Novel bis(β-diketonato)diorganotin(IV) derivatives containing bulky 4-acyl-5-pyrazolonato ligands: Influence of the steric hindrance of the acyl moiety on the solid state structures of tin complexes and their behaviour in solution

Article abstract of DOI:10.1016/j.ica.2010.12.008

New (Q)₂SnR₂ derivatives (HQ in general; in detail: HQCHPh2 = 4-diphenylacetyl-3-methyl-1-phenyl-5-pyrazolone; HQ^Bn = 3-methyl-1-phenyl-4-phenylacetyl-5-pyrazolone; HQ^naph = 3-methyl-4-naphthoyl-1-phenyl-5-pyraz

Full text of DOI:10.1016/j.ica.2010.12.008

Inorganica Chimica Acta 367 (2011) 73–84
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Inorganica Chimica Acta
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Novel bis(b-diketonato)diorganotin(IV) derivatives containing bulky 4-acyl-5-
pyrazolonato ligands: Influence of the steric hindrance of the acyl moiety
on the solid state structures of tin complexes and their behaviour in solution
b
c
d,
b
Francesco Caruso a, , Corrado Di Nicola , John V. Hanna , Fabio Marchetti , Claudio Pettinari ,
⇑
⇑
Riccardo Pettinari b, Miriam Rossi e, Gregory J. Rees c, Brian W. Skelton f, Allan H. White f
a Istituto di Chimica Biomolecolare, c/o University of Rome ‘‘La Sapienza’’, Istituto Chimico, Piazzale Aldo Moro 5, 00185 Rome, Italy
b School of Pharmacy, Università degli Studi, via S. Agostino 1, 62032 Camerino, MC, Italy
c Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
d School of Science and Technology, Università degli Studi di Camerino, via S. Agostino 1, 62032 Camerino, MC, Italy
e Vassar College, Department of Chemistry, Poughkeepsie, NY 12601, USA
f Chemistry M313, School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, Crawley, WA 6009, Australia
a r t i c l e i n f o
a b s t r a c t
New (Q)2SnR2 derivatives (HQ in general; in detail: HQCHPh = 4-diphenylacetyl-3-methyl-1-phenyl-5-pyr-
azolone; HQBn = 3-methyl-1-phenyl-4-phenylacetyl-5-pyrazolone; HQnaph = 3-methyl-4-naphthoyl-1-
phenyl-5-pyrazolone; R = CH3, C2H5, C6H11, n- and t-C4H9, C6H5,) have been synthesised and characterised
2
Article history:
Received 25 August 2010
Received in revised form 15 November 2010
Accepted 1 December 2010
Available online 9 December 2010
by analytical and spectral techniques. Variable temperature NMR studies of ðQCHPh Þ SnR2 derivatives
2
2
(R = CH3 and C2H5) in chlorohydrocarbon solvents indicate a fluxional behaviour, with rapid interconver-
sion between six- and five-coordinate species, the latter containing a bidentate acylpyrazolonate and a
Keywords:
Diorganotin(IV)
4-Acyl-5-pyrazolones
NMR, Crystal structures
Solid state 119Sn MAS NMR
monodentate one. The X-ray crystal structures of the diorganotin(IV) derivatives ðQCHPh Þ SnMe2,
2
2
ðQCHPh Þ SnEt2, (QBn)2SnMe2 and ðQnaphÞ2SnBun2, inclusive of a representative of each Qx family, show the
2
2
metal centres in a skewed trans octahedral configuration. The 4-acyl moiety of the b-diketonate donor
exerts a steric effect which is correlated to structural behaviour in the solid and solution state. A solid state
119Sn CPMAS NMR study of the (QBn)2SnR2 (R = CH3, C2H5, t-C4H9 and C6H5) complexes shows a marked
deshielding effect and upfield movement of the 119Sn isotropic chemical shift (diso) through this series.
The 119Sn chemical shift spans (
although the markedly reduced
X
X
) are the largest reported for directly oxo-coordinated Sn(IV) systems,
value for the (QBn)2SnPh2 complex may be indicative of a cis octahedral
coordination, in contrast to the trans octahedral coordination characterising the other complexes of this
suite.
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
active, the general mechanism involving pre-dissociation of the
bidentate ligand as a crucial step in the formation of an Sn–DNA
Six-coordinated tin(IV) and organotin(IV) complexes of O,O0-
bidentate donors which can form six-membered chelate rings,
with cis or trans octahedral configurations, are prominent in the lit-
erature [1]. Current interest arises from reports indicating tin(IV)
complex activity against a wide variety of viruses, bacteria and tu-
mours [2]. Much work has been done to correlate the geometries of
organotin(IV) adducts of the type [R2SnX2L2] (R = alkyl or aryl
group; X = halide; L = N- or O-donor ligand) with their effective-
ness as antitumour agents [3]. Those with shorter Sn–L bond dis-
tances and trans-diethyl or cis-dichloro groups are the more
complex [4]. Several structural studies are available on diorgano-
[5] and dihalotin(IV) [6] derivatives containing b-diketonates and
monothio-b-diketonates showing that alkyl groups on the tin gen-
erally occupy trans positions [5] whereas the halides adopt cis posi-
tions [5c,6], the latter also exhibiting high in vivo activity against
some tumours [6c]. We are currently interested in tin complexes
of 4-acyl-5-pyrazolones, a family of asymmetric b-diketonates
having the chelating moiety fused to a pyrazole ring; these are
widely used as pigments for dyes [7], as metal extractants from
acidic solutions [8], and for trace element spectrophotometric
determinations [9]. Our strategy in this research has been to syn-
thesise new donors with different substituents R1, R2 and R3
(Scheme 1), so as to obtain variations in electronic and steric
features of the ligands, and, consequently, in the properties of their
metal derivatives. Structural and spectroscopic (IR, NMR and
⇑
Corresponding authors. Tel.: +39 (0)737 402217; fax: +39 (0)737 637345
(F. Marchetti).
E-mail addresses: fabio.marchetti@unicam.it (F. Caruso), caruso@vassar.edu
(F. Marchetti).
0020-1693/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2010.12.008

74
F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
R3
R2
Me
Me
Me
O
O
O
O
N
N
N
N
HO
HO
HO
HO
N
N
N
N
R1
General structure of HQ
HQCHPh2
HQBn
HQnaph
Scheme 1.
Mössbauer) data have shown that dialkyltin(IV) complexes gener-
ally adopt highly distorted trans octahedral geometries, with two
sets of Sn–O bond distances, and C–Sn–C angles less than 160°
[10]. By contrast, diaryltin(IV) complexes can exist in the solid
and in solution states as mixtures of cis or trans isomers; for these,
X-ray structures show less distorted C–Sn–C angles (in the range of
165–175°), and Mössbauer data also indicate the existence in the
solid state of isomers for which those angles lie in the range of
110–120° [11]. The metal–ligand interactions are generally weaker
than those found for analogous acetylacetonato/tin(IV) derivatives,
an interesting feature in view of their potential bio-activity. In par-
ticular, the oxygen atom of the acyl moiety [O(acyl) = Oa] is always
less tightly bound than that at the 5-position of the pyrazole
[O(pyrazolonato) = Op]; this feature is observed also in the case
of 4-acyl-5-pyrazolonato derivatives of lead [12], uranium [13],
copper [14] and mercury [15]. In a previous paper, we showed that
the use of R3 = methyl considerably enhances the solubility in
water of the metal derivatives, a useful property in view of possible
biological applications [10g]. In this work, we report the synthesis
and characterisation of a series of diorganotin(IV) complexes with
new functionalized 4-acyl-5-pyrazolones (Scheme 1), having in the
R3 position a more sterically hindered group relative to the donors
previously employed, with the goal of modifying the structural
behaviour of the corresponding tin(IV) derivatives, both in the so-
lid state and in solution. The crystal structures of four derivatives,
representative of the R3 = CHPh2, Bn, and naphthyl families, are re-
ported together with variable temperature NMR and solid state
119Sn NMR studies.
All derivatives 1–13 are air and moisture stable solids, with
sharp melting points, insoluble in water, alcohols, diethyl ether,
and aliphatic hydrocarbons, sparingly soluble in aromatic solvents
and soluble in acetone, DMSO and chlorohydrocarbon solvents,
where they show a monomeric nature or, at least in dilute solu-
tions, some limited partial dissociation, the ratio between experi-
mental and theoretical molecular weight being in the range
0.70–0.90. They are non-electrolytes in the same solvents.
IR data show shifts to lower frequencies of
to 1600 cmꢀ1) and the disappearance of the broad band at
2700 cmꢀ1 due to intramolecular (O–H. . .O) of the ligand upon
m(C@O) (from 1640
m
coordination, thus indicating chelation of the donor through both
carbonyl groups of the monoanionic deprotonated form. In the
far-IR region the presence of both
ms(Sn–C) and mas(Sn–C), and of
several (Sn–O) bands (Fig. 1) is consistent with distortion from
m
octahedral geometry about the tin atom, as in fact observed in
the crystal structures of derivative ðQCHPh Þ SnMe2, Et2 and
2
2
ðQnaphÞ2SnBun (see below; structural section).
2
The broad signals at ca. 12.0 ppm due to enolic protons of the
proligands in the 1H NMR spectra disappear upon coordination,
in accordance with coordination of the donor in monoanionic form.
The integration of the signals due to the ligand and to the organo-
tin moiety supports the 2:1 ligand to metal ratio proposed. At room
temperature and in chlorohydrocarbon solution the dimethyl-
tin(IV) derivative 1 shows unique sets of resonances for the hydro-
gen atoms in the QCHPh ligands and those of the organic groups on
2
the tin atom, but on lowering the temperature the resonance for
each chemically and magnetically equivalent group of H splits into
2
two peaks (Fig. 2). The J(Sn–H) of the two different resonances for
the SnMe2 moiety (98.3 and 70.5 Hz) are consistent with the pres-
ence of two different isomers. From the Lockhart relationship [16],
values of 159° and 120° for the C–Sn–C angle are obtained, typical
of a trans skewed octahedral species and of a trigonal bipyramidal
species, respectively. A variable temperature 1H NMR study of the
diethyltin(IV) derivative 2 shows a similar behaviour. Moreover,
2. Results and discussion
Derivatives 1–13 have been synthesised from reaction between
the donor HQ and the acceptor SnR2Cl2 in methanol in the presence
of KOH base (Scheme 2).
R3
R3
R3
R
O
O
O
O
Me
O
Me
Me
Sn
R
+ 2 KOH + R2SnCl2
2
N
N
N
OH
methanol
-2 KCl
N
N
N
1-13
1, R3 = CHPh2, R = Me
2, R3 = CHPh2, R = Et
3, R3 = CHPh2, R = Cy
4, R3 = CHPh2, R = But
5, R3 = CHPh2, R = Ph
11, R3 = 2-naphthyl, R = Me
12, R3 = 2-naphthyl, R = Bun
13, R3 = 2-naphthyl, R = Ph
6, R3 = CH2Ph, R = Me
7, R3 = CH2Ph, R = Et
8, R3 = CH2Ph, R = Cy
9, R3 = CH2Ph, R = But
10, R3 = CH2Ph, R = Ph
Scheme 2.

