Self-Assembly of Heterometallic Metallomacrocycles via Ditopic

Article pubs.acs.org/Organometallics

Self-Assembly of Heterometallic Metallomacrocycles via Ditopic Fluoroaryl Gold(I) Organometallic Metalloligands Montserrat Ferrer,*,† Albert Gutiérrez,† Laura Rodríguez,† Oriol Rossell,† Eliseo Ruiz,†,∥ Marianne Engeser,*,‡ Yvonne Lorenz,‡ Reinhold Schilling,‡ Pilar Gómez-Sal,§ and Avelino Martín§ †

Departament de Química Inorgànica, Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain Kekulé-Institut für Organische Chemie und Biochemie der Universität, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany § Departamento de Química Inorgánica, Campus Universitario-Edificio de Farmacia, Universidad de Alcalá, 28871 Alcalá de Henares, Spain ∥ Institut de Recerca en Química Teòrica i Computacional, Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain ‡

S Supporting Information *

ABSTRACT: A series of heterometallic metallamacrocycles have been constructed from self-assembly reactions between the fluorinated Au(I) organometallic compounds [(AuC6F4py)2(μ2-diphosphane)] [diphosphane = bis(diphenylphosphanyl)methane (dppm) (1), 1,2-bis(diphenylphosphanyl)ethane (dppe) (2), trans-1,2-bis(diphenylphosphanyl)ethylene (dppet) (3), 1,3-bis(diphenylphosphanyl)propane (dppp) (4), 1,4-bis(diphenylphosphanyl)butane (dppb) (5), and 4,4′-bis(diphenylphosphanyl)-1,1′-biphenyl (dppdph) (6)] and the cis-blocked complexes [M(P−P)(H2O)2](OTf)2 (M = Pd) (P−P = dppp, dppf) (a,c), (M = Pt) (P−P = dppp, dppf) (b,d). Changes of the backbone of the diphosphanes were seen to have an influence on the resulting species. While the self-assembly reactions involving [(AuC6F4py)2(μ2-dppm)] (1), [(AuC6F4py)2(μ2dppb)] (5), and [(AuC6F4py)2(μ2-dppdph)] (6) donors gave exclusively [2 + 2] heterometallomacrocycles, the assemblies arising from [(AuC6F4py)2(μ2-dppe)] (2) as well as the combinations between [(AuC6F4py)2(μ2-dppp)] (4) and [M(dppp)(H2O)2](OTf)2 (a, b) and [(AuC6F4py)2(μ2-dppet)] (3) and [M(dppf)(H2O)2](OTf)2 (c, d) consisted of an equilibrium between two macrocyclic species ([2 + 2] and a higher-order aggregate [3 + 3], [4 + 4],...). Multinuclear (1H, 19 F, 31P) and diffusion NMR spectroscopy in combination with a complete set of ESI-FT-ICR mass spectrometry experiments were used to elucidate the nature of the different assemblies. DFT calculations were performed in order to calculate the molecular geometry and estimate the relative stability of different conformations of [2 + 2], [3 + 3], and [4 + 4] supramolecular species for two of the used diphosphanes.

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INTRODUCTION Self-assembly reactions have represented a breakthrough in obtaining novel and surprising supramolecular metallomacrocyclic species with interesting applications in catalysis, sensoring, biomimetics, etc.1−11 In these processes, the choice and rational design of appropriate building blocks are crucial to obtain a particular metallomacrocycle with specific characteristics that can be the responsible of determined properties. In particular, the organic backbone of the ligands and the nature of the metal−ligand interaction usually control the structure, conformation, and topology of the final supramolecules. Although an important number of metallomacrocycles has been reported,1−9,12−15 the vast majority of them correspond to homometallic species that have been obtained by self-assembly © 2012 American Chemical Society

reactions between one specific organic ligand and a unique metal acceptor unit. Recently, increasing interest has been paid to heterometallic metallomacrocycles16−25 because they are based on the precise positioning of at least two different metal centers within a cyclic architecture. The introduction of different metals in the assemblies expands their potential applications due to the varied properties i.e. redox,8,17,26,27 luminescence,8,17,26 etc., together with the possibility of the existence of cooperative effects in processes such as catalysis or molecular recognition.28−30 Special Issue: Fluorine in Organometallic Chemistry Received: November 7, 2011 Published: January 25, 2012 1533

dx.doi.org/10.1021/om201028q | Organometallics 2012, 31, 1533−1545

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Scheme 1

introduction of phosphanes allowed us to obtain a series of flexible polytopic species suitable for coordination to acidic metal centers. With the aim of developing heterometallic supramolecular architectures with diverse sizes and/or topologies, we have carried out a systematic study of the self-assembly reactions between the designed by us gold(I) metalloligands [(AuC6F4py)2(μ2-diphosphane)] (1−6), which bear diphosphanes with carbon chains of different length and flexibility, and the cis-blocked square planar [M(P−P)(H2O)2]2+ (M = Pd, Pt) (P−P = dppp, dppf) (a−d). At this point, it is important to notice that, in general, nonrigid “spacers” are relatively less predictable in self-assembly and may generate a variety of flexible assemblies in which the bridging ligands could adapt to a thermodynamically stable conformation that provides “breathing ability” in the solid state and adaptive recognition properties.24,39,42−45 Additionally, the establishment of the relatively strong aurophilic attractions, commonly found in gold compounds, could have an influence on the “unpredictable” result of the self-assembly reaction as it has been described for other phosphane gold(I) complexes.46−49

In contrast to homometallic species, heterometallic supramolecular assemblies remain relatively scarce given that their preparation is usually more complex because it requires a stepwise approach involving the previous synthesis of building blocks with metals inside or metalloligands. In particular, organometallic ligands as building blocks to link other metal ions have proved to be ideal candidates for hierarchical assembly into heterometallic supramolecular architectures.16,24,31,32 Our interest in organometallic fluorine chemistry stems from early work concerning the self-assembly of homometallic triangular and square metallomacrocycles containing tetrafluorophenylene pyridyl ligands (1,4-bis(pyridyl)tetrafluorobenzene and 4,4′-bis(4-pyridyl)octafluorobiphenyl) and PdII or PtII corners.33−35 Substitution of ring hydrogens by fluorines in aromatic compounds results in dramatic differences in properties, in particular, the introduction of strongly electron-withdrawing fluorine atoms at strategic points in a molecular structure might be expected to tune electronic properties as electron deficiency of the macrocyclic cavity.36−39 As an extension of our studies on fluorinated derivatives, we have recently described40 the synthesis of a series of gold(I) fluorinated organometallic compounds with terminal pyridine groups, specifically designed to generate heterometallic macrocycles by applying the named “complex-as-ligand” approach.17,19,20,41 This strategy is based on the formation of a kinetically inert complex of a metal ion with free binding sites followed by the formation of metallosupramolecular macrocycles through coordination of the latter to a kinetically labile metal complex. Although rigid linear fluorinated aurates seemed not to fulfill our expectations, the

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RESULTS AND DISCUSSION Synthesis and Characterization of Heterometallic Assemblies. As shown in Scheme 1, square-planar acceptor compounds [M(P−P)(H2O)2](OTf)2 (M = Pd, Pt) (P−P = dppp, dppf) (a−d) were treated separately with the flexible ditopic donors [(AuC6F4py)2(μ2-diphosphane)] [diphosphane = bis(diphenylphosphanyl)methane (dppm) (1), 1,2-bis(diphenylphosphanyl)ethane (dppe) (2), trans-1,2-bis(diphenylphosphanyl) ethylene (dppet) (3), 1,3-bis(diphenylphosphanyl)propane (dppp) (4), 1534


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1,4-bis(diphenylphosphanyl)butane (dppb) (5), and 4,4′bis(diphenylphosphanyl)-1,1′-biphenyl (dppdph) (6)] in 1:1 molar ratio in dichloromethane at room temperature. The formation of new symmetric aggregates was initially characterized by recording the 31P{1H} NMR spectra of the reaction solutions, which showed a gold bound phosphane broad singlet or triplet resonance and a singlet associated to palladium or platinum bound phosphane, respectively (for representative examples see Figure 1).

Figure 2. 1H NMR spectra (CDCl3, 298 K) of the species obtained from the 1:1 self-assemblies of c+5 (top) and a+2 (bottom). Asterisks indicate the resonances of a higher nuclearity assembly.

suggest the presence of two highly symmetric constituents in the reaction mixture that were assigned to a [2 + 2] metallomacrocycles (a2)2 and a higher nuclearity species (a2)>2 (tentatively [3 + 3] or [4 + 4]), on the basis of a combination of NMR, mass-spectrometric studies (ESI-FT-ICR), molecular modeling, and X-ray data.50 Spectroscopic evidence of the relative sizes of both self-assembled species of the mixture indicated above (a+2) has been extracted from 1H DOSY NMR spectroscopic experiments. The resonances at δ = 9.06 and 9.00 ppm allowed us to distinguish between the largest (a2)>2 (diffusion coefficient = 2.75 × 10−10 m2 s−1) and the smallest (a2)2 (diffusion coefficient = 3.31 × 10−10 m2 s−1) components (Figure 3).

Figure 1. 31P{1H} NMR spectra (CDCl3, 298 K) of assemblies c+6 (top) and b+6 (bottom).

The P−Pd and P−Pt peaks are upfield shifted by more than 5 ppm compared with starting products, and in addition, platinum compounds present 1J(Pt−P) that are by roughly 700 Hz smaller than those of the starting [Pt(P−P)(H2O)2](OTf)2 (b, d), clearly indicating the ligand-to-metal electron donation and thus the coordination of the metalloligands to either palladium or platinum ions. The P−Au peaks do not show significant shift variations in comparison with the organometallic gold(I) precursors because the phosphorus centers are far away from the point where coordination takes place. After the reaction completion (ca. 2 h), the species were obtained as solids by precipitation with hexane in good yields (70−90%) and further characterized. As expected, the 1H NMR spectra showed a downfield shift of the α-pyridine protons due to the coordination of the pyridine rings to the metal center. Surprisingly, however, the 1H NMR spectra of the assemblies arising from [M(P−P)(H2O)2](OTf)2 (a−d) + [(AuC6F4py)2 (μ2-dppe)] (2) together with the combinations [M(dppp)(H2O)2](OTf)2 (a, b) + [(AuC6F4py)2(μ2-dppp)] (4) and [M(dppf)(H2O)2](OTf)2 (c, d) + [(AuC6F4py)2(μ2-dppet)] (2) displayed either a broad or two very close α-pyridine signals, in contrast to the unique sharp peak observed for the rest of self-assembled compounds and expected for a discrete structure (see Figure 2 for representative examples). It is important to remark that, α-pyridine protons occur in an area of the 1H NMR spectra that is free of other overlapping peaks and provide information on the number of components formed in the self-assembly process. For example, the two signals of comparable intensity around δ = 9.0 ppm in the 1H NMR spectrum of [Pd(dppp)(H2O)2](OTf)2 (a) + [(AuC6F4py)2(μ2-dppe)] (2) (Figure 2, bottom)

Figure 3. Section of 1H DOSY spectrum (CDCl3, 298 K) of a 1:1 mixture of a+2.

