摘要:
The crystal packing of [M(phen)3]I7 (M~Mn, Fe) Caitlin Horn, Marcia Scudder and Ian Dance* School of Chemistry, University of New South Wales, Sydney NSW 2052, Australia. E-mail: I.Dance@unsw.edu.au Received 31st October 2000, Accepted 17th November 2000 Published on the Web 20th December 2000 3 22 6 The crystallisation, crystal structures, and crystal packing of [Mn(phen)3]I7 and [Fe(phen)3]I7 are reported. The crystal lattices are isomorphous, but there are informative small differences between the two structures. The [M(phen)3]2z complexes occur as parallel (P4AE)` chains, forming two parallel fourfold aryl embraces (P4AE) with adjacent cations. The polyiodide components occur between the chains, and in the (phen)2 grooves of the complexes. The stoichiometry {I7}22 is comprised structurally of discrete I32 and half of centrosymmetric [I8]22 units.These [I8]22 units contain twofold 50 : 50 disorder, and are either zig-zag I822, or I2 plus I622. Details of the disorder are different in the two crystals, reØecting the soft IºI potentials involved. The I 22 ion is normal, but the I species, as a centrosymmetric pair of linear I 2, appears to be unprecedented. The disordered polyiodide segments are positioned in a Ælled aryl box motif formed by (phen)2 grooves from complexes in adjacent (P4AE)` chains. These crystal structures illustrate again the pattern of complementary orthogonality of phen ligands and polyiodide segments. Introduction In other papers we have described compounds [M(phen)3]Ix, for x~8,1 12,2 143 and 18,3 principally for M~Fe.These reports have described the crystallisation, crystal structures, crystal packing, polymorphism, and crystal supramolecular motifs of these compounds. Dimorphs of [CuI(phen)2]I3 have also been described.4 Here we present the crystal structures and crystal packing for [Mn(phen)3]I7 and [Fe(phen)3]I7, which are isomorphous, but are unusual in that some of the polyiodide segments are disordered, with different disorder in the two crystals. This disorder is signiÆcant in the crystal supramolecularity of polyiodides with [M(phen)3]2z cations, as will be discussed. As in previous analyses of [M(phen)3]Ix crystals, the primary questions concern the embraces between [M(phen)3]2z cations,5 the polyiodide catenation,6±8 and the interactions between polyiodide chains and [M(phen)3]2z cations.Each cation contains three grooves between pairs of ligand planes, and segments of polyiodide chains can Æt snugly into these grooves, running parallel to the ligand faces. In addition, a polyiodide chain can surround the periphery of a ligand plane, using weak C±HºI hydrogen bonds. Experimental [Fe(phen)3](BF4)2 was precipitated by addition of NaBF4 to FeSO4z3phen in water, and [Fe(phen)3]I2 was crystallised by addition of NaI in acetone to [Fe(phen)3](BF4)2 in acetone. Crystallisation of [Fe(phen)3]I7 [Fe(phen)3]I7 was crystallised from solutions prepared from mixtures of [Fe(phen)3]I2 and I2 in various solvent systems. Solvents and concentrations for these experiments are provided in Table 1, and details of the procedures are: Experiments 1±5.A standard 5 mM solution of [Fe(phen)3]I2 (0.425 g, 0.50 mmol) was prepared in 100 mL of CH3CN. A standard solution of I2 (3.173 g, 25 mmol) was DOI: 10.1039/b008751n This journal is # The Royal Society of Chemistry 2001 Paper 8 prepared in 250 mL of CH3CN, giving a solution 0.1 M in I2. Reaction mixtures were set up with the molar ratios of I2 to [Fe(phen)3]I2 speciÆed in Table 1, and left undisturbed for slow evaporation of the solvent. Product crystals were collected after 24 h. Experiments 6±8. The standard solution was prepared in 100 mL of CH3CN, by dissolving [Fe(phen)3]I2 (0.425 g, 0.50 mmol), then adding I2 (0.635 g, 2.50 mmol) with stirring and warming to ca.60 �C. From the resulting solution which was 5 mM in [Fe(phen)3]I2 and 25 mM in I2, 10 mL aliquots were placed in sealed sample tubes, and distilled water was added in varying ratios, as given in Table 1. All solutions