Two Triazole-Based Phosphine Ligands Prepared via Temperature-Mediated Li/H Exchange: CuI and AuI Complexes and Structural Studies

Article abstract of DOI:10.1021/acs.inorgchem.6b01094

The kinetically favored triazole-based phosphine 1-(2-(diphenylphosphino)phenyl)-4-phenyl-1H-1,2,3-triazole (2, L₁) and its thermodynamically preferred isomer, 5-(diphenylphosphino)-1,4-diphenyl-1H-1,2,3-triazole (3, L₂), were obtained by the temperature-controlled lithiation of 2-bromotriazole followed by the reaction with chlorodiphenylphosphine. The structures of phosphines 2 and 3 were determined by X-ray diffraction. Upon reaction with late transition-metal derivatives (Cu^I, Ag^I, and Au^I), phosphines 2 and 3 form complexes with monodentate (Cu^I, Ag^I, and Au^I κ¹-P), chelate (Cu^I κ²-P,N), bridged bidentate (Cu^I μ²-P,N), and tridentate (Cu^I μ²,κ²-P,N,N) modes of coordination. Reactions with copper(I) halides produced mono-, di-, and tetranuclear complexes, whereas the reaction of 2 with [Cu(NCCH₃)₄]BF₄ yielded the binuclear complex [Cu₂(CH₃CN)₂{o-Ph₂P(C₆H₄){1,2,3-N₃C(Ph)C(H)}-μ-(κ-P,κ-N),κ-N}₂](BF₄)₂ (10) with the ligand acting as a six-electron donor involving phosphorus and two triazole nitrogen atoms. The copper complexes of 2 and 3 containing rhomboid Cu₂X₂ units, [(Cu)₂(μ-X)₂{o-Ph₂P(C₆H₄){1,2,3-N₃C(Ph)C(H)}-κ-P}₂] (4, X = Cl; 5, X = Br), on treatment with 1,10-phenanthroline and 2,2′-bipyridine gave mixed-ligand complexes of the type [(CuX)(N∩N-κ²-N,N){o-Ph₂P(C₆H₄){1,2,3-N₃C(Ph)C(H)}-κ-P}] (N∩N = 1,10-phen and 2,2′-bipy; X = Cl, Br, and I).

Full text of DOI:10.1021/acs.inorgchem.6b01094

Article
pubs.acs.org/IC
Two Triazole-Based Phosphine Ligands Prepared via Temperature-
Mediated Li/H Exchange: CuI and AuI Complexes and Structural
Studies
Bimba Choubey,† Latchupatula Radhakrishna,† Joel T. Mague,‡ and Maravanji S. Balakrishna*,†
†Phosphorus Laboratory, Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
‡Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
S
* Supporting Information
ABSTRACT: The kinetically favored triazole-based phosphine 1-
(2-(diphenylphosphino)phenyl)-4-phenyl-1H-1,2,3-triazole (2,
L1) and its thermodynamically preferred isomer, 5-(diphenyl-
phosphino)-1,4-diphenyl-1H-1,2,3-triazole (3, L2), were obtained
by the temperature-controlled lithiation of 2-bromotriazole
followed by the reaction with chlorodiphenylphosphine. The
structures of phosphines 2 and 3 were determined by X-ray
diffraction. Upon reaction with late transition-metal derivatives
(CuI, AgI, and AuI), phosphines 2 and 3 form complexes with
monodentate (CuI, AgI, and AuI; κ1-P), chelate (CuI; κ2-P,N),
bridged bidentate (CuI; μ2-P,N), and tridentate (CuI; μ2,κ2-P,N,N)
modes of coordination. Reactions with copper(I) halides
produced mono-, di-, and tetranuclear complexes, whereas the reaction of 2 with [Cu(NCCH3)4]BF4 yielded the binuclear
complex [Cu2(CH3CN)2{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-μ-(κ-P,κ-N),κ-N}2](BF4)2 (10) with the ligand acting as a six-
electron donor involving phosphorus and two triazole nitrogen atoms. The copper complexes of 2 and 3 containing rhomboid
Cu2X2 units, [(Cu)2(μ-X)2{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ-P}2] (4, X = Cl; 5, X = Br), on treatment with 1,10-
phenanthroline and 2,2′-bipyridine gave mixed-ligand complexes of the type [(CuX)(N∩N-κ2-N,N){o-Ph2P(C6H4){1,2,3-
N3C(Ph)C(H)}-κ-P}] (N∩N = 1,10-phen and 2,2′-bipy; X = Cl, Br, and I).
the positions of phosphorus moieties, 1-(2-(diphenyl-
phosphino)phenyl)-4-phenyl-1H-1,2,3-triazole (2) and 5-
(diphenylphosphino)-1,4-diphenyl-1H-1,2,3-triazole19 (3), by
temperature-mediated Li/H exchange reaction of 2-bromo-
phenyl triazole (1). Also, copper(I) and gold(I) complexes of
these two new ligands and the X-ray structures of several
complexes including the ligands are described herein.
INTRODUCTION
■
The design and synthesis of triazole-based ligand systems have
drawn considerable attention in the last few decades owing to
their novelty in organometallic chemistry and catalytic
applications.1−4 The copper-catalyzed version of the Huisgen
1,3-dipolar cycloaddition reaction reported by Sharpless and
Meldal is a versatile click reaction for coupling azides with
alkynes.5−7 This is also a convenient method to incorporate
triazole functionalities into phosphine systems or vice versa.
Although triazole itself is a good ligand,8,9 it is anticipated that
incorporating phosphine moieties on the ring atoms or into the
exocyclic groups would give interesting ambidentate properties,
which can be exploited in catalytic reactions. For example,
triazole-based phosphines such as ClickPhos [Ph{1,2,3-N3C-
(PPh2)C(Ph)}],10,11 ClicFerrophos [1-PPh2Fc-2−CH(Me)-
{1,2,3-N3C(PPh2)C(Ph)}],12,13 ClickPhine [Ph{1,2,3-N3C-
(CH2PPh2)C(Ph)}],14 and bisphosphines of the type
[R2PCH2{1,2,3-N3C(CH2PR2)C(H)}] (R = Ph, Cy, tBu,
iPr)15,16 have been employed in various catalytic reactions. As
an extension of our interest17 and the interest of others18 to get
more insight into the triazole-based phosphines, we sought to
examine the compatibility of triazoles with phosphorus
moieties. This paper describes a very simple and efficient
synthetic route to prepare two structural isomers differing in
RESULTS AND DISCUSSION
■
Synthesis of 1-(2-(Diphenylphosphino)phenyl)-4-
phenyl-1H-1,2,3-triazole (2) and 5-(Diphenylphosphi-
no)-1,4-diphenyl-1H-1,2,3-triazole (3). The reaction of 2-
bromophenyl azide with phenylacetylene in the presence of
copper sulfate and sodium ascorbate under Sharpless
conditions yielded 1-(2-bromophenyl)-4-phenyl-1H-1,2,3-tria-
zole [o-Br(C6H4)-1,2,3-N3] (1) as a white crystalline solid in
1
good yield. The H NMR spectrum of 1 showed a singlet at
8.17 ppm corresponding to the triazolic proton. The reaction of
n
1 with BuLi at −78 °C followed by the addition of 1 equiv of
PPh2Cl at −78 °C resulted in the formation of the kinetically
stable phosphine derivative, [o-Ph2PC6H4{1,2,3-N3C(Ph)C-
Received: May 4, 2016
© XXXX American Chemical Society
A
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(H)}] (2). However, the successive treatment of 2-
positions of 1. Recently, Baumann and co-workers reported20
the one-pot synthesis of a structural isomer of 3, namely, 4-
(diphenylphosphino)-1,5-diphenyl-1H-1,2,3-triazole, and its di-,
tri-, and tetrameric copper complexes. The 31P{1H} NMR
spectra of 2 and 3 consist of single resonances at −15.5 and
−30.2 ppm, respectively. The 1H NMR spectrum of 2 showed a
sharp singlet at 7.73 ppm for the triazolic proton, whereas the
same was not observed in the case of 3.
n
bromophenyl-triazole with BuLi at −78 °C and 1 equiv of
PPh2Cl at room temperature yielded 5-(diphenylphosphino)-
1,4-diphenyl-1H-1,2,3-triazole, [C6H5{1,2,3-N3C(Ph)C-
(PPh2)}] (3) as a white crystalline solid as shown in Scheme
n
1. The lithiation of 2-bromophenyl-triazole using BuLi gave
Scheme 1. Probable Pathways for the Formation of
Phosphines 2 and 3
To gain some insight into the nature of isomerization
process, variable-temperature (VT) 7Li and 31P NMR studies of
I in diethyl ether (external locking) and phosphine 2 (in
deuterated dimethyl sulfoxide (DMSO-d6)) were performed.