Unfortunately, however, the flexibility of the donor, and consequently its unpredictable conformation, precluded an estimation of the size of the metallomacrocycles from the evaluation of hydrodynamic radii values that could give us a clue about the nuclearity of the aggregates present in the equilibrium. 1535


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Because of their simplicity, 19F NMR spectra provided further evidence of the number and relative size of the selfassembled species. When only one metallomacrocycle is detected by 1H NMR, 19F NMR spectra display two different multiplets around −115 and −145 ppm, respectively, that correspond to the ortho- and meta- fluorine atoms of tetrafluorophenylene units bonded to the gold(I) center (see top of Figure 4 for a representative example).

Mass Spectrometry Experiments. To unambiguously assign the major resonances in the NMR, mass spectrometric studies were carried out with soft electrospray ionization (ESI) and a high-resolution mass spectrometer (FT-ICR). The experiments were performed in an acetone solution of the corresponding macrocycles. Because of the huge quantity of obtained data, relevant signals for all compounds are given in Table 1. Representative examples are shown in Figure 6. As can be seen, all the assemblies present peak series that prove the formation of [2 + 2] self-assembled metallomacrocycles as the main species. The latter are detected as doubly, triply, or even quadruply charged ions formed by loss of two, three or four triflate anions, respectively. As a result, the [2 + 2] aggregate correspond to the smaller component in case of equilibria (a−d) + [(AuC6F4py)2(μ2-dppe)] (2) and combinations [M(dppp)(H2O)2](OTf)2 (a, b) + [(AuC6F4py)2(μ2-dppp)] (4) and [M(dppf)(H2O)2](OTf)2 (c, d) + [(AuC6F4py)2(μ2dppet)] (2), and is the single metallomacrocycle formed when only one assembly is detected by both 1H and 19FF NMR spectroscopies, i.e., (a−d) + [(AuC6F4py)2(μ2-dppm)] (1), (a, b) + [(AuC6F4py)2(μ2-dppet)] (3), (c, d) + [(AuC6F4py)2 (μ2-dppp)] (4), (a−d) + [(AuC6F4py)2(μ2-dppb)] (5), and (a−d) + [(AuC6F4py)2(μ2-dppdph)] (6) (see Scheme 1). Although the composition of the most common metallomacrocycle was unambiguously determined, the nature of the second species should be addressed. Remarkably, ESI spectra are quite similar for all compounds described here and even though NMR results indicate the presence of two different sized assemblies (e.g., b+4, Figure 6b), its ESI mass spectra do not differ significantly from the ones for which only one species is visible in the NMR spectra (see representative spectrum in figure 6a). An inspection of Figure 6a shows that in addition to the peaks due to [2 + 2] metallocycle, two additional signals seem noteworthy; they correspond to triply charged [4 + 4] and quadruply charged [6 + 6] aggregates, whose abundance steadily diminishes with aggregate size. In this case, other aggregate sizes are not observed in significant amounts. Thus, the appearance of the ESI spectra suggests the presence of [2 + 2] species in solution that form nonspecific dimers and trimers upon ESI, a phenomenon typical for ESI at higher concentrations and soft ionization conditions. The spectrum in Figure 6b (b+4) contains some more signals for ions containing only one Pt atom. Ion abundances for these are minimized at softest ionization conditions and increase when the instrument is tuned to harsher conditions. These ions, including the almost ubiquitous [1 + 1] species, are thus ascribed to partial fragmentation in the higher pressure region of the ESI source, which we unfortunately were not able to avoid completely for most of the substances described here. Further, this spectrum shows noticeable abundances of [3 + 3] aggregates (Figure 6b and Supporting Information Figure S1). The presence of these is at least in part due to in-source fragmentation as well, because gas-phase fragmentation of the [4 + 4] species leads to [1 + 1] and [3 + 3] compounds as proved by the MS/MS experiments described below. Ion abundances of the [3 + 3] species are most intense when other in-source fragmentation products are observed as well, and they are not significantly increased in the spectra of compounds that show two sets of signals in the NMR (Table 1). Nevertheless, the presence of some small amounts of [3 + 3] species in solution could not be discarded. To obtain more information on the systems and clarify the nature of the observed [4 + 4] species, mixing experiments have

Figure 4. 19F NMR spectra (CDCl3, 298 K) of the species obtained from the 1:1 self-assemblies of c+5 (top) and a+2 (bottom). Asterisks indicate the resonances of a higher nuclearity assembly.

While Fortho appears slightly shifted to higher fields in comparison with starting products, no significant shifting is observed for Fmeta on coordination. Indeed, when two assemblies coexist in equilibrium, two separate pairs of fluorine resonances are clearly seen (Figure 4, bottom) and allowed to carry out a study of the concentration dependence of the equilibrium composition by 19F NMR spectroscopic analysis. As shown by a series of spectra for the mixture [Pt(dppp)(H2O)2](OTf)2 (b) + [(AuC6F4py)2(μ2-dppp)] (4) (Figure 5),

Figure 5. 19F NMR spectra (CDCl3, 298 K) of the species obtained from the 1:1 self-assembly of b+4 at different concentrations ranging between 30 and 10 mM. Asterisks indicate the resonances of a higher nuclearity assembly.

the intensity of the inner pair of peaks decreases monotonously on lowering the concentration of the solution. This feature reflects a pronounced entropic control over the equilibrium and confirms that the outer and inner pairs of 19F NMR resonances are due to the smaller and larger species, respectively. 1536


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Table 1. Relevant ESI-MS Signals from All the Obtained Species metals and ligands

assemblies

ESI-FT-ICR peaks

PddpppAudppm PtdpppAudppm PddpppfAudppm PtdppfAudppm PddpppAudppe PtdpppAudppe PddppfAudppe PtdppfAudppe PddpppAudppet PtdpppAudppet PddppfAudppet PtdppfAudppet PddpppAudppp PtdpppAudppp PddppfAudppp PtdppfAudppp PddpppAudppb PtdpppAudppb PddppfAudppb PtdppfAudppb PddpppAudppdph PtdpppAudppdph PddppfAudppdph PtdppfAudppdph

a+1 b+1 c+1 d+1 a+2 b+2 c+2 d+2 a+3 b+3 c+3 d+3 a+4 b+4 c+4 d+4 a+5 b+5 c+5 d+5 a+6 b+6 c+6 d+6

[(a1)-OTf]+, [(a1)-2OTf]2+, [(a1)2-2OTf]2+, [(a1)2-3OTf]3+, [(a1)3-2OTf]2+, [(a1)4-3OTf]3+ [(b1)-2OTf]2+, [(b1)2-2OTf]2+, [(b1)2-3OTf]3+, [(b1)2-4OTf]4+, [(b1)3-2OTf]2+, [(b1)4-3OTf]3+, [(b1)6-4OTf]4+ [(c1)-OTf]+, [(c1)-2OTf]2+, [(c1)2-2OTf]2+, [(c1)3-2OTf]2+, [(c1)4-3OTf]3+ [(d1)-OTf]+, [(d1)-2OTf]2+, [(d1)2-2OTf]2+, [(d1)2-3OTf]3+, [(d1)2-4OTf]4+, [(d1)4-3OTf]3+ [(a2)-OTf]+, [(a2)-2OTf]2+, [(a2)2-2OTf]2+, [(a2)3-2OTf]2+, [(a2)4-3OTf]3+, [(a2)6-4OTf]4+ [(b2)-2OTf]2+, [(b2)2-2OTf]2+, [(b2)2-3OTf]3+, [(b2)3-2OTf]2+, [(b2)4-3OTf]3+ [(c2)-OTf]+, [(c2)-2OTf]2+, [(c2)2-2OTf]2+, [(c2)3-2OTf]2+, [(c2)4-3OTf]3+ [(d2)-2OTf]2+, [(d2)2-2OTf]2+, [(d2)2-3OTf]3+, [(d2)3-2OTf]2+, [(d2)4-3OTf]3+ [(a3)-OTf]+, [(a3)2-2OTf]2+, [(a3)4-3OTf]3+ [(b3)-OTf]+, [(b3)2-OTf]+, [(b3)2-2OTf]2+, [(b3)2-3OTf]3+, [(b3)3-2OTf]2+, [(b3)4-3OTf]3+ [(c3)-OTf]+, [(c3)2-2OTf]2+, [(c3)4-3OTf]3+ [(d3)-OTf]+, [(d3)-2OTf]2+, [(d3)2-2OTf]2+, [(d3)2-3OTf]3+, [(d3)2-4OTf]4+, [(d3)3-2OTf]2+, [(d3)4-3OTf]3+ [(a4)-OTf]+, [(a4)-2OTf]2+, [(a4)2-2OTf]2+, [(a4)2-3OTf]3+, [(a4)3-2OTf]2+, [(a4)4-3OTf]3+, [(a4)6-4OTf]4+ [(b4)-2OTf]2+, [(b4)2-2OTf]2+, [(b4)2-3OTf]3+, [(b4)3-2OTf]2+, [(b4)4-3OTf]3+, [(b4)6-4OTf]4+ [(c4)-OTf]+, [(c4)-2OTf]2+, [(c4)2-2OTf]2+, [(c4)2-3OTf]3+, [(c4)3-2OTf]2+, [(c4)4-3OTf]3+ [(d4)-OTf]+, [(d4)-2OTf]2+, [(d4)2-2OTf]2+, [(d4)2-3OTf]3+, [(d4)2-4OTf]4+, [(d4)4-3OTf]3+ [(a5)-2OTf]2+, [(a5)2-2OTf]2+, [(a5)2-3OTf]3+, [(a5)2-4OTf]4+, [(a5)3-2OTf]2+, [(a5)4-3OTf]3+, [(a5)6-4OTf]4+ [(b5)2-2OTf]2+, [(b5)2-3OTf]3+, [(b5)2-4OTf]4+, [(b5)3-2OTf]2+, [(b5)4-3OTf]3+, [(b5)6-4OTf]4+ [(c5)-OTf]+, [(c5)-2OTf]2+, [(c5)2-2OTf]2+, [(c5)2-3OTf]3+, [(c5)2-4OTf]4+, [(c5)3-2OTf]2+, [(c5)4-3OTf]3+, [(c5)6-4OTf]4+ [(d5)2-2OTf]2+, [(d5)2-3OTf]3+, [(d5)4-3OTf]3+ [(a6)-OTf]+, [(a6)2-2OTf]2+, [(a6)4-3OTf]3+, [(a6)6-4OTf]4+ [(b6)2-2OTf]2+, [(b6)2-3OTf]3+, [(b6)2-4OTf]4+ [(c6)-OTf]+, [(c6)-2OTf]2+, [(c6)2-2OTf]2+, [(c6)2-3OTf]3+, [(c6)2-4OTf]4+, [(c6)4-3OTf]3+, [(c6)4-4OTf]4+ [(d6)2-2OTf]2+, [(d6)2-3OTf]3+, [(d6)2-4OTf]4+, [(d6)4-3OTf]3+, [(d6)4-4OTf]4+

