Versatile Coordination Modes of Triphospha-1,4-pentadiene-2,4-diamine

Article abstract of DOI:10.1021/acs.inorgchem.8b00067

1,3,5-Triphospha-1,4-pentadiene-2,4-diamine reacts with [M(CO)₄L] (M = Mo, L = nbd (norbornadiene); M = W, L = 2 CH₃CN) to give the chelate complexes [M(CO)₄(PMes{C(NHCy)PMes}₂-κP¹,P³)]. In

Full text of DOI:10.1021/acs.inorgchem.8b00067

Article
pubs.acs.org/IC
Cite This: Inorg. Chem. XXXX, XXX, XXX−XXX
Versatile Coordination Modes of Triphospha-1,4-pentadiene-2,4-
diamine
Anup K. Adhikari, Toni Grell, Peter Lonnecke, and Evamarie Hey-Hawkins*
̈
Faculty of Chemistry and Mineralogy, Institute of Inorganic Chemistry, Johannisallee 29, D-04103 Leipzig, Germany
S
* Supporting Information
ABSTRACT: 1,3,5-Triphospha-1,4-pentadiene-2,4-diamine
reacts with [M(CO)4L] (M = Mo, L = nbd (norbornadiene);
M = W, L = 2 CH3CN) to give the chelate complexes
[M(CO)4(PMes{C(NHCy)PMes}2-κP1,P3)]. In contrast, an
unusual intramolecular rearrangement occurred with [Cu-
(CH3CN)4]PF6 leading to the dimeric copper(I) complex
[Cu(CNCy){PHMesPMesC(NHCy)PMes-κP1,P3}]2(PF6)2.
The mechanism of the rearrangement was supported by
quantum-mechanical calculations. The transition-metal com-
plexes were characterized by multinuclear NMR spectroscopy,
mass spectrometry, infrared spectroscopy, and X-ray crystal-
lography.
INTRODUCTION
RESULTS AND DISCUSSION
■
■
Ligands containing soft1 phosphorus and hard nitrogen donor
atoms have been investigated intensively over the past decades.2
Among the variety of P,N ligand systems, pincer ligands and
their metal complexes have received interest due to their high
stability, versatility, and activity.3 The introduction of a PC
functionality in a pincer ligand enhances the reactivity
remarkably.4 The chemistry of low-coordinate phosphorus
compounds, such as phosphinidenes and phosphaalkenes, is an
active research area,5 as compounds with PC double bonds
possess low-lying π* orbitals, which can act as effective π
acceptors in the coordination of transition metals.5g,6 The η1
coordination mode of phosphaalkenes toward metal atoms or
ions is common, but the η2 coordination mode of
phosphaalkenes is also known (Figure 1).5v,6 Chelating
The reaction of 1,3,5-triphospha-1,4-pentadiene-2,4-diamine
(1) with 1 equiv of [M(CO)4L] (M = Mo, L = nbd; M = W, L
= 2 CH3CN) gave the corresponding molybdenum(0) and
tungsten(0) complexes [M(CO)4(PMes{C(NHCy)PMes}2-
κP1,P3)] (M = Mo (2), M = W (3)), in which 1 coordinates
via the two terminal phosphorus atoms in a cis arrangement
resulting in a six-membered ring (Scheme 1).
Scheme 1. Synthesis of Mo Complex 2 and W Complex 3
Complexes 2 and 3 were isolated as air- and moisture-stable
crystalline orange (2) or dark red (3) solids suitable for single-
crystal X-ray diffraction studies. In both complexes the metal
center has an almost perfect octahedral coordination sphere
(Figure 2 for 2; Supporting Information for 3). The
coordination of the phosphorus atoms is in accordance with
the hard-soft acid-base (HSAB) principle, as both the
phosphorus atom and the group 6 metal atoms are soft;1 the
six-membered rings have a boat conformation (Figure 3). The
P−C bond lengths of the central P2 atom from 1.852(2) to
1.872(2) Å correspond to single bonds.5k,8 In contrast, the
Figure 1. Different bonding modes of phosphaalkenes in metal
complexes.
