Platinum complexes of 5,6-dihydroacenaphtho[5,6-cd]-1,2-dichalcogenoles

Article abstract of DOI:10.1002/ejic.201200967

Six bis(phosphane)platinum complexes bearing dichalcogen acenaphthene ligands have been prepared by metathesis from cis-[PtCl₂(PR ₃)₂] (R₃ = Ph₃, Ph₂Me, PhMe₂) and the dilithium salts of the parent 5,6-dihydroacenaphtho[5, 6-cd]-1,2-dichalcogenoles (AcenapE₂, L1 E = S, L2 E = Se). For their synthesis, the appropriate disulfide or diselenide species was treated with super hydride [LiBEt₃H] to afford the dilithium salt by in situ reduction of the AcenapE₂ E-E bond. Further reaction, by metathetical addition to the cis-platinum precursor afforded the respective platinum(II) complexes [Pt(5,6-AcenapE₂)(PR₃)₂] (R ₃ = Ph₃: E = S 1, Se 2; R₃ = Ph₂Me: E = S 3, Se 4; R₃ = PhMe₂: E = S 5, Se 6). All six complexes have been fully characterised, principally by multinuclear magnetic resonance spectroscopy, IR spectroscopy and MS. The selenium complexes 4 and 6 provide examples of AA′X spin systems, as displayed by their ³¹P{¹H} NMR spectra. The X-ray structures of L1, L2, 1, 2, 5 and 6 were determined and, where appropriate, the platinum metal geometry, peri-atom displacement, splay angle magnitude, acenaphthene ring torsion angles and E···E interactions were analysed. The platinum atoms were found to adopt a distorted square-planar geometry in all four complexes, and the nature of the AcenapE₂ ligand plays little part in the conformation of the substituents bound to the trivalent phosphorus atoms. Six bis(phosphane)platinum complexes bearing 5,6-dihydroacenaphtho[5,6-cd]-1,2- dichalcogenoles (AcenapE₂, E = S, Se) have been prepared. They were formed from the metathetical addition of the dilithium precursors to cis-[PtCl₂(PR₃)₂] (R₃ = Ph ₃, Ph₂Me, PhMe₂). Copyright

Full text of DOI:10.1002/ejic.201200967

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DOI:10.1002/ejic.201200967
Platinum Complexes of 5,6-Dihydroacenaphtho[5,6-cd]-1,2-
dichalcogenoles
Callum G. M. Benson,[a] Catherine M. Schofield,[a]
Rebecca A. M. Randall,[a] Lucy Wakefield,[a] Fergus R. Knight,[a]
Alexandra M. Z. Slawin,[a] and J. Derek Woollins*[a]
Keywords: Platinum complexes / Chalcogens / Metathesis / Acenaphthene
Six bis(phosphane)platinum complexes bearing dichalcogen
acenaphthene ligands have been prepared by metathesis
from cis-[PtCl2(PR3)2] (R3 = Ph3, Ph2Me, PhMe2) and the di-
lithium salts of the parent 5,6-dihydroacenaphtho[5,6-cd]-
1,2-dichalcogenoles (AcenapE2, L1 E = S, L2 E = Se). For
their synthesis, the appropriate disulfide or diselenide spe-
cies was treated with super hydride [LiBEt3H] to afford the
dilithium salt by in situ reduction of the AcenapE2 E–E bond.
Further reaction, by metathetical addition to the cis-platinum
precursor afforded the respective platinum(II) complexes
[Pt(5,6-AcenapE2)(PR3)2] (R3 = Ph3: E = S 1, Se 2; R3 = Ph2Me:
E = S 3, Se 4; R3 = PhMe2: E = S 5, Se 6). All six complexes
have been fully characterised, principally by multinuclear
magnetic resonance spectroscopy, IR spectroscopy and MS.
The selenium complexes 4 and 6 provide examples of AAЈX
spin systems, as displayed by their 31P{1H} NMR spectra. The
X-ray structures of L1, L2, 1, 2, 5 and 6 were determined and,
where appropriate, the platinum metal geometry, peri-atom
displacement, splay angle magnitude, acenaphthene ring
torsion angles and E···E interactions were analysed. The
platinum atoms were found to adopt a distorted square-
planar geometry in all four complexes, and the nature of the
AcenapE2 ligand plays little part in the conformation of the
substituents bound to the trivalent phosphorus atoms.
Transition metal complexes incorporating 1,8-disubsti-
tuted naphthalene ligands have been well documented,[1]
and the majority of examples reported have either bis(phos-
phane) or bis(thiolate) functionalities. Complexes as-
sembled from ligands with Group 16 donor atoms invaria-
bly contain the naphthalene-1,8-dichalcogenole motif,
NapE2.[1] Initial investigations were undertaken by the
group of Teo, who examined the extensive redox chemistry
of tetrathionaphthalene (TTN), tetrachlorotetrathio-
naphthalene (TCTTN) and tetrathiotetracene (TTT) by
preparing a series of singly and doubly bridged platinum
and iridium complexes.[8] Further complexes were prepared
with TTN-type ligands coordinated to Fe, Co and Ni.[9]
Similarly, oxidative addition of [Pd(PPh3)3] and [Pt-
(PPh3)4] to the related hexachloronaphthalene-1,8-dithiole
(hcdtn) ligand affords two mononuclear square-planar
complexes,[10,11] and treatment with RhCl(PPh3)3 results in
the formation of a five-coordinate RhIII complex.[11] In
comparison, the reaction of hcdtn with [Ni(cod)2] and PPh3
affords a memorable trinuclear nickel(II) complex.[10]
Introduction
The coordination chemistry of peri-substituted naphthal-
enes and structurally related systems has been developed
over the last 15 years.[1] Geometric constraints unique to
these frameworks are imposed by a double substitution at
the peri-positions (positions 1 and 8 of the naphthalene
ring, 5 and 6 of acenaphthene),[2,3] which places large he-
teroatoms or groups in close proximity, usually within their
van der Waals radii.[4] A number of investigators have uti-
lised this characteristic of the naphthalene scaffold to study
bonding interactions in main group systems, in which mo-
lecular geometry is determined by competition between at-
tractive (covalent and weak) forces and repulsive interac-
tions (steric strain).[5,6] The distinguishing feature of peri-
substitution is the ability to achieve a relaxed geometry
through the formation of a direct bond between the two
peri-atoms.[7] Furthermore, proximity effects associated
with peri-substitution favour complexation to bridging
metal species, which provide the correct spatial arrange-
ment for bidentate coordination.
During our investigations of peri-substituted naphthal-
enes, we prepared a series of bis(phosphane)platinum com-
plexes bearing dichalcogen-derivatised naphthalene, acen-
aphthene and phenanthrene ligands by oxidative addition
to zero-valent platinum species and from metathetical meth-
ods with cis-[PtCl2(PR3)2].[12] In a comparative study, we
reported a series of binuclear iridium(II) complexes, which
were synthesised from the oxidative reactions of similar di-
[a] EASTChem, School of Chemistry, University of St Andrews,
St Andrews, Fife, KY16 9ST, UK
Fax: +44-1334-463384
E-mail: jdw3@st-and.ac.uk
Homepage: https://risweb.st-andrews.ac.uk/portal/da/persons/j-
derek-woollins%28216cc072-5a91-4408-aadd-
994771a4af27%29.html
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201200967.
