
Graphite monochromator	θmax = 25.0°, θmin = 1.3°
Detector resolution: 512 pixels mm^-1	h = −20→20
profile data from ϕ and ω scans	k = −14→14
23166 measured reflections	l = −20→20
6118 independent 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)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.198	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ^2(Fo^2) + (0.1242P)^2] where P = (Fo^2 + 2Fc^2)/3
6118 reflections	(Δ/σ)max < 0.001
424 parameters	Δρmax = 0.66 e Å^−3
0 restraints	Δρmin = −0.88 e Å^−3

Special details

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
Fe1	0.25924 (3)	0.19783 (4)	0.32624 (3)	0.0664 (2)
S1A	0.04611 (8)	0.15622 (10)	0.42159 (7)	0.0918 (4)
S1B	0.45240 (8)	0.38646 (10)	0.57041 (7)	0.1002 (4)
N2B	0.16745 (19)	0.1896 (2)	0.18785 (17)	0.0668 (8)
N1B	0.21054 (19)	0.3586 (2)	0.29337 (17)	0.0666 (7)
N2A	0.34728 (19)	0.2249 (2)	0.26505 (17)	0.0665 (7)
N3B	0.3483 (2)	0.2488 (3)	0.44490 (19)	0.0823 (9)
N1A	0.3108 (2)	0.0440 (2)	0.32208 (19)	0.0830 (10)
N3A	0.1732 (3)	0.1413 (3)	0.3679 (2)	0.0976 (11)
C1A	0.2944 (4)	−0.0475 (4)	0.3528 (3)	0.1137 (17)
H1A	0.2565	−0.0473	0.3771	0.136*
C2A	0.3334 (6)	−0.1421 (5)	0.3488 (4)	0.154 (3)
H2A	0.3215	−0.2043	0.3702	0.184*
C3A	0.3899 (7)	−0.1436 (5)	0.3129 (6)	0.166 (3)
H3A	0.4166	−0.2066	0.3108	0.199*
C4A	0.4067 (4)	−0.0518 (4)	0.2803 (4)	0.133 (2)
H4A	0.4442	−0.0512	0.2556	0.160*
C5A	0.3655 (3)	0.0401 (3)	0.2858 (3)	0.0892 (12)
C6A	0.3800 (3)	0.1402 (3)	0.2526 (2)	0.0822 (11)
H6A	0.4129	0.1423	0.2226	0.099*
C7A	0.3573 (2)	0.3221 (3)	0.2281 (2)	0.0643 (9)
C8A	0.3384 (3)	0.3274 (3)	0.1418 (2)	0.0752 (10)
H8A	0.3220	0.2666	0.1082	0.090*
C9A	0.3440 (3)	0.4227 (3)	0.1063 (2)	0.0830 (11)
H9A	0.3323	0.4254	0.0487	0.100*
C10A	0.3668 (2)	0.5154 (3)	0.1546 (2)	0.0723 (10)
C11A	0.3846 (2)	0.5085 (3)	0.2411 (2)	0.0741 (10)
H11A	0.3999	0.5693	0.2747	0.089*
C12A	0.3799 (2)	0.4125 (3)	0.2776 (2)	0.0706 (9)
H12A	0.3920	0.4090	0.3353	0.085*
C13A	0.3754 (3)	0.6187 (4)	0.1173 (3)	0.0920 (13)
C14A	0.4255 (4)	0.6268 (5)	0.0740 (3)	0.134 (2)
H14A	0.4519	0.5679	0.0641	0.161*
C15A	0.4345 (5)	0.7324 (9)	0.0447 (5)	0.186 (5)
H15A	0.4712	0.7415	0.0196	0.223*
C16A	0.3913 (9)	0.8188 (7)	0.0527 (7)	0.200 (6)
H16A	0.3926	0.8840	0.0283	0.240*
C17A	0.3506 (8)	0.8047 (6)	0.0943 (6)	0.197 (5)
H17A	0.3246	0.8643	0.1038	0.236*
C18A	0.3390 (5)	0.7106 (5)	0.1285 (4)	0.141 (2)
H18A	0.3067	0.7093	0.1591	0.170*
C19A	0.1201 (3)	0.1479 (3)	0.3906 (2)	0.0736 (10)
C1B	0.2313 (3)	0.4428 (3)	0.3460 (2)	0.0768 (10)
H1B	0.2651	0.4323	0.4039	0.092*
C2B	0.2048 (3)	0.5427 (3)	0.3178 (3)	0.0880 (12)
H2B	0.2203	0.5990	0.3562	0.106*
C3B	0.1556 (3)	0.5601 (3)	0.2332 (3)	0.0979 (13)
