Metodología general para el establecimiento de indicadores de gestión

With silver(I) triflate (3.18)

Ligand 3.10 was combined with silver(I) triflate resulting in the formation of crystals suitable for X-ray crystallography. The structure solved in the monoclinic space group P21/c. The asymmetric unit, shown in Figure 3.25, consists of one silver atom, one non-

coordinating triflate anion and one molecule of 3.10 with an overall structure of a [2+2] macrocycle.

Each macrocycle contains two silver atoms and two molecules of 3.10. The silver atoms have approximate trigonal planar geometry and are coordinated to two alkenes from one ligand and one η2 arene from the second ligand. As in 3.17, the silver has attached to the naphthalene ring in one of the predicted positions.122 Also similar to the previous complex, 3.17, the distance between the centroid of the two carbons in the η2 interaction and the silver atom in 3.18 is marginally longer than the distance between the olefinic carbon centroid and silver. The [2+2] macrocycle is formed by ligand 3.10 coordinating to one silver atom through chelation of the alkenes from both allyl ether arms and bridging to the second silver atom through an η2 coordination at the C5,C6 position on

the naphthalene ring. This is the only example of the chelation of allyl ether arms in this thesis. The Ag···Ag separation across ligand 3.10 is 7.34 Å.

Figure 3.25 – View of discrete [2+2] macrocyclic 3.18. Hydrogen atoms

have been excluded for clarity. Selected bond lengths (Å) and angles (°): Ag1-C5A 2.472(3), Ag1-C6A 2.581(3), Ag1-C5A,C6A 2.433(3), Ag1-C10 2.503(3), Ag1-C11 2.510(3), Ag1-C10,C11 2.416(3), Ag1-C13 2.481(3), Ag1-C14 2.425(3), Ag1-C13,C14 2.360(3), C5A,C6A-Ag1-C10,C11

111.9(1), C5A,C6A-Ag1-C13,C14 126.9(1), C10,C11-Ag1-C13,C14

119.9(1).

Within the crystal packing the discrete units stack with other units through shifted π-π

stacking interactions and the non-coordinated triflate anion weakly hydrogen bonds through its oxygen atoms with hydrogen atoms in ligand 3.10.

With silver perchlorate (3.19)

Under the same conditions as for the formation of 3.18, silver(I) perchlorate was reacted with ligand 3.10 also yielding crystals suitable for X-ray analysis. The structure solved in the triclinic space group P-1. The asymmetric unit contains one disordered silver atom, one ligand 3.10, one half of a water molecule and one disordered non-coordinating perchlorate anion. The overall structure is a [2+2] macrocycle very similar to 3.18.

The disorder in the silver is over two positions, with each position having 50 % occupancy. Not enough information is available to determine whether each macrocycle contains two silver atoms in each position of disorder, or whether the macrocycles contain silver atoms exclusively occupying one position or the other. It is likely that all three possibilities are occurring. Figure 3.26 shows the [2+2] macrocycle with two silver atoms, one occupying each of the positions.

Figure 3.26 – View of the discrete [2+2] macrocycle 3.19 with both

occupancies of silver displayed. Hydrogen atoms and counter anions have been omitted for clarity. Selected bond lengths (Å) and angles (°): Ag1- C5A 2.600(4), Ag1-C6A 2.436(4), Ag1 C5A,C6A 2.425 (4), Ag1-C10 2.230(6), Ag1-C11 2.220(7), Ag1-C10,C11 2.125(7), Ag1-C14 2.598(5), Ag1'-C5 2.429(4), Ag’-C6 2.596(4), Ag1’-C5,C6 2.420(4), Ag’-C13A 2.264(6), Ag1’-C14A 2.224(5), Ag1’-C13,C14 2.146(6), Ag1’-O20 2.597(8), C5A,C6A-Ag1-C14 128.9(2), C5A,C6A-Ag1-C10,C11 123.6(2), C10,C11-Ag1-C14 107.3(2), O20-Ag1’-C5,C6 101.2(2), O20-Ag1’- C13A,C14A 102.7(2), C5,C6-Ag1’-C13A,C14A 137.8(2).