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thiole ligands with [{Ir(μ-Cl)(cod)}2].[13] To supplement our E = S, L2 E = Se) have been prepared by metathesis from
initial platinum study, [NapS2Pt(PPh3)2] was further treated cis-[PtCl2(PR3)2] (R3 = Ph3, Ph2Me, PhMe2) and the dilith-
with a range of Pt, Pd, Rh, Ir and Mo complexes to afford ium salts of the parent dichalcogen acenaphthene ligands
a series of bimetallic complexes containing an MMЈS2 (Scheme 1). All six complexes 1–6 and ligands L1 and L2
core.[14] The corresponding reactions with [AuPPh3]ClO4 were synthesised and fully characterised, principally by
and AgClO4 afforded binuclear and tetranuclear gold clus- multinuclear magnetic resonance spectroscopy, IR spec-
ters and tri- or tetranuclear silver clusters; the outcome was troscopy and mass spectrometry. The homogeneity of the
dependent upon the stoichiometry of the reactants.[15] Fur- new compounds was confirmed by microanalysis where
ther examples of multimetallic complexes bearing naphth- possible.
alene dithiolate ligands have been reported in the literature,
which include examples of tetra- and pentanuclear cop- L1)
5,6-Dihydroacenaphtho[5,6-cd]-1,2-dithiole (AcenapS2,
and 5,6-dihydroacenaphtho[5,6-cd]-1,2-diselenole
per(I) complexes of 1,8-naphthalene dithiolate[16] and oligo- (AcenapSe2, L2) were prepared from 5,6-dibromoacenaph-
meric, dimeric and monomeric zinc complexes of 2,7-di- thene by following standard literature procedures.[23,24] The
tert-butylnaphtho[1,8-c,d][1,2]dithiole and naphthoic anhy- synthesis of the platinum metal complexes was based on
dride dithiole.[17] We have also prepared a series of titano- previously well documented routes to complexes of 1,8-di-
cene complexes that incorporate a range of dithioles with substituted naphthalene chalcogenides and related polyaro-
modified naphthalene-1,8-yl backbones by oxidative ad- matic hydrocarbon compounds.[12] For their synthesis, the
dition reactions involving TiCp2(CO)2.[18] A homologous appropriate
series of three Group 4 metallocene complexes was also genole was treated with two equivalents of super hydride
achieved from [MCp*2Cl2] (M = Ti, Zr, Hf).[19]
[LiBEt3H] in tetrahydrofuran at room temperature to gener-
5,6-dihydroacenaphtho[5,6-cd]-1,2-dichalco-
Although the coordination chemistry of sterically ate a reactive dilithium intermediate by in situ reduction
crowded 1,8-disubstituted naphthalenes has been well inves- of the E–E bond. Subsequent metathetical addition to the
tigated, complexes formed from related peri-substituted 1,2- desired cis-platinum precursor afforded the respective plati-
dihydroacenaphthylenes (acenaphthene)[3] have received num(II) complexes [Pt(5,6-AcenapE2)(PR3)2] (R3 = Ph3: E
much less attention. Recently, we have focused on the acen- = S 1, Se 2; R3 = Ph2Me: E = S 3, Se 4; R3 = PhMe2: E =
aphthene skeleton and investigated chalcogen–tin com- S 5, Se 6) in good to moderate yields (43–76%; Scheme 1).
pounds[20] and related halogen–chalcogen and chalcogen–
The 31P{1H} NMR spectroscopic data for the series of
chalcogen derivatives,[21] which were shown to be ideal bis(phosphane) complexes is displayed in Table 1. The spec-
building blocks for the construction of silver(I) coordina- tra of complexes 1, 3 and 5, which bear the sulfur ligand
tion complexes and extended networks.[22] Herein, we de- L1, display the anticipated single resonances with platinum
scribe the preparation and structural analysis of six bis- satellites, which move to lower chemical shifts as the alkyl
(phosphane)platinum complexes [Pt(5,6-AcenapE2)(PR3)2] group attached to the phosphorus atom is varied from R3
1
(R3 = Ph3: E = S 1, Se 2; R3 = Ph2Me: E = S 3, Se 4; R3 = Ph3 to PhMe2 [1 δ = 23.52 ppm, J(31P,195Pt) = 2980 Hz;
1
= PhMe2: E = S 5, Se 6), which were formed by metathetical 3 δ = 4.51 ppm, J(31P,195Pt) = 2926 Hz; 5 δ = –13.14 ppm
methods from 5,6-dihydroacenaphtho[5,6-cd]-1,2-dichalco- 1J(31P,195Pt) = 2861 Hz]. A decrease in the coupling con-
genoles (AcenapE2, L1 E = S, L2 E = Se) and cis- stants of the platinum satellites is also observed from Ph3
[PtCl2(PR3)2] (R3 = Ph3, Ph2Me, PhMe2; Scheme 1).
to PhMe2, which is consistent with the decrease in elec-
tronegativity of the alkyl substituents and an apparent de-
crease in the s character of the bond.[25]
Table 1. 31P{1H} NMR spectroscopic data for 1–6.[a]
1
2
3
4
5
6
δ
23.52
20.19 4.51 1.22 –13.14 –16.22
1J(31P,195Pt) 2980
3020 2926 2958 2861
2861
2J(31P,77Se)
[a] δ in ppm, J in Hz.
–
–
–
–
–
47(cis); 56(trans)
The platinum complexes 2, 4 and 6, which contain two
phosphane ligands and the symmetrical bis-selenium ligand
L2, can be analysed as AAЈX spin systems (disregarding
the satellites for 31P/77Se–195Pt coupling; Figure 1).[26] The
AAЈ nuclei correspond to the two 31P atoms that align with
either a cis or trans configuration with respect to the low
abundance 77Se NMR active isotope, which is the X nucleus
in the spin system (Figure 1). The presence of the NMR-
inactive isotopomer of the X nucleus at the second Se coor-
Scheme 1. Reaction scheme for the preparation of bis(phosphane)
complexes [Pt(5,6-AcenapE2)(PR3)2] 1–6 bearing 5,6-dihydroacen-
aphtho[5,6-cd]-1,2-dichalcogenoles L1 and L2.
Results and Discussion
BisphosphanePlatinum complexes 1–6 bearing 5,6-dihy- dinating site breaks the symmetry of the molecule and en-
droacenaphtho[5,6-cd]-1,2-dichalcogenoles (AcenapE2, L1 sures that the two 31P environments are magnetically in-
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equivalent. This secondary isotopomer effect, combined 47 and 56 Hz, which correspond to the cis and trans cou-
with the presence of weak 31P–31P coupling, creates a com- plings (Figure 1). Although it is impossible to assign the
plex satellite system that is observed in both the 31P and two distinct satellites as being either trans or cis to the 77Se
77Se NMR spectra of these compounds (Figure 1).
nuclei in the system, the J values are consistent with those
found in the naphthalene analogue [Pt(1,8-Se2-nap)-
(PMe3)2] (47 and 53 Hz). In contrast, the 2J(31P,77Se)
cis/trans coupling constants for 2 are of a similar magni-
tude, and thus result in an overlap of the satellites in the
31P NMR spectrum, which make the exact values for the
two couplings difficult to extract. 1J(31PA,31PAЈ) coupling
constants are notoriously small for AAЈX spin systems[27]
and were not observed in the 31P{1H} NMR spectra of 2,
4 and 6. The partial solubility of the complexes also made
it problematic to obtain 77Se NMR spectra with reasonable
signal-to-noise ratios for these complexes.