H3B	0.1374	0.6283	0.2131	0.117*
C4B	0.1332 (3)	0.4740 (3)	0.1773 (3)	0.0868 (12)
H4B	0.0996	0.4835	0.1192	0.104*
C5B	0.1613 (2)	0.3752 (3)	0.2096 (2)	0.0682 (9)
C6B	0.1396 (2)	0.2805 (3)	0.1557 (2)	0.0718 (10)
H6B	0.1051	0.2866	0.0975	0.086*
C7B	0.1483 (2)	0.1009 (3)	0.1324 (2)	0.0649 (9)
C8B	0.1534 (3)	0.1057 (3)	0.0551 (2)	0.0748 (10)
H8B	0.1692	0.1686	0.0380	0.090*
C9B	0.1351 (3)	0.0177 (3)	0.0036 (2)	0.0788 (10)
H9B	0.1394	0.0224	−0.0479	0.095*
C10B	0.1105 (2)	−0.0781 (3)	0.0253 (2)	0.0706 (10)
C11B	0.1050 (3)	−0.0813 (3)	0.1031 (2)	0.0794 (11)
H11B	0.0879	−0.1437	0.1195	0.095*
C12B	0.1244 (3)	0.0061 (3)	0.1562 (2)	0.0775 (10)
H12B	0.1214	0.0013	0.2083	0.093*
C13B	0.0936 (3)	−0.1728 (3)	−0.0308 (2)	0.0741 (10)
C14B	0.0596 (3)	−0.1642 (4)	−0.1190 (2)	0.0831 (11)
H14B	0.0448	−0.0977	−0.1444	0.100*
C15B	0.0474 (3)	−0.2530 (4)	−0.1700 (3)	0.0936 (13)
H15B	0.0250	−0.2453	−0.2291	0.112*
C16B	0.0679 (3)	−0.3525 (4)	−0.1344 (3)	0.1029 (15)
H16B	0.0603	−0.4117	−0.1689	0.124*
C17B	0.0992 (4)	−0.3634 (4)	−0.0487 (3)	0.1133 (17)
H17B	0.1115	−0.4307	−0.0244	0.136*
C18B	0.1131 (3)	−0.2750 (3)	0.0033 (3)	0.0962 (13)
H18B	0.1360	−0.2840	0.0623	0.115*
C19B	0.3918 (3)	0.3055 (3)	0.4982 (2)	0.0728 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Fe1	0.0845 (4)	0.0599 (4)	0.0547 (3)	−0.0033 (2)	0.0301 (3)	0.0016 (2)
S1A	0.0986 (8)	0.0980 (8)	0.0816 (7)	−0.0103 (6)	0.0417 (6)	−0.0098 (6)
S1B	0.1179 (10)	0.0862 (8)	0.0926 (8)	−0.0207 (7)	0.0419 (7)	−0.0232 (6)
N2B	0.0726 (19)	0.0634 (19)	0.0618 (16)	−0.0051 (15)	0.0267 (14)	0.0009 (14)
N1B	0.0762 (19)	0.0655 (19)	0.0609 (17)	0.0003 (15)	0.0325 (14)	−0.0034 (14)
N2A	0.0780 (19)	0.0601 (18)	0.0592 (16)	0.0009 (15)	0.0278 (14)	−0.0033 (13)
N3B	0.099 (2)	0.086 (2)	0.0568 (18)	−0.0049 (19)	0.0287 (16)	0.0014 (16)
N1A	0.111 (3)	0.0570 (19)	0.0672 (18)	−0.0049 (18)	0.0253 (17)	0.0051 (15)
N3A	0.111 (3)	0.108 (3)	0.083 (2)	−0.016 (2)	0.051 (2)	0.008 (2)
C1A	0.156 (5)	0.076 (3)	0.086 (3)	−0.012 (3)	0.032 (3)	0.013 (2)
C2A	0.233 (9)	0.062 (4)	0.131 (5)	−0.002 (4)	0.047 (5)	0.019 (3)
C3A	0.230 (9)	0.077 (5)	0.172 (7)	0.029 (5)	0.070 (6)	0.000 (4)
C4A	0.171 (6)	0.075 (4)	0.149 (5)	0.024 (3)	0.065 (4)	−0.011 (3)
C5A	0.108 (3)	0.067 (3)	0.080 (2)	0.010 (2)	0.028 (2)	−0.007 (2)
C6A	0.097 (3)	0.075 (3)	0.081 (3)	0.008 (2)	0.044 (2)	−0.006 (2)
C7A	0.067 (2)	0.066 (2)	0.062 (2)	−0.0035 (17)	0.0305 (16)	−0.0031 (16)
C8A	0.097 (3)	0.073 (2)	0.062 (2)	−0.014 (2)	0.0393 (19)	−0.0120 (17)
C9A	0.097 (3)	0.093 (3)	0.062 (2)	−0.019 (2)	0.0374 (19)	−0.003 (2)
C10A	0.068 (2)	0.074 (2)	0.069 (2)	−0.0145 (19)	0.0252 (17)	−0.0004 (18)
C11A	0.079 (2)	0.070 (2)	0.068 (2)	−0.0169 (19)	0.0261 (18)	−0.0106 (18)
