Tin(IV) and organotin(IV) derivatives of bis(pyrazolyl)acetate: Synthesis, spectroscopic characterization and behaviour in solution.: X-ray single crystal study of bis(pyrazol-1-yl)acetatotri-iodotin(IV) [SnI3(bdmpza)]

Article abstract of DOI:10.1016/j.jorganchem.2005.01.067

Novel heteroscorpionate-containing tin and organotin(IV) complexes, [SnR_nX_{3 - n}(L)], R = Me, Buⁿ, Ph, or cy; X = Cl, Br or I, n = 0, 1, 2 or 3; L = bis(pyrazol-1-yl)acetate (bpza) or bis(3,5-dimethylpyrazol-1-yl)acetate (b

Full text of DOI:10.1016/j.jorganchem.2005.01.067

Journal of Organometallic Chemistry 690 (2005) 1878–1888
www.elsevier.com/locate/jorganchem
Tin(IV) and organotin(IV) derivatives of bis(pyrazolyl)acetate:
Synthesis, spectroscopic characterization and behaviour in solution.
X-ray single crystal study of
bis(pyrazol-1-yl)acetatotri-iodotin(IV) [SnI3(bdmpza)]
a
a
a,
a
Fabio Marchetti , Maura Pellei , Claudio Pettinari *, Riccardo Pettinari ,
b
a
c
Eleonora Rivarola , Carlo Santini , Brian W. Skelton , Allan H. White
c
a
`
Dipartimento di Scienze Chimiche, Universita degli Studi di Camerino, via S. Agostino 1, 62032 Camerino, Italy
b
`
Dipartimento di Chimica Inorganica e Analitica Stanislao Cannizzaro, Universita di Palermo, Italy
c
Chemistry M313, The University of Western Australia, Crawley, WA 6009, Australia
Received 23 December 2004; accepted 4 January 2005
Available online 23 March 2005
Abstract
Novel heteroscorpionate-containing tin and organotin(IV) complexes, [SnRnX3 ꢀ n(L)], R = Me, Bun, Ph, or cy; X = Cl, Br or I,
n = 0, 1, 2 or 3; L = bis(pyrazol-1-yl)acetate (bpza) or bis(3,5-dimethylpyrazol-1-yl)acetate (bdmpza), have been synthesized and
1
characterized by spectral (IR, H, 13C and 119Sn NMR, 119mSn Mo¨ssbauer) and analytical data. In [SnI3(bdmpza)], the ligand is
fac-N,N0,O-tridentate, the three iodine atoms thus also fac about the six-coordinate tin(IV) atom. Neutral bpzaH reacts with
BunSnCl3, PhSnCl3 and SnCl4 in Et2O in the absence of base, yielding 1:1 adducts [XSnCl3(bpzaH)] (X = R or Cl).
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Organotin complexes; Heteroscorpionates; 119Sn NMR; 119mSn Mo¨ssbauer; X-ray study
1. Introduction
pyrazole [2]. It is now accepted that the electronic and
steric properties of the Tpx ligands can strongly influ-
ence both the structure and properties of their metal
complexes. The poly(pyrazolyl)borate ligands are sym-
metrical with respect to the nitrogen donors, and are un-
able to mimic many metalloprotein active sites which
lack similar monofunctional, highly organized donor
spheres.
Bis(pyrazolyl)acetates are ligands closely related to
both neutral tris(pyrazolyl)methane and anionic
poly(pyrazolyl)borates in respect of their classical
‘‘pinch and sting’’ behaviour (Fig. 1), one of the pyraz-
olyl groups being replaced by a carboxylate moiety [2].
This change introduces a small degree of steric hin-
drance and considerable coordinative ligand flexibility.
Bis(pyrazolyl)acetates can be easily deprotonated,
Poly(pyrazolyl)borates and poly(pyrazolyl)alkanes
constitute a family of stable and flexible polydentate iso-
electronic and isosteric ligands discovered by Tro-
fimenko [1]. They represent one of the most widely
used classes of ligands in transition and main group me-
tal coordination chemistry [2]. Although the anionic Tpx
(a generic tris(pyrazolyl)borate) are often described as
an equivalent to C5H5 (Cp) or C5Me5 (Cp*), they also
exhibit a number of significant differences arising from
the lesser p-acceptor and greater r-donor abilities of
*
Corresponding author. Tel.: +39 0737 402234; fax: +39 0737
637345.