X-ray Investigations
Figure 1. An expansion of the 31P{1H} NMR spectrum of 6 show-
ing the satellites for cis and trans 2J(31P,77Se) coupling of an AAЈX
spin system [the satellites for the large 1J(31P,195Pt) coupling are
omitted for clarity].
Crystals of L1 and L2 suitable for X-ray diffraction were
obtained by cooling a hot hexane solution to –10 °C over-
night. In addition, single crystals of 1, 2, 5 and 6 were ob-
The expected AAЈX pattern was not fully resolved in the tained by diffusion of hexane into saturated solutions of the
31P{1H} NMR spectrum of 4 because it was difficult to individual compounds in dichloromethane. The selenium li-
obtain data with sufficient signal-to-noise ratios. Neverthe- gand L2 contains two nearly identical molecules in the
less, the standard single resonance (corresponding to mole- asymmetric unit; all other compounds contain one mole-
cules containing NMR-inactive Se nuclei) was observed up- cule in the asymmetric unit. Selected interatomic distances,
field to the signal of the equivalent sulfur complex 3 and angles and torsion angles are listed in Tables 2 and 3. Fur-
1
with the expected satellites for J(31P,195Pt) coupling [4 δ = ther crystallographic information can be found in Table 4
1
1.22 ppm, J(31P,195Pt) = 2958 Hz].
and in the Supporting Information.
In comparison, the 31P{1H} NMR spectra of 2 and 6
5,6-Dihydroacenaphtho[5,6-cd]-1,2-dichalcogenoles
display the expected pattern for the AAЈ nuclei of an AAЈX [AcenapE2, L1 (E = S) and L2 (E = Se), Figure 2) unsur-
spin system.[26] In addition to the established single reso- prisingly adopt similar molecular structures to those of
nances accompanied by platinum satellites [2
δ
=
their naphthalene equivalents NapE2.[29] Nevertheless, the
20.19 ppm, 1J(31P,195Pt) = 3020 Hz; 6 δ = –16.22 ppm, introduction of the ethane linkage at the 1,2-positions in
1J(31P,195Pt) = 2861 Hz], satellites for 77Se coupling are also the acenaphthene molecule naturally reduces the C4–C5–
present in both spectra. In the spectrum of 6, two sets of C6 bond angle (L1/L2 114/113°; cf. NapS2/NapSe2 125/
2
77Se satellites are clearly present with J(31P,77Se) values of 123°)[29] and simultaneously increases the C1–C10–C9
Table 2. Selected interatomic distances [Å] and angles [°] for L1, L2, 1, 2, 5, 6.
L1
SS
L2
SeSe
1
2
5
6
Ligand; peri atoms
L1; SS
L2; SeSe
L1; SS
L2; SeSe
E(1)···E(9)
2.1025(19)
1.498; 58
2.400(2) [2.380(2)]
1.400; 63 [1.420; 63] 0.333; 91
3.267(4)
3.437(3)
0.363; 90
3.273(7)
0.325; 91
3.418(3)
0.381; 90
ΣrvdW–E(1)···E(9);[a] %ΣrvdW
peri-Region bond angles
E(1)–C(1)–C(10)
C(1)–C(10)–C(9)
E(9)–C(9)–C(10)
Sum of bay angles
Splay angle[b]
113.6(3)
120.2(5)
114.4(4)
348.2(7)
–11.8
114.0(9) [117.4(9)]
128.0(11) [122.6(11)] 128.9(8)
114.9(9) [116.3(10)] 127.9(6)
356.9(17) [356.3(17)] 382.5(12)
125.7(7)
127.2(12)
128.0(13)
130.5(10)
385.7(20)
25.7
127.1(11)
128.7(12)
128.0(11)
383.8(20)
23.8
131.0(10)
129.5(11)
125.9(10)
386.4(18)
26.4
–3.1 [-3.7]
22.5
Out-of-plane displacement
E(1)
E(9)
0.022(1)
0.003(1)
–0.053(1) [-0.061(1)]
–0.032(1) [0.023(1)]
0.170(1)
0.075(1)
0.155(1)
0.015(1)
0.044(1)
0.127(1)
0.157(1)
0.014(1)
Central naphthalene ring torsion angles
C:(6)–(5)–(10)–(1)
C:(4)–(5)–(10)–(9)
179.84(1)
179.55(1)
178.96(1) [177.76(1)] 177.98(1)
178.69(1) [177.07(1)] –179.97(1) 178.25(1)
178.51(1)
179.37(1)
178.04(1)
177.36(1)
173.18(1)
[a] Van der Waals radii used for calculations: rvdW(S) 1.80 Å, rvdW(Se) 1.90 Å.[28] [b] Splay angle: Σ of the three bay region angles – 360.
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Table 3. Platinum coordination geometry; selected intramolecular distances [Å] and angles [°] for 1, 2, 5, 6.
Complex
1
2
5
6
Ligand; peri atoms
Metal geometry – bond lengths
E(1)–Pt(1)
E(9)–Pt(1)
P(1)–Pt(1)
L1; SS
L2, SeSe
L1; SS
L2, SeSe
2.336(2)
2.323(3)
2.301(2)
2.295(2)
2.4558(16)
2.4356(16)
2.304(4)
2.324(4)
2.324(5)
2.258(5)
2.267(4)
2.449(3)
2.438(3)
2.279(4)
2.277(5)
P(2)–Pt(1)
2.294(4)
Metal geometry – bond angles
E(1)–Pt(1)–E(9)
E(1)–Pt(1)–P(1)
P(1)–Pt(1)–P(2)
E(9)–Pt(1)–P(2)
E(1)–Pt(1)–P(2)
E(9)–Pt(1)–P(1)
89.07(8)
86.53(8)
97.51(8)
87.54(8)
172.20(9)
172.79(8)
89.27(6)
89.61(15)
84.53(15)
100.84(15)
85.47(14)
173.00(16)
171.87(13)
88.78(6)
86.47(10)
97.68(13)
87.56(10)
170.63(12)
171.95(11)
86.60(11)
100.45(14)
84.67(11)
171.08(10)
173.09(12)
Metal geometry – distortion
E2Pt–P(1) distance
E2Pt–P(2) distance
0.229(1)
–0.281(1)
0.274(1)
–0.351(1)
0.220(1)
–0.196(1)
–0.204(1)
0.240(1)
Envelope geometry
E2C3–Pt angle
E2C3–Pt distance
135.92(1)
1.152(1)
139.16(1)
1.137(1)
134.44(1)
1.175(1)
133.77(1)
1.259(1)
angular splay (L1/L2 120/128°; cf. NapS2/NapSe2 118/ C(10) and C(9) are essentially coplanar, the platinum atom
122°),[29] which consequently elongates the short S–S and in the peri gap is displaced 1.15–1.26 Å above the E2C3
Se–Se peri bonds in these “simple” single-bonded systems plane, and the E(1)–Pt(1)–E(9) plane is inclined by 134–
{L1 2.1025(19) Å, cf. NapS2 2.0879(8) Å; L2 2.400(2) Å 139°.