Figure 6. ESI FT-ICR mass spectra of compounds obtained from 1:1 mixtures of b+1 (a) and b+4 (b). Minor amounts of chlorine-containing ions are probably due to chloride salt residues present in the inlet system of the mass spectrometer. See Supporting Information Figure S1 for enlargements of isotope patterns.*: m/z 1293.5: [(b4)2-3OTf]3+, (dppp)2Pt2(L)2(OTf)3+.

been performed. Two samples at a time were mixed in solution, and the exchange behavior was monitored by recording ESI mass spectra after various periods of time. Figure 7 shows the spectra obtained for a mixture of b+2 and b+5. The kinetics observed for the [2 + 2] species is quite slow; it takes 30 min at

room temperature to detect clearly visible amounts of the mixed species with two different gold metalloligands connecting two Ptdppp entities and it takes several days to reach thermodynamic equilibrium. Accordingly, this is the time scale of breaking and reconnecting bonds between Pt and the linkers 1537


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Figure 7. ESI-FTICR mass spectra of a 1:1 mixture of b+2 and b+5 measured at the marked times after combining the solutions. The two spectra at the top belong to the pure samples before the experiment. (a) Enlarged m/z region of the doubly charged [2 + 2] aggregate; the newly appearing signal belongs to the mixed [2 + 1 + 1] species containing two Pt(dppp) units (b), one dppe (2), and one dppb (5) linker; (b) enlarged m/z region of the triply charged [4 + 4] species; the signal at m/z 2736 is the [4 + 2 + 2] ion with four Pt(dppp) units, two dppe and two dppb linkers.

with pyridine end, because the mixed [2 + 1 + 1] species can only be formed by cleavage and reformation of two of these. Notably, the region of the [4 + 4] species of the very same spectra is highly informative, a new signal of approximately double intensity arose immediately after mixing. It appears exactly in the middle between the two unmixed species and is assigned to a [4 + 2 + 2] species consisting of four Ptdppp moieties and two units of metalloligands 2 and 5, respectively. Statistical equilibration including the formation of [4 + 1 + 3] and [4 + 3 + 1] species only appears after much longer mixing periods and needs approximately the same time as described above for the ligand exchange in [2 + 2] species. This behavior is only explained by a very fast exchange of intact [2 + 2] subunits, which subsequently undergo much slower ligand exchange by opening and reforming the Pt−pyridine bond. The [4 + 4] aggregate detected in the gas phase thus consists of two [2 + 2] subunits that are very weakly bound and easily exchanged. Similar mixing experiments were performed with the platinum derivatives b+2/d+2, and the observed behavior was similar to that described above. For the Pd substances, the mixtures a+2/a+5 and a+4/c+4 were tested. Complete equilibration occurred already after 5 min for both [2 + 2] and [4 + 4] species. Obviously, ligand exchange is much faster for Pd− pyridine compared to Pt−pyridine bonds, in accordance to literature,51 and is too fast to allow noticing of kinetic differences by the chosen method. Astonishingly, neither mixing experiments nor ESI spectra show indications of the presence in solution (at least at reasonable concentrations) of other species that the [2 + 2] aggregates. The ESI spectra for species that present additional sets of signals in the NMR do not display any significant differences from those with only one set of signals. The discrepancy between NMR and ESI results may be found in the choice of the solvent, i.e., whereas all ESI spectra have been taken by spraying from acetone, CH2Cl2 and CHCl3 were used in NMR studies. Unfortunately, all our attempts to obtain stable electrospray conditions and detect intact aggregates were unsuccessful when using CHCl3 or CH2Cl2. Another common method for structure elucidation by mass spectrometry involves induced fragmentation of the species of interest in the gas phase. It is often used as a tool to study the structure of covalent ions in a mass spectrometer.52

The method was also proposed and successfully employed to study and distinguish supramolecular aggregates53,54 like rotaxanes,55 capsules,56 and metallosupramolecular squares.57,58 Thus, we decided to fragment the [4 + 4] ions detected in the ESI spectra. The aim was to decide whether their structure was a mere nonspecific dimer of two [2 + 2] complexes, i.e., a sandwich of two [2 + 2] assemblies, as indicated both by the mixing experiments and the overall appearance of the ESI spectra, or a [4 + 4] macrocycle present already in solution in accordance with NMR. Infrared multiphoton dissociation (IRMPD) was chosen as fragmentation method. As a starting point, the more abundant [2 + 2] complex was fragmented (see Figure 8 for substance b+3; similar results have been obtained for b+1, d+1, and d+3). At first glance, this metallosupramolecular ion seemed to be astonishingly stable as no new signals appeared at short laser irradiation times. But a closer look on the isotope pattern revealed that the doubly charged [2 + 2] ion does indeed fragment very easily, yielding two singly charged [1 + 1] ions with the same m/z ratio. At longer irradiation times, the [1 + 1] species further fragment by breaking the weakest bond, which is the metal−pyridine bond. The resulting diphosphane metal complex [M(P−P)(OTf)]+ finally loses the anion in its protonated form, as has previously been described in the literature.58 Typically, low energy fragmentation methods like IRMPD induce the cleavage of the weakest bond in the mother ion. Therefore, the fragmentation of a [4 + 4] macrocycle should be significantly different from that of a nonspecific dimer of [2 + 2] aggregates, which is expected to split symmetrically into two [2 + 2] halves. In contrast, the experiment shows an unsymmetrical cleavage into one [3 + 3] and one [1 + 1] species (Figure 8b). A similar unsymmetrical formation of trimer and monomer has been previously observed for metallosupramolecular squares and has been interpreted mechanistically by the preferred back-side attack of one ligand at the third metal in the initially formed open-chain [4 + 4] intermediate.58 Accordingly, the IRMPD fragmentation results could be interpreted analogously as an indication for the presence of intact [4 + 4] macrocycles in the gas phase. This result, however, is contradictory to the above interpretation of the mixing experiments and the overall appearance of the ESI spectra, which indicate that the [4 + 4] species observed 1538


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Figure 8. IRMPD MS/MS spectra of the species obtained from the 1:1 self-assembly of b+3. (a) Mass selection of the doubly charged [2 + 2] species (top) and spectra after increasing laser irradiation times, the insets show the enlarged isotope pattern; (b) IRMPD MS/MS spectrum of the triply charged [4 + 4] species after 0.3 s laser irradiation. *: electronic noise.

extraction of the following conclusions: (a) the folded structures of (b2)2 and (b5)2 correspond to the most stable systems. As can be seen in Figure 9 and Supporting Information Figure S4, the calculated structures for the folded [2 + 2] heteromacrocycles are very close to that established by X-ray diffraction studies for the analogous (c5)2 and (d5)2 systems (see Figures S2 and S3 in Supporting Information); (b) in general, a decrease of the stability of the aggregate on increasing its nuclearity is found. This fact suggests that the unknown component in equilibria with [2 + 2] metallomacrocycles is likely to be a [3 + 3] aggregate although a [4 + 4] species cannot totally be ruled out. Remarkably, the square [4 + 4] results to be more stable than the folded [3 + 3] aggregate within the b+5 family; (c) in each family, the comparison between the three larger [4 + 4] systems, folded, square, and catenane structures, indicates that the square open structure is the most stable. This difference in energies is more important for b+5 assemblies; (d) open [3 + 3] and [4 + 4] aggregates show a significant stabilization in comparison to the folded in the case of the b+5 system. This trend is not observed for b+2 compounds and could be related to an increase of length and flexibility of the carbon chain of the diphosphane on going from 2 (dppe) to 5 (dppb); (e) the energy differences between the most stable structures, i.e., the folded (b2)2 and (b5)2, and the bigger calculated systems do not show a general trend that could account for the fact that while NMR spectra of b+5 display a pattern indicative of the presence of [2 + 2] metallomacrocycle exclusively, a mixture of the latter and a larger species is detected for b+2.

in the gas phase are noncovalent nonspecific assemblies of [2 + 2] aggregates. This discrepancy might be solved by considering that the sandwich aggregate of two [2 + 2] species is most probably held together electrostatically by intercalated anions. The stability of this anion-bridged aggregate in the gas phase is much higher than the corresponding solvated structure in solution and, therefore, the sandwich structure does not necessarily break into two symmetrical halves upon IRMPD in the gas phase but rearranges to yield the observed unsymmetrical fragmentation. For covalently bound ions, rearrangements before dissociation are observed quite often, especially in low-energy fragmentation methods like IRMPD, and are a known complication for structure elucidation.52,59 Yet, they were not expected to compete efficiently in noncovalently bound supramolecular aggregates. Indeed, this is, to the best of our knowledge, the first published example in which IRMPD is misleading in structure assignments of supramolecular compounds. Therefore, the combination of ESI experiments reported here did not allow us to determine the nature of the unknown high nuclearity species detected by NMR spectroscopy in some assemblies. Theoretical Study. Because ESI experiments did not allow us to determine the nature of the unknown high nuclearity species that appear in NMR spectra, we decided to undertake a theoretical study. To evaluate the stability of the different heterometallic assemblies, DFT calculations were carried out using the numerical Siesta computer code (see Computational Details). Full optimizations were performed for six different structures corresponding to the assemblies b+2 ([Pt(dppp)(H2O)2](OTf)2 + [(AuC6F4py)2(μ2-dppe)]) and b+5 ([Pt(dppp)(H2O)2](OTf)2 + [(AuC6F4py)2(μ2-dppb)]) for which two and one assemblies are detected by NMR, respectively. The considered structures (see Figure 9) correspond to a folded (b2)2, square (b2)2, folded (b2)3, triangle (b2)3, folded (b2)4, square (b2)4, and a catenane (b2)4 (the corresponding structures of the b+5 family of heterometallomacrocycles are represented in Supporting Information Figure S4). The calculated relative energies for these structures are collected in Table 2. The analysis of the obtained values allows

