Luminescent Pt-Ag clusters based on neutral benzoquinolate cyclometalated platinum complexes

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DOI:10.1002/ejic.201201528

Luminescent Pt–Ag Clusters Based on Neutral

Benzoquinolate Cyclometalated Platinum Complexes

Antonio Martín,*^[a]Úrsula Belío,^[a]Sara Fuertes,^[a]and

Violeta Sicilia^[b]

Dedicated to Professor Juan Forniés on the occasion of his 65th birthday

Keywords: Donor–acceptor systems / Heterometallic complexes / Cluster compounds / Silver / Platinum / Luminescence /

Metal–metal interactions / Pi interactions / Density functional calculations

Complexes of the type [Pt(C₆F₅)(bzq)L] {bzq = 7,8-benzo-

quinolinate; L = PPh₃(2), 2,6-diphenylpyridine (pyPh₂, 3),

tetrahydrothiophene (tht, 4), MeCN (5)} were prepared by

replacing the acetone ligand in [Pt(C₆F₅)(bzq)(Me₂CO)] (1)

with the corresponding L ligand. The structures of complexes

2–4 were established by X-ray diffraction. Despite their neu-

tral nature, complexes 1–5 react with AgClO₄in a 2:1 molar

ratio to give the corresponding trinuclear complexes

[{Pt(C₆F₅)(bzq)L}₂Ag]ClO₄{L = Me₂CO (6), PPh₃(7), pyPh₂

(8), tht (9), MeCN (10)}, which contain PtǞAg dative bonds.

The structures of complexes 7, 9, and 10 were established

by X-ray diffraction, which confirmed the existence of Pt–Ag

bonds (ca. 2.8 Å) and short η¹bonding Ag–C interactions

with the C_ipsoatom of bzq (ca. 2.4 Å). Moreover, complexes

3, 4, 7, 9, and 10 show intermolecular π···π interactions be-

tween the aromatic rings of the bzq ligands (separations of

ca. 3.5 Å). The reactions of 1–5 with [Ag(PPh₃)(OClO₃)] in a

1:1 molar ratio proceed with interchange of the ligands be-

tween the metals and the formation of [{Pt(bzq)(C₆F₅)-

(PPh₃)}₂Ag]ClO₄(7) and [AgL₂]ClO₄(X-ray). Only in the case

of L = pyPh₂(3) was the dinuclear complex [(C₆F₅)(bzq)-

(PPh₃)PtAg(pyPh₂)]ClO₄(11) identified, and its structure was

determined by X-ray diffraction. Complex 11 contains a

PtǞAg [2.8147(1) Å] bond and a η¹-Ag–C_ipso(bzq) inter-

action [2.293(1) Å]. The electronic absorption and lumines-

cence behaviors of 1–11 were investigated. The lower-lying

absorption bands of the mononuclear complexes are ascribed

to ligand-centered [¹IL, π–π* (bzq)] character mixed with

some metal-to-ligand charge transfer [¹MLCT 5d(Pt)Ǟπ*-

(bzq)]. For the trinuclear complexes, these bands are as-

signed to ¹ILCT/¹MMЈLCT [π–π*(bzq)]/{d/s(Pt,Ag)}Ǟπ*-

(bzq)] transitions and to mixed ¹MLCT/¹LЈLCT [MLCT

5d(Pt)Ǟπ*(bzq)]/[LЈLCT, Ar_fǞbzq] for dinuclear complex 11

on the basis of time-dependent TD (DFT) calculations carried

out on 2, 4, 5, 9, 10, and 11Me in CH₂Cl₂. Only 2 and the

heteronuclear compounds are emissive in the solid state at

room temperature; however, all of the complexes are emis-

sive at 77 K (solids and glasses). In each case, the main phos-

phorescent emission seems to be due to a transition similar

in character to the lowest-energy electronic absorption.

allic complexes involving Pt^II(d⁸)ǞM dative bonds, for

which the acidic M center is Cu^I, Ag^I, Au^I, Cd^II, Hg^II, Tl^I,

Sn^II, and Pb^II, to be prepared.^[5,13–32]

Introduction

Metallophilic interactions between closed- or pseudo-

closed-shell transition metals (d¹⁰, d⁸, d¹⁰s²) is a field of

great interest in inorganic chemistry.^[1–12]In this respect,

square-planar complexes of Pt^IIare particularly well-suited

systems that have allowed a huge variety of heteropolymet-

These metal–metal bonds can be used as a tool in molec-

ular or crystal engineering, as they act as a sort of link

between different subassemblies. Thus, a wide array of

interesting structural types with different nuclearities has

been reported, from simple linear bimetallic compounds to

infinite 1D chains.^{[15–19,22–24,30,32–39]}Among other interest-

ing properties, some complexes containing Pt–Ag bonds

have been shown to exhibit interesting photophysical and

photochemical properties,^{[1–10,18,31,39–53]}which in some

cases have been exclusively attributed to the presence of

metallophilic bonds.

[a] Instituto de Síntesis Química y Catálisis Homogénea (ISQCH),

CSIC – Universidad de Zaragoza, Departamento de Química

Inorgánica, Facultad de Ciencias,

50009 Zaragoza, Spain

Homepage: http://organomet.unizar.es/platinum/personal/

antoniomartin

[b] Instituto de Síntesis Química y Catálisis Homogénea (ISQCH),

CSIC – Universidad de Zaragoza, Departamento de Química

Inorgánica, Escuela de Ingeniería y Arquitectura de Zaragoza,

Campus Río Ebro,

In the course of our current research, we developed syn-

thetic methods for the preparation of complexes containing

Pt–M bonds, mainly on the basis of the use of perhalo-

Edificio Torres Quevedo, 50018 Zaragoza, Spain

Supporting information for this article is available on the

WWW under http://dx.doi.org/10.1002/ejic.201201528.

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phenyl platinate(II) complexes.^{[13,16,17,34,37,38,54–57]}We ex- neutral [Pt(bzq)(C₆F₅)(L)] complexes have a disadvantage

panded this work with the simultaneous use of strong li- with respect to the previously used [Pt(bzq)(C₆X₅)₂]^–com-

∧

gand-field cyclometalated C N ligands, such as 7,8-benzo- plex, as the anionic nature of this latter complex should

quinolinate (bzq).^{[16,17,39,53]}This strong ligand field causes increase the electron density on the Pt center to thus favor

the d_z₂platinum orbital to raise its energy to favor the for- the formation of the PtǞAg dative bond.^[13]Nevertheless,

mation of stronger PtǞM dative bonds.^[58,59]Thus, we there are examples of neutral platinum complexes that have

have reported that the anionic [Pt(bzq)(C₆X₅)₂]^–(X = F, Cl) been used as starting materials in the preparation of

complex is a suitable starting material for the preparation PtǞAg dative bonds with success.^[32,53]Thus, after the

of complexes with unsupported Pt–M bonds.^[16,17,39]De- preparation of the corresponding [Pt(bzq)(C₆F₅)(L)] start-

pending on the reaction conditions, the complexes obtained ing materials, we have achieved the preparation of several

show different structural features: bimetallic Pt–M trimetallic Pt–Ag–Pt and one bimetallic Pt–Ag complexes,

[{Pt(bzq)(C₆X₅)₂}ML]ⁿ⁺[M = Cd, L = cyclen, X = F, n = which were characterized and studied by X-ray crystallogra-

1;^[16]M = Ag, L = PPh₃, X = F or Cl, n = 0;^[17,39]M = Ag, phy and NMR spectroscopy. Finally, their optical proper-

L = tetrahydrothiophene (tht), X = F, n = 0^[17,39]], trimetal- ties were investigated and time-dependent density func-

lic “sandwich” Pt–Ag–Pt [{Pt(bzq)(C₆F₅)₂}₂Ag]^–,^[17]or the tional theory (TD-DFT) calculations were performed to

polymer

metallic

chain

system

···Pt–Ag–Pt–Ag– gain better insight into the nature of the electronic transi-

Pt···[{Pt(bzq)(C₆F₅)₂}Ag]_x.^[39]All the Pt–Ag complexes, in tions.

addition to containing intermetallic bonds, also contain

very unusual η¹bonding interactions between the silver(I)

center and the C_ipsoatom of the bzq ligand and are ad-

ditionally stabilized by short or long-range π···π stacking

Results and Discussion

interactions between the aromatic rings of the bzq ligands.

All of these complexes exhibited interesting photolumi-

nescent properties. For the [{Pt(bzq)(C₆F₅)₂}Ag(L)] com-

plexes (and also for [{Pt(bzq)(C₆F₅)₂}Ag]_xupon dissolution

in donor solvents such as acetone or THF), the formation

of the Pt–Ag bond results in a significant blueshift in the

lowest-lying absorption relative to that of the

Synthesis and Characterization of Cyclometalated

[Pt(C₆F₅)(bzq)L] {L = PPh₃(2), pyPh₂(3), tht (4),

MeCN (5)}

The [Pt(C₆F₅)(bzq)(Me₂CO)] (1) complex is a suitable

[Pt(bzq)(C₆X₅)₂]^–starting material. This fact has been at- precursor for the preparation of [Pt(C₆F₅)(bzq)L] com-

tributed to the stabilization and modification of the nature plexes because the acetone group is easily replaced by other

of the HOMO, which changes the character of the transi- L ligands.^[60]Thus, the addition of equimolar amounts of

tion from intraligand/metal-to-ligand charge transfer PPh₃, pyPh₂, and tht to separate acetone solutions of 1 at

(¹IL/¹MLCT) in [Pt(bzq)(C₆F₅)₂]^–to the admixture ligand- 0 °C under a protective Ar atmosphere allowed the corre-

to-ligand/metal-to-ligand charge transfer (¹LЈLCT/¹MLCT) sponding [Pt(C₆F₅)(bzq)L] {L = PPh₃(2), pyPh₂(3), tht

in the bimetallic fragments. The emission in [{Pt(bzq)- (4)} complexes to be obtained as yellow solids that precipi-

(C₆F₅)₂}Ag(L)] is also mainly associated with an admixture tated after partial evaporation of the solvent. The

3

of MLCT/³LЈLCT, which is only slightly modified by the [Pt(C₆F₅)(bzq)(MeCN)] (5) complex was obtained by dis-

Ag center. By contrast, both the experimental data in the solving 1 in acetonitrile under the same conditions. After

solid state and the theoretical calculations on 2 min of stirring, the solvent was removed to dryness under

“[{Pt(bzq)(C₆F₅)₂}Ag]” as a model for [{Pt(bzq)(C₆F₅)₂}- vacuum, and the resulting yellow solid was identified as 5

Ag]_xsuggest that excitation of the polymer moves the elec- (see the Exp. Sect.).

tron density from the platinum fragments; the C₆F₅rings

The IR spectra of complexes 2–5 confirm the replace-

have a remarkable contribution to an orbital with strong Pt ment of acetone in 1, as the ν_COvibration band at

and Ag metallic character. Absorption and emission of the 1669 cm^–1is absent, and the bands corresponding to the

polymer in the solid state is therefore suggested to be asso- corresponding ligands incorporated into the coordination

ciated with an electronic transition of

a

mixed sphere of the Pt atoms are now present (see the Exp. Sect.).

1

[Pt(bzq)ǞAg]/[Ar_fǞAg] character. For the trimetallic The H NMR spectra of these complexes also show signals

[{Pt(bzq)(C₆F₅)₂}₂Ag]^–complex, two different polymorphs due to the new ligands, besides the ones that can be attrib-

were obtained from acetone/n-hexane, and they exhibited uted to the bzq ligand with the expected relative intensity.

visibly different luminescence at room temperature. The The ¹⁹F NMR spectra of 2–5 present the same pattern of

crystal structures of both anions are different, not only in three signals corresponding to the pentafluorophenyl li-

their form, with a different conformation of the platinum gand. The two ortho-F atoms cause one downfield signal

planes, but also in terms of packing.

with platinum satellites. At higher field, one signal for the

In this paper we continue our study on these kinds of meta-F atom and one for the para-F atom can be observed.

complexes by exploring the ability of the [Pt(bzq)(C₆F₅)(L)] For 2, the ³¹P NMR spectrum shows a singlet with plati-

{L = Me₂CO, PPh₃, 2,6-diphenylpyridine (pyPh₂), tht, num satellites attributable to the phosphorus atom of the

MeCN} starting materials to form new complexes of di- PPh₃ligand. All the NMR details are compiled in the Exp.

verse nuclearity containing Pt–Ag bonds. In principle, the Sect.

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The structures of complexes 2, 4, and 5 were established

by X-ray diffraction studies. Figures 1, 2, and 3 show views

of the corresponding complexes, and Tables 1, 2, and 3 list

a selection of relevant bond lengths and angles. All three

complexes are square-planar complexes, and the bzq ligand

is coplanar to the metal plane. The pentafluorophenyl li-

gand is in a trans position with respect to the nitrogen atom

of the bzq ligand. As was previously observed in other plati-

num(II) complexes containing the bzq ligand, the com-

plexes establish a supramolecular arrangement through

π···π interactions of the bzq aromatic ring system of dif-

ferent moieties, which stack in a parallel, head-to-tail fash-

Figure 3. View of the molecular structure of [Pt(C₆F₅)(bzq)-

(MeCN)] (5).

Table 1. Selected bond lengths and angles for [Pt(C₆F₅)(bzq)(PPh₃)]·

0.2Me₂CO (2·0.2Me₂CO).

Bond length [Å]

Pt(1)–C(1)

Pt(1)–N(1)

2.015(6)

2.107(5)

Pt(1)–C(17)

Pt(1)–P(1)

2.041(6)

2.3224(16)

Bond angle [°]

C(1)–Pt(1)–C(17) 92.5(2)

C(17)–Pt(1)–N(1) 80.6(2)

C(17)–Pt(1)–P(1) 176.16(19)

C(1)–Pt(1)–N(1)

C(1)–Pt(1)–P(1)

N(1)–Pt(1)–P(1)

172.7(2)

89.36(17)

97.70(15)

Figure 1. View of the molecular structure of [Pt(C₆F₅)(bzq)(PPh₃)]

(2).

