Half Sandwich Electron Deficient N,N′,N′′-Triarylguanidinatoruthenium(II) Complexes: Syntheses, Reactivity Studies, and Structural Aspects

Article abstract of DOI:10.1002/ejic.201900616

Three symmetrical N,N′,N′′-triarylguanidinatoruthenium(II) complexes, [(η⁶-p-cymene)RuCl{κ²(N,N′)((ArN)₂C-N(H)Ar)}] (Ar = 2-(CF₃)C₆H₄ (1), 4-(CF₃)C₆H₄ (2) a

Full text of DOI:10.1002/ejic.201900616

A Journal of
Accepted Article
Title: Half Sandwich Electron Deficient N,N′,N″-
Triarylguanidinatoruthenium(II) Complexes: Syntheses, Reactivity
Studies and Structural Aspects
Authors: Robin Kumar, Rishabh Ujjval, and Natesan Thirupathi
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To be cited as: Eur. J. Inorg. Chem. 10.1002/ejic.201900616
Link to VoR: http://dx.doi.org/10.1002/ejic.201900616

10.1002/ejic.201900616
European Journal of Inorganic Chemistry
Half
Sandwich
Electron
Deficient
N,N,N-
Triarylguanidinatoruthenium(II)
Complexes:
Syntheses,
Reactivity Studies and Structural Aspects
Robin Kumar,[a] Rishabh Ujjval,[a] and Natesan Thirupathi[a]
[a] Prof. N. Thirupathi, Dr. R. Kumar, R. Ujjval
Department of Chemistry, University of Delhi, Delhi 110 007, India
Email: tnat@chemistry.du.ac.in, thirupathi_n@yahoo.com
1
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10.1002/ejic.201900616
European Journal of Inorganic Chemistry
Abstract Three symmetrical N,N,N-triarylguanidinatoruthenium(II) complexes, [(6-p-
cymene)RuCl{2(N,N)((ArN)2CN(H)Ar)}] (Ar = 2-(CF3)C6H4 (1), 4-(CF3)C6H4 (2) and
3,5-(CF3)2C6H3 (3)) were isolated in good yields. The reaction of 3 with NaOAc, NaN3 and
KSCN afforded [(6-p-cymene)RuX{2(N,N)((ArN)2CN(H)Ar)}] (X = OAc (4), N3 (5) and
an admixture of SCN (6) and NCS (7)) respectively in very good yields. On the other hand,
metathesis reaction of 3 with AgSbF6 in the presence of MeCN afforded [(6-p-
cymene)Ru(MeCN){2(N,N)((ArN)2CN(H)Ar)}][SbF6] (8) in good yield. Complex 5 upon
treatment with diethylacetylenedicarboxylate
and bis(diphenylphosphino)acetylene
[(6-p-
separately afforded guanidinate(1)
complex,
cymene)Ru(N3C2(C(O)OEt)2){2(N,N)((ArN)2CN(H)Ar)}] (9) and guanidinate(2)
complex, [(6-p-cymene)Ru{2(N,N)((ArN)2CNAr)}(1P-Ph2PCCPPh2)] (10) in good
yields. The formation 9 versus 10 is ascribed to the subtle difference in the electron richness
of alkynes. The new complexes were characterized by analytical, IR and NMR spectroscopy
and single crystal X-ray diffraction. Complex 3 catalyses [3+2] cycloaddition reaction
involving phenylacetylene and 4-tolyl azide to afford an admixture of 1,4- and 1,5-
disubstituted 1,2,3-triazoles, 23 and 24 in 99% conversion.
Introduction
Metal complexes of N-susbstituted guanidinates have been widely studied in the past due to
their relevance in the fields of inorganic, organometallic, and materials chemistry.[1,2]
Additionally, these complexes have been invoked as intermediates in metal catalyzed
guanylation of amines with carbodiimides for guanidine synthesis.[3] Synthetic, structural
aspects, reactivity studies and applications of guanidinate complexes of platinum group
metals have been reviewed recently by Francos and Cadierno.[4] Numerous
guanidinatoruthenium(II)
complexes
of
symmetrical
N,N,N-triphenylguanidine,
2
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10.1002/ejic.201900616
European Journal of Inorganic Chemistry
[(PhNH)2C=NPh] have been prepared and stucturually characterized.[5] Subsequently, half
sandwich guanidinatoruthenium(II)-, rhodium(III)- and iridium(III) complexes of
symmetrical N,N,N-triarylguanidines, [(ArNH)2C=NAr] were prepared by us and others
with the objectives aimed at understanding their structures in solid state and in solution and to
further understand their utility as catalysts in base free and base assisted transfer
hydrogenation reactions.[611]
Half sandwich ruthenium(II)/osmium(II)- and bis(allyl)ruthenium(IV) complexes of
unsymmetrical N,N,N-trisubstituted guanidines, [(iPrNH)2C=NR] (R = Variously
substituted aryl rings, C(O)R; R = 2-thienyl and 2-furyl) have been prepared and key
complexes have been structurally characterized. Further, the utility of these complexes as
catalysts in base free isomerization of allylic alcohols, dehydration of aldoximes and as
anticancer agents was explored.[1215] Diruthenium complexes of both acyclic and cyclic
guanidinates and half sandwich ruthenium(II) complexes of cyclic guanidinates have been
studied with the objectives aimed at understanding the structural and magnetic properties of
the former complexes and the structural aspects and catalytic utility of the latter complexes in
isomerization of 1-octen-3-ol into octane-3-one.[16]
In the present investigation, we report syntheses and characterization of 13.
Reactivity studies of complex 3 was carried out with acetato, azido and isothiocyanato and
thiocyanato nucleophiles which resulted in the formation of complexes 47. A copper(I)
catalyzed click reaction involving organic azides and alkynes to afford 1,4-disubstituted
1,2,3-triazoles selectively is known since the pioneering work of Fokin, Sharpless and Meldal
published in 2002.[17,18] Such reactions involving metal azide/alkyne known as early as 1974,
metal alkyne/organic azide, metal azide/metal alkyne, popularly known as iclick reaction, are
the emerging reactions for metal triazolate complexes that could contain either a metal-
nitrogen bond or a metal-carbon bond depending upon the reaction partners.[1925] Continuing
3
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10.1002/ejic.201900616
European Journal of Inorganic Chemistry
our interests in understanding the reactions of guanidinatometal azido complexes with
alkynes and factors that dictate the stereochemistry of o-substituted N,N,N-
triarylguanidinato ligand in the resulting triazolate complexes,[8,11] we report herein the
reactions
of
5
with
diethylacetylenedicarboxylate
(DEAD)
and
bis(diphenylphosphino)acetylene (DPPA) which afforded two distinct products, namely 9 and
10 respectively. The utility of 3 as catalyst in click reaction involving phenyl acetylene and 4-
tolyl azide was also explored.
Results and Discussion
Syntheses The reaction of [(6-p-cymene)Ru(-Cl)Cl]2 with symmetrical N,N,N-
triarylguanidines, L1L3 in methanol in presence of NaOAc afforded 13 respectively as
orange solids in 82% yields (see Scheme 1). The separate reactions of 3 with excess of
NaOAc, NaN3, and KSCN in methanol or ethanol at RT for 24 h afforded the corresponding
acetato (4), azido (5), and isomeric mixture of thiocyanato (6) and isothiocyanato (7)
complexes respectively as orange solids in 89% yields (see Scheme 2).
Scheme 1
Cl
1/2
Ru
Ar
N
Cl
Ar
2
Ru
Ar
H
Ar
N
N
H
N
Cl
2 NaOAc
Methanol, RT, 24 h
Ar
Ar
N
N
H
Ar
2-(CF3)C6H4
4-(CF3)C6H4
3,5-(CF3)2C6H3
L1
L2
L3
1
2
3
4
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European Journal of Inorganic Chemistry
Scheme 2
Ar
Ar
MX
Ru
N
Ru
Ar
N
Cl
X
Ar = 3,5-(CF3)2C6H3
Ar
Ar
N
N
N
N
H
Ar
H
3
47
X
OC(O)Me
N3
4
5
6
7
SCNa
NCSa
a Isolated as a mixture of 6 and 7
Complex 3 upon treatment with AgSbF6 in MeCN in dark for 24 h at RT afforded
cationic complex 8 as yellow orange solid in 85% yield (see Scheme 3). Metal azido
complexes have been used extensively as metallo-dipolarophile in azide-alkyne cycloaddition
(AAC) reactions which afforded the respective triazolate complexes under mild reaction
condition.[1925] Considerable efforts have been expended in understanding the factors that
promote AAC reactions involving ruthenium(II) azido-dipolarophile.[8,25] Hence, complex 5
was separately treated with DEAD and DPPA in CH2Cl2 at RT for 24 h which afforded 9 as
anticipated and 10 as unanticipated products in the form of orange solid in 86% and 87%
yields respectively (see Scheme 4 ).