The dynamic NMR investigation revealed the initial formation
of lithiated product I at low temperature showing a singlet
7
(δ Li) at 1.87 ppm. When the solution was warmed, a second
singlet started appearing at 1.23 ppm, the intensity of which
gradually increased, whereas the intensity of the former
decreased proportionately, and at 25 °C it vanished completely
(Figure 1) indicating the complete isomerization of product I
into product II. The VT 31P NMR of phosphine 2 in DMSO-d6
did not show any isomerization leading to the formation of
31P
phosphine 3. The singlet (δ −15.5) observed at room
temperature did not change even at 100 °C ruling out any
possibility of isomerization of 2 to 3 (see Supporting
Information Figure S38). Similar results were obtained in the
VT cross polarization magic-angle spinning 31P NMR of
phosphines 2 and 3 as well. Density functional theory
calculations also supported these observations (Figure 2).
The initially formed lithiated product I at low temperature is a
kinetically favored high-energy species, which, when warmed,
isomerizes to thermodynamically favored low-energy species II.
Both the phosphines 2 and 3 were characterized by single-
crystal X-ray analysis (see Figures 3). Single crystals of 2 were
obtained from diethyl ether solution at 0 °C, and those of 3
were obtained from an ethanol solution of 3 stored at 0 °C for
24 h.
the kinetically favored intermediate I at low temperature,
whereas the same reaction at room temperature resulted in the
formation of thermodynamically more stable intermediate II.
Subsequent reactions of I and II with chlorodiphenylphosphine
produced new triazole-based phosphines 2 and 3. The reaction
n
of phenyltriazole [C6H4{1,2,3-N3C(Ph)CH}] with BuLi at
−78 °C followed by the addition of chlorodiphenylphosphine
also resulted in the formation 3 in 75% yield. The temperature-
controlled lithiation of 2-bromophenyl-triazole (1) provides a
novel methodology for the synthesis of very useful products by
considering different electrophiles at the phenylic and triazolic
The asymmetric unit consists of two molecules of 2 with
different orientations. In one molecule, the pyramidal geometry
around the phosphorus atom (C1−P1−C7 = 104.45(11)°,
7
Figure 1. Time-dependent Li NMR spectra for the reaction of 1 with n-butyl lithium in diethyl ether at 25 °C.
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1,2,3-triazole 2 and its structural isomer 3 are potential
tridentate ligands, and it would be interesting to explore their
coordination behavior with various transition-metal precursors,
in particular, with group 11 metals due to their remarkable
ability to adopt a variety of structural motifs and also to accept
soft to not-so-soft donor atoms. The possible coordinating
modes for the ligands 2 and 3 are depicted in Chart 1. Although
simple κ1-coordination via phosphorus atom is the most
common and preferred mode for both the ligands 2 and 3,
ligand 2 with proper orientation of the triazole side arm can
show chelating (II) as well as chelating-cum-bridging (III)
modes to perform as a tridentate ligand, which is so far not
observed with triazole-based derivatives. Other possible
coordinating modes (IV, VI, and VII) depicted in Chart 1 are
less likely; however, they are not ruled out, as appropriate metal
precursors and certain orientations of the triazole arm might
facilitate these coordination modes as well.
Figure 2. Lithium−hydrogen exchange transition state. Relative ΔG
(in kcal/mol) and bond lengths (in Å).
Reaction between CuX (X = Cl, Br, and I) and [o-
Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}] (2) in 1:1 ratio produced
binuclear complexes [(Cu)2(μ-X)2{o-Ph2P(C6H4){1,2,3-N3C-
(Ph)C(H)}-κ-P}2] (4, X = Cl; 5, X = Br; 6, X = I) and the
tetranuclear octahedron-type complex [(Cu)4(μ-I)4{o-Ph2P-
(C6H4){1,2,3-N3C(Ph)C(H)}-μ(κ-P,κ-N)}2] (6a) as shown
in Scheme 2. Recently, a similar type of tetranuclear complex
containing aminobis(phosphonite) ligands has been reported.22
The 31P NMR spectra of complexes 4−6 show single
resonances at −7.4, −8.3, and −10.9 ppm, respectively. The
1H NMR spectra of 4−6 consists of singlets at 8.93, 8.66, and
8.63 ppm corresponding to the triazolic protons.
Treatment of complexes 4−6 with 1,10-phenanthroline in
1:1 molar ratio afforded mixed ligand complexes [(CuX)(1,10-
phen-κ2-N,N){o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ-P}] (X
= 7, Cl; 8, X = Br; 9, X = I) as bright orange crystalline
solids in good yield (Scheme 2). Complexes 7−9 are partially
soluble in acetonitrile and dimethyl sulfoxide. The 31P NMR
spectra of complexes 7−9 show single peaks at −6.9, −6.4, and
−5.0 ppm, respectively. The 1H NMR spectra of these
complexes show single broad resonances in the range of
8.85−8.91 ppm for the triazolic proton. The structure of 7
(Figure 4) was confirmed by single-crystal X-ray analysis.
The asymmetric unit consists of one molecule of 7 and two
molecules of dichloromethane as solvent of crystallization. The
copper atom displays distorted tetrahedral geometry with
internal angles in the range of 79.98(13)−136.77(9)°. The
Cu1−P1 and Cu1−Cl1 bond distances are 2.1923(11) and
C1−P1−C13 = 99.55(10)°, C7−P1−C13 = 101.43(10)°) is
significantly more distorted than that of the second molecule
(C39−P2−C27 = 102.15(10)°, C33−P2−C27 = 102.28(11)°,
C33−P2−C39 = 102.15(10)°). However, the P−C bond
distances are nearly the same in both the molecules; that is,
P1−C13 = 1.850(2) Å, and P2−C39 = 1.845(2) Å. The two
phenyl rings on the phosphorus atoms are almost orthogonal to
each other as can be seen from their torsion angles (P1−C1−
C6−C5 = 177.77(9)°, P1−C7−C8−C9 = −176.76(18)°, P2−
C27−C28−C29 = −179.6(2)°, and P2−C33−C38−C37 =
176.8(18)°). The triazole ring is nearly planar with an N4−
N5−N6 bond angle of 107.1(2)°. The interesting aspect in the
molecular structure of 2 is the presence of intra- and
intermolecular hydrogen bonding. In the case of phosphine 3,
one of the phenyl rings on the phosphorus atom is
perpendicular to the central triazole ring, whereas the other
phenyl ring shows a weak intramolecular aromatic π−π
interaction with the phenyl group bonded to the nitrogen
atom of the triazole moiety. The π−π interaction has an
interplanar distance of 3.596 Å, which lies within the range of
π−π interactions (3.58−4.29 Å) reported in the literature.21 As
a consequence, the P1−C15 [1.8223(17) Å] bond distance is
elongated when compared to P1−C21 [1.8204(17) Å]. The
C7−P1−C15 bond angle is 102.31(7)°, whereas the C7−P1−
C21 angle is found to be 103.21(7)°.
Copper(I) and Gold(I) Complexes. The newly prepared
phosphine, 1-(2-(diphenylphosphino)phenyl)-4-phenyl-1H-
Figure 3. Molecular structures of 2 and 3. All hydrogen atoms were omitted for clarity.