C12A	0.075 (2)	0.076 (2)	0.0574 (18)	−0.0049 (19)	0.0246 (16)	−0.0049 (17)
C13A	0.090 (3)	0.093 (3)	0.076 (2)	−0.034 (3)	0.020 (2)	0.006 (2)
C14A	0.111 (4)	0.167 (6)	0.116 (4)	−0.038 (4)	0.041 (3)	0.032 (4)
C15A	0.132 (6)	0.252 (10)	0.127 (5)	−0.104 (7)	0.011 (4)	0.076 (7)
C16A	0.253 (13)	0.115 (6)	0.135 (7)	−0.079 (7)	−0.006 (7)	0.042 (5)
C17A	0.293 (14)	0.085 (5)	0.137 (7)	−0.044 (6)	0.022 (7)	0.030 (4)
C18A	0.177 (6)	0.090 (4)	0.132 (5)	−0.016 (4)	0.043 (4)	0.011 (3)
C19A	0.092 (3)	0.066 (2)	0.056 (2)	−0.018 (2)	0.025 (2)	−0.0024 (16)
C1B	0.089 (3)	0.068 (2)	0.073 (2)	0.010 (2)	0.035 (2)	−0.0051 (19)
C2B	0.098 (3)	0.071 (3)	0.093 (3)	0.011 (2)	0.040 (2)	−0.014 (2)
C3B	0.105 (3)	0.066 (3)	0.115 (4)	0.019 (2)	0.041 (3)	0.010 (2)
C4B	0.096 (3)	0.073 (3)	0.074 (2)	0.010 (2)	0.020 (2)	0.004 (2)
C5B	0.072 (2)	0.066 (2)	0.066 (2)	0.0014 (18)	0.0283 (17)	0.0026 (17)
C6B	0.074 (2)	0.075 (3)	0.0569 (19)	−0.0023 (19)	0.0190 (16)	−0.0013 (18)
C7B	0.073 (2)	0.060 (2)	0.0555 (18)	−0.0056 (17)	0.0226 (16)	−0.0035 (15)
C8B	0.094 (3)	0.062 (2)	0.071 (2)	−0.0136 (19)	0.0383 (19)	0.0019 (17)
C9B	0.103 (3)	0.073 (3)	0.067 (2)	−0.015 (2)	0.043 (2)	−0.0045 (18)
C10B	0.075 (2)	0.067 (2)	0.070 (2)	−0.0097 (18)	0.0314 (18)	−0.0021 (17)
C11B	0.101 (3)	0.067 (2)	0.074 (2)	−0.019 (2)	0.042 (2)	−0.0019 (18)
C12B	0.100 (3)	0.076 (3)	0.062 (2)	−0.015 (2)	0.0406 (19)	0.0001 (18)
C13B	0.082 (3)	0.068 (2)	0.075 (2)	−0.0137 (19)	0.0366 (19)	−0.0090 (18)
C14B	0.087 (3)	0.084 (3)	0.077 (3)	−0.012 (2)	0.034 (2)	−0.003 (2)
C15B	0.103 (3)	0.100 (3)	0.079 (3)	−0.018 (3)	0.041 (2)	−0.024 (2)
C16B	0.123 (4)	0.080 (3)	0.110 (4)	−0.019 (3)	0.054 (3)	−0.030 (3)
C17B	0.158 (5)	0.069 (3)	0.113 (4)	−0.010 (3)	0.059 (4)	−0.014 (3)
C18B	0.129 (4)	0.075 (3)	0.087 (3)	−0.006 (3)	0.049 (3)	−0.002 (2)
C19B	0.092 (3)	0.071 (2)	0.058 (2)	0.004 (2)	0.034 (2)	0.0063 (18)

Geometric parameters (Å, º)

Fe1—N3A	2.066 (4)	C10A—C11A	1.398 (5)
Fe1—N3B	2.076 (3)	C10A—C13A	1.490 (6)
Fe1—N1A	2.153 (4)	C11A—C12A	1.384 (5)
Fe1—N1B	2.177 (3)	C13A—C18A	1.377 (8)
Fe1—N2B	2.241 (3)	C13A—C14A	1.387 (7)
Fe1—N2A	2.250 (3)	C14A—C15A	1.457 (10)
S1A—C19A	1.612 (5)	C15A—C16A	1.368 (15)
S1B—C19B	1.609 (4)	C16A—C17A	1.229 (17)
N2B—C6B	1.276 (5)	C17A—C18A	1.380 (9)
N2B—C7B	1.417 (4)	C1B—C2B	1.357 (5)
N1B—C1B	1.343 (4)	C2B—C3B	1.361 (6)
N1B—C5B	1.347 (4)	C3B—C4B	1.395 (6)
N2A—C6A	1.275 (5)	C4B—C5B	1.366 (5)
N2A—C7A	1.429 (4)	C5B—C6B	1.462 (5)
N3B—C19B	1.157 (5)	C7B—C8B	1.384 (5)
N1A—C1A	1.354 (6)	C7B—C12B	1.389 (5)
N1A—C5A	1.360 (6)	C8B—C9B	1.372 (5)
N3A—C19A	1.161 (5)	C9B—C10B	1.389 (5)
C1A—C2A	1.392 (9)	C10B—C11B	1.394 (5)
C2A—C3A	1.381 (11)	C10B—C13B	1.486 (5)
C3A—C4A	1.374 (10)	C11B—C12B	1.380 (5)