In both positions of disorder silver atoms are three coordinate; Ag1 has close to trigonal planar geometry and Ag1’ has a more T shaped geometry. Ag1 has one alkene (C10,C11) very closely bound, an η2 interaction with the naphthalene ring at the C5,C6 position and

a weaker interaction with one carbon from the second alkene. The second position of silver, Ag1’, has an η2 interaction with the naphthalene ring at the C5,C6 position and one of the alkenes closely bound (C13,C14). Ligand 3.10 is no longer chelating to the silver atoms in this position as the second alkene is non-coordinating. The oxygen of the water molecule, O20, is shown interacting with Ag1’ in Figure 3.26 but it can also weakly interact with Ag1 (Ag1-O20 2.61 Å), however it only has 50 % occupancy and may only be associated with Ag1’. The Ag···Ag separation in this macrocycle is slightly shorter than in 3.18 with an average distance of 7.02 Å. As in 3.18, the silver has coordinated to the naphthalene ring in the C5,C6 position.

The macrocycles pack in a manner much the same as 3.18, where the discrete units stack above and below each other with π-π stacking interactions between the naphthalene rings of adjacent units. The perchlorate anion is involved in weak hydrogen bonds betweens its oxygen atoms and hydrogen atoms on ligand 3.10.

3.8 Complexes of 2,3-Di(allyloxy)naphthalene

With silver(I) hexafluorophosphate (3.20)

Ligand 3.11, dissolved in chloroform, was mixed with an acetone solution of silver(I) hexafluorophosphate. Diethyl ether was allowed to diffuse into the combined solution and upon evaporation, crystals suitable for X-ray analysis formed. The structure solved in the triclinic space group P-1. The asymmetric unit of 3.20 consists of one silver atom disordered over two positions, one molecule of 3.11, and a highly disordered, non- coordinating hexafluorophosphate counter anion. Figure 3.27 shows the contents of the unit cell including both positions of the silver atom.

Figure 3.27 - View of the unit cell contents of 3.20, showing both

positions of occupancies of silver. The hydrogen atoms, counter anion and further disorder have been omitted for clarity. Selected bond lengths (Å) and angles (°): Ag1-O1A 2.425(5), Ag1-O2A 2.482(4), Ag1-C10C 2.407(6), Ag1-C11C 2.269(6), Ag1-C10C,C11C 2.242(6), Ag1-C6 2.562(8), Ag1'-O2 2.323(4), Ag1'-C6A 2.580(9), Ag1'-C7A 2.409(7), Ag1'- C10B 2.567(7), Ag1’-C11B 2.518(7), Ag1’-C10B,C11B 2.454(7), O1A- Ag1-O2A 62.8(2), O1A-Ag1-C10C,C11C 121.6(3), O2A-Ag1-C10C,C11C 127.3(2), O1A-Ag1-C6 107.8(2), O2A-Ag1-C6 114.1(2), C6A-Ag1’- C10C,C11C 113.0(2), O2-Ag1’-C6A,C7A 117.8(2), O2-Ag1’-C10B,C11B 109.1(2), C6A,C7A-Ag1’-C10B,C11B 113.8(2).

In this structure the silver is disordered over two positions, with each position having 50 % occupancy. The silver is pulled in two opposing directions, where one direction favours the chelation of the oxygen atoms in the allyl ether arms and the other favours the

η2

coordination of the naphthalene ring. In the first position, Ag1, the silver is four coordinate with a calculate τ4 value of 0.79 indicating a distorted trigonal pyramidal

as well as one alkene from an allyl ether arm and one carbon from the naphthalene ring. This position favours the chelation of the allyl ether oxygen atoms at the expense of the

η2

coordination to the naphthalene ring. In the second position, Ag1’, the silver is three coordinate with approximate trigonal planar geometry. It coordinates to one oxygen atom and one alkene from an allyl ether arm as well as the naphthalene ring via an η2 fashion. This position of the silver atoms favours the η2 coordination to the naphthalene ring at the expense of the chelation of the oxygen atoms from the allyl ether arms.