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Chart 1. Possible Coordination Modes for Phosphines 2 and 3
Scheme 2. Copper(I) Complexes of 2
1
2.2871(10) Å, respectively. The triazole ring nitrogens are
disposed away from the copper center, whereas the center
triazolic carbon is closer to copper atom giving a stable
configuration. The Cu−N distances (Cu1−N2 = 2.062(3) and
Cu1−N1 = 2.142(3) Å) are comparable to the same observed
in similar complexes reported in the literature.23
The reaction of 2 with 1 equiv of [Cu(CH3CN)4]BF4 in
acetonitrile yielded a binuclear complex [Cu2(CH3CN)2{o-
Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-μ-(κ-P,κ-N),κ-N }2](BF4)2
(10) with the ligand exhibiting chelating as well as bridging
modes of coordination as shown in Scheme 2. The 31P NMR
spectrum of 10 shows singlet at −9.1 ppm. The H NMR
spectrum consists of a sharp singlet at 2.06 ppm for
coordinated acetonitrile and at 8.20 ppm for the triazolic
protons. Complex 10 on recrystallization gave water-coordi-
nated complex [Cu2(CH3CN)(H2O){o-Ph2P(C6H4){1,2,3-
N3C(Ph)C(H)}-μ-(κ-P,κ-N),κ-N}2](BF4)2 (10a) due to the
presence of adventitious water, where one of the coordinated
acetonitriles was replaced by a water molecule. The IR
spectrum of 10 showed υCN at 2282 cm−1, which is shifted to
a higher wavenumber relative to free acetonitrile (2250 cm−1)
indicating an increased NC bond strength because of metal
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unit. Both the metal ions are tetrahedrally ligated by one
phosphorus atom and two nitrogen atoms of each ligand and
the fourth site by a solvent molecule. The N6−Cu1−O1
(95.33(9)°), O1−Cu1−P1 (127.99(7)°), O1−Cu1−N2
(105.60(9)°), P1−Cu1−N6 (130.28(7)°), and N2−Cu1−N6
(105.44(8)°) bond angles obviously indicate the distortion in
the tetrahedral geometry, which is true for the second copper
center also. The bite angles P1−Cu1−N2 (87.00(6)°) and P2−
Cu2−N5 (89.65(6)°) are slightly different from each other.
Both the copper atoms and bridging ligands are in a twisted
boat conformation. The torsion angles Cu2−N5−N6−Cu1
(45.79°) and Cu2−N3−N2−Cu1 (50.85°) indicate that both
the copper centers are slightly twisted from planarity. The
Cu1−N2 and Cu2−N5 distances are 2.304(2) and 2.224(2) Å,
respectively, which are quite different, whereas the Cu1−N6
(2.017(2) Å) and Cu2−N3 (2.017(2) Å) distances are the
same. The Cu1−O1 and Cu2−N7 bond distances are 2.059(2)
and 1.991(3) Å, respectively. The orientation of the triazole
rings are slightly displaced from both the copper planes. The
nonbonding Cu1···Cu2 distance is 3.667 Å. Weak hydrogen
bonding, specifically, O1−H1A···F8 (2.957(5) Å, 161.6°), O1−
H1B···F2 (2.788(3) Å, 148.6°), C2−H2···F2 (3.553(4) Å,
162.4°), C17−H17···F6 (3.285(4) Å, 153.1°), C43−H43···
F5(3.199(4) Å, 147.6°), and C55−H55A···F7 (3.271(4) Å,
132.3°) were also observed. This is the first example of a
crystallographically characterized cationic dicopper complex
containing a triazolic phosphine acting as a tridentate ligand.
The structure is similar to the recently reported silver complex
of a pyridine-appended triazole, [Ag(NO3){(C5H5N)CH2-
{1,2,3-N3C(Ph)}-κ-N,κ-N,κ-N}]2.9
Figure 4. Molecular structure of 7. All hydrogen atoms were omitted
for clarity.
coordination.24 The molecular structure of 10a (Figure 5) was
confirmed by single-crystal X-ray analysis.
Copper Derivatives of [C6H5{1,2,3-N3C(Ph)C(PPh2)}]
(3). The reaction of 3 with 1 equiv of CuX (X = Cl, Br, and
I) in acetonitrile yielded binuclear tricoordinated complexes
[Cu(μ-X)2Cu{C6H5{1,2,3-N3C(Ph)C(PPh2)}-κ-P}2] (11, X =
Cl; 12, X = Br; 13, X = I) with the ligand showing the
monodentate coordination mode. Complexes 11−13 are
colorless, air-stable solids and soluble in most organic solvents.
Figure 5. Molecular structure of 10a. All hydrogen atoms were
omitted for clarity.
The molecular structure reveals that the two copper centers
are bridged by two molecules of ligand 2 forming a dimeric
Figure 6. Molecular structure of 13. All hydrogen atoms were omitted for clarity.
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Figure 7. Molecular structures of 14, 15, and 17. All hydrogen atoms were omitted for clarity.
Figure 8. Molecular structures of 20 and 21. All hydrogen atoms were omitted for clarity.
The molecular structure of complex 13 (Figure 6) consists of
Cu2I2 cores with each of the copper(I) centers being
tricoordinated by one phosphorus atom and two bridging
iodides. The molecule has crystallographically imposed
centrosymmetry with two triazole moieties adopting the anti-
conformation with respect to the copper centers. The [PCu(μ-
I)2CuP] unit is almost planar. Several trigonal planar binuclear
copper complexes of this type containing monophosphines
have been well-characterized.20 The Cu2−P3 bond length
(2.2328(9) Å) in complex 13 is comparable with that in
[(Cu)2(μ-I)2{(C6H5){1,2,3-N3C(PPh2)C(Ph)}}2]24 (Cu−P =
2.2118(9) Å). The Cu···Cu distance of 2.568 Å indicates the
possible metal−metal interaction between the two copper
atoms having some positive or attractive interaction between
the closed-shell d10 metal ions.25 The Cu2−I1−Cu2, I1−Cu2−
I1_a, I1−Cu2−P3, C26−P3−Cu2, and N4−N36−N18 bond
angles are 59.41(1)°, 120.59(2)°, 124.24(2)°, 110.96(9)°, and
108.1(2)°, respectively. These angles obviously indicate a
distortion of the copper coordination sphere.
The complexes 14, 15, and 17 (Figure 7) are isostructural. In
these complexes the copper atoms are in a distorted tetrahedral
geometry. The Cu−P distances are 2.2000(11), 2.1979(5), and
2.1874(5) Å for 14, 15, and 17, respectively. There is π−π
stacking in the case of 14 between 1,10-phenanthroline ring of
two independent molecules with an interplanar distance of
3.337(5) Å. In complexes 14 and 15 the Cu1−N9, Cu1−N23,
Cu1−N1, and Cu1−N2 distances are 2.147(3), 2.079(3),
2.0715(15), and 2.1403(14) Å, respectively. Considerable
difference was observed between the two Cu−N atom distances
The 31P NMR spectra of 11−13 show broad single
resonances at −19.2, −23.3, and −28.1 ppm, respectively,
which are considerably deshielded compared to that of the free
ligand. The compositions and molecular structures of 11−13
were confirmed by microanalytical, 1H NMR, and mass spectral
data. The structure of 13 was confirmed by X-ray analysis.
Because of the presence of halo-bridged rhombic Cu2X2
units, the dimeric complexes 11−13 readily react with 2,2′-
bipyridine and 1,10-phenanthroline to give monomeric
complexes [(CuX)(1,10-phen-κ2-N,N){C6H5{1,2,3-N3C(Ph)C-
(PPh2)}-κ-P}] (14, X = Cl; 15, X = Br; 16, X = I) and
[(CuX)(2,2′-bipy-κ2-N,N){C6H5{1,2,3-N3C(Ph)C(PPh2)}-κ-
P}] (17, X = Cl; 18, X = Br; 19, X = I) as bright orange or
yellow crystalline compounds. These complexes are moderately
stable toward air and soluble in acetonitrile, dichloromethane,
and dimethyl sulfoxide. The 31P NMR spectra of complexes
14−19 show single resonances in the range from −16.7 to
1
−24.3 ppm. The compositions of 14−19 were verified by H
NMR, mass spectrometry, microanalysis, and, in the cases of
13−15 and 17, by single-crystal X-ray analysis.