C4A—C5A	1.390 (7)	C13B—C14B	1.386 (5)
C5A—C6A	1.454 (6)	C13B—C18B	1.397 (6)
C7A—C12A	1.378 (5)	C14B—C15B	1.385 (6)
C7A—C8A	1.388 (5)	C15B—C16B	1.375 (7)
C8A—C9A	1.373 (5)	C16B—C17B	1.351 (6)
C9A—C10A	1.392 (5)	C17B—C18B	1.387 (6)
N3A—Fe1—N3B	96.35 (14)	C9A—C10A—C11A	117.8 (3)
N3A—Fe1—N1A	94.78 (16)	C9A—C10A—C13A	121.9 (3)
N3B—Fe1—N1A	99.47 (13)	C11A—C10A—C13A	120.3 (3)
N3A—Fe1—N1B	98.55 (15)	C12A—C11A—C10A	121.1 (3)
N3B—Fe1—N1B	90.79 (13)	C7A—C12A—C11A	119.7 (3)
N1A—Fe1—N1B	162.17 (12)	C18A—C13A—C14A	117.2 (5)
N3A—Fe1—N2B	93.64 (13)	C18A—C13A—C10A	122.2 (5)
N3B—Fe1—N2B	163.85 (12)	C14A—C13A—C10A	120.5 (5)
N1A—Fe1—N2B	92.29 (11)	C13A—C14A—C15A	116.5 (7)
N1B—Fe1—N2B	75.16 (10)	C16A—C15A—C14A	122.8 (9)
N3A—Fe1—N2A	167.21 (13)	C17A—C16A—C15A	115.7 (9)
N3B—Fe1—N2A	92.57 (12)	C16A—C17A—C18A	127.4 (12)
N1A—Fe1—N2A	74.66 (13)	C13A—C18A—C17A	119.9 (8)
N1B—Fe1—N2A	90.45 (11)	N3A—C19A—S1A	179.5 (4)
N2B—Fe1—N2A	79.84 (11)	N1B—C1B—C2B	122.6 (3)
C6B—N2B—C7B	118.6 (3)	C1B—C2B—C3B	119.8 (4)
C6B—N2B—Fe1	112.8 (2)	C2B—C3B—C4B	118.7 (4)
C7B—N2B—Fe1	127.8 (2)	C5B—C4B—C3B	118.7 (4)
C1B—N1B—C5B	118.0 (3)	N1B—C5B—C4B	122.2 (3)
C1B—N1B—Fe1	126.7 (2)	N1B—C5B—C6B	115.6 (3)
C5B—N1B—Fe1	115.0 (2)	C4B—C5B—C6B	122.2 (3)
C6A—N2A—C7A	119.3 (3)	N2B—C6B—C5B	120.6 (3)
C6A—N2A—Fe1	114.0 (3)	C8B—C7B—C12B	118.8 (3)
C7A—N2A—Fe1	125.8 (2)	C8B—C7B—N2B	121.9 (3)
C19B—N3B—Fe1	159.6 (3)	C12B—C7B—N2B	119.3 (3)
C1A—N1A—C5A	117.7 (4)	C9B—C8B—C7B	120.1 (3)
C1A—N1A—Fe1	126.2 (4)	C8B—C9B—C10B	122.5 (3)
C5A—N1A—Fe1	116.1 (3)	C9B—C10B—C11B	116.6 (3)
C19A—N3A—Fe1	155.6 (4)	C9B—C10B—C13B	121.1 (3)
N1A—C1A—C2A	121.1 (6)	C11B—C10B—C13B	122.2 (3)
C3A—C2A—C1A	120.0 (6)	C12B—C11B—C10B	121.6 (3)
C4A—C3A—C2A	119.9 (7)	C11B—C12B—C7B	120.4 (3)
C3A—C4A—C5A	117.5 (7)	C14B—C13B—C18B	116.7 (4)
N1A—C5A—C4A	123.8 (5)	C14B—C13B—C10B	122.0 (4)
N1A—C5A—C6A	115.6 (4)	C18B—C13B—C10B	121.3 (4)
C4A—C5A—C6A	120.6 (5)	C15B—C14B—C13B	121.1 (4)
N2A—C6A—C5A	119.3 (4)	C16B—C15B—C14B	120.8 (4)
C12A—C7A—C8A	120.2 (3)	C17B—C16B—C15B	119.4 (4)
C12A—C7A—N2A	119.2 (3)	C16B—C17B—C18B	120.5 (5)
C8A—C7A—N2A	120.4 (3)	C17B—C18B—C13B	121.5 (4)
C9A—C8A—C7A	119.7 (3)	N3B—C19B—S1B	178.5 (4)
C8A—C9A—C10A	121.5 (3)

(bia120K2)

Crystal data

C38H28FeN6S2	F(000) = 1424
Mr = 688.63	Dx = 1.389 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
a = 17.362 (5) Å	Cell parameters from 14905 reflections
b = 12.362 (5) Å	θ = 1.0–27.5°
c = 17.050 (5) Å	µ = 0.62 mm^−1
β = 115.833 (5)°	T = 120 K
V = 3293.7 (19) Å^3	Pin, black
Z = 4	0.15 × 0.1 × 0.1 mm

Data collection

BRUCKER-NONIUS Kappa CCD diffractometer	5536 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.053
Graphite monochromator	θmax = 27.5°, θmin = 1.3°