The reaction of 5 with DPPA can possibly afford an acyclic intermediate A through
the cleavage of RuNimine bond of the guanidinate ligand (see Figure 1). The intermediate A
upon amine-imine tautomerisation can give rise to another acyclic intermediate B which
subsequently undergoes ring closure of the guanidinate ligand assisted by elimination of HN3
to afford guanidinate(2) complex, 10. Thus, DPPA merely acts as a Lewis base rather than
as a dipolarophile in the reaction depicted in Scheme 4 but once coordinated to the Ru(II)
atom in the intermediate B, it reduces -basicity of the metal thereby stabilizing the
5
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10.1002/ejic.201900616
European Journal of Inorganic Chemistry
intermediate B. The transformation of the guanidinate(1) to the guanidinate(2) in the
primary coordination sphere of the metal shown through the conversion of 5 to 10 appears to
be partly driven by electron deficient nature of the guanidinate(1) ligand in the former
complex. Other hypothetical complexes such as C, which would have formed if AAC has
occurred and phosphazide intermediate D or iminophosphorane species E which would have
formed if Staudinger reaction has occurred have not been formed (see Figure 2).[19,26]
Scheme 3
SbF6
AgSbF6/MeCN
Ar
Ar
Ru
Ru
N
N
Cl
N
Ar = 3,5-(CF3)2C6H3
Ar
Ar
Me
N
N
N
H
N
H
Ar
Ar
3
8
Scheme 4
Ar
Ru
EtO(O)C-CC-C(O)OEt
OEt
O
N
N1
N2
N
Ar
N
N
H
Ar
OEt
O
9
Ar = 3,5-(CF3)2C6H3
Ar
Ru
N
N3
Ar
N
N
H
PPh2
Ar
Ph2P-CC-PPh2
Ar
C
Ru
C
N
5
P
Ar
Ph
N
Ph
HN3
N
Ar
10
6
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Figure 1
Ph2P
Ph2P
N
N
Ru
N
N
Ru
N
N
P
P
Ph
Ar
Ph
Ph
N
Ph
N
Ar
H
N
N
N
H N
Ar
Ar
Ar
Ar
A
B
Figure 2
Ar
Ar
Ru
Ar
Ru
Ar
N
N
N
(N)n
N
PPh2
Ar
Ar
N
N
N
H
N
H
PPh2
C
N
PPh2
C
PPh2
n = 3 (D) and 1 (E)
C
It is to be noted that the transformation of metal bound N,N,N-
triacetylguanidinate(1) to metal bound N,N,N-triacetylguanidinate(2) was shown to occur
only in the presence of Ag2O as an external base.[7] Further, the transformation of metal
bound N,N,N-trialkylguanidinate(1) to metal bound N,N,N-trialkylguanidinate(2) was
reported to occur in the presence of additional reagents such as LiNMe2, MeMgBr or
XyNC.[27,28] Thus, the deprotonation of metal bound guanidinate(1) in 5 upon reaction with
DPPA in the formation of 10 shown in Scheme 4 illustrates non-innocent nature of ancillary
7
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10.1002/ejic.201900616
European Journal of Inorganic Chemistry
ligand of metal azido complexes in [3+2] cycloaddition reaction with alkynes and this
observation is unprecedented in the literature.
Molecular Structures Molecular structures of 14, 5MeOH, 6, 7CHCl3, 8MeOH,
910 with atom labeling Scheme are shown in Figures 37. The CF3 group in some
molecular structures depicted revealed large unsymmetrical ellipsoids due to thermal
disorder. The coordination environment around the Ru(II) atom in 13 is identical to that
observed
in
previously
reported
complexes
[(6-p-
cymene)RuCl{2(N,N)((ArN)2CN(H)Ar}] (Ar = Ph (11),[6] 2-MeC6H4 (12) and 4-MeC6H4
(13)[8]). When the guanidinate ligand contains ortho substituted aryl rings such as that present
in 1 and related complex 12, and [(5-C5Me5)M{2(N,N)((ArN)2CN(H)Ar}] (M = Rh, Ar =
2-(CF3)C6H4 (14) and M = Ir, Ar = 2-MeC6H4 (15)), in principle, four types of conformers are
possible namely syn-syn, syn-anti, anti-syn, and anti-anti as discussed in our previous
publications (see also Figure S1 in the Supporting Information, SI).[8,10,11] Accordingly, the
guanidinate ligand in 1 revealed syn-syn conformation.
The bond parameters pertinent to the guanidinate ligand in structurally characterized
complexes are listed in Table 1 and these parameters in 4, 5MeOH, 6, 7CHCl3, 8MeOH and
9 are comparable with the corresponding parameters found in 3. Interestingly, one of the
coordinated N atoms of the guanidinate in all three crystallographically distinct molecules of
3 deviates significantly from planarity and this feature is even more pronounced in 4 while
the other coordinated N atom in both complexes is planar. The degree of pyramidality of one
of the coordinated N atoms in 5MeOH is smaller than that in 3 probably due to greater -
donor but poorer -donor characters of the coordinated N atom of the guanidinate ligand in
the former complex.[29] This stereochemical difference could be ascribed to a better -donor

strength of Cl in 3 than N3 in 5MeOH. The NH proton of guanidinate ligand in 4 is
involved in intermolecular NHO hydrogen bond with ketonic oxygen atom of the acetate
8
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10.1002/ejic.201900616
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moiety from the adjacent molecule related by the glide plane in the crystal lattice (N3O2 =
2.875 Å, H3O2 = 2.052 Å, N3H3O2 = 160.09; see Figure S2 in the SI).
1
2
3
Figure 3 Molecular structures of 13 at the 30% probability level. Two and three molecules
are found in the crystal lattices of 2 and 3 respectively but only one molecule is shown in
each case for clarity. Only H atom of the N(H)Ar moiety is shown for clarity.
9
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4
5MeOH
Figure 4 Molecular structures of 4 and 5MeOH at the 30% probability level. Methanol in
5MeOH and H atoms other than that in N(H)Ar moiety in both complexes are not shown
for clarity.
7CHCl3
6
Figure 5 Molecular structures of 6 and 7CHCl3 at the 30% probability level. CHCl3 in
7CHCl3 and H atoms other than that in N(H)Ar moiety in both complexes are not shown
for clarity.
10
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8MeOH
Figure 6 Molecular structure of 8MeOH at the 30% probability level. The counteranion,

SbF6 and solvent have been omitted and only H atom of the N(H)Ar moiety is shown for
clarity.
9
10
Figure 7 Molecular structures of 9 and 10 at the 30% probability level. Only H atom of the
N(H)Ar moiety in 9 is shown for clarity.
11
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Table 1 Comparison of structural features of 14, 5MeOH, 6, 7CHCl3, 8MeOH and 9.
CN
(Å)
CN
(Å)
N(coordinated)
N(noncoordinated)
a
(deg)
Complex
(deg)
(deg)
0.000(6)
0.081(6)
0.062(6)
0.057(6)
0.053(7)
0.066(7)
0.057(8)
0.037(7)
0.033(6)
0.033(6)
0.041(5)
355.0, 359.7
353.7, 360.0
354.9, 360.0
344.8, 360.0
346.0, 359.9
344.2, 360.0
341.3, 359.2
350.4, 359.4
353.4, 359.8
345.4, 359.9
360.0
360.0
357.9
360.0
360.0
360.0
360.0
360.0
360.0
360.0
71.9
34.7
50.3
42.3
38.3
39.9
39.9
14.3
33.7
30.8
1
2 (molecule 1) 0.023(6)
2 (molecule 2) 0.015(6)
3 (molecule 1) 0.023(7)
3 (molecule 2) 0.014(7)
3 (molecule 3) 0.007(7)
0.017(7)
0.005(6)
0.007(6)
0.008(3)
4
5MeOH
6
7CHCl3
8MeOH
9
0.022(13) 0.048(13)
0.021(8) 0.054(8)
348.3, 359.7
354.1, 354.5
360.0
359.5
19.7
18.3
a = Dihedral angle between the HNC(Ar) plane and the chelating –N-C=N- plane
The bond parameters around the azido unit in 5MeOH are comparable with the
identical unit present in [(6-p-cymene)Ru(N3){2(N,N)((ArN)2CN(H)Ar}] (Ar = 4-
MeC6H4 (16)).[8] An intermolecular NHO and OHN hydrogen bonds are present
between MeOH and (i) H atom of the amino moiety and (ii) terminal N atom of the azido
moiety (N3O1 = 2.829 Å, H3O1 = 2.119 Å, N3H3O1 = 137.22; O1N6 = 2.964 Å,
H1N6 = 2.284 Å, O1H1N6 = 151.25; see Figure S3 in the SI). The azido unit in
5MeOH can exist in two resonance forms namely F and G as illustrated in Figure
8.[11,25b,25e,30] The resonance form F was shown to be more suitable for AAC reaction while
12
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European Journal of Inorganic Chemistry
the metal bound N atom of the azido moiety in resonance form G was shown to be more
suitable for an attack by an electrophile such as proton (see also Figure 1).[25b,25e,30]
Figure 8
[M]
[M]
N
N
N
N
N
N
F
G
Previously, only two pairs of cationic thiocyanatoruthenium(II) linkage isomers,
[(6-p-cymene)Ru(2,2-bipyridine)X]PF6 (X
=
SCN (17) and NCS (18)) and
[Ru(terpy)(tbbpy)X] (terpy = 2,2:6,2-terpyridine, tbbpy = 4,4-di-tert-butyl-2,2-bipyridine,
X = SCN (19) and NCS (20)) have been structurally characterized.[31,32] Hence, 6 and
7CHCl3 represent the first pair of structurally characterized neutral thiocyanatoruthenium(II)
linkage isomers to be reported in the literature. The bond parameters around the SCN ligand
in 6 are comparable with those parameters reported for the same ligand in 17 and 19 except a
smaller RuEC angle found in the former complex (E = S, 100.50(17) (6) and 104.35(6)
(17), 106.7(5) (19); E = N, 165.7(2) (7) and 175.9(1) (18) 175.7(6) (20)). This difference
in RuEC angle between neutral versus cationic thiocyanatoruthenium(II) complexes
mentioned above could partly be ascribed to difference in the coordination environment
around the metal atom and partly be ascribed to the packing forces as shall be outlined below.
The SCN ligand in 6 is involved in intermolecular NHN hydrogen bond involving
N end of the thiocyanate and H atom of the amino moiety of the guanidinate ligand in the
neighboring molecule related by a glide plane (NN = 2.905 Å, HN = 2.064 Å, NHN =
165.8; see Figure S4 in the SI). The NCS ligand in 7 is involved in intermolecular NHS
hydrogen bond involving S atom of the thiocyanate and H atom of the amino moiety of the
guanidinate ligand in the neighboring molecule related by a 2-fold screw axis (NS = 3.316
Å, HS = 2.470 Å, NHS = 168.22; see Figure S5 in the SI). The N bonded isomer of
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metal thiocyanate complexes was shown to be a thermodynamic product while the S bonded
isomer was shown to be a kinetic product.[32,33,34] However, S-bonded isomer of metal
thiocyanate complexes was frequently found in the crystal lattice as the stabilization energy
obtained through intermolecular interaction is greater than the energy difference between the
gas phase monomers of both the linkage isomers.[33,34]
The Lewis base, MeCN is coordinated to the Ru(II) atom in 8MeOH in place of Cl in

its precursor 3. Further, SbF6 is present outside the coordination sphere of the metal in
8MeOH. The triazolate ligand in 9 is coordinated to the Ru(II) atom through the central N
atom (N2) and this coordination mode is believed to be the result of the formation of a
thermodynamic product.[35,36] The structurally characterized N1 coordinated triazolate
complexes are uncommon with a few exceptions[37] while N2 coordinated triazolate
complexes are common. The bond parameters associated with the guanidinate ligand in
8MeOH and 9 resemble with the corresponding parameters discussed for the same ligand in
3.
The Ru(II) atom in 10 is surrounded by a guanidinate(2) ligand, one end of the
DPPA and the 6-p-cymene ring. Previously, molecular structures of [(6-p-
cymene)Ru{2(N,N)((RN)2C=NR)}(PPh3)] (R
=
C(O)Me; 21) and [(4-1,5-
cyclooctadiene)RuCl{2(N,N)((RN)2C=NR))}] (R = Ph; 22) that contained a chelating
guanidinate(2) were reported by Henderson and Bailey and co-workers, respectively.[7,38]
The poor quality of X-ray data of 21 precluded the publication of key bond parameters and
moreover, key bond parameters of 22 remain unpublished. Therefore, complex 10 represents
the first fully characterised guanidinatoruthenium(II) complex that contain a doubly
deprotonated guanidinate(2) ligand. As anticipated, the CN distance, 1.304(6) Å involving
non-coordinated N atom of the CN3 unit in 10 is shorter than the CN distances, 1.357(6) and
1.385(6) Å involving the pair of coordinated N atoms. Further, both the RuN distances,
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2.091(3) and 2.108(3) Å of the guanidinate ligand in 10 are comparable with each other
within 3 cut off which contrasts with the unequal RuN bond distances observed in 3
(2.088(4)/2.143(3) Å (molecule 1), 2.084(3)/2.142(4) Å (molecule 2) and 2.104(4)/2.148(4)
Å (molecule 3)). The C atom and one of the coordinated N atoms of the CN3 unit in 10 is
planar while the remaining coordinated N atom deviates significantly from planarity (N =
349.5). Thus, one coordinated N atom acts as a pure -donor and while the other
predominantly acts as -donor contaminated with a slight amount of -donor character.[21]
The values of both CN 0.053(8) Å and CN 0.054(8) Å found in 10 are comparable with the
corresponding values observed for 3 within the 3 cut off. The bond parameters pertinent to
DPPA in 10 are comparable with those parameters published for the related complex, [(6-p-
cymene)RuCl2(1P-Ph2PCCPPh2)].[39]
Spectroscopic Studies IR spectra of all new complexes except that of 10 revealed
one band in the range 32953447 cm1 attributable to the (NH) stretch. In addition, the IR
spectrum of 4 revealed two bands at 1534 and 1342 cm1 ascribed to a(OCO) and s(OCO)
stretches, respectively. The  = a(OCO)  s(OCO) value of 192 cm1 supports the
presence of a hydrogen bonded monodentate acetate coordination mode as found in the solid
state (see above).[40] An intense band was also observed at 2033 cm1 for 5 which is ascribed
to the (N3) stretch.[19a] The IR spectrum of isomeric mixture of 6 and 7CHCl3 revealed a
band at 2038 cm1. The value of (SCN) stretch of thiocyanate is greater for the S bound
isomer ( 2100 cm1, sharp) than for the N bound isomer ( 2050 cm1, more intense and
broad) although this rule is not universal.[32,34] The bandwidth at half height for the
aforementioned band is 7 cm1 and further both the S and N ends of the thiocyanate ligand in
6 and 7CHCl3 are involved in intermolecular NHN and NHS hydrogen bonding,
respectively. Thus, the magnitude of difference in (SCN) stretch between 6 and 7CHCl3
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could lie well within 7 cm1. Complex 9 revealed one band at 1731 cm1 attributable to the
(CO) stretch of the ester moiety.