Table 2. Selected bond lengths and angles for [Pt(C₆F₅)(bzq)(tht)]·

2/3CH₂Cl₂(4·2/3CH₂Cl₂).

Bond length [Å]

Pt(1)–C(17)

Pt(1)–N(1)

2.000(7)

2.078(7)

Pt(1)–C(1)

Pt(1)–S(1)

2.003(8)

2.3719(19)

Bond angle [°]

C(17)–Pt(1)–C(1) 91.8(3)

C(17)–Pt(1)–N(1) 82.1(3)

C(17)–Pt(1)–S(1) 176.1(2)

C(1)–Pt(1)–N(1)

C(1)–Pt(1)–S(1)

173.9(3)

92.1(2)

N(1)–Pt(1)–S(1)

93.98(19)

Table 3. Selected bond lengths and angles for [Pt(C₆F₅)-

(bzq)(MeCN)] (5).

Bond length [Å]

Pt–C(17)

Pt–N(2)

1.993(7)

2.070(7)

Pt–C(1)

Pt–N(1)

2.016(8)

2.085(7)

Bond angle [°]

C(17)–Pt–C(1)

C(1)–Pt–N(2)

C(1)–Pt–N(1)

93.6(3)

90.3(3)

173.9(3)

C(17)–Pt–N(2)

C(17)–Pt–N(1)

N(2)–Pt–N(1)

175.5(3)

81.6(3)

94.6(3)

ion. Thus, in 2 four units of the [Pt(C₆F₅)(bzq)(PPh₃)] com-

plex are stacked (Figure S1, Supporting Information) with

interplanar bzq distances of ca. 3.4 Å, whereas in 4 the

asymmetric unit contains three stacked units of the

[Pt(C₆F₅)(bzq)(tht)] complex (Figure 2, bottom) with in-

terplanar bzq distances of ca. 3.3–3.4 Å. No other π···π in-

teractions are observed among these groups of four or three

Figure 2. Top: view of the molecular structure of [Pt(C₆F₅)(bzq)-

(tht)] (4). Bottom: supramolecular arrangement of the three units

showing the π···π stacking.

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units and other adjacent moieties. In contrast, in 5 an infi- solids; their structures were elucidated through analytical

nite array of stacked [Pt(C₆F₅)(bzq)(MeCN)] units is found and spectroscopic data (see the Exp. Sect.). When the reac-

with similar interplanar bzq distances (Figure S2, Support- tions are carried out under the same experimental condi-

ing Information). This kind of supramolecular arrangement tions but in a 1:1 molar ratio, only oily residues were ob-

has been found in other complexes with the bzq li- tained, which were identified as mixtures of 6–10 and unre-

gand^{[17,18,39,53,60,61]}and in other cyclometalated planar li- acted AgClO₄.

gands.^[32,62]Along with H-bonding, this kind of π···π stack-

These results indicate that only the trinuclear complexes

ing is one of the most important secondary interac- (Scheme 1, c) could be isolated. The stabilities of the trinu-

tions^[63–68]in the field of modern supramolecular chemis- clear complexes relative to those of the complexes that

try,^[69–72]as it plays an important role in processes such as could be obtained by using a 1:1 molar ratio can be ration-

molecular self-assembly and self-recognition of aromatic alized by the neutral character of starting Pt^IIproducts 1–

entities in the crystal state.

5. These complexes would not have enough electron density

on their basic metal Pt^IIcenter to satisfy the requirement

of one acidic silver center, but two Pt^IIcenters have to coop-

erate to stabilize the trinuclear complex with the formation

of two PtǞAg bonds with the same Ag^Icenter. Notably,

as mentioned above, the [(C₆F₅)₂(bzq)PtAg]_xcomplex,^[39]

which is similar to the one that would result from the path

depicted in Scheme 1 (b) does exist. In that case, the start-

ing material is an anionic Pt^IIcomplex (i.e., [Pt(C₆F₅)₂-

(bzq)]^–), and thus, the Pt^IIcenter seems to be more able to

fulfil the electron necessities of the silver center.

Reactivity of 1–5 towards AgClO₄:Synthesis and

Characterization of [{Pt(C₆F₅)(bzq)L}₂Ag]ClO₄

{L = Me₂CO (6), PPh₃(7), pyPh₂(8), tht (9), MeCN (10)}

Complexes 1–5 were treated with AgClO₄with the aim

to prepare heterometallic complexes containing PtǞAg

dative bonds. As mentioned above, it was previously re-

ported that anionic Pt^IIprecursors favor the obtainment of

such PtǞM complexes, because the additional electron

density borne by the platinum center can be donated to the

acidic center.^[13]Hence, despite the fact that some neutral

Pt^IIprecursors have been used,^[32,53]the greatest success in

the preparation of complexes with PtǞM donor–acceptor

bonds was achieved with anionic Pt^IIcomplexes as starting

materials.

The IR spectra of complexes 6–10 show the presence of

two signals assignable to the ClO₄anion: one sharp band

at 621 cm^–1and another broad band at 1095 cm^–1. More-

over, the expected signals caused by bzq and the corre-

sponding L ligand can be found.

1

The H NMR spectra of complexes 6–10 show signals

corresponding to the L ligands, in addition to the ones at-

tributed to the bzq ligand with the expected relative inten-

sity. The ¹⁹F NMR spectra of 6–10 present only one set of

signals, which is indicative of the equivalence of the penta-

fluorophenyl groups of the two “Pt(C₆F₅)(bzq)L” subunits.

The pattern of the signals is similar to the one described

above for complexes 2–5. Finally, for 7 the ³¹P NMR spec-

trum shows a singlet signal with platinum satellites attribut-

able to the phosphorus atom of the PPh₃ligand. Details of

the NMR spectroscopic data are compiled in the Exp. Sect.

In any case, we investigated the reactivities of 1–5

towards AgClO₄in molar ratios of 1:1 and 2:1. The 1:1

molar ratio could lead to the preparation of discrete di-

nuclear [Pt–Ag]⁺complexes (Scheme 1, a) and polymeric

infinite [···Pt–Ag–Pt–Ag–Pt···]ⁿ⁺species (Scheme 1, b),

whereas the 2:1 molar ratio led to trinuclear [Pt–Ag–Pt]⁺

“sandwiches” (Scheme 1, c).

Crystal Structures of [{Pt(C₆F₅)(bzq)L}₂Ag]ClO₄

{L = PPh₃(7), tht (9), MeCN (10)}

The structures of complexes 7, 9, and 10 were established

by X-ray diffraction studies. Figures 4, 5, and 6 show views

of the corresponding complexes, and Tables 4, 5, and 6 list

a selection of relevant bond lengths and angles.

Determination of the crystal structures confirmed that,

in the solid state, these complexes are trinuclear with a

“sandwich” disposition. The two “Pt(C₆F₅)(bzq)L” frag-

ments are linked to the silver center through PtǞAg do-

nor–acceptor bonds. The Pt–Ag distances are 2.823(1) and

Scheme 1.

Thus, the reactions of complexes 1–5 with AgClO₄in a 2.745(1) Å for 7, 2.835(1) and 2.841(1) Å for 9, and 2.792(1)

2:1 molar ratio were carried out in acetone at 0 °C under and 2.765(1) Å for 10. These distances are in the range

an Ar atmosphere in the absence of light for 30 min. After found for other complexes containing PtǞAg

workup

of

the

reaction

mixtures,

compounds bonds.^{[13,17,23,24,32,34,35,39,54,73–79]}The structures of 7, 9, and

[{Pt(C₆F₅)(bzq)L}₂Ag]ClO₄{L = Me₂CO (6), PPh₃(7), 10 can be compared with the ones described for the two

pyPh₂(8), tht (9), MeCN (10)} were obtained as yellow polymorphs of the analogous (NBu₄)[{Pt(C₆F₅)₂(bzq)}₂Ag]

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Figure 6. View of the molecular structure of the cation of

[{Pt(C₆F₅)(bzq)(MeCN)}₂Ag]ClO₄(10).

Table 4. Selected bond lengths and angles for [{Pt(C₆F₅)(bzq)-

(PPh₃)}₂Ag]ClO₄·CH₂Cl₂(7·CH₂Cl₂).

Bond length [Å]

Pt(1)–C(1)

Pt(1)–N(1)

Pt(1)–Ag

Pt(2)–C(36)

Pt(2)–P(2)

Ag–C(17)

2.028(4)

2.106(3)

2.8225(3)

2.071(4)

2.3336(10) Pt(2)–Ag

2.351(4)

Pt(1)–C(17)

Pt(1)–P(1)

Pt(2)–C(20)

Pt(2)–N(2)

2.062(4)

2.3472(10)

2.024(4)

2.122(3)

2.7447(3)

2.460(3)

Figure 4. Top: view of the molecular structure of the cation of

[{Pt(C₆F₅)(bzq)(PPh₃)}₂Ag]ClO₄(7). Bottom: supramolecular ar-

rangement of the infinite π···π stacking array.

Ag–C(36)

Bond angle [°]

C(1)–Pt(1)–C(17)

C(17)–Pt(1)–N(1) 80.36(14)

C(17)–Pt(1)–P(1)

90.64(15)

C(1)–Pt(1)–N(1)

C(1)–Pt(1)–P(1)

168.49(13)

91.30(10)

98.11(9)

176.22(10) N(1)–Pt(1)–P(1)

C(20)–Pt(2)–C(36) 91.66(15)

C(20)–Pt(2)–N(2) 168.58(13)

C(20)–Pt(2)–P(2) 89.74(11)

173.72(10) N(2)–Pt(2)–P(2) 99.14(9)

C(36)–Pt(2)–N(2) 80.29(13)

C(36)–Pt(2)–P(2)

C(17)–Ag–C(36)

134.78(13) Pt(2)–Ag–Pt(1)

161.994(13)

Table 5. Selected bond lengths and angles for [{Pt(C₆F₅)(bzq)-

(tht)}₂Ag]ClO₄·1.5Me₂CO (9·1.5Me₂CO).

Bond length [Å]

Pt(1)–C(1)

Pt(1)–N(1)

Pt(1)–Ag

Pt(2)–C(36)

Pt(2)–S(2)

Ag–C(17)

2.001(5)

2.081(5)

2.8350(5)

2.020(5)

2.3686(14) Pt(2)–Ag

2.347(5)

Pt(1)–C(17)

Pt(1)–S(1)

Pt(2)–C(20)

Pt(2)–N(2)

2.019(5)

2.3685(14)

2.002(5)

2.092(5)

2.8410(5)

2.339(6)

Ag–C(36)

Bond angle [°]

Figure 5. View of the molecular structure of the cation of

C(1)–Pt(1)–C(17) 93.6(2)

C(17)–Pt(1)–N(1) 81.6(2)

C(1)–Pt(1)–N(1)

C(1)–Pt(1)–S(1)

171.74(19)

92.72(14)

92.77(13)

[{Pt(C₆F₅)(bzq)(tht)}₂Ag]ClO₄(9).

C(17)–Pt(1)–S(1)

171.82(16) N(1)–Pt(1)–S(1)

complex,^[17]which is also a “sandwich”-type complex with

a Pt–Ag–Pt bond system that is similar to that found in the

complex described here. As mentioned above, the starting

material for (NBu₄)[{Pt(C₆F₅)₂(bzq)}₂Ag] is anionic, and

the resulting trinuclear complex is also anionic. Thus,

C(20)–Pt(2)–C(36) 93.9(2)

C(36)–Pt(2)–N(2) 81.6(2)

C(20)–Pt(2)–N(2) 173.8(2)

C(20)–Pt(2)–S(2)

91.98(15)

92.69(13)

149.139(19)

C(36)–Pt(2)–S(2)

C(36)–Ag–C(17)

173.95(18) N(2)–Pt(2)–S(2)

154.1(2) Pt(1)–Ag–Pt(2)

stronger Pt–Ag bonds and, hence, shorter Pt–Ag distances distances of 2.758(1), 2.684(1), 2.702(1), and 2.690(1) Å,

could be expected in (NBu₄)[{Pt(C₆F₅)₂(bzq)}₂Ag]. The which, in general, are slightly shorter than the ones found

two polymorphs of this anionic “sandwich” show Pt–Ag in 7, 9, and 10, but this difference can also be attributed to

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Table 6. Selected bond lengths and angles for [{Pt(C₆F₅)(bzq)- 34.1(1)° for Pt(2) in 9, and 32.4(2)° for Pt(1) and 32.6(2)°

(NCMe)}₂Ag]ClO₄·2.5CH₂Cl₂·0.5n-C₆H₁₄

(10·2.5CH₂Cl₂·0.5n-

for Pt(2) in 10. In principle, the best disposition for an opti-

mal PtǞM occurs when the intermetallic line is perpendic-

ular to the Pt square-plane, which maximizes overlap of the

full 5d_z₂Pt^IIorbital containing the electron pair donated to

form the dative bond with the empty orbitals of the acidic

metal center. Nevertheless, in these kinds of complexes

there are some other factors that force the Pt–Ag bond to

deviate from this ideal perpendicular disposition. Some of

these factors are electronic, such as η¹-Ag–C interactions or

o-F contacts, or steric resulting from the presence of bulky

ligands, such as C₆F₅or PPh₃, along with other less steri-

cally demanding ligands, such as bzq, Me₂CO, or MeCN.

In this line, complexes 7, 9, and 10 show substantial con-

formational differences in the relative dispositions of the

two square-planar environments of each structure. In prin-

ciple, two relative dispositions of the Pt planes are possible

in these “sandwich” trinuclear complexes (see Scheme 2). In

disposition A, the coordination of the two Pt centers takes

C₆H₁₄).