[2.380(2) Å], cf. NapSe2 2.3639(5) Å}.[29] The steric de-
As a consequence of the ligand geometry, the two phos-
mands imposed by the substitution of heavy chalcogen phane moieties retain a cis orientation around the platinum
atoms are relieved in these systems by the formation of such atom and complete a distorted square-planar geometry. The
strong E–E covalent bonds, regardless of the minor increase P(1)–Pt(1)–P(2) angles for 1 [97.51(8)°] and 2 [97.68(13)°],
in their length. In the sulfur analogue L1, this is ac- which bear the PPh3 moiety, show considerable deviation
companied by a large negative splay angle as the exocyclic from the ideal 90° in accord with previously published ex-
peri bonds naturally converge (–11.8°, cf. NapS2 –11.2°), amples. Counterintuitively, even larger angles are exhibited
and there is only a minor displacement of the sulfur atoms by 5 [100.84(15)°] and 6 [100.45(14)°], despite the incorpo-
from the mean plane of the organic backbone, in line with ration of the less sterically hindered PPhMe2 functionality,
the naphthalene compound (0.01–0.02 Å).[29] Typical for which is associated with a smaller Tolman cone angle
systems incorporating larger substituents, the selenium (PPhMe2 136° cf. PPh3 145°).[30] In contrast, the corre-
counterpart L2 exhibits a more positive splay angle (–3.1° sponding E(1)–Pt(1)–E(9) angles in all four complexes are
[–3.7°], cf. NapSe2 –3.6°),[29] and the two E–CAcenap bonds consistent with angles in the range 88.78(6)–89.61(15)°. The
now adopt a more parallel alignment. Buckling of the two cis E(1)–Pt(1)–P(1), E(9)–Pt(1)–P(2) [84.53(15)–87.56(10)°]
naturally planar carbon frameworks is minimal and com- and trans E(1)–Pt(1)–P(2), E(9)–Pt(1)–P(1) angles
parable to that observed in the naphthalene compounds; [170.63(12)–173.09(12)°] also fall within accepted ranges for
the greatest distortion is observed in the selenium analogue similar platinum complexes[12,27] but highlight the distor-
L2, which has maximum C–C–C–C central acenaphthene tion of the square planar environment at the central plati-
torsion angles in the range 178–179°.
num core. The Pt–S [2.323(3)–2.336(2) Å], Pt–Se [2.436(2)–
Treatment of the dilithium salts of L1 and L2 with cis- 2.456(2) Å] and Pt–P [2.258(5)–2.304(4) Å] bond lengths
[PtCl2(PPh3)2] afforded two isomorphous monomeric, mo- correspond to distances seen in previous naphthalene com-
nonuclear four coordinate platinum(II) complexes [Pt(5,6- plexes.[12,27] In addition to the in-plane deviations, further
AcenapE2)(Ph3)2] (1 E = S; 2 E = Se; Figure 3). Similarly, distortion is observed in all four complexes; out-of-plane
the corresponding reactions with cis-[PtCl2(PPhMe2)2] gen- displacement of the coordinating E and P atoms reduces
erated a pair of equivalent isomorphous platinum(II) com- the planarity of the primary coordination sphere of the
plexes [Pt(5,6-AcenapE2)(PhMe2)2] (5 E = S; 6 E = Se; Fig- platinum atom. This can be compared by monitoring the
ure 4). In each case, the symmetrical bidentate dichalcogen location of the P atoms with respect to the mean E–Pt–
ligand binds through both E atoms to form a chelate ring E plane (Figure 6). In each case E(1), Pt(1) and E(9) are
with the central metal atom. The PtE2C3 six-membered essentially coplanar, and the P atoms are displaced to oppo-
rings are hinged about the E···E vector and adopt a twisted site sides of this plane by 0.2–0.4 Å (Figure 6). The C–E–
envelope-type conformation (Figure 5); E(1), E(9), C(1), Pt bond angles are found to decrease from PPh3 to
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Table 4. Crystallographic data for L1, L2, 1, 2, 5, 6.
L1
L2
1
Empirical formula
Formula weight
Temperature [°C]
Crystal colour, habit
Crystal dimensions [mm3]
Crystal system
C12H8S2
216.32
–148(1)
C12H8Se2
310.12
–148(1)
C48H38P2PtS2
935.99
–180(1)
orange, platelet
0.09ϫ0.09ϫ0.03
monoclinic
a = 13.871(8) Å
b = 4.952(3) Å
c = 14.633(7) Å
β = 116.097(12)°
902.7(8)
P21/n
green, platelet
0.30ϫ0.30ϫ0.02
monoclinic
a = 7.359(5) Å
b = 21.383(14) Å
c = 12.304(9) Å
β = 99.016(19)°
1912(2)
orange, prism
0.20ϫ0.20ϫ0.20
monoclinic
a = 9.769(3) Å
b = 17.571(5) Å
c = 22.605(6) Å
β = 102.379(7)°
3790(2)
Lattice parameters
Volume [Å3]
Space group
P21/n
P21/n
Z
4
8
4
Dcalcd. [gcm–3]
1.592
2.154
1.640
F(000)
448
5.346
1184
76.842
1864
39.177
λ(Mo-Kα) [cm–1]
Number of reflections measured
Rint
7383
0.0660
0.765/0.984
2055(127)
16.18
0.0904
0.1297
0.2913
1.133
15458
0.1143
0.442/0.858
3850(253)
15.22
0.0981
0.1337
0.2569
1.240
23502
0.1206
0.201/0.457
6898(466)
14.80
0.0701
0.0884
0.1938
1.069
Min/max. transmissions
Observed reflection (number of variables)
Reflection/parameter ratio
Residuals: R1 [I Ͼ 2σ(I)]
Residuals: R (all reflections)
Residuals: wR2 (all reflections)
Goodness-of-fit indicator
Maximum peak in final diff. map [eÅ–3]
Minimum peak in final diff. map [eÅ–3]
1.63
–1.01
1.40
–1.85
2.06
–3.40
2
5
6
Empirical formula
Formula Weight
Temperature [°C]
Crystal colour, habit
Crystal dimensions [mm3]
Crystal system
C48H38P2PtSe2
1029.79
–180(1)
orange, prism
0.10ϫ0.10ϫ0.03
monoclinic
a = 9.797(4) Å
b = 17.656(5) Å
c = 22.821(8) Å
–
C28H30P2PtS2
687.70
–148(1)
orange, platelet
0.17ϫ0.08ϫ0.02
triclinic
C28H30P2PtSe2
781.50
–148(1)
orange, plate
0.15ϫ0.15ϫ0.09
triclinic
Lattice parameters
a = 9.978(3) Å
b = 11.416(4) Å
c = 11.731(4) Å
α = 106.918(9)°
β = 92.914(10)°
γ = 95.035(9)°
1269.4(7)
a = 10.111(7) Å
b = 11.637(11) Å
c = 11.678(10) Å
α = 106.30(3)°
β = 94.62(2)°
γ = 93.48(3)°
1310(2)
β = 101.690(8)°
–
3865(3)
Volume [Å3]
Space group
¯
P1
¯
P1
P21/n
Z
4
2
2
Dcalcd. [gcm–3]
1.769
2008
56.169
24021
1.799
676
58.114
8862
0.0909
–
4268(298)
14.32
0.0771
0.0918
0.1529
1.193
1.57
1.982
748
F(000)
λ(Mo-Kα) [cm–1]
82.538
11373
0.0604
0.271/0.476
5707(298)
19.15
0.0611
0.0911
0.2645
1.039
No. of reflections measured
Rint
0.1944
Min./max. transmissions
Observed reflection (number of variables)
Reflection/parameter ratio
Residuals: R1 [I Ͼ 2σ(I)]
Residuals: R (all reflections)
Residuals: wR2 (all reflections)
Goodness-of-fit indicator
Maximum peak in final diff. map [eÅ–3]
Minimum peak in final diff. map [eÅ–3]
0.306/0.845
7007(459)
15.27
0.0898
0.1314
0.2369
1.052
1.83
–2.24
2.28
–4.62
–2.97
PPhMe2; the average angles for 1 and 2 are 111° and 109°
The arrangement of substituents in trivalent phosphorus
for 5 and 6. The reduction in the C–E–Pt angle is consistent ligands is dictated by steric effects; R–P–RЈ angles are com-
with the smaller functionality on the phosphorus atom, monly less than 109.5° and approach an ideal tetrahedral
which allows the platinum atom to lie closer to the ace- geometry as bulky groups are added.[30] In 1, 2, 5 and 6,
naphthene framework.