F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
75
Fig. 1. Far-IR spectra of derivatives 1–4.
room temperature studies of derivatives 3 and 4 display quite
broad resonances. 119Sn NMR spectra of 1 and 2 show a progressive
broadening on cooling from 293 to 223 K.
179° and 176° (angles calculated from this relationship have a
standard error calculated as l2°). By contrast, 13C NMR spectra
of di-tert-butyltin(IV) derivatives 4 and 8, and of diphenyltin(IV)
derivatives 5, 10 and 13 show broad resonances, in accordance
with fluxionality between different geometrical isomers present
in solution.
This seems to support the view that the bis(b-diketonato)dial-
kyltin(IV) six-coordinate derivatives 1–4 of QCHPh exist as mix-
2
tures of isomers in chlorohydrocarbon solution (Scheme 3), this
behaviour being observed here for the first time. In fact, for all pre-
viously studied acylpyrazolonates only one set of resonances (also
at ꢀ90 °C) was found. This feature can be explained assuming (a) a
very fast fluxionality about the tin, (b) the presence of only one
trans isomer in solution (more likely), (c) formation of a neutral
five-coordinate species, or (d) formation of an ionic four-coordi-
nate tin complex from partial dissociation of one or both carbonyl
arms of a Q ligand. The proton NMR spectra of the alkyltin(IV)
derivatives 6–8 and 11–12 of QBn and Qnaph display unique sets
of sharp resonances both at room and low temperatures, thus indi-
cating the presence in solution of only one isomeric species.
In 13C NMR spectra of dialkyltin(IV) derivatives 1–3, 6–8 and
10–11 the expected nJ(Sn–C) coupling constants have been observed,
values being in the range of typical trans-octahedral compounds.
In fact, by applying the empirical relation h(C–Sn–
C) = 0.178 ꢁ |1J(119Sn–13C)| + 14.74, derived by Howard for octahe-
dral dialkyltin complexes of type R2SnCh2 (R = alkyl, Ch = bidentate
ligand) [17], the calculated C–Sn–C angle for 1, 6 and 11 are 172°,
In our derivatives, the existence of a mixture of isomers in solu-
tion may be attributed to the effect of steric hindrance about the
acyl moiety in the ligand QCHPh , which should destabilize one
2
Sn–O bond. The increase of steric hindrance in the organic groups
bonded to the tin atom generates an increase in the 119Sn chemical
shift toward lower frequencies. The effect is approximately addi-
tive, as shown in Fig. 3 [10b,c,f–h,11], presumably as consequence
of increased electro-releasing properties on going from the methyl
group to the t-butyl group, and also in accordance with crystallo-
graphic data, as seen in our previous work [10g,11].
The diphenyltin derivatives 5, 10 and 13, having bulky electron-
releasing groups bound to the tin atom, show broad resonances in
the 1H NMR spectra and two sets of broad resonances in the 119Sn
NMR spectra, presumably due to trans-isomers (syn- and anti-con-
figurations). In addition, derivative 13 also shows a resonance at
ꢀ740 ppm, falling in a range typical of cis-dihalotin(IV) derivatives
[10a,18]. We hypothesise that the large steric hindrance of the
naphthyl groups in Qnaph ligands might require the phenyl groups

76
F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
Fig. 2. Variable temperature 1H NMR spectra for derivative 1.
CH
N
CH
N
Me
CH
O
H3C
O
O
O
O
Me
CH
N
H3C
CH3
O
Sn
O
N
CH3
N
N
Sn
Me
O
N
Me
N
Scheme 3.
on the tin atom to assume a cis-configuration in order to reduce
crowding around the metal (Scheme 4).
0
-50
Q = QCHPh2
Q = QBn
2.1. Structural studies
-100
-150
-200
-250
-300
-350
-400
-450
-500
The results of the single crystal X-ray studies of [ðQCHPh Þ SnR2]
2
2
(1: R = Me, 2: R = Et), [(QBn)2SnMe2] (6) and [ðQnaphÞ2SnBun2] (12),
are consistent with a single molecule, devoid of crystallographic
symmetry, comprising the asymmetric unit of each structure. The
tin atoms are six-coordinate, the alkyl groups are trans and the or-
ganic ligands behave as O,O0-bidentates (Figs. 4–7 and Table 1).
Coordination geometries are similar to those of other such trans
[Q2SnR2] complexes [10]. The present complexes are of particular
interest, however, due to their bulky Q substituents: their impact
on the molecular conformation, suggest (Figs. 4 and 5 and Table 1)
the orientations of the pairs of the groups in each complex are such
as to impose the adoption of approximated 2-fold symmetry for
1
6
2
3
8
7
4
9
(Q)2SnMe2
(Q)2SnEt2
(Q)2SnCy2
(Q)2SnBut2
Fig. 3. Influence of steric bulk of the R groups on the 119Sn NMR spectra of (Q)2SnR2
derivatives.
complexes 1 and 2, having ligands QCHPh . This 2-fold axis is not
2

F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
77
O
O
N
N
H3C
O
O
O
O
O
O
O
O
Sn
H3C
CH3
H3C
Sn
Sn
O
N
CH3
N
N
N
N
N
O
N
N
N
CH3
N
trans-syn
trans-anti
cis
Scheme 4.
Fig. 4. Molecular projection of bis(4-diphenylacetyl-3-methyl-1-phenyl-pyrazolon-5-ato)diethyltin(IV) (2) showing coordination sphere labels (H atoms omitted). The
torsion angles between Ph and the attached pyrazole rings are 10.6° (C15–N11–C111–C112) and 32.7° (C25–N21–C211–C212). Labelling is consistent with those in Figs. 5–7.
retained at the periphery of the benzyl and naphthyl complexes 6
and 12 (Fig. 7).
are syn. The dihedral angles between the phenyl rings and their
attached pyrazole rings are given in Table 1, as their associated tor-
sion angles. These differ widely between ligands, ranging from
3.6(8)° to ꢀ47.4(7)° in complex 12, susceptible to packing forces
as seen in related compounds [11]. The ligand bite angle in Table 1
is within the range 80.4–82.5° similar to related compounds [11].
As mentioned earlier the complex with R1 = p-CF3–Ph shows the
dramatic influence of the repulsion between both R1 ligands
resulting from the fluorine atoms on its structure by stabilizing
an anomalous centrosymmetric arrangement. This is due to the
small O(pyrazolonate)–Sn–O0(pyrazolonate) bond angle that makes
both R1 groups close enough for repulsion. In the present case, the
large R3 groups may establish a similar hindrance, although, the
large space available to the acyl groups, because of a wide
O(acyl)–Sn–O0(acyl) angle, may still accommodate groups as large
as the Ph2C and naphthyl in the present compounds. The crystal
structures show no unexpected geometrical features. Thus, for
instance, the C–Sn–C0 bond angles in the four derivatives
range from 153.0(2)° to 160.00(9)° about the median value of
156° for the corresponding range 150–173° found in the literature
and so we conclude that the presence of the large acyl moieties
The crystal structures of 1, 2, 6, and 12, Figs. 4–7, show a
skewed trapezoidal bipyramidal arrangement about the metal
atom. This is characterised by short Sn–O(pyrazolonato) and long
Sn–O(acyl) bond lengths; e.g. in the ethyl complex (2) they are
[2.122(6) and 2.148(5) Å] and [2.324(5), 2.311(6) Å], respectively.
The trend is similar for the other derivatives as seen in Table 1.
In addition, the longer Sn–O(acyl) bonds form a O(acyl)–Sn–
O0(acyl) bond angle much wider than O(pyrazolonate)–Sn–O0(pyra-
zolonate)– 116.5(2)° and 82.3(2)°, respectively, in the ethyl
complex. Both carbon atoms bound to the tin tend to occupy the
space left by the two O(acyl) moieties so that a wider O(acyl)–
Sn–O0(acyl) bond angle corresponds to a smaller C–Sn–C0 bond
angle. This trend is generally seen in the literature of 4-acyl-5-pyr-
azolonato-diorganotin compounds, the only exceptions being
bis(4-benzoyl-3-methyl-1-(4-(trifluoromethyl)phenyl)-pyrazolon-
5-ato)-dimethyl-tin(IV) [19] and cis-bis((l2-1,4-bis(3-methyl-5-
oxy-1-phenyl-1H-pyrazol-4-yl)butane-1,4-dione)-di-n-butyl-tin(IV))
[20], which display regular octahedral arrangements with the li-
gand anti, in contrast to those of the previous compounds that