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CONCLUSIONS The foregoing results illustrate that flexible gold(I) metalloligands of the type [(AuC6F4py)2(μ2-diphosphane)] react with cis-blocked palladium or platinum compounds to form discrete self-assembled heterometallomacrocycles in good yields. A combination of ESI mass spectrometry, theoretical DFT calculations, and X-ray diffraction studies strongly supports the formation of [2 + 2] metallocycle as the predominant species. Solution studies by 19F and 1H NMR spectroscopy as well as DOSY experiments revealed that, for some assemblies, the [2 + 2] species are in dynamic equilibrium with a larger aggregate (likely to be the [3 + 3] 1539


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Figure 9. Representations of the DFT optimized structures corresponding to the b2 heterometallomacrocycles. (color codes: Au, magenta; Pt, green; P, pale-orange; F, yellow; N, blue). All hydrogen atoms have been omitted for clarity.

compounds behave similarly under ESI conditions. Higher nuclearity aggregates are formed during ESI that probably correspond to electrostatically hold species. Fragmentation of these noncovalently bound [2 + 2]2 (i.e., [4 + 4]) species includes rearrangement to [3 + 3] ions and thus is misleading when used for structure determination. In addition to their synthesis and characterization, it is important to remark that the supramolecules reported here present specific features, i.e., the presence of fluorinated rings, the coexistence of different metals (in particular gold centers), as well as the possibility of adopting diverse conformations and generating cavities of different shapes and/or size. All these characteristics make them candidates to interact by different ways with a wide range of compounds. Further work will focus on the development of this potentiality and on the study of the capacity of these macrocyclic architectures in molecular recognition.

Table 2. Relative Calculated Energies (in kcal/mol per [(dppp)2Pt2(L)2]4+ unit, L = Gold Metalloligand) Using the Siesta Code with the DRSLL Functional for the Six Different Heterometallic Assemblies Corresponding to b+2 and b+5 Assemblies (See Figure 9 and Supporting Information Figure S4) assembly

b+2

b+5

folded [2 + 2] square [2 + 2] folded [3 + 3] triangle [3 + 3] folded [4 + 4] square [4 + 4] catenane [4 + 4]

0.0 21.5 63.0 65.9 110.4 107.1 132.7

0.0 23.9 92.6 53.3 108.9 84.3 107.8

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metallocycle from DFT calculations). Unfortunately, however, the whole of experimental and theoretical results have not allowed us yet to find a straightforward relation between the characteristics of the diphosphanes and the number of species in solution. Detailed mass spectrometric studies, including mixing experiments and IRMPD, have demonstrated that, in spite of the NMR experiments reported above, all the synthesized

EXPERIMENTAL SECTION

All manipulations were performed under prepurified N2 using standard Schlenk techniques. All solvents were distilled from appropriate drying agents. Infrared spectra were recorded on an FT-IR 5700 Nicolet spectrophotometer. 31P{1H} NMR (δ(85% H3PO4) = 0.0 ppm), 19F NMR (δ(CFCl3) = 0.0 ppm), and 1H NMR (δ(TMS) = 0.0 ppm) spectra were obtained on a Bruker DXR 250, Varian-Unity 300, 1540


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Varian-Inova 300, and Varian Mercury 400 spectrometers. Elemental ́ i analyses of C, H, N, and S were carried out at the Centre Cientific Tecnològic de la Universitat de Barcelona (CCiTUB).60 Mass Spectrometry. ESI-FT-ICR mass spectra were recorded with an APEX IV Fourier-transform ion cyclotron resonance (FTICR) mass spectrometer (Bruker Daltonics, Bremen) equipped with a 7.05 T magnet and an Apollo ESI source. Samples were dissolved in acetone (0.1 mM) and introduced via a syringe pump with a flow rate of 200 mL/h. Nitrogen was used as nebulizing and drying gas. Drying gas temperature was held at RT. Nebulizing and drying gas flows, capillary exit, and skimmer voltages and hexapol accumulation times were readjusted for each sample to obtain very soft ionization conditions and minimize fragmentation during the ESI process. For each measurement, 16−500 scans were averaged to improve the signal-to-noise ratio. For infrared multiphoton dissociation (IRMPD) MS/MS spectra, mass-selection of the whole isotopic pattern was followed by irradiation with a CO2 IR laser at a wavelength of 10.6 μm and a power of max 25 W. Although not shown in each case here, a series of measurements with different irradiation times was recorded for every parent ion to monitor the fragmentation kinetics. Computational Details. Full optimizations of the studied complexes were performed by means of density functional theory61 calculations using the Siesta code.62,63 For such calculations, the DRSLL functional,64 which was especially designed for weak interactions, was employed because it provides a better agreement with the available experimental crystal structure than other functionals such as the PBE one.65 The PBE functional predict higher stability for the open square structure (b5)2 than the folded structure in disagreement with the experimental crystal structure while the DRSLL functional gives the right answer. Only valence electrons are included in the calculations, with the core being replaced by norm-conserving scalar relativistic pseudopotentials factorized in the Kleinman− Bylander form.66 The pseudopotentials are generated according to the method proposed by Trouiller and Martins.67 Using the following cutoff radii for the s, p, d and f shells: Au (6s1 r = 2.30, 6p0 r = 2.30, 5d10 r = 1.80, 5f0 r = 2.30), Pt (6s1 r = 2.32, 6p0 r = 2.47, 5d9 r = 1.23, 5f0 r = 2.32), P (3s2 r = 1.85, 3p4 r = 1.85, 3d0 r = 1.85, 4f0 r = 1.85), F (2s2 r = 1.20, 2p5 r = 1.20, 3d0 r = 1.20, 4f0 r = 1.20), N (2s2 r = 1.14, 2p3 r = 1.14, 3d0 r = 1.14, 4f0 r = 1.14), C (2s2 r = 1.25, 2p2 r = 1.25, 3d0 r = 1.25, 4f0 r = 1.25) and H (1s1 r = 1.14, 2p0 r = 1.14, 3d0 r = 1.14, 4f0 r = 1.14). As basis set, a double-ζ with polarization was employed for the P, F, N, C, and H, while for Pt and Au atoms, a double-ζ for the 6s and 5d orbitals and single-ζ for the 6p ones, and for the iron atoms, single-ζ quality for the 3s, 3p, and 4p orbitals and double-ζ quality for the 3d and 4s ones. There are two parameters that control the accuracy of the numerical calculations: (i) because the wave function vanishes at the chosen confinement radius rc, whose value is different for each atomic orbital, the energy radii of different orbitals is determined by a single parameter, the energy shif t, which is the energy increase of the atomic eigenstate due to the confinement and (ii) the integrals of the self-consistent terms are obtained with the help of a regular real space grid in which the electron density is projected. The grid spacing is determined by the maximum kinetic energy of the plane waves that can be represented in that grid. We have employed in the calculations an energy shif t of 50 meV and maximum kinetic energy value of 150 Ry; with such values we have a convergence in the results. To avoid spurious electrostatic terms for the use of periodic boundary conditions with charged molecules, a background compensating charge was added, to make the system neutral. DOSY Experiments. DOSY experiments described in this work were carried out on a Bruker Avance spectrometer, 500 MHz, equipped with a 5 mm broadband inverse (BBI) z-axis gradient probe capable of generating 55 G/cm field strengths. Temperature was maintained at 298 K and calibrated with a 4% methanol in methanol-d4 sample. Thermal convection was minimized through constant rotation of the sample at 20 Hz in all experiments without any other modification. DOSY experiments were obtained with a longitudinal echo delay (LED) bipolar gradient pulse pair and 2 spoil gradients pulse sequence (ledbpgp2s in the standard Bruker pulse sequence library). The