were then kept at room temperature overnight, and samples collected after 24 h. Experiments 9±10. A standard solution was prepared in 100 mL of DMF, by dissolving [Fe(phen)3]I2 (0.850 g, 1.00 mmol), then adding I2 (1.269 g, 5.00 mmol) with stirring. The resulting solution was 10 mM in [Fe(phen)3]I2 and 50 mM in I2. From this standard solution 5 mL aliquots were transferred to sealed sample tubes, and varying amounts of the solvents H2O and Et2O were added in the ratios given in Table 1.Crystals were collected after 2 d. [Fe(phen)3]I7 is stable in air, and to loss of I2 under ambient conditions. Crystallisation of [Mn(phen)3]I7 The preparation of the precursor [Mn(phen)2I2] has been described previously.1 A 4.54 mM solution of [Mn(phen)2I2] (0.335 g, 0.50 mmol) was prepared in 100 mL of CH3CN plus 10 mL water. This was treated with a 0.1 M solution of I2 in CH3CN, such that the mole ratio of I2 to [Mn(phen)2I2] was 5, and the concentration of Mn was 3.7 mM. Crystals of [Mn(phen)3]I7 and [Mn(phen)3]I8 grew concurrently, and were collected after 1 d and washed with Et2O. These crystals showed some loss of I2 after several days under ambient conditions. After crystallisation, all products were collected by Æltration, 1 CrystEngComm, 2000, 36, 1±5Table 1 Crystallisation experiments yielding [Fe(phen) Solvent system Expt1 CH3 CN 2 CH3 CN 3 CH3 CN 4a (crop 2) CH3CN 5 CH3 CN 6 CH3 CN:H2O 10 : 3 7 CH3 CN:H2O 5 : 2 CH3CN:H2O 5 : 3 DMF:H2O2 : 1 8b 910c (crop 2) DMF:Et2O1 : 5 aThe Ærst crop of crystals was [Fe(phen)3]I12.bFrom this solution crystals of [Fe(phen)3]I7, [Fe(phen)3]I8 and [Fe(phen)3]I12 grew concurrently. cThe Ærst crop of crystals was [Fe(phen)3]I6?DMF. washed with diethyl ether, and identiÆed by single crystal diffraction and microscopic examination of crystal habit. Crystal structures Data were collected at ambient temperature using a Nonius CAD4 diffractometer with graphite monochromated Mo-Ka radiation (l~0.7107 A ).Metal and iodine atoms were reÆned anisotropically, while each phen ligand was reÆned with thermal motion described by a 12 parameter TL group (where T is the translation tensor, L is the libration tensor). Hydrogen atoms of the cations were included in calculated positions and were included in the group thermal for that ligand. Details of data collection and reÆnement are given in Table 2. Results The crystal lattices of [Fe(phen)3]I7 and [Mn(phen)3]I7 are isomorphous. The molecular geometries of the [M(phen)3]2z complexes are normal, with average metal±nitrogen bond lengths of 1.98 A for M~Fe and 2.23 A for M~Mn. [Mn(phen)3]2z commonly shows distortions from regular octahedral geometry, with the angle between the normals to the ligand planes deviating from 90� by as much as 30�,1 but such distortion does not occur in [Mn(phen)3]I7 where the angles between the ligand planes are 87.2, 88.0, 83.3�. For Table 2 Crystal data for [Fe(phen)3]I7 and [Mn(phen)3]I7a Mo/mm21 max Properties Formula MCrystal system Space group a/A b/A c/A a/� b/� c/� V/A 3 Dc/g cm23 Zm2h Crystal decay(%) Min trans.factor Max trans. factor Unique reØections Observed reØections Rmerge RRw a [Fe(phen) [Mn(phen)3]I7 C36H24FeI7N6 C36H24I7MnN6 1484.8 1483.9 Triclinic Triclinic P1ÅP1Å 12.897(5) 13.100(6) 13.343(6) 13.506(6) 13.755(8) 13.843(7) 81.75(3) 79.64(3) 72.90(4) 71.94(4) 65.11(4) 65.05(4) 2052(2) 2108(2) 2.40 2.34 2 2 5.61 50 50.28 0.64 7177 4623 0.011 0.051 0.069 Click here for full crystallographic data (CCDC nos.151832 and 151833). 2 CrystEngComm, 2000, 36, 1±5 3]I7 Conc. of [Fe(phen)3]2z/mM Mole ratioI2 : [Fe(phen)3]I2 4.2 4.0 3.3 2.5 2.2 3.9 3.6 3.1 6.7 1.7 4 : 1 5 : 1 10 : 1 20 : 1 25 : 1 5 : 1 5 : 1 5 : 1 5 : 1 5 : 1 [Fe(phen)3]I7 the angles between the ligand planes are 85.2, 88.7, 86.0�. Crystal packing of [Fe(phen)3]I7 and [Mn(phen)3]I7 The predominant feature of the structures is the occurrence of parallel chains of complex cations surrounded by polyiodide Fig. 1 The crystal packing of [Fe(phen) chains of [Fe(phen) comp purple (I for unit cell packing diagram of [Fe(phen)3]I7.Click here for unit cell packing diagram of [Mn(phen)3]I7. 