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Table 1. Crystallographic Information for Compounds 2, 3, 7, and 10a
2
3
7
10a
formula
FW
C26H20N3P
C26H20N3P
4−5.40
C40H32Cl5CuN5P
854.46
C55H47B2Cl2Cu2F8N7OP2
1255.53
405.42
crystal system
space group
a, Å
triclinic
monoclinic
triclinic
triclinic
P1
̅
P21/c
P1
̅
P1
̅
7.4106(4)
15.1870(7)
19.4567(9)
72.029(1)
87.871(1)
86.280(1)
2078.19(18)
4
13.2112(14)
11.1621(9)
14.5906(14)
90
10.1064(5)
13.1454(7)
15.2293(8)
100.385(3)
107.129(2)
90.703(3)
1897.23(17)
2
10.2654(7)
12.6027(9)
22.9535(16)
100.6880(10)
92.7270(11)
107.2020(10)
2277.8(3)
2
b, Å
c, Å
α, deg
β, deg
108.833(11)
90
γ, deg
V, Å3
2036.4(4)
4
Z
ρcalc g cm−3
μ(Mo Kα)
F(000)
crystal size, mm
T, (K)
1.296
1.299
1.496
1.505
0.150
0.153
4.747
0.996
848
848
872
1276
0.10 × 0.12 × 0.16
150(2)
02.x02 × 0.16
100
0.040 × 0.160 × 0.160
102(2)
0.050 × 0.080 × 0.230
150(2)
2θ range, deg
total reflns
No. of indep reflns
R
1.1−28.3
17837
2.42−31.384
12861
3.09−68.41
44874
1.78−28.71
25873
13 685 [Rint = 0.0359]
0.0534
3580 [Rint = 0.0720]
0.0411
6748 [R(int) = 0.0583]
0.0546
13 923 [R(int) = 0.0423]
0.0514
wR2
0.1463
0.1060
0.1472
0.1278
S
1.03
1.036
1.100
1.106
Table 2. Crystallographic Information for Compounds 13−15, 17, 20, and 21
13
14
15
17
20
21
formula
FW
C26H20CuIN3P
595.86
C38H28ClCuN5P
684.61
C28H28BrCuN5P
608.97
C36H28ClCuN5P
660.59
C26H20AuClN3P
637.84
C26H20AuClN3P
637.84
crystal system
space group
a, Å
monoclinic
P21/c
triclinic
triclinic
triclinic
triclinic
triclinic
P1
̅
P1
̅
P1
̅
P1
̅
P1
̅
9.842(3)
14.101(4)
16.584(6)
90
10.053(3)
10.133(3)
15.978(5)
82.510(12)
74.233(9)
81.596(11)
1542.5(8)
2
10.1081(10)
10.2599(10)
16.0076(15)
82.7180(13)
73.6460(13)
81.9780(13)
1570.7(3)
2
10.6311(5)
11.0562(5)
14.9648(7)
110.0360(6)
90.8080(7)
114.1740(7)
1482.92(12)
2
9.5590(5)
9.9126(7)
13.4010(7)
99.547(2)
95.713(2)
112.4390(10)
1138.79(12)
2
10.3148(5)
10.3840(5)
11.6306(6)
78.009(2)
75.910(2)
76.813(2)
1161.02(10)
2
b, Å
c, Å
α, deg
β, deg
γ, deg
V, Å3
95.314(7)
90
2291.7(12)
4
Z
ρcalc (g cm−3
)
1.727
1.474
1.288
1.479
1.860
1.825
μ(Mo Kα), mm−1 2.390
0.884
2.041
0.917
6.666
6.539
F(000)
1176
704
620
680
616
616
crystal size, mm
T, (K)
0.20 × 0.20 × 0.20 0.26 × 0.10 × 0.26 0.140 × 0.240 × 0.260 0.080 × 0.120 × 0.190 0.050 × 0.160 × 0.180 0.150 × 0.160 × 0.170
100
100
150(2)
150(2)
150(2)
150(2)
2θ range, deg
2.9−25.0
3.10−25.0
11 628
2.01−29.17
28 849
2.12−29.24
27 361
1.57−32.03
48 372
1.83−33.14
41 604
total no. of reflns 16 534
no. of indep. reflns 3965 [Rint = 0.0302] 5296 [Rint = 0.0499] 8084 [Rint = 0.0326]
7662 [R(int) =
0.0419]
7887 [Rint = 0.0423]
8767 [Rint = 0.0411]
R
0.0232
0.0412
0.0293
0.0363
0.0182
0.0247
wR2, S
0.0557, 1.080
0.1073, 1.01
0.0760, 1.04
0.0874, 1.030
0.0454, 1.068
0.0581, 1.055
of the 1,10-phenanthroline, whereas in complex 17, the
differences between the Cu−N bonds [Cu1−N1= 2.0879(15)
Å, Cu1−N2 = 2.0678(16) Å] is marginal (0.0201 Å).
appeared as a singlet at 8.18 ppm. The electrospray ionization
(ESI) mass spectrum of 20 showed a peak at 660.07 [M + Na]+
as the base peak. The high-resolution mass spectrometry
(HRMS) data for 21 consist of a molecular ion peak at m/z
638.0803 [M + H]+. The molecular structures of 20 and 21
(Figure 8) were determined by single-crystal X-ray diffraction
studies.
In complex 20, two adjacent molecules are arranged in an
anti-parallel manner, and hence there is no intermolecular
gold−gold interaction, as the Au···Au separations are 5.017 and
The gold complexes [AuCl{o-Ph2P(C6H4){1,2,3-N3C(Ph)-
C(H)}-κ-P}] (20) and [AuCl{C6H5{1,2,3-N3C(Ph)C(PPh2)}-
κ-P}] (21) were obtained by reacting ligands 2 and 3 with
AuCl(SMe2) in 1:1 molar ratios in dichloromethane at room
temperature. The 31P NMR spectra of 20 and 21 consist of
1
singlets at 27.8 and 12.3 ppm, respectively. In the H NMR
spectrum of 20, the peak corresponding to the triazolic proton
G
DOI: 10.1021/acs.inorgchem.6b01094
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Table 3. Selected Bond Distances (Å) and Bond Angles (deg) for Compounds 2 and 3
bond distances (Å)
bond angles (deg)
bond distances (Å)
compound 3
bond angles (deg)
compound 2
P2−C39
1.845(2)
1.831(2)
1.829(2)
1.350(3)
1.314(3)
1.349(3)
1.372(3)
1.365(3)
1.437(3)
1.407(3)
C39−P2−C33
102.15(10)
102.28(11)
121.1(2)
P1−C7
P1−C21
N3−N2
N3−C8
N2−N1
C8−C9
C8−C7
C7−N1
C1−N1
1.8146(17)
1.8204(17)
1.303(2)
1.356(2)
1.354(2)
1.448(2)
1.373(2)
1.372(2)
1.447(2)
C7−P1−C21
103.21(7)
P2−C33
P2−C27
N4−N5
C33−P2−C27
C39−C44−N4
C44−N4−N5
N4−N5−N6
N4−C45−C46
C46−N6−N5
P2−C39−C44
C33−P2−C39
C44−C39−C40
C7−P1−C15
N2−N3−C8
N3−N2−N1
N3−C8−C9
N3−C8−C7
C8−C7−P1
N2−N1−C1
C7−N1−C1
102.31(7)
108.24(13)
108.27(14)
120.78(14)
110.05(14)
123.54(13)
118.77(14)
131.03(14)
121.33(17)
107.1(2)
N5−N6
N4−C45
C45−C46
C46−N6
N4−C44
C39−C44
105.35(19)
109.4(2)
122.55(17)
102.15(10)
116.0(2)
5.511 Å.26 The Au−Cl (2.2912(5) Å) and Au−P (2.2334(4) Å)
bond lengths are comparable to those in (PhO)3PAuCl (Au−
Cl = 2.273(5) Å, Au−P = 2.192(5) Å).27 The geometry around
gold is almost linear with Cl−Au−P bond angle of
175.891(16)°, which is similar to the same found in
(PhO)3PAuCl (Cl−Au−P = 178.5(2)°). The two phenyl
rings on phosphorus centers are perpendicular to each other
with torsion angles P1−C1−C2−C3 (179.94(16)°) and P1−
C7−C12−C11 (−176.44(14)°). The triazole ring nitrogens are
away from the P1−C13−C18−N1 (−2.4(2)°) plane with the
torsion angle C18−N1−N2−N3 being −179.57(16)°. In
complex 20, the Au−Cl (2.2912(5) Å) and Au−P (2.2334(4)
Å) bond distances are similar to those found in (PhO)3PAuCl
(Au−Cl = 2.273(5) Å, Au−P = 2.192(5) Å).27 The Cl−Au−P
bond angle of 175.891(16)° is slightly less than that found in
[Ph3PAuCl]28 (Cl−Au−P = 179.63°).
EXPERIMENTAL SECTION
■
General Procedures. All manipulations were performed using
standard vacuum-line and Schlenk techniques under a nitrogen
atmosphere. All the solvents were purified by conventional procedures
and distilled prior to use. The compounds CuX (X = Cl, Br),29
[Cu(CH3CN)4]BF4,30 AuCl(SMe2),31 and 2-bromophenylazide32
were prepared according to the published procedures. Other chemicals
were obtained from commercial sources and purified prior to use.
Instrumental Methods. The NMR spectra were recorded at the
following frequencies: 400 MHz (1H), 100 MHz (13C), and 162 MHz
(31P) (δ in ppm) using either Varian VXR 400, Bruker AV 400, or
Bruker AV 500 spectrometers. The spectra were recorded in CDCl3
(or DMSO-d6)) solutions with CDCl3 (or DMSO-d6) as an internal
lock; tetramethylsilane and 85% H3PO4 were used as external
1
standards for H and 31P{1H} NMR, respectively. Positive shifts lie
downfield to the standard in all of the cases. Infrared spectra were
recorded on a Nicolet Impact 400 FTIR instrument in KBr disk or
mineral oil mull. The microanalyses were performed using a Carlo
Erba Model 1112 and flash EA 1112 series elemental analyzer. Mass
spectra were recorded using Waters Q-TOF micro (YA-105), maXis
impact, and 410 Prostar Binary LC. The melting points of all
compounds were determined on a Veego melting point apparatus and
are uncorrected. Low-temperature experiments were performed using
a Julabo model FT 902.
Synthesis of 2-Bromophenyltriazole [o-Br(C6H4){1,2,3-N3C(Ph)C-
(H)}] (1). 2-Bromophenylazide (1.97 g, 10.3 mmol) and phenyl-
acetylene (0.930 g, 9.1 mmol) were suspended in a 1:1 mixture of
water and tertiary butyl alcohol. Sodium ascorbate (3.6 mmol, freshly
prepared solution in water) was added followed by CuSO4·5H2O (1.6
mmol, freshly prepared solution in water), and the reaction mixture
was stirred for 24 h at room temperature. The product obtained was
extracted with diethyl ether. The combined ether extracts were dried
over anhydrous Na2SO4, filtered, and concentrated under reduced
pressure to give a yellow crystalline solid. Yield: 86% (2.4 g). mp 97−
99 °C. HRMS (ESI): m/z Calcd for C14H10N3Br ([M + H]+):
300.0136, 302.0116; found: 300.0161, 302.0081. IR: 1587, 1497, 1479
cm−1. 13C NMR (CDCl3): δ 118.5, 120.4, 125.8, 128.1, 128.4, 128.5,
CONCLUSIONS
■
Two new triazole-based phosphines have been reported. At low
temperature, a kinetically controlled reaction prevails, whereas
at room temperature (25 °C), the chemical equilibrium can
assert itself via Li/H exchange, which leads to the isolation of
thermodynamically more stable isomer. We anticipate that
these kinetically versus thermodynamically controlled inter-
mediates can act as potential synthons to generate useful
organic products by using different electrophiles. Both the
phosphines show interesting coordination properties. The
phosphine with an exocyclic triazole (2) shows κ-P, κ2-P,N-
chelation as well as μ-(κ-N,κ-N)-bridging coordination modes
to act as mono-, di-, or tridentate ligand. Tridentate
coordination is rarely seen among triazole-based ligands.
Reaction of 2 with [Cu(NCCH3)4][BF4]2 yielded a dicopper
complex with ligand exhibiting rare tridentate mode of
coordination. Phosphine with an endocyclic triazole (3) prefers
monodentate (κ-P) coordination mode, although it can show
bridging (μ-(κ-N,κ-P)) coordination mode; but with bulky arms
on both the sides, it can be a very valuable ligand to stabilize the
low-valent platinum metals. By choosing appropriate metal
reagents and reaction conditions, both mono and chelating
bidentate modes of coordination were achieved. It is anticipated
that the synthetic flexibility found in the present system would
be of enormous assistance in ever-growing field of click
chelates, especially in connection with their potential catalytic
and biological activities. Further metal chemistry and catalytic
reactions with these systems are under active investigation in
our laboratory.
1
128.9, 129.7, 130.1, 131.2, 133.9, 136.5. H NMR (CDCl3): δ 7.26−
7.49 (m, Ph, 5H), 7.50−7.94 (m, PhBr, 4H) 8.17 (s, CH, 1H). Anal.
Calcd for C14H10N3Br: C, 56.02; H, 3.35; N, 13.99. Found: C, 56.36;
H, 3.23; N, 13.73%.
Synthesis of [o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}] (2). To a Schlenk
flask charged with 2-bromophenyltriazole 1 (2.11 g, 7.02 mmol) in
diethyl ether (70 mL) was added dropwise a hexane solution of nBuLi
(4.83 mL, 7.73 mmol, 1.6 M solution in hexane) at −78 °C, and the
mixture was stirred for 8 h at −78 °C. A solution of PPh2Cl (1.55 g,
1.28 mL, 7.02 mmol) in diethyl either (15 mL) was added into the
mixture at −78 °C, followed by warming to room temperature, and
stirring was continued for a further period of 9 h. The solution was
filtered through a diatomaceous earth bed to remove LiCl. The dark
yellow solution was concentrated under reduced pressure, and the
residue obtained was washed with 4 × 4 mL of petroleum ether and
dissolved in 30 mL of diethyl ether and stored at −15 °C to give 2 as
H
DOI: 10.1021/acs.inorgchem.6b01094
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
I
DOI: 10.1021/acs.inorgchem.6b01094
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
Table 6. Selected Bond Distances (Å) and Bond Angles (deg) for Compounds 20 and 21
bond distances (Å)
bond angles (deg)
bond distances (Å)
bond angles (deg)
compound 20
compound 21
Au1−P1
Au1−Cl1
P1−C1
2.2334(4)
2.2912(5)
1.8067(17)
1.8101(17)
1.8304(17)
1.352(2)
C13−P1−Au1
114.27(5)
Au1−P1
2.2294(6)
2.2811(6)
1.801(2)
1.803(2)
1.832(3)
1.344(3)
1.370(3)
1.438(3)
1.313(3)
1.362(3)
P1−Au1−Cl1
179.23(3)
P1−Au1−Cl1
N3−N2−N1
C19−N1−N2
N2−N1−C18
N2−N3−C20
C2−C1−P1
C1−C2−C3
C6−C1−P1
C2−C1−C6
175.891(16)
107.09(14)
110.64(15)
119.22 (14)
109.31(15)
119.44(13)
119.64(18)
120.85(13)
119.69(16)
Au1−Cl1
P1−C13
P1−C1
C13−P1−C7
C13−P1−Au1
C7−P1−Au1
N2−N1−C21
N3−N2−N1
C1−P1−C7
C1−P1−Au1
N2−N1−C13
C13−P1−C1
105.13(10)
111.64(7)
111.93(8)
119.81(18)
107.43(18)
105.14(14)
114.91(8)
111.10(18)
107.40(10)
P1−C7
P1−C13
N1−C19
N1−N2
N1−C18
N3−C20
N2−N3
P1−C7
N1−N2
N1−C13
N1−C21
N2−N3
N3−C14
1.353(2)
1.438(2)
1.363(2)
1.313(2)
analytically pure colorless needles. Yield: 61.7% (1.76 g). mp 137−139
°C. IR: 2412, 1964, 1879, 1807, 1642, 1476, 1445 cm−1. 13C NMR
(CDCl3): δ 122.4, 126.0, 126.8, 128.4, 128.9, 129.5, 130.0, 130.2,
132.3, 134.1, 134.3, 134.7, 134.8, 135.5, 141.1, 147.3. 1H NMR
(CDCl3): δ 7.05−7.76 (m, ArH, 19H), 7.73 (s, triazolicH, 1H).
31P{1H} NMR (CDCl3): δ −15.5 ppm (s). HRMS (ESI): m/z Calcd
for NaC26H20N3P ([M + Na]+): 428.1292; Found: 428.1286. Anal.
Calcd for C26H20N3P: C, 77.01; H, 4.97; N, 10.36; Found: C, 76.90;
H, 4.89; N, 10.08%.