1
The H NMR spectrum of 1 revealed the presence of three species in about
0.14:1.00:0.11 ratios and the presence of three species was also independently verified by 19F
NMR spectroscopy. The three solution species are assigned to any three isomers from syn-
syn, syn-anti, anti-syn, and anti-anti isomers, most likely to the former three isomers (see
Experimental section and Figure S1 in the SI). The formation of syn-anti and anti-syn
isomers from syn-syn isomer which is observed in solid state is likely due to guanidine
centered rearrangement in solution involving an acyclic intermediate as previosusly discussed
1
by two of us.[811] VT H NMR spectra of previously known complex 12 revealed the
presence of three species in solution and these species were suggested to arise from the
restricted N2CN(H)Ar single bond rotation yielding syn-syn, syn-syn a and syn-syn b
rotamers.[8] The difference in the nature of solution species between 1 and 12 is ascribed to
the difference in greater effective van der Waals radius of CF3 groups in the former complex
than that of Me groups in the latter (2.20 Å versus 1.80 Å).[41]
19
13
1H, F and C NMR spectra of 25 revealed the presence of a single species in
solution as anticipated due to the presence of a symmetrically substituted aryl rings in the
1
guanidinate ligands. The H NMR spectrum of isomeric mixture of 6 and 7 revealed the
presence of two species in about 1.00:0.37 ratio (see Experimental section). The major
species is tentatively assigned to the S bound isomer as this isomer is more soluble in CDCl3
1
and the minor species is assigned to the N bound isomer. The H NMR spectrum of cationic
complex 8 revealed the presence of four species in about 1.00:0.10:0.45:0.39 ratios. The
presence of symmetrical aryl rings in the guanidinate moiety of 8 suggests that these four
species could not have originated for the reasons putforward for 1 but possibly could have
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originated from any four out of six possible rotamers that arise from the p-cymene ring
rotation about the metal center.[8]
1
The H NMR spectrum of 9 revealed the presence of two species in about 1.00:0.05
ratio (see Experimental Section). These two species could arise due to either linkage
isomerism caused by the triazolate ligand (N1 versus N2 coordination) or the p-cymene ring
1
rotation about the metal as discussed previously for 8. If the observed H NMR spectral
pattern is due to linkage isomerism, one would then anticipate three quartets for CH2CH3
protons with two of these quartets being of equal intensity and three triplets for CH2CH3
1
protons with two of these triplets being of equal intensity.[36] The H NMR spectrum of 9
revealed the presence of two triplets for CH3 protons and two quartets for CH2 protons of the
C(O)OEt moiety both in about 1.00:0.05 ratio which suggest the cause of two isomers being
the p-cymene ring rotation about the metal centre.[8]
13
19
31
Multinuclear (1H, C, F and P) NMR spectra of 10 revealed the presence of a
single species in solution. The 31P{1H} NMR spectrum of 10 revealed two singlets located at
 31P 18.05 and 31.34 ppm assignable to coordinated and pendant P nuclei respectively. The
 31P shift value found for coordinated P in 10 is downfield shifted while the  31P shift value
31
found for pendant P is somewhat comparable to the corresponding  P shifts reported for
[(6-p-cymene)RuCl2(1P-Ph2PCCPPh2)] ( (31P) = 0.4 (s, RuP), 34.2 (d, JPP = 3.6 Hz,
pendant P)).[39]
Ruthenium catalyzed azide alkyne cycloaddition (RuAAC) The reaction of organic
azide with terminal alkyne in the presence of metal salts was shown to afford 1,4- and 1,5-
disubstituted triazoles under mild reaction condition. This reaction is known as metal
catalyzed AAC reaction.[42,43] There is a constant demand for newer catalysts that selectively
affords either 1,4- or 1,5-disubstituted triazoles from the reaction involving terminal alkynes
and organic azides. Fokin and Sharpless first reported the use of [(5-Cp*)Ru(PPh3)2Cl] as a
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catalyst for AAC involving alkyl azide and terminal/internal alkynes that afforded 1,5-
disubstituted triazoles in > 80% yield.[44] Since then, RuAAC has been studied with alkyl
azides/terminal or internal alkynes which afforded exclusively either 1,5- or 1,4-disubstituted
triazoles or a mixture of these triazoles.[45,46]
We wanted to test catalytic efficacy of 3 in RuAAC reaction involving 4-tolyl azide
and phenyl acetylene as coupling partner (see Table 2). This reaction was carried out in
CH2Cl2 at RT for 24 h in the absence of catalyst and AgOAc as additive which afforded no
trace of triazole (entry 1). Further, the aforementioned reaction carried out in the presence of
either AgOAc alone or a mixture of [(6-p-cymene)Ru(-Cl)Cl]2 and AgOAc (Ru:Ag = 1:10)
in CH2Cl2 at RT for 24 h which afforded no trace of triazole (entries 2 and 3). RuAAC
carried out in the presence of 3 and in the absence of AgOAc also did not give triazole (entry
4). Pleasingly, the combination of 3 and AgOAc (Ru:Ag = 1:10) in CH2Cl2 at RT for 24 h
afforded a mixture of 1,4- and 1,5-disubstituted 1,2,3-triazoles (23 and 24) in 99% conversion
with the isomer ratio being 73:27 (entry 5). The triazole 23 was isolated from the reaction
mixture by column chromatography in 62% yield. The composition of 23 was confirmed by
melting point measurement, 1H and 13C{1H} NMR spectroscopy and SCXRD (see Figure S6
in the SI). The use of 11 in place of 3 in the above-mentioned click reaction gave a mixture of
23 and 24 in 98% conversion with their ratio being 55:45 (entry 6). Complexes 1 and 2 were
also screened for RuAAC reaction outlined in Table 2, but neither of the triazoles were
obtained in reasonable yields from these reactions. The formation of a mixture of 23 and 24 is
anticipated to arise from putative intermediates H and I, respectively (see Figure 9).45a
Conclusions
Complexes 13 were isolated in good yields following the established method. Complex 3

was subjected to nucleophilic substitution reaction with OAc, N3 , and SCN which afforded
4, 5 and an admixture of 6 and 7 in good yields. The metathesis reaction of 3 with AgSbF6 in
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the presence of MeCN afforded cationic complex 8 in 85% yield. The AAC reaction of 5
with DEAD gave the N2 bound triazolate complex 9 in 86% yield while the reaction of 5
with DPPA gave a novel guanidinate(2) complex 10 in 87% yield. The new complexes were
characterized by analytical, IR and NMR (1H, 13C and 19F) spectroscopic techniques. Further,
molecular structures of eleven new compounds were determined by SCXRD. The guanidinate
ligand in 1 revealed syn-syn conformation. The isolation of linkage isomers 6 and 7 and their
structure determination through SCXRD is a noteworthy result reported in this manuscript.
Further, complex 10 represents the first fully characterized guanidinatoruthenium(II) complex
which contain guanidinate(2) ligand to be reported in the literature. The presence of more
than one solution species was shown to depend upon (i) steric property and substitution
Table 2 Results of RuAAC of phenylacetylene and 4-tolyl azide.
Ph
H
Catalyst
5
5
H
Ph
(10 mol %)
1
N1 Ar +
N2
4
4
PhC
+
N Ar
N2
24
CH N3Ar
3N
3
N
Additive
Ar = C6H4Me-4
23
Entry
Catalyst
Additive
Conversiona (%)
23/24 ratioa
1
2
3
4
Blank
0
0
0
0
0/0
0/0
0/0
0/0

AgOAc
AgOAc

[(6-p-cymene)Ru(-Cl)Cl]2
3

5
6
AgOAc
AgOAc
99
98
73(62b)/27
55/45
3
11
aConversion and ratio of 23 and 24 were estimated by 1H NMR spectroscopy.
bIsolated yield.
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pattern of the aryl rings of the guanidinate ligand in 1 and (ii) steric encumbrance around the
metal which induces p-cymene ring rotation as found in 8 and 9. The utility of 3 as catalyst in
RuAAC reaction involving 4-tolyl azide and phenyl acetylene was briefly explored which
afforded 1,4-disubstituted triazole 23 in 62% isolated yield.
H
I
Figure 9 Plausible intermediates H and I responsible for the formation of 1,4- and 1,5-
troazoles, respectively formed during the click reaction
Experimental section
[(6-p-cymene)RuCl{2(N,N)((ArN)2CN(H)Ar}] (Ar = 2-(CF3)C6H4; 1) Guanidine L1
(80.2 mg, 0.163 mmol) was dispersed in methanol (10 mL) in a 25 mL round bottom (RB)
flask and the content in the flask were stirred at RT to afford a clear solution. NaOAc (13.4
mg, 0.163 mmol) was added to the aforementioned solution and stirred. Subsequently, [(6-p-
cymene)Ru(µ-Cl)Cl]2 (50.0 mg, 0.082 mmol) was added all at once to the aforementioned
mixture and stirred at RT for 24 h. The reaction mixture was filtered and the filtrate
evaporated under vacuum to afford the solid. The solid was dissolved in CH2Cl2 and filtered
to remove NaCl as white precipitate. The filtrate was layered with n-hexane and the resulting
solution stored at RT to afford 1 as orange needle shaped crystals. Yield: 84% (99.4 mg,
0.131 mmol). Mp: 191 C. Anal. Calcd for C32H27ClF9N3Ru (Mw: 761.08): C, 50.50; H, 3.58;
N, 5.52. Found: C, 50.50; H, 3.74; N, 5.38. IR (KBr): = 3447 (m, NH), 1546 (s, C=N),
1483 (s, CF3, str, asym), 1116 (s, CF3, str, sym), 843 (w, CF3, def, asym) cm–1. The 1H NMR
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spectrum of 1 revealed the presence of three species, hereafter indicated as isomers 1, 2 and 3
1
in about 0.14:1.00:0.11 ratios as estimated from the integrals of alkyl protons. H NMR
(CDCl3, 400 MHz, 298 K):  = 0.93, 1.03 (each d, JH,H = 7.2 Hz, 2  6H, CH(CH3)2, isomers
1 and 2, respectively), 1.20 (d, JH,H = 6.8 Hz, 6H, CH(CH3)2, isomer 3), 1.69 (s, 2  3H, CH3,
isomers 1 and 3), 1.76 (s, 3H, CH3, isomer 2), 2.51 (m, 1H, CHMe2, isomer 2), 2.73 (m, 2 
1H, CHMe2, isomers 1 and 3), 4.98 (d, JH,H = 6.0 Hz, 2H, C6H4, isomer 1), 5.14 (d, JH,H = 6.0
Hz, 2H, C6H4, isomer 3), 5.18 (d, JH,H = 6.0 Hz, 2H, C6H4, isomer 2), 5.24 (d, JH,H = 6.0 Hz,
2H, C6H4, isomer 1), 5.45 (d, JH,H = 6.0 Hz, 2H, C6H4, isomer 2), 5.49 (d, JH,H = 6.0 Hz, 2H,
C6H4, isomer 3), 5.52 (s, 2  1H, NH, isomers 1 and 3), 5.63 (s, 1H, NH, isomer 2), 6.67 (t,
JH,H = 7.8 Hz, 1H, ArH, isomer 2), 6.75 (t, JH,H = 7.6 Hz, 1H, ArH, isomer 1), 6.85 (t, JH,H
=
7.4 Hz, 1H, ArH, isomer 3), 7.00 (t, JH,H = 7.6 Hz, 1H, ArH, isomer 2), 7.057.18 (m, 3 
4H, ArH, isomers 13), 7.31 (dt, JH,H = 7.7 Hz, JH,H = 1.4 Hz, 2H, ArH, isomer 2), 7.40 (d,
JH,H = 8.0 Hz, 3  1H, ArH, isomers 13), 7.44 (br, 2  2H, ArH, isomers 1 and 3), 7.48 (dd,
JH,H = 8.0 Hz, JH,H = 1.6 Hz, 1H, ArH, isomer 2), 7.68 (d, JH,H = 7.2 Hz, 2  2H, ArH,
isomers 1 and 3), 7.78 (d, JH,H = 8.0 Hz, 2H, ArH, isomer 2), 8.12 (d, JH,H = 8.0 Hz, 2  2H,
19
ArH, isomers 1 and 3) ppm. F NMR (CDCl3, 376.5 MHz, 298 K):  = –61.92 (s, 3F, CF3,
isomer 1), –61.52 (s, 2  3F, CF3, isomers 2 and 3), –59.52 (s, 6F, CF3, isomer 3), –59.28 (s,
6F, CF3, isomer 2), –58.60 (s, 6F, CF3, isomer 1) ppm. MS (ESI+) m/z [ion]: 726 [M – Cl]+,
492 [L1H]+.
[(6-p-cymene)RuCl{2(N,N)((ArN)2CN(H)Ar}] (Ar = 4-(CF3)C6H4; 2) Complex 2 was
prepared from L2 (80.2 mg, 0.163 mmol), NaOAc (13.4 mg, 0.163 mmol), and [(6-p-
cymene)Ru(µ-Cl)Cl]2 (50.0 mg, 0.082 mmol) in methanol (10 mL) by following a procedure
analogous to that described for complex 1. The sample was crystallized from a mixture of
CH2Cl2 and toluene at RT over the period of two days to afford 2 as orange needle shaped
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crystals. Yield: 82% (106.8 mg, 0.1404 mmol). Mp: 221 C (decompn). Anal. Calcd for
C32H27ClF9N3Ru (Mw: 761.08): C, 50.50; H, 3.58; N, 5.52. Found: C, 50.43; H, 3.45; N, 5.69.
IR (KBr): = 3423 (m, br, NH), 1512 (m, C=N), 1324 (vs, CF3, str, asym), 1105 (s, CF3, str,
sym), 834 (m, CF3, def, asym) cm–1. 1H NMR (CDCl3, 400 MHz, 298 K):  = 1.23 (d, JH,H
=
6.8 Hz, 6H, CH(CH3)2), 2.25 (s, 3H, CH3), 2.69 (m, 1H, CHMe2), 5.19 (d, JH,H = 4.8 Hz, 2H,
C6H4), 5.40 (d, JH,H = 5.2 Hz, 2H, C6H4), 6.24 (s, 1H, NH), 6.83 (d, JH,H = 8.0 Hz, 2H, ArH),
7.14 (d, JH,H = 7.6 Hz, 2H, ArH), 7.21, 7.38 (each d, JH,H = 7.6 Hz, 2  4H, ArH) ppm.
13C{1H} NMR (CDCl3, 100.5 MHz, 298 K):  = 19.26 (CH3), 22.50 (CH(CH3)2), 31.62
(CHMe2), 78.94, 80.85, 98.56, 99.78 (p-cymene ArCH/ArC), 120.01, 123.36, 123.98 (q, JC,F
= 268.9 Hz, CF3), 124.45 (q, JC,F = 271.2 Hz, CF3), 124.86 (q, JC,F = 32.5 Hz, CCF3), 125.36
(q, JC,F = 32.9 Hz, CCF3), 125.96, 126.00, 126.20, 126.23, 140.38, 149.41, 152.78
(ArCH/ArC and C=N) ppm. 19F NMR (CDCl3, 376.5 MHz, 298 K):  = –62.20 (s, 3F, CF3),
–61.83 (s, 6F, CF3) ppm. MS (ESI+) m/z [ion]: 762 [M + H]+, 726 [M – Cl]+, 492 [L2H]+.
[(6-p-cymene)RuCl{2(N,N)((ArN)2CN(H)Ar}] (Ar = 3,5-(CF3)2C6H3; 3) Complex 3
was prepared from L3 (113.5 mg, 0.1633 mmol), NaOAc (13.4 mg, 0.163 mmol), and [(6-p-
cymene)Ru(µ-Cl)Cl]2 (50.0 mg, 0.082 mmol) in methanol (10 mL) by following a procedure
analogous to that described for 1. The sample was crystallized from a mixture of CH2Cl2 and
methanol at RT over the period of several days to afford 3 as orange needle shaped crystals.