3]I7 ` Fig. 2 The (P4AE) chain in crystalline [Fe(phen) and [Mn(phen)3]I7. The red lines represent P4AE, with MºM distances marked for [Fe(phen)3]I7. The corresponding MnºMn distances for [Mn(phen)3]I7 are 9.72 and 9.27 A . 5.41 46 16 0.29 0.58 5746 3570 0.023 0.066 0.081 Fig. 3 Unique atom numbering for the centrosymmetric [I8]22 unit in [Fe(phen)3]I7 and [Mn(phen)3]I7. 2 Product [Fe(phen) [Fe(phen) [Fe(phen) [Fe(phen) [Fe(phen) [Fe(phen) [Fe(phen)3]I7 3]I7 3]I7 3]I7 3]I7 3]I7 3]I7 [Fe(phen)3]I7 and [Fe(phen)3]I8 3]I7 [Fe(phen) [Fe(phen)3]I7 3]I7, projected along parallel 3]2z complexes (Fe red) surrounded by polyiodide 22 segments) and gold (I 2).Click here 3 8 3]I7Fig. 4 The disordering of the [I8]22 unit in [Fe(phen)3]I7 and [Mn(phen)3] I7, with two adjacent [I8]22 units drawn for each structure. Centres of inversion occur within and between the [I8]22 units. The equally occurring structures are labelled A and B, with the disordered atoms coloured blue. 22 Unique interatomic distances are marked. Component A is zig-zag I8 3]2z anions, as shown in Fig. 1. The chains of [M(phen) complexes are inÆnite zig-zag P4AE chains,5 as illustrated in Fig. 2. Each [M(phen)3]2z complex forms two slightly different P4AE embraces (comprised of one OFF and two EF motifs) with its neighbours in the chain. Polyiodides in [Fe(phen)3]I7 and [Mn(phen)3]I7 2 7}22, 8]22 is comprised of a discrete I3 2 The polyiodide component, with formal stoichiometry {I ion and half of a disordered [I unit.The I3 ion, I1±I2±I3, is close to symmetrical and linear, 2 22 6 Fig. 5 The (P4AE)` cation chain in [Fe(phen)3]I7 surrounded by polyiodide species. Two of the metal atoms of the chain of four cations are obscured, but their positions are indicated by the arrows. The I3 ions are gold and the components of the [I8]22 unit are purple: (a) disorder component A with the central I4 segment of I822 in the (phen)2 groove of one complex; (b) disorder component B with the I2 centred in the groove, and the I shown in the upper region and marked with an ellipse. ; component B is I 22zI2. 6 2 and separated from other polyiodide components by IºI about 4.4 A . The I3 dimensions are I±I 2.87, 2.93 A , I±I±I 178� for [Fe(phen)3]I7 and 2.86, 2.94 A , 177� for [Mn(phen)3]I7.8]22 component is disordered differently in the two 8 6 6 3 The [I crystals, although it is twofold disorder with approximately equal occurrence in each structure. Further, these [I8]22 units are near each other in chains (see Fig. 1: purple atoms) and the disordering has consequences between [I8]22 units as well as within them. The atom numbering is given in Fig. 3, and the disorder components A and B for the two structures are presented in Fig. 4. In the Fe structure one (I6) of the four crystallographically unique atoms is disordered, while in the Mn structure three of the unique atoms are disordered, although the shifts of I4 and I5 are small, and the overall effect of disordering is not signiÆcantly different in the two structures.As shown by the bonding connections drawn in Fig. 4, the alternative structures are (A) zig-zag I 22 and (B) I 22 plus I2. This assignment is based on bonding distances less than 3.32 A and intermolecular distances greater than 3.76 A , and is relatively unambiguous in the context of the unusual continuum of IºI distances in iodine and polyiodide structures.9 The I 22 ion in structure B is effectively two parallel I 2 ions end-overlapped around a centre of inversion. We have searched the Cambridge Crystallographic Database for this I6 geometry, and found no other examples of this ion, which Ælls a gap in a predicted polyiodide series.8 The distances shown in Fig.4 illustrate the general softness of the IºI interatomic potential, with variations of the order 0.2 A between bonds in the Fe and Mn structures: a variation of 0.2 A is highly signiÆcant in terms of the crystallographic precision, but hardly signiÆcant in terms of the concomitant energy variation.9 Polyiodideº[M(phen)3]2z association 3]I7) how the I32 and Fig. 1 shows that the (P4AE)` chains of [M(phen)3]2z complexes are completely surrounded by polyiodide components. We describe here Ærst the association of the polyiodides with the surfaces of the complexes, and then the surroundings of polyiodides.Fig. 5 shows (for [Fe(phen) [I8]22 components are associated with the grooves and edges of phen ligands in the (P4AE)` chain of complexes. The [I8]22 disordering places either the I2 at the centre of I822 (Fig. 5(a)) 3 CrystEngComm, 2000, 36, 1±52 2 3 Fig. 6 The environment of a discrete I3 ion in [Fe(phen)3]I7: (a) shows the end-on and surface interactions with three different phen ligands; (b) shows the individual C±HºI interactions (HºIv3.4 A ), as black and white candystripes, between a single I ion and six surrounding cations. Ligands which do not interact with that anion are omitted. or the I2 between I622 (Fig. 5(b)) in the groove formed by a pair of phen ligands of one [M(phen)3]2z complex. The I3 sections 8]22 units are peripheral to phen ligands of the next ` chain.The discrete I32 ions are not in a of the [I complex in the (P4AE) groove, but point their ends at the faces of phen ligands, and 2 skirt the periphery of phen ligands. Fig. 6 shows the surroundings of the discrete I3 ion. Each 2 end is directed towards the face of a phen ligand (Fig. 6(a)), while sides of I3 lie both along the face of a phen ligand and around the edges of phen ligands. This latter positioning is due to a relatively large number of C±HºI hydrogen bonds, which 8]22 are detailed in Fig. 6(b). Fig. 1 shows that (P4AE)` chains come together in two regions. One approach is around the central region of the [I component, while the other involves the terminal I3 segments of 8]22 component and the discrete I32 ions.The four I 8]22 component, shown in a the [I atoms of the central section of the [I groove between two phen ligands in Fig. 5, are enclosed by a [I second such groove, generated by the centre of inversion in 8]22. This forms a (phen)4 box around the polyiodide. This is 4 4 CrystEngComm, 2000, 36, 1±5 the Ælled aryl box (FAB) supramolecular motif which we have identiÆed in other crystal packings,3,5,10,11 and which occurs ± unnoticed ± in the crystal structures of [Mn(phen)3]I612 and [Cu(dafone)3]I12.13 As shown in detail in Fig. 7 the FAB contains either the linear I4 segment of the z-shaped I822 ion or an I2 between I622 at the open ends of the box. The distances between the I atoms in the box and the phen faces of the box are about 3.8 A .2 2 22 3 22 The second region between P4AE chains contains the terminal I3 segments of the I8 ion and isolated I3 2 ions (Fig. 1). It can be seen from Fig. 6(a) that the isolated I3 ions are wedged into grooves formed by pairs of parallel phen ligands. These ligands originate from different (P4AE)` chains and so determine the spacing of cations between the chains in this direction. As a consequence, the I 2 portions from the ends of the I8 ions do not make maximum contact with the surrounding phen ligands, and disorder is possible. The atom relocation in the disorder is different in the two structures, presumably related to the different overall dimensions of [Fe(phen)3]2z and [Mn(phen)3]2z.Discussion The two compounds [M(phen)3]I7 (M~Mn, Fe) are members of an extensive series of compounds [M(phen)3]Ix, including 13 different crystals where M~Fe.10,14 The crystal lattices of the two [M(phen)3]I7 compounds are isomorphous, but there are some subtle and informative differences between the two crystal structures, indicating that in this area of research isomorphous lattices should be investigated in full. Amongst other Mn/Fe pairs, [M(phen)3]I8 (M~Mn, Fe) have very different crystal packing,1 while [Mn(phen)3]I12 is isomorphous with one of the trimorphs of [Fe(phen)3]I12.2 High-spin [Mn(phen)3]2z is larger than low-spin [Fe()3]2z, and [Mn(phen)3]2z is sometimes quite severely distorted from octahedral coordination, but this is not the case in [Mn(phen)3]I7. The overall crystal packing for [M(phen)3]I7, as a chain of embracing [M(phen)3]2z cations surrounded by polyiodides closely associated with the surfaces of the phen ligands, is a type observed in other compounds.1,2 The local motifs are normal, and the pattern of complementary orthogonality of phen ligands and polyiodide segments is maintained.The stoichiometry {I7}22 is comprised structurally of I32, 22, I 3 22 622 zig-zag I8 2 and I622. All except I622 are already wellknown. The species I622, as a tight centrosymmetric dimer of I 2, appears not to have been reported previously. In [M(phen)3]I7, I622 is part of a polyiodide disorder, in which iodine atoms have alternative locations within an aryl box generated by the (phen)2 grooves of two metal complexes.It seems that these iodine atoms can `rattle' in the box, and so the presence of the I6 moiety is related to, and maybe controlled by, its immediate surrounds. The disordering of the atoms in I 22, and the variability of its internal dimensions, indicate that it is not a strongly stabilised species. Further preparation of I6 may depend strongly on the supramolecularity of associated cations. 3 Disorder of polyiodide atoms is rare in the [M(phen)3]Ix and related compounds we have investigated, and is not present in any of the other twelve [Fe(phen)3]Ix crystals. Interrogation of the CSD indicates that disorder of polyiodide chains occurs in about 10% of structures±slightly more frequently for structures containing only linear I 2 ions, and slightly less frequently when the polyiodide anion has elbows.The polyiodide disordering observed here in two [M(phen)3]I7 crystals provides a collection of geometries (Fig. 4) that illustrate nicely via distance variability the calculated softness of IºI potentials.9Fig. 7 (a) The aromatic box formed by four phen ligands in [Mn(phen)3]I7. (b) and (c) show space Ælling views, with (b) in the same orientation as (a) and (c) rotated by 90�. Parts (d), (e) and (f) show the aromatic box Ælled with I822 and (g), (h) and (i) show it Ælled with I2 and surrounded by two I622 units. These are the disordered alternatives. (e) and (h) have been rotated by 90� and (f) and (i) are space Ælling views.Acknowledgement This research was supported by the Australian Research Council and UNSW. Crystallography was performed by D. C. Craig. References 1 C. Horn, M. L. Scudder and I. G. Dance, CrystEngComm, 2001, 1. http://www.rsc.org/ej/ce/2001/b008381j/index.htm 2 C. Horn, M. L. Scudder and I. G. Dance, CrystEngComm, 2000, 9. http://www.rsc.org/ej/ce/2000/b001706j/index.htm 3 C. Horn, M. L. Scudder and I. G. Dance, CrystEngComm, 2001, 2. http://www.rsc.org/ej/ce/2001/b008107h/index.htm 4 C. Horn, B. F. Ali, I. G. Dance, M. L. Scudder and D. C. Craig, http://www.rsc.org/ej/ce/2000/ 2. CrystEngComm, 2000, A910231K/index.htm 5 V. M. Russell, M. L. Scudder and I. G. Dance, J. Chem. Soc., Dalton Trans., submitted. 6 P. Coppens, in Extended Linear Chain Compounds, ed. J. S. Miller, Plenum Press, New York, 1982, pp. 333±356. 7 A. J. Blake, F. A. Devillanova, R. O. Gould, W.-S. Li, V. Lippolis, S. Parsons, C. Radek and M. Schroder, Chem. Soc. Rev., 1998, 27, 195. 8 P. H. Svensson, Synthesis, Structure and Bonding in Polyiodide and Binary Metal Iodide±Iodine Systems, PhD, Lund University, Lund, Sweden, 1998. 9 I. G. Dance and C. Horn, to be published, 2001. 10 C. Horn, The Crystal Supramolecularity of some Metal-Phenanthroline Polyiodides, Honours, University of New South Wales, Sydney, 1999. 11 C. Horn, I. G. Dance and D. C. Craig, to be published, 2001. 12 D. Ramalakshmi, K. R. N. Reddy, D. Padmavathy, M. V. Rajasekharan, N. Arulsamy and D. J. Hodgson, Inorg. Chim. Acta, 1999, 284, 158. 13 S. Menon and M. V. Rajasekharan, Inorg. Chem., 1997, 36, 4983. 14 C. Horn and I. G. Dance, to be published, 2001. 5 CrystEngComm, 2000, 36, 1&plus
ISSN:1466-8033
DOI:10.1039/b008751n
出版商:RSC
年代:2000
数据来源: RSC