78
F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
Fig. 5. Molecular projection of bis(4-diphenylacetyl-3-methyl-1-phenyl-pyrazolon-5-ato)dimethyltin(IV) (1) down the C–Sn–C ‘line’, showing the approximate 2-fold axis
through the metal in the plane of the page.
Fig. 6. Molecular projection of bis(3-methyl-4-naphthoyl-1-phenyl-pyrazolon-5-ato)di-n-butyltin(IV) (12).
does not modify substantially the coordination sphere in the solid
state.
½ðQBnÞ2SnBut2ꢂ (9) and [(QBn)2SnPh2] (10) are shown in Fig. 8, and the
associated 119Sn chemical shift tensor parameters elucidated from
these data are summarised in Table 2. For each system 119Sn MAS
NMR data have been acquired at MAS frequencies of 4 and 11 kHz to
facilitate an accurate determination of the fundamental shift parame-
ters diso,mas, d11, d22 and d33, and subsequently the chemical shift tensor
2.2. 119Sn solid state NMR section
The 119Sn CPMAS NMR data for the bis(3-methyl-1-phenyl-4-phen-
ylacetylpyrazolon-5-ato) series [(QBn)2SnMe2] (6), [(QBn)2Sn-Et2] (7),
descriptors such as span
X, skew j, anisotropy Dd, and asymmetry g.

F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
79
although the quasi-planar O,O0-bidentate environment and the alkyl/
aromatic trans-substitution invokes an approximate 2-fold symmetry.
This is reflected by the moderately high
j values (or moderately low g
values) suggesting approximate axial symmetry. From Table 2 the
measured isotropic chemical shifts diso,mas for the series 6, 7, 9 and
10 exhibit a monotonic decrease from d ꢀ316 ppm (for 6) to d
ꢀ474 ppm (for 10), commensurate with the decreasing electron dona-
tion (or increased deshielding) capability of the trans-organic substit-
uents, considering that the 119Sn nucleus possesses a negative
gyromagnetic ratio (
have been previously reported for Sn-tris(tropolonato) [21] and Sn-
c
= ꢀ10.0138 ꢁ 107 rad Tꢀ1 sꢀ1). Similar trends
oxydiacetate [22] suites of complexes. The spans for complexes 6, 7
and 9 from Table 2 of up to ꢃ1430 ppm represent the largest
X values
for directly oxo-coordinated Sn(IV) systems [21–25], but are much
smaller than reported values for 2-coordinate Sn(II) systems such as
[SnC6H3-2,6-Trip2] where
X can exceed 4000 ppm [26]. For 10 a much
reduced value of 605 ppm is reported (see Table 2), which is less
X
than half the magnitude of that measured in complexes 6, 7 and 9. This
observation could be attributed to (i) fast phenyl rotation (on the time-
scale of the NMR experiment) where tensor elements d11 and d33 can
become partially averaged, or (ii) the phenyl derivative may adopt a
cis octahedral environment in contrast to the trans octahedral arrange-
ment that characterises the other complexes of this suite.
Fig. 7. Molecular projection of bis(3-methyl-1-phenyl-4-phenylacetyl-5-pyrazo-
lon-5-ato)di-methyltin(IV) (6).
3. Conclusions
Several diorganotin(IV) derivatives containing sterically
hindered 4-acyl-5-pyrazolonate ligands have been reported and
fully characterised by a combination of solid state and solutions
techniques. Solution NMR data indicate that bulky substituents
on the acyl moiety of chelating ligands, in conjunction with
tert-butyl or phenyl groups on tin, play a key role in the forma-
From Table 2 it can be observed that an excellent agreement exists be-
tween the measured isotropic chemical shift (diso,mas) and the calcu-
lated isotropic chemical shift (diso,calc), thus suggesting that the
nominated positions of d11, d22 and d33 from each 119Sn CPMAS spec-
trum have been determined accurately. These data are consistent with
the crystallographic description of 6 above where the structural dispo-
sition of the six-coordinate tin environment (skewed trapezoidal bipy-
ramidal arrangement) provides no apparent formal point symmetry,
tion of isomeric species. In the case of very bulky QCHPh ligand,
2
six-coordinate tin species also have been observed to exist in
equilibrium with five-coordinate species, likely arising from the
Table 1
naph
Metal atom coordination geometries ½ðQCHPh Þ SnMe2; Et2ꢂ (1, 2), [(QBn)2SnMe2] (6) and ½ðQ
Þ2SnBun2ꢂ (12) (Counterpart values for (2, 6, 12) follow those for (1).)
2
2
Atoms
Parameter
Atoms
Parameter
Distance (Å)
Sn–C(10)
Sn–O(15)
Sn–O(141)
2.106(2), 2.11(1), 2.095(2), 2.117(5)
2.129(1), 2.122(6), 2.121(2), 2.133(3)
2.306(1), 2.324(5), 2.325(2), 2.398(3)
Sn–C(20)
Sn–O(25)
Sn–O(241)
2.099(2), 2.111(9), 2.097(2), 2.115(6)
2.135(1), 2.148(5), 2.126(2), 2.097(3)
2.278(1), 2.311(6), 2.276(2), 2.383(3)
Angles (°)
C(10)–Sn–C(20)
O(15)–Sn–O(25)
O(15)–Sn–O(141)
O(15)–Sn–O(241)
C(10)–Sn–O(15)
C(20)–Sn–O(15)
C(10)–Sn–O(141)
C(20)–Sn–O(141)
160.00(9), 154.1(1), 157.68(10) 153.0(2)
83.96(5), 82.3(2), 80.03(6), 74.9(2)
80.58(2), 80.5(2), 82.51(6), 80.4(1)
165.71(5), 162.9(2), 162.56(6), 154.1(1)
96.64(7), 99.3(3), 99.86(9), 98.8(2)
98.46(7), 99.4(3), 96.11(9), 102.1(2)
85.97(7), 81.0(3), 82.66(8), 86.2(2)
83.66(7), 84.6(3), 84.07(9), 80.8(2)
O(141)–Sn–O(241)
O(25)–Sn–O(241)
O(25)–Sn–O(141)
C(10)–Sn–O(25)
C(20)–Sn–O(25)
C(10)–Sn–O(241)
C(20)–Sn–O(241)
113.66(5), 116.5(2), 114.74(6), 125.4(1)
81.84(2), 80.7(2), 82.81(6), 79.8(1)
164.42(5), 162.8(2), 162.40(6), 154.5(1)
97.74(7), 101.4(3), 98.09(8), 103.4(2)
96.82(7), 98.7(3), 99.96(9), 98.1(2)
83.72(7), 84.6(3), 85.58(9), 82.0(2)
84.86(7), 82.8(3), 83.78(9), 86.5(2)
Interplanar dihedral angles (°)
C3O2(1)/C3O2(2)
C3O2(1)/C3N2(1)
C6(11)/C3N2(1)
C6(15)/C3O2(1)
C6(16)/C3O2(1)
11.40(6), 7.5(3), 8.57(6), 7.8(3)
5.84(7), 5.0 (3), 2.25(7), 2.0(2)
5.96(8), 6.8(3), 39.91(8), 46.7(2)
79.84(7), 82.8(4), 86.78(8), –
69.06(8), 77.4(4), –
C3O2(2)/C3N2(2)
C6(21)/C3N2(2)
C6(25)/C3O2(2)
C6(26)/C3O2(2)
6.17(7), 4.9(3), 1.99(7), 5.8(2)
39.42(8), 33.0(3), 5.02(8), 2.4(2)
84.44(6), 89.0(3), 85.97(8), –
76.40(7), 79.4(3), –
Ph-pyrazole and CHPh2 torsion angles (°) (carbon atoms denoted by number only)
15–N(11)–111–112
O(141)–141–142–151
141–142–151–152
O(141)–141–142–161
141–142–161–162
5.9(3), 11(1), 39.7(3), ꢀ47.4(7)
57.5(2), 50.6(9), ꢀ54.7(2)
ꢀ73.3(2), ꢀ71.6(9), ꢀ70.4(2)
ꢀ66.6(2), ꢀ74.6(9)
25–N(21)–211–212
O(241)–241–242–251
241–242–251–252
O(241)–241–242–261
241–242–261–262
41.7(3), 33(1), ꢀ2.8(3), 3.6(8)
44.2(2), 40.1(9), 101.3(2)
ꢀ77.6(2), ꢀ80.4(9), ꢀ21.4(3)
ꢀ82.0(2), ꢀ85.6(9)
ꢀ2.8(3), ꢀ12.9(11)
14.3(3), 13.6(11)
The Sn atom lies 0.844(2), 0.609(2) Å out of the C3O2 planes in (1), 0.386(9), 0.188(7) in (2), 0.289(3), 0.333(3) in (6), 0.238(7), 0.085(7) Å in (12). In (12), the naphthyl planes
lie at 88.5(2), 65.5(2)° to their associated C3O2 planes.