Detector resolution: 512 pixels mm^-1	h = −22→22
profile data from ϕ and ω scans	k = −16→16
29088 measured reflections	l = −22→22
7540 independent 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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.144	H atoms treated by a mixture of independent and constrained refinement
S = 1.20	w = 1/[σ^2(Fo^2) + (0.078P)^2 + 0.0869P] where P = (Fo^2 + 2Fc^2)/3
7540 reflections	(Δ/σ)max = 0.001
424 parameters	Δρmax = 0.68 e Å^−3
0 restraints	Δρmin = −1.00 e Å^−3

Special details

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
Fe1	0.25556 (2)	0.20960 (3)	0.31322 (2)	0.02212 (12)
S1A	0.04588 (4)	0.16746 (5)	0.41723 (4)	0.02846 (17)
S1B	0.44775 (4)	0.36214 (6)	0.57792 (4)	0.03246 (18)
N2B	0.16998 (13)	0.19720 (15)	0.19095 (12)	0.0233 (4)
N1B	0.21424 (13)	0.36016 (16)	0.29432 (12)	0.0225 (4)
N2A	0.34026 (13)	0.23379 (16)	0.26745 (12)	0.0240 (5)
N3B	0.33999 (13)	0.24355 (17)	0.43120 (13)	0.0260 (5)
N1A	0.29952 (13)	0.06185 (16)	0.32269 (12)	0.0275 (5)
N3A	0.17182 (14)	0.17349 (17)	0.35653 (13)	0.0275 (5)
C1A	0.27644 (18)	−0.0255 (2)	0.35434 (16)	0.0350 (6)
H1A	0.2336	−0.0182	0.3744	0.042*
C2A	0.3136 (2)	−0.1262 (2)	0.35847 (19)	0.0479 (8)
H2A	0.2949	−0.1871	0.3795	0.058*
C3A	0.3776 (2)	−0.1376 (2)	0.3320 (2)	0.0530 (9)
H3A	0.4046	−0.2056	0.3362	0.064*
C4A	0.4019 (2)	−0.0484 (2)	0.29915 (19)	0.0457 (8)
H4A	0.4453	−0.0543	0.2796	0.055*
C5A	0.36176 (17)	0.0495 (2)	0.29533 (16)	0.0317 (6)
C6A	0.38092 (17)	0.1488 (2)	0.26218 (16)	0.0311 (6)
H6A	0.4210	0.1512	0.2380	0.037*
C7A	0.35227 (16)	0.3334 (2)	0.23110 (15)	0.0246 (5)
C8A	0.33329 (17)	0.3389 (2)	0.14318 (16)	0.0286 (6)
H8A	0.3156	0.2759	0.1078	0.034*
C9A	0.34045 (17)	0.4374 (2)	0.10729 (17)	0.0305 (6)
H9A	0.3283	0.4410	0.0474	0.037*
C10A	0.36536 (16)	0.5310 (2)	0.15835 (16)	0.0278 (6)
C11A	0.38390 (16)	0.5230 (2)	0.24634 (16)	0.0292 (6)
H11A	0.4007	0.5860	0.2817	0.035*
C12A	0.37839 (16)	0.4252 (2)	0.28336 (15)	0.0268 (6)
H12A	0.3923	0.4209	0.3437	0.032*
C13A	0.37406 (17)	0.6366 (2)	0.12117 (16)	0.0321 (6)
C14A	0.4215 (2)	0.6451 (3)	0.07349 (18)	0.0434 (8)
H14A	0.4463	0.5824	0.0618	0.052*
C15A	0.4327 (2)	0.7462 (3)	0.0427 (2)	0.0568 (10)
H15A	0.4664	0.7517	0.0115	0.068*
C16A	0.3956 (2)	0.8369 (3)	0.0569 (2)	0.0591 (10)
H16A	0.4033	0.9049	0.0354	0.071*
C17A	0.3477 (2)	0.8295 (3)	0.1020 (2)	0.0594 (10)
H17A	0.3209	0.8924	0.1107	0.071*
C18A	0.3375 (2)	0.7306 (2)	0.13553 (19)	0.0434 (7)
H18A	0.3054	0.7271	0.1685	0.052*
C19A	0.11958 (17)	0.17121 (19)	0.38190 (15)	0.0244 (5)
C1B	0.23620 (16)	0.4428 (2)	0.35150 (15)	0.0264 (5)
H1B	0.2725	0.4285	0.4111	0.032*
C2B	0.20819 (16)	0.5470 (2)	0.32719 (16)	0.0290 (6)