Synthesis of [(Cu)2(μ-Br)2{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ-P}2]
(5). Compound 5 was synthesized by a procedure similar to 4 using
CuBr (0.0070 g, 0.0493 mmol) and 2 (0.020 g, 0.0493 mmol). The
analytically pure product 5 was obtained as a colorless powder. Yield:
1
68% (0.037g). mp: 154 °C. H NMR (DMSO-d6): δ 7.09−8.03 (m,
Ar, 38H) 8.66 (br, s, triazolicH, 2H). 31P{1H} NMR (DMSO-d6): δ
−8.3 (s) ppm. HRMS (ESI): m/z Calcd for C52H40Cu2N6P2Br2 ([M-
Br]+): 1015.056; Found: 1017.0544. Anal. Calcd for
C52H40Br2Cu2N6P2: C, 56.87; H, 3.67; N, 7.66. Found: C, 56.75; H,
3.47; N, 7.87%.
Synthesis of [C6H5{1,2,3-N3C(Ph)C(PPh2)}] (3). (Method A). To a
Schlenk flask charged with 2-bromophenyltriazole (1) (2.2 g, 7.3
mmol) in diethyl ether (70 mL) at −78 °C was added dropwise a
Synthesis of [Cu2(μ-I)2{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ-P}2] (6).
Compound 6 was synthesized by a procedure similar to 5 using CuI
(0.0188 g, 0.0986 mmol) and 2 (0.040 g, 0.0986 mmol). The
analytically pure product 6 was obtained as a pale yellow powder.
n
hexane solution of BuLi (5.01 mL, 8.03 mmol, 1.6 M solution in
hexane). The mixture was allowed to warm to room temperature and
was stirred for 5 h. Again the solution was cooled to −78 °C, and
PPh2Cl (1.61 g, 1.33 mL, 7.3 mmol) was added dropwise through a
cannula. The resulting mixture was slowly warmed to room
temperature and stirred for 9 h, and LiCl was filtered off. The solvent
was removed under reduced pressure, and the yellow oily residue
obtained was washed with petroleum ether, dissolved in minimum
amount ethanol, and stored at −15 °C to get analytically pure product
of 3 as white crystalline solid. Yield: 62% (1.8 g).
1
Yield: 81% (0.048 g). mp 246 °C (dec). H NMR (DMSO-d6): δ
7.30−7.7 (m, Ar, 38H), 8.87 (s, triazolicH, 2H). 31P{1H} NMR
(DMSO-d6): δ −10.75 (s) ppm. HRMS (ESI): m/z Calcd for
C52H40Cu2I2N6P2 ([M-I]+): 1065.0410; Found: 1063.0421. Anal.
Calcd for C52H40Cu2I2N6P2: C, 52.40; H, 3.38; N, 7.05. Found: C,
52.65; H, 3.47; N, 7.41%.
Synthesis of [Cu4(μ-I)4{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ2-P,N}2]
(6a). Compound 6a was synthesized by a procedure similar to 5 using
CuI (0.0093 g, 0.0493 mmol) and 2 (0.020 g, 0.0493 mmol). The
analytically pure product 6 was obtained as a pale yellow powder.
Yield: 71% (0.055 g). mp 256−258 °C. 1H NMR (DMSO-d6): δ
7.10−7.98 (m, Ar, 38H), 8.63 (s, triazolicH, 2H). 31P{1H} NMR
(DMSO-d6): δ −10.9 (s) ppm. Anal. Calcd for C52H40Cu4I4N6P2·
CH2Cl2: C, 38.40; H, 2.56; N, 5.07. Found: C, 38.96; H, 2.01; N,
5.03%.
Method B. To a solution of 1,4-diphenyl-1H-1,2,3-triazole33 (1 g,
4.52 mmol) in diethyl ether (30 mL) at −78 °C nBuLi (3.1 mL, 1.6 M
in hexane, 4.972 mmol) was added dropwise over 15 min. The
reaction mixture was allowed to attain room temperature and was
stirred for 6 h. The reaction mixture was cooled to −78 °C, and a
solution of PPh2Cl (0.997 g, 4.52 mmol) in diethyl ether (10 mL) was
added dropwise over 20 min. The resulting mixture was stirred for 9 h
at room temperature and then filtered through diatomaceous earth to
remove LiCl. All the volatiles were removed under reduced pressure,
and the residue was purified by column chromatography on silica gel
(petroleum ether/EtOAc, 95:5) to obtain compound 1 as a white solid
(1.37 g, 75%).
Synthesis of [(CuCl)(1,10-phen-κ2-N,N){o-Ph2P(C6H4){N3C(Ph)C-
(H)}-κ-P}] (7). A solution of 2 (0.020 g, 0.049 mmol) in CH3CN (5
mL) was added dropwise to a solution of CuCl (0.0049 g, 0.049
mmol) dissolved in CH3CN (3 mL), and the mixture was stirred for
10 h at room temperature. Then 1,10-phenanthroline (0.0073 g,
0.0493 mmol) in CH3CN (5 mL) was added, and the solution was
stirred for a further period of 1 h. The solvent was removed under
vacuum; the residue was washed with petroleum ether and dried in
vacuo to give analytically pure product of 7 as orange solid. The X-ray
quality crystals were obtained by recrystallizing it from a mixture of
CH2Cl2/petroleum ether at room temperature. Yield: 83% (0.028g).
mp 152−154 °C. IR: 2342, 1964, 1876, 1596, 1498, 1468, 1434
cm−1. 13C NMR (CDCl3): δ 120.4, 125.8, 126.3, 127.9, 128.5, 128.8,
1
129.0, 129.4, 129.7, 130.7, 132.3, 132.3, 132.5, 132.6, 137.2, 154.3. H
NMR (CDCl3): δ 7.14−7.52 (m, ArH, 20H). 31P{1H} NMR (CDCl3):
δ −30.2(s) ppm. HRMS (ESI): m/z Calcd for C26H21N3P ([M +
H]+): 406.1473; Found: 406.1478. Anal. Calcd for C26H20N3P: C,
77.02; H, 4.97; N, 10.36. Found: C, 76.64; H, 4.83; N, 9.91%.
Synthesis of [Cu2(μ-Cl)2{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ-P}2]
(4). A solution of 2 (0.020 g, 0.049 mmol) in CH3CN (5 mL) was
added dropwise to a solution of CuCl (0.0049 g, 0.049 mmol) in
CH3CN (3 mL), and the mixture was stirred for 20 h at room
temperature. The solvent was removed under vacuum, washed with 4
× 3 mL of petroleum ether, and dried in vacuo to give analytically pure
product of 4 as a white solid. Yield: 72% (0.036 g). mp 147−149 °C
1
mp 138 °C (dec). H NMR (CDCl3): δ 7.26−8.63 (m, ArH, 27H),
8.91 (br, s, triazolicH, 1H), 5.5 (CH2Cl2). 31P{1H} NMR (CDCl3): δ
−6.9 (s) ppm. Anal. Calcd For C38H28ClCuN5P·CH2Cl2: C, 60.85; H,
3.95; N, 9.10. Found: C, 60.63; H, 4.36; N, 9.17%.
Synthesis of [CuBr(1,10-phen-κ2-N,N){o-Ph2P(C6H4){N3C(Ph)C(H)}-
κ-P}] (8). To a solution of 5 (0.054 g, 0.0493 mmol) in CH3CN (7
mL) was added dropwise 1,10-phenanthroline (0.0073 g, 0.0493
mmol) also in CH3CN (4 mL). The mixture was stirred for 3 h at
room temperature. The solvent was removed under vacuum; the
residue was washed with petroleum ether and dried under vacuo to
give analytically pure product of 8 as orange solid. Yield: 75% (0.027
g). mp 148−151 °C. 1H NMR (CDCl3): δ 7.23−8.61 (m, ArH, 27H),
8.85 (br, s, triazolicH, 1H). 31P{1H} NMR (CDCl3): δ −6.4 (s) ppm.
1
(dec). H NMR (CDCl3): δ 7.10−7.80 (m, Ar, 38H), 8.93 (br, s,
triazolicH, 2H). 31P{1H} NMR (CDCl3): δ −7.4(s) ppm. Anal. Calcd
for C52H40Cl2Cu2N6P2: C, 61.91; H, 4.00; N, 8.33. Found: C, 62.23;
H, 3.60; N, 8.23%.
J
DOI: 10.1021/acs.inorgchem.6b01094
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HRMS (ESI): m/z Calcd for C38H28CuN5PBr ([M-Br]+): 648.1373;
Found: 648.1374. Anal. Calcd for C38H28BrCuN5P: C, 62.59; H, 3.87;
N, 9.60. Found: C, 62.83; H, 3.57; N, 9.29%.
crystals of 14. Yield: 68% (0.017 g). mp 239−241 °C (dec). 1H NMR
(CDCl3): δ 6.84−7.54 (m, Ar, 28 H). 31P{1H} NMR (CDCl3): δ
−23.8 ppm. Anal. Calcd for C38H28N5PCuCl: C, 66.66; H, 4.12; N,
10.23. Found: C, 66.41; H, 3.83; N, 9.81%.
Synthesis of [CuI(1,10-phen-κ2-N,N){o-Ph2P(C6H4){1,2,3-N3C(Ph)-
C(H)}-κ-P}] (9). To a solution of 6 (0.077 g, 0.0493 mmol) in CH3CN
(7 mL) was added 1,10-phenanthroline (0.0073 g, 0.0493 mmol). The
mixture was stirred for 3 h at room temperature. The solvent was
removed under vacuum, and the residue was washed with petroleum
ether and dried in vacuo to give analytically pure product of 9 as an
orange solid. Yield: 74% (0.028 g). mp 243 °C (dec). 1H NMR
(DMSO-d6): δ 7.12−8.06 (m, Ar, 27H), 8.90 (br, s, triazolicH, 1H).
31P{1H} NMR (DMSO-d6): −5.00 (s) ppm. HRMS (ESI): m/z Calcd
Synthesis of [CuBr(1,10-phen-κ2-N,N){C6H5{1,2,3-N3C(Ph)C-
(PPh2)}-κ-P}2] (15). To a solution of 12 (0.0405 g, 0.037 mmol) in
acetonitrile (10 mL) was added 1,10 phenanthroline (0.0073 g, 0.037
mmol) in the same solvent. The reaction mixture was stirred at room
temperature for 2 h. The resulting orange solution was concentrated
and kept at room temperature to give bright orange, X-ray quality
crystals of 15. Yield: 85% (0.023 g). mp 223−225 °C (dec). 1H NMR
(CDCl3): δ 6.77−7.52 (m, ArH, 28H). 31P{1H} NMR (CDCl3): δ
−22.4 ppm. HRMS (ES): m/z Calcd for C38H28N5PCu ([M-Br]+):
648.1378; found: 648.14. Anal. Calcd for C38H28N5PCuBr: C, 62.60;
H, 3.87; N, 9.61. Found: C, 62.31; H, 3.50; N, 9.53%.
for C38H28CuN5PI ([M-I]+): 648.1373; Found: 648.1376. Anal. Calcd
for C38H28ICuN5P: C, 58.81; H, 3.64; N, 9.02. Found: C, 58.55; H,
3.47; N, 8.66%.
Synthesis of [CuI(1,10-phen-κ2-N,N){C6H5{1,2,3-N3C(Ph)C(PPh2)}-
κ-P}] (16). A solution of 3 (0.0168 g, 0.041 mmol) in CH3CN (5 mL)
was added dropwise to a solution of CuI (0.0079 g, 0.041 mmol)
dissolved in CH3CN (3 mL), and the mixture was stirred for 6 h at
room temperature. Then 1,10-phenanthroline (0.0082 g, 0.041 mmol)
was added to the same solution, and stirring was continued for 2 h.
The solvent was removed under vacuum, and the residue was washed
with petroleum ether and dried in vacuo to give analytically pure
product of 16 as a bright orange solid. Yield: 84% (0.027 g). mp 218−
220 °C. 1H NMR (CDCl3): δ 6.78−8.75 (m, Ar, 28H). 31P{1H} NMR
(CDCl3): δ −16.7 ppm. Anal. Calcd for C38H28N5PCuI: C, 58.81; H,
3.64; N, 9.02. Found: C, 58.78; H, 3.33; N, 8.80%.
Synthesis of [Cu2(CH3CN)2{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ3-
P,N,N}2](BF4)2 (10). A solution of 2 (0.015 g, 0.037 mmol) in
CH3CN (5 mL) was added dropwise to a solution of [{Cu-
(CH3CN)4}BF4] (0.0116 g, 0.037 mmol) dissolved in CH3CN (3
mL), and the mixture was stirred for 20 h at room temperature. The
solvent was removed under reduced pressure, and the residue was
washed with 4 × 3 mL of petroleum ether and dried in vacuo to give
analytically pure product of 10 as a white solid. X-ray quality crystals
(10a) were obtained by recrystallizing it from a mixture of CH2Cl2/
petroleum ether, where one coordinated acetonitrile molecule was
replaced by one water molecule. Yield: 65% (0.0286 g). mp 153−155
°C. IR(υCN) (KBr disk): 2282(s), 1485 (vs), 1435 (vs), 1360(s),
1310(s), 1282(m), 1222(s), 1185(w), 1068(w), 907(s), 840(w) cm−1.
1H NMR (CDCl3): δ 2.06 (s, CH3CN, 6H), 6.81−7.83 (m, Ar, 38H),
Synthesis of [CuCl(2,2′-bipy-κ2-N,N){C6H5{1,2,3-N3C(Ph)C(PPh2)}-
κ-P}] (17). To a solution of 11 (0.0373 g, 0.037 mmol) in acetonitrile
(10 mL), was added 2,2′-bipyridine (0.0058 g, 0.037 mmol) in the
same solvent. The reaction mixture was stirred at room temperature
for 2 h. The resulting yellow solution was concentrated and kept at
room temperature to give pure, bright yellow, X- ray quality crystals.
8.20 (s, triazolicH, 2H). 31P{1H} NMR (CDCl3): δ −9.1 (s) ppm.
Anal. Calcd for C56H46N8P2Cu2B2F8: C, 56.35; H, 3.88; N, 9.39.
Found: C, 56.75; H, 3.55; N, 9.23%. Anal. Calcd for
C54H43N7P2Cu2OB2F8·CH2Cl2 (10a): C, 52.70; H, 3.62; N, 7.82.
Found: C, 52.62; H, 3.43; N, 8.22%.
1
Yield: 75% (0.018 g). mp 197 °C (dec). H NMR (CDCl3): δ 6.96−
7.48 (m, Ar, 28H). 31P{1H} NMR (CDCl3): δ −24.3 (s) ppm. Anal.
Calcd for C36H28N5PCuCl: C, 65.45; H, 4.27; N, 10.60. Found: C,
65.23; H, 3.96; N, 10.39.
Synthesis of [Cu2(μ-Cl)2{C6H5{1,2,3-N3C(Ph)C(PPh2)}-κ-P}2] (11).
To a solution of 3 (0.030 g, 0.074 mmol) in CH3CN (8 mL) was
added CuCl (0.0073 g, 0.074 mmol) dissolved in CH3CN (2 mL).
The mixture was stirred for 6 h at room temperature. The solvent was
removed under reduced pressure to afford the product as a colorless
Synthesis of [CuBr(2,2′-bipy-κ2−N,N){C6H5{1,2,3-N3C(Ph)C(PPh2)}-
κ-P}] (18). To a solution of 12 (0.0405 g, 0.037 mmol) in acetonitrile
(10 mL) was added 2,2′-bipyridine (0.0058 g, 0.037 mmol) in the
same solvent. The reaction mixture was stirred at room temperature
for 2 h. The solvent was removed under reduced pressure to afford the
product as a bright yellow colored compound. Yield: 73% (0.019 g).
1
solid. Yield: 74% (0.055 g). mp 156−158 °C. H NMR (CDCl3): δ
6.90−7.57 (m, ArH, 40H). 31P{1H} NMR (CDCl3): δ −19.2 ppm (s,
br). Anal. Calcd for C52H40N6P2Cu2Cl2: C, 61.89; H, 3.99; N, 8.33.
Found: C, 61.53; H, 3.54; N, 8.48%.
1
mp 215 °C (dec). H NMR (DMSO-d6): δ 7.00−7.38 (m, Ar, 28H).
Synthesis of [Cu2(μ-Br)2{C6H5{1,2,3-N3C(Ph)C(PPh2)}-κ-P}2] (12).
To a solution of 3 (0.030 g, 0.074 mmol) in CH3CN (8 mL) was
added CuBr (0.0106 g, 0.074 mmol) dissolved in CH3CN (2 mL), and
the mixture was stirred for 6 h at room temperature. The solvent was
removed under reduced pressure, and the residue was washed with
petroleum ether to afford the product as a colorless solid. Yield: 71%
(0.058 g). mp 138−141 °C. 1H NMR (CDCl3): δ 7.00−7.57 (m, ArH,
40H). 31P{1H} NMR (CDCl3): δ −23.3 (s) ppm. Anal. Calcd for
C52H40N6P2Cu2Br2: C, 56.89; H, 3.67; N, 7.65. Found: C, 57.13; H,
3.60; N, 7.46%.
31P{1H} NMR (DMSO-d6): δ −22.7 ppm. HRMS (ESI): m/z Calcd
for C36H28CuN5P ([M-Br]+): 624.1370; found: 624.1373. Anal. Calcd
for C36H28N5PCuBr: C, 61.33; H, 4.00; N, 9.93. Found: C, 61.21; H,
3.75; N, 9.83%.
Synthesis of [CuI(2,2′-bipy-κ2-N,N){C6H5{1,2,3-N3C(Ph)C(PPh2)}-κ-
P}] (19). A solution of 3 (0.030 g, 0.074 mmol) in CH3CN (5 mL) was
added dropwise to a solution of CuI (0.014 g, 0.074 mmol) dissolved
in CH3CN (3 mL), and the mixture was stirred for 4 h at room
temperature. Then 2,2′-bipyridine (0.0115 g, 0.074 mmol) was added
in the same solvent, and stirring was continued for 2 h. The solvent
was removed under vacuum, and the residue was washed with
petroleum ether and dried in vacuo to give analytically pure product of
19 as a bright yellow solid. Yield: 81% (0.045 g). mp 213-216 °C
Synthesis of [Cu2(μ-I)2{C6H5{1,2,3-N3C(Ph)C(PPh2)}-κ-P}2] (13). To
a solution of 3 (0.030 g, 0.074 mmol) in 5 mL CH3CN was added CuI
(0.0141 g, 0.074 mmol) dissolved in CH3CN (3 mL). The mixture
was stirred for 6 h at room temperature. The solvent was removed
under reduced pressure, and the residue was washed with petroleum
ether to afford the product as a colorless solid. The X-ray quality
crystals were obtained by recrystallizing it from a mixture of CH2Cl2/
petroleum ether at room temperature. Yield: 68% (0.060 g). mp > 230
1
(dec). H NMR (DMSO-d6): δ 7.03−7.55 (m, Ar, 28H). 31P{1H}
NMR (DMSO-d6): δ −24.2 (s). Anal. Calcd for C36H28N5PCuI: C,
57.49; H, 3.75; N, 9.31. Found: C, 57.60; H, 3.45; N, 9.16%.
Synthesis of [AuCl{o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-κ-P}] (20). A
solution of 2 (0.0150 g, 0.037 mmol) in CH2Cl2 (5 mL) was added in
AuCl(SMe2) (0.0105 g, 0.037 mmol) dissolved in CH2Cl2 (3 mL).
The mixture was stirred for 15 h at room temperature. The solvent was
removed under vacuum; the residue was washed with petroleum ether
and dried in vacuo to give analytically pure product 20 as a colorless
powder. The X-ray quality crystals were obtained by recrystallizing it
from a mixture of CH2Cl2/petroleum ether at room temperature.
1
°C. H NMR (CDCl3): δ 6.96−7.56 (m, Ar, 40H). 31P{1H} NMR
(CDCl3): δ −28.1 (s) ppm. Anal. Calcd for C52H40N6P2Cu2I2: C,
52.41; H, 3.38; N, 7.05. Found: C, 52.65; H, 3.16; N, 6.83%.
Synthesis of [CuCl(1,10-phen-κ2-N,N){C6H5{1,2,3-N3C(Ph)C-
(PPh2)}-κ-P}] (14). To a solution of 11 (0.0373 g, 0.037 mmol) in
acetonitrile (10 mL), was added 1,10 phenantroline (0.0073 g, 0.037
mmol) in the same solvent. The reaction mixture was stirred at room
temperature for 2 h. The resulting orange solution was concentrated
and kept at room temperature to give bright orange, X-ray quality
1
Yield: 85% (0.020 g). mp 130−132 °C. H NMR (CDCl3): δ 7.21−
7.81 (m, Ar, 19H), 8.18 (s, triazolicH, 1H). 31P{1H} NMR (CDCl3): δ
K
DOI: 10.1021/acs.inorgchem.6b01094
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
Article
27.8 (s) ppm. HRMS (ESI): m/z Calcd for C26H20N3PAuCl ([M +
Na]+): 660.0646; Found: 660.0656. Anal. Calcd for C26H20N3PAuCl:
C, 48.95; H, 3.16; N, 6.59. Found: C, 48.83; H, 3.04; N, 6.50%.
Synthesis of [AuCl{C6H5{1,2,3-N3C(Ph)C(PPh2)}-κ-P}] (21). To a
solution of 3 (0.030 g, 0.074 mmol) in CH2Cl2 (5 mL) was added
AuCl(SMe2) (0.0218 g, 0.074 mmol) also in CH2Cl2 (5 mL), and the
mixture was stirred for 4 h at room temperature. The solvent was
removed under reduced pressure to afford the product as a colorless
compound. The X-ray quality crystals were obtained by recrystallizing
it from a mixture of CH2Cl2/petroleum ether at room temperature.
Yield: 68% (0.032 g). mp > 230 °C (dec). 1H NMR (CDCl3): δ 7.06−
7.55 (m, Ar, 20H). 31P{1H} NMR (CDCl3): δ 12.3 (s) ppm. HRMS
(ESI): m/z Calcd for C26H21N3PAuCl ([M + H]+): 638.0827; Found:
638.0803. Anal. Calcd for C26H20N3PAuCl: C, 48.95; H, 3.16; N, 6.59.
Found: C, 48.89; H, 3.41; N, 6.79%.
X-ray Crystallography. A crystal of each of the compounds in the
present work suitable for X-ray crystal analysis was mounted on a
Cryoloop with a drop of mineral oil and placed in the cold nitrogen
stream on the Bruker APEX CCD or D8 Venture (for 9)
diffractometer. Full spheres of data were collected using a combination
of three sets of 606 scans in ω (0.3° per scan) at φ = 0°, 120°, and
240° or three sets of 400 frames, each of width 0.5° in ω, collected at φ
= 0.00°, 90.00°, and 180.00° and two sets of 800 frames, each of width
0.45° in φ, collected at ω = −30.00 and 210.00 (a hemisphere for 9)
under the control of the APEX2 program suite.34 The crystals of 2, 8a,
and 9 proved to be twinned (CELL_NOW).35 The raw data were
reduced to F2 values using the SAINT+ software,36 and a global
refinement of unit cell parameters using ca. 7662−9746 reflections
chosen from the full data sets was performed. In the case of the
twinned crystals, two-component reflection files were generated in this
step. Multiple measurements of equivalent reflections provided the
basis for an empirical absorption correction as well as a correction for
any crystal deterioration during the data collection (SADABS37 or
TWINABS38). All the crystal structures were solved by direct method
and refined by full-matrix least-squares procedures using the
SHELXTL program package.39,40 Hydrogen atoms attached to carbon
were placed in calculated positions and included as riding
contributions with isotropic displacement parameters tied to those
of the attached non-hydrogen atoms. In the case of 2, the full, two-
component reflection file was used for the final refinement, while for
8a and 9, superior refinement was achieved with the single-component
reflection file extracted from the twinned data by TWINABS. The
details of X-ray structural determinations are given in Tables 1 and 2,
and bond lengths and bond angles are given in Tables 3−6.
AUTHOR INFORMATION
Corresponding Author
*E-mail: krishna@chem.iitb.ac.in or msb_krishna@iitb.ac.in.
Fax: +91-22-5172-3480/2576-7152.
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We are grateful to the Department of Science and Technology
(DST), New Delhi, for financial support (SB/S1/IC-08/2014).
B.C. and L.R. thank UGC, New Delhi, for Research
Fellowships. We also thank the Department of Chemistry for
instrumentation facilities. J.T.M. thanks the Louisiana Board of
Regents through Grant No. LEQSF-(2002-03)-ENH-TR-67 for
purchasing the APEX, CCD diffractometer, NSF-MRI Grant
No. 1228232 for purchase of the D8 Venture diffractometer,
and the Chemistry Department of Tulane Univ. for supporting
the X-ray laboratory. We thank Dr. M. Kumaravel and Dr. G. S.
Ananthnag for their assistance in verifying the experimental
data.
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DOI: 10.1021/acs.inorgchem.6b01094
Inorg. Chem. XXXX, XXX, XXX−XXX