80
F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
Fig. 8. 119Sn CPMAS NMR spectra of the bis(3-methyl-1-phenyl-4-phenylacetylpyrazolon-5-ato) complexes [(QBn)2SnMe2] 6, (a), [(QBn)2SnEt2] 7, (b), ½ðQBnÞ2SnBut 2ꢂ 9, (c) and
[(QBn)2SnPh2] 10, (d).
Table 2
119Sn isotropic chemical shifts and chemical shift tensor parameters measured from the 119Sn CPMAS NMR data of Fig. 8.
a
b
Sn complex
diso,mas (ppm)
D
diso,calc (ppm)
d11 (ppm)
d22 (ppm)
d33 (ppm)
Xc (ppm)
jc
D
dd (ppm)
gd
( 2)
( 20)
( 20)
( 20)
( 20)
( 20)
( 0.005)
( 20)
( 0.005)
[(QBn)2SnMe2] (6)
[(QBn)2SnEt2] (7)
ꢀ316
ꢀ346
ꢀ450
ꢀ314
ꢀ345
ꢀ434
220
195
34
48
ꢀ1209
ꢀ1184
ꢀ1181
1429
1379
1215
0.77
0.65
0.69
ꢀ1343
ꢀ1258
ꢀ1120
0.19
0.23
0.25
ꢀ47
½ðQBnÞ2SnBut2ꢂ (9)
ꢀ156
[(QBn)2SnPh2] (10)
ꢀ474
ꢀ474
ꢀ205
ꢀ407
ꢀ810
605
0.33
ꢀ504
0.60
a
b
c
Measured directly from 119Sn MAS data.
Determined from the tensorial positions via the relationship diso,calc = (d11 + d22 + d33)/3.
Herzfeld–Berger shift convention: d11 P d22 P d33 (tensorial representation not shown above), diso = (d11 + d22 + d33)/3,
P ꢀ1).
Haeberlen shift convention: |d33 ꢀ diso| P |d11 ꢀ diso| P |d22 ꢀ diso
3/2(d33 ꢀ diso), d = (d22 ꢀ d11)/(d33 ꢀ diso) (1 P d P 0).
X
= (d11 ꢀ d33),
j
= 3(d22 ꢀ diso)/ (d11 ꢀ d33
)
(1 P
j
d
|
(tensorial representation shown above), diso = (d11 + d22 + d33)/3, D
d = d33 ꢀ 1/2(d11 + d22) =
g
g
breaking of one Sn–O bond. Moreover, the diphenyltin(IV)
derivative of Qnaph is likely to exist in solution as a mixture of
trans and cis isomers. Solid state 119Sn NMR data are in accor-
dance with a general trans-arrangement of the organyl groups
on tin, as also confirmed by the X-ray structural determination
of two dimethyltin(IV), one diethyltin(IV) and one di-n-butyl-
tin(IV) derivative. However in the case of the diphenyltin(IV)
derivative of QBn a much reduced
X value seems to indicate
fast phenyl rotation or even a cis-arrangement of the phenyl
groups.