Ligand 3.11 is coordinated to three silver atoms and bridges them in three different ways. Firstly through η2 or η1 coordination of the naphthalene ring to the silver atom and bridging to another silver atom through either the coordination of one, or the chelation of two, of the oxygens in the allyl ether arms. The second mode of bridging is through η2 or

η1

coordination of the naphthalene ring to silver then connecting to another silver atom through the coordination of an alkene on one of the allyl ether arms. The last type of bridging is through the coordination of one, or the chelation of two, of the oxygen atoms in the allyl ether arms to silver and then bridging to another silver atom through an alkene on one of the allyl ether arms. One of the alkenes in an allyl ether arm is non- coordinating and is disordered over two positions.

Unlike the previous two examples of η2 coordination of a naphthalene ring this structure contains coordination to the aromatic system at the C6,C7 position, one of the longer bonds. As a result of the coordination of a silver atom the bond length of C6-C7 (1.35(1) Å) is significantly shorter than in the free ligand, C6-C7 (1.417(5) Å). Conversely, the bonds connecting the adjacent carbons are slightly longer, C5-C6 1.41(1) Å, C7-C8 1.40(1) Å, compared to the free ligand, C5-C6 1.376(4) Å, C7-C8 1.383(5) Å. This suggests that the electron density is being drawn from the adjacent bonds (C5-C6 and C7-C8) and localised in the C6,C7 bond. Other bond distances around the naphthalene ring are within experimental error of each other with the exceptions of C2-C3 1.42(1) Å and C8A-C4A 1.40(1) Å, which are both shorter compared to the free ligand.

The Ag···Ag separation across 3.11, Ag1B···Ag1A in Figure 3.28, in 3.20 is an average of 8.32 Å. This is longer compared to both 3.18 (7.34 Å) and 3.19 (7.02 Å) which is to be expected as the ligand in 3.20 is bridging over the longer axis of the naphthalene ring, rather than the shorter axis as in 3.18 and 3.19. Other Ag···Ag distances include 10.17 Å between Ag1B and Ag1D and 5.28 Å between Ag1A and Ag1D.

Figure 3.28 - Section of the one-dimensional polymer 3.20 showing non-

coordinating olefinic carbons C13 and C14. Only one of the occupancies of the silver atom is displayed.

The complex is a one-dimensional polymer with staggered π-π interactions between naphthalene rings, within and between polymer strands. Within the crystal packing there are also numerous weak hydrogen bonding interactions between the hydrogen atoms in ligand 3.20 and fluorine atoms on the hexafluorophosphate counter anion.

3.6 Complexes of 2,6-Di(allyloxy)naphthalene

With silver(I) tetrafluoroborate (3.21)

Ligand 3.12 was dissolved in chloroform and the resulting solution added to solid silver(I) tetrafluoroborate. The chloroform was then allowed to evaporate yielding crystals suitable for single crystal X-ray analysis. The structure was solved in the monoclinic space group P21/c. However, while the solution makes chemical sense, the

R(int)‡, R(sigma)§ and R1** values are poor, and it is likely due to twining. A second

crystal was analysed and similar problems occurred. The asymmetric unit, shown in Figure 3.29, contains two crystallographically independent half ligands, one silver atom and one non-coordinating tetrafluoroborate anion.

Figure 3.29 – View of the asymmetric unit of 3.21. Hydrogen atoms and

counter anions are omitted for clarity. Bond lengths and angles are not listed due to the poor refinement.

In this structure, the silver atoms are three coordinate with approximate trigonal planar geometry. Each silver atom has two alkenes and one η2 naphthalene coordinated. As in the free ligand, the two molecules of 3.12 lie on crystallographic centres of inversion.

Ligand 3.12 bridges silver atoms in two different ways. In the first, the ligand simply bridges two silver atoms by coordination of both alkenes in the allyl ether arms. In the second, it bridges four silver atoms in a remarkably similar manner to ligand 3.9 in complex 3.17. The ligand is tetradentate and bridges two silver atoms through the alkenes in the allyl ether arms, as they did above, as well as bridging a further two silver atoms through η2 coordination of the naphthalene ring at the C3,C4 and C7,C8 positions.

‡

R(int) is a measure of the agreement between observed symmetry-equivalent data. §

R(sigma) is a measure of the variance in the intensities of reflections. ** _R

Approximate distances between silver atoms measured the two allyl ether arms of ligand

3.12, Ag1···Ag1A and Ag1D···Ag1H in Figure 3.30(a), are 13.8 Å and 13.5 Å

respectively. These are the longest Ag···Ag separations achieved by the linear allyl ether ligands; 2.9, 3.8, 3.9 and 3.12. The approximate Ag···Ag separation between Ag1 and Ag1B is 7.10 Å which is comparable to the value of 7.38 Å occurring between similarly bridged silver atoms in 3.17.

a) b) L M M M M L M M L M M L M L M L M M M M L M M L M M L M L M L L L L L L L L L L

Figure 3.30 – a) View of the two-dimensional nature of polymer 3.21 b)

The structure can be considered a one-dimensional necklace polymer, similar to 3.17, that are further bridged by further molecules of 3.12 in a bidentate manner to give an overall two-dimensional sheet. There are staggered π-π stacking interactions between ligands within a polymer sheet and the two-dimensional sheets stack upon each other in a ABAB manner with weak Ag···F-BF3 and CH···F interactions between them.

3.7 Complexes of 2,7-Di(allyloxy)naphthalene

With silver(I) triflate (3.22)

Ligand 3.13 was reacted with silver(I) triflate in an acetone/chloroform solution with diethyl ether diffusion. Slow evaporation of the solvents yielded a crystalline product suitable for X-ray analysis. The structure solved in the triclinic space group P-1. Figure 3.31 shows the asymmetric unit which contains; one silver atom, one ligand 3.13 and a coordinated triflate anion.

Figure 3.31 - View of the asymmetric unit of 3.22. Hydrogen atoms have

been omitted for clarity. Selected bond lengths (Å) and angles (°): Ag1- C10 2.514(3), Ag1-C11 2.543(3), Ag1-C10,C11 2.440(3), Ag1-C13A 2.477(3), Ag1-C14A 2.390(3), Ag1-C13A,C14A 2.342(3), Ag-O21 2.381(2), Ag1-O23 2.463(2), C10,C11-Ag1-C13A,C14A 133.8(1), C10,C11-Ag1-O21 115.5(1), C10,C11-Ag1-O23A 86.81(9), C13A,C14A- Ag1-O21 105.2(1), C13A,C14A-Ag1-O23A 116.6(1), O21-Ag1-O23A 88.91(7).

Similar to the previous structure, 3.17 with two bridging triflate anions, the silver in this complex also has distorted trigonal pyramidal geometry with a calculated τ4 value of

0.78. Two oxygen atoms from different triflate counter anions are coordinated and, in this case, two alkenes from the allyl ether arms are coordinated rather than one alkene and one η2 arene as in 3.17. The Ag···Ag separation across ligand 3.13, Ag1E and Ag1F in Figure 3.32(a,b) is 12.31 Å and is, as expected, much greater than the 8.45 Å Ag···Ag separation seen across the related meta ligand 2.8 in complex 2.15. The Ag···Ag separation between silver atoms doubly bridged by triflate anions, Ag1A and Ag1F, is 5.88 Å which is marginally longer than the Ag···Ag distance of 5.22 Å between two silver atoms bridged by a single triflate counter anion in 3.17.

a)

b)

Figure 3.32 – View of two neighbouring strands of the one-dimensional

polymer 3.22. Hydrogen atoms have been omitted for clarity. a) Looking at the silver atoms doubly bridged by the triflate anions b) same polymer strands rotated 90 º viewing the silver atoms doubly bridged by ligand

The silver atoms are alternately doubly bridged by molecules of 3.13 and then doubly bridged by two triflate anions to form a one-dimensional polymer. Figure 3.32 displays the one-dimensional polymeric character of 3.22. Another way to describe this polymer is to say that it is a chain of [2+2] macrocycles, consisting of two silvers that are doubly bridged by two molecules of 3.13, which in turn are linked together by bridging counter anions.