gradient shape was sinusoidal and its length (δ) was 0.5 ms, its strength was increased linearly, acquiring 32 gradient levels. A gradient recovery delay of 0.5 ms and an eddy current delay of 5 ms were used. The diffusion time Δ was set at 150 ms. Low and high gradient strengths were set at 2 and 95% of maximum, respectively. The strength of the gradient was first calibrated by measuring the self-diffusion coefficient of the residual HDO signal in a 100% D2O sample at 298 K 16 transients were acquired for. Experiments were processed with the standard Bruker DOSY and T1/T2 software packages (both of them included in Bruker TopSpin version 2.0). Synthesis of Compounds. Compounds [(AuC6F4py)2(μ2-dppm)] (1),40 [(AuC6F4py)2(μ2-dppe)] (2),40 [(AuC6F4py)2(μ2-dppet)] (3),40 [(AuC6F4py)2(μ2-dppp)] (4),40 [(AuC6F4py)2(μ2-dppb)] (5),40 [(AuC6F4py)2(μ2-dppdph)] (6),40 [Pd(dppp)(H2O)2](OTf)2 (a),68 [Pt(dppp) (H2O)2](OTf)2 (b),68 and [Pd(dppf)(H2O)2](OTf)2 (c),68 and [Pt(dppf)(H2O)2](OTf)2 (d)68 were prepared as described previously. Synthesis of (a1)2. A dichloromethane solution (5 mL) of [(AuC6F4py)2(μ2-dppm)] (1) (15 mg, 0.012 mmol) was added dropwise to a dichloromethane solution (5 mL) of [Pd(dppp)(H2O)2](OTf)2 (a) (10 mg, 0.012 mmol) at room temperature. After 2 h of stirring, the reaction mixture was concentrated to 3 mL under vacuum and precipitated with hexane (15 mL). A white solid was obtained in 90% yield (22 mg). Anal. Calcd for C152H112Au4F28N4O12P8Pd2S4: C, 44.58; H, 2.76; N, 1.37; S, 3.13. Found: C, 44.71; H, 2.66; N, 1.33; S, 3.17. 1 H NMR (298 K, CDCl3): 9.04 (br, 8H, Hα‑py), 7.76−7.35 (m, 80H, Ph), 7.11 (d, J(H−H) = 4.8 Hz, 8H, Hβ‑py), 3.82 (t, J(H−P) = 11.1 Hz, 4H, P− CH2-P), 3.29 (m, 8H, P-CH2CH2CH2-P), 2.32 (m, 4H, P-CH2CH2CH2− P). 31P{1H} NMR (298 K, CDCl3): 32.9 (br, P-Au), 6.2 (s, P-Pd). 19F NMR (298 K, CDCl3): −115.0 (m, 8F, Fo), −145.6 (m, 8F, Fm). ESI(+) m/z: 2922.4 ([(a1)3-2OTf]2+, calcd 2922.2), 2581.3 ([(a1)4-3OTf]3+, calcd 2581.1), 1897.2 ([(a1)2-2OTf]2+, [(a1)-OTf]+, calcd 1897.1), 1215.8 ([(a1)2-3OTf]3+, calcd 1215.8), 874.1 ([(a1)-2OTf]2+, calcd 874.1). IR (KBr, cm−1): 1436, 1096 (dppm, dppp), 1253, 1155, 1029 (OTf). Synthesis of (b1)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2dppm)] (1) (15 mg, 0.012 mmol); [Pt(dppp)(H2O)2](OTf)2 (b) (11 mg, 0.012 mmol) A white solid was obtained in 84% yield (22 mg). Anal. Calcd for C152H112Au4F28N4O12P8Pt2S4: C, 42.73; H, 2.64; N, 1.31; S, 3.00. Found: C, 42.31; H, 2.68; N, 1.30; S, 3.02. 1H NMR (298 K, CDCl3): 9.06 (br, 8H, Hα‑py), 7.80−7.34 (m, 80H, Ph), 7.14 (d, J(H−H) = 5.1 Hz, 8H, Hβ‑py), 3.86 (t, J(H−P) = 10.8 Hz, 4H, P−CH 2-P), 3.39 (br, 8H, P-CH 2CH2 CH 2-P), 2.34 (br, 4H, P-CH2CH2CH2-P). 31P{1H} NMR (298 K, CDCl3): 34.2 (br, P-Au), −14.4 (s, 1J(P−Pt) = 3042 Hz, P-Pt). 19F NMR (298 K, CDCl3): −115.1 (m, 8F, Fo), −144.9 (m, 8F, Fm). ESI(+) m/z: 3055.3 ([(b1)64OTf]4+, [(b1)3-2OTf]2+, calcd 3055.2), 2698.9 ([(b1)4-3OTf]3+, calcd 2698.9), 1987.2 ([(b1)2-2OTf]2+, calcd 1987.2), 1274.8 ([(b1)23OTf]3+, calcd 1274.8), 919.1 ([(b1)2-4OTf]4+, [(b1)-2OTf]2+, calcd 919.1). IR (KBr, cm−1): 1439, 1100 (dppm, dppp), 1256, 1153, 1031 (OTf). Synthesis of (c1)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2dppm)] (1) (15 mg, 0.012 mmol); [Pd(dppf)(H2O)2](OTf)2 (c) (12 mg, 0.012 mmol). A violet solid was obtained in 89% yield (24 mg). 1 H NMR (298 K, CDCl3): 9.00 (d, J(H−H) = 5.7 Hz, 8H, Hα‑py), 7.91−7.32 (m, 80H, Ph), 7.06 (d, J(H−H) = 5.4 Hz, 8H, Hβ‑py), 4.91 (s, 8H, Hα‑ferr), 4.71 (s, 8H, Hβ‑ferr), 3.79 (t, J(H−P) = 10.8 Hz, 4H, PCH2-P). 31P{1H} NMR (298 K, CDCl3): 34.0 (s, P-Pd), 33.8 (br, P-Au). 19F NMR (298 K, CDCl3): −115.3 (m, 8F, Fo), −145.0 (m, 8F, Fm). ESI(+) m/z: 3135.4 ([(c1)3-2OTf]2+, calcd 3135.1), 2770.3 ([(c1)4-3OTf]3+, calcd 2770.1), 2039.2 ([(c1)2-2OTf]2+, [(c1)-OTf]+, calcd 2039.1), 945.1 ([(c1)-2OTf]2+, calcd 945.1). IR (KBr, cm−1): 1436, 1100 (dppm, dppf), 1255, 1156, 1029 (OTf). Synthesis of (d1)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2dppm)] (1) (15 mg, 0.012 mmol; [Pt(dppf)(H2O)2](OTf)2 (d) (13 mg, 0.012 mmol). An orange solid was obtained in 88% yield (24 mg). 1 H NMR (298 K, CDCl3): 9.04 (d, J(H−H) = 5.7 Hz, 8H, Hα‑py), 7.87−7.33 (m, 80H, Ph), 7.10 (d, J(H−H) = 5.7 Hz, 8H, Hβ‑py), 4.87 1541


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Article

Synthesis of (d2)2/(d2)>2. Details of the synthesis of (a1)2 were also applied to the synthesis of these compounds. [(AuC6F4py)2(μ2-dppe)] (2) (18 mg, 0.015 mmol); [Pt(dppf)(H2O)2](OTf)2 (d) (17 mg, 0.015 mmol). A yellow solid was obtained in 92% yield (32 mg). (d2)2. 1H NMR (298 K, CDCl3): 8.94 (d superimposed with (d2)>2 signals, J(H−H) = 6.0, Hα‑py), 7.90−7.34 (m, overlapped with (d2)>2 signals, Ph), 7.11 (d superimposed with (d2)>2 signals, J(H−H) = 6.0, Hβ‑py), 4.80 (s, Hα‑ferr), 4.61 (s, Hβ‑ferr), 2.76 (m overlapped with (d2)>2 signals, P-CH2-CH2-P). 19F NMR (298 K, CDCl3): −115.7 (m, Fo), −144.7 (m, Fm) (d2)>2. 1H NMR (298 K, CDCl3): 8.94 (d, Hα‑py), 7.90−7.34 (m, Ph), 7.11 (d, Hβ‑py), 4.72 (s, Hα‑ferr), 4.52 (s, Hβ‑ferr), 2.76 (m, P-CH2CH2-P). 19F NMR (298 K, CDCl3): −116.1 (m, Fo), −144.1 (m, Fm). (d2)2/(d2)>2. 31P{1H} NMR (298 K, CDCl3): 33.5 (s, br, P-Au), 3.0 (s, 1J(P−Pt) = 3403 Hz, P-Pt). ESI(+) m/z: 3289.0 ([(d2)3-2OTf]2+, calcd 3288.9), 2907.0 ([(d2)4-3OTf]3+, calcd 2907.2), 2143.1 ([(d2)22OTf]2+, calcd 2143.1), 1619.1 ([(d2)2-2OTf]2+, calcd 1619.2), 1520.6 ([(d22)-2OTf]2+, calcd 1520.6), 1378.8 ([(d2)2-3OTf]3+, calcd 1378.8), 997.1 ([(d2)-2OTf]2+, calcd 997.1), 898.1 ([d-OTf]+, calcd 898.0). IR (KBr, cm−1): 1444, 1424, 1100, (dppe, dppf), 1256, 1154, 1030 (OTf). Synthesis of (a3)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2dppet)] (3) (15 mg, 0.012 mmol); [Pd(dppp)(H2O)2](OTf)2 (a) (10 mg, 0.012 mmol). A white solid was obtained in 70% yield (17 mg). 1 H NMR (298K, CDCl3): 9.08 (br, 8H, Hα‑py), 7.65−7.37 (m, 84H, P-CHCH-P + Ph), 7.21 (d, J(H−H) = 5.1 Hz, 8H, Hβ‑py), 3.24 (m, 8H, P-CH2CH2CH2-P), 2.28 (m, 4H, P-CH2CH2CH2-P). 31P{1H} NMR (298 K, CDCl3): 39.9 (br, P-Au), 6.9 (s, P-Pd). 19F NMR (298 K, CDCl3): −116.5 (m, 8F, Fo), −144.2 (m, 8F, Fm). ESI(+) m/z: 2597.3 ([(a3)4-3OTf]3+, calcd 2597.1), 1910.2 ([(a3)2-2OTf]2+, [(a3)OTf]+, calcd 1910.1). IR (KBr, cm−1): 1436, 1100 (dppet, dppp), 1250, 1150, 1021 (OTf). Synthesis of (b3)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2-dppet)] (3) (15 mg, 0.012 mmol); [Pt(dppp)(H2O)2](OTf)2 (b) (11 mg, 0.012 mmol). A white solid was obtained in 80% yield (21 mg). 1H NMR (298 K, CDCl3): 9.12 (d, J(H−H) = 4.5 Hz, 8H, Hα‑py), 7.70−7.37 (m, 84H, P-CHCH-P + Ph), 7.21 (d, J(H−H) = 5.7 Hz, 8H, Hβ‑py), 3.34 (m, 8H, P-CH2CH2CH2-P), 2.29 (m, 4H, P-CH2CH2CH2−P). 31P{1H} NMR (298 K, CDCl3): 39.8 (br, P-Au), −14.6 (s, 1J(P−Pt) = 3036 Hz, P-Pt). 19F NMR (298 K, CDCl3): −115.7 (m, 8F, Fo), −143.6 (m, 8F, Fm). ESI(+) m/z: 4147.8 ([(b3)2-OTf]+, calcd 4146.3), 3073.5 ([(b3)32OTf]2+, calcd 3073.2), 2715.4 ([(b3)4-3OTf]3+, calcd 2715.2), 1999.3 ([(b3)2-2OTf]2+, [(b3)-OTf]+, calcd 1999.2), 1282.8 ([(b3)2-3OTf]3+, calcd 1282.8). IR (KBr, cm−1): 1439, 1100 (dppet, dppp), 1256, 1150, 1031 (OTf). Synthesis of (c3)2/(c3)>2. Details of the synthesis of (a1)2 were also applied to the preparation of these compounds. [(AuC6F4py)2 (μ2-dppet)] (3) (15 mg, 0.012 mmol); [Pd(dppf)(H2O)2](OTf)2 (c) (12 mg, 0.012 mmol). A violet solid was obtained in 78% yield (21 mg). 1H NMR (298 K, CDCl3): 8.96 (br, Hα‑py), 7.90−7.49 (m, PCHCH-P + Ph), 7.12 (br, Hβ‑py), 4.88 (br, Hα‑ferr), 4.61 (br, Hβ‑ferr). 31 1 P{ H} NMR (298 K, CDCl3): 39.9 (br, P-Au), 33.7 (s, P-Pd). 19F NMR (298 K, CDCl3): −115.7 to −116.2 (m, Fo), −143.3 to −144.7 (m, Fm). ESI(+) m/z: 2786.3 ([(c3)4-3OTf]3+, calcd 2786.1), 2051.2 ([(c3)2-2OTf]2+, [(c3)-OTf]+, calcd 2051.1). IR (KBr, cm−1): 1436, 1100 (dppet, dppf), 1256, 1147, 1031 (OTf). Synthesis of (d3)2/(d3)>2. Details of the synthesis of (a1)2 were also applied to the preparation of these compounds. [(AuC6F4py)2(μ2dppet)] (3) (15 mg, 0.012 mmol); [Pt(dppf)(H2O)2](OTf)2 (d) (13 mg, 0.012 mmol). A yellow solid was obtained in 80% yield (22 mg). 1 H NMR (298 K, CDCl3): 8.99 (br, Hα‑py), 7.88−7.50 (m, P-CH CH-P + Ph), 7.16 (br, Hβ‑py), 4.84 (br, Hα‑ferr), 4.58 (br, Hβ‑ferr). 31 1 P{ H} NMR (298 K, CDCl3): 39.6 (br, P-Au), 4.8 (s, 1J(P−Pt) = 3400 Hz, P-Pt). 19F- NMR (298 K, CDCl3): −115.6 to −115.9 (m, Fo), −143.1 to −143.6 (m, Fm). ESI(+) m/z: 3286.5 ([(d3)3-2OTf]3+, calcd 3286.2), 2904.7 ([(d3)4-3OTf]3+, calcd 2904.5), 2141.3 ([(d3)22OTf]2+, [(d3)-OTf]+, calcd 2141.1), 1377.8 ([(d3)2-3OTf]2+, calcd

(s, 8H, Hα‑ferr), 4.68 (s, 8H, Hβ‑ferr), 3.83 (t, J(H−P) = 10.8 Hz, 4H, P−CH2-P). 31P{1H} NMR (298 K, CDCl3): 33.8 (s, P-Au), 5.1 (s, P-Pt). 19F NMR (298 K, CDCl3): −115.2 (m, 8F, Fo), −144.9 (m, 8F, Fm). ESI(+) m/z: 2888.5 ([(d1)4-3OTf]3+, calcd 2888.5), 2129.2 ([(d1)2-2(OTf)]2+, [d1-(OTf)]+, calcd 2129.1), 1369.5 ([(d1)23(OTf)]3+, calcd 1369.4), 990.1 ([(d1)2-4(OTf)]4+, [(d1)-2(OTf)]2+, calcd 990.1). IR (KBr, cm−1): 1436, 1097 (dppm, dppf), 1256, 1160, 1027 (OTf). Synthesis of (a2)2/(a2)>2. Details of the synthesis of (a1)2 were also applied to the preparation of these compounds. [(AuC6F4py)2 (μ2-dppe)] (2) (18 mg, 0.015 mmol); [Pd(dppp)(H2O)2](OTf)2 (a) (13 mg, 0.015 mmol). A white solid was obtained in 90% yield (28 mg). (a2)2. Anal. Calcd for (C154H116Au4F28N4O12P8Pd2S4)n: C, 44.86; H, 2.84; N, 1.36; S, 3.11. Found: C, 44.25; H, 2.88; N, 1.32; S, 3.14. 1H NMR (298 K, CDCl3): 9.00 (d, J(H−H) = 5.0 Hz, Hα‑py), 7.88−7.38 (m superimposed with (a2)>2 signals, Ph), 7.16 (d superimposed with (a2)>2 signals, J(H−H) = 5.0 Hz, Hβ‑py), 3.27 (br overlapped with (a2)>2 signals, P-CH2CH2CH2-P), 2.81 (m overlapped with (a2)>2 signals, P-CH2CH2-P), 2.30 (br superimposed with (a2)>2 signals, P-CH2CH2CH2-P). 19F MR (298 K, CDCl3): −115.6 (m, Fo), −145.0 (m, Fm). (a2)>2. 1H NMR (298 K, CDCl3): 9.05 (br, Hα‑py), 7.88−7.38 (m, Ph), 7.16 (d, Hβ‑py), 3.22 (br, P-CH2CH2CH2-P), 2.81 (m, P-CH2CH2-P), 2.30 (br, P-CH2CH2CH2-P). 19F MR (298 K, CDCl3): −116.3 (m, Fo), −144.2 (m, Fm). (a2)2/(a2)>2. 31P{1H} NMR (298 K, CDCl3): 35.0 (s, P-Au), 6.1 (s, P-Pd). ESI(+) (m/z): 2942.8 ([(a2)6-4OTf]4+, [(a2)3-2OTf]2+, calcd 2942.7), 2799.5 ([(a2)4-3OTf]3+, calcd 2799.5), 1912.0 ([(a2)22OTf]2+, [(a2)-OTf]+, calcd 1912.1), 881.1 ([(a2)-2OTf]2+, calcd 881.1), 667.0 ([a-OTf]+, calcd 667.0). IR (KBr, cm−1): 1449, 1422, 1103, (dppe, dppp), 1254, 1155, 1030 (OTf). Synthesis of (b2)2/(b2)>2. Details of the synthesis of (a1)2 were also applied to the preparation of these compounds. [(AuC6F4py)2(μ2dppe)] (2) (18 mg, 0.015 mmol); [Pt(dppp)(H2O)2](OTf)2 (b) (14 mg, 0.015 mmol). A white solid was obtained in 95% yield (31 mg). (b2)2. 1H NMR (298 K, CDCl3): 9.04 (d, J(H−H) = 6.5 Hz, Hα‑py), 7.90−7.31 (m overlapped with (b2)>2 signals, Ph), 7.20 (m, superimposed with (b2)>2 signals, Hβ‑py), 3.37 (br overlapped with (b2)>2 signals, P-CH2CH2CH2-P), 2.77 (m overlapped with (b2)>2 signals, P-CH2CH2-P), 2.45−2.12 (m br overlapped with (b2)>2 signals, P-CH2CH2CH2-P). 19F MR (298 K, CDCl3): −115.5 (m, Fo), −145.0 (m, 8Fm). (b2)>2. 1H NMR (298 K, CDCl3): 9.12 (s, br, Hα‑py), 7.90− 7.31 (m, Ph), 7.20 (m, Hβ‑py), 3.37 (br, P-CH2CH2CH2-P), 2.77 (m, P-CH2CH2-P), 2.45−2.12 (m, br, P-CH2CH2CH2-P). 19F NMR (298 K, CDCl3): −116.1 (m, Fo), −144.2 (m, Fm). (b2)2/(b2)>2. 31P{1H} NMR (298 K, CDCl3): 35.4 (s, P-Au), −15.5 (s, 1J(Pt−P) = 3068 Hz, P-Pt). ESI(+) m/z: 3076.2 ([(b2)3-2OTf]2+, calcd 3076.3), 2717.8 ([(b2)4-3OTf]3+, calcd 2717.9), 2001.2 ([(b2)22OTf]2+, calcd 2001.2), 1284.1 ([(b2)2-3OTf]3+, calcd 1284.1), 1548.2 ([(b2)2)-2OTf]2+, calcd 1548.2), 926.1, ([(b2)-2OTf]2+, calcd 926.1), 756.1 ([b-OTf]+, calcd 756.1). IR (KBr, cm−1): 1449, 1424, 1104, (dppe, dppp), 1256, 1155, 1030 (OTf). Synthesis of (c2)2/(c2)>2. Details of the synthesis of (a1)2 were also applied to the preparation of these compounds. [(AuC6F4py)2(μ2dppe)] (2) (18 mg, 0.015 mmol); [Pd(dppf)(H2O)2](OTf)2 (c) (15 mg, 0.015 mmol). A violet solid was obtained in 93% yield (31 mg). (c2)2. 1H NMR (298 K, CDCl3): 8.95 (br superimposed with (c2)>2 signals, Hα‑py), 7.90−7.34 (m overlapped with (c2)>2 signals, Ph), 7.12 (d superimposed with (c2)>2 signals, J(H−H) = 5.6 Hz, Hβ‑py), 4.89 (s, Hα‑ferr), 4.70 (s, Hβ‑ferr), 2.83 (d overlapped with (c2)2 signals, J(H−P) = 11 Hz, 8H, P-CH2CH2-P). 19F NMR (298 K, CDCl3): −115.7 (m, Fo), −144.4 (m, Fm). (c2)>2. 1H NMR (298 K, CDCl3): 8.95 (br, Hα‑py), 7.90−7.34 (m, Ph), 7.12 (d, Hβ‑py), 4.84 (s, Hα‑ferr), 4.64 (s, Hβ‑ferr), 2.79 (s, P-CH2CH2-P). 19F NMR (298 K, CDCl3): −115.9 (m, Fo), −144.2 (m, Fm). (c2)2/(c2)>2. 31P{1H} NMR (298 K, CDCl3): 34.0 (s, br, P-Au), 32.0 (s, P-Pd). ESI(+) m/z: 3155.9 ([(c2)3-2OTf]2+, calcd 3156.1), 2788.9 ([(c2)4-3OTf]3+, calcd 2789.1), 2053.0 ([(c2)2-2OTf]2+, [(c2)-OTf]+, calcd 2053.0), 1505.0 ([Pd2(dppf)2(OH)2OTf]+, calcd 1505.0), 952.1 ([(c2)-2OTf]2+, calcd 952.1), 809.0 ([c-OTf]+, calcd 809.0). IR (KBr, cm−1): 1442, 1424, 1101, (dppe, dppf), 1258, 1155, 1030 (OTf). 1542


Organometallics

Article

F NMR (298 K, CDCl3): −115.6 (m, 8F, Fo), −144.7 (m, 8F, Fm). ESI(+) m/z: 2925.9 ([(d4)4-3OTf]3+, calcd 2925.9), 2157.2 ([(d4)22OTf]2+, [(d4)-OTf]+, calcd 2157.2), 1681.1 ([Pt2(dppf)2(OH)2OTf]+, calcd 1681.1), 1388.5 ([(d4)2-3OTf]3+, calcd 1388.5), 1004.1 ([(d4)24OTf]4+, [(d4)-2OTf]2+, calcd 1004.1), 806.1 ([Pt(dppf)(C3H5O)]+, calcd 806.1). IR (KBr, cm−1): 1443, 1424, 1101, (dppp, dppf), 1259, 1153, 1030 (OTf). Synthesis of (a5)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2-dppb)] (5) (15 mg, 0.012 mmol); [Pd(dppp)(H2O)2](OTf)2 (a) (10 mg, 0.012 mmol). A white solid was obtained in 80% yield (20 mg). 1H NMR (298 K, CDCl3): 9.03 (d, J(H−H) = 4.8 Hz, 8H, Hα‑py), 7.73− 7.44 (m, 80H, Ph), 6.99 (d, J(H−H) = 5.1 Hz, 8H, Hβ‑py), 3.30 (br, 8H, P-CH2CH2CH2-P), 2.51 (m, 8H, P-CH2(CH2)2CH2-P), 2.33 (m, 4H, P-CH2CH2CH2-P), 2.01 (m, 8H, P-CH2(CH2)2CH2-P). 31P{1H} NMR (298 K, CDCl3): 37.2 (t, 4J(P-F) = 7.0 Hz, P-Au), 7.4 (s, P-Pd). 19 F NMR (298 K, CDCl3): −114.9 (m, 8F, Fo), −145.1 (m, 8F, Fm). ESI(+) m/z: 2985.3 ([(a5)6-4OTf]4+, [(a5)3-2OTf]2+, calcd 2985.2), 2637.2 ([(a5)4-3OTf]3+, calcd 2637.2), 1940.2 ([(a5)2-2OTf]2+, calcd 1940.2), 1243.8 ([(a5)2-3OTf]3+, calcd 1243.8), 895.6 ([(a5)2-4OTf]4+, [(a5)-2OTf]2+, calcd 895.6), 667.0 ([a-OTf]+, calcd 667.0). IR (KBr, cm−1): 1436, 1100 (dppb, dppp), 1250, 1153, 1024 (OTf). Synthesis of (b5)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2-dppb)] (5) (15 mg, 0.012 mmol); [Pt(dppp)(H2O)2](OTf)2 (b) (10 mg, 0.012 mmol). A white solid was obtained in 92% yield (24 mg). 1H NMR (298 K, CDCl3): 9.05 (d, J(H−H) = 4.8 Hz, 8H, Hα‑py), 7.73− 7.44 (m, 80H, Ph), 7.04 (d, J(H−H) = 5.4 Hz, 8H, Hβ‑py), 3.40 (br, 8H, P-CH2CH2CH2-P), 2.52 (m, 8H, P-CH2(CH2)2CH2-P), 2.33 (m, 4H, P-CH2CH2CH2-P), 2.03 (br, 8H, P-CH2(CH2)2CH2-P). 31P{1H} NMR (298 K, CDCl3): 37.1 (t, 4J(P-F) = 7.0 Hz, P-Au), −14.2 (s, 1 J(P-Pt) = 3038 Hz, P-Pt). 19F NMR (298 K, CDCl3): −114.7 (m, 8F, Fo), −145.5 (m, 8F, Fm). ESI(+) m/z: 3118.3 ([(b5)6-4OTf]4+, ([(b5)32OTf]2+, calcd 3118.3), 2755.3 ([(b5)4-3OTf]3+, calcd 2755.3), 2029.2 ([(b5)2-2OTf]2+, calcd 2029.2), 1302.8 ([(b5)2-3OTf]3+, calcd 1302.8), 939.9 ([(b5)2-4OTf]4+, calcd 939.9). IR (KBr, cm−1): 1436, 1104 (dppb, dppp), 1253, 1153, 1027 (OTf). Synthesis of (c5)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2-dppb)] (5) (15 mg, 0.012 mmol); [Pd(dppf)(H2O)2](OTf)2 (c) (12 mg, 0.012 mmol). A violet solid was obtained in 81% yield (21 mg). Anal. Calcd for C172H128Au4F28Fe2N4O12P8Pd2S4: C, 46.29; H, 2.89; N, 1.25; S, 2.87. Found: C, 46.01; H, 2.84; N, 1.29; S, 2.82. 1H NMR (298 K, CDCl3): 8.98 (d, J(H−H) = 3.0 Hz, 8H, Hα‑py), 7.90−7.50 (m, 80H, Ph), 6.91 (d, J(H−H) = 4.8 Hz, 8H, Hβ‑py), 4.92 (s, 8H, Hα‑ferr), 4.70 (s, 8H, Hβ‑ferr), 2.53 (m, 8H, P-CH2(CH2)2CH2-P), 2.00 (m, 8H, P-CH2(CH2)2CH2-P). 31P{1H} NMR (298 K, CDCl3): 36.9 (t, 4J(P− F) = 7.0 Hz, P-Au), 34.2 (s, P-Pd). 19F NMR (298 K, CDCl3): −115.1 (m, 8F, Fo), −144.9 (m, 8F, Fm). ESI(+) m/z: 3198.7 ([(c5)64OTf]4+, [(c5)3-2OTf]2+, calcd 3198.7), 2825.8 ([(c5)4-3OTf]3+, calcd 2825.8), 2082.1 ([(c5)2-2OTf]2+, [(c5)-OTf]+, calcd 2082.1), 1338.8 ([(c5)2-3OTf]3+, calcd 1338.8), 966.6 ([(c5)2-4OTf]4+, [(c5)2OTf]2+, calcd 966.6). IR (KBr, cm−1): 1439, 1097 (dppb, dppf), 1250, 1153, 1024 (OTf). Synthesis of (d5)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2-dppb)] (5) (15 mg, 0.012 mmol); [Pt(dppf)(H2O)2](OTf)2 (d) (13 mg, 0.012 mmol). A yellow solid was obtained in 90% yield (25 mg). Anal. Calcd for C172H128Au4F28Fe2N4O12P8Pt2S4: C, 44.52; H, 2.78; N, 1.21; S, 2.76. Found: C, 44.91; H, 2.81; N, 1.25; S, 2.79. 1H NMR (298 K, CDCl3): 9.01 (d, J(H−H) = 4.8 Hz, 8H, Hα‑py), 7.88−7.51 (m, 80H, Ph), 6.96 (br, 8H, Hβ‑py), 4.87 (s, 8H, Hα‑ferr), 4.66 (s, 8H, Hβ‑ferr), 2.51 (m, 8H, P-CH2(CH2)2CH2-P), 2.03 (m, 8H, P-CH2(CH2)2CH2-P). 31 1 P{ H} NMR (298 K, CDCl3): 36.9 (br, P-Au), 5.4 (s, 1J(P-Pt) = 3334 Hz, P-Pt). 19F NMR (298 K, CDCl3): −114.7 (m, 8F, Fo), −144.6 (m, 8F, Fm). ESI(+) m/z: 2944.6 ([(d5)4-3OTf]3+, calcd 2944.6), 2171.2 ([(d5)2-2OTf]2+, calcd 2171.2), 1397.8 ([(d5)23OTf]3+, calcd 1397.8). IR (KBr, cm−1): 1436, 1097 (dppb, dppf), 1250, 1157, 1031 (OTf).

1377.8), 996.1 ([(d3)2-4OTf]3+, [(d3)-2OTf]+, calcd 996.1). IR (KBr, cm−1): 1437, 1100 (dppet, dppf), 1256, 1154, 1030 (OTf). Synthesis of (a4)2/(a4)>2. Details of the synthesis of (a1)2 were also applied to the preparation of these compounds. [(AuC6F4py)2 (μ2-dppp)] (4) (19 mg, 0.015 mmol); [Pd(dppp)(H2O)2](OTf)2 (a) (13 mg, 0.015 mmol). A white solid was obtained in 90% yield (28 mg). (a4)2. 1H NMR (298 K, CDCl3): 9.03 (d overlapped with (a4)>2 signals, J(H−H) = 5.8 Hz, Hα‑py), 7.89−7.39 (m overlapped with (a4)>2 signals, Ph), 7.15 (d superimposed with (a4)>2 signals, J(H−H) = 5.8 Hz, Hβ‑py), 3.28 (br, overlapped with (a4)>2 signals, P-CH2CH2CH2P-Pd), 3.02 (m, overlapped with (a4)>2 signals, P-CH2CH2CH2−P-Au), 2.40 (br, superimposed with (a4)>2 signals, P-CH2-CH2-CH2-P-Pd), 1.98 (br, superimposed with (a4)>2 signals, P-CH2CH2CH2-P-Au). 19F NMR (298 K, CDCl3): −115.4 (m, Fo), −144.9 (m, Fm). (a4)>2. 1H NMR (298 K, CDCl3): 9.05 (br, Hα‑py), 7.89−7.39 (m, Ph), 7.15 (d, Hβ‑py), 3.18 (br, P-CH2CH2CH2P-Pd), 2.95 (br, P-CH2CH2CH2-P-Au), 2.40 (br, P-CH2-CH2-CH2-P-Pd), 1.98 (br, P-CH2CH2CH2-P-Au). 19F NMR (298 K, CDCl3): −115.6 (m, Fo), −144.5 (m, Fm). (a4)2/(a4)>2. 31P{1H} NMR (298 K, CDCl3): 32.8 (s, br, P-Au), 6.5 (s, P-Pd). ESI(+) m/z: 2964.1 (([(a4)6-4OTf]4+, [(a4)3-2OTf]2+, calcd 2964.2), 2618.5 ([(a4)4-3OTf]3+, calcd 2618.5), 1926.1 ([(a4)22OTf]2+, [(a4)-OTf]+, calcd 1926.1), 888.1 ([(a4)-2OTf]2+, calcd 888.1), 667.0 ([a-OTf]+, calcd 667.0). IR (KBr, cm−1): 1448, 1423, 11043, (dppp), 1252, 1154, 1029 (OTf). Synthesis of (b4)2/(b4)>2. Details of the synthesis of (a1)2 were also applied to the preparation of these compounds. [(AuC6F4py)2(μ2dppp)] (4) (19 mg, 0.015 mmol); [Pt(dppp)(H2O)2](OTf)2 (b) (14 mg, 0.015 mmol). A white solid was obtained in 92% yield (30 mg). (b4)2. 1H NMR (298 K, CDCl3): 9.06 (d overlapped with (b4)>2 signals, J(H−H) = 5.8 Hz, Hα‑py), 7.74−7.41 (m, superimposed with (b4)>2 signals, Ph), 7.18 (d superimposed with (b4)>2 signals, J(H−H) = 5.8 Hz, Hβ‑py), 3.35 (br, overlapped with (b4)>2 signals, P-CH2CH2CH2P-Pt), 2.94 (m, overlapped with (b4)>2 signals, P-CH2CH2CH2-P-Au), 2.22 (br superimposed with (b4)>2 signals, P-CH2CH2CH2-P-Pt), 2.01 (br superimposed with (b4)>2 signals, P-CH2CH2CH2P-Au). 19F NMR (298 K, CDCl3): −115.2 (m, Fo), −144.8 (m, Fm). (b4)>2. 1H NMR (298 K, CDCl3): 9.11 (br, Hα‑py), 7.74−7.41 (m, Ph), 7.18 (d, Hβ‑py), 3.45 (br, P-CH2CH2CH2P-Pt), 2.90 (m, P-CH2CH2CH2P-Au), 2.22 (br, P-CH2CH2CH2-P-Pt), 2.01 (br, P-CH2CH2CH2-P-Au). 19F NMR (298 K, CDCl3): −115.4 (m, Fo), −144.4 (m, Fm). (b4)2/(b4)>2. 31P{1H} NMR (298 K, CDCl3): 32.1 (s, P-Au), −15.5 (s, 1J(P−Pt) = 3046 Hz, P-Pt). ESI(+) (m/z): 3097.2 ([(b4)64OTf]4+, [(b4)3-2OTf]2+, calcd 3097.3), 2736.5 ([(b4)4-3OTf]3+, calcd 2736.6), 2015.2 ([(b4)2-2OTf]2+, calcd 2015.2), 1562.2 ([(b42)2OTf]2+, calcd 1562.2), 1293.5 ([(b4)2-3OTf]3+, calcd 1293.5), 933.1 ([(b4)-2OTf]2+, calcd 933.1), 756.1 ([b-OTf]+, calcd 756.1). IR (KBr, cm−1): 1449, 1424, 1104, (dppp), 1257, 1155, 1030 (OTf). Synthesis of (c4)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2-dppp)] (4) (19 mg, 0.015 mmol); [Pd(dppf)(H2O)2](OTf)2 (c) (15 mg, 0.015 mmol). A violet solid was obtained in 93% yield (31 mg). 1H NMR (298 K, CDCl3): 8.86 (br, 8H, Hα‑py), 7.90−7.38 (m, 80H, Ph), 6.96 (br, 8H, Hβ‑py), 4.83 (s, 8H, Hα‑ferr), 4.60 (s, 8H, Hβ‑ferr), 2.81 (m, 8H, P-CH2CH2CH2-P), 1.85 (m, 4H, P-CH2CH2CH2-P). 31P{1H} NMR (298 K, CDCl3): 35.5 z(t, 4J(P-F) = 8.0 Hz, P-Au), 33.3 (s, P-Pd). 19F NMR (298 K, CDCl3): −115.6 (m, 8F, Fo), −144.7 (m, 8F, Fm). ESI(+) m/z: 3177.1 ([(c4)3-2OTf]2+, calcd 3177.1), 2807.7 ([(c4)4-3OTf]3+, calcd 2807.8), 2067.1 ([(c4)2-2OTf]2+, [(c4)-OTf]+, calcd 2067.1), 1504.9 ([Pd2(dppf)2(OH)2OTf]+, calcd 1505.0), 1329.1 ([(c4)2-3OTf]3+, calcd 1329.1), 959.1 ([(c4)-2OTf]2+, calcd 959.1), 809.0 ([c-OTf]+, calcd 809.0). IR (KBr, cm−1): 1442, 1423, 1101, (dppp, dppf), 1259, 1153, 1030 (OTf). Synthesis of (d4)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2-dppp)] (4) (19 mg, 0.015 mmol); [Pt(dppf)(H2O)2](OTf)2 (d) (17 mg, 0.015 mmol). A yellow solid was obtained in 92% yield (32 mg). 1H NMR (298 K, CDCl3): 9.01 (br, 8H, Hα‑py), 7.90−7.21 (m, 80H, Ph), 7.10 (br, 8H, Hβ‑py), 4.89 (s, 8H, Hα‑ferr), 4.68 (s, 8H, Hβ‑ferr), 2.95 (m, 8H, P-CH2CH2CH2-P), 1.80 (m, 4H, P-CH2CH2CH2-P). 31P{1H} NMR (298 K, CDCl3): 35.9 (s. P-Au), 4.3 (s, 1J(P-Pt) = 3300 Hz, P-Pt).

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Synthesis of (a6)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2dppdph)] (6) (15 mg, 0.011 mmol); [Pd(dppp)(H2O)2](OTf)2 (a) (9 mg, 0.011 mmol). A brownish solid was obtained in 80% yield (19 mg). 1H NMR (298 K, CD2Cl2): 8.95 (d, J(H−H) = 5.2 Hz, 8H, Hα‑py), 7.61−7.30 (m, 96H, P-(C6H4)2-P + Ph), 7.05 (d, J(H−H) = 5.6 Hz, 8H, Hβ‑py), 3.14 (br, 8H, P-CH2CH2CH2-P), 2.20 (m, 4H, PCH2CH2CH2-P). 31P{1H} NMR (298 K, CD2Cl2): 42.7 (t, 4J(P−F) = 8.0 Hz, P-Au), 7.3 (s, P-Pd). 19F NMR (298 K, CD2Cl2): −115.8 (m, 8F, Fo), −143.8 (m, 8F, Fm). ESI(+) m/z: 3129.6 ([(a6)6-4OTf]4+, calcd 3129.5), 2765.3 ([(a6)4-3OTf]3+, calcd 2765.2), 2036.2 ([(a6)22OTf]2+, [(a6)-OTf]+, calcd 2036.2), 667.0 ([a-OTf]+, calcd 667.0). IR (KBr, cm−1): 1436, 1100 (dppdph, dppp), 1246, 1150, 1027 (OTf). Synthesis of (b6)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2dppdph)] (6) (15 mg, 0.011 mmol); [Pt(dppp)(H2O)2](OTf)2 (b) (10 mg, 0.011 mmol). A white solid was obtained in 90% yield (22 mg). 1H NMR (298 K, CD2Cl2): 9.04 (d, J(H−H) = 5.1 Hz, 8H, Hα‑py), 7.77−7.36 (m, 96H, P-(C6H4)2-P + Ph), 7.20 (d, J(H−H) = 5.4 Hz, 8H, Hβ‑py), 3.31 (br, 8H, P-CH2CH2CH2-P), 2.24 (m, 4H, PCH2CH2CH2-P). 31P{1H} NMR (298 K, CD2Cl2): 42.1 (t, 4J(P-F) = 8.0 Hz, P-Au), −15.0 (s, 1J(P-Pt) = 3065 Hz, P-Pt). 19F NMR (298 K, CD2Cl2): −115.6 (m, 8F, Fo), −143.7 (m, 8F, Fm). ESI(+) m/z: 2125.2 ([(b6)2-2OTf]2+, calcd 2125.2), 1367.2 ([(b6)2-3OTf]3+, calcd 1367.2), 988.1 ([(b6)2-4OTf]4+, calcd 988.1). IR (KBr, cm−1): 1432, 1100 (dppdph, dppp), 1260, 1153, 1031 (OTf). Synthesis of (c6)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2dppdph)] (6) (15 mg, 0.011 mmol); [Pd(dppf)(H2O)2](OTf)2 (c) (11 mg, 0.011 mmol). A violet solid was obtained in 85% yield (22 mg). 1H NMR (298 K, CD2Cl2): 8.82 (br, 8H, Hα‑py), 7.87−7.50 (m, 96H, P-(C6H4)2-P + Ph), 7.12 (d, J(H−H) = 5.2 Hz, 8H, Hβ‑py), 4.82 (s, 8H, Hα‑ferr), 4.62 (s, 8H, Hβ‑ferr). 31P{1H} NMR (298 K, CD2Cl2): 40.5 (t, 4J(P−F) = 8.0 Hz, P-Au), 31.9 (s, P-Pd). 19F NMR (298 K, CD2Cl2): −115.7 (m, 8F, Fo), −143.7 (m, 8F, Fm). ESI(+) m/z: 2954.6 ([(c6)4-3OTf]3+, calcd 2954.5), 2179.2 ([(c6)4-4OTf]4+, ([(c6)2-2OTf]2+, [(c6)-OTf]+, calcd 2179.1), 1402.5 ([(c6)23OTf]3+, calcd 1402.4), 1014.6 ([(c6)2-4OTf]4+, [(c6)-2OTf]2+, calcd 1014.6), 809.0 ([c-OTf]+, calcd 809.0). IR (KBr, cm−1): 1436, 1097 (dppdph, dppf), 1246, 1153, 1024 (OTf). Synthesis of (d6)2. Details of the synthesis of (a1)2 were also applied to the preparation of this compound. [(AuC6F4py)2(μ2dppdph)] (6) (15 mg, 0.011 mmol); [Pt(dppf)(H2O)2](OTf)2 (d) (12 mg, 0.011 mmol). A yellow solid was obtained in 78% yield (21 mg). 1H NMR (298 K, CD2Cl2): 8.89 (br, 8H, Hα‑py), 7.86−7.47 (m, 96H, P-(C6H4)2-P + Ph), 7.14 (d, J(H−H) = 5.4 Hz, 8H, Hβ‑py), 4.78 (s, 8H, Hα‑ferr), 4.58 (s, 8H, Hβ‑ferr). 31P{1H} NMR (298 K, CD2Cl2): 41.9 (t, 4J(P-F) = 7.0 Hz, P-Au), 4.2 (s, 1J(P-Pt) = 3418 Hz, P-Pt). 19F NMR (298 K, CD2Cl2): −115.6 (m, 8F, Fo), −143.6 (m, 8F, Fm). ESI(+) m/z: 3072.6 ([(d6)4-3OTf]3+, calcd 3072.6), 2267.2 ([(d6)44OTf]4+, ([(d6)2-2OTf]2+, calcd 2267.2), 1461.8 ([(d6)2-3OTf]3+, calcd 1461.8), 1059.1 ([(d6)2-4OTf]4+, calcd 1059.1). IR (KBr, cm−1): 1436, 1100 (dppdph, dppf), 1253, 1153, 1031 (OTf).

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Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS Financial support for this work was provided by the Ministerio de Ciencia e Innovación (Projects CTQ2009-08795 and CTQ2008-06670-C02-01), the Deutsche Forschungsgemeinschaft (SFB 624 “Templates”), Generalitat de Catalunya (2009SGR-1459), and Factoriá de Crystalización (CONSOLIDER-INGENIO 2010). We thank Dr. Gabriel González for the DOSY NMR experiments and the computer resources, technical expertise, and assistance provided by the Barcelona Supercomputer Center.

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ASSOCIATED CONTENT

S Supporting Information *

Ball and stick representations of the X-ray structure of (c5)2 and (d5)2. Measured and calculated isotope patterns for the spectra shown in Figure 6 and 19F NMR spectra of the obtained assemblies. Representations of b+5 assemblies and Cartesian coordinates of DFT optimized structures. This material is available free of charge via the Internet at http://pubs.acs.org.

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REFERENCES

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Corresponding Author

*For M.F.: phone, +34-93-4039131; E-mail, montse.ferrer@ qi.ub.es. For M.E.: phone, +49-228-732849; E-mail, Marianne. [email protected]. 1544


Organometallics

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Self-Assembly of Heterometallic Metallomacrocycles via Ditopic

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