F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
81
immediately. The mixture was stirred overnight and the precipi-
tate was then filtered off, washed with methanol (ca. 10 ml) and
dried under reduced pressure at room temperature. This was
recrystallised from chloroform/methanol. Yield 57%. Mp 177–
180 °C. Elemental analyses Calc for C50H44N4O4Sn: C, 68.0; H, 5.0;
N, 6.3. Found: C, 67.7; H, 5.2; N, 6.4%. F.w. = 884; M.w. = 633
4. Experimental section
4.1. General comments
The tin(IV) and organotin(IV) halides were purchased from Alfa
(Karlsruhe) and Aldrich (Milwaukee) and used as received. The
samples for microanalyses were dried in vacuo to constant weight
(20 °C, ca. 0.1 Torr). Elemental analyses (C, H, N) were performed
in-house with a Fisons Instruments 1108 CHNS-O Elemental
Analyzer. Molecular weight determinations were performed with
a Knauer membrane osmometer. IR spectra were recorded from
4000 to 100 cmꢀ1 with a Perkin Elmer System 2000 FT-IR instru-
ment. 1H, 19F and 119Sn NMR spectra were recorded on a VXR-
300 Varian spectrometer operating at room temperature
(300 MHz for 1H, 282.2 MHz for 19F and 111.9 MHz for 119Sn).
119Sn NMR experiments were carried out aliasing by varying the
centre of the window, to avoid falling-out resonances, with a spec-
tral width of 900 ppm. Melting points were taken on an IA 8100
Electrothermal Instrument. The electrical conductances of the
dichloromethane and DMSO solutions were measured with a
Crison CDTM 522 conductimeter at room temperature.
(0.9 ꢁ 10ꢀ2 m)
(r = M.w./F.w. = 0.72),
671
(1.6 ꢁ 10ꢀ2 m)
(r = 0.76). IR (nujol) data: 1603vs, m(C@O), 585m, 558s, m(Sn–C),
439m, 406s, 376w
m
(Sn–O). 1H (CDCl3) NMR (293 K): d, 0.59s
[2J(119
H): 93.4 Hz, 2J(117
C): 88.9 Hz] (6H, Sn–CH3), 2.45s
1
13
Sn–
Sn–
(6H, C3–CH3), 5.57s (2H, (C6H5)2CHC@O), 7.18–7.26m, 7.80d
(30H, (C6H5)2CHC@O and N–C6H5). 1H (CDCl3) NMR (223 K): d,
1
1
0.79s [2J(119/117
:
98.3 Hz], 0.60s [2J(119/117
: 70.5 Hz]
Sn– H)
Sn– H)
(6H, Sn–CH3), 2.52s, 2.30s, 2.22s (6H, C3–CH3), 5.68s, 5.08s (2H,
(C6H5)2CHC@O), 7.03–7.38m, 7.45t, 7.68d, 7.72d (30H,
(C6H5)2CHC@O and N–C6H5). 13C (CDCl3) NMR (293 K): d, 8.7s
13
13
[1J(119
C): 895, 1J(117
C): 854 Hz] (Sn–CH3), 17.8s (C3–CH3),
Sn–
Sn–
58.4s ((C6H5)2CHC@O), 121.4s, 125.9s, 127.3s, 128.6s, 128.8s,
129.0s, 129.3s, 138.2s, 148.2s (Caromatic of QCHPh ), 105.1s (C4),
2
139.2s (C3), 163.1s (C5), 193.3s (CO). 119Sn (CDCl3) NMR (293 K):
d, ꢀ314.4. 119Sn (CDCl3) NMR (223): d, ꢀ307.3br. Derivatives
2–13 were synthesised and crystallised similarly.
4.2. Syntheses of the proligands
4.3.2. Bis(4-diphenylacetyl-3-methyl-1-phenyl-pyrazolon-5-ato)-
diethyltin(IV) ðQCHPh Þ SnEt2 (2)
2
4.2.1. 4-Diphenylacetyl-3-methyl-1-phenyl-pyrazol-5-one HQCHPh
2
2
Yield 51%. Mp 188–190 °C. Elemental analyses Calc for
3-Methyl-1-phenyl-pyrazol-5-one (15.0 g, 0.088 mol) was
placed in a flask equipped with a stirrer, separating funnel and a
reflux condenser. Dry dioxane (80 ml) was added by warming
and to the clear solution calcium hydroxide (12.0 g, 0.162 mol)
and then diphenylacetyl chloride (19.9 g, 0.087 mol) were added,
the latter dropwise for 10 min. The mixture was heated to reflux
for 4 h and then poured into HCl 2 N (300 ml) to decompose the
calcium complex. A red oily precipitate immediately formed,
which was separated from the solution and dried under reduced
pressure at 50 °C. Recrystallization was performed by treating
the solid with hot diethyl ether: slow cooling of the solution affor-
ded a brown-red crystalline powder. Yield 56%. Mp 113–115 °C.
Elemental analyses Calc. for C24H20N2O2: C, 73.4; H, 5.2; N, 10.1.
Found: C, 73.6; H, 5.2; N, 10.1%. IR (nujol) data: 2700–3200br,
C
52H48N4O4Sn: C, 68.5; H, 5.3; N, 6.1. Found: C, 68.3; H, 5.4; N,
6.0%. F.w. = 912; M.w. = 632 (0.8 ꢁ 10ꢀ2 m) (r = M.w./F.w. = 0.69),
724 (1.9 ꢁ 10ꢀ2 m) (r = 0.79). IR (nujol) data: 1595s,
m(C@O),
554s, 515m,
m
(Sn–C), 436s, 398s, 388s, 378s
m
(Sn–O). 1H (CDCl3)
NMR (293 K): d, 0.89t [3J(119
:
161.2 Hz, 2J(117
:
1
13
Sn– H)
Sn– C)
153.1 Hz], 1.26q [2J(119
:
107.2 Hz, 2J(117
: 103.3 Hz],
Sn– C)
1
13
Sn– H)
(10H, Sn–CH2CH3), 2.40s br (6H, C3–CH3), 5.68s br (2H,
(C6H5)2CHC@O), 7.12–7.29m br, 7.83m br (30H, (C6H5)2CHC@O
and N–C6H5). 1H (CDCl3) NMR (223 K): d, 0.78br, 0.89t br, 1.26br,
1.36q br, (10H, Sn–CH2CH3), 2.21s br, 2.52s br (6H, C3–CH3),
5.05s br, 5.73s br (2H, (C6H5)2CHC@O), 7.05–7.20m br, 7.22–
7.50m, 7.78d br (30H, (C6H5)2CHC@O and N–C6H5). 13C (CDCl3)
NMR (293 K): d, 9.2s [1J(119/117
C): 57 Hz] (Sn–CH2CH3), 17.9s
13
Sn–
(C3–CH3), 21.6s [1J(119
:
865, 1J(117
: 826 Hz] (Sn–
Sn– C)
13
13
m
(O–H. . .O); 1620vs, (C@O). 1H (CDCl3) NMR: d 2.42s, (3 H, C3–
m
Sn– C)
CH2CH3), 58.5s ((C6H5)2CHC@O), 121.2s, 125.7s, 127.3s, 128.5s,
CH3); 5.64s, (1 H, (C6H5)2CHC@O); 7.15–7.59m, 7.82d, (15 H,
128.6s, 128.8s, 129.1s, 129.3s, 138.3s, 148.2s (Caromatic of QCHPh ),
2
(C6H5)2CHC@O and N–C6H5); 11.3br, (1 H, OH. . .O).
105.5s (C4), 139.3s (C3), 163.2s (C5), 194.2s (CO). 119Sn (CDCl3)
NMR (293 K): d, ꢀ354.9. 119Sn (CDCl3) NMR (223): d, ꢀ345.1br.
4.2.2. 3-Methyl-1-phenyl-4-phenylacetylpyrazol-5-one HQBn
It was synthesised by a similar method of HQCHPh . Yield 82%.
2
4.3.3. Bis(4-diphenylacetyl-3-methyl-1-phenyl-pyrazolon-5-ato)-
Mp 104–106 °C. Elemental analyses Calc for C18H16N2O2: C, 74.0;
dicyclohexyltin(IV) (QCHPh )2SnCy2 (3)
2
H, 5.5; N, 9.6. Found: C, 73.9; H, 5.6; N, 9.6%. IR (nujol) data:
Yield 65%. Mp 223–227 °C. Elemental analyses Calc for
2400–2800br,
m m
(O–H. . .O); 1619vs, (C@O). 1H (CDCl3) NMR: d
C
60H60N4O4Sn: C, 70.7; H, 6.0; N, 5.5. Found: C, 70.5; H, 6.2; N,
5.3%. IR (nujol) data: 1604s, (C@O), 556s, 426s, (Sn–C), 439m,
390m, 371m
(Sn–O). 1H (CDCl3) NMR (293 K): d, 0.94–1.79m br
2.53s, (3H, C3–CH3); 4.09s, (2H, C6H5CH2C@O); 7.12–7.48m,
m
m
7.82d, (10H, C6H5CH2C@O and N–C6H5); 10.6br, (1H, OH. . .O).
m
(22H, Sn–C6H11), 2.45s, 248s (6H, C3–CH3), 5.73s br (2H,
4.2.3. 3-Methyl-4-naphthoyl-1-phenyl-pyrazol-5-one HQnaph
(C6H5)2CHC@O), 7.07m br, 7.26m br, 7.82m br (30H,
It was synthesised by a similar method of HQCHPh . Yield 88%.
2
(C6H5)2CHC@O and N–C6H5). 13C (CDCl3) NMR (293 K): d,
17.8s (C3–CH3), 26.6s, 28.4s [2J(119/117
C): 32 Hz], 29.0s, 47.5s
13
Mp 177–183 °C. Elemental analyses Calc for
76.81; H, 4.91; N, 8.53. Found: C, 76.32; H, 5.11; N, 8.50%. IR (nujol)
data: 2400–2800br,
(O–H. . .O); 1616vs, (C@O). 1H (CDCl3) NMR:
C21H16N2O2: C,
Sn–
[1J(119
:
842, 1J(117
:
804 Hz] (Sn–C6H11), 59.1s
13
13
Sn– C)
Sn– C)
m
m
((C6H5)2CHC@O), 121.1s, 125.5s, 127.2s, 128.5s, 128.6s, 128.8s,
129.0s, 129.1s, 129.4s, 129.5s, 138.5s, 148.2s (Caromatic of QCHPh ),
2
d 1.63s, (3H, C3–CH3); 7.30t, 7.60m, 7.92dd, 8.03m (12H, C–Hnaph
and N–C6H5); 4.8br, (1H, OH. . .O).
105.3s (C4), 139.5s (C3), 163.1s (C5), 193.6s (CO). 119Sn (CDCl3)
NMR (293 K): d, ꢀ430.1.
4.3. Syntheses of the metal derivatives
4.3.4. Bis(4-diphenylacetyl-3-methyl-1-phenyl-pyrazolon-5-ato)-
t
2
4.3.1. Bis(4-diphenylacetyl-3-methyl-1-phenyl-pyrazolon-5-ato)-
ditert-butyltin(IV) (QCHPh Þ2SnBu (4)
2
dimethyltin(IV) ðQCHPh Þ SnMe2 (1)
Yield 50%. Mp 168–170 °C. Elemental analyses Calc for
56H56N4O4Sn: C, 69.5; H, 5.8; N, 5.8. Found: C, 69.2; H, 5.9; N,
2
2
To a methanol solution (30 ml) of HQCHPh (2 mmol) were added
C
2
KOH (2 mmol) and (CH3)2SnCl2 (1 mmol). A precipitate formed
5.7%. IR (nujol) data: 1596vs, (C@O), 559s, 427m, (Sn–C),
m
m

82
F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
442m, 390sh, 386s, 372s
m
(Sn–O). 1H (CDCl3) NMR (293 K): d, 0.80s
125.4s, 127.0s, 128.7s, 129.1s, 129.4, 135.2s, 148.4s (Caromatic of
QBn), 105.1s (C4), 138.6s (C3), 162.9s (C5), 193.1s (CO). 119Sn
(CDCl3) NMR (293 K): d, ꢀ431.0.
1
br, [2J(119/117
H): 87.4 Hz] (18H, Sn–C(CH3)3), 2.41s br (6H, C3–
Sn–
CH3), 5.69s br (2H, (C6H5)2CHC@O), 7.09–7.40m br, 7.79d br
(30H, (C6H5)2CHC@O and N–C6H5). 13C (CDCl3) NMR (293 K): d,
17.9br (C3–CH3), 29.0br (Sn–C(CH3)3), 46.2br (Sn–C(CH3)3), 59.4br
((C6H5)2CHC@O), 121.2br, 125.6br, 127.3br, 128.6br, 128.8br,
4.3.9. Bis(3-methyl-1-phenyl-4-phenylacetylpyrazolon-5-ato)di-t-
butyltin(IV) ðQBnÞ2SnBut (9)
129.1br, 129.5br, 129.6br, 138.4br, 148.1br (Caromatic of QCHPh ),
2
2
Yield 85%. Mp 161–162 °C. Elemental analyses Calc for
106.6br (C4), 139.3br (C3), 164.1br (C5), 194.4br (CO). 119Sn (CDCl3)
NMR (293 K): d, ꢀ445.0br.
C
44H48N4O4Sn: C, 64.8; H, 5.9; N, 6.9. Found: C, 64.5; H, 6.0; N,
6.9%. IR (nujol) data: 1603s, (C@O), 572m, 545s, 478w, 433vs,
(Sn–C), 460m, 433s, 408m, 390s,
(Sn–O). 1H (CDCl3) NMR
m
m
m
4.3.5. Bis(4-diphenylacetyl-3-methyl-1-phenyl-pyrazolon-5-ato)-
(293 K): d, 0.98s [3J(Sn–H): 133.4, 127.2 Hz] (18H, Sn–C4H9), 2.52s
(6H, C3–CH3), 3.99s (4H, C6H5CH2C@O), 7.12–7.35m, 7.86dd
(20H, C6H5CH2C@O and N–C6H5). 13C (CDCl3) NMR (293 K): d,
17.9br (C3–CH3), 29.3br (Sn–C(CH3)3), 30.2br (Sn–C(CH3)3), 45.7br
(C6H5CH2C@O), 120.9br, 125.4br, 127.0br, 128.5br, 129.1br,
129.8br, 134.7br, 148.3br (Caromatic of QBn), 105.8br (C4), 138.6br
(C3), 163.4br (C5), 193.2br (CO). 119Sn (CDCl3) NMR (293 K): d,
ꢀ455.2br.
diphenyltin(IV) (QCHPh )2SnPh2 (5)
2
Yield 59%. Mp 142–144 °C. Elemental analyses Calc for
C
60H48N4O4Sn: C, 71.5; H, 4.8; N, 5.6. Found: C, 71.3; H, 4.7; N,
5.4%. IR (nujol) data: 1611s, (C@O), 268s, 243m, (Sn–C), 448s
br, 416w, 348m
(Sn–O). 1H (CDCl3) NMR (293 K): d, 2.82s, 2.42s
m
m
m
(6H, C3–CH3), 5.20s, 5.56s (2H, (C6H5)2CHC@O), 6.83–7.38m,
7.46t, 7.72m, 7.96d (40H, (C6H5)2CHC@O, N–C6H5 and Sn–C6H5).
13C (CDCl3) NMR (293 K): d, 17.9br (C3–CH3), 58.6br
((C6H5)2CHC@O), 121.4br, 126.1br, 127.3br, 127.8br, 128.7br,
128.9br, 129.4br, 138.1br, 148.2br (Caromatic of QCHPh and Sn–
4.3.10. Bis(3-methyl-1-phenyl-4-phenylacetylpyrazolon-5-ato)-
diphenyltin(IV) (QBn)2SnPh2 (10)
2
C6H5), 106.1br (C4), 139.3br (C3), 163.0br (C5), 194.4br (CO).
119Sn (CDCl3) NMR (293 K): d, ꢀ493.2br.
Yield 79%. Mp 165–167 °C. Elemental analyses Calc for
C
48H40N4O4Sn: C, 67.4; H, 4.7; N, 6.5. Found: C, 67.2; H, 4.8; N,
6.7%. F.w. = 856. IR (nujol) data: 1605s br, (C@O), 265s, 244s,
(Sn–C), 445vs br, 404w, 385m br
(Sn–O). 1H (CDCl3) NMR
4.3.6. Bis(3-methyl-1-phenyl-4-phenylacetylpyrazolon-5-ato)-
dimethyltin(IV) (QBn)2SnMe2 (6)
m
m
m
Yield 62%. Mp 153–155 °C. Elemental analyses Calc for
(293 K): d, 2.35s br, 2.47s br (6H, C3–CH3), 3.72s br, 3.87s br (4H,
C6H5CH2C@O), 6.94–7.53m br, 7.82d br (30H, C6H5CH2C@O, N–
C6H5 and Sn–C6H5). 13C (CDCl3) NMR (293 K): d, 17.3br, 17.6br
(C3–CH3), 44.5br, 44.9br (C6H5CH2C@O), 121.0br, 121.2br, 125.9br,
126.9br, 127.5br, 128.0br, 128.1br, 128.4br, 128.6br, 128.7br,
129.0br, 130.7br, 133.8br, 135.2br, 148.1br, 148.3br, 148.6br (Caro-
matic of QBn and of Sn–C6H5), 104.5br, 105.3br (C4), 136.2br, 137.9br
(C3), 163.5br (C5), CO not observed. 119Sn (CDCl3) NMR (293 K): d,
ꢀ487.2br, ꢀ490.5br.
C
50H44N4O4Sn: C, 62.4; H, 5.0; N, 7.7. Found: C, 62.3; H, 5.1; N,
7.8%. IR (nujol) data: 1593vs, (C@O), 593m, 575sh, 543w (Sn–
C), 460s, 447s, 440m, 405w, 395m
(Sn–O). 1H (CDCl3) NMR
m
m
m
(293 K): d, 0.75s [2J(119
H): 99.7 Hz, 2J(117
C): 95.3 Hz] (6H,
1
13
Sn–
Sn–
Sn–CH3), 2.45s (6H, C3–CH3), 3.97s (4H, C6H5CH2C@O), 7.17–
7.31m, 7.84dd (20H, C6H5CH2C@O and N–C6H5). 13C (CDCl3) NMR
(293 K): d, 9.1s [1J(119
C): 922, 1J(117
C): 880 Hz] (Sn–CH3),
Sn–
13
13
Sn–
17.6s (C3–CH3), 45.5s (C6H5CH2C@O), 121.3s, 125.8s, 127.1s,
128.8s, 129.1s, 135.0s, 148.6s (Caromatic of QBn), 104.8s (C4),
138.3s (C3), 162.6s (C5), 192.8s (CO). 119Sn (CDCl3) NMR (293 K):
d, ꢀ318.2.
4.3.11. Bis(3-methyl-4-naphthoyl-1-phenyl-pyrazolon-5-ato)-
dimethyltin(IV) (Qnaph)2SnMe2 (11)
Yield 75%. Mp 207–208 °C. Elemental analyses: Calc for
4.3.7. Bis(3-methyl-1-phenyl-4-phenylacetylpyrazolon-5-ato)-
diethyltin(IV) (QBn)2SnEt2 (7)
C
44H36N4O4Sn: C, 65.77; H, 4.52; N, 6.97. Found: C, 65.28; H,
4.64; N, 6.99%. IR (nujol, cmꢀ1): 1600vs
m
(C@O), 568s, 528m
Yield 74%. Mp 141–143 °C. Elemental analyses Calc for
m
(Sn–C), 463w, 448m, 433m, 400s, 389s, 372m m
(Sn–O). 1H NMR
C42H40N4O4Sn: C, 63.3; H, 5.3; N, 7.4. Found: C, 63.1; H, 5.4; N,
(CDCl3) (293 K): d, 1.20s (2J(Sn–H): 101.4, 96.8 Hz) (6H, Sn–CH3),
7.4%. IR (nujol) data: 1610s, m(C@O), 556s, 521m m(Sn–C), 461s,
1.40s (6H, C3–CH3), 7.20m, 7.48m, 7.90dd, 7.96m (24H, C–Hnaph
440s, 427s, 403m br
m
(Sn–O). 1H (CDCl3) NMR (293 K): d, 1.43q
and N1–C6H5). 13C NMR (CDCl3) (293 K): d, 9.8s [1J(119
:
13
Sn– C)
[2J(119
H): 86.6 Hz, 2J(117
C): 83.3 Hz], 1.04t [3J(Sn–H): 161.8,
1
13
Sn–
Sn–
906 Hz, 1J(117
C): 865 Hz] (Sn–CH3), 15.5s (C3–CH3), 121.0,
13
Sn–
154.6 Hz] (10H, Sn–CH2CH3), 2.48s (6H, C3–CH3), 4.00s (4H,
C6H5CH2C@O), 7.15–7.38m, 7.82–7.91m (20H, C6H5CH2C@O and
124.7, 124.8, 125.0, 125.7, 126.6, 127.3, 128.4, 129.0, 129.8,
130.2, 133.5, 137.1, 150.2s (Cnaph and N1–C6H5), 106.3s (C4),
138.2s (C3), 162.6s (C5), 191.2s (CO). 119Sn NMR (CDCl3) (293 K):
d, ꢀ319.8.
N–C6H5). 13C (CDCl3) NMR (293 K): d, 9.4s [1J(119/117
C): 54 Hz]
:
13
Sn–
(Sn–CH2CH3), 17.6s (C3–CH3), 21.8s [1J(119
856,
13
Sn– C)
1J(117
C): 818 Hz] (Sn–CH2CH3), 45.5s (C6H5CH2C@O), 121.0s,
13
Sn–
125.5s, 127.0s, 128.7s, 129.0s, 135.0s, 148.5s (Caromatic of QBn),
104.9s (C4), 138.4s (C3), 162.7s (C5), 193.1s (CO). 119Sn (CDCl3)
NMR (293 K): d, ꢀ356.6.
4.3.12. Bis(3-methyl-4-naphthoyl-1-phenyl-pyrazolon-5-ato)di-n-
butyltin(IV) ðQnaphÞ2SnBun (12)
2
Yield 72%. Mp 151–153 °C. Elemental analyses: Calc for
4.3.8. Bis(3-methyl-1-phenyl-4-phenylacetylpyrazolon-5-ato)-
dicyclohexyltin(IV) (QBn)2SnCy2 (8)
C48H48N4O4Sn: C, 66.76; H, 5.60; N, 6.49. Found: C, 66.72; H,
5.78; N, 6.28%. IR (nujol, cmꢀ1): 1596s
C), 440m, 405w, 396w, 383m, 369s
m
(C@O), 566s, 529s
m(Sn–
Yield 82%. Mp 164–165 °C. Elemental analyses Calc for
m
(Sn–O). 1H NMR (CDCl3)
C
48H52.N4O4Sn: C, 66.4; H, 6.0; N, 6.5. Found: C, 66.1; H, 6.2; N,
6.5%. IR (nujol) data: 1614s, (C@O), 534m, 520s, 497s (Sn–C),
461m, 444s, 421s, 404m, 391s
(Sn–O). 1H (CDCl3) NMR (293 K):
(293 K): d, 0.87t, 1.45m, 1.85m (18H, Sn–C4H9), 1.61s (6H, C3–
CH3), 7.20m, 7.50m, 7.91dd, 8.00m (24H, C–Hnaph and N1–C6H5).
13C NMR (CDCl3) (293 K): d, 15.7s (C3–CH3), 13.9s, 26.4s
m
m
m
[3J(119/117
:
138 Hz], 27.5s [3J(119/117
: 45 Hz], 29.8s
C): 831 Hz] (Sn–C4H9), 120.9, 124.8,
13
13
d, 0.98–1.82m (22H, Sn–C6H11), 2.52s (6H, C3–CH3), 4.02s (4H,
C6H5CH2C@O), 7.11–7.35m, 7.88dd (20H, C6H5CH2C@O and N–
C6H5). 13C (CDCl3) NMR (293 K): d, 17.8s (C3–CH3), 26.8s, 28.9s
Sn– C)
13
Sn– C)
[1J(119
C): 870 Hz, 1J(117
13
Sn–
Sn–
124.9, 125.2, 125.7, 126.7, 127.4, 128.7, 129.2, 130.0, 130.3,
150.3s (N1–C6H5), 106.6s (C4), 138.5s (C3), 162.9s (C5), 191.8s
(CO). 119Sn NMR (CDCl3) (293 K): d, ꢀ354.0br.
[2J(119/117
:
32 Hz], 29.5s, 45.7s [1J(119
:
837,
13
13
Sn– C)
13
Sn– C)
1J(117
: 801 Hz] (Sn–C6H11), 47.3s (C6H5CH2C@O), 120.9s,
Sn– C)