the nature of the AcenapE2 ligand has no apparent effect
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Figure 6. Out-of-plane distortion of the square-planar geometry in
5 and 6; displacement of the P atoms from the mean E–Pt–E plane
(phenyl and methyl groups and H atoms omitted for clarity).
on the conformation of the phosphorus moiety, and the R–
P–R angles are comparable for 1 (av. 103.5°) and 2 (av.
Figure 2. The molecular structures of 5,6-dihydroacenaphtho[5,6-
cd]-1,2-dichalcogenoles (AcenapE2, L1 E = S, L2 E = Se; H atoms 103.7°), and 5 (av. 102.3°) and 6 (av. 102.8). Although the
omitted for clarity).
average of the CPh–P–CPh angles in 1 and 2 (104°) is closer
to that of a standard tetrahedral arrangement (as expected
for larger substituents),[30] the angles range between 97.6(4)
and an unusually large 111.8(4)° [cf. 5/6 99.6(6)–105.8(8)°].
As might be expected from the larger steric influence of the
PPh3 group compared with that of PPhMe2, longer Pt–P
bonds are observed in 1 and 2 (av. 2.30 Å) than in 5 and 6
(2.27 Å). Although steric effects dominate the configuration
of the substituents around the phosphorus atoms, weak in-
teractions between the functional groups of neighbouring
phosphorus atoms can influence the structure of the com-
plex. In 1 and 2, two neighbouring phenyl rings attached to
independent P atoms adopt a parallel alignment similar to
the face-to-face offset arrangement (Figure 7)[31] and have
nonbonded distances between the interacting centroids
Figure 3. The molecular structures of 1 and 2 formed from cis-
[cg(C25–C30)···cg(C31–C36): 1 3.765(1) Å; 2 3.764(1) Å]
[PtCl2(PPh3)2] and bearing chalcogen ligands L1 and L2 (H atoms
within the range for typical π···π stacking (3.3–3.8 Å).[31]
omitted for clarity).
Similarly, 5 and 6 exhibit weak nonconventional CH···π-
type hydrogen bond interactions[32] between neighbouring
methyl and phenyl moieties of adjacent phosphorus groups
[5 C(14)–H(14C)···cg(C23–C28) 2.61 Å; 6 C(21)–H(21A)···
cg(C15–C20) 2.72 Å; Figure 8].
Figure 4. The molecular structures of 5 and 6 formed from cis-
[PtCl2(PPhMe2)2] (H atoms omitted for clarity).
Figure 7. Overlapping phenyl rings in the isomorphous complexes
1 (shown) and 2 align with a weak face-to-face offset arrangement
and interact through weak π···π stacking.
Unsurprisingly, cleavage of the short E–E covalent bond
and subsequent coordination to the platinum centre in 1, 2,
5 and 6 causes steric strain to accumulate between the bulky
chalcogen atoms. The repulsive interactions between the
two peri functionalities that result from sub-van-der-Waals
Figure 5. The open-envelope configuration of the six-membered
chelate ring formed from bidentate Se coordination of L2 in 6
(phenyl and methyl groups and H atoms omitted for clarity).
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with those of sulfur equivalents 1 and 5, in line with the
greater bulk of the interacting atoms.
During an earlier study of bis(phosphane)platinum com-
plexes bearing a range of dichalcogen derivatised naphth-
alene, acenaphthene and phenanthrene ligands, we prepared
[Pt(1,8-NapSe2)(PPh3)2] N2, which is the naphthalene ana-
logue of 2.[12] Although both compounds adopt comparable
structures in the solid state, the introduction of the ethane
linkage at the 1,2-positions of 2 has a noticeable influence
on the geometry of the phosphorus atom and the degree of
molecular distortion in the organic backbone compared
with those of N2. The greatest discrepancy between the two
compounds is found in the planarity of the organic frame-
works; significantly less buckling is observed within the
acenaphthene ring system of 2 (maximum C–C–C–C cen-
tral ring torsion angles ca. 2°; cf. N2 ca. 1–5°).[12] A re-
duction in out-of-plane distortion is associated with this is;
one of the selenium atoms in 2 essentially resides on the
mean acenaphthene plane, and the second atom is displaced
by only ca. 0.1 Å (cf. N2 both Se atoms displaced ca. 0.2 Å
from the mean naphthalene plane).[12] The natural splay of
the exocyclic bonds in acenaphthene compounds compared
with those of their naphthalene equivalents accounts for the
larger in-plane distortion observed in 2 (splay angle: 25.7°;
cf. N2 23.8° [20.0°]), which results in a minor lengthening
of the Se···Se separation {2 3.437(3) Å; N2 3.37(1) Å
[3.36(1) Å]}.[12]
Although the in-plane Se–Pt–Se (86–89°), Se–Pt–P (86–
89°) and P–Pt–P (98–99°) angles are comparable in both
complexes, the out-of-plane displacement (metal geometry)
of the two P atoms with respect to the Se2Pt plane is mar-
ginally greater in the naphthalene analogue (ca. 0.4–0.5 Å;
cf. 2 0.2–0.3 Å).[12] As might be expected, the PPh3 groups
in 2 adopt a similar configuration to those found in the
Figure 8. Adjacent phenyl and methyl moieties interact in 5 (top)
and 6 (bottom) through weak nonconventional CH···π-type inter-
actions.