Bond length [Å]

Pt(1)–C(17)

Pt(1)–N(3)

Pt(1)–Ag

Pt(2)–C(36)

Pt(2)–N(2)

Ag–C(17)

1.999(7)

2.061(9)

2.7924(8)

2.006(7)

2.096(7)

2.425(8)

Pt(1)–C(1)

Pt(1)–N(1)

Pt(2)–C(20)

Pt(2)–N(4)

Pt(2)–Ag

2.029(8)

2.072(7)

2.013(10)

2.063(7)

2.7646(8)

2.467(8)

Ag–C(36)

Bond angle [°]

C(17)–Pt(1)–C(1) 93.7(3)

C(17)–Pt(1)–N(3) 175.3(3)

C(17)–Pt(1)–N(1) 83.1(3)

N(3)–Pt(1)–N(1)

C(1)–Pt(1)–N(3)

C(1)–Pt(1)–N(1)

90.9(3)

176.8(3)

92.2(3)

C(20)–Pt(2)–C(36) 93.2(3)

C(36)–Pt(2)–N(4) 174.4(3)

C(36)–Pt(2)–N(2) 81.9(2)

C(20)–Pt(2)–N(4) 90.0(3)

C(20)–Pt(2)–N(2) 175.1(3)

N(4)–Pt(2)–N(2)

94.8(3)

147.79(3)

C(17)–Ag–C(36)

136.59(19) Pt(2)–Ag–Pt(1)

steric factors caused by the disposition of the ligands in the place in such a way that the positions of the N and C_ipso

complexes or to intermolecular packing forces.^[80]

atoms of each bzq ligand alternate, and thus, the relative

Besides the Pt–Ag bonds, in complexes 7, 9, and 10 the positions of the L and C₆F₅ligands of each “Pt(C₆F₅)-

silver center also establishes a short η¹interaction with the (bzq)L” fragment also alternate. In contrast, in disposi-

C

_ipsoatom of the bzq ligands [C(17) and C(36) in Figures 4– tion B, the relative positions of all the analogous atoms

6] with Ag–C distances of 2.351(4) and 2.460(3) Å for 7, bonded to the Pt center in each “Pt(C₆F₅)(bzq)L” fragment

2.347(8) and 2.339(8) Å for 9, and 2.425(8) and 2.467(8) Å coincide. These two conformations were previously found

for 10. These η¹-Ag–C contacts were previously found in in similar complexes containing the bzq and C₆F₅li-

other “(bzq)PtǞAg”^[17,39]and “(L)PtǞAg” complexes, in gands.^[17,39]Moreover, it is necessary to take into consider-

which L is another aromatic planar cyclometalated ligand ation the possibility that the “Pt(C₆F₅)(bzq)L” fragments

similar to bzq, such as 2-phenylpyridinate, 2-(2-tienyl)pyrid- turn around the Pt–Ag bonds and the variability of the Pt–

inate,^[23]or ethyl 2,6-diphenylisonicotinate.^[32]These η¹-Ag– Ag–Pt angles (see above). For all these reasons, complexes

C interactions are important and, along the PtǞAg bonds, 7, 9, and 10 {and (NBu₄)[{Pt(C₆F₅)₂(bzq)}₂Ag]^[17]} are very

contribute to fulfil the electron density requirements of the flexible and are able to adapt their geometry to the elec-

acidic silver center. The affinity of this metal for some π- tronic and steric demands mentioned above, as well as the

donor systems is well known,^{[33,69–72,81–89]}and the η¹and crystal-packing effects.

η²coordination modes are most common. The Ag–C lines

are usually perpendicular to the aromatic planar ring sys-

tem, which is also more or less observed in 7, 9, and 10,

given the geometric limitations imposed by the Pt–Ag

bonds. Thus, the angles between the Ag–C lines and the

perpendicular to the best bzq planes are 15.5(1) and

20.3(1)° for 7, 13.6(1) and 12.1(1)° for 9, and 14.6(2) and

18.3(2)° for 10.

In 7, the silver center is located relatively close to one of

the ortho fluorine atoms of each pentafluorophenyl group

[Ag···F(5) 2.838(2) Å, Ag···F(6) 2.691(2) Å], whereas in 10

only one o-F is relatively near the Ag atom [Ag···F(6)

2.699(10) Å], and in 9, the separation is longer [Ag···F(5)

2.914(5) Å, Ag···F(6) 2.898(4) Å]. These short distances are

frequently found in pentafluorophenyl complexes and are

considered as secondary contacts that also contribute to

complete the electron donation to the acidic silver and,

thus, to the final stabilization of the complex.^[13]

The Pt–Ag–Pt angle is 161.99(1)° in 7, 149.14(2)° in 9,

and 147.79(3)° in 10. The Pt–Ag lines are not perpendicular

to the square-planar environments of the Pt atoms; the

angles to the perpendicular to these planes are 32.1(1)° for

Scheme 2.

Thus, in complex 7 the dihedral angle between the best

Pt(1) and 24.7(1)° for Pt(2) in 7, 30.1(1)° for Pt(1) and Pt square-planes is 25.6(1)°, and these planes lean over one

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another in such a way that the bzq ligands of the two sub- Ar atmosphere. After 30 min of stirring, the acetone was

units are almost eclipsed [torsion angle N(1)–Pt(1)–Pt(2)– completely removed, and the oily residues were treated with

N(2) = 67.4(1)°] and adopt conformation A (Scheme 2). n-hexane, to give yellow solids that were filtered off and

This disposition allows maximum separation between the dried in air.

phenyl groups of the two PPh₃ligands, which are the bulki-

The most significant aspect of the spectroscopic data of

est in this complex. Conformation A is also observed in 9, these solids is the presence of a singlet signal with platinum

with a dihedral angle of 24.4(1)° between the two Pt planes, satellites in the ³¹P NMR spectrum, because this indicates

but here, the two “Pt(C₆F₅)(bzq)(tht)” fragments are ro- that all of the solids correspond to complexes containing a

tated and the torsion angle N(1)–Pt(1)–Pt(2)–N(2) is only Pt–PPh₃bond. These spectroscopic data seem to indicate

15.4(1)°. In contrast, complex 10 shows conformation B, that, at least for complexes 1 and 3–5, the PPh₃ligand mi-

probably to allow maximum separation of the most steri- grates from the silver center to the platinum center. In all

cally demanding ligands of the complex, in this case, the cases, crystals suitable for X-ray diffraction analysis were

pentafluorophenyl groups.

obtained and identified as [{Pt(bzq)(C₆F₅)(PPh₃)}₂Ag]ClO₄

Study of the supramolecular packing of complexes 7, 9, (7). In the case in which the starting material was

and 10 has shown an infinite array of cations connected [Pt(C₆F₅)(bzq)(PPh₃)] (2), a second signal was also ob-

through π···π interactions of the planar aromatic rings of served in the ³¹P NMR spectrum of the resulting material.

the bzq ligands, in a similar fashion to that described above At room temperature, this signal is broad and resolves at

for complexes 2, 4, and 5 and in other complexes previously –70 °C into a doublet of doublets, a pattern typical for a

reported.^{[17,18,32,39,53,60–62]}The interplanar separations are phosphorus atom bonded to a silver center (silver has two

close to 3.4 Å, and as an example, Figure 4 (bottom) shows NMR active isotopes, ¹⁰⁷Ag, 51.8% abundance, and ¹⁰⁹Ag,

a fragment of this array as found in complex 7.

48.2% abundance). Crystals obtained from the crude solid

could be also studied by X-ray diffraction, and they were

identified as [Ag(PPh₃)₂](ClO₄).

For the case in which the starting material was

[Pt(C₆F₅)(bzq)(pyPh₂)] (3), it was possible to obtain crystals

Reactivities of 1–5 towards [Ag(PPh₃)(OClO₃)]

As the reactions of complexes 1–5 with AgClO₄did not that were identified through X-ray diffraction as the dinu-

result in dinuclear discrete complexes or polymeric infinite clear [(C₆F₅)(bzq)(PPh₃)PtAg(pyPh₂)]ClO₄(11) complex,

species containing Pt–Ag bonds, we tried another silver rea- which contains a donor–acceptor PtǞAg bond (see be-

gent: [Ag(PPh₃)(OClO₃)]. In this complex, the silver center low).

coordinates to a strong PPh₃ligand, which blocks one of

All these results are summarized in Scheme 3. It seems

its possible coordination positions and contributes to fulfil that migration of the PPh₃ligand from Ag to Pt corre-

the electronic requirements of the acidic silver. The aim was sponds to a higher lability of the Pt–O bonds (when L =

to prepare dinuclear [Pt(bzq)(C₆F₅)LAg(PPh₃)]ClO₄com- Me₂CO), Pt–N bonds (when L = MeCN or pyPh₂), or Pt–

plexes containing a donor–acceptor PtǞAg bond. This S bonds (when L = tht) than the Pt–P bonds. The final

synthetic strategy is well known and has been used with formation of trinuclear sandwich 7 is probably caused by

positive results.^{[13,17,54,79]}

the final stability of this complex. The existence of [AgL₂]⁺

Thus, complexes 1–5 were treated with [Ag(PPh₃)- has only been confirmed for L = PPh₃, but given the pres-

1

(OClO₃)] in 1:1 molar ratio in acetone at 0 °C under an ence of signals in the IR and H NMR spectra for other

Scheme 3.

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diagnostic groups in L, it is sensible to assume an overall tance of 2.8147(1) Å. This distance is similar to those found

reaction process as depicted in Scheme 3 (b). in [{Pt(C₆F₅)(bzq)(PPh₃)}₂Ag]ClO₄(7) [cf. 2.823(1) and

However, the identification of [(C₆F₅)(bzq)(PPh₃)PtAg- 2.745(1) Å], which also contains the “Pt(C₆F₅)(bzq)(PPh₃)”

(pyPh₂)]ClO₄(11) is interesting. Its existence could indicate fragment. In contrast, it is slightly longer that those found

that the formation of trinuclear 7 occurs through the path- in the analogous complexes [(C₆X₅)₂(bzq)PtAg(PPh₃)]^–

way given in Scheme 3 (a). For some reason, intermediate [2.728(1) Å for X = F and 2.675(3) Å for X = Cl],^[17]per-

compound 11 could only be detected in the case of L = haps because of the anionic nature of these latter com-

pyPh₂. Apart from evident electronic reasons, an important pounds in comparison with the neutral nature of 11. More-

difference between the other L ligands used (i.e., Me₂CO, over, as described above for complexes 7, 9, and 10 and

MeCN, tht) and pyPh₂is size and, thus, the resulting steric other similar “(bzq)PtǞAg” complexes,^[17,39]the silver cen-

hindrance caused by the latter. Thus, kinetic effects could ter establishes an η¹-Ag–C interaction with the ipso carbon

be the reason why 11 evolves more slowly than the rest of atom of the bzq ligand with a Ag–C(17) distance of

the complexes, and some crystals could be formed prior to 2.293(1) Å. This value is shorter than the one found in 7

its complete conversion into 7.

[cf. 2.351(4) and 2.460(3) Å], 9 [cf. 2.347(8) and 2.339(8) Å],

and 10 [cf. 2.425(8) and 2.467(8) Å] and in [(C₆X₅)₂(bzq)-

PtAg(PPh₃)]^–[2.352(3) Å for X = F and 2.557(5) Å for X =

Cl],^[17]which seems to indicate a stronger interaction. In

fact, the silver center clearly leans toward the C_ipsoposition

of the bzq ligand; the angle between the Pt–Ag line and the

perpendicular of the best Pt square-plane is 44.6(1)°, which

is a large value {compare with the analogous angles 32.1(1)

and 24.7(1)° in 7, 30.1(1) and 34.1(1)° in 9, 32.4(2) and

32.6(2)° in 10, 34.9(1)° in [(C₆F₅)₂(bzq)PtAg(PPh₃)]^–,^[17]

and 27.2(1)° in [(C₆Cl₅)₂(bzq)PtAg(PPh₃)]^–[17]}, and the Pt–

Ag–N(2) angle is 146.5(1)°. This “so bent” disposition is

probably caused by the steric hindrance resulting from the

two PPh₃and pyPh₂bulky ligands present in 11, which try

to stay as far away from one another as much as possible.

The coordination sphere of the silver center is completed

by the pyPh₂ligand, with a Ag–N(2) distance of 2.190(1) Å,

which is in the usual range for this type of bond.^[90–95]

In this case, complex 11 does not show extended inter-

molecular interactions through π···π interactions of the

planar aromatic rings of the bzq ligand.

Crystal Structure of [(C₆F₅)(bzq)(PPh₃)PtAg(pyPh₂)]ClO₄

(11)

As mentioned above, the crystal structure of complex 11

was determined by X-ray diffraction. Figure 7 shows a view

of the complex cation, and Table 7 lists a selection of rel-

evant bond lengths and angles.

Photophysical Properties

Absorption Spectra and Theoretical Calculations

The UV/Vis spectra data of compounds 1–11 in solution

are summarized in Table S1 (Supporting Information).

Data of precursor complex 1 are also included for compari-

son. In CH₂Cl₂solution (10^–4m), mononuclear complexes

1–5 exhibit high-energy bands (range 250–380 nm), whose

Figure 7. View of the molecular structure of the cation of

[(C₆F₅)(bzq)(PPh₃)Pt(pyPh₂)]ClO₄(11).

Table 7. Selected bond lengths and angles for [{Pt(C₆F₅)(bzq)-

(PPh₃)}Ag (pyPh₂)]ClO₄·CH₂Cl₂(11·CH₂Cl₂).

1

intensities and shapes are typical of IL transitions (C₆F₅,

bzq) that are somewhat perturbed by the coordination of

platinum (see Figure 8 for complex 2).^[39,96,97]In addition,

they show a modest shoulder (ε = 1.0–2.1ϫ10³m^–1cm^–1)

centered at ca. 400 nm, which can generally be attributed to

¹MLCT/¹IL transitions. The UV/Vis spectra of complexes

1–5 recorded in different solvents show modest solvatochro-

mism (see Figure S3 in the Supporting Information for

complex 2) of the absorption bands, particularly in the

lower-energy spectral region, which is characteristic of CT

transitions.