F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
83
4.3.13. Bis(3-methyl-4-naphthoyl-1-phenyl-pyrazolon-5-
4.5. 119Sn solid state NMR
ato)diphenyltin(IV) (Qnaph)2SnPh2 (13)
Yield 77%. Mp 247–250 °C. Elemental analyses: Calc for
High-resolution solid-state 119Sn magic-angle-spinning (MAS)
NMR spectra were acquired at ambient temperatures using a Bru-
ker DSX-400 NMR spectrometer (B0 = 9.4 T) operating at a 119Sn
Larmor frequency of 149.20 MHz. These experiments were con-
ducted using a Bruker 3.2 mm double-air-bearing MAS probe from
which rotational frequencies of 4 and 10 kHz were implemented.
All experimental data were acquired under 1H–119Sn cross-polari-
sation conditions which used recycle delays of 5–10 s, Hartmann–
C
54H40N4O4Sn: C, 69.92; H, 4.35; N, 6.04. Found: C, 69.54; H,
3.58; N, 6.4%. IR (nujol, cmꢀ1): 1604vs
(C@O), 448vs, 434m,
403m, 392m (Sn–O), 267m, 245m, 225m
(Sn–C). 1H NMR (CDCl3)
m
m
m
(293 K): d, 1.21br, 1.69s (6H, C3–CH3), 7.20–7.60m, 7.80–8.10m
(34H, Sn–C6H5, C–Hnaph and N1–C6H5). 13C NMR (CDCl3) (293 K):
d, 15.4br (C3–CH3), 120.9br, 121.3br, 123.7br, 125.0br, 126.2br,
126.6br, 127.2br, 128.4br, 129.1br, 129.9br, 130.2br, 133.4br,
135.6br, 136.6br, 148.2br, 150.6br, (Sn–C6H5, C–Hnaph and N1–
C6H5), 107.3br (C4), 138.0br (C3), 163.9br (C5), 191.8br (CO).
119Sn NMR (CDCl3) (293 K): d, ꢀ479.8br, ꢀ486.8br, ꢀ740.6.
Hahn contact periods of 5 ms, and an initial 1H
p/2 pulse width of
3.5
l
s. A nominal 1H decoupling field strength of ꢃ80 kHz was em-
ployed during acquisition. Each spectrum was externally refer-
enced to the Sn primary reference Me4Sn (d 0.0 ppm) via a
secondary reference Cy4Sn located upfield at d ꢀ97.35 ppm [30].
This sample of Cy4Sn was also used to establish the Hartmann–
Hahn contact condition required for cross-polarisation data acqui-
sition. The 119Sn CPMAS spectrum of each complex was acquired at
two different MAS frequencies to allow an unambiguous assign-
ment of the isotropic chemical shift (diso), and to clearly identify
the chemical shift tensor elements d11, d22 and d33. The MAS
NMR spectra acquired at 4 kHz were more selectively utilised to
identify d11, d22 and d33 since increased MAS rates invoked the
appearance of biasing the downfield tensorial positions to low-
er ppm values and the upfield tensorial positions to higher ppm
values. Parameters defining the chemical shift interaction were
calculated from these measured chemical shift tensorial elements
(d11, d22, d33) according to IUPAC-recognised conventions as dis-
cussed by Mason [31] and Mackenzie et al. [32]. The Herzfeld–
Berger convention is described by using the isotropic chemical
4.4. Structure determinations
For complex (2), a unique data single counter diffractometer set
(Syntex P21 modified by Crystallogic) was measured at 298 K; for
the complexes (1) and (12), full spheres of CCD/area detector data
were measured at ca. 153 K (monochromatic Mo K
a radiation,
k = 0.71073 Å (all structures)); for (6) T was 100 K. All unique data
were included in the full matrix least squares refinements, refining
anisotropic displacement parameter forms for the non-hydrogen
atoms, hydrogen atom treatment following a riding model. Neutral
atom complex scattering factors were employed. Full cif deposi-
tions reside with the Cambridge Crystallographic Data Centre,
CCDC 779497 (1), 783539 (2), 787995 (6), 779909 (12).
4.4.1. Crystal/refinement data
4.4.1.1. [ðQCHPh Þ SnMe2] (1). „C50H44N4O4Sn, Mr = 883.6. Mono-
2
2
shift diso = (d11 + d22 + d33)/3 (d11 > d22 > d33), span
and skew (where 1 P
= 3(d22 ꢀ diso)/(d11 ꢀ d33
alternative representation such as the Haeberlen convention uses
the anisotropy ( d) and asymmetry ( ) if a different frequency
convention |d33 ꢀ diso| P |d11 ꢀ diso| P |d22 ꢀ diso| is invoked; in this
case the anisotropy
d = d33 ꢀ (d11 + d22)/2) = 3(d33 ꢀ diso)/2 and
asymmetry is restricted within
= (d22 ꢀ d11)/(d33 ꢀ diso), where
the range 1 P P 0.
X
j
= (d11 ꢀ d33),
clinic,
space
group
P21/c
ðC52h; No: 14Þ,
a = 11.102(2),
j
)
P ꢀ1). An
b = 15.713(2), c = 24.098(3) Å, b = 98.235(3)°, V = 4160(1) Å3. Dc
(Z = 4) = 1.411 g cmꢀ3
0.32 ꢁ 0.22 mm; ‘T’min/max
tion) = 0.90. 2hmax = 70°; 78,052 total reflections, merging to
.
l
Mo = 0.67 mmꢀ1
;
specimen: = 0.36 ꢁ
D
g
(‘empirical’/multiscan
correc-
D
18,421 unique (Rint = 0.047), 12,907 with I > 2r(I). R1 = 0.044,
g
g
wR2 = 0.110. Refinement on F2 (reflection weights:
ð
r2ðF2oÞ þ
g
2
ð0:050PÞ þ 1:62PÞꢀ1 ðP ¼ ðFo2 þ 2F2c Þ=3Þ) (SHELXL 97 [27]).
4.4.1.2. [ðQCHPh Þ SnEt2] (2). „C52H48N4O4Sn, Mr = 911.7. Mono-
2
Acknowledgements
2
clinic, space group P21/c, a = 11.135(8), b = 16.427(12), c =
24.72(2) Å, b = 98.29(2)°, V = 4474(6) Å3. Dc (Z = 4) = 1.354 g cmꢀ3
.
Financial support by Università degli Studi di Camerino, Consi-
glio Nazionale delle Ricerche C.N.R.- Rome, Research Committee
and URSI program at Vassar College. JVH thanks EPSRC and the
University of Warwick for partial funding of the solid state NMR
infrastructure at Warwick, and acknowledges additional support
for this infrastructure obtained through Birmingham Science City:
Innovative Uses for Advanced Materials in the Modern World
(West Midlands Centre for Advanced Materials Project 2), with
support from Advantage West Midlands (AWM) and partial fund-
ing by the European Regional Development Fund (ERDF). MR
thanks the Camille and Henry Dreyfus Foundation for diffractome-
ter funds.
l
Mo = 0.62 mmꢀ1; specimen: = 0.30 ꢁ 0.30 ꢁ 0.07 mm; ‘T’min/max
=
0.85 (semi-empirical correction [28]). 2hmax = 60°; 12,943 unique
reflections, 6075 with F > 6
wR = 0.085 (CAOS [29]).
r(F). Refinement on |F|, Rf = 0.057,
4.4.1.3. [(QBn)2SnMe2] (6). „C38H36N4O4Sn, Mr = 731.4. Monoclinic,
space group P21/n, a = 10.7778(14), b = 15.6439(14),
c = 19.920(3) Å, b = 95.985(15)°, V = 3340.3(8) Å3. Dc (Z = 4) =
1.454 g cmꢀ3 Mo = 0.81 mmꢀ1
0.07 mm; ‘T’min/max (face-indexed ‘analytical’ correction) = 0.46.
2hmax = 70°; 48,223 total reflections, merging to 13,850 unique
.
l
;
specimen: = 0.67 ꢁ 0.46 ꢁ
(Rint = 0.077), 9917 with I > 2r(I). R1 = 0.047, wR2 = 0.118. Refine-
2
ment on F2 (reflection weights: ðr2ðFo2Þ þ ð0:072PÞ Þꢀ1) (SHELXL
References
97 [27]).
[1] P.G. Harrison, Chemistry of Tin, Blackie, Glasgow, 1989.
[2] (a) M. Gielen, E.R.T. Tiekink, Metallotherapeutic Drugs and Metal-Based
Diagnostic Agents: The Use of Metals in Medicine, John Wiley & Sons, United
Kingdom, 2005;
4.4.1.4. [ðQnaphÞ2SnBun ] (12). „C50H48N4O4Sn, Mr = 887.6. Mono-
2
clinic, space group P21/n, a = 11.462(2), b = 21.069(4),
c = 18.333(3) Å, b = 105.280(6)°, V = 4271(1) Å3. Dc (Z = 4) =
(b) A.G. Davies, M. Gielen, K.H. Pannell, E.R.T. Tiekink, Tin Chemistry:
Fundamentals, Frontiers, and Applications, John Wiley
Kingdom, 2008.
& Sons, United
1.380 g cmꢀ3
.
l
Mo = 0.65 mmꢀ1
;
specimen:
0.18 ꢁ 0.16 ꢁ
(I).
[3] A.J. Crowe, P.J. Smith, C.J. Cardin, H.E. Parge, F.E. Smith, Cancer Lett. 24 (1984)
45.
[4] G. Han, P. Yang, J. Inorg. Biochem. 91 (2002) 230. and references therein.
[5] (a) G.A. Miller, E.O. Schlemper, Inorg. Chem. 12 (1977) 677;
(b) G. Poli, C.J. Cheerand, W.H. Nelson, J. Organomet. Chem. 306 (1986) 347;
0.08 mm; ‘T’min/max = 0.71. 2hmax = 52°; 29,386 total reflections,
merging to 8359 unique (Rint = 0.075), 5552 with I > 2
r
R1 = 0.056, wRꢀ21= 0.15. Refinement on F2 (reflection weights:
ð
r2ðF2oÞ þ 2:1PÞ (SHELXL 97 [27]).