Yield: 84% (127.6 mg, 0.1323 mmol). Mp: 215 C. Anal. Calcd for C35H24ClF18N3Ru (Mw:
965.08): C, 43.56; H, 2.51; N, 4.35. Found: C, 43.37; H, 2.34; N, 4.31. IR (KBr): = 3432
(br, NH), 1542 (m, C=N), 1376 (s, CF3, str, asym), 1278 (vs, CF3, str, sym), 1130 (s, CF3,
1
def, asym), 887 (w, CF3, str, sym) cm–1. H NMR (CDCl3, 400 MHz, 298 K):  = 1.24 (d,
JH,H = 6.8 Hz, 6H, CH(CH3)2), 2.23 (s, 3H, CH3), 2.68 (m, 1H, CHMe2), 5.27 (d, JH,H = 6.0
Hz, 2H, C6H4), 5.42 (d, JH,H = 6.4 Hz, 2H, C6H4), 6.43 (s, 1H, NH), 7.23 (s, 1H, ArH), 7.30
(s, 2H, ArH), 7.42 (s, 2H, ArH), 7.55 (s, 4H, ArH) ppm. 13C{1H} NMR (CDCl3, 100.5 MHz,
22
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298 K):  = 19.2 (CH3), 22.4 (CH(CH3)2), 31.7 (CHMe2), 79.7, 80.5, 97.1, 101.3 (p-cymene
ArCH/ArC), 116.7 (br), 117.7 (br), 121.4, 122.6 (q, JC,F = 273.1 Hz, CF3), 123.1 (q, JC,F
=
272.7 Hz, CF3) 123.4, 132.4, 132.5 (each q, JC,F = 33.9 Hz, CCF3), 137.8, 147.2, 152.5 (ArC
19
and C=N) ppm. F NMR (CDCl3, 376.5 MHz, 298 K):  = –63.55 (s, 6F, CF3), –63.06 (s,
12F, CF3) ppm. MS (ESI+) m/z [ion]: 969 [M – Cl + K]+, 930 [M – Cl]+, 696 [L3H]+.
[(6-p-cymene)Ru(OAc){2(N,N)((ArN)2CN(H)Ar}] (Ar = 3,5-(CF3)2C6H3; 4) Complex
3 (100.0 mg, 0.1036 mmol) was stirred with excess of NaOAc (849.8 mg, 10.36 mmol) in
methanol (10 mL) in a 25 mL RB flask fitted with a CaCl2 guard tube at RT for 24 h. The
volatiles were removed under vacuum to afford orange solid. The solid was dissolved in
CH2Cl2 and filtered to remove unreacted NaOAc and NaCl. The filtrate was layered with n-
hexane and the resulting solution stored at RT for 24 h to afford 4 as orange needle shaped
crystals. Yield: 89% (91.1 mg, 0.092 mmol). Mp: 215 C (decompn). Anal. Calcd for
C37H27F18N3O2Ru (Mw: 988.68): C, 44.95; H, 2.75; N, 4.25. Found: C, 44.74; H, 2.43; N,
4.28. IR (KBr): = 3423 (br, NH), 1597 (m, C=N), 1534 (br, OC(O), str, asym), 1380 (s,
CF3, str, asym), 1342 (s, OC(O), str, sym), 1282 (vs, (CF3, str, sym), 1127 (vs, CF3, def,
1
asym), 886 (w, CF3, str, sym) cm–1. H NMR (CDCl3, 400 MHz, 298 K):  = 1.15 (d, JH,H
=
6.8 Hz, 6H, CH(CH3)2), 2.01 (s, 3H, OC(O)CH3), 2.06 (s, 3H, CH3), 2.55 (m, 1H, CHMe2),
5.38, 5.56 (each d, JH,H = 6.0 Hz, 2  2H, C6H4), 6.29 (s, 1H, NH), 7.06 (s, 2H, ArH), 7.25 (s,
13
1H, ArH), 7.44 (s, 2H, ArH), 7.63 (s, 4H, ArH) ppm. C{1H} NMR (CDCl3, 100.5 MHz,
298 K):  = 19.1 (CH3), 22.5 (CH(CH3)2), 23.9 (OC(O)CH3), 31.6 (CHMe2), 78.3, 81.1, 96.8,
99.5 (p-cymene ArCH/ArC), 116.6 (br), 117.1 (br), 120.2, 122.6 (q, JC,F = 273.5 Hz, CF3),
123.2 (q, JC,F = 273.1 Hz, CF3), 124.0, 128.4, 129.2, 130.5, 132.4 (q, JC,F = 33.2 Hz, CCF3),
132.5 (q, JC,F = 33.8 Hz, CCF3), 138.4, 147.4, 154.3 (ArC and C=N), 178.4 (OC(O)) ppm. 19F
NMR (CDCl3, 376.5 MHz, 298 K):  = –63.46 (s, 6F, CF3), –63.02 (s, 12F, CF3) ppm. MS
(ESI+) m/z [ion]: 969 [M – OAc + K]+, 930 [M – OAc]+.
23
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[(6-p-cymene)RuN3{2(N,N)((ArN)2CN(H)Ar}] (Ar = 3,5-(CF3)2C6H3; 5) Complex 3
(100.0 mg, 0.1036 mmol) was stirred with 2 equiv of NaN3 (13.5 mg, 0.207 mmol) in ethanol
(10 mL) in a 25 mL RB flask fitted with a CaCl2 guard tube at RT for 24 h. The volatiles
were removed under vacuum to afford orange solid. The solid was dissolved in CH2Cl2 and
filtered to remove excess of NaN3 and NaCl. Subsequently, CH2Cl2 extract was layered with
n-hexane and the resulting solution stored at RT for 30 h to afford 5 as orange rhombic
shaped crystals. Yield: 93% (93.6 mg, 0.096 mmol). Mp: 152 C (decompn). Anal. Calcd for
C35H21F18N6RuH2O (Mw: 968.62 +18.02): C, 42.61; H, 2.35; N, 8.52. Found: C, 42.92; H,
2.72; N, 8.33. IR (KBr): = 3422 (br, w, NH), 2033 (s, N3), 1550 (m, C=N), 1376 (vs, CF3,
str, asym), 1279 (vs, CF3, str, sym), 1130 (s, CF3, def, asym), 887 (w, CF3, str, sym) cm–1. 1H
NMR (CDCl3, 400 MHz, 298 K):  = 1.25 (d, JH,H = 7.6 Hz, 6H, CH(CH3)2), 2.17 (s, 3H,
CH3), 2.66 (m, 1H, CHMe2), 5.18, 5.37 (each d, 2  2H, JH,H = 6.0 Hz, C6H4), 6.51 (s, 1H,
NH), 7.22 (s, 2H, ArH), 7.26 (s, 1H, ArH), 7.46 (s, 2H, ArH), 7.48 (s, 4H, ArH) ppm.
13C{1H} NMR (CDCl3, 100.5 MHz, 298 K):  = 18.6 (CH3), 22.5 (CH(CH3)2), 31.4
(CHMe2), 79.1, 81.2, 97.6, 101.4 (p-cymene ArCH/ArC), 117.0 (br), 117.3 (br), 120.6, 122.6
(q, JC,F = 273.1 Hz, CF3), 123.1 (q, JC,F = 273.1 Hz, CF3), 123.3, 132.5 (q, JC,F = 33.8 Hz,
19
CCF3), 132.7 (q, JC,F = 33.5 Hz, CCF3), 138.1, 147.3, 153.6 (ArC and C=N) ppm. F NMR
(CDCl3, 376.5 MHz, 298 K):  = –63.54 (s, 6F, CF3), –63.08 (s, 12F, CF3) ppm. MS (ESI+)
m/z [ion]: 969 [M – N3 + K]+, 930 [M – N3]+, 696 [L3H]+.
[(6-p-cymene)RuX{2(N,N)((ArN)2CN(H)Ar}] (Ar = 3,5-(CF3)2C6H3, X = SCN (6) and
X = NCS (7)) Complex 3 (100.0 mg, 0.1036 mmol) was stirred with two equiv of KSCN
(20.1 mg, 0.207 mmol) in methanol (10 mL) in a 25 mL RB flask fitted with a CaCl2 guard
tube at RT for 24 h. Subsequently, the volatiles were removed under vacuum to afford an
orange solid. The solid was dissolved in CH2Cl2 and filtered to remove unreacted KSCN and
KCl. The filtrate was layered with n-hexane and the resulting solution stored at RT for
24
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10.1002/ejic.201900616
European Journal of Inorganic Chemistry
several days to afford a mixture of S-bound isomer, 6 and N-bound isomer, 7 as rhombic
orange crystals. Complexes 6 and 7 were characterized as an admixture in all cases except
SCXRD. Crystals of 6 and 7 were separated by dissolving in CDCl3 and during the course of
this process, a small amount of the latter complex left undissolved due to its lower solubility.
Yield: 92% (94.1 mg, 0.095 mmol). Mp: 158 C (decompn). Anal. Calcd for C36H24F18N4SRu
(Mw: 987.71): C, 43.78; H, 2.45; N, 5.67; S, 3.25. Found: C, 44.11; H, 2.34; N, 6.07; S, 3.48.
IR (KBr): = 3422 (br, w, NH), 2038 (s, SCN/NCS), 1562 (br, w, C=N), 1376 (s, CF3,
str, asym), 1283 (vs, CF3, str, sym), 1128 (s, CF3, def, asym), 881 (w, CF3, str, sym) cm–1.
1
The H NMR spectrum of the sample revealed the presence of 6 and 7 in about 1.00:0.37
ratio respectively as estimated from the integrals of aromatic protons of the p-cymene ring.
1H NMR (CDCl3, 400 MHz, 298 K):  = 1.25, 1.26 (each d, JH,H = 6.8 Hz, 2  6H,
CH(CH3)2, 6 and 7 respectively), 2.18, 2.20 (each s, 2  3H, CH3, 7 and 6 respectively), 2.68
(m, 2  1H, CHMe2, 6 and 7), 5.25, 5.29 (each d, 2  2H, JH,H = 6.0 Hz, C6H4, 7 and 6
respectively), 5.45 (d, 2H, JH,H = 6.4 Hz, C6H4, 7), 5.47 (d, 2H, JH,H = 6.0 Hz, C6H4, 6), 6.66
(s, 2  1H, NH, 6 and 7), 7.10 (s, 2H, ArH, 7), 7.14 (s, 3H, ArH, 6 (2H) and 7 (1H)), 7.16 (s,
1H, ArH, 6), 7.26 (s, 2H, ArH, 6), 7.29 (s, 2H, ArH, 7), 7.47 (s, 4H, ArH, 6), 7.50 (s, 4H,
19
ArH, 7) ppm. The F NMR spectrum revealed the presence of 6 and 7 in about 1.00:0.28
19
ratio. F NMR (CDCl3, 376.5 MHz, 298 K):  = –63.52 (s, 6F, CF3, 7), –63.43 (s, 6F, CF3,
6), –63.03 (s, 12F, CF3, 7), –62.90 (s, 12F, CF3, 6) ppm.
[(6-p-cymene)Ru(NCMe){2(N,N)((ArN)2CN(H)Ar}][SbF6](Ar = 3,5-(CF3)2C6H3; 8)
Complex 3 (100.0 mg, 0.1036 mmol) and AgSbF6 (53.40 mg, 0.1554 mmol) were dispersed
in acetonitrile and the resulting heterogeneous mixture stirred at RT for 12 h in dark in a 25
mL RB flask which was protected with CaCl2 guard tube. The volatiles from the reaction
mixture were removed under vacuum to afford dark orange solid. The solid was extracted
with CH2Cl2 and the unreacted AgSbF6 and AgCl were filtered off. The extract was layered
25
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European Journal of Inorganic Chemistry
with n-hexane and the resulting solution stored at RT for several days to afford 8 as orange
needle shaped crystals suitable for SCXRD. Yield: 85% (106.2 mg, 0.0880 mmol). Mp: 205
C (decompn). Anal. Calcd for C37H24F24N4RuSb3H2O (Mw: 1203.40 + 54.05): C, 35.34; H,
2.40; N, 4.46. Found: C, 35.37; H, 2.23; N, 4.50. IR (KBr): = 3351 (w, NH), 1577 (m,
C=N), 1376 (s, CF3, str, asym), 1284 (s, CF3, str, sym), 1174 (s, CF3, def, asym), 896 (w,
CF3, str, sym), 664 (m, SbF) cm–1. Note: No band was observed for MeCN in the IR
1
spectrum of 8. The H NMR spectrum of 8 revealed the presence of four isomers in about
1.00:0.10:0.45:0.39 ratios as estimated from the integrals of aromatic protons of the p-
cymene ring. 1H NMR (CD3OD, 400 MHz, 298 K):  = 1.21, 1.28 (each d, 2  6H, JH,H = 6.8
Hz, CH(CH3)2, isomers 3 and 4, respectively), 1.30, 1.31 (d, 2  6H, JH,H = 6.8 Hz,
CH(CH3)2, isomers 1 and 2), 2.04 (s, 2  3H, CH3, isomers 1 and 3), 2.07, 2.11 (each s, 2 
3H, CH3, isomers 4 and 2 respectively), 2.16, 2.17, 2.20, 2.55 (each s, 4  3H, CH3CN,
isomers 2, 4, 3 and 1 respectively), 2.67 (m, 3  1H, CHMe2, isomers 24), 2.78 (m, 1H,
CHMe2, isomer 1), 5.21, 5.42 (each d, 2  2H, JH,H = 6.0 Hz, C6H4, isomer 1), 5.49 (s, 1H,
NH, isomer 1), 5.53 (d, 2H, JH,H = 4.0 Hz, C6H4, isomer 2), 5.66 (d, 2H, JH,H = 6.0 Hz, C6H4,
isomer 3), 5.72 (d, 2H, JH,H = 6.4 Hz, C6H4, isomer 4), 5.79 (d, 2H, JH,H = 4.4 Hz, C6H4,
isomer 2), 5.87 (d, 2H, JH,H = 6.0 Hz, C6H4, isomer 3), 5.99 (d, 2H, JH,H = 6.0 Hz, C6H4,
isomer 4), 7.02 (s, 1H, NH, isomer 2), 7.10 (each s, 2  1H, NH, isomers 3 and 4), 7.27 (s, 2
 2H, ArH, isomers 1 and 2), 7.28 (s, 2  1H, ArH, isomers 1 and 2), 7.36 (s, 3H, ArH,
isomer 3), 7.39 (s, 3H, ArH, isomer 4), 7.61 (s, 2H, ArH, isomer 4), 7.64 (s, 2H, ArH, isomer
3), 7.65 (s, 4H, ArH, isomer 4), 7.68 (s, 2  2H, ArH, isomers 1 and 2), 7.78 (s, 4H, ArH,
isomer 3), 7.89 (s, 2  4H, ArH, isomers 1 and 2) ppm. The 19F NMR spectrum of 8 revealed
the presence of three isomers in about 1.00:0.39:0.25 ratios in solution as estimated from the
integrals of CF3 fluorine. 19F NMR (CD3OD, 376.5 MHz, 298 K):  = 64.83, 64.81, 64.77
26
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European Journal of Inorganic Chemistry
(each s, 3  6F, CF3, isomers 13 respectively), 64.54, 64.45, 64.38 (each s, 3  12F,
CF3, isomers 13 respectively) ppm. m (–1 cm2 mol–1, MeCN): 90.6 (10–3 M).
[(6-p-cymene)Ru(N3C2(COOEt)2){2(N,N)((ArN)2CN(H)Ar}] (Ar = 3,5-(CF3)2C6H3;
9) Complex 5 (50.0 mg, 0.051 mmol) was dissolved in CH2Cl2 (5 mL) in a 25 mL RB flask.
To the aforementioned solution, a CH2Cl2 (5 mL) solution of DEAD (26.3 mg, 0.154 mmol)
was slowly added, and stirred at RT for 24 h. The reaction mixture was concentrated under
vacuum to about 2 mL, layered with n-hexane (5 mL) and the resulting solution stored at RT
for 24 h to afford 9 as yellow crystals. Yield: 86% (50.5 mg, 0.044 mmol). Mp: 229 °C
(decompn). Anal. Calcd for C43H34F18N6O4Ru (Mw: 1141.82): C, 45.23; H, 3.00; N, 7.36.