Bond length [Å]

Pt–C(1)

Pt–N(1)

Pt–Ag

2.0140(13)

2.1143(11)

2.8147(1)

2.2929(14)

Pt–C(17)

Pt–P

Ag–N(2)

2.0633(15)

2.3286(4)

2.1898(12)

Ag–C(17)

Bond angle [°]

C(1)–Pt–C(17)

C(17)–Pt–N(1) 80.42(5)

C(17)–Pt–P

N(2)–Ag–Pt

92.64(6)

C(1)–Pt–N(1) 172.95(5)

C(1)–Pt–P

N(1)–Pt–P

89.90(4)

97.13(4)

173.14(4)

146.48(3)

The absorption spectra of heteronuclear complexes 6–11

This study confirms the presence of a donor–acceptor are all quite similar to those of their respective precursors

PtǞAg bond in the structure, with an intermetallic dis- 1–5 as much in the solid state as in solution (Tables 8 and

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dative bonds often show a blueshift in the low-energy ab-

sorption maxima; donation of electron density increases

electrophilicity of the Pt center, which lowers the energy of

the HOMO and raises the energy of the ¹MLCT absorption

bands.^[17,39]In complexes 6–11, little if any shift in the low-

energy absorption maxima with respect to those of the

starting compounds is observed. Similar behavior was pre-

viously observed in CH₂Cl₂solution of the trinuclear com-

plex (NBu₄)[{Pt(bzq)(C₆F₅)₂}₂Ag],^[17]which was explained

by the partial cleavage of the Pt–Ag bond in solution. How-

ever, this feature cannot be invoked in the solid state.

To better explain the nature of the lower-energy transi-

tions, TD-DFT calculations were carried out by using the

B3LYP hybrid density functional for 2, 4, and 5 and the

M06 hybrid density functional for 9, 10, and 11Me (11Me

is a model complex derived from complex 11 by replacing

the Ph groups with Me groups in the pyPh₂ligand to sim-

plify the calculation process). The geometric parameters of

the optimized S₀structures (Tables S2–S7, Supporting In-

formation) agree well with the experimental values. Rel-

evant data on the calculated lower-energy electronic transi-

tions in CH₂Cl₂and the frontier molecular orbitals (MOs)

involved in them are listed in Tables 10 and 11. In the mo-

nonuclear complexes, the HOMO is mostly constructed

from orbitals located on the bzq ligand (75% in 5 to 84%

in 2) and the platinum center (23% in 5 to 14% in 2). The

LUMO is well located on the imine ring (ca. 95%). Figure 8

shows that the calculated lowest-energy electronic transition

in CH₂Cl₂(bars) for compound 2 fits well, within the accu-

racy of the method, to the experimental absorptions. Calcu-

lations indicate that the major contribution to the lowest-

lying absorption involves the HOMOǞLUMO (94%)

Figure 8. Frontier orbital plots for complexes 2 and 11Me in

CH₂Cl₂obtained by DFT calculations; calculated electronic transi-

tions (bars) and experimental UV/Vis spectrum of 2 and 11 in transition, which is indicative of a remarkable ligand-cen-

CH₂Cl₂(10^–4m).

tered [¹IL, π–π* (bzq)] mixed with some metal-to-ligand

charge transfer [¹MLCT 5d(Pt)Ǟπ*(bzq)] character. Con-

trary to other benzoquinolate Pt^IIcomplexes de-

scribed,^[39,96,97]no ligand-to-ligand charge transfer

9, Figure 8; see also Table S1 and Figures S4 and S5 in the

Supporting Information). Complexes containing Pt–Ag

Table 8. Photophysical data for compounds 1–5 in the solid state.

[a] Emission was too week to be measured.

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Table 9. Photophysical data for compounds 6–11 in the solid state.

Table 10. Population analysis [%] of frontier MOs in the ground state for [Pt(C₆F₅)(bzq)L] [L = PPh₃(2), tht (4), MeCN (5)],

[(C₆F₅)(bzq)(PPh₃)PtAg(pyMe₂)]⁺(11Me), and [{Pt(C₆F₅)(bzq)L}₂Ag]⁺[L = tht (9) and MeCN (10)].

HOMO

LUMO

bzq

eV

Pt (1/2)

Ag

bzq

C₆F₅

L

eV

Pt (1/2)

Ag

C₆F₅

L

2

–5.68

–8.71

–5.71

–8.64

–5.59

–8.58

14

12

20

16/16

23

22/2

84

4

79

55

75

56

0

77

0

2

0

2

6

1

2

1

–1.84

–4.47

–1.88

–4.71

–1.86

–4.46

4

3

4

1/2

4

2/4

95

84

96

83

95

73

0

1

0

1

0

2

1

3

0

1

2

11Me

0

10

6

9

4

9

12

17

5

10

13

[¹LЈLCT, Ar_fǞbzq or LǞbzq] transitions are involved in

Calculations performed on trinuclear complexes 9 and 10

this absorption. In view of the data given in Tables 10 and show that the HOMO is constructed from orbitals located

11 and Figures S4 and S5 (Supporting Information), the on the bzq ligand (ca. 55%) and the platinum centers (32%

same assignments can be made for the lowest-lying absorp- for 9, 24% for 10) and with less weight from silver (10%

tion of compounds 4 and 5, but in these cases, the transition for 9, 6% for 10) and C₆F₅orbitals (2% for 9, 13% for 10).

1

shows slightly higher MLCT character. The blueshift ob- The LUMO is well located on the imine ring (83% for 9,

served in the calculated lowest-energy transition of 2 73% for 10) and the silver atom (12% for 9, 17% for 10).

(381 nm) in relation to that of the other mononuclear com- Therefore, it seems that the formation of two Pt–Ag bonds

plexes (382 nm for 4 and 386 nm for 5) can be due to the decreases the contribution from the bzq ligand and in-

lower energy level of the dπ(Pt) orbitals because of the elec- creases the metallic character (Pt/Ag) of the HOMO and

tron-withdrawing character of the PPh₃ligand with respect LUMO orbitals with respect to those of the starting com-

to those of the tht and MeCN ligands,^[98–101]as no signifi- plexes.

cant contribution of the L ligands to the frontier orbitals

was observed.

In dinuclear complex 11Me, the HOMO is mainly con-

structed from orbitals located on C₆F₅(77%) and the plati-

num center (12%) with no contribution from the atomic

orbitals of the silver atom and only a marginal contribution

from the bzq orbitals (4%). The LUMO is well located on

the imine ring (84%) with only a small metallic character

(3% Pt, 9% Ag). Therefore, the formation of a Pt–Ag bond

in 11Me changes dramatically the composition of the fron-

tier orbitals, especially that of the HOMO, by decreasing

the weight of the bzq orbitals and increasing those of the

electron-withdrawing C₆F₅group, as it was observed pre-

viously for the dinuclear [{Pt(bzq)(C₆F₅)₂}AgL] (L = PPh₃,

tht) complexes.^[39]Taking into account that the lowest-en-

Table 11. Selected singlet excited states calculated by TD-DFT for

complexes 2, 4, 5, 9, 10, and 11Me in CH₂Cl₂solution; o.s. = oscil-

lator strength.

λ_exc(calcd.)

o.s.

Transition

(% contribution)

[nm]

2

381.2

369.3

382.2

405.2

386.9

385.3

0.0524

0.0695

0.0610

0.0516

0.0577

0.0342

HOMOǞLUMO (94.4)

HOMOǞLUMO (94.5)

HOMOǞLUMO (94.0)

HOMOǞLUMO (94.5)

HOMOǞLUMO (94.8)

HOMOǞLUMO (85.8)

11Me

4

9

5

10

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ergy electronic absorption of each one of these heteronuc- solid state at room temperature (Figure 10, bottom), which

lear complexes is associated with a HOMOǞLUMO tran- shows that, in general, the presence of Pt–Ag dative bonds

sition (Table 11), it could be ascribed to ¹ILCT/ ¹MMЈLCT in heteronuclear compounds dramatically enhances the

[π–π*(bzq)]/{d/s(Pt,Ag)}Ǟπ*(bzq)] for 9 and 10 and to emission intensity when compared to that of their Pt^IIstart-

1

mixed MLCT/¹LЈLCT [MLCT 5d(Pt)Ǟπ*(bzq)]/[LЈLCT, ing complexes.

Ar_fǞbzq] for 11Me. Therefore, the formation of Pt–Ag

bonds leads to the stabilization of the HOMO and LUMO

orbitals and to a change in the nature of the electronic tran-

sitions; however, this has little effect on the energy of the

transitions, and the transitions are not always shifted to

higher energies.

The diffuse reflectance UV/Vis spectra of complexes 1–

11 in the solid state exhibit similar profiles to those in solu-

tion (see Figure S6 in the Supporting Information for 1–

5). Therefore, the same origin of the absorptions can be

presumed. This indicates that the π···π interactions ob-

served in the solid state (see parts b in Figures 2 and 4, see

also Figures S1 and S2 in the Supporting Information) have

a very small effect, if any, in the lowest-energy absorption

maxima except for complex 3, for which this absorption

appears redshifted relative to that of the other mononuclear

complexes.

Emission Spectra

Complexes 1–5 are scarcely emissive in the solid state at

room temperature but become brightly emissive at 77 K;

they exhibit an asymmetric yellow emission whose exci-

tation spectrum resembles the absorption one (see Table 8

and Figure 9 for complex 4). Emission lifetimes are rather

long and always fit to two components, as observed in many

benzoquinolate Pt^IIcomplexes.^[97]Therefore, the phospho-

3

rescent emission can be ascribed to an admixture of IL/

³MLCT excited states, probably with remarkable IL char-

acter, especially for complex 2.

3

Figure 10. Top: Unnormalized emission spectra of 1–5 in the solid

sate at 298 K. Bottom: Unnormalized emission spectra of 6–11 in

the solid state at 298 K; insets: compounds 2, 8, and 11 at 298 K

upon excitation at λ = 365 nm.

At 298 K, heteronuclear compounds 6–11 (Table 9 and

Figure 10, bottom) exhibit a yellow-green (λ_max= 530 nm

for 7, λ_max= 519 nm 11), yellow (λ_max= 551 nm for 9, λ_max

= 562 nm for 10), and yellow-orange (λ_max= 581 nm for

6, λ_max= 584 nm for 8) phosphorescence, which is clearly

enhanced upon cooling to 77 K.

Compounds

7

and 11, which contain the

“Pt(bzq)(C₆F₅)(PPh₃)” fragment, have very similar emis-

sion spectra at 298 K (Figure 10, bottom) and also at 77 K

(Figure 11). Taking into account the TD-DFT calculations

performed for compound 11Me and the emission behavior

described previously for [{Pt(bzq)(C₆F₅)₂}Ag(PPh₃)],^[39]the

emission band observed at 298 K can mainly arise from a

mixed ³MLCT/³LЈLCT excited state. At 77 K, the emission

Figure 9. Normalized excitation and emission spectra of 4 in the

solid state at 77 K.

Notably, at 298 K only compound 2 is moderately emis- clearly resolves into two bands: a weaker high-energy (HE)

sive (Figure 10, top). The emission (and excitation) profile emission at ca. 490 nm and an intense, broad, asymmetrical

of 2 is similar to that observed at 77 K and arises mainly low-energy (LE) band (λ_max= 591 nm for 7, λ_max= 565 nm

from excited states originating in the monomer species. for 11) with its maximum clearly redshifted with respect to

However, in compounds 1 and 3–5, the weak emission that at 298 K. The HE emission, which resembles the emis-

seems to come from barely emissive aggregates.^[18,102]By sion of the corresponding precursor, can be tentatively as-

3

contrast, heteronuclear compounds 6–11 are emissive in the signed to the IL/³MLCT excited state.

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which could be attributed to a bigger deformation of the

excited-state geometry in CH₂Cl₂at 77 K. The increasing

intensity of the low-energy band with respect to the higher-

energy bands with increasing concentration (from 10^–5m to

10^–3m) added to the redshift in its maximum (see Figure 12

for compound 4), which suggests that emissive ground-state

aggregates resulting from close π···π intermolecular con-

tacts could be not completely excluded at higher concentra-

tions. The emission spectra of the heteronuclear compounds

in a rigid matrix of CH₂Cl₂(10^–3m, 77 K, for 7–9 and 11)

showed similar profiles to those in the solid state at 77 K;

therefore, the same origin can be presumed for these bands.

Conclusions

Figure 11. Normalized emission spectra of 2, 7, and 11 in the solid

state at 77 K. Inset: Images of compounds 7 and 11 at 77 K upon

excitation at λ = 365 nm.

Despite its neutral character, [Pt(C₆F₅)(bzq)L] (L =

Me₂CO, PPh₃, pyPh₂, tht, MeCN) complexes have proven

to be suitable precursors for the preparation of complexes

containing Pt–Ag dative bonds. The bzq ligand seems to

play an important role in the stabilization of the heteropoly-

nuclear complexes formed in a twofold way. First, being a

strong-field ligand, bzq raises the energy of the d_z₂platinum

orbital and favors the formation of stronger PtǞAg dative

bonds. Second, in these complexes the silver centers estab-

lish short η¹interactions with the C_ipsoatom of the bzq

ligand, which contribute to fulfil the electron density

requirements of the acidic silver center. Nevertheless, only

trimetallic “sandwich” [{Pt(C₆F₅)(bzq)L}₂Ag]⁺complexes

can be prepared, even if other Pt/Ag ratios are used. There-

fore, it seems that the silver center “needs” to be surrounded

by two [Pt(C₆F₅)(bzq)L] subunits, with their corresponding

Pt–Ag and Ag–C_ipsointeractions. This is in contrast to the

[{Pt(bzq)(C₆F₅)₂}Ag(L)] and [{Pt(bzq)(C₆F₅)₂}Ag]_xcom-

plexes, for which the Pt/Ag ratio is 1:1, obtained from the

[Pt(bzq)(C₆F₅)₂]^–anion, in which, in principle, the Pt center

has an excess amount of electron density. Only in one case

was the 1:1 [(C₆F₅)(bzq)(PPh₃)PtAg(pyPh₂)]ClO₄(11)

product observed, and its relative stability was caused by

the presence of bulkier ligands that slow down its transfor-

mation into [{Pt(C₆F₅)(bzq)(PPh₃)}₂Ag]ClO₄(7).

The emission spectra of trinuclear compounds 6 and 8–

10 at 77 K show a profile that is similar to that of com-

pound 7, but their maxima are shifted to lower energies

(λ_max= 597 nm for 6, λ_max= 638 nm for 8, λ_max= 607 nm

for 9, λ_max= 601 nm for 10; see Figure S7 in the Supporting

Information for complex 10). TD-DFT calculations per-

formed on complexes 9 and 10 show an important contri-

bution from the metallic orbitals (Pt/Ag) to the frontier or-

bitals along with a small contribution from the C₆F₅orbit-

als. Because of this, it seems plausible to assign the more

intense LE band observed in the spectra of 8–10 to a

³MMЈLCT/³ILCT emissive state.

Complexes 1–11 are emissive in a rigid matrix of CH₂Cl₂

(10^–3m) at 77 K (Table S8, Supporting Information). Com-

pounds 1–5 show several emissions upon excitation in the

range 350–400 nm. They show low-intensity bands between

460 and 525 nm and a high-intensity asymmetric band cen-

tered at ca. 600 nm with a tail to 700 nm. 2-Methyltetra-

hydrofuran glassy solutions of 1–5 show similar profiles. At

low concentration (10^–5m), the low-energy band shows sim-

ilar energy and lifetime but a different profile to that in the

solid state at 77 K (see Figures 9 and 12 for complex 4),

Moreover, [{Pt(C₆F₅)(bzq)L}₂Ag]⁺complexes are flexi-

ble and are able to adapt their geometry (to some extent)

to the bulkiness of the ancillary L ligands to preserve, at

the same time, the Pt–Ag and Ag–C_ipsointeractions.

The photophysical properties of these complexes were

discussed with the aid of TD-DFT calculations on several

compounds (i.e., 2, 4, 5, 9, 10, and 11Me in CH₂Cl₂). In

the mononuclear complexes the lower-lying absorption

bands are ascribed to mixed [¹IL, π–π* (bzq)]/[¹MLCT

5d(Pt)Ǟπ*(bzq)] transitions, whereas in the hetero-

nuclear compounds, the formation of Pt–Ag bonds changes

the character of the transition to ¹ILCT/¹MMЈLCT

[π–π*(bzq)]/{d/s(Pt,Ag)}Ǟπ*(bzq)] for the trinuclear

complexes and to mixed ¹MLCT/¹LЈLCT [MLCT

5d(Pt)Ǟπ*(bzq)]/[LЈLCT, Ar_fǞbzq] for dinuclear com-

plex 11. However, although the formation of the Pt–Ag

Figure 12. Emission spectra of 4 in CH₂Cl₂(77 K) at λ_exc= 400 nm. bonds perturbs the frontier orbitals, it does not always shift

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the HOMOǞLUMO transition to higher energies. With

the exception of compound 2, the mononuclear complexes

are not emissive in the solid sate at room temperature. How-

ever the heteronuclear compounds are. All compounds be-

come brightly emissive in the solid state at 77 K. For all

compounds, the main phosphorescent emission has been

tentatively associated with a transition similar in character

to their lowest-lying absorption.

[Pt(C₆F₅)(bzq)(pyPh₂)] (3): Yield 0.220 g, 85%. C₃₆H₂₁F₅N₂Pt

(771.65): calcd. C 56.03, H 2.74, N 3.63; found C 55.88, H 2.86, N

3.52. IR: ν = 1497 (w), 1448 (m), 1435 (w), 1056 (w), 951 (m), 793

˜

Experimental Section

(m, C₆F₅, X-sensitive vibr.),^[103]696 (m, υ_py

) cm^–1. Λ_M(Me₂CO)

PPh₂

1

= 5.66 Ω^–1cm²mol^–1. H NMR ([D₆]Me₂CO, 295 K): δ = 8.67 (m,

Physical Measurements: C, H, and N analyses, conductivity, and

IR and NMR spectra were performed as described elsewhere.^[16]

¹H, ¹⁹F, and ³¹P NMR spectra were recorded at 400, 376.5, and

162.0 MHz, respectively. Diffuse reflectance UV/Vis (DRUV) spec-

tra were recorded with a Thermo electron corporation evolution

600 spectrophotometer equipped with a Praying Mantis integrating

sphere. The solid samples were homogeneously diluted with silica.

The mixtures were placed in a homemade cell equipped with quartz

window. Steady-state photoluminescence spectra were recorded

with a Jobin–Yvon Horiba Fluorolog FL-3–11 Tau 3 spectrofluor-

ometer by using a slit width of 3 nm for both excitation and emis-

sion. Phosphorescence lifetimes were recorded with a Fluoromax

phosphorimeter accessory containing a UV xenon flash tube with

a flash rate between 0.05 and 25 Hz. Phase shift and modulation

were recorded over the frequency range of 0.1–100 MHz. Nano-

second lifetimes were recorded with an IBH 5000F Coaxial nano-

second flashlamp. The lifetime data were fitted by using the Jobin–

Yvon software package and the Origin Pro 8 program. The quan-

tum efficiency was determined by using Quantaurus quantum yield

equipment from Hamamatsu model C11347-11.

³J_H2,H3= 5.30 Hz, H2), 8.64 (d, J_H4,H3= 8.10 Hz, J_H4,H2

=

3

4

1.20 Hz, H4), 8.26 (m, ³J_H= 7.09 Hz, ⁴J_H

= 1.50 Hz,

_meta,H_ortho

_para,H_ortho

4H-o-Ph), 7.98–7.86 (m, overlapped signals of 2H-m-py and H-p-

3

py), 7.85 (d, J_H5,H6= 8.80 Hz, H5), 7.78 (d, J_H6,H5= 8.80 Hz,

3

H6), 7.73 (m, overlapped with H2 and H4, H3), 7.56 (d, J_H7,H8

=

7.97 Hz, H7), 7.53 (m, ³J_H

4H-m-Ph), 7.46 (tt, ³J_H

= 7.45 Hz, ³J_H

= 1.40 Hz,

= 1.30 Hz,

_meta,H_ortho

_para,H_meta

= 7.28 Hz, ⁴J_H

_para,H_meta

_para,H_ortho

2H-p-Ph), 7.25 (dd, ³J_H8,H7= 7.66 Hz, ³J_H8,H9= 7.35 Hz, H8), 6.89

(dd, J_H9,H8= 7.35 Hz, J_H9,Pt= 74.1 Hz, H9) ppm. ¹⁹F NMR

(CD₂Cl₂, 295 K): δ = –119.04 (³J_F,Pt= 513 Hz, o-F), –166.61 (p-F,

t), 167.75 (m-F, br. m) ppm.

3

[Pt(C₆F₅)(bzq)(tht)] (4): Yield 0.214 g, 98%. C₂₃H₁₆F₅NPtS

(628.52): calcd. C 43.95, H 2.57, N 2.23, S 5.10; found C 44.08, H

2.32, N 2.33, S 5.10. IR: ν = 1501 (m), 1451 (m), 1437 (m), 1267

˜

(w, υ_SC), 1255 (w, υ_SC), 1061 (m), 951 (s), 798 (m, C₆F₅, X-sensitive

1

vibr.) cm^–1.^[103]Λ_M(Me₂CO) = 0.2 Ω^–1cm²mol^–1. H NMR ([D₆]-

Me₂CO, 295 K): δ = 9.35 (dd, ³J_H2,H3= 5.24 Hz, ⁴J_H2,H4= 1.31 Hz,

3

4

³J_H2,Pt= 23.4 Hz, H2), 8.70 (dd, J_H4,H3= 8.08 Hz, J_H4,H2

=

3

1.26 Hz, H4), 7.89 (d, J_H5,H6= 8.76 Hz, H5), 7.84 (dd, J_H3,H4

8.08 Hz, J_H3,H2= 5.26 Hz, H3), 7.80 (d, J_H6,H5= 8.75 Hz, H6),

3

Preparations: Literature methods were used to prepare the

[Pt(C₆F₅)(bzq)(Me₂CO)] (1) starting material.^[60]

3

4

7.63 (dd, J_H7,H8= 7.92 Hz, J_H7,H9= 0.70 Hz, H7), 7.34 (dd,

³J_H8,H9= 8.04 Hz, J_H8,H7= 7.31 Hz, H8), 6.82 (d, J_H9,H8

=

3

6.76 Hz, ³J_H9,Pt= 62.01 Hz, H9), 3.23 (m, 4H-m-tht), 1.87 (m, 4H-

Caution! Perchlorate salts of metal complexes with organic ligands

are potentially explosive. Only small amounts of material should be

prepared and these should be handled with great care.

o-tht) ppm. ¹⁹F NMR ([D₆]Me₂CO, 295 K): δ = –118.82 (³J_F,Pt

512.53 Hz, o-F), –166.09 (p-F), –166.90 (m-F, br. m) ppm.

=

Preparation of [Pt(C₆F₅)(bzq)L] [L = PPh₃(2), pyPh₂(3), tht (4)]:

To a solution of [Pt(bzq)(C₆F₅)(Me₂CO)] (1; 0.200g, 0.335 mmol)

in Me₂CO (10 mL) at 0 °C and under an Ar atmosphere was added

L (0.335 mmol; L = PPh₃, 0.0879 g; pyPh₂, 0.0775 g; tht, 30 μL).

After 2 min of stirring, the solution was concentrated to ca. 2 mL.

The yellow precipitate that appeared was filtered off, washed with

n-hexane (10 mL), and air dried.

Preparation

of

[Pt(C₆F₅)(bzq)(MeCN)]

(5):

Complex

[Pt(bzq)(C₆F₅)(Me₂CO)] (1) (0.200 g, 0.335 mmol) was dissolved in

MeCN (10 mL) at 0 °C under an Ar atmosphere. After 2 min of

stirring, the solution was evaporated to dryness. The yellow residue

was treated with n-hexane (10 mL), filtered, and finally air dried.

Yield 0.179 g, 92%. C₂₁H₁₁F₅N₂Pt (581.40): calcd. C 43.38, H 1.91,

N 4.82; found C 42.99, H 1.79, N 4.71. IR: ν = 2154 (vw, υ_CN),

˜

1497 (m), 1453 (m), 1062 (m), 953 (vs), 798 (m, C₆F₅, X-sensitive

vibr.) cm^–1.^[103]Λ_M(Me₂CO) = 7.01 Ω^–1cm²mol^–1. ¹H NMR ([D₆]-

Me₂CO, 295 K): δ = 9.19 (dd, ³J_H2,H3= 5.18 Hz, ⁴J_H4,H2= 1.20 Hz,

[Pt(C₆F₅)(bzq)(PPh₃)] (2): Yield 0.242 g, 90%. C₃₇H₂₂F₅NPPt

(801.63): calcd. C 55.37, H 2.89, N 1.75; found C 55.32, H 2.90, N

1.79. IR: ν = 1498 (w), 1458 (w), 1433 (w), 1096 (w, υ_PPh), 1058

˜

3

³J_H2,Pt= 21.78 Hz, H2), 8.65 (dd, J_H4,H3= 8.06 Hz, J_H4,H2

=

(w), 955 (m), 804 (m, C₆F₅, X-sensitive vibr.),^[103]693 (w), 529 (m),

3

1.20 Hz, H4), 7.85 (d, J_H5,H6= 8.83 Hz, H5), 7.75 (d, J_H6,H5

509 (m) cm^–1. Λ_M(Me₂CO) = 4.17 Ω^–1cm²mol^–1. H NMR ([D₆]-

1

3

8.83 Hz, H6), 7.74 (d, J_H3,H4= 8.46 Hz, J_H3,H2= 5.00 Hz, over-

Me₂CO, 295 K): δ = 8.55 (dd, ³J_H4,H3= 8.08 Hz, ⁴J_H4,H2= 1.25 Hz,

3

4

lapped with H6, H3), 7.58 (dd, J_H7,H8= 7.88 Hz, J_H7,H9

=

3

4

3

H4), 8.33 (dd, J_H2,H3= 5.35 Hz, J_H2,H4= 1.07 Hz, J_Pt,H2

=

3

0.60 Hz, H7), 7.30 (dd, J_H7,H8= 7.82 Hz, J_H7,H9= 7.62 Hz, H8),

26.85 Hz, H2), 7.93 (d, ³J_H5,H6= 8.72 Hz, H5), 7.78 (m, overlapped

with 6H-m-Ph and H7, H6), 7.78 (m, overlapped with 6H-m-Ph

and H6, H7), 7.78 (m, overlapped with H6 and H7, 6H-m-Ph), 7.51

6.96 (d, ³J_H9,H8= 7.62 Hz, ³J_H9,Pt= 58.51 Hz, H9), 2.61 (s, H_MeCN

)

ppm. ¹⁹F NMR ([D₆]Me₂CO, 295 K): δ = –119.08 (³J_F,Pt= 513 Hz,

o-F), –167.12 (p-F), 168.05 (m-F, br. m) ppm.

(m, J_H

= 7.50 Hz, J_H

= 1.60 Hz, 3H-p-Ph), 7.43 (m,

_para,H_meta

_para,H_ortho

overlapped with 6H-o-Ph, H8), 7.43 (m, overlapped with H8, 6H-

o-Ph), 7.23 (dd, J_H3,H4= 8.06 Hz, J_H3,H2= 5.37 Hz, H3), 7.00

Preparation of [{Pt(C₆F₅)(bzq)L}₂Ag]ClO₄[L = Me₂CO (6), PPh₃

(7), pyPh₂(8), tht (9)]: To a solution of [Pt(bzq)(C₆F₅)L] (L =

Me₂CO, 0.250 g, 0.418 mmol; L = PPh₃, 0.250 g, 0.187 mmol; L =

pyPh₂, 0.200 g, 0.260 mmol; L = tht, 0.200 g, 0.385 mmol) in

Me₂CO (20 mL) at 0 °C and under an Ar atmosphere was added

AgClO₄(L = Me₂CO, 0.043 g, 0.209 mmol; L = PPh₃, 0.019 g,

3

(dd, J_H9,H8= 7.26 Hz, J_H9,H7= 6.22 Hz, J_Pt,H9= 52.01 Hz, H9)

ppm. ¹⁹F NMR ([D₆]Me₂CO, 295 K): δ = –118.50 (³J_F,Pt

=

508.6 Hz, o-F), 167.94 (br. m, m-F), –168.37 (p-F) ppm. ³¹P NMR

([D₆]Me₂CO, 295 K): δ = 28.05 (s, J_P,Pt= 1982.2 Hz) ppm.

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0.093 mmol; L = pyPh₂, 0.0270 g, 0.130 mmol, L = tht, 0.040 g,

0.193 mmol). After 30 min of stirring in the absence of light, the

solution was concentrated to ca. 2 mL. Over the resultant yellow

suspension, n-hexane (10 mL) was added. The yellow precipitate

was filtered off and air dried.

Preparation of [{Pt(C₆F₅)(bzq)(MeCN)}₂Ag]ClO₄(10): To a solu-

tion of [Pt(bzq)(C₆F₅)(MeCN)] (0.200 g, 0.344 mmol) in Me₂CO

(20 mL) at 0 °C and under an Ar atmosphere was added AgClO₄

(0.0357 g, 0.172 mmol). After 30 min of stirring in the absence of

light, the solution was evaporated to dryness. The yellow residue

was treated with n-hexane (10 mL), filtered, and finally air dried.

Yield 0.211 g, 96%. C₄₂H₂₂AgClF₁₀N₄O₄Pt₂(1370.13): calcd. C

[{Pt(C₆F₅)(bzq)(Me₂CO)}₂Ag]ClO₄(6): Yield 0.154 g, 56%.

C₄₄H₂₈AgClF₁₀N₂O₆Pt₂(1404.18): calcd. C 37.64, H 2.01, N 2.00;

36.82, H 1.62, N 4.09; found C 37.17, H 2.02, N 3.73. IR: ν = 2165

˜

found C 37.87, H 2.11, N 1.99. IR: ν = 1620 (w), 1503 (w), 1455

˜

(vw, υ_CN), 1504 (m), 1443 (m), 1456 (m), 1060 (s), 1090 (m, υ

–

),

ClO₄

(w), 1442 (w), 1096 (m, υ_ClO), 1059 (m), 953 (m), 801 (m, C₆F₅,

–

4

953 (s), 804 (m, C₆F₅, X-sensitive vibr.),^[103]623 (m, υ_ClO

–

) cm^–1.

X-sensitive vibr.),^[103]621 (m, υ_ClO) cm^–1. Λ_M(Me₂CO) =

–

Λ_M(Me₂CO) = 225.67 Ω^–1cm²mol^–1. ¹H NMR ([D₆]⁴Me₂CO,

4

134.35 Ω^–1cm²mol^–1. ¹H NMR ((D₆)Me₂CO, 295 K): δ = 8.70 (dd,

3

4

3

295 K): δ = 9.17 (dd, J_H2,H3= 5.13 Hz, J_H2,H4= 1.06 Hz, J_H2,Pt

= 24.70 Hz, H2), 8.73 (dd, J_H4,H3= 8.18 Hz, J_H4,H2= 1.03 Hz,

H4), 7.89 (d, J_H5,H6= 8.74 Hz, H5), 7.87 (m, overlapped with H5

and H6, H3), 7.84 (d, J_H6,H5= 8.79 Hz, H6), 7.68 (d, J_H7,H8=

7.95 Hz, H7), 7.27 (dd, J_H8,H7= 7.75 Hz, J_H8,H9= 7.69 Hz, H8),

6.95 (d, J_H9,H8= 7.69 Hz, J_H9,Pt= 63.0 Hz, H9), 2.65 (s, H_MeCN

³J_H2,H3= 8.11 Hz, J_H2,H4= 1.14 Hz, H2), 8.64 (m, J_H4,H3

=

3

4

3

8.11 Hz, H4), 7.86 (m, H3, H5, and H6), 7.63 (dd, J_H7,H8

3

4

3

7.94 Hz, J_H7,H9= 0.52 Hz, H7), 7.19 (dd, J_H8,H7= 7.47 Hz,

3

³J_H8,H9= 7.58 Hz, H8), 6.90 (d, J_H9,H8= 7.06 Hz, J_H9,Pt

=

3

71.21 Hz, H9), 2.14 (s, H_{Me CO}) ppm. ¹⁹F NMR ([D₆]Me₂CO,

295 K): δ = –117.89 (³J_F,Pt= 5²02.3 Hz, o-F), –165.06 (p-F), –166.66

(br. m, m-F) ppm.

3

)

ppm. ¹⁹F NMR ([D₆]Me₂CO, 295 K): δ = –117.87 (³J_F,Pt

492.0 Hz, o-F), –165.81 (p-F), –167.14 (m-F, br. m) ppm.

=

[{Pt(C₆F₅)(bzq)(PPh₃)}₂Ag]ClO₄(7): Yield 0.132 g, 82%.

Preparation of [Pt(C₆F₅)(bzq)(PPh₃)Ag(pyPh₂)]ClO₄(11): To a

solution of [Pt(bzq)(C₆F₅)(pyPh₂)] (0.200 g, 0.259 mmol) in

Me₂CO (20 mL) at 0 °C and under an Ar atmosphere was added

[Ag(OClO₃)(PPh₃)] (0.121 g, 0.259 mmol). After 30 min of stirring

in the absence of light, the solution was evaporated to dryness. The

oily yellow residue was treated with n-hexane (10 mL) and allowed

to stir for 60 min. After this time, the yellow solid formed was fil-

tered off and air dried. Yield 0.263 g, 88%. C₅₄H₃₆AgClF₅N₂O₄PPt

(1241.25): calcd. C 52.25, H 2.92, N 2.26; found C 52.02, H 2.81,

C₇₄H₄₆AgClF₁₀N₂O₄P₂Pt₂(1812.60): calcd. C 49.03, H 2.56, N

1.55; found C 48.98, H 2.59, N 1.59. IR: ν = 1500 (m), 1458 (m),

˜

1435 (m), 1093 (m, υ_ClO), 1060 (m), 954 (s), 804 (s, C₆F₅, X-sensi-

–

4

tive vibr.),^[103]693 (s), 621 (m, υ_ClO

), 529 (s, υ_PPh), 509 (s, υ_PPh)

3 3

–

cm^–1. Λ_M(Me₂CO) = 266.06 Ω^–1cm⁴²mol^–1. ¹H NMR ([D₆]Me₂CO,

3

4

295 K): δ = 8.61 (dd, J_H4,H3= 8.05 Hz, J_H4,H2= 0.90 Hz, H4),

8.34 (d, ³J_H2,H3= 5.35 Hz, ³J_H2,Pt= 25.77 Hz, H2), 7.94 (d, ³J_H5,H6

3

= 8.72 Hz, H5), 7.82 (d, J_H6,H5= 8.74 Hz, H6), 7.74 (m, over-

3

4

lapped with 6H-m-Ph, H7), 7.53 (m, J_H

= 7.46 Hz, J_H

_para,H_meta

para,-

= 1.18 Hz, 3H-p-Ph), 7.45 (m, H8 and 6H-o-Ph), 7.29 (dd,

N 2.24. IR: ν = 1501 (w), 1456 (w), 1435 (w), 1092 (m, υ

–

), 1059

H_ortho

˜

ClO₄

3

³J_H3,H4= 8.05 Hz, J_H3,H2= 5.37 Hz, H3), 7.11 (t, J_H9,H8

=

(w), 957 (w), 803 (w, C₆F₅, X-sensitive vibr.), 621 (w, υ

–

), 693

ClO₄

3

6.22 Hz, J_H9,Pt= 49.30 Hz, H9) ppm. ¹⁹F NMR ([D₆]Me₂CO,

295 K): δ = –117.89 (³J_F,Pt= 504.3 Hz, o-F), –167.07, –167.54 (m-

F, p-F br. m) ppm. ³¹P NMR ([D₆]Me₂CO, 295 K): δ = 27.23 (s,

J_P,Pt= 2081.1 Hz) ppm.

(w), 531 (w), 512 (w) cm^–1. Λ_M(Me₂CO) = 246.87 Ω^–1cm²mol^–1.

3

¹H NMR ([D₆]Me₂CO, 295 K): δ = 8.64 (dd, J_H4,H3= 8.07 Hz,

3

³J_H4,H2= 1.0 Hz, H4), 8.34 (d, J_H2,H3= 5.36 Hz, J_H2,Pt

=

26.36 Hz, H2), 8.15 (m, 4H-o-Ph), 8.06 (m, H-p-py), 7.99 (d,

3

³J_H5,H6= 8.74 Hz, H5), 7.91 (m, 2H-m-py), 7.85 (d, J_H6,H5

=

[{Pt(C₆F₅)(bzq)(pyPh₂)}₂Ag]ClO₄(8): Yield 0.207 g, 96%.

8.87 Hz, H6), 7.74 [m, H7 and H-m-Ph (PPh₃)], 7.55–7.42 [m, H8

and 3H-p-Ph (PPh₃), 6H-o-Ph (PPh₃), 4H-m-Ph (PPh₂), 2H-p-Ph

C₇₂H₄₂AgClF₁₀N₄O₄Pt₂(1750.61): calcd. C 49.40, H 2.42, N 3.20;

found C 48.97, H 2.52, N 3.34. IR: ν = 1501 (w), 1452 (w), 1439

˜

3

4

(PPh₂)], 7.32 (dd, J_H3,H4= 8.06 Hz, J_H3,H2= 5.38 Hz, H6), 7.13

(w), 1093 (w, υ_ClO), 1058 (m), 953 (m), 797 (s, C₆F₅, X-sensitive

–

4

3

(t, J_H9,H8= 6.21 Hz, J_H2,Pt= 47.40 Hz, H9) ppm. ¹⁹F NMR

([D₆]Me₂CO, 295 K): δ = –116.93 (³J_F,Pt= 500.65 Hz, o-F), 167.16

(m-F, br. m), –166.88 (p-F) ppm. ³¹P NMR ([D₆]Me₂CO, 295 K):

δ = 26.59 (s, J_P,Pt= 2147.8 Hz) ppm.

vibr.),^[103]622 (w, υ_ClO), 696 (w) cm^–1. Λ_M(Me₂CO)

–

=

4

241.43 Ω^–1cm²mol^–1. ¹H NMR ([D₆]Me₂CO, 295 K): δ = 8.70 (dd,

4

³J_H2,H3= 8.12 Hz, J_H2,H4= 1.10 Hz, overlapped with H4, H2),

8.67 (m, overlapped with H2, H4), 8.02 (m, H-p-py), 8.15 (m, 4H-

o-Ph), 7.90 (m, 2H-m-py), 7.88 (d, ³J_H5,H6= 8.79 Hz, H5), 7.84 (d,

X-ray Structure Determinations: Crystal data and other details of

the structure analyses are presented in Tables 12 and 13. Suitable

crystals for X-ray diffraction studies were obtained by slow dif-

fusion of n-hexane into concentrated solutions of the complexes in

CH₂Cl₂or Me₂CO (3 mL). Crystals were mounted at the end of

quartz fibers. The radiation used in all cases was graphite mono-

3

4

³J_H6,H5= 8.85 Hz, H6), 7.63 (dd, J_H7,H8= 7.97 Hz, J_H7,H9

=

0.54 Hz, H7), 7.49 (m, 4H-m-Ph and 2H-p-Ph), 7.24 (dd, ³J_H8,H7

7.62 Hz, ³J_H8,H9= 7.45 Hz, H8), 6.89 (d, ³J_H9,H8= 7.28 Hz, ³J_H9,Pt

= 71.51 Hz, H9) ppm. ¹⁹F NMR ([D₆]Me₂CO, 295 K): δ = –118.26

(³J_F,Pt= 505.91 Hz, o-F), –165.50 (p-F), –166.94 (m-F, br. m) ppm.

[{Pt(C₆F₅)(bzq)(tht)}₂Ag]ClO₄

(9):

Yield

0.200 g,

71%. chromated Mo-K_α(λ = 0.71073 Å). X-ray intensity data were col-

C₄₆H₃₂AgClF₁₀N₂O₄Pt₂S₂(1464.37): calcd. C 37.73, H 2.20, N lected with an Oxford Diffraction Xcalibur diffractometer. The dif-

1.91, S 4.38; found C 37.29, H 2.01, N 1.92, S 3.89. IR: ν = 1503

(m), 1453 (m), 1439 (m), 1269 (w, υ_SC), 1256 (w, υ_SC), 1086 (m,

fraction frames were integrated and corrected from absorption by

using the CrysAlis RED program.^[104]The structures were solved

by Patterson and Fourier methods and refined by full-matrix least-

squares on F²with SHELXL-97.^[105]All non-hydrogen atoms were

assigned anisotropic displacement parameters and refined without

˜

υ_ClO

–

), 1061 (s), 952 (s), 801 (m, C₆F₅, X-sensitive vibr.),^[103]621

4

(w, υ_ClO

–

) cm^–1. Λ_M(Me₂CO) = 238.73 Ω^–1cm²mol^–1. ¹H NMR

4

3

4

([D₆]acetone, 295 K): δ = 9.26 (dd, J_H2,H3= 5.24 Hz, J_H2,H4

=

3

1.27 Hz, J_H2,Pt= 21.9 Hz, H2), 8.77 (dd, J_H4,H3= 8.10 Hz, positional constraints, except as noted below. All hydrogen atoms

⁴J_H4,H2= 1.21 Hz, H4), 7.93 (dd, J_H3,H4= 8.08 Hz, J_H3,H2

=

were constrained to idealized geometries and assigned isotropic dis-

placement parameters equal to 1.2 times the U_isovalues of their

3

5.23 Hz, H3), 7.91 (d, J_H5,H6= 8.74 Hz, H5), 7.86 (d, J_H6,H5

3

4

8.77 Hz, H6), 7.73 (dd, J_H7,H8= 8.00 Hz, J_H7,H9= 0.70 Hz, H7), attached parent atoms (1.5 times for the methyl hydrogen atoms).