contacts lead to deformation of the carbon framework by naphthalene analogue, and both complexes have compar-
in-plane and out-of-plane distortions and buckling of the able R–P–R angles (98–113°). Interestingly, although the
aromatic ring system (angular strain), which ultimately dis- neighbouring phenyl rings of complex N2 overlap, the dis-
rupts the relaxed geometry previously achieved by the free tance between the two interacting centroids {4.167(1) Å
ligands. As a consequence of the square planar metal geom- [4.166(1) Å]} is outside the range for standard π···π stacking
etry, the exocyclic E–CAcenap bonds now diverge, which re- (3.3–3.8 Å).[12,31]
sults in large positive splay angles in the range 23–26° and
extended nonbonded E···E distances more than 1 Å longer
than the E–E distances in the AcenapE2 ligands [1 3.267(4),
5 3.273(7); cf. L1 2.1025(19); 2 3.437(3), 6 3.418(3); cf. L2
Conclusions
2.400(2) Å]. This is accompanied by an increase in the out-
The work presented in this paper builds on our previous
of-plane displacement of the peri atoms (0–0.2; cf. L1/L2 studies of bis(phosphane)platinum complexes bearing di-
0–0.05 Å) and a reduction in the planarity of the carbon chalcogenide based ligands.[12] Herein, we present the syn-
skeleton (C–C–C–C torsion angles 0.1–7°; cf. L1/L2 0– thesis of a related series of platinum complexes 1–6 that
0.1°). As can be seen from the magnitude of the E···E peri incorporate
5,6-dihydroacenaphtho[5,6-cd]-1,2-dichalco-
separations, the subtle change of the phosphorus function- genoles [AcenapE2, L1 (E = S), L2 (E = Se)] and cis-
ality from PPh3 to PPhMe2 has only a minor effect on the [PtCl2(PR3)2] (R3 = Ph3, Ph2Me, PhMe2). For their synthe-
geometry of the acenaphthene fragment in these complexes. sis, the appropriate disulfide or diselenide species was
The most notable difference is observed within the bay re- treated with super hydride [LiBEt3H] to afford the dilithium
gion, and marginally larger splay angles are exhibited by 2 salt by in situ reduction of the AcenapE2 E–E bond. Fur-
and 6 (PPhMe2), which are ca. 1° larger than those of 1 ther reaction by metathetical addition to the cis-platinum
and 5 (PPh3). Naturally, the selenium analogues 2 and 6 precursor afforded the respective platinum(II) complex
exhibit greater molecular distortion within the acenaph- [Pt(5,6-AcenapE2)(PR3)2] (R3 = Ph3: E = S 1, Se 2; R3 =
thene fragment and longer peri E···E distances compared Ph2Me: E = S 3, Se 4; R3 = PhMe2: E = S 5, Se 6). The
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spectrometer with δ(H) and δ(C) referenced to external tetramethyl-
silane. 31P and 77Se NMR spectra were recorded with a Jeol GSX
270 MHz spectrometer with δ(P) and δ(Se) referenced to external
phosphoric acid and dimethylselenide, respectively. Assignments of
13C and 1H NMR spectra were made with the help of H–H COSY
and heteronuclear single quantum coherence (HSQC) experiments.
All measurements were performed at 25 °C. All values reported
for NMR spectroscopy are in parts per million (ppm). Coupling
constants (J) are given in Hertz [Hz]. Mass spectrometry was per-
formed by the University of St. Andrews Mass Spectrometry Ser-
sulfur complexes 1, 3 and 5 display the expected single reso-
nances with platinum satellites in their 31P{1H} NMR spec-
tra, which move to lower chemical shifts with decreasing
1J(31P,195Pt) coupling constants as the alkyl group on the
phosphorus atom is varied from R3 = Ph3 to PhMe2. The
inclusion of the low abundance 77Se NMR active isotope in
complexes 2, 4 and 6 provides extra complexity to their
31P{1H} NMR spectra. These can be analysed as AAЈX
systems if the satellites for 31P/77Se–195Pt coupling are disre-
garded.[26] The AAЈ nuclei correspond to the two 31P atoms vice; Electrospray mass spectrometry (ESMS) was carried out with
a Micromass LCT orthogonal accelerator time of flight mass spec-
trometer. Platinum metal precursors cis-[PtCl2(PR3)] (R3 = Ph3,
Ph2Me, PhMe2) were prepared following standard literature pro-
cedures.[12]
that align with either a cis or trans configuration with re-
spect to the X nucleus in the spin system (the 77Se NMR
active isotope), which makes them magnetically inequiva-
lent. The 31P{1H} NMR spectra of 6 displays the expected
pattern for the AAЈ nuclei of an AAЈX spin system;[26] in
addition to the established single resonance accompanied
by satellites for 1J(31P,195Pt) coupling, two sets of 77Se satel-
5,6-Dihydroacenaphtho[5,6-cd][1,2]dithiole [AcenapS2] (L1): The
title compound was prepared by a method previously described.[23]
To
a
stirred solution of 5,6-dibromoacenaphthene (5.0 g,
16.03 mmol) and tetramethylethylenediamine (TMEDA, 4.8 mL,
16.03 mmol) in diethyl ether (200 mL) was slowly added a hexane
solution of n-butyllithium (2.5 m, 6.4 mL, 16.03 mmol) at –78 °C.
After the mixture was stirred for 15 min at this temperature, sulfur
flowers (0.51 g, 16.03 mmol) were added and stirring was continued
at –40 °C for 2 h. The mixture was cooled again to –78 °C, after
2
lites are clearly present and have J(31P,77Se) values of 47
and 56 Hz for the cis and trans couplings. 1J(31PA,31PAЈ)
coupling constants are notoriously small for AAЈX spin
systems and were not observed in the spectra of 2, 4 and
6.[27]
The X-ray structures were determined for 1, 2, 5 and 6,
which
a hexane solution of n-butyllithium (2.5 m, 6.4 mL,
and the platinum metal geometry, peri-atom displacement, 16.03 mmol) was added and the reaction mixture was stirred at this
temperature for 15 min. Additional sulfur (0.51 g, 16.03 mmol) was
added and the reaction mixture was stirred for a further 2 h at
–40 °C. The mixture was then quenched with acetic acid (2 mL)
and exposed to an air stream overnight for oxidation. The resulting
solution was concentrated under reduced pressure and after water
was added, the mixture was extracted with dichloromethane. The
extract was dried with anhydrous magnesium sulfate. After the sol-
vent was removed in vacuo, the residue was purified by column
chromatography on silica gel (hexane). An analytically pure sample
was obtained by recrystallisation from hexane to give the desired
splay angle magnitude, acenaphthene ring torsion angles
and E···E interactions were analysed and compared to those
of the free ligands L1 and L2. In each complex, the sym-
metrical bidentate AcenapE2 ligand coordinates to the
platinum atom to form a six-membered chelate ring that
adopts a twisted envelope-type motif. The two phosphane
ligands retain a cis orientation around the platinum atom,
which is at the centre of a distorted square-planar environ-
ment. Naturally, the coordination to platinum and cleavage
of the E–E bond results in a dramatic increase in molecular product as orange crystals (0.70 g, 20%); m.p. 178–182 °C. C12H8S2
(216.32): calcd. C 66.6, H 3.7; found C 66.5, H 3.8. 1H NMR
distortion in the acenaphthene component of 1, 2, 5 and 6
compared with those of the free ligands L1 and L2. Diver-
gence of the exocyclic bonds results in large positive splay
(270 MHz, CDCl3, 25 °C, Me4Si): δ = 7.06 (d, 3JHH = 7.5 Hz, 1 H,
acenaph. 4,7-H), 7.02 (d, 3JHH = 7.2 Hz, 1 H, acenaph. 3,8-H), 3.29
(s, 4 H, 2ϫ CH2) ppm. 13C NMR (67.9 MHz, CDCl3, 25 °C,
angles in the range 23–26° and extended nonbonded E···E
Me4Si): δ = 121.1 (s), 116.9 (s), 30.7 (s,CH2) ppm. (ES+): m/z 215.87
distances that are 1 Å longer than the E–E distances in the
([M]+, 100%).
AcenapE2 ligands. The nature of the AcenapE2 ligand has
no apparent effect on the conformation of the phosphorus
moiety, and 1 and 2, and 5 and 6 have comparable R–P–
R angles. Similarly, the subtle change of the phosphorus
functionality from PPh3 to PPhMe2 has only a minor effect
on the geometry of the acenaphthene fragment in these
complexes.
5,6-Dihydroacenaphtho[5,6-cd][1,2]diselenole [AcenapSe2] (L2): The
title compound was prepared by a method previously described.[23]
To
a stirred solution of 5,6-dibromoacenaphthene (2.62 g,
8.40 mmol) and TMEDA (2.5 mL, 16.1 mmol) in diethyl ether
(200 mL) was slowly added a 2.5 m hexane solution of n-butyllith-
ium (3.4 mL, 8.40 mmol) at –78 °C. After the mixture was stirred
for 15 min at this temperature, selenium powder (0.66 g,
8.40 mmol) was added and stirring was continued at –40 °C for 2 h.