phosphaalkene complexes have also been described.7 Recently,
we reported the synthesis of 1,3,5-triphospha-1,4-pentadiene-
2,4-diamine (1) with a PC(N)−P−C(N)P arrangement,
which contains P, N, and PC double bonds as potential
donors.8
Here, we report the coordination behavior of 1 toward
molybdenum(0), tungsten(0), and copper(I).
Received: January 10, 2018
© XXXX American Chemical Society
A
DOI: 10.1021/acs.inorgchem.8b00067
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shorter than a carbon−nitrogen single bond.9 Both observa-
tions indicate a conjugation of the lone pair of electrons on the
nitrogen atoms with the terminal PC bonds. The M−P bond
lengths in 2 and 3 are comparable with other reported
phosphaalkene complexes, such as cis-[Mo(CO)4(1-PPh2-2-
CHPMes*-C6H4-κP,P′)] (Mes* = 2,4,6-tBu3C6H2), cis-
[W(CO)4(PhPCPh2-κP)2], [W(CO)5(RPCHCHMe2-
κP)] (R = Ph, tBu, Men (Men = menthyl)), [W(CO)5(RP
C(2-C6H4OMe)OEt-κP)] (R = CH(NMe2)2, tBu), [W(CO)5-
(Me3SiPC(2-C6H4Me)OEt-κP)].10,11 In comparison, the
M−P bonds in (diphosphazane)molybdenum(0) tetracarbonyl
complexes12 are shorter and in (diphosphinidenecyclobutene)-
molybdenum(0) tetracarbonyl complexes13 longer than ob-
served for 2 and 3.
The M−CO bonds trans to the phosphorus atoms of the
bidentate ligand 1 are shorter (∼1.98 Å) than the other two
M−CO bonds (∼2.04 Å), which is due to the weaker π-acid
character of the phosphaalkene group compared to the
carbonyl group.
Figure 2. Molecular structure of 2. Thermal ellipsoids are set at 50%
probability (H atoms other than N−H and disordered diethyl ether
molecule are omitted for clarity). Selected bond lengths [Å] and bond
angles [deg] of 2 (values of 3 (molecular structure not shown) in []):
P2−C1 1.872(2) [1.872(2)], P2−C2 1.858(2) [1.852(2)], P1−C1
1.709(2) [1.712(2)], P3−C2 1.715(2) [1.714(2)], C1−N1 1.358(2)
[1.352(2)], C2−N2 1.353(2) [1.356(2)], P1−M1 2.5121(5)
[2.5117(4)], P3−M1 2.5116(5) [2.4921(4)], M1−C43 1.987(2)
[1.975(2)], M1−C44 1.972(2) [1.985(2)], M1−C42 2.032(2)
[2.028(2)], M1−C45 2.041(2) [2.037(2)], C42−O1 1.144(3)
[1.148(2)], C43−O2 1.148(3) [1.155(2)], C44−O3 1.155(3)
[1.155(2)], C42−O4 1.145(3) [1.146(2)], N1−C1−P2 111.8(1)
[109.9(1)], N2−C2−P2 115.0(1) [114.4(2)], N1−C1−P1 132.2(1)
[132.5(1)], N2−C2−P3 130.5(1) [130.0(1)], P2−C1−P1 115.47(9)
[117.20(8)], P2−C2−P3 113.59(9) [114.47(8)], C2−P2−C1
109.29(8) [110.65(7)], C1−P1−M1 121.74(6) [119.86(5)], C2−
P3−M1 121.61(6) [122.37(5)], P3−M1−P1 86.37(2) [86.47(1)],
M1−C42−O1 178.1(2) [177.3(2)], M1−C43−O2 178.5(2)
[177.5(2)], M1−C44−O3 178.8(2) [177.4(2)], M1−C45−O4
176.5(2) [178.3(2)].