Found: C, 45.12; H, 3.32; N, 7.51. IR (KBr): = 3295 (m, NH), 1731 (s, C=O), 1573 (m,
C=N), 1376 (s, CF3, str, asym), 1275 (s, CF3, str, sym), 1174 (s, CF3, def, asym), 900 (w,
1
CF3, str, sym) cm–1. The H NMR spectrum of 9 revealed the presence of two isomers
(major/minor) in about 1.00:0.05 ratio as estimated from the integrals of aromatic protons of
1
the p-cymene ring. H NMR (CDCl3, 400 MHz, 298 K):  = 1.156 (d, JH,H = 7.2 Hz, 6H,
CH(CH3)2, major), 1.164 (d, JH,H = 6.8 Hz, 6H, CH(CH3)2, minor), 1.243 (t, JH,H = 6.8 Hz, 2
 3H, CH2CH3, major), 1.250 (t, JH,H = 7.4 Hz, 2  3H, CH2CH3, minor), 1.808, 2.128 (each
s, 2  3H, CH3, major and minor respectively), 2.760 (m, 2  1H, CHMe2, major and minor),
4.278, 4.285 (each q, JH,H = 7.2 Hz, 2H, CH2CH3, major and minor respectively), 5.274 (d,
JH,H = 6.0 Hz, 2H, C6H4, minor), 5.426 (d, JH,H = 8.8 Hz, 2H, C6H4, minor), 5.445 (d, JH,H
=
6.4 Hz, 2H, C6H4, major), 5.619 (d, JH,H = 5.2 Hz, 2H, C6H4, major), 7.115 (br, 1H, NH,
minor), 7.176 (s, 1H, NH, major), 7.207 (s, 1H, ArH, major), 7.243 (s, 2H, ArH, major),
7.256 (s, 1H, ArH, minor), 7.268 (s, 2H, ArH, minor), 7.319 (s, 4H, ArH, major), 7.376 (s,
2H, ArH, major), 7.426 (br, 2H, ArH, minor), 7.552 (s, 4H, ArH, minor) ppm. 13C{1H} NMR
(CDCl3, 100.5 MHz, 298 K):  = 14.0 (CH2CH3), 19.0 (CH3), 22.6 (CH(CH3)2), 31.3
(CHMe2), 61.0 (CH2CH3), 81.7, 83.4, 98.5, 103.7 (p-cymene ArCH/ArC), 116.7 (br), 120.4
27
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European Journal of Inorganic Chemistry
(br), 122.7 (q, JC,F = 273.1 Hz, CF3), 123.0 (q, JC,F = 272.8 Hz, CF3), 123.8, 132.2 (q, JC,F
=
33.5 Hz, CCF3), 132.3 (q, JC,F = 33.2 Hz, CCF3), 138.3, 140.1, 147.5, 155.7 (ArC and C=N),
162.5 (OC(O)) ppm. 19F NMR (CDCl3, 376.5 MHz, 298 K):  = –63.46 (s, 6F, CF3), –63.03
(s, 12F, CF3) ppm.
[(6-p-cymene)Ru(PPh2CCPPh2){2(N,N)((ArN)2CNAr}] (Ar = 3,5-(CF3)2C6H3; 10)
Complex 5 (100 mg, 0.102 mmol) was dissolved in CH2Cl2 (10 mL) in a 25 mL RB flask. To
the aforementioned solution, a solution of DPPA (26.3 mg, 0.154 mmol) in CH2Cl2 (5 mL)
was slowly added, and stirred at RT for 24 h. The volatiles were removed under vacuum to
afford an orange solid which was dissolved in n-hexane and stored at RT for four days to
afford 10 as orange crystals. Yield: 87% (118.6 mg, 0.089 mmol). Mp: 178 °C. Anal. Calcd
for C61H43F18N3P2Ru (Mw: 1023.00): C, 55.38; H, 3.28; N, 3.18. Found: C, 55.70; H, 3.65; N,
3.52. IR (KBr): = 1536 (m, C=N), 1373 (s, CF3, str, asym), 1280 (s, CF3, str, sym), 1126
1
(m, CF3, def, asym), 909 (w, CF3, str, sym) cm–1. H NMR (CDCl3, 400 MHz, 298 K):  =
1.05 (d, JH,H = 6.8 Hz, 6H, CH(CH3)2), 1.75 (s, 3H, CH3), 2.34 (m, 1H, CHMe2), 4.96 (d, JH,H
= 5.6 Hz, 2H, C6H4), 5.31 (d, JH,H = 6.0 Hz, 2H, C6H4), 6.73 (s, 2H, ArH), 6.82 (s, 1H, ArH),
7.09 (s, 2H, ArH), 7.27 (m, 3H, ArH), 7.347.40 (m, 8H, ArH), 7.537.65 (m, 13H, ArH)
ppm. 13C{1H} NMR (CDCl3, 100.5 MHz, 298 K):  = 18.28 (CH3), 22.51 (CH(CH3)2), 30.97
(CHMe2), 86.61, 88.62, 88.66 (p-cymene ArCH/ArC), 99.68, 100.48 (each d, JC,P = 5.7, 4.8
Hz respectively, Ph2PCCPPh2), 102.84, 111.19 (br), 111.95 (br), 112.71, 113.04, 113.47,
113.55, 121.25, 121.69, 123.78 (q, JC,F = 272.7 Hz, CF3), 123.83 (q, JC,F = 272.7 Hz, CF3),
125.16 (br), 127.88 (br), 128.92, 129.03, 129.10, 129.18, 130.07, 130.68 (q, JC,F = 32.6 Hz,
CCF3), 130.70, 131.08 (q, JC,F = 33.6 Hz, CCF3), 131.52, 131.99, 132.11, 133.06, 133.27,
133.44, 133.50, 149.2, 152.0, 161.6 (ArC and C=N) ppm. 19F NMR (CDCl3, 376.5 MHz, 298
31
K):  = –63.03 (s, 6F, CF3), –62.72 (s, 12F, CF3) ppm. P{1H} NMR (CDCl3, 161.8 MHz,
298 K):  = 18.05 (s, 1P, uncoordinated), 31.34 (s, 1P, coordinated) ppm.
28
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10.1002/ejic.201900616
European Journal of Inorganic Chemistry
Procedure forRuAAC A mixture of phenylacetylene (102.2 mg, 1.000 mmol), 4-tolyl azide
(66.6 mg, 0.500 mmol) was dissolved in CH2Cl2 (5.0 mL) in a 10 mL RB flask. To the
aforementioned flask, 1 mol % of the catalyst was added and stirred at RT for 30 min.
Subsequently, 10 mol % of AgOAc (83.2 mg, 0.05 mmol) was added to the flask and stirred
at RT for 24 h under dark. The reaction mixture was kept at RT for several days to afford 23
as colorless crystals suitable for SCXRD. The % conversion and the relative ratio of 23 and
1
24 in the reaction mixture were estimated by H NMR spectroscopy. The reaction mixture
was subjected to column chromatography on silica gel using ethyl acetate/n-hexane mixture
(5/95, v/v) as eluent to afford 23 for the following data. Yield: 62% (73.0 mg, 0.31 mmol).
1
Characterization Data of 23 Mp: 167.0 °C (Mp 165.0167 °C[36]). H NMR (CDCl3, 400
MHz, 298 K):  = 2.43 (s, 3H, CH3), 7.327.38 (m, 3H, ArH), 7.46 (t, JH,H = 7.4 Hz, 2H,
ArH), 7.66 (d, JH,H = 8.4 Hz, 2H, ArH), 7.907.92 (m, 2H, ArH), 8.16 (s, 1H, ArH, triazole
ring proton) ppm. 13C{1H} NMR (CDCl3, 100.5 MHz, 298 K):  = 21.2 (CH3), 117.8, 120.6,
1
13
126.0, 128.5, 129.0, 130.4, 130.5, 134.9, 139.0, 148.4 (ArCH/ArC) ppm. H and C{1H}
NMR data reported herein closely matched with those reported in the literature.[47]
Supporting Information
General considerations, details pertinent to data collections, structure solution, and
refinements of the crystallographically characterized compounds are presented in Tables
S1S3. Possible solution species of compound such as 1, non-covalent interactions in the
crystal lattice of 4, 5MeOH, 6 and 7CHCl3 and molecular structure of 23 are illustrated in
Figures S2S6 in the SI. Structural data in CIF format is available as the SI. CCDC
18960821896092 contain the supplementary crystallographic data for this article. These
data can be obtained free of charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
29
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