The mixture was cooled again to –78 °C, after which a 2.5 m hexane
solution of n-butyllithium (3.4 mL, 8.40 mmol) was added and the
reaction mixture stirred at this temperature for 15 min. Additional
selenium powder (0.66 g, 8.40 mmol) was added and the reaction
mixture stirred for a further 2 h at –40 °C. The mixture was then
quenched with acetic acid (2 mL) and exposed to an air stream
overnight for oxidation. The resulting solution was concentrated
under reduced pressure and after water was added, the mixture
was extracted with dichloromethane. The extract was dried with
anhydrous magnesium sulfate. After the solvent was removed in
vacuo, the residue was purified by column chromatography on sil-
ica gel (hexane/dichloromethane). An analytically pure sample was
Experimental Section
General: All experiments were carried out under an oxygen- and
moisture-free nitrogen atmosphere using standard Schlenk tech-
niques and glassware. Reagents were obtained from commercial
sources and used as received. Dry solvents were collected from an
MBraun solvent system. Elemental analyses were performed by
Stephen Boyer at the London Metropolitan University. Infrared
spectra were recorded as KBr discs in the range 4000–300 cm–1 with
a Perkin–Elmer System 2000 Fourier transform spectrometer. 1H
and 13C NMR spectra were recorded with a Jeol GSX 270 MHz
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2
obtained by recrystallization from boiling toluene to give the de-
sired product as green crystals (0.83 g, 32%); m.p. 198–200 °C.
C12H8Se2 (310.12): calcd. C 46.5, H 2.6; found C 46.5, H 2.6. H
= 7.3 Hz, 4 H, PPh 14-H), 6.85 (d, JH,H = 7.2 Hz, 2 H, acenaph.
3,8-H), 3.06 (s, 4 H, acenaph. CH2), 1.84–1.70 (m, 6 H, PCH3)
ppm. 13C NMR (67.9 MHz. CDCl3; 25 °C; Me4Si): δ = 141.9 (s),
132.8 (t, J = 5.5 Hz, Ph-2), 131.4 (s), 130.4 (s), 128.3 (t, J = 5.2 Hz),
120.4 (s), 119.5 (s), 30.3 (s), 15–14.4 (m, CH3) ppm. 31P NMR
(109 MHz, CDCl3, 25 °C, H3PO4): δ = 4.51 (JP,Pt = 2926 Hz) ppm.
MS (ESI+): m/z (%) = 703.69 (100) [M – SPh]+.
1
3
NMR (270 MHz, CDCl3, 25 °C, Me4Si): δ = 7.21 (d, JH,H
=
3
7.4 Hz, 1 H, acenaph. 4,7-H), 7.05 (d, JH,H = 7.2 Hz, 1 H, acen-
aph. 3,8-H), 3.26 (s, 4 H, 2ϫ CH2) ppm. 13C NMR (67.9 MHz,
CDCl3, 25 °C, Me4Si): δ = 121.7 (s), 121.2(s), 30.4 (s, acenaph.
CH2) ppm. 77Se NMR (51.5 MHz, CDCl3, 25 °C, Me2Se): δ = 424
(s) ppm. MS(ESI+): m/z (%) = 311.90 (100) [M + H]+, 309.91 (70)
[M]+.
[Pt(PPh2Me)2L2] (4): Compound 4 was prepared by following a
similar procedure to that described for 1 but with super hydride
(1.1 mL, 1.1 mmol), L2 (0.18 g, 0.56 mmol) and cis-
[PtCl2(PPh2Me)2] (0.38 g, 0.56 mmol). The resulting microcrystal-
line solid was collected by filtration and washed with diethyl ether
to yield the product as an orange powder (0.2 g, 43%); m.p. 184–
185 °C. C38H34P2PtSe2 (905.64): calcd. C 50.3, H 3.8; found C 50.3,
H 3.7. 1H NMR (400 MHz, CDCl3, 25 °C, Me4Si): δ = 7.82 (d,
3JH,H = 7.3 Hz, 2 H, acenaph. 4,7-H), 7.55–7.45 (m, 9 H, PPh 14-
H), 7.45–7.35 (m, 4 H, PPh 12,16-H), 7.33–7.27 (m, 8 H, PPh
[Pt(PPh3)2L1] (1): Super hydride (1.1 mL of a 1.0 m solution in
THF, 1.1 mmol) was added in one portion to a solution of 5,6-
dihydroacenaptho[5,6-cd][1,2]dithiole (acenaph.S2) L1 (0.12 g,
0.56 mmol) in THF (20 mL). A colour change from bright red to
pale yellow was observed, along with a small evolution of gas. The
solution was transferred with a syringe to a suspension of cis-
[PtCl2(PPh3)2] (0.45 g, 0.56 mmol) in THF (10 mL) and stirred for
2 d to give a yellow solution. The mixture was filtered through a
silica pad and eluted with dichloromethane (100 mL). The filtrate
was evaporated to dryness under reduced pressure and redissolved
in a minimum amount of dichloromethane (ca. 10 mL). Diethyl
ether (25 mL) and hexane (50 mL) were added slowly to induce
precipitation. The resulting microcrystalline solid was collected by
filtration and was washed with diethyl ether to yield the product as
a light orange powder (0.4 g, 74%); m.p. 282–284 °C. C48H38P2PtS2
(935.99): calcd. C 61.6, H 4.1; found C 61.4, H 4.0. 1H NMR
(400 MHz, CDCl3, 25 °C, Me4Si): δ = 7.48–7.38 (m, 12 H, PPh
3
13,18-H), 6.92 (d, JH,H = 7.2 Hz, 2 H, acenaph. 3,8-H), 3.18 (s, 4
H, acenaph. CH2), 1.91 (s, 6 H, PCH3) ppm. 13C NMR (67.9 MHz,
CDCl3, 25 °C; Me4Si): δ = 143.4 (s), 133.00–132.6 (m), 130.4 (s),
128.2 (t, J = 5.1 Hz), 119.3 (s), 30.1 (s), 14.9–14.7 (m, CH3) ppm.
31P NMR (162 MHz, CDCl3, 25 °C, H3PO4): δ = 1.22 (JPPt
2958 Hz) ppm. MS(ESI+) m/z (%) = 929.07 (35) [M + Na]+.
=
[Pt(PPhMe2)2L1] (5): Compound 5 was prepared by following a
similar procedure to that described for 1 but with super hydride
(1.1 mL, 1.1 mmol), L1 (0.12 g, 0.56 mmol) and cis-
[PtCl2(PPhMe2)] (0.31 g, 0.56 mmol). The resulting microcrystal-
line solid was collected by filtration and washed with diethyl ether
to yield the product as a yellow solid (0.2 g, 50%); m.p. 265–270 °C.
C28H30P2PtS2 (687.70): calcd. C 48.9, H 4.4; found C 48.8, H 4.3.