The 31P{1H} NMR spectra display a triplet (14.2 ppm for 2,
17.5 ppm for 3) for the central phosphorus atom (P2) (−10.9
ppm in 1)8 and a doublet (80.5 ppm for 2, 55.8 ppm for 3) for
the terminal phosphorus atoms (A2B spin system) (97.0 and
102.4 ppm in 1).8 A similar effect was also observed in inversely
polarized phosphaalkenes reported by L. Weber and co-
workers.11f The JPP coupling constants in 2 and 3 (142 and
2
141 Hz, respectively) are larger than those in the free ligand 1
(2JPP 9 and 59 Hz).8 For complex 3, satellites due to coupling to
183W (I = 1/2; natural abundance: 14.31%) are observed for the
1
doublet. The JPW coupling constant is 236 Hz, also suggesting
a cis coordination of the ligand to the W(CO)4 fragment.14 For
local C2v symmetry, four absorptions would be expected in the
infrared spectra of complexes 2 and 3; only three intense
ν(CO) bands in the region of 1860−2013 cm−1 are observed
indicating some overlap of absorptions.15
When [Cu(CH3CN)4]PF6 was reacted with 1, the unusual
dimeric copper(I) complex 4 was obtained (Scheme 2). In this
reaction, a new P−P bond is created between the two
neighboring phosphorus atoms of the starting material 1. As
1,3,5-triphospha-1,4-pentadiene-2,4-diamine (1) is obtained as
one of three products by insertion of cyclohexyl isonitrile into
the P−P bonds of [P4Mes4]2−,8 the reaction observed here
between 1 and [Cu(CH3CN)4]PF6 can be regarded as a part-
way reverse reaction.
Figure 3. Boat conformation of the six-membered rings in 2 (left) and
3 (right).
terminal P−C bond lengths (1.709(2) to 1.715(2) Å) indicate
double bond character but are yet longer than in reported
phosphaalkenes (ca. 1.68 Å).5,6 Furthermore, the C−N bond
lengths (ca. 1.35 Å) of the sp2 carbon atoms (C1/C2) are
The molecular structure of 4 (Figure 4) reveals that a
rearrangement of 1 occurred during the reaction. Density
functional theory (DFT) calculations were performed to gain
Scheme 2. Synthesis of Copper(I) Complex (4)
B
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proton to a terminal P atom) to give the intermediate I2 (ΔE =
+3.9 kJ/mol). Subsequently, an intramolecular rearrangement
takes place that includes the formation of the P−P bond and
the elimination of a cyclohexyl isocyanide, which coordinates at
the CuI cation leading to I3 (ΔE = +28.4 kJ/mol).
Interestingly, the sum of all energies in this process going
from 1 to I3 is almost zero. Dimerization of I3 finally gives
product 4 (ΔE = −117.6 kJ/mol). However, no transition state
was found for the transformation from I2 to I3. We expect that
at least two transition states are involved in this reaction step.
The copper atom in complex 4 is coordinated in a distorted
tetrahedral fashion. The P1−Cu1−P3 bond angle of the five-
membered ring is much smaller (89.04(3)°) than the other
bond angles (C1−P3−Cu1 (112.67(9)°), P2−C1−P3
(118.8(1)°), C1−P2−P1 (102.21(9)°) and P2−P1−Cu1
(105.53(3)°). The five-membered ring formed by P2−P1−
Cu1−P3−C1 exhibits a twist conformation. The P−P
(2.194(1) Å) and the P2−C1 (1.829(3) Å) bonds are in the
range of single bonds (P−P 2.21 Å,16 P−C 1.85 Å5k,8), while
the P3−C1 bond length of 1.747(3) Å indicates multiple bond
character but is longer than reported for phosphaalkenes.5,6
The C1−N1 bond length is 1.328(3) Å, which is shorter than a
carbon−nitrogen single bond,9 suggesting conjugation of the
lone pair of electrons at nitrogen with the PC bond. The
Cu1−P1 (2.2932(7) Å) and the Cu1−P3/Cu1−P3′ bond
lengths (2.3380(7) and 2.3756(8) Å) are comparable to other
copper(I) phosphine complexes.17 The molecule resides on a
crystallographic inversion center, which is located in the center
of the central planar Cu2P2 ring. The Cu1···Cu1′ distance
(2.7708(6) Å) is shorter than the sum of the van der Waals
radii (rCu = 1.96 0.10 Å),8,18a−f and the Cu1−P3−Cu1′ bond
angle is very small (72.00(2)°), indicating a weak cuprophilic
interaction,8,17,18 which is also supported by the calculated
Figure 4. Molecular structure of the dication of 4. Thermal ellipsoids
are set at 50% probability (two counterions (PF6 ), H atoms other
−
than N−H, P−H, and disordered THF molecules are omitted for
clarity). Selected bond lengths [Å] and bond angles [deg]: P1−P2
2.194(1), P2−C1 1.829(3), P3−C1 1.747(3), C1−N1 1.328(3), P1−
Cu1 2.2932(7), P3−Cu1 2.3380(7), P3−Cu1′ 2.3756(8), Cu1−C35
1.926(3), N2−C35 1.152(3), N1−C1−P2 117.6(2), N1−C1−P3
122.4(2), P2−C1−P3 118.8(1), C1−P2−P1 102.21(9), P2−P1−Cu1
105.53(3), P1−Cu1−P3 89.04(3), C1−P3−Cu1 112.67(9), Cu1−
P3−Cu1′ 72.00(2), P3−Cu1−P3′ 108.00(2), P3−Cu1−C35
117.69(8), P1−Cu1−C35 120.26(3), P3′−Cu1−C35 119.09(9),
P3′−Cu1−P1 97.45(3).
Lowdin and Mayer Cu−Cu bond order of 0.1904 and 0.1947,
̈
respectively.8
31P{1H} NMR spectrum of 4 in CDCl3 displays a broad
signal (−80.3 ppm at room temperature (RT) and −80.8 ppm
at −50 °C), a broad doublet (−45.5 ppm at RT and −47.6 ppm
at −50 °C) and a broad triplet (−24.6 ppm at RT and −28.4
ppm at −50 °C) with one sharp septet (−144.3 ppm at RT and
−144.5 ppm at −50 °C) for the counterion hexafluorophos-
phate, at room temperature as well as at lower temperature
insight into the mechanism of the unusual rearrangement (for
details see the Supporting Information). The formation of 4
can be rationalized as follows (Scheme 3): The first step of the
reaction is the coordination of the CuI cation by the terminal
phosphorus atoms of 1 leading to the formation of I1 (ΔE =
−32.8 kJ/mol), which is analogous to the chelate complexes 2
and 3. The CuI ion facilitates a tautomerization reaction (N−H
Scheme 3. Proposed Mechanism of Formation of Copper(I) Complex 4
C
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1
mmol) in THF (15 mL) at −78 °C. The color of the solution changed
to dark red after 15 min. The red solution was warmed to room
temperature over several hours and stirred overnight. The solvent was
removed under vacuum, and the resulting red solid was extracted with
Et2O (15 mL). Dark red prisms of 3 appeared after 1 d at room
(−50 °C). The H NMR spectrum in CDCl3 also displays
broad signals for the methyl protons and the aromatic protons
at room temperature; however, these signals are getting sharper
at lower temperature (−50 °C), which indicates dynamic
behavior (monomer−dimer) of complex 4 in solution. The
infrared spectrum of 4 shows sharp bands at 3302 cm−1 (ν(N−
H)) and 2109 cm−1 (ν(CN)), for the coordinated cyclohexyl
isocyanide ligand,19 and at 2378 cm−1 (ν(P−H)) for the
secondary phosphine.
1
temperature. Yield: 0.255 g (95%). H NMR (C6D6, 298 K): δ =
0.26−1.50 (m, 22 H, cyclohexyl protons), 1.95 (s, 3 H, p-CH3 in Mes
of P2), 2.02 (s, 6 H, p-CH3 in Mes of P1/P3), 2.72 (br, 6 H, o-CH3 in
Mes of P2), 2.83−2.86 (bs, 12 H, o-CH3 in Mes of P1/P3), 4.49 (m, 2
H, NH), 6.75 (s, 4 H, m-H in Mes of P1/P3), 6.78 (s, 2 H, m-H in
Mes of P2) ppm. 13C{1H} NMR (C6D6, 298 K): δ = 21.1−23.0 (Mes-
CH3), 25.0−33.8 (cyclohexyl carbons), 56.7 (cyclohexyl carbon,
NCH), 129.0−130.5 (m-CH in Mes), 134.6 (ipso-C in Mes), 140.0−
142.2 (C−CH3), 177.6 (t, 2JPC = 6.5 Hz, CO), 178.0 (t, 2JPC = 6.5 Hz,
CO), 200.8 (m, PC), 206.3 (m, PC) ppm. 31P{1H} NMR (C6D6,
CONCLUSION
■
1,3,5-Triphospha-1,4-pentadiene-2,4-diamine (1) reacts with
group 6 metal(0) carbonyls (metal = molybdenum and
tungsten) to give chelate complexes in which only the terminal
phosphorus atoms coordinate to the metal center. In contrast,
the reaction with copper(I) leads to an intramolecular
rearrangement of 1 with P−P bond formation and elimination
of cyclohexyl isocyanide. Further reactivity studies of 1 are
underway.
2
2
298 K): δ = 17.5 (t, 1 P, JPP = 141 Hz, P2), 55.8 (d, 2 P, JPP = 141
Hz, JPW = 236 Hz, P1/P3) ppm. FT-IR (KBr, cm−1): ν
̃
= 3321 (s,
1
NH), 2922 (m, CH, sp3), 2008 (s, CO), 1891 (s, CO), 1857 (s, CO),
1601 (m, PC). MS (ESI-LRMS, pos, n-hexane/CH3CN): m/z =
966.3 [M]+, 938.3 [M − CO]+. Anal. Calcd: C45H57N2O4P3W
(966.72), calcd. C 55.91, H 5.94, N 2.90; found C 56.29, H 6.16, N
2.61%. mp 184−186 °C.
4: A suspension of [Cu(CH3CN)4]PF6 (0.125 g, 0.335 mmol) in
THF (15 mL) was added dropwise to a solution of 1 (0.220 g, 0.328
mmol) in THF (15 mL) at −78 °C. The color of the solution changed
to bright orange after 15 min. The orange solution was warmed to
room temperature over several hours and stirred overnight. The
solution was concentrated to 15 mL and layered with n-hexane (5
mL). Orange prisms of 4 appeared after 1 d at room temperature.
Yield: 0.272 g (94%). 1H NMR (CDCl3, 298 K): δ = 0.31−3.14 (m, 44
H, cyclohexyl protons), 2.24−2.62 (54 H, CH3 in Mes), 4.27 (bs, 2 H,
EXPERIMENTAL SECTION
■
General Remarks. All experiments were performed under dry
nitrogen. Only the addition of metal complexes to a solution of 1 was
performed in the dark. Solvents (tetrahydrofuran (THF) and Et2O)
were dried and freshly distilled under nitrogen and kept over a
potassium mirror or molecular sieves (4 Å). The NMR spectra were
recorded at 25 °C with a Bruker Avance DRX 400 spectrometer (1H
NMR: 400.13 MHz, 13C NMR: 100.16 MHz, 31P NMR: 161.97
MHz). Tetramethylsilane (TMS) was used as internal standard for 1H
NMR spectra. 13C and 31P NMR experiments were referenced to TMS
on the Ξ scale.20 In all 31P NMR experiments, 85% H3PO4 in water
was used as external standard. Electrospray ionization mass
spectrometry (ESI-MS) measurements were performed with a Bruker
Daltonics FT-ICR-MS spectrometer (Type APEX II, 7 T). Elemental
analyses were performed with a Heraeus VARIO EL oven. Infrared
spectra were recorded with a spectrometer from PerkinElmer (System
2000) in the range from 4000 to 400 cm−1. The melting points
(Gallenkamp) were determined in a capillary tube. Ligand 1,8
1
NH), 6.68 (br, 2 H, PH, JPH = 157 Hz), 6.46−7.01 (12 H, m-H in
1
Mes) ppm. H NMR (CDCl3, 223 K): δ = 0.36−3.10 (m, 44 H,
cyclohexyl protons), 0.95−2.76 (54 H, CH3 in Mes), 4.10 (br, 2 H,
NH), 6.45 (bd, 2 H, PH), 6.39−7.04 (12 H, m-H in Mes) ppm.
13C{1H} NMR (CDCl3, 298 K): δ = 21.1−24.7 (Mes-CH3), 25.6−32.2
(cyclohexyl carbons), 54.4−60.4 (cyclohexyl carbon, NCH), 115.3−
128.5 (ipso-C in Mes), 129.9−131.2 (m-CH in Mes), 137.8−145.3
(C−CH3, CyNC), 195.7 (PC) ppm. 31P{1H} NMR (CDCl3, 298
K): δ = −24.6 (bt, 1 P, P2), −45.5 (bd, 1 P, P1), −80.3 (br, 1 P, P3),
−144.3 (sept, 1 P, 1JPF = 712.7 Hz, PF6) ppm. 31P{1H} NMR (CDCl3,
223 K): δ = −28.4 (bt, 1 P, P2), −47.6 (bd, 1 P, P1), −80.8 (br, 1 P,
[Mo(CO)4(nbd)],21 and [Cu(CH3CN)4]PF6 were synthesized
22
P3), −144.5 sept, 1 P, PF6, 1JPF = 713 Hz) ppm. FT-IR (KBr, cm−1): ν
̃
according to the literature. [W(CO)4(CH3CN)2] was synthesized by
= 3301 (s, NH), 2934 (m, CH, sp3), 2190 (s, CN), 2378 (w, P−H),
1603 (s, PC). MS (ESI-HRMS, pos, CHCl3/CH3CN): m/z =
1185.4956 [M − 2 PF6 − Cu − 2 CyNC]+, 733.3011 [monomer −
PF6]+, 624.2120 [monomer − PF6 − CyNC]+. Anal. Calcd:
C82H114Cu2F12N4P8·4C4H8O (2047.02), calcd. C 57.51, H 7.19, N
2.74; found C 56.25, H 6.90, N 2.73%. mp 177−180 °C.
modification of the known literature procedure.23
2: A solution of [Mo(CO)4(nbd)] (0.091 g, 0.303 mmol) in THF
(15 mL) was added dropwise to a solution of 1 (0.200 g, 0.298 mmol)
in THF (15 mL) at −78 °C. The color of the solution changed to
bright orange after 15 min. The orange solution was warmed to room
temperature over several hours and stirred overnight. The solvent was
removed under vacuum, and the resulting orange solid was extracted
with Et2O (15 mL). Dark orange prisms of 2 appeared after 1 d at
room temperature. Yield: 0.255 g (93%). 1H NMR (C6D6, 298 K): δ =
0.26−1.51 (m, 22 H, cyclohexyl protons), 1.95 (s, 3 H, p-CH3 in Mes
of P2), 2.02 (s, 6 H, p-CH3 in Mes of P1/P3), 2.71 (br, 6 H, o-CH3 in
Mes of P2), 2.83−2.87 (bs, 12 H, o-CH3 in Mes of P1/P3), 4.56 (m, 2
H, NH), 6.76 (s, 4 H, m-H in Mes of P1/P3), 6.78 (s, 2 H, m-H in
Mes of P2) ppm. 13C{1H} NMR (C6D6, 298 K): δ = 21.1−23.2 (Mes-
CH3), 25.0−33.8 (cyclohexyl carbons), 56.7 (cyclohexyl carbon,
NCH), 129.0−130.4 (m-CH in Mes), 135.4 (m, ipso-C in Mes)
139.8−142.1 (C−CH3), 179.5 (br, CO), 180.0 (br, CO), 208.7 (m,
PC), 216.0 (m, PC) ppm. 31P{1H} NMR (C6D6, 298 K): δ = 14.2
X-ray data were collected with a Gemini CCD diffractometer
(Rigaku Inc.), λ(Mo Kα) = 0.710 73 Å, T = 130(2) K, empirical
absorption corrections with SCALE3 ABSPACK.24 The structures
were solved by dual space methods with SHELXT-2014. Structure
refinement was done with SHELXL-201725 by using full-matrix least-
squares routines against F2. With the exception of NH and PH
fragments all hydrogen atoms were calculated on idealized positions.
The pictures were generated with the program Diamond.26 CCDC
1814283 (2), CCDC 1814284 (3), and CCDC 1814285 (4) contain
the supplementary crystallographic data for this paper. Additional
crystallographic information is available in the Accession Codes.
Crystal Data for 2. C49H67MoN2O5P3, M = 952.89, triclinic, space
2
2
group P1, a = 12.3053(4) Å, b = 12.7264(4) Å, c = 18.0638(4) Å, α =
(t, 1 P, JPP = 142 Hz, P2), 80.5 (d, 2 P, JPP = 142 Hz, P1/P3) ppm.
FT-IR (KBr, cm−1): ν = 3323 (s, NH), 2923 (m, CH, sp3), 2013 (s,
̅
99.842(2)°, β = 95.997(2)°, γ = 114.441(3)°, V = 2488.6(1) Å3, Z = 2,
ρcalcd = 1.272 Mg·m−3, μ(Mo Kα) = 0.405 mm−1, θmax = 32.68°, R =
0.0589, Rw = 0.1082 (all data), 16 729 independent reflections, 558
parameters, 7 restraints, residual electron density 1.658 and −0.833 e·
Å−3.
̃
CO), 1902 (s, CO), 1860 (s, CO), 1601 (m, PC). MS (ESI-HRMS,
pos, CH3Cl/CH3CN): m/z = 881.3 [M + H]+, 1781.5196 [2 M +
Na]+. Anal. Calcd: C45H57MoN2O4P3·C4H10O (952.97), calcd. C
61.76, H 7.09, N 2.94; found C 61.76, H 6.77, N 2.94%. mp 178−181
°C.
Crystal Data for 3. C45H57N2O4P3W, M = 966.68, monoclinic,
3: A solution of [W(CO)4(CH3CN)2] (0.097 g, 0.256 mmol) in
THF (15 mL) was added dropwise to a solution of 1 (0.170 g, 0.253
space group P21/n, a = 15.4814(1) Å, b = 20.1559(1) Å, c =
15.4985(1) Å, β = 111.699(1)°, V = 4493.48(5) Å3, Z = 4, ρcalcd
=
D
DOI: 10.1021/acs.inorgchem.8b00067
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
1.429 Mg·m−3, μ(Mo Kα) = 2.720 mm−1, θmax = 37.38°, R = 0.0463,
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Crystal Data for 4. C98H146Cu2F12N4O4P8, M = 2047.02,
monoclinic, space group P21/n, a = 19.0776(5) Å, b = 13.5866(4)
hetero- and homobimetallic complexes. Coord. Chem. Rev. 2009, 253,
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Å, c = 20.0700(5) Å, β = 102.835(3)°, V = 5072.2(2) Å3, Z = 2, ρcalcd
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parameters, 73 restraints, residual electron density 0.754 and −0.583
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ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.inorg-
chem.8b00067.
■
S
Molecular structure of 3, detailed theoretical calculations
of the reaction mechanism for the formation of complex
4, multinuclear NMR and ESI mass spectra for 2, 3, and
4 (PDF)
Reactivity to forming chelate complexes; characterization
of transition-metal complexes (PDF)
Accession Codes
CCDC 1814283−1814285 contain the supplementary crystal-
lographic data for this paper. These data can be obtained free of
charge via www.ccdc.cam.ac.uk/data_request/cif, or by email-
ing data_request@ccdc.cam.ac.uk, or by contacting The
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
AUTHOR INFORMATION
Corresponding Author
*E-mail: hey@uni-leipzig.de.
ORCID
Evamarie Hey-Hawkins: 0000-0003-4267-0603
Notes
The authors declare no competing financial interest.
■
9515. (p) Pfaltz, A.; Blankenstein, J.; Hilgraf, R.; Hormann, E.;
̈
McIntyre, S.; Menges, F.; Schonleber, M.; Smidt, S. P.; Wustenberg,
̈
̈
B.; Zimmermann, N. Iridium-Catalyzed Enantioselective Hydro-
genation of Olefins. Adv. Synth. Catal. 2003, 345, 33−43. (q) Espinet,
P.; Soulantica, K. Phosphine-pyridyl and related ligands in synthesis
and catalysis. Coord. Chem. Rev. 1999, 193−195, 499−556. (r) Slone,
C. S.; Weinberger, D. A.; Mirkin, C. A. In Progress in Inorganic
Chemistry; Karlin, K. D., Ed.; Wiley: New York, 1999; Vol. 48, pp
233−350. (s) Zhang, S.; Pattacini, R.; Braunstein, P. In Advances in
Organometallic Chemistry and Catalysis: The Silver/Gold Jubilee
International Conference on Organometallic Chemistry Celebratory
Book; Pombeiro, A. J. L., Ed.; Wiley: Hoboken, NJ, 2013; pp 185−
198. (t) Carroll, M. P.; Guiry, P. J. P,N ligands in asymmetric catalysis.
Chem. Soc. Rev. 2014, 43, 819−833.
ACKNOWLEDGMENTS
■
Support from the Deutscher Akademischer Austauschdienst
(DAAD-GSSP doctoral grant for A.K.A.), the Studienstiftung
des deutschen Volkes (doctoral grant for T.G.), and the
Graduate School BuildMoNa is gratefully acknowledged. We
thank M.Sc. B. Schwarze for measurement of several NMR
spectra.
(3) (a) Morales-Morales, D.; Jensen, C. M. The Chemistry of Pincer
Compounds; Elsevier: Amsterdam, Netherlands, 2007. (b) van Koten,
G.; Milstein, D. Organometallic Pincer Chemistry; Springer: Heidelberg,
Germany, 2013. (c) van der Boom, M. E.; Milstein, D. Cyclometalated
Phosphine-Based Pincer Complexes: Mechanistic Insight in Catalysis,
Coordination, and Bond Activation. Chem. Rev. 2003, 103, 1759−
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S. Dehydrogenation and Related Reactions Catalyzed by Iridium
Pincer Complexes. Chem. Rev. 2011, 111, 1761−1779. (e) Selander,
DEDICATION
■
Dedicated to Prof. Dr. Wolfgang Weigand on the occasion of
his 60th birthday.
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under vacuum, and the resulting greenish-yellow solid was washed
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