7.34 (dd, ³J_H8,H9= 7.89 Hz, ³J_H8,H7= 7.20 Hz, H8), 6.86 (d, ³J_H9,H8

In the structure of 4·2/3CH₂Cl₂, three complete complexes are

3

= 7.03 Hz, J_H9,Pt= 58.53 Hz, H9), 3.17 (m, 4H-m-tht), 1.86 (m, found in the asymmetric unit. In two of them, the β CH₂fragments

4H-o-tht) ppm. ¹⁹F NMR ([D₆]Me₂CO, 295 K): δ = –117.47 (³J_F,Pt

= 506.05 Hz, o-F), –164.62 (p-F), –165.86 (m-F, br. m) ppm.

of the tht ligands are disordered over two positions, which were

refined with partial occupancy 0.60/0.40 and 0.65/0.35. Weak re-

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straints were applied in the interatomic C–C distances and thermal

parameters of these fragments. For 10·2.5CH₂Cl₂·0.5n-C₆H₁₄, re-

straints were used in some structural and thermal parameters of

the C atoms of the bzq ligands. Very diffuse solvent was found

during the refinement stages and was modeled as several CH₂Cl₂

moieties, some of them disordered, with a total occupancy of 2.5,

and half of an n-hexane molecule. Restrains were used in the struc-

tural and thermal parameters of these units.

Table 12. Crystal data and structure refinement for [Pt(C₆F₅)-

(bzq)(PPh₃)]·0.2Me₂CO (2·0.2Me₂CO), [Pt(C₆F₅)(bzq)(tht)]·

2/3CH₂Cl₂(4·2/3CH₂Cl₂), and [Pt(C₆F₅)(bzq)(MeCN)] (5).

2·0.2Me₂CO

4·2/3CH₂Cl₂

5

Formula

C₃₇H₂₃F₅NPPt·

0.2Me₂CO

814.24

C₂₃H₁₆F₅NPtS· C₂₁H₁₁F₅N₂Pt

2/3CH₂Cl₂

Formula weight

Crystal system

Space group

a [Å]

b [Å]

c [Å]

685.14

monoclinic

Pc

581.41

monoclinic

P2₁/c

triclinic

¯

Full-matrix least-squares refinement of these models against F²

converged to final residual indices given in Tables 12 and 13.

CCDC-906692 (for 2), -906693 (for 4), -906694 (for 5), -906695 (for

7), -906696 (for 9), -906697 (for 10), and -906698 (for 11) contain

the supplementary crystallographic data for this paper. These data

can be obtained free of charge from The Cambridge Crystallo-

graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.

P1

14.3213(3)

14.7249(4)

16.0887(5)

80.101(3)

79.902(2)

66.437(2)

3042.17(14)

4

1.778

100(1)

4.726

1586

16.1169(3)

12.4389(2)

16.4671(3)

90

13.851(2)

7.4016(7)

17.653(2)

90

α [°]

β [°]

93.036(2)

90

108.066(14)

90

γ [°]

V [Å³]

3296.63(10)

6

12406.2(7)

4

Z

Computational Methods: DFT calculations were performed by

using the hybrid functionals B3LYP^[106,107]for complexes 2, 4, and

5 and M06^[108]for complexes 9, 10, and 11Me under the Gaussian

09 package.^[109]The SDD pseudopotential and associated basis

set^[110]was used for platinum and silver atoms, and the 6-31G(d)

D_c[gcm^–3]

T [K]

2.071

2.245

100(1)

6.697

100(1)

8.217

μ (Mo-K_α) [mm^–1]

F(000)

1968

1096

θ range [°]

Reflections

collected

Independent

reflections

R_int

4.2–26.0

28562

4.2–28.9

34078

4.1–25.5

11311

[111,112]

basis set was used for all other atoms. Geometry optimiza-

tions were performed under no symmetry restrictions by using ini-

tial coordinates derived from X-ray data of the same or comparable

complexes. Frequency calculations were used to confirm the sta-

tionary points were true minima. TD-DFT calculations were per-

formed by using the polarized continuum model approach im-

plemented in the Gaussian 09 software. A Mulliken population

analysis was included for interpretation purposes. Molecular orbit-

als were visualized by using the Molekel program package.^[113]

11905

14799

3170

0.0292

0.0425

0.0601

R₁, wR₂^[a][IϾ2σ(I)] 0.0426, 0.0826

0.0364, 0.0908 0.0416, 0.0988

0.0413, 0.0926 0.0525, 0.1026

1.030

R₁, wR₂^[a](all data)

GOF (F²)^[b]

Absolute

0.0536, 0.0849

1.122

–

1.030

–

0.020(5)

structure par.

2

2 2

[a] R₁= Σ(|F_o| – |F_c|)/Σ|F_o|. wR_{2 2}=₂[Σw(F_o– F_c) /Σw(F_o²)²]^1/2

.

Supporting Information (see footnote on the first page of this arti-

cle): Absorption data of solutions of 1–11 at room temperature;

[b] Goodness-of-fit = [Σw(F_o– F_c) /(n_obsd.– n_param.)]^1/2

.

2

Table 13. Crystal data and structure refinement for [{Pt(C₆F₅)(bzq)(PPh₃)}₂Ag]ClO₄·CH₂Cl₂(7·CH₂Cl₂), [{Pt(C₆F₅)(bzq)(tht)}₂Ag]-

ClO₄·1.5Me₂CO (9·1.5Me₂CO), [{Pt(C₆F₅)(bzq)(MeCN)}₂Ag]ClO₄·2.5CH₂Cl₂·0.5n-C₆H₁₄(10·2.5CH₂Cl₂·0.5n-C₆H₁₄), and [(C₆F₅)(bzq)-

(PPh₃)Pt(pyPh₂)]ClO₄·CH₂Cl₂(11·CH₂Cl₂).

7·CH₂Cl₂

9·1.5Me₂CO

10·2.5CH₂Cl₂·0.5n-C₆H₁₄11·CH₂Cl₂

Formula

C₇₄H₄₆AgClF₁₀N₂O₄P₂Pt₂· C₄₆H₃₂AgClF₁₀N₂O₄Pt₂S₂· C₄₂H₂₂AgClF₁₀N₄O₄Pt₂· C₅₄H₃₆AgClF₅N₂O₄PPt·

CH₂Cl₂

1897.49

monoclinic

P2₁/c

13.1438(2)

35.7903(8)

14.3105(3)

90

102.9667(19)

90

6560.3(2)

4

1.5Me₂CO

1551.47

2.5CH₂Cl₂·0.5n-C₆H₁₄

1625.54

CH₂Cl₂

1326.15

triclinic

M_t

Crystal system

Space group

a [Å]

b [Å]

c [Å]

α [°]

β [°]

triclinic

¯

P1

13.5673(8)

14.4385(11)

15.3982(8)

72.599(6)

68.987(5)

64.745(7)

2508.2(3)

2

13.9756(4)

14.3662(3)

16.1823(3)

79.6218(17)

69.783(2)

64.539(2)

2750.84(11)

2

13.4888(2)

13.5126(2)

14.6245(2)

106.249(1)

107.091(1)

90.684(1)

2433.18(6)

2

γ [°]

V [Å³]

Z

D_c[gcm^–3]

T [K]

1.921

100(1)

2.052

100(1)

1.963

100(1)

1.810

100(1)

μ [mm^–1]

F(000)

4.804

3672

6.175

1485

5.796

1548

3.542

1300

θ range [°]

Reflections collected

Independent reflections 15626

4.2–28.9

57416

4.3–28.9

49929

11819

4.1–28.9

58605

13069

4.2–35.3

91933

18524

R_int

0.0427

0.0600

0.0624

0.0286

[a]

R₁, wR_2[a][IϾ2σ(I)]

R₁, wR₂(all data)

GOF (F²)^[b]

0.0347, 0.0566

0.0531, 0.0586

1.008

0.0395, 0.0997

0.0569, 0.1070

1.044

0.0571, 0.1524

0.0942, 0.1646

1.030

0.0190, 0.0419

0.0244, 0.0425

1.027

[a] R₁= Σ(|F_o| – |F_c|)/Σ|F_o|. wR₂= [Σw(F_o– F_c) /Σw(F_o²)²]^1/2. [b] Goodness-of-fit = [Σw(F_o– F_c) /(n_obsd.– n_param.)]^1/2

.

2

2 2

2

2 2

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[26]

D. E. Janzen, L. F. Mehne, D. G. VanDerveer, G. J. Grant, In-

org. Chem. 2005, 44, 8182.

S. A. Baudron, M. W. Hosseini, Chem. Commun. 2008, 4558.

G.-Q. Yin, Q.-H. Wei, L.-Y. Zhang, Z.-N. Chen, Organometal-

lics 2006, 25, 580.

M.-E. Moret, P. Chen, Organometallics 2008, 27, 4903.

L. R. Falvello, J. Forniés, R. Garde, A. García, E. Lalinde,

M. T. Moreno, A. Steiner, M. Tomás, I. Usón, Inorg. Chem.

2006, 45, 2543.

O. Crespo, A. Laguna, E. J. Fernández, J. M. López de Luzuri-

aga, P. G. Jones, M. Teichert, M. Monge, P. Pyykkö, N. Runeb-

erg, M. Schütz, H. J. Werner, Inorg. Chem. 2000, 39, 4786.

S. Fuertes, C. H. Woodall, P. R. Raithby, V. Sicilia, Organome-

tallics 2012, 31, 4228.

L. R. Falvello, J. Forniés, A. Martín, V. Sicilia, P. Villarroya,

Organometallics 2002, 21, 4604.

E. Alonso, J. Forniés, C. Fortuño, A. Martín, A. G. Orpen,

Organometallics 2003, 22, 5011.

F. D. Rochon, R. Melanson, Acta Crystallogr., Sect. C: Cryst.

Struct. Commun. 1988, 44, 474.

L. R. Falvello, J. Forniés, C. Fortuño, F. Durán, A. Martín,

Organometallics 2002, 21, 2226.

I. Ara, L. R. Falvello, J. Forniés, J. Gómez, E. Lalinde, R. I.

Merino, I. Usón, J. Organomet. Chem. 2002, 663, 284.

L. R. Falvello, J. Forniés, E. Lalinde, B. Menjón, M. A.

García Monforte, M. T. Moreno, M. Tomás, Chem. Commun.

2007, 3838.

J. Forniés, S. Ibáñez, E. Lalinde, A. Martín, M. T. Moreno,

A. C. Tsipis, Dalton Trans. 2012, 41, 3439.

P. T. Chou, Y. Chi, Chem. Eur. J. 2007, 13, 380.

M. W. Cooke, G. S. Hanan, Chem. Soc. Rev. 2007, 36, 1466.

R. C. Evans, P. Douglas, C. J. Wiscom, Coord. Chem. Rev.

2006, 250, 2093.

E. Holder, B. M. W. Langeveld, U. S. Schubert, Adv. Mater.

2005, 17, 1109.

M. D. McClenaghan, N. D. Leydet, Y. Maubert, M. T. Indelli,

S. Campagna, Coord. Chem. Rev. 2005, 249, 1336.

S. S. Sun, A. J. Lees, Coord. Chem. Rev. 2002, 230, 171.

W. Y. Wong, Comments Inorg. Chem. 2005, 26, 39.

M. H. V. Huynh, D. M. Dattelbaum, T. J. Meyer, Coord. Chem.

Rev. 2005, 249, 457.

DFT-optimized coordinates and selected singlet excited states cal-

culated by TD-DFT for complexes 2, 4, 5, 9, 10, and 11Me in

CH₂Cl₂; emission data of solutions of 1–5 at 77 K; views of the

supramolecular arrangement showing π···π stacking for complexes

2 and 5; normalized absorption spectra of 2 in solutions of different

solvents at room temperature; energy levels and electron-density

diagrams of the frontier molecular orbitals involved in the lower-

energy excited calculated states for 4, 5, 9, and 10; normalized

DRUV spectra of complexes 1–5 in the solid state; and normalized

emission and excitation spectra of 5 and 10 in the solid state.

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

[35]

[36]

[37]

[38]

Acknowledgments

This work was supported by the Spanish Ministerio de Ciencia e

Innovación (MICINN) (DGPTC/FEDER) (project number

CTQ2008-06669-C02-01/BQU). The authors thank Mariano

Perálvarez (IREC) for the QY measurements. We thank CESGA

(Supercomputing Centre of Galicia, Santiago de Compostela,

Spain) for the supercomputing facilities.

[1] P. Pyykkö, Chem. Rev. 1997, 97, 597.

[2] P. Pyykkö, Angew. Chem. 2004, 116, 4512; Angew. Chem. Int.

Ed. 2004, 43, 4412.

[3] L. H. Gade, Angew. Chem. 2001, 113, 3685; Angew. Chem. Int.

Ed. 2001, 40, 3573.

[4] M. A. Carvajal, S. Álvarez, J. J. Novoa, Chem. Eur. J. 2004, 10,

2117.

[39]

[40]

[41]

[42]

[5] A. Díez, E. Lalinde, M. T. Moreno, Coord. Chem. Rev. 2011,

255, 2426.

[6] E. J. Fernández, A. Laguna, J. M. López de Luzuriaga, Dalton

Trans. 2007, 1969.

[7] E. J. Fernández, A. Laguna, J. M. López de Luzuriaga, Coord.

Chem. Rev. 2005, 249, 1423.

[8] A. Laguna (Ed.), Modern Supramolecular Gold Chemistry,

Wiley-VCH, Weinheim, 2008.

[9] E. J. Fernández, J. M. López de Luzuriaga, M. Monge, M. A.

Rodríguez, O. Crespo, M. C. Gimeno, A. Laguna, P. G. Jones,

Chem. Eur. J. 2000, 6, 636.

[43]

[44]

[45]

[46]

[47]

[10] V. W. W. Yam, E. C. C. Cheng, Chem. Soc. Rev. 2008, 37, 1806.

[11] H. Schmidbaur, A. Schier, Chem. Soc. Rev. 2008, 37, 1931.

[12] S. Sculfort, P. Braunstein, Chem. Soc. Rev. 2011, 40, 2741.

[13] J. Forniés, A. Martín in Metal Clusters in Chemistry (Eds.: P.

Braunstein, L. A. Oro, P. R. Raithby), Wiley-VCH, Weinheim,

1999, vol. 1, pp. 417.

[14] J. Forniés, C. Fortuño, S. Ibáñez, A. Martín, Inorg. Chem.

2008, 47, 5978.

[15] J. Forniés, S. Fuertes, A. Martín, V. Sicilia, B. Gil, E. Lalinde,

Dalton Trans. 2009, 2224.

[48]

[49]

A. Vogler, H. Kunkely, Top. Curr. Chem. 2001, 213, 143.

P. Thanasekaran, R. T. Liao, Y. H. Liu, T. Rajendran, S. Rajag-

opal, K. L. Lu, Coord. Chem. Rev. 2005, 249, 1085.

Special issue on the “Thirteenth International Symposium on

Photochemistry and Photophysics of Coordination Com-

pounds (ISPPCC)”: Coord. Chem. Rev. 2000, 208.

B. Ma, P. I. Djurovich, M. E. Thompson, Coord. Chem. Rev.

2005, 249, 1501.

S. Pérez, C. López, A. Caubet, R. Bosque, X. Solans, M. F.

Bardía, A. Roig, E. Molins, Organometallics 2004, 23, 224.

J. Forniés, V. Sicilia, J. M. Casas, A. Martín, J. A. López, C.

Larraz, P. Borja, C. Ovejero, Dalton Trans. 2011, 40, 2898.

R. Usón, J. Forniés, M. Tomás, I. Ara, J. M. Casas, A. Martín,

J. Chem. Soc., Dalton Trans. 1991, 2253.

L. R. Falvello, J. Forniés, A. Martín, V. Sicilia, P. Villarroya,

Organometallics 2002, 21, 4604.

I. Ara, J. Forniés, V. Sicilia, P. Villarroya, Dalton Trans. 2003,

4238.

J. R. Berenguer, B. Gil, J. Fernández, J. Forniés, E. Lalinde,

Inorg. Chem. 2009, 48, 5250.

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[16] J. Forniés, S. Ibáñez, A. Martín, B. Gil, E. Lalinde, M. T. Mor-

eno, Organometallics 2004, 23, 3963.

[17] J. Forniés, S. Ibáñez, A. Martín, M. Sanz, J. R. Berenguer, E.

Lalinde, J. Torroba, Organometallics 2006, 25, 4331.

[18] J. R. Berenguer, A. Díez, J. Fernández, J. Forniés, A. García,

B. Gil, E. Lalinde, M. T. Moreno, Inorg. Chem. 2008, 47, 7703.

[19] J. M. Casas, J. Forniés, S. Fuertes, A. Martín, V. Sicilia, Orga-

nometallics 2007, 26, 1674.

[20] W. Chen, F. Liu, T. Nishioka, K. Matsumoto, Eur. J. Inorg.

Chem. 2003, 4234.

[21] A. Díez, J. Forniés, J. Gómez, E. Lalinde, A. Martín, M. T.

Moreno, S. Sánchez, Dalton Trans. 2007, 3653.

[22] T. Yamaguchi, F. Yamazaki, T. Ito, J. Am. Chem. Soc. 1999,

121, 7405.

C. Mealli, F. Pichierri, L. Randaccio, E. Zangrando, M.

Krumm, D. Holtenrich, B. Lippert, Inorg. Chem. 1995, 34,

3418.

G. Aullón, S. Álvarez, Inorg. Chem. 1996, 35, 3137.

J. R. Berenguer, E. Lalinde, M. T. Moreno, S. Sánchez, J. Tor-

roba, Inorg. Chem. 2012, 51, 11665.

[59]

[60]

[23] T. Yamaguchi, F. Yamazaki, T. Ito, J. Am. Chem. Soc. 2001,

123, 743.

[24] M.-E. Moret, P. Chen, J. Am. Chem. Soc. 2009, 131, 5675.

[25] G. Kampf, P. J. S. Miguel, M. Willermann, A. Schneider, B.

Lippert, Chem. Eur. J. 2008, 14, 6882.

[61]

J. Forniés, J. Gómez, E. Lalinde, M. T. Moreno, Inorg. Chem.

2001, 40, 5415.

Eur. J. Inorg. Chem. 0000, 0–0

16

Job/Unit: I21528

/KAP1

Date: 12-02-13 10:38:59

Pages: 18

www.eurjic.org

FULL PAPER

[62] S. Fuertes, S. K. Brayshaw, P. R. Raithby, S. Schiffers, M. R.

Warren, Organometallics 2012, 31, 105.

[91] R. M. Hellyer, D. S. Larsen, S. Brooker, Eur. J. Inorg. Chem.

2009, 1162.

[92] L.-C. Song, G.-X. Jin, L.-Q. Zhao, H.-T. Wang, W.-X. Zhang,

Q.-M. Hu, Eur. J. Inorg. Chem. 2009, 419.

[63] C. A. Hunter, J. K. M. Sanders, J. Am. Chem. Soc. 1990, 112,

5525.

[64] C. A. Hunter, Chem. Soc. Rev. 1994, 23, 101.

[65] A. Díez, J. Forniés, A. García, E. Lalinde, M. T. Moreno, In-

org. Chem. 2005, 44, 2443.

[66] W. Lu, M. C. W. Chan, N. Zhu, C. M. Che, C. Li, Z. Hui, J.

Am. Chem. Soc. 2004, 126, 7639.

[67] V. W. Yam, R. P. L. Tang, K. M. C. Wong, X. X. Lu, K. K.

Cheung, N. Zhu, Chem. Eur. J. 2002, 8, 4066.

[68] S. J. Farley, D. L. Rochester, A. L. Thompson, J. A. K. How-

ard, J. A. Williams, Inorg. Chem. 2005, 44, 9690.

[93] R. P. Feazell, C. E. Carson, K. K. Klausmeyer, Inorg. Chem.

2006, 45, 935.

[94] N. Sadhukhan, S. K. Patra, K. Sana, J. K. Bera, Organometal-

lics 2006, 25, 2914.

[95] M. A. M. Abu-Youssef, R. Dey, Y. Gohar, A. a. A. Massoud,

L. Öhrström, V. Langer, Inorg. Chem. 2007, 46, 5893.

[96] A. Díez, J. Forniés, S. Fuertes, E. Lalinde, C. Larraz, J. A.

López, A. Martín, M. T. Moreno, V. Sicilia, Organometallics

2009, 28, 1705.

[69] M. Munakata, L. P. Wu, G. L. Ning, T. Kuroda-Sowa, M. [97] A. Díez, J. Forniés, C. Larraz, E. Lalinde, J. A. López, A.

Maekawa, Y. Suenaga, N. Maeno, J. Am. Chem. Soc. 1999,

Martín, M. T. Moreno, V. Sicilia, Inorg. Chem. 2010, 49, 3239.

[98] F. M. Hwang, H. Y. Chen, P. S. Chen, C. S. Liu, Y. Chi, C. F.

Shu, F. L. Wu, P. T. Chou, S. M. Peng, G. H. Lee, Inorg. Chem.

2005, 44, 1344.

[99] J. Brooks, Y. Babayan, S. Lamansky, P. I. Djurovich, I. Tsyba,

K. Bau, M. E. Thompson, Inorg. Chem. 2002, 41, 3055.

[100] S. D. Cummings, R. Eisenberg, J. Am. Chem. Soc. 1996, 118,

1949.

121, 4968.

[70] M. Munakata, L. P. Wu, T. Kuroda-Sowa, M. Maekawa, Y.

Suenaga, G. L. Ning, T. Kojima, J. Am. Chem. Soc. 1998, 120,

8610.

[71] M. Munakata, J. C. Zhong, T. Kuroda-Sowa, M. Maekawa, Y.

Suenaga, M. Kasahara, H. Konaka, Inorg. Chem. 2001, 40,

7087.

[72] M. Munakata, L. P. Wu, T. Kuroda-Sowa, M. Maekawa, Y.

Suenaga, T. Ohta, H. Konaka, Inorg. Chem. 2003, 42, 2553.

[73] W.-B. Yuan, R.-D. Yang, L. Tan, Transition Met. Chem. 2004,

29, 380.

[74] F. A. Cotton, L. R. Falvello, R. Usón, J. Forniés, M. Tomás,

J. M. Casas, I. Ara, Inorg. Chem. 1987, 26, 1366.

[75] R. Usón, J. Forniés, M. Tomás, J. M. Casas, F. A. Cotton,

L. R. Falvello, R. Llusar, Organometallics 1988, 7, 2279.

[76] R. Usón, J. Forniés, M. Tomás, J. M. Casas, Angew. Chem.

1989, 101, 782; Angew. Chem. Int. Ed. Engl. 1989, 28, 748.

[77] J. Forniés, R. Navarro, M. Tomás, E. P. Urriolabeitia, Organo-

metallics 1993, 12, 940.

[78] J. M. Casas, L. R. Falvello, J. Forniés, A. Martín, Inorg. Chem.

1996, 35, 7867.

[79] R. Usón, J. Forniés, L. R. Falvello, M. Tomás, J. M. Casas, A.

Martín, Inorg. Chem. 1993, 32, 5212.

[80] A. Martín, A. G. Orpen, J. Am. Chem. Soc. 1996, 118, 1464.

[81] J. C. Zhong, M. Munakata, T. Kuroda-Sowa, M. Maekawa, Y.

Suenaga, H. Konaka, Inorg. Chem. 2001, 40, 3191.

[82] M. Wen, M. Maekawa, M. Munakata, Y. Suenaga, T. Kuroda-

Sowa, Inorg. Chim. Acta 2002, 338, 111.

[83] S. Q. Liu, T. Kuroda-Sowa, H. Konaka, Y. Suenaga, M. Maek-

awa, T. Mizutani, G. L. Ning, M. Munakata, Inorg. Chem.

2005, 44, 1031.

[101] J. A. G. Williams, Chem. Soc. Rev. 2009, 38, 1783.

[102] J. A. G. Williams, Top. Curr. Chem. 2007, 281, 205.

[103] E. J. Maslowsky, Vibrational Spectra of Organometallic Com-

pounds, Wiley, New York, 1977.

[104] CrysAlis, RED Program for X-ray CCD Camera Data Re-

duction, Oxford Diffraction, Oxford, UK, 2004.

[105] G. M. Sheldrick, SHELXL-97, Program for Crystal Structure

Refinement, University of Gottingen, Germany, 1997.

[106] A. D. Becke, J. Chem. Phys. 1993, 98, 5648.

[107] C. T. Lee, W. T. Yang, R. G. Parr, Phys. Rev. B 1988, 37, 785.

[108] Y. Zhao, D. G. Truhlar, Theor. Chem. Acc. 2008, 120, 215.

[109] M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria,

M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B.

Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li,

H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L.

Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J.

Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.

Nakai, T. Vreven, J. A. Montgomery Jr., J. E. Peralta, F. Ogli-

aro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N.

Staroverov, R. Kobayashi, J. Normand, K. Raghavachari, A.

Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N.

Rega, J. M. Millam, M. Klene, J. E. Knox, J. B. Cross, V.

Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Strat-

mann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W.

Ochterski, R. L. Martin, K. Morokuma, V. G. Zakrzewski,

G. A. Voth, P. Salvador, J. J. Dannenberg, S. Dapprich, A. D.

Daniels, Ö. Farkas, J. B. Foresman, J. V. Ortiz, J. Cioslowski,

D. J. Fox, Gaussian 09, Revision A.02, Gaussian, Inc., Wall-

ingford, CT, 2009.

[84] Y.-B. Dong, Y. Geng, J.-P. Ma, R.-Q. Huang, Inorg. Chem.

2005, 44, 1693.

[85] Y.-B. Dong, G.-X. Jin, X. Zhao, B. Tang, R.-Q. Huang, M. D.

Smith, K. E. Stitzer, H.-C. zur Loye, Organometallics 2004, 23,

1604.

[86] Y.-B. Dong, X. Zhao, G.-X. Jin, R.-Q. Huang, M. D. Smith,

Eur. J. Inorg. Chem. 2003, 4017.

[110] D. Andrae, U. Haussermann, M. Dolg, H. Stoll, H. Preuss,

Theor. Chim. Acta 1990, 77, 123.

[111] R. Ditchfield, W. J. Herhe, J. A. Pople, J. Chem. Phys. 1971,

54, 724.

[87] T. Brasey, A. Buryak, R. Scopelliti, K. Severin, Eur. J. Inorg.

Chem. 2004, 964.

[88] M. Munakata, L. P. Wu, G. L. Ning, Coord. Chem. Rev. 2000,

[112] P. C. Hariharan, J. A. Pople, Theor. Chim. Acta 1973, 28, 213.

[113] U. Varetto, MOLEKEL, v. 5.4, Swiss National Supercomput-

ing Centre, Lugano, Switzerland, 2009.

198, 171.

[89] A. P. Côté, G. K. H. Shimizu, Inorg. Chem. 2004, 43, 6663.

[90] X.-M. Lin, Y. Ying, L. Chen, H.-C. Fang, Z.-Y. Zhou, Q.-G.

Zhan, Y.-P. Cai, Inorg. Chem. Commun. 2009, 12, 316.

Received: December 18, 2012

Published Online: ᭿

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Date: 12-02-13 10:38:59

Pages: 18

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FULL PAPER

Pt–Ag Clusters

Trimetallic [{Pt(C₆F₅)(bzq)L}₂Ag]⁺and bi-

metallic [(C₆F₅)(bzq)(PPh₃)PtAg(pyPh₂)]⁺

clusters containing Pt–Ag bonds were pre-

pared from [Pt(C₆F₅)(bzq)L] (bzq = 7,8-

benzoquinolinate). These complexes have

luminescent properties that were studied

and interpreted with the help of time-de-

pendent DFT calculations.

A. Martín,* Ú. Belío, S. Fuertes,

V. Sicilia ......................................... 1–18

Luminescent Pt–Ag Clusters Based on

Neutral Benzoquinolate Cyclometalated

Platinum Complexes

Keywords: Donor–acceptor systems

/

Heterometallic complexes / Cluster com-

pounds / Silver / Platinum / Luminescence /

Metal–metal interactions / Pi interactions /

Density functional calculations

Eur. J. Inorg. Chem. 0000, 0–0

18

Article Doi

Luminescent Pt-Ag clusters based on neutral benzoquinolate cyclometalated platinum complexes

DOI: 10.1002/ejic.201201528

Source and publish data:

Authors:

Article abstract of DOI:10.1002/ejic.201201528

Full text of DOI:10.1002/ejic.201201528

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