84
F. Caruso et al. / Inorganica Chimica Acta 367 (2011) 73–84
(c) C. Sreelatha, D.K. Srivastava, V.D. Gupta, H. Nöth, J. Chem. Soc., Dalton Trans.
(1988) 407.
[6] (a) G.A. Miller, E.O. Schlemper, Inorg. Chim. Acta 30 (1978) 131;
(b) J. Angenault, C. Mondi, A. Rimsky, Inorg. Chim. Acta 37 (1979) 145;
(c) D. Searle, P.J. Smith, N.A. Bell, L.A. March, I.W. Nowell, J.D. Donaldson, Inorg.
Chim. Acta 162 (1989) 143.
[7] K. Venkataraman, The Chemistry of Dyes, vol.1, Academic Press, New York,
1952.
[8] (a) Y.A. Zolotov, N.M. Kuzmin, in: Metal Extraction with Acylpyrazolones, Izdat
Nauka, Moscow, 1977;
(b) E.C. Okafor, Z. Naturforsch. Teil B 36 (1981) 213;
(c) S. Umetani, H. Freiser, Inorg. Chem. 26 (1987) 3179;
(d) E.C. Okafor, B.A. Uzoukwu, Radiochim. Acta 51 (1990) 167.
[9] (a) E.C. Okafor, Spectrochim. Acta, Part A 37 (1987) 939;
(b) R. Morales, H. Nekimken, C.S. Bartholdi, P.T. Cunningham, Spectrochim.
Acta, Part A 44 (1988) 165. and references therein.
[13] (a) R.R. Ryan, G.D. Jarvinen, Acta Crystallogr., Part C 43 (1987) 1295;
(b) E.C. Okafor, A.B. Uzoukwu, P.B. Hitchcock, J.D. Smith, Inorg. Chim. Acta 172
(1990) 97.
[14] F. Marchetti, C. Pettinari, A. Cingolani, D. Leonesi, M. Camalli, A. Pifferi,
Polyhedron 15 (1996) 3835.
[15] M.F. Mahon, K.C. Molloy, B.A. Omotowa, M.A. Mesubi, J. Organomet. Chem. 525
(1996) 239.
[16] (a) T.P. Lockhart, W.F. Manders, Inorg. Chem. 25 (1986) 892;
(b) B. Wrackmeyer, Ann. Rep. NMR Spectrosc. 16 (1985) 73;
(c) W.F. Howard Jr., R.W. Crecely, W.H. Nelson, Inorg. Chem. 24 (1985) 2204.
[17] W.F. Howard, R.W. Crecely, W.H. Nelson, Inorg. Chem. 24 (1985) 2204.
[18] C. Pettinari, F. Caruso, N. Zaffaroni, R. Villa, F. Marchetti, R. Pettinari, C. Phillips,
J. Tanski, M. Rossi, J. Inorg. Biochem. 100 (2006) 58.
[19] F. Caruso, M. Rossi, F. Marchetti, C. Pettinari, Organometallics 18 (1999) 2398.
[20] C. Pettinari, F. Marchetti, R. Pettinari, A. Cingolani, A. Drozdov, S. Troyanov, J.
Chem. Soc., Dalton Trans. (2002) 188.
[10] (a) S. Saxena, R. Bhora, A.K. Ray, Inorg. Chim. Acta 173 (1990) 191;
(b) C. Pettinari, G. Rafaiani, G. Gioia Lobbia, A. Lorenzotti, B. Bovio, J.
Organomet. Chem. 458 (1991) 75;
[21] C. Camacho-Camacho, R. Contreras, H. Noth, M. Bechmann, A. Sebald, W.
Milius, B. Wrackmeyer, Magn. Reson. Chem. 40 (2002) 31.
[22] C. Di Nicola, A. Galindo, J.V. Hanna, F. Marchetti, C. Pettinari, R. Pettinari, E.
Rivarola, B.W. Skelton, A.H. White, Inorg. Chem. 44 (2005) 3094.
[23] A. Sebald, Advanced applications of NMR to organometallic chemistry, in:
Solid State NMR Applications in Organotin and Organolead Chemistry, John
Wiley & Sons, Chichester, UK, 1996, pp. 123–155 (Chapter 5).
[24] R.K. Harris, A. Sebald, J. Organomet. Chem. 331 (1987) C9.
[25] S.W. Ng, J.M. Hook, M. Gielen, Appl. Organomet. Chem. 14 (2000) 1.
[26] B.E. Eichler, B.L. Phillips, P.P. Power, M.P. Augustine, Inorg. Chem. 39 (2000)
5450.
(c) B. Bovio, A. Cingolani, F. Marchetti, C. Pettinari, J. Organomet. Chem. 458
(1993) 39;
(d) C. Pettinari, F. Marchetti, D. Leonesi, M. Rossi, F. Caruso, J. Organomet.
Chem. 483 (1994) 123;
(e) A. Jain, S. Saxena, R. Bohra, A.K. Ray, Main Group Met. Chem. 18 (1995) 139;
(f) C. Pettinari, F. Marchetti, A. Gregori, A. Cingolani, J. Tanski, M. Rossi, F.
Caruso, Inorg. Chim. Acta 257 (1997) 37;
(g) C. Pettinari, F. Marchetti, A. Cingolani, D. Leonesi, E. Mundorff, M. Rossi, F.
Caruso, J. Organomet. Chem. 557 (1998) 187;
[27] G.M. Sheldrick, Acta Crystallogr., Sect. A 64 (2008) 112.
[28] A.C.T. North, D.C. Phillips, F.S. Mathews, Acta Crystallogr., Sect. A 24 (1968)
351.
(h) F. Marchetti, C. Pettinari, M. Rossi, F. Caruso, Main Group Met. Chem. 21
(1998) 255.
[11] (a) F. Caruso, D. Leonesi, F. Marchetti, E. Rivarola, M. Rossi, V. Tomov, C.
Pettinari, J. Organomet. Chem. 519 (1996) 29;
(b) C. Pettinari, F. Marchetti, A. Cingolani, A. Lorenzotti, E. Mundorff, M. Rossi,
F. Caruso, Inorg. Chim. Acta 262 (1997) 33.
[12] B.A. Uzoukwu, P.U. Adiukwu, S.S. Al-Juaid, P.B. Hitchcock, J.D. Smith, Inorg.
Chim. Acta 250 (1996) 173.
[29] M. Camalli, R. Spagna, J. Appl. Crystallogr. 27 (1994) 861.
[30] J. Kümmerlen, A. Sebald, H. Reuter, J. Organomet. Chem. 427 (1992) 309.
[31] J. Mason, Solid State Nucl. Magn. Reson. 2 (1993) 285.
[32] J.K.D. Mackenzie, M.E. Smith, Multinuclear Solid State NMR of Inorganic
Materials, Pergamon, Oxford, UK, 2002.