The naphthalene rings within each macrocycle π-π stack in a staggered arrangement with respect to each other (3.60-3.62 Å) and also interact with macrocycles from neighbouring polymer strands in a similar manner (3.39 Å). Triflate fluorine atoms, as in 3.17, are forced into close proximity. The shortest distance between fluorine atoms on adjacent triflate anions is 2.827(8) Å and again arises from close crystal packing rather than attractive F···F interactions.135-138

3.9 Complexes of 2,2’-Di(allyloxy)-1,1’-binaphthalene

With silver perchlorate (3.23) and (3.24)

The racemic mixture 3.14a was initially used and was successfully reacted with silver(I) perchlorate in a chloroform/acetone solution. The resulting crystalline product, 3.23, was analysed by X-ray crystallography and solved in the monoclinic space group P21/c. This

space group is centrosymmetric which confirms the presence of both complex enantiomers within the same crystal. The asymmetric unit contains one ligand, two silver atoms, two coordinated counter anions, two coordinated acetone molecules and one solvent molecule with an overall discrete M2L structure.

While the R(int) and R(sigma) values are acceptable the R1 value is high. This is likely

due to other solvent molecules that were lost previous to, or during, the data collection leaving unassignable electron density in the difference map. A second data collection was done on a different crystal with similar problems occurring.

Figure 3.33 – View of the core unit of complex 3.23. Bond lengths and

angles are not displayed due to poor refinement.

Both silver units are four coordinate with approximate trigonal pyramidal geometry. Each silver atom has one ligand 3.14a coordinated to it through an alkene on the allyl ether arm and through η2 coordination of the naphthalene ring at the C7,C8 position. The perchlorate counter anion is coordinated to the silver atom through one of its oxygen atoms and the perchlorate anion coordinated to Ag2 is disordered over two positions. Each silver atom also has an acetone coordinated through the carbonyl oxygen acting as an auxiliary ligand. The Ag···Ag separation across ligand 3.14a is approximately 9 Å.

Ligand 3.14a chelates to two silver atoms through an alkene of the allyl ether arm and through the naphthalene ring at the C7,C8 position. This chelation has a significant effect on the dihedral angle between the two naphthalene rings as seen in Figure 3.34.

The acute torsion angle in the free ligand 3.14b is between the two ends of the naphthalene ring containing the allyl ether substituents whereas in the complex the acute angle is between a substituted and unsubstituted end. The torsion angle between the naphthyl rings changes from 68.9 º in the free ligand to approximately 110 º in the coordinated ligand. This change in angles occurs to accommodate the chelation of ligand

a) b)

Figure 3.34 – Comparison of the torsion angle between the naphthalene

rings in ligand 3.14. a) View of the coordinated ligand looking down the transannular bond b) view of the free ligand 3.14b also looking down the transannular bond.

Again, the η2 coordination occurs on a predicted position on the naphthalene ring and in this case the C7,C8 position. As in the previous examples of coordination at a localised double bond, it leads to elongation, however due to the poor refinement there are large error values on bond lengths within the structure and a definitive comparison cannot be made.

Within the crystal packing there is alternating staggered, then edge-to-face π-π stacking interactions. There is also weak hydrogen bonding interactions between the hydrogen atoms on 3.14a and the perchlorate oxygen atoms. The chloroform molecule is held in place by weak hydrogen bonding between its hydrogen and an oxygen atom from a perchlorate as well as between the chlorine atoms and a hydrogen on a coordinated acetone.

The enantiomerically pure 3.14b and silver(I) perchlorate was also successfully reacted together under the same conditions as the racemic ligands. Again the crystalline product,

3.24, was analyzed by X-ray diffraction and this time the structure solved in the

monoclinic chiral space group C2. The basic ligand/silver motif of this complex is the same as in 3.23. The structure is a discrete M2L complex with each ligand chelating to

two silver atoms via an alkene on an allyl ether arm and an η2 coordination at the C7,C8 position on the naphthalene ring.

Figure 3.35 – View of the core structure of complex 3.24.

The differences between 3.23 and 3.24 lie in the position of the counter anions and