3
12,16-H), 7.34–7.26 (m, 6 H, PPh 14-H), 7.27 (d, JH,H = 7.3 Hz,
3
4
2 H, acenaph. 4,7-H), 7.14 (td, JH,H = 7.7, JH,H = 1.8 Hz, 12 H,
3
PPh 13,18-H), 6.90 (d, JH,H = 7.3 Hz, 2 H, acenaph. 3,8-H), 3.17
(s, 4 H, acenaph.-CH2) ppm. 13C NMR (75 MHz, CDCl3, 25 °C,
Me4Si): δ = 142.0 (s), 140.7 (s), 135.4–134.8 (m), 130.4 (s), 128.6–
127.4 (m), 119.7 (s), 30.9 (s,CH2) ppm. 31P NMR (109 MHz,
CDCl3, 25 °C, H3PO4): δ = 23.5 (JP,Pt = 2980 Hz) ppm. MS(ESI+):
m/z (%) = 826.66 (100) [M – SPh]+.
IR (KBr disk): ν
= 3442 (s), 3002 (w), 2908 (w), 2830 (w), 1627
˜
max
(w), 1550 (w), 1479 (w), 1429 (s), 1402 (s), 1323 (w), 1293 (w), 1228
(w), 1178 (w), 1104 (w), 1033 (w), 947 (s), 906 (vs), 835 (w), 737
(w), 714 (w), 690 (w), 619 (w), 524 (w), 495 (w), 436 (w) cm–1. H
1
3
NMR (400 MHz, CDCl3, 25 °C, Me4Si): δ = 7.78 (d, JH,H
=
[Pt(PPh3)2L2] (2): Complex 2 was prepared following a similar pro-
cedure described for 1 but with super hydride (1.1 mL, 1.1 mmol),
7.3 Hz, 2 H, acenaph. 4,7-H), 7.49–7.25 (m, 8 H, PPh 12,16-H),
7.28 (d, J = 4.4 Hz, 2 H, PPh 13,18-H), 6.99 (d, JH,H = 7.2 Hz,
2
3
L2 (0.18 g, 0.56 mmol) and cis-[PtCl2(PPh3)2] (0.45 g, 0.56 mmol). 2 H, acenaph. 3,8-H), 3.19 (s, 4 H, acenaph. CH2), 1.80–1.65 (m,
The resulting solid was removed by filtration, washed with toluene
(5 mL) and diethyl ether (2ϫ10 mL) and dried in vacuo to yield
an orange powder (0.3 g, 54%); m.p. 185–186 °C. C48H38P2PtSe2
(1029.79): calcd. C 56.0, H 3.7; found C 55.9, H 3.8. 1H NMR
6 H, PCH3) ppm. 13C NMR (67.9 MHz, CDCl3, 25 °C, Me4Si): δ
= 141.7 (s), 140.7 (s), 132.4 (s), 132.2 (s), 130.9 (t, J = 5.2 Hz),
130.3 (s), 128.5 (t, J = 5.1 Hz), 127.7 (t, J = 6.7 Hz), 119.4 (s), 30.5
(s), 13.9–13.0 (m, CH3) ppm. 31P NMR (109 MHz, CDCl3, 25 °C,
H3PO4): δ = –13.14 (JP,Pt = 2861, JP,P 8.4 Hz) ppm. MS(ESI+): m/z
(%) = 578.70 [M – SPh]+.
3
(400 MHz, CDCl3, 25 °C, Me4Si): δ = 7.51 (d, JH,H = 7.28 Hz, 2
H, acenaph. 4,7-H), 7.48–7.39 (m, 12 H, PPh 12,16-H), 7.35–7.26
(m, 6 H, PPh 14-H), 7.10 (t, 3JH,H = 7.06 Hz, 12 H, PPh 13,18-H),
[Pt(PPhMe2)2L2] (6): Compound 6 was prepared by following a
similar procedure to that described for 1 but with super hydride
(1.1 mL, 1.1 mmol), L2 (0.18 g, 0.56 mmol) and cis-
[PtCl2(PPhMe2)] (0.31 g, 0.56 mmol). The resulting microcrystal-
line solid was collected by filtration and washed with diethyl ether
3
6.81 (d, JH,H = 7.25 Hz, 2 H, acenaph. 3,8-H), 3.13 (s, 4 H, 2ϫ
CH2) ppm. 13C NMR (67.9 MHz. CDCl3; 25 °C; Me4Si): δ = 143.2
(s), 143.7 (t, J = 5.4 Hz), 130.0 (s), 128.0 (t, J = 5.2 Hz), 119.3 (s),
30.1 (s, CH2) ppm. 31P NMR (109 MHz, CDCl3, 25 °C, H3PO4): δ
= 20.2 (JP,Pt = 3020 Hz) ppm. 77Se NMR (52 MHz, CDCl3, 25 °C,
PhSeSePh): δ = 167.3 (pt) ppm.[33] MS(ESI+): m/z (%) = 874.00
(100) [M – SePh]+.
to yield
a
yellow solid (0.2 g, 45%); m.p. 184–185 °C.
C28H30P2PtSe2 (781.50): calcd. C 43.0, H 3.9; found C 42.8, H 3.2.
3
1H NMR (400 MHz, CDCl3, 25 °C, Me4Si): δ = 7.88 (d, JH,H
=
[Pt(PPh2Me)2L1] (3): Compound 3 was prepared following a sim-
ilar procedure as that described for 1 but with super hydride
7.2 Hz, 2 H, acenaph. 4,7-H), 7.45–7.35 (m, 4 H, PPh 12,16-H),
7.30–7.26 (m, 4 H, PPh 13,18-H), 7.20 (m, 2 H, 4-H), 6.85 (d, 3JH,H
(1.1 mL, 1.1 mmol), L1 (0.12 g, 0.56 mmol) and cis- = 7.3 Hz, 2 H, acenaph. 3,8-H), 3.09 (s, 4 H, CH2), 1.80–1.60 (m,
[PtCl2(PPh2Me)2] (0.375 g, 0.564 mmol). The resulting microcrys-
talline solid was collected by filtration and washed with diethyl
ether to yield the product as a bright orange powder (0.3 g, 65%);
12 H, PCH3) ppm. 13C NMR (67.9 MHz, CDCl3, 25 °C, Me4Si): δ
= 141.7 (s), 140.7 (s), 132.4 (s), 132.2 (s), 130.8 (t, J = 5.2 Hz),
130.3 (s), 128.5 (t, J = 5.1 Hz) 127.6 (t, J = 6.7 Hz), 119.4 (s), 30.5
m.p. 275–278 °C. C38H34P2PtS2 (811.84): calcd. C 56.2, H 4.2; (s), 13.8–13.7 (m, CH3) ppm. 31P NMR (109 MHz, CDCl3, 25 °C,
1
found C 55.9, H 3.8. H NMR (400 MHz, CDCl3, 25 °C, Me4Si): H3PO4): δ = –16.22 (JP,Pt = 2895, J
67, JP Ј,Se 40, JP,P 12.4 Hz)
PA,Se
A
2
δ = 7.46 (d, JH,H = 7.3 Hz, 2 H, acenaph. 4,7-H), 7.42–7.32 (m, 8
ppm. 77Se NMR (52 MHz, CDCl3, 25 °C, PhSeSePh): δ = 426.2
(pt) ppm.[33] MS(ESI+): m/z (%) = 625.99 (100) [M – SePh]+.
2
H, PPh 12,16-H), 7.32–7.24 (m, 8 H, PPh 13,18-H), 7.17 (d, JH,H
Eur. J. Inorg. Chem. 2013, 427–437
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© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
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Received: August 22, 2012
Published Online: November 26, 2012
Eur. J. Inorg. Chem. 2013, 427–437
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© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim