A complete series of halocarbonyl molybdenum PNP pincer complexes - Unexpected differences between NH and NMe spacers Dedicated to Prof. Dr. Maria José Calhorda on the occasion of her 65th birthday.

Article abstract of DOI:10.1016/j.jorganchem.2013.12.018

In the present study a complete series of seven-coordinate neutral halocarbonyl Mo(II) complexes of the type [Mo(PNP^Me-Ph)(CO) ₂X₂] (X = I, Br, Cl, F), featuring the new PNP pincer ligand N,N′-bis(diphenylphosphino)-N,N′-methyl-2,6-diaminopyridine (PNP^Me-Ph), were prepared and fully characterized. The synthesis of these complexes was accomplished by different methodologies depending on the halide ligands. For X = I and Br, [Mo(PNP^Me-Ph)(CO)₂I ₂] and [Mo(PNP^Me-Ph)(CO)₂Br₂] were obtained by reacting [Mo(PNP^Me-Ph)(CO)₃] with stoichiometric amounts of I₂ and Br₂, respectively. Alternatively, these complexes were obtained upon treatment of [MoX ₂(CO)₃(CH₃CN)₂] (X = I, Br) with 1 equiv. of PNP^Me-Ph. On the other hand, in the case of X = Cl, [Mo(PNP^Me-Ph)(CO)₂Cl₂] was afforded by the reaction of [Mo(CO)₄(μ-Cl)Cl]₂ with 1 equiv. of PNP^Me-Ph. The equivalent procedure also worked for X = Br. Finally, addition of 1 equiv. of 1-fluoro-2,4,6-trimethylpyridinium tetrafluoroborate to [Mo(PNP^Me-Ph)(CO)₃] yielded the analogous fluorine complex [Mo(PNP^Me-Ph)(CO)₂F₂]. The modification of the ligand scaffold by introducing a Me group instead of H changed the properties of the PNP-Ph ligand significantly. While in the present case exclusively neutral seven-coordinate complexes of the type [Mo(PNP^Me-Ph)(CO) ₂X₂] were obtained, with the parent PNP-Ph ligand, i.e., featuring NH spacers, cationic seven-coordinate complexes of the type [Mo(PNP-Ph)(CO)₃X]X were afforded. DFT calculations indicated that the reactions are under thermodynamic control. The structures of representative complexes were determined by X-ray single crystal analyses.

Full text of DOI:10.1016/j.jorganchem.2013.12.018

Journal of Organometallic Chemistry 760 (2014) 74e83
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
A complete series of halocarbonyl molybdenum PNP pincer complexes
e Unexpected differences between NH and NMe spacers
Sara Raquel M.M. de Aguiar a, Berthold Stöger b, Ernst Pittenauer b, Michael Puchberger c,
,
Günter Allmaier b, Luis F. Veiros d, Karl Kirchner a
*
a Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
b Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
c Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
d Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais No. 1, 1049-001 Lisboa, Portugal
a r t i c l e i n f o
a b s t r a c t
Article history:
In the present study a complete series of seven-coordinate neutral halocarbonyl Mo(II) complexes of the
type [Mo(PNPMe-Ph)(CO)2X2] (X ¼ I, Br, Cl, F), featuring the new PNP pincer ligand N,N0-bis(diphenyl-
phosphino)-N,N0-methyl-2,6-diaminopyridine (PNPMe-Ph), were prepared and fully characterized. The
synthesis of these complexes was accomplished by different methodologies depending on the halide
ligands. For X ¼ I and Br, [Mo(PNPMe-Ph)(CO)2I2] and [Mo(PNPMe-Ph)(CO)2Br2] were obtained by reacting
[Mo(PNPMe-Ph)(CO)3] with stoichiometric amounts of I2 and Br2, respectively. Alternatively, these
complexes were obtained upon treatment of [MoX2(CO)3(CH3CN)2] (X ¼ I, Br) with 1 equiv. of PNPMe-Ph.
On the other hand, in the case of X ¼ Cl, [Mo(PNPMe-Ph)(CO)2Cl2] was afforded by the reaction of
Received 16 November 2013
Received in revised form
5 December 2013
Accepted 8 December 2013
Dedicated to Prof. Dr. Maria José Calhorda
on the occasion of her 65th birthday.
[Mo(CO)4(
m
-Cl)Cl]2 with 1 equiv. of PNPMe-Ph. The equivalent procedure also worked for X ¼ Br. Finally,
Keywords:
addition of 1 equiv. of 1-fluoro-2,4,6-trimethylpyridinium tetrafluoroborate to [Mo(PNPMe-Ph)(CO)3]
yielded the analogous fluorine complex [Mo(PNPMe-Ph)(CO)2F2]. The modification of the ligand scaffold
by introducing a Me group instead of H changed the properties of the PNP-Ph ligand significantly. While
in the present case exclusively neutral seven-coordinate complexes of the type [Mo(PNPMe-Ph)(CO)2X2]
were obtained, with the parent PNP-Ph ligand, i.e., featuring NH spacers, cationic seven-coordinate
complexes of the type [Mo(PNP-Ph)(CO)3X]X were afforded. DFT calculations indicated that the re-
actions are under thermodynamic control. The structures of representative complexes were determined
by X-ray single crystal analyses.
Molybdenum complexes
PNP pincer ligands
Carbon monoxide
ESI mass spectrometry
DFT calculations
Ó 2014 Elsevier B.V. All rights reserved.
1. Introduction
ligands are readily available via condensation reactions between
2,6-diaminopyridines and electrophilic chlorophosphines R2PCl.
One of the ways of modifying and controlling the properties of
transition metal complexes is the use of appropriate ligand systems
such as pincer ligands. Usually consisting of a central aromatic
backbone tethered to two two-electron donor groups by different
spacers, this class of tridentate ligands has found numerous ap-
plications in various areas of chemistry, including catalysis, due to
their combination of stability, activity and variability [1]. We are
currently focusing on the synthesis and reactivity of transition
metal PNP pincer complexes where the pincer ligands contain
amine (NH and NR) spacers between the aromatic pyridine ring and
the phosphine moieties [2]. It has to be noted that these type PNP
In a recent study we have begun to investigate the chemistry of
cationic seven-coordinate halocarbonyl molybdenum complexes of
the type [Mo(PNP)(CO)3X]þ (X ¼ I, Br) with PNP pincer ligands
where the central pyridine ring contains NHPR2(R ¼ Ph, iPr) sub-
stituents in the two ortho positions [3]. These complexes were
obtained either by direct oxidation of the Mo(0) complexes
[Mo(PNP)(CO)3] with X2 (X ¼ I, Br) or by treatment of the dimeric
Mo(II) complex[Mo(CO)4(
m
-X)X]2 (X ¼ Cl, Br) with stoichiometric
amounts of a PNP ligand (Scheme 1). It has to be noted that the
formation of halocarbonyl Mo(II) and W(II) complexes of the type
[ML(CO)3X] (M ¼ Mo, W; X ¼ Cl, Br, I; L ¼ neutral or anionic tri-
dentate ligands such as Cp, Cp*, HCpz3, HBpz3) via oxidative addi-
tion of X2 to M(0) complexes [ML(CO)3] is a well-established
reaction [4]. As PNP pincer complexes are concerned, most
recently Templeton and coworkers described the synthesis of a
* Corresponding author. Tel.: þ43 1 58801 163611; fax: þ43 1 58801 16399.
E-mail address: kkirch@mail.tuwien.ac.at (K. Kirchner).
0022-328X/$ e see front matter Ó 2014 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.12.018

S.R.M.M. de Aguiar et al. / Journal of Organometallic Chemistry 760 (2014) 74e83
75
Scheme 1. Formation of cationic seven-coordinate halocarbonyl molybdenum complexes of the type [Mo(PNP)(CO)3X]þ (X ¼ Cl, Br, I).
series of halocarbonyl tungsten pincer complexes featuring the
silazane-based PNP pincer-type ligand HN(SiMe2CH2PPh2)2 [5].
Here we report on the synthesis, characterization and reac-
tivity of a complete series of new halocarbonyl molybdenum(II)
PNP pincer complexes of the type [Mo(PNPMe-Ph)(CO)2X2] (X ¼ I,
Br, Cl, F) where the PPh2 moieties of the PNP ligand are connected
to the pyridine ring via a NMe spacer. It has to be mentioned
that the number of molybdenum (and tungsten) carbonyl fluo-
ride derivatives known is small [5e8]. The modification of
the ligand scaffold by introducing a Me group instead of H
changes the properties of the PNP-Ph ligand significantly. A
rationale for this behavior will be provided by exploratory DFT
calculations [9]. X-ray structures of representative complexes will
be given.
bulkiness of the PR2 moiety (PNP-Ph
<
PNPMe-Ph
>
PNP-
iPr2 < PNPMe-iPr < PNP-tBu2) and decrease from 171.1(8)ꢀ in
[Mo(PNP-Ph)(CO)3] [10] to 166.15(5)ꢀ in [Mo(PNPMe-Ph)(CO)3] (2)
to 166.03(5)ꢀ in [Mo(PNP-iPr)(CO)3] [3a] to 162.93(7)ꢀ in
[Mo(PNPMe-iPr)(CO)3] [3b], and finally to 156.53(4)ꢀ in [Mo(PNP-
tBu)(CO)3] [3a]. Accordingly, the new ligand 2 resembles sterically
the PNP-iPr ligand.
Treatment of 2 with stoichiometric amounts of X2 (X ¼ I, Br) in
CH3CN yields the neutral seven-coordinate complexes [Mo(PNPMe
-
Ph)(CO)2I2] (3a) and [Mo(PNPMe-Ph)(CO)2Br2] (3b) in 81% and 84%
isolated yield (Scheme 2). Alternatively, these complexes were also
obtained by reacting [MoX2(CO)3(CH3CN)2] (X ¼ I, Br) with 1 equiv.
of PNPMe-Ph. The analogous chlorine complex [Mo(PNPMe
-
Ph)(CO)2Cl2] (3c) was afforded by treatment of [Mo(CO)4(m-Cl)Cl]2
in CH3CN with 1 equiv. of PNPMe-Ph in 81% yield. Noteworthy, this
methodology also works very well for the synthesis of 3b. Finally,
addition of 1 equiv. of 1-fluoro-2,4,6-trimethylpyridinium tetra-
fluoroborate, a reagent acting as net source of “Fþ”, to a solution of
[Mo(PNPMe-Ph)(CO)3] in CH2Cl2 yielded the analogous fluorine
complex [Mo(PNPMe-Ph)(CO)2F2] (3d) in 93% isolated yield
(Scheme 3). The long reaction time required (3 days) and the high
yield of this reaction clearly suggest that the BFꢁ4 counterion acts as
an additional fluoride source which has indeed precedence in
molybdenum and tungsten chemistry [11].
2. Results and discussion
We have recently reported the synthesis of molybdenum tri-
carbonyl complexes of the type [Mo(PNP)(CO)3] by reacting
[Mo(CO)3(CH3CN)3] with a series of PNP ligands in high isolated
yields [3]. The same procedure was followed here with the new N-
methylated PNP ligand N,N0-bis(diphenylphosphino)-N,N0-methyl-
2,6-diaminopyridine (PNPMe-Ph) (1) affording [Mo(PNPMe
-
Ph)(CO)3] (2) in 92% yield. The new PNP ligand 1 was prepared in a
modified two-step procedure as reported elsewhere [3a]. In addi-
tion to the spectroscopic characterization, the solid-state structure
of 2 was determined by single-crystal X-ray diffraction. A structural
view is depicted in Fig. 1 with selected bond distances given in the
caption. The coordination geometry around the molybdenum
center corresponds to a distorted octahedron with a PeMoeP bond
angle of 155.48(1)ꢀ. The carbonyl-Mo-carbonyl angles of the CO
ligands trans to one another typically vary strongly with the
All complexes are thermally robust red to yellow solids which
are air stable in the solid state but slowly decompose in solution.
Characterization was accomplished by elemental analysis and by 1H
and 31P{1H} NMR, and IR spectroscopy. Due the poor solubility and
thus the low concentration of the complexes, quaternary carbons
could not be detected or was completely precluded (3d). Thus
solid-state 13C NMR spectra were recorded giving rise to two
characteristic low-field resonances at 228.5 and 218.2 ppm for 3a,
244.8 and 225.7 ppm for 3b, 257.6 and 215.1 ppm for 3c, and 250.4
and 214.3 ppm for 3d assignable to the carbonyl carbon atoms trans
and cis to the pyridine nitrogen, respectively. The 31P{1H} NMR
spectrum of complexes 3aec gave rise to singlets at 141.3, 145.2,
and 147.2 ppm, respectively, while for 3d a triplet resonance
centered at 155.7 ppm with a 2JPF coupling constant of 41.7 Hz was
observed. These chemical shifts are obviously directly related to the
increasing electronegativity of the halide ligands. Complexes 3ae
d exhibited two bands in the range of 1946e1858 cmꢁ1 in the IR
spectrum (cf 2143 cmꢁ1 in free CO) for the mutually cis CO ligands
assignable to the symmetric and asymmetric CO stretching fre-
quencies, respectively. The appearance of two sets resonances in
the IR spectrum of 3c, which are 26 and 16 cmꢁ1 apart, may be due
to intermolecular interactions, e.g., C^O/CleMo bonds, in the
solid state [12].
Moreover, all complexes were also investigated by means of ESI-
MS (Table 1). A solution of complexes 3aed in MeOH in the pres-
ence of the corresponding sodium salts NaX (X ¼ I, Br, Cl, F) was
subjected to ESI-MS analysis in the positive-ion mode. Under so
called “soft ionization” conditions, the most abundant signals
observed at m/z are 901.88, 805.91, and 718.01, respectively, which
Fig. 1. Structural view of [Mo(PNPMe-Ph)(CO)3]$CH2Cl2 (2$CH2Cl2) showing 50% ther-
mal ellipsoids (hydrogen atoms and solvent omitted for clarity). Selected bond lengths
(Å) and bond angles (ꢀ): Mo1-C32 2.020(1), Mo1-C331.957(1), Mo1-C34 2.030(1), Mo1-
P1 2.3816(4), Mo1-P2 2.3890(4), Mo-N1 2.246(1), P1-Mo1-P2 155.48(1), N1-Mo1-
C33176.22(5), C32-Mo1-C34166.15(5).

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S.R.M.M. de Aguiar et al. / Journal of Organometallic Chemistry 760 (2014) 74e83
Scheme 2. Formation of neutral seven-coordinate halocarbonyl molybdenum complexes of the type [Mo(PNP)(CO)2X2] (X ¼ F, Cl, Br, I).
Scheme 3. Synthesis of the fluoride complex [Mo(PNPMeePh)(CO)2F2] (3d).
correspond to the sodiated complexes [Mo(PNPMe-Ph)(CO)X2]
([M þ Na ꢁ CO]þ) where one CO ligand is dissociated suggesting
that one CO ligand is labile (vide infra). Further abundant fragments
are [Mo(PNPMe-Ph)(CO)X]þ ([M-(COþNaX)]þ) and [Mo(PNPMe-Ph)
X]þ ([M-(2CO þ NaX)]þ) as shown in Scheme 4. Corresponding
positive-ion ESI full scan mass and MS/MS (low energy CID) spectra
of 3b are depicted in Fig. 2. For the fluoride complex 3d a different
behavior was found. This complex forms after loss of CO and NaF
exclusively the cationic fragment [Mo(PNPMe-Ph)(CO)F]22þ ([M-
(CO þ NaF)]22þ) which is apparently a doubly charged dimer based
on isotope spacings (0.5 Da). Higher molecular mass fragments
were not observed in this particular case.
In addition to the spectroscopic characterization, the solid-state
structures of 3a, 3b, and 3c were determined by single-crystal X-ray
diffraction. Structural diagrams are depicted in Figs. 3e5 with
selected bond distances given in the captions. The coordination
geometry around the molybdenum center may be described as a
trigonal monocapped antiprism with C32-O1 as capping ligand
(Fig. 4b).
The crystal structure shows the tridentate PNP ligand bound
meridionally with two carbonyl and two halide ligands filling the
remaining four sites. The metal-CO bond lengths in the three
complexes average to 1.97 Å (1.93e2.01 Å). The P1-Mo1-P2 angles
in 3aec increase from 111.84(2) to 118.46(3) to 120.18(2)ꢀ,
Table 1
Elemental compositions and calculated mass values of intact compounds 1, 2, 3aed and the two most abundant ions related to the sodiated molecules ([M þ Na ꢁ CO]þ,
[M ꢁ (CO þ NaX)]þ where X ¼ F, Cl, Br, I).
Compound
Elemental composition/Molecular weighta
Elemental composition
Elemental composition
1
C31H29N3P2
505.18
[C31H30N3P2]þ
[M þ H]þ ¼ 506.19
2
C34H29Mo1N3O3P2
[C34H29Mo1N3O3P2Na1]þ
[M þ Na]þ ¼ 704.07
681.08
[C33H29Mo1N3O2P2Na1]þ
[M þ Na ꢁ CO]þ ¼ 676.07
[C32H29I2Mo1N3O1P2Na1]þ
[M þ Na ꢁ CO]þ ¼ 901.88
[C32H29Br2Mo1N3O1P2Na1]þ
[M þ Na ꢁ CO]þ ¼ 805.91
[C32H29Cl2Mo1N3O1P2Na1]þ
[M þ Na ꢁ CO]þ ¼ 718.01
[C64H58F4Mo2N6O2P4Na2]2þ
[M þ Na ꢁ CO]þ ¼ 686.07b
3a
3b
3c
3d
C
33H29I2Mo1N3O2P2
906.88
33H29Br2Mo1N3O2P2
810.92
33H29Cl2Mo1N3O2P2
723.02
33H29F2Mo1N3O2P2
691.08
[C32H29I1Mo1N3O1P2]þ
[M ꢁ (CO þ NaX)]þ ¼ 751.99
[C32H29Br1Mo1N3O1P2]þ
[M ꢁ (CO þ NaX)]þ ¼ 704.00
[C32H29Cl1Mo1N3O1P2]þ
C
C
[M ꢁ (CO þ NaX)]þ ¼ 660.05
C
[C64H58F2Mo2N6O2P4]2þ
[M ꢁ (CO þ NaX)]þ ¼ 644.08
a
Mass calculations are based on the lowest mass molybdenum isotope (92Mo) and monoisotopic values.
Not detected.
b

S.R.M.M. de Aguiar et al. / Journal of Organometallic Chemistry 760 (2014) 74e83
77
Scheme 4. Fragmentation pattern of [Mo(PNPMeePh)(CO)2X2] complexes observed in the ESI-MS experiments and the DFT calculated energy balance for X ¼ Br.
respectively, while the corresponding X1-Mo1-X2 and C32-Mo1-
C33 angles are essentially independent of the nature of the halide
being 82.27(1), 80.56(2) and 81.07(2)ꢀ, and 73.60(8), 74.3(2) and
72.92(7)ꢀ, respectively. In all complexes the molybdenum center is
significantly bent out of the least squares plane defined by the
atoms of the pyridine ring (N1, C1eC5) by 0.687(3), 0.788(5), and
0.632(3) Å.
The different reactivity toward halogen (Br2) shown by the tri-
carbonyl complexes, [Mo(PNP)(CO)3], with different PNP ligands
was investigated by means of DFT calculations (see Computational
details). When the spacer in those ligands is NH (ligand PNP-Ph) the
outcome of the reaction is a cationic complex with one bromine as
counter ion that is, thus, expelled from the metal coordination
sphere. On the other hand, in the case of PNPMe-Ph, that has NMe as
spacer in both arms of the pincer ligand, the reaction product is the
neutral complex with both bromine ligands coordinated to the
metal and with loss of one of the carbonyl ligands of the parent
species. The energy balances calculated for the reactions are pre-
sented in Scheme 5 for the complexes with the two types of PNP
ligands, PNP-Ph and PNPMe-Ph. Formation of the cationic
Fig. 2. Positive-ion ESI full scan mass spectrum of [Mo(PNPMe-Ph)(CO)2Br2](3b) (A) and corresponding MS/MS (low energy CID)-spectrum of in-source-generated [M þ Na ꢁ CO]þ
precursor ions (B). Inset shows the calculated and measured isotopic pattern of [M þ Na ꢁ CO]þ. In both spectra only signals containing the Mo-isotope of highest abundance (98Mo)
are annotated.

78
S.R.M.M. de Aguiar et al. / Journal of Organometallic Chemistry 760 (2014) 74e83
Fig. 3. (a) Structural view of [Mo(PNPMe-Ph)(CO)2l2]$CD2Cl2 (3a$CD2Cl2) showing 50% thermal ellipsoids (hydrogen atoms and solvent omitted for clarity). Selected bond lengths (Å)
and bond angles (ꢀ): Mo1-l1 2.8888(5), Mo1-l22.8911(5), Mo1-P1 2.4364(7), Mo1-P2 2.4181(6), Mo-N1 2.276(2), Mo-C32 1.937(2), Mo-C33 1.991(2); P1-Mo1-P2 111.84(2), N1-Mo1-
l1 94.11(4), N1-Mo1-l2 88.10(4), N1-Mo1-C32 122.64(7), N1-Mo1-C33 124.49(7), l1-Mo1-l2 82.27(1), C32-Mo1-C33 73.60(8).(b) Side view of 3a (hydrogen atoms, most phenyl
carbon atoms, and solvent omitted for clarity).
complexes [Mo(PNPR-Ph)(CO)3Br]Br is presented on the left side,
while the reaction that forms the neutral species, [Mo(PNPR-
Ph)(CO)2Br2], with loss of CO is shown on the right side of Scheme 5
(R ¼ H or Me).
approaches one CeH of the pyridine ring (dH-Br ¼ 2.28 Å) in the ion
pair. The NH/Br H-bond stabilizes the product with NH spacers on
the PNP ligand, and hints that that interaction may play a role
during the course of Br2 addition to the initial tricarbonyl complex,
[Mo(PNP-Ph)(CO)3], assisting the loss of Brꢁ from the metal coor-
dination sphere, and leading to the observed product.
The energy balances in Scheme 5 show that the most stable
product is obtained in each case. For the complex with PNP-Ph
formation of the cationic complex [Mo(PNP-Ph)(CO)3Br]Br is
more favorable than formation of the neutral species [Mo(PNP-
Ph)(CO)2Br2] by 16 kcal/mol. Conversely, in the case of the complex
with PNPMe-Ph the neutral complex 3b is the most favorable
product by 9 kcal/mol.
For the system with PNPMe-Ph (R ¼ Me), formation of the
neutral species is the most favorable process. In fact, that reaction is
4 kcal/mol more favorable than the equivalent reaction in the case
of the PNP-Ph species (R ¼ H). This stability difference, although
rather small, can still be traced to the bonding in the corresponding
[Mo(PNPR-Ph)(CO)2Br2] complexes (R ¼ H or Me). In fact, the co-
ordination of the PNPMe-Ph ligand in 3b is stronger than the one
observed for the PNP ligand with R ¼ H in the analogous complex.
This is most clearly seen in the MoeN(py) bonds, with distances of
2.28 and 2.32 Å in the heptacoordinated complexes with R ¼ Me
(3b) and R ¼ H, respectively. The corresponding Wiberg indices
(WI) [13] confirm this result indicating a stronger MoeN(py) bond
in complex 3b (WI ¼ 0.29), when compared to the equivalent bond
in [Mo(PNP-Ph)(CO)2Br2] (R ¼ H, WI ¼ 0.27). The charge distribu-
tion (NPA, see Computational details) calculated for the two
The results above indicate that the reactions are under ther-
modynamic control and this conclusion is further supported by a
closer look into the bonding of the relevant species. In fact, for the
cationic complexes, the corresponding reaction (left side of Scheme
5) is more favorable by 21 kcal/mol in the case of the PNP-Ph ligand
(R ¼ H) compared to the system with PNPMe-Ph (R ¼ Me). The main
structural difference between the two products is the existence of a
strong H-bond, NH/Br (dH-Br ¼ 2.01 Å), in [Mo(PNP-Ph)(CO)3Br]Br
that, naturally, is absent in the corresponding product with R ¼ Me.
In the case of [Mo(PNPMe-Ph)(CO)3Br]Br, the bromide ion
Fig. 4. (a) Structural view of [Mo(PNPMe-Ph)(CO)2Br2]$3CDCl3 (3b$3CDCl3) showing 50% thermal ellipsoids (hydrogen atoms and solvent molecules omitted for clarity). Selected
bond lengths (Å) and bond angles (ꢀ): Mo1-Br1 2.6887(6), Mo1-Br22.6537(5), Mo1-P1 2.429(1), Mo1-P2 2.422(1), Mo-N1 2.249(3), Mo-C32 1.929(4), Mo-C33 2.016(4); P1-Mo1-P2
118.46(3), N1-Mo1-Br1 92.01(8), N1-Mo1-Br2 87.46(7), N1-Mo1-C32 120.5(2), N1-Mo1-C33 165.2(2), Br1-Mo1-Br2 80.56(2), C32-Mo1-C33 74.3(2).(b) Structural view of the inner
coordination sphere of 3b emphasizing the trigonal monocapped antiprism with the C32-O1 ligand as capping ligand.

S.R.M.M. de Aguiar et al. / Journal of Organometallic Chemistry 760 (2014) 74e83
79
Ph)(CO)2X2] (X ¼ I, Br, Cl, F) were prepared and fully characterized.
The synthesis of these complexes was accomplished by different
methodologies depending on the halide ligands. The modification
of the ligand scaffold by introducing a Me group instead of H
changes the properties of the PNP ligand significantly. In fact, the
PNPMe-Ph ligand is sterically more demanding than the PNP-Ph
ligand which is apparent from the carbonyl-Mo-carbonyl angles
of the CO ligands trans to one another being 171.1(8)ꢀ in [Mo(PNP-
Ph)(CO)3] and166.15(5)ꢀ in [Mo(PNPMe-Ph)(CO)3]. While in the
present case exclusively neutral seven-coordinate complexes of the
type [Mo(PNPMe-Ph)(CO)2X2] were obtained, with the parent PNP-
Ph ligand, i.e., featuring NH spacers, cationic seven-coordinate
complexes of the type [Mo(PNP-Ph)(CO)3X]X were afforded. DFT
calculations indicate that the most stable product is obtained in
each case and, thus, the reaction is under thermodynamic control.
The structures of representative complexes were determined by X-
ray single crystal analyses.
Fig. 5. Structural view of [Mo(PNPMe-Ph)(CO)2Cl2]$1.5CD2Cl2 (3c$1.5CD2Cl2) showing
50% thermal ellipsoids (hydrogen atoms and solvent molecules omitted for clarity).
Selected bond lengths (Å) and bond angles (ꢀ): Mo1-Cl1 2.5424(7), Mo1-Cl22.5031(8),
Mo1-P1 2.4253(9), Mo1-P2 2.4259(8), Mo-N1 2.248(1), Mo-C32 1.950(2), Mo-
C331.990(2); P1-Mo1-P2 120.18(2), N1-Mo1-Cl192.20(4), N1-Mo1-Cl2 86.96(3), N1-
Mo1-C33117.00(6),
C3372.92(7).
N1-Mo1-C32169.96(6),
Cl1-Mo1-Cl281.07(2),
C32-Mo1-
4. Experimental
4.1. General
complexes corroborates that result. The PNPMe-Ph ligand in 3b is
slightly more positive (CPNP ¼ 1.16) than the PNP-Ph ligand the
corresponding complex (CPNP ¼ 1.12), while the opposite happens
with the metal atom, that is, the Mo is electron richer in 3b
(CMo ¼ ꢁ0.60) than the metal atom in [Mo(PNP-Ph)(CO)2Br2]
(CMo ¼ ꢁ0.57). This indicates that there is a stronger electron
All manipulations were performed under an inert atmosphere of
argon by using Schlenk techniques or in a MBraun inert-gas glo-
vebox. The solvents were purified according to standard procedures
[14]. The deuterated solvents were purchased from Aldrich and
dried over
[Mo(CO)4(
4 Å molecular sieves. The precursor complexes
-X)X]2 (X ¼ Cl, Br) and [MoX2(CO)3(CH3CN)2] (X ¼ l, Br)
donation from the pincer ligand to the metal in the case of PNPMe
-
m
were prepared according to the literature [15,16].
Ph (R ¼ Me) and, hence, a stronger coordination and a more stable
molecule in this case.
The fragmentation pattern observed in the MS experiments was
also investigated using DFT through the calculation of the energy
balances for the fragmentation steps involving the most abundant
fragments observed. The values shown in Scheme 4 were obtained
for the bromide system (X ¼ Br) without considering the sodium
ion. Most interestingly, the second step, i.e., loss of one bromide
4.2. Characterization techniques
1H, 13C{1H}, and 31P{1H} NMR spectra were recorded on Bruker
AVANCE-250, AVANCE-300 DPX, and DRX 400 spectrometers. 1H
and 13C{1H} NMR spectra were referenced internally to residual
protio-solvent and solvent resonances, respectively, and are re-
ligand from the bis-bromo mono-carbonyl complex [Mo(PNPMe
-
ported relative to tetramethylsilane (
d
¼ 0 ppm). 31P{1H} NMR
Ph)(CO)Br2] is by far the least favorable of all three corroborating,
thus, the high abundance observed for that particular fragment.
spectra were referenced externally to H3PO4 (85%) (
d
¼ 0 ppm).
All solid-state 13C NMR spectra were recorded on a Bruker
Avance-300 spectrometer (standard bore), equipped with a 4 mm
broad-band MAS probe-head and ZrO2 rotors. The rotational speed
for all experiments was 12 kHz.
3. Conclusion
In the present study a complete series of seven-coordinate
All mass spectrometric measurements were performed on an
neutral halocarbonyl Mo(II) complexes of the type [Mo(PNPMe
-
Esquire 3000plus 3D-quadrupole ion trap mass spectrometer
Scheme 5. Energy balance for the formation of complexes [Mo(PNPePh)(CO)3Br]Br and [Mo(PNPePh)(CO)2Br2].

80
S.R.M.M. de Aguiar et al. / Journal of Organometallic Chemistry 760 (2014) 74e83
(Bruker Daltonics, Bremen, Germany) in positive-ion mode elec-
trospray ionization (ESI-MS). Mass calibration was done with a
commercial mixture of perfluorinated trialkyl-triazines (ES Tuning
Mix, Agilent Technologies, Santa Clara, CA, USA). All analytes were
dissolved in methanol hypergrade for LCeMS Lichrosolv (Merck,
Darmstadt, Germany) to a concentration of roughly 1 mg/mL and
doped with sodium fluoride, sodium chloride, sodium bromide or
sodium iodide (Merck, Darmstadt, Germany) to promote
[M þ Na]þ-adduct ion formation of the neutral molybdenum
complexes as previously described for titanium and zirconium
complexes [17,18]. Direct infusion experiments were carried out
using a Cole Parmer model 74900 syringe pump (Cole Parmer In-
precipitate. In order to purify the crude product filtration with hot
CH3CN was carried out. The resulting white compound was dried
under vacuum. Yield: 3.99 g (54%). Anal. Calcd. for C31H29N3P2
(505.54): C, 73.65; H, 5.78; N, 8.31%. Found: C, 73.79; H, 5.50; N,
8.23%. 1H NMR ( , CDCl3, 20 ꢀC): 7.38e7.44 (m, 21H, Ph, py4), 6.87
d
(d, J ¼ 7.4 Hz, 2H, py3,5), 2.89 (s, 6H, NCH3). 13C{1H} NMR (
d, CDCl3,
20 ꢀC): 159.6 (d, J ¼ 27.4 Hz, 2C, py2,6), 138.4 (t, J ¼ 3.0 Hz, py4),
137.5 (d, J ¼ 16.0 Hz, 4C, Ph1), 132.2 (d, J ¼ 20.8 Hz, 8C, Ph2,6), 129.2
(s, 4C, Ph4), 128.5 (d, J ¼ 5.9 Hz, 8C, Ph3,5), 99.9 (d, J ¼ 21.2 Hz, 2C,
py3,5), 34.1 (d, J ¼ 8.6 Hz, 2C, NCH3). 31P{1H} NMR (
d
, CDCl3, 20 ꢀC):
61.4. ESI-MS (m/z, CH3OH, HCOOH) positive ion: 506.19 [M þ H]þ.
struments, Vernon Hills, IL, USA) at a flow rate of 2
mL/min.
4.3.2. [Mo(PNPMe-Ph)(CO)3] (2)
Full scan and MS2-scans were measured in the mass range m/z
100e1100 with the target mass set to m/z 1000. Further experi-
mental conditions include: dry gas temperature: 150 C; capillary
voltage: ꢁ4 kV; skimmer voltage: 40 V; octapole and lens voltages:
according to the target mass set. Helium was used as buffer gas for
full scans and as collision gas for MS2-scans in the low energy CID
mode. The activation and fragmentation width for tandem mass
spectrometric (MS/MS) experiments was set to 14 Da to cover the
entire isotope cluster for fragmentation. The corresponding frag-
mentation amplitude ranged from 0.4 to 0.6 V in order to keep a
low abundant precursor ion intensity in the resulting spectrum. As
precursor ions for tandem mass spectrometric experiments only
the ions [M þ Na ꢁ CO]þ and [M ꢁ (CO þ NaX)]þ, where X ¼ F, Cl, Br
or I, could be selected as precursor ions. Ions containing two car-
bonyls coordinated with molybdenum could not be detected. All
mass calculations are based on the lowest mass molybdenum
isotope (92Mo-isotope). It should also be mentioned here that the
sodium halides had to correspond to the halide content of the
molybdenum complex as an easy exchange between different ha-
lides in the analyte solution was observed obscuring correct mass
assignments of the analytes. Mass spectra and tandem mass spectra
were averaged during data acquisition time of 1e2 min and one
analytical scan consisted of five successive microscans resulting in
50 and 100 analytical scans, respectively, for the final mass
spectrum.
A suspension of [Mo(CO)6] (264 mg,1.0 mmol) in CH3CN (20 mL)
was refluxed for 3 h under an argon atmosphere. The resulting
yellow solution was cooled down to room temperature and 1 equiv.
of ligand (505 mg, 1.0 mmol) in toluene (8 mL) was added and the
solution was refluxed for 4 days. After this period the solvent was
evaporated under vacuum and the compound was washed with
CH3CN and n-pentane. The compound was dried under vacuum
affording a yellow powder. Yield: 633 mg (92%). Anal. Calcd. for
C
34H29N3O3P2Mo (685.51): C, 59.57; H, 4.26; N, 6.13%. Found: C,
59.74; H, 4.19; N, 6.23%. 1H NMR ( , CD2Cl2, 20 ꢀC): 7.44e7.60 (m,
d
21H, Ph, py4), 6.34 (d, J ¼ 8.2 Hz, 2H, py3,5), 2.99 (s, 6H, NCH3). 13
C
{1H} NMR (
d
, CD2Cl2, 20 ꢀC): 227.8 (t, J ¼ 4.9 Hz), 211.9 (t, J ¼ 9.9 Hz),
161.0e161.1 (m, py2,6), 143.9 (s, py4), 136.3 (t, J ¼ 5.8 Hz, py2,6), 134.9
(d, J ¼ 45.5 Hz, Ph1), 131.8 (s, Ph4), 130.6 (t, J ¼ 5.2 Hz, Ph3,5), 130.5 (s,
Ph4), 129.0 (d, J ¼ 58.8 Hz, Ph1), 128.4 (t, J ¼ 4.9 Hz, Ph3,5), 127.9 (t,
J ¼ 5.4 Hz, Ph2,6), 100.0 (s, py3,5), 35.7 (s, NCH3). 31P{1H} NMR (
d,
CD2Cl2, 20 ꢀC): 143.0. IR (ATR, 25 ꢀC): 1956 (
nC]O), 1911 (nC]O),
1850 (nC]O). ESI-MS (m/z, CH3OH, NaCl) positive ion: 704.07
[M þ Na]þ.
4.3.3. [Mo(PNPMe-Ph)(CO)2I2] (3a)
Method A: A solution of 2 (200 mg, 0.292 mmol) in CH3CN
(10 mL) was cooled down to ꢁ78 ꢀC and 1 equiv. of I2 (74.1 mg,
0.292 mmol) was added. The solution was slowly warmed to room
temperature and stirred for 18 h. After this period the solution was
filtered, solvent was removed under vacuum, and the red solid was
washed twice with CH3CN and dried under vacuum. Method B: A
solution of [MoI2(CO)3(CH3CN)2] (200 mg, 0.883 mmol) in CH3CN
(10 mL) was treated with 1 equiv. of 1 (196.0 mg, 0.388 mmol). The
solution was stirred for 18 h and then filtrated. The product was
washed twice with CH3CN and n-pentane and then dried under
vacuum to yield a red powder. Yield: 217 mg (81%). Anal. Calcd. for
4.3. Syntheses
4.3.1. N,N0-bis(diphenylphosphino)-N,N0-methyl-2,6-
diaminopyridine (PNPMe-Ph) (1)
A
solution of 2,6-N,N0-dimethyldiaminopyridine (2.0 g,
14.58 mmol) in toluene (125 mL) was cooled down to ꢁ20 ꢀC and
n-BuLi (2.5 M solution in hexane, 6.10 mg, 15.31 mmol) was added.
The mixture was stirred at room temperature for 2 h. After this
period, the mixture was cooled down to ꢁ60 ꢀC and then PPh2Cl
(2.6 mL, 14.58 mmol) was added. The mixture was stirred for 2 h at
room temperature and then refluxed overnight at 80 ꢀC. The
mixture was allowed to cool down to room temperature and 8 mL
of a saturated solution of NaHCO3 was added. The two phases were
separated and anhydrous Na2SO4 was added to the organic phase.
The mixture was filtered and the solvent was evaporated leading
to a yellow oil. The oil was dissolved in 125 mL of toluene and
cooled down to ꢁ20 ꢀC and then n-BuLi (2.5 M solution in hexane,
6.10 mg, 15.31 mmol) was added. The mixture was stirred at room
temperature for 2 h. After this period, the mixture was cooled
down to ꢁ60 ꢀC and then again PPh2Cl (2.6 mL, 14.58 mmol) was
added. The mixture was stirred for 2 h at room temperature and
then refluxed overnight at 80 ꢀC. After this period a saturated so-
lution of NaHCO3 was added to the mixture at room temperature.
The two phases were separated and anhydrous Na2SO4 was added
to the organic phase. The mixture was filtered and the solvent was
removed under vacuum yielding a yellow oil together with a white
C
33H29I2N3O2P2Mo (911.31): C, 43.49; H, 3.21; N, 4.61%. Found: C,
43.30; H, 3.18; N, 4.73%. 1H NMR (
d
, CD2Cl2, 20 ꢀC): 7.86 (t, J ¼ 8.2 Hz,
1H, py4), 7.63 (t, J ¼ 8.2 Hz, 4H, Ph2,6), 7.52 (t, J ¼ 7.0 Hz, 2H, Ph4),
7.41 (t, J ¼ 6.9 Hz, 4H, Ph2,6), 7.07 (t, J ¼ 7.2 Hz, 2H, Ph4), 6.85 (t,
J ¼ 7.1 Hz, 4H, Ph3,5), 6.60 (t, J ¼ 7.3 Hz, 4H, Ph3,5), 6.36 (d, J ¼ 8.2 Hz,
2H, py3,5), 3.14 (s, 6H, NCH3). 13C{1H} NMR ( , CD2Cl2, 20 ꢀC): 162.1e
d
163.1 (m, py2,6), 144.8 (s, py4), 138.7 (t, J ¼ 5.7 Hz, py2,6), 132.6 (s,
Ph4),130.6 (t, J ¼ 5.7 Hz, Ph3,5), 130.5 (s, Ph4), 129.0 (t, J ¼ 4.9 Hz,
Ph3,5), 128.3 (t, J ¼ 5.5 Hz, Ph2,6), 100.3 (s, py3,5), 36.1 (s, NCH3). The
quaternary Ph and CO carbon atoms could not be detected. 13C
solid-state NMR (
NMR (
d
, 12 kHz, 25 ꢀC): 228.5 (CO), 218.2 (CO). 31P{1H}
C]O), 1870
d
, CD2Cl2, 20 ꢀC): 141.3. IR (ATR, 25 ꢀC): 1946 (
n
(nC]O). ESI-MS (m/z, CH3OH, NaI) positive ion: 901.88
[M þ Na ꢁ CO]þ, 751.99 [M ꢁ (CO þ NaI)]þ.
4.3.4. [Mo(PNPMe-Ph)(CO)2Br2] (3b)
Method A: This complex was prepared analogously to 3a
(method A) with 2 (200 mg, 0.292 mmol) and (Br2) (14.96
mL,
0.292 mmol) as starting materials. Method B: This complex was
prepared analogously to 3a (method B) with [MoBr2(CO)3(CH3CN)2]

S.R.M.M. de Aguiar et al. / Journal of Organometallic Chemistry 760 (2014) 74e83
81
(200 mg, 0.474 mmol) and 1 (239.6 mg, 0.474 mmol) as starting
materials. Method C: A solution of [Mo(CO)4( -Br)Br]2 (200 mg,
J ¼ 7.3 Hz, 2H, py3,5), 3.07 (s, 6H, NCH3).13C{1H} NMR (
d
, CD2Cl2,
m
20 ꢀC): 161.4e161.7 (m, py2,6), 144.3 (s, py4), 136.7 (t, J ¼ 5.9 Hz,
py2,6), 132.3 (s, Ph4), 131.12 (t, J ¼ 5.1 Hz, Ph3,5), 130.9 (s, Ph4), 128.9
(t, J ¼ 4.9 Hz, Ph3,5),128.4 (t, J ¼ 5.4 Hz, Ph2,6),100.5 (s, py3,5), 36.2 (s,
NCH3). The quaternary Ph and CO carbon atoms could not be
0.272 mmol) in CH3CN (10 mL) was treated with 1 equiv. of 1
(137.5 mg, 0.272 mmol) and the solution was stirred for 18 h. After
this period the solution was filtered, the solvent was removed
under reduced pressure, and the remaining yellow solid was
washed twice with CH3CN and n-pentane. Yield: 186.5 mg (84%).
Anal. Calcd. for C33H29Br2N3O2P2Mo (817.31): C, 48.50; H, 3.58; N,
detected. 13C solid-state NMR (
(CO). 31P{1H} NMR (
C]O), 1974 ( C]O), 1862 (nC]O), 1846 (nC]O). ESI-MS (m/z,
d
, 12 kHz, 25 ꢀC): 257.6 (CO), 215.1
d
, CD2Cl2, 20 ꢀC): 147.2. IR (ATR, 25 ꢀC): 2000
(
n
n
5.14%. Found: C, 48.42; H, 3.63; N, 5.06%. 1H NMR (
d
, CD2Cl2, 20 ꢀC):
CH3OH, NaCl) positive ion: 718.01 [M þ Na ꢁ CO]þ, 660.05
7.84 (t, J ¼ 7.8 Hz, 1H, py4), 7.63 (t, J ¼ 7.4 Hz, 4H, Ph2,6), 7.53 (t,
J ¼ 7.2 Hz, 2H, Ph4), 7.44 (t, J ¼ 7.1 Hz, 4H, Ph2,6), 7.16 (t, J ¼ 7.2 Hz,
2H, Ph4), 6.93 (t, J ¼ 7.2 Hz, 4H, Ph3,5), 6.64 (t, J ¼ 8.0 Hz, 4H, Ph3,5),
[M ꢁ (CO þ NaCl)]þ.
4.3.6. [Mo(PNPMe-Ph)(CO)2F2] (3d)
6.39 (d, J ¼ 8.0 Hz, 2H, py3,5), 3.11 (s, 6H, NCH3). 13C{1H} NMR (
d,
To a solution of 2 (200 mg, 0.292 mmol) of CH2Cl2 (10 mL) 1
equiv. of 1-fluoro-2,4,6-trimethylpyridinium tetrafluoroborate
(66.28 mg, 0.292 mmol) was added. The solution was stirred for 3
days. After this period the solution was filtered, the solvent was
then removed under vacuum, and the remaining orange solid was
washed with twice with CH2Cl2 and dried under vacuum. Yield:
189 mg (93%). Anal. Calcd. for C33H29F2N3O2P2Mo (695.50): C,
56.99; H, 4.20; N, 6.04%. Found: C, 57.15; H, 4.26; N, 6.11%. 1H NMR
CD2Cl2, 20 ꢀC): 161.4e161.6 (m, py2,6), 144.6 (s, py4), 137.6 (t,
J ¼ 6.0 Hz, py2,6), 135.8 (d, J ¼ 45.9 Hz, Ph1), 132.2 (s, Ph4), 130.3 (t,
J ¼ 4.9 Hz, Ph3,5), 130.2 (s, Ph4), 129.3 (d, J ¼ 56.2 Hz, Ph1), 128.5 (t,
J ¼ 4.8 Hz, Ph3,5), 128.2 (t, J ¼ 5.5 Hz, Ph2,6), 100.1 (s, py3,5), 35.9 (s,
NCH3). The quaternary CO carbon atoms could not be detected. 13
C
solid-state NMR (
d
, 12 kHz, 25 ꢀC): 244.8 (CO), 225.7 (CO). 31P{1H}
C]O), 1858
NMR (
d
, CD2Cl2, 20 ꢀC): 145.2. IR (ATR, 25 ꢀC): 1979 (
n
(
d
, CD3CN, 20 ꢀC): 7.98 (t, J ¼ 8.1 Hz, 1H, py4), 7.58 (dd, J ¼ 14.2,
(nC]O). ESI-MS (m/z, CH3OH, NaBr) positive ion: 805.91
[M þ Na ꢁ CO]þ, 704.00 [M ꢁ (CO þ NaBr)]þ.
6.9 Hz, 4H, Ph2,6), 7.11e7.49 (m, 8H, Ph4, Ph2,6), 7.01 (t, J ¼ 7.2 Hz, 4H,
Ph3,5), 6.66 (d, J ¼ 8.3 Hz, 2H, py3,5), 6.37 (dd, J ¼ 10.8, 7.7 Hz, 4H,
Ph3,5), 2.54 (s, 6H, NCH3). 31P{1H} NMR ( , CD3CN, 20 ꢀC): 155.7 (t,
d
4.3.5. [Mo(PNPMe-Ph)(CO)2Cl2] (3c)
This complex was prepared analogously to 3b (Method C) with
[Mo(CO)4(m-Cl)Cl]2 (200 mg, 0.359 mmol) and 1 (181.3 mg,
2JPF ¼ 41.7 Hz). 13C solid-state NMR (
d
, 12 kHz, 25 ꢀC): 250.4 (CO),
214.3 (CO). IR (ATR, 25 C): 1977 (nC]O), 1880 (nC]O). ESI-MS (m/z,
CH3OH, NaF) positive ion: 644.08 [M ꢁ (CO þ NaF)]þ.
0.359 mmol) as starting materials. Yield: 211.7 mg (81%). Anal.
Calcd. for C33H29Cl2N3O2P2Mo (728.41): C, 54.22; H, 4.01; N, 5.77%.
Found: C, 54.10; H, 3.91; N, 5.81%. 1H NMR (
d
, CD2Cl2, 20 ꢀC): 7.83 (t,
4.4. X-ray structure determinations
J ¼ 7.6 Hz, 1H, py4), 7.67 (t, J ¼ 8.9 Hz, 4H, Ph2,6), 7.54 (t, J ¼ 7.4 Hz,
2H, Ph4), 7.45 (t, J ¼ 6.9 Hz, 4H, Ph2,6), 7.24 (t, J ¼ 7.3 Hz, 2H, Ph4),
7.00 (t, J ¼ 7.3 Hz, 4H, Ph3,5), 6.69 (t, J ¼ 7.6 Hz, 4H, ph3,5), 6.40 (d,
Single crystals for X-ray diffraction were obtained as follows:
[Mo(PNPMe-Ph)(CO)3]$CH2Cl2 (2$CH2Cl2) by slow diffusion of n-
Table 2
Details for the crystal structure determinations of the solvates 2$CH2Cl2, 3a$CD2Cl2, 3b$3CDCl3, and 3c$1.5CD2Cl2.
2$CH2Cl2
3a$CD2Cl2
3b$3CDCl3
3c$1.5CD2Cl2
Formula
Fw
C35H31Cl2MoN3O3P2
770.4
C34H29Cl2D2I2MoN3O2P2
998.3
C36H29Br2Cl9D3MoN3O2P2
653.23
C34.5H29Cl5D3MoN3O2P2
858.80
Cryst. size, mm
Color, shape
Crystal system
Space group
0.71 ꢂ 0.34 ꢂ 0.05
0.64 ꢂ 0.62 ꢂ 0.46
Orange block
Monoclinic
0.54 ꢂ 0.22 ꢂ 0.03
0.72 ꢂ 0.35 ꢂ 0.30
Yellow block
Triclinic
Yellow rod
Yellow rod
Monoclinic
P21/n (no. 14)
Monoclinic
P21/c (no. 14)
P21/c (no. 14)
P 1
(no. 2)
a, Å
b, Å
c, Å
9.7002(5)
23.0768(11)
15.6657(7)
90
100.1630(9)
90
9.4602(8)
17.8964(16)
21.2970(19)
90
90.001(2)
90
16.1514(9)
11.1407(6)
25.4476(12)
90
104.289(2)
90
10.9919(15)
11.9429(16)
15.499(2)
111.189(3)
95.185(3)
105.903(3)
1783.3(4)
100
a
, deg
, deg
b
g
, deg
V, Å3
3451.7(3)
100
3605.7(5)
100
4437.3(4)
100
T, K
Z
4
4
4
2
rcalc, g cmꢁ3
1.4821
0.667
1.8383
2.349
1.7634
2.748
1.5989
0.869
m
, mmꢁ1 (Mo-K
a
)
F(000)
Absorption corrections, Tmin ꢁ Tmax
range, deg
No. of rflns measd
Rint
1568
1936
2320
866
Multi-scan,0.76e0.98
2.20e30.01
27,241
0.0167
10,026
8629
Multi-scan, 0.24e0.34
2.15e32.54
31,658
0.0185
12,333
11,346
415/0
0.0254
0.0288
0.0343
0.0355
1.87
Multi-scan, 0.49e0.92
1.30e27.54
77,590
0.0983
10,223
6237
509/0
0.0378
0.0908
0.0339
0.0365
1.15
ꢁ0.96/0.88
Multi-scan, 0.70e0.77
1.89e32.68
62,193
0.0543
13,007
11,319
442/0
0.0323
0.0393
0.0453
0.0462
1.79
ꢁ0.97, 0.95
q
No. of rflns unique
No. of rflns I > 3
No. of params/restraints
R1 (I > 3
(I))a
R1 (all data)
wR2 (I > 3 (I))
s
(I)
432/0
s
0.0259
0.0328
0.0314
0.0333
1.86
s
wR2 (all data)
GooF
Diff. four. peaks min/max, eÅꢁ3
ꢁ0.51/0.62
ꢁ1.35/1.60
P
P
P
P
P
a
R1
¼
kFoj: ꢁ j:Fck= jFoj; wR2 ¼ f ½wðFo2 ꢁ Fc2Þ2ꢃ= ½wðFo2Þ2ꢃg1=2
;
GooF ¼
f
½wðFo2 ꢁ Fc2Þ2ꢃ=ðn ꢁ pÞg1=2
.

82
S.R.M.M. de Aguiar et al. / Journal of Organometallic Chemistry 760 (2014) 74e83
(1995) 127e131;
pentane into a CH2Cl2 solution, [Mo(PNPMe-Ph)(CO)2l2]$CD2Cl2
(3a$CD2Cl2) and [Mo(PNPMe-Ph)(CO)2Br2]$3CDCl3 (3b$3CDCl3)
and [Mo(PNPMe-Ph)(CO)2Cl2]$1.5CD2Cl2 (3c$1.5CD2Cl2) by slow
evaporation of CD2Cl2 and CDCl3 solutions, respectively. The color
of the crystals varied from yellow to orange. X-ray diffraction data
were collected at T ¼ 100 K in a dry stream of nitrogen on Bruker
Smart APEX CCD (3a$CD2Cl2) and Bruker Kappa APEX-2 CCD
(3b$3CDCl3 and 3c$1.5CD2Cl2) diffractometer systems using
(c) M.D. Curtis, K. Shiu, Inorg. Chem. 24 (1985) 1213;
(d) C.L. Schwarz, R.M. Bullock, C. Creutz, J. Am. Chem. Soc. 113 (1991) 1225;
(e) P. Chaudhuri, K. Wieghardt, Y.H. Tsai, C. Krüger, Inorg. Chem. 23 (1984)
427.
[5] L.A. Wingard, P.S. White, J.L. Templeton, Dalton Trans. 41 (2012) 11438.
[6] S.J.N. Burgmayer, J.L. Templeton, Inorg. Chem. 24 (1985) 2224.
[7] A.M. Bond, R. Colton, D.G. Humphrey, V. Tedesco, A. van den Bergen, Organ-
ometallics 17 (1998) 3908.
[8] M.A. Alvarez, G. Garcia, M. Esther Garcia, V. Riera, M.A. Ruiz, M. Lanfranchi,
A. Tiripicchio, Organometallics 18 (1999) 4509.
[9] R.G. Parr, W. Yang, Density Functional Theory of Atoms and Molecules, Oxford
University Press, New York, 1989.
graphite-monochromatised Mo-K
fine sliced 4- and -scans (3a$CD2Cl2: only
a
radiation (
l
¼ 0.71073 Å) and
u
u-scans) covering
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(b) Wiberg indices are electronic parameters related to the electron density
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Calculations were performed using the Gaussian 09 software
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structure and bonding of the optimized species. The NPA analysis
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referred along the text were calculated with the same functional
and a 6-311þþG(d,p) basis set [30], using the geometries obtained
at the PBE0/b1 level.
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ꢀ ꢀ
ꢀ
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J.A. Montgomery Jr., J.E. Peralta, F. Ogliaro, 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. Stratmann, 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,
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CT, USA, 2009.
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Acknowledgment
Financial support by the Austrian Science Fund (FWF) (Project
No. P24202-N17) and by Fundação para a Ciência e Tecnologia, FCT
(PEst-OE/QUI/UI0100/2013) is gratefully acknowledged.
Appendix A. Supplementary material
Supplementary material related to this article can be found at
http://dx.doi.org/10.1016/j.jorganchem.2013.12.018.
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