H2B	0.2261	0.6033	0.3694	0.035*
C3B	0.15396 (17)	0.5697 (2)	0.24129 (16)	0.0315 (6)
H3B	0.1346	0.6414	0.2235	0.038*
C4B	0.12833 (17)	0.4854 (2)	0.18162 (16)	0.0286 (6)
H4B	0.0902	0.4981	0.1223	0.034*
C5B	0.15911 (16)	0.38275 (19)	0.20980 (15)	0.0243 (5)
C6B	0.13582 (16)	0.28799 (19)	0.15430 (15)	0.0239 (5)
H6B	0.0975	0.2922	0.0942	0.029*
C7B	0.15008 (15)	0.10239 (19)	0.13616 (14)	0.0232 (5)
C8B	0.15848 (16)	0.1047 (2)	0.05907 (15)	0.0268 (6)
H8B	0.1774	0.1688	0.0420	0.032*
C9B	0.13913 (16)	0.0132 (2)	0.00685 (16)	0.0273 (6)
H9B	0.1447	0.0155	−0.0461	0.033*
C10B	0.11173 (15)	−0.08201 (19)	0.03035 (15)	0.0241 (5)
C11B	0.10235 (16)	−0.0821 (2)	0.10783 (15)	0.0274 (6)
H11B	0.0822	−0.1454	0.1245	0.033*
C12B	0.12209 (16)	0.00905 (19)	0.16076 (15)	0.0253 (5)
H12B	0.1164	0.0074	0.2137	0.030*
C13B	0.09505 (16)	−0.1808 (2)	−0.02487 (15)	0.0250 (5)
C14B	0.06206 (16)	−0.1733 (2)	−0.11543 (16)	0.0277 (6)
H14B	0.0477	−0.1043	−0.1426	0.033*
C15B	0.04987 (17)	−0.2653 (2)	−0.16665 (17)	0.0308 (6)
H15B	0.0270	−0.2589	−0.2282	0.037*
C16B	0.07110 (17)	−0.3661 (2)	−0.12785 (17)	0.0325 (6)
H16B	0.0638	−0.4289	−0.1625	0.039*
C17B	0.10299 (18)	−0.3749 (2)	−0.03830 (17)	0.0328 (6)
H17B	0.1167	−0.4441	−0.0115	0.039*
C18B	0.11512 (17)	−0.2834 (2)	0.01255 (17)	0.0295 (6)
H18B	0.1375	−0.2906	0.0740	0.035*
C19B	0.38556 (16)	0.2902 (2)	0.49329 (16)	0.0247 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Fe1	0.0271 (2)	0.0163 (2)	0.0200 (2)	0.00060 (14)	0.00748 (15)	0.00079 (13)
S1A	0.0328 (4)	0.0263 (4)	0.0260 (3)	−0.0036 (3)	0.0125 (3)	−0.0013 (3)
S1B	0.0341 (4)	0.0316 (4)	0.0285 (4)	−0.0042 (3)	0.0108 (3)	−0.0090 (3)
N2B	0.0274 (11)	0.0192 (11)	0.0217 (10)	−0.0009 (9)	0.0091 (9)	−0.0010 (8)
N1B	0.0264 (11)	0.0188 (11)	0.0214 (10)	−0.0002 (8)	0.0097 (9)	−0.0005 (8)
N2A	0.0274 (11)	0.0210 (11)	0.0198 (10)	0.0005 (9)	0.0069 (9)	−0.0004 (8)
N3B	0.0298 (12)	0.0219 (11)	0.0230 (11)	0.0018 (9)	0.0084 (9)	0.0035 (9)
N1A	0.0311 (12)	0.0202 (11)	0.0231 (10)	0.0015 (9)	0.0042 (9)	0.0014 (8)
N3A	0.0316 (12)	0.0252 (11)	0.0227 (11)	−0.0011 (9)	0.0091 (10)	0.0022 (9)
C1A	0.0407 (16)	0.0225 (14)	0.0289 (14)	−0.0023 (12)	0.0032 (12)	0.0047 (11)
C2A	0.057 (2)	0.0222 (15)	0.0453 (18)	0.0004 (14)	0.0048 (16)	0.0054 (13)
C3A	0.070 (2)	0.0227 (16)	0.053 (2)	0.0161 (15)	0.0143 (18)	0.0025 (14)
C4A	0.056 (2)	0.0313 (17)	0.0475 (17)	0.0159 (15)	0.0197 (15)	−0.0002 (14)
C5A	0.0382 (16)	0.0235 (14)	0.0277 (13)	0.0074 (12)	0.0091 (12)	−0.0014 (11)
C6A	0.0323 (15)	0.0320 (15)	0.0284 (14)	0.0060 (12)	0.0127 (12)	−0.0010 (11)
C7A	0.0230 (13)	0.0252 (13)	0.0259 (13)	0.0010 (10)	0.0109 (10)	0.0013 (10)
C8A	0.0325 (15)	0.0261 (14)	0.0273 (14)	−0.0015 (11)	0.0132 (11)	−0.0042 (11)
C9A	0.0332 (15)	0.0331 (15)	0.0271 (13)	0.0002 (12)	0.0148 (11)	0.0022 (11)
C10A	0.0236 (13)	0.0279 (14)	0.0307 (13)	−0.0026 (11)	0.0106 (11)	0.0007 (11)
C11A	0.0245 (13)	0.0288 (14)	0.0309 (14)	−0.0048 (11)	0.0090 (11)	−0.0060 (11)
C12A	0.0270 (13)	0.0290 (14)	0.0215 (12)	−0.0010 (11)	0.0080 (10)	−0.0005 (10)
C13A	0.0265 (14)	0.0333 (15)	0.0289 (14)	−0.0087 (11)	0.0049 (11)	0.0023 (11)
C14A	0.0399 (18)	0.050 (2)	0.0386 (16)	−0.0114 (14)	0.0153 (14)	0.0061 (14)
C15A	0.047 (2)	0.075 (3)	0.0393 (18)	−0.0293 (19)	0.0102 (15)	0.0118 (17)
C16A	0.066 (2)	0.044 (2)	0.0408 (19)	−0.0267 (18)	−0.0020 (17)	0.0111 (16)
C17A	0.071 (3)	0.0319 (18)	0.052 (2)	−0.0044 (17)	0.0050 (18)	0.0047 (16)
C18A	0.0449 (18)	0.0333 (17)	0.0440 (17)	−0.0015 (14)	0.0119 (14)	0.0043 (13)
C19A	0.0315 (14)	0.0154 (12)	0.0183 (12)	−0.0017 (10)	0.0033 (11)	0.0012 (9)
C1B	0.0309 (14)	0.0238 (13)	0.0230 (12)	0.0016 (11)	0.0105 (10)	−0.0031 (10)
C2B	0.0323 (15)	0.0209 (13)	0.0318 (14)	0.0005 (11)	0.0122 (11)	−0.0051 (11)
C3B	0.0399 (16)	0.0184 (13)	0.0357 (15)	0.0044 (11)	0.0158 (12)	0.0021 (11)
C4B	0.0335 (15)	0.0233 (14)	0.0245 (13)	0.0042 (11)	0.0085 (11)	0.0020 (10)
C5B	0.0269 (13)	0.0210 (13)	0.0238 (12)	0.0000 (10)	0.0100 (10)	0.0003 (10)
C6B	0.0263 (13)	0.0218 (13)	0.0210 (12)	0.0011 (10)	0.0079 (10)	0.0017 (10)
C7B	0.0254 (13)	0.0186 (12)	0.0212 (12)	−0.0009 (10)	0.0060 (10)	−0.0030 (9)
C8B	0.0331 (14)	0.0174 (13)	0.0277 (13)	−0.0037 (10)	0.0111 (11)	0.0020 (10)
C9B	0.0362 (15)	0.0214 (13)	0.0258 (13)	−0.0001 (11)	0.0149 (11)	−0.0005 (10)
C10B	0.0249 (13)	0.0193 (13)	0.0256 (12)	0.0008 (10)	0.0086 (10)	−0.0019 (10)
C11B	0.0317 (14)	0.0212 (13)	0.0287 (13)	−0.0029 (11)	0.0127 (11)	0.0000 (10)
C12B	0.0301 (14)	0.0227 (13)	0.0212 (12)	−0.0007 (10)	0.0094 (11)	0.0000 (10)
C13B	0.0250 (13)	0.0210 (13)	0.0297 (13)	−0.0029 (10)	0.0125 (11)	−0.0023 (10)
C14B	0.0294 (14)	0.0230 (13)	0.0288 (14)	−0.0026 (11)	0.0108 (11)	−0.0003 (11)
C15B	0.0328 (15)	0.0308 (15)	0.0276 (14)	−0.0052 (12)	0.0120 (11)	−0.0056 (11)
C16B	0.0357 (16)	0.0280 (15)	0.0370 (15)	−0.0052 (12)	0.0188 (13)	−0.0099 (11)
C17B	0.0419 (16)	0.0200 (13)	0.0368 (15)	0.0016 (12)	0.0173 (13)	−0.0009 (11)
C18B	0.0372 (15)	0.0253 (14)	0.0258 (13)	−0.0014 (11)	0.0137 (12)	−0.0011 (10)
C19B	0.0265 (14)	0.0231 (13)	0.0251 (13)	0.0040 (11)	0.0119 (11)	0.0052 (10)

Geometric parameters (Å, º)

Fe1—N3A	1.948 (2)	C10A—C11A	1.394 (4)
Fe1—N3B	1.950 (2)	C10A—C13A	1.487 (4)
Fe1—N1A	1.959 (2)	C11A—C12A	1.386 (4)
Fe1—N2A	1.965 (2)	C13A—C14A	1.391 (4)
Fe1—N2B	1.969 (2)	C13A—C18A	1.396 (4)
Fe1—N1B	1.970 (2)	C14A—C15A	1.401 (4)
S1A—C19A	1.635 (3)	C15A—C16A	1.366 (5)
S1B—C19B	1.638 (3)	C16A—C17A	1.360 (5)
N2B—C6B	1.296 (3)	C17A—C18A	1.393 (4)
N2B—C7B	1.444 (3)	C1B—C2B	1.375 (3)
N1B—C1B	1.348 (3)	C2B—C3B	1.381 (4)
N1B—C5B	1.367 (3)	C3B—C4B	1.387 (4)
N2A—C6A	1.291 (3)	C4B—C5B	1.379 (3)
N2A—C7A	1.434 (3)	C5B—C6B	1.448 (3)
N3B—C19B	1.161 (3)	C7B—C8B	1.384 (3)
N1A—C1A	1.344 (3)	C7B—C12B	1.386 (3)
N1A—C5A	1.359 (3)	C8B—C9B	1.388 (3)
N3A—C19A	1.163 (3)	C9B—C10B	1.392 (3)
C1A—C2A	1.390 (4)	C10B—C11B	1.400 (3)
C2A—C3A	1.376 (5)	C10B—C13B	1.491 (3)
C3A—C4A	1.383 (4)	C11B—C12B	1.390 (3)
C4A—C5A	1.383 (4)	C13B—C18B	1.394 (3)
C5A—C6A	1.450 (4)	C13B—C14B	1.396 (3)
C7A—C8A	1.389 (3)	C14B—C15B	1.393 (4)
C7A—C12A	1.391 (3)	C15B—C16B	1.383 (4)
C8A—C9A	1.392 (4)	C16B—C17B	1.383 (4)
C9A—C10A	1.399 (4)	C17B—C18B	1.385 (3)
N3A—Fe1—N3B	90.46 (9)	C11A—C10A—C9A	118.3 (2)
N3A—Fe1—N1A	94.79 (9)	C11A—C10A—C13A	120.2 (2)
N3B—Fe1—N1A	91.42 (9)	C9A—C10A—C13A	121.5 (2)
N3A—Fe1—N2A	175.45 (9)	C12A—C11A—C10A	121.5 (2)
N3B—Fe1—N2A	91.18 (9)	C11A—C12A—C7A	119.2 (2)
N1A—Fe1—N2A	80.94 (9)	C14A—C13A—C18A	118.0 (3)
N3A—Fe1—N2B	92.29 (9)	C14A—C13A—C10A	120.8 (3)
N3B—Fe1—N2B	171.98 (8)	C18A—C13A—C10A	121.2 (3)
N1A—Fe1—N2B	95.85 (8)	C13A—C14A—C15A	120.1 (3)
N2A—Fe1—N2B	86.64 (8)	C16A—C15A—C14A	120.8 (3)
N3A—Fe1—N1B	89.99 (9)	C17A—C16A—C15A	119.8 (3)
N3B—Fe1—N1B	91.25 (8)	C16A—C17A—C18A	120.6 (4)
N1A—Fe1—N1B	174.51 (8)	C17A—C18A—C13A	120.7 (3)
N2A—Fe1—N1B	94.22 (8)	N3A—C19A—S1A	179.7 (3)
N2B—Fe1—N1B	81.22 (8)	N1B—C1B—C2B	122.7 (2)
C6B—N2B—C7B	117.45 (19)	C1B—C2B—C3B	119.8 (2)
C6B—N2B—Fe1	114.75 (16)	C2B—C3B—C4B	118.6 (2)
C7B—N2B—Fe1	127.27 (15)	C5B—C4B—C3B	118.9 (2)
C1B—N1B—C5B	117.1 (2)	N1B—C5B—C4B	122.8 (2)
C1B—N1B—Fe1	129.06 (16)	N1B—C5B—C6B	113.0 (2)
C5B—N1B—Fe1	113.78 (15)	C4B—C5B—C6B	124.1 (2)
C6A—N2A—C7A	118.8 (2)	N2B—C6B—C5B	116.5 (2)
C6A—N2A—Fe1	115.50 (18)	C8B—C7B—C12B	120.0 (2)
C7A—N2A—Fe1	125.25 (16)	C8B—C7B—N2B	120.2 (2)
C19B—N3B—Fe1	162.7 (2)	C12B—C7B—N2B	119.8 (2)
C1A—N1A—C5A	117.9 (2)	C7B—C8B—C9B	119.7 (2)
C1A—N1A—Fe1	127.5 (2)	C8B—C9B—C10B	121.5 (2)
C5A—N1A—Fe1	114.59 (17)	C9B—C10B—C11B	117.9 (2)
C19A—N3A—Fe1	168.1 (2)	C9B—C10B—C13B	120.5 (2)
N1A—C1A—C2A	121.8 (3)	C11B—C10B—C13B	121.6 (2)
C3A—C2A—C1A	119.9 (3)	C12B—C11B—C10B	121.0 (2)
C2A—C3A—C4A	118.9 (3)	C7B—C12B—C11B	119.9 (2)
C3A—C4A—C5A	118.7 (3)	C18B—C13B—C14B	117.8 (2)
N1A—C5A—C4A	122.8 (3)	C18B—C13B—C10B	121.0 (2)
N1A—C5A—C6A	113.0 (2)	C14B—C13B—C10B	121.1 (2)
C4A—C5A—C6A	124.2 (3)	C15B—C14B—C13B	121.1 (2)
N2A—C6A—C5A	115.9 (2)	C16B—C15B—C14B	120.0 (2)
C8A—C7A—C12A	120.6 (2)	C17B—C16B—C15B	119.6 (2)
C8A—C7A—N2A	119.8 (2)	C16B—C17B—C18B	120.4 (2)
C12A—C7A—N2A	119.5 (2)	C17B—C18B—C13B	121.2 (2)
C7A—C8A—C9A	119.5 (2)	N3B—C19B—S1B	176.8 (2)
C8A—C9A—C10A	120.8 (2)