E-mail address: claudio.pettinari@unicam.it (C. Pettinari).
0022-328X/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.01.067

F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
1879
multiplicities are abbreviated: singlet, s; doublet, d; trip-
let, t; multiplet, m. Melting points are uncorrected and
were measured using an SMP3 Stuart scientific instru-
ment, and on a capillary apparatus. The electrical con-
ductivity measurements of dichloromethane solutions
of complexes 1–19 were made with a Crison CDTM
522 conductimeter at room temperature.
119Sn Mo¨ssbauer spectra were recorded on solid sam-
ples at liquid nitrogen temperature using a conventional
constant acceleration spectrometer, coupled with a mul-
ti-channel analyzer (a.e.n., Ponteranica (BG), Italy)
equipped with a cryostat Cryo (RIAL, Parma, Italy).
A Ca119SnO3 Mo¨ssbauer source, 10 mCi (Ritverc, St
Petersburg, Russia), moving at room temperature with
constant acceleration in a triangular waveform was
used. The velocity calibration was made using a 57Co
O
C
N
N
N
O
N
H
C
H
C
H
B
N
N
N
N
N
N
N
N
N
N
N
N
tris(pyrazolyl)alkanes bis(pyrazolyl)acetates
tris(pyrazolyl)borates
Fig. 1. The three well-known classes of scorpionate ligands.
behaving in the anionic form as N,N,O-tripodal donors,
similar to tris(pyrazolyl)borates; alternatively they may
react in the neutral form like the tris(pyrazolyl)alkanes.
Until now, all metal derivatives reported contain
bis(pyrazolyl)acetates in the anionic form [3–13]; only
a few organometallic derivatives have been reported,
limited to Nb, Re, Mn and Cr carbonyls [14–19] and a
short communication on the crystal structure of
Ph2SnBr(bdmpza) (bdmpzaH = bis(3,5-dimethylpyra-
zol-1-yl)acetic acid) [20].
Mossbauer source, 10 mCi, and an iron foil as absorber
¨
(from Ritverc, St Petersburg, Russia).
In the last few years, we have investigated the coordi-
nation chemistry of tin(IV) and organotin(IV) acceptors
with poly(azolyl)borates [21] and poly(azolyl)alkanes
[22]. Here, we report the synthesis and characterization
of new tin(IV) and organotin(IV) complexes of the
bis(pyrazolyl)acetate ligand in monoanionic and, for
the first time, also in the neutral form.
2.2. Syntheses of the complexes
2.2.1. Synthesis of [SnCy3(bpza)] (1)
A methanol solution (30 ml) containing bpzaH
(0.192 g, 1 mmol), KOH (0.056 g, 1 mmol) and Cy3SnCl
(0.219 g, 1 mmol) was stirred for 4 h at room temperature.
The solvent was removed and 20 ml chloroform was
added. The insoluble precipitate of KCl was removed
by filtration, the filtrate reduced to half volume and
40 ml of diethyl ether was added. The resulting colourless
precipitate was filtered off, washed with n-hexane (10 ml)
and dried under vacuum. The compound is soluble in
DMSO, acetone, acetonitrile and chlorinated solvents.
Yield 54%. Anal. Calcd. for C26H40N4O2Sn: C, 55.83;
H, 7.21; N, 10.02. Found: C, 55.17; H, 7.64; N, 10.01.
M.p.: 101–102 ꢁC. IR (nujol, cmꢀ1): 3104w m(Carom–H),
1664s, 1640vs masym(COO), 1514m m(C@N, C@C),
1446m msym(COO), 535m, 492m m(Sn–C), 417s, 326vs
2. Experimental
2.1. Materials and methods
All reagents were purchased from Aldrich (Milwau-
kee) and used as received. The ligands bpzaH
(bpzaH = bis(pyrazol-1-yl)acetic acid) and bdmpzaH
were prepared according to literature methods [4,15].
Solvent evaporations were carried out under vacuum
using a rotary evaporator. Samples for microanalysis
were dried in vacuo to constant weight (20 ꢁC, ca.
0.1 Torr). All syntheses were carried out under a nitrogen
atmosphere. Hydrocarbon solvents were dried by distil-
lation from sodium–potassium; dichloromethane was
distilled from calcium hydride. All solvents were de-
gassed with dry nitrogen prior to use. Elemental analyses
(C, H, N) were performed in-house with a Fisons Instru-
ments 1108 CHNS-O Elemental analyzer. IR spectra
were recorded from 4000 to 100 cmꢀ1 with a Perkin–El-
1
m(Sn–O). H NMR (acetone-d6): d 1.30, 1.65, 1.89 (m,
33H, Sn–Cy), 6.27 (t, 2H, H4), 7.03 (s, 1H, CH), 7.52 (d,
2H, H5), 7.78 (d, 2H, H3). 119Sn NMR (acetone-d6): 73.3.
2.2.2. Synthesis of [SnMe2Cl(bpza)] (2)
Compound 2 was prepared following a procedure
similar to that reported for 1, using Me2SnCl2. It is a vis-
cous oil, soluble in DMSO, acetone, acetonitrile and
chlorinated solvents. The compound is soluble in
DMSO, acetone, acetonitrile and chlorinated solvents.
Yield 65%. Anal. Calcd. for C10H13ClN4O2Sn: C,
32.00; H, 3.49; N, 14.93. Found: C, 33.19; H, 4.08; N,
13.82. M.p.: 194–197 ꢁC. IR (nujol, cmꢀ1): 3164w,
3131w, 3114w m(Carom–H), 1666vs masym(COO), 1515m
m(C@N, C@C), 1412m msym(COO), 581s, 568m, 526m
m(Sn–C), 493vs, 377s m(Sn–O), 279s, 258sh m(Sn–Cl).
1H NMR (acetone-d6): d 1.16 (s, 6H, 2J(119Sn–1H):
87.5 Hz, 2J(119Sn–1H): 84.8 Hz, Sn–Me), 6.39 (t, 2H,
H4), 7.16 (s, 1H, CH), 7.61 (d, 2H, H5), 7.76 (d, 2H,
1
mer System 2000 FT-IR instrument. H, 13C and 119Sn
NMR spectra were recorded using a VXR-300 Varian
and Bruker AC 200 spectrometers operating at room
1
temperature (respectively at 300 and 200 MHz for H,
75 and 50 MHz for 13C and 111.9 MHz for 119Sn). The
chemical shifts (d) are reported in parts per million
(ppm) from SiMe4 (1H and 13C calibration by internal
deuterium solvent lock) and SnMe4 (external). The spec-
tral width is 900 ppm (from +200 to ꢀ700 ppm). Peak

1880
F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
H3). 13C NMR (acetone-d6): d 11.08 (s, Sn–Me), 75.09
(s, CH), 106.81 (s, C4), 130.99 (s, C5), 140.52 (s, C3),
167.88 (s, COO). 119Sn NMR (acetone-d6): ꢀ295.6.
uble in dmso, acetone, acetonitrile and chlorinated sol-
vents. Yield 58%. Anal. Calcd. for C14H12Cl2N4O2Sn:
C, 36.73; H, 2.64; N, 12.24. Found: C, 36.53; H,
2.88; N, 11.95. M.p.: 168–170 ꢁC. IR (nujol, cmꢀ1):
3117w m(Carom–H), 1693vs, 1674s masym(COO), 1574m
2.2.3. Synthesis of [SnBun2Cl(bpza)] (3)
1
Compound 3 was prepared following a procedure
similar to that reported for 1, using Bun2SnCl2. It is a
viscous oil, soluble in dmso, acetone, acetonitrile and
chlorinated solvents. Yield 69%. Anal. Calcd. for
C16H25ClN4O2Sn: C, 41.82; H, 5.48; N, 12.19. Found:
C, 42.45; H, 6.02; N 11.71. IR (nujol, cmꢀ1): 3118w
m(Carom–H), 1668m, 1615s masym(COO), 1516m m(C@N,
C@C), 1411m msym(COO), 552m, 535sh m(Sn–C), 480vs
m(Sn–O), 292vs m(Sn–Cl). 1H NMR (acetone-d6): d
0.97–1.11, 1.39–1.90 (m, 18H, Sn–Bun), 6.44 (sbr, 2H,
H4); 7.22, 7.42 (s, 1H, CH); 7.65 (s, 2H, H5); 8.04,
8.08 (sbr, 2H, H3). 13C NMR (acetone-d6): d 13.98,
26.89, 27.52, 27.76 (s, Sn–Bun), 76.25 (d, CH), 107.13
(d, C4), 131.3 (s, C5), 140.83 (s, C3), 170.44 (s, COO).
119Sn NMR (acetone-d6): ꢀ195.0, ꢀ201.4.
m(C@C), 1510m m(C@N, C@C), 1408m msym(COO). H
NMR (CDCl3): d 6.37, 6.47 (t, 2H, H4), 7.35, 7.37 (s,
1H, CH), 7.55, 7.70, 8.20, 8.32 (m, 9H, H5, H3 and
Sn–Ph). 13C NMR (CDCl3): d 70.78 (s, CH), 107.90,
108.10 (s, C4), 129.04, 129.79, 130.39, 131.82, 135.34,
148.09 (s, Sn–Ph), 133.02, 133.65 (s, C5), 141.52,
141.88 (s, C3), 164.24 (s, COO). 119Sn NMR (CDCl3):
d 511.7, ꢀ522.5.
2.2.7. Synthesis of [SnCl3(bpza)] (7)
Compound 7 was prepared following a procedure
similar to that reported for 1, using SnCl4. It is soluble
in dmso, acetone, acetonitrile and chlorinated solvents.
Yield 84%. Anal. Calcd. for C8H7Cl3N4O2Sn: C,
23.09; H, 1.70; N, 13.46. Found: C, 22.99; H, 1.87; N,
12.77. M.p.: 291–292 ꢁC. IR (nujol, cmꢀ1): 3165w,
3156w, 3136w m(Carom–H), 1723s, 1696s masym(COO),
1508m m(C@N, C@C), 1412s, 1403m msym(COO), 421m
2.2.4. Synthesis of [SnPh2Cl(bpza)] (4)
Compound 4 was prepared following a procedure
similar to that reported for 1, using Ph2SnCl2. It is sol-
uble in dmso, acetone, acetonitrile and chlorinated sol-
vents. Yield 72%. Anal. Calcd. for C20H17ClN4O2Sn:
C, 48.09; H, 3.43; N, 11.22. Found: C, 47.65; H, 3.60;
N, 11.04. M.p.: 103–108 ꢁC. IR (nujol, cmꢀ1): 3122w
m(Carom–H), 1664s masym(COO), 1557m, 1512m m(C@N,
C@C), 1399m msym(COO). 1H NMR (CDCl3): d 6.34
(t, 2H, H4), 7.01 (s, 1H, CH), 7.68 (d, 2H, H5), 7.78
(d, 2H, H3), 7.34, 7.89 (m br, 10H, Sn–Ph). 13C NMR
(CDCl3): d 70.68 (s, CH), 107.36 (s, C4), 128.67,
129.38, 130.71, 136.37 (s, Sn–Ph), 134.80 (s, C5),
141.38 (s, C3), 165.74 (s, COO). 119Sn NMR (CDCl3):
d ꢀ421.2.
1
m(Sn–O), 335vs br m(Sn–Cl). H NMR (acetone-d6): d
6.99t (2H, H4); 8.02s (1H, CH); 8.48d (2H, H5); 8.70d
(2H, H3). 13C NMR (acetone-d6): d 71.32 (s, CH),
109.28 (s, 3J (Sn–C): 15.9 Hz, C4), 135.89 (s, C5),
142.39 (s, C3), 161.22 (s, COO). 119Sn NMR (acetone):
d ꢀ622.31.
2.2.8. Synthesis of [SnBr3(bpza)] (8)
Compound 8 was prepared following a procedure
similar to that reported for 1, using SnBr4. It is soluble
in dmso, acetone, acetonitrile and chlorinated solvents.
Yield 68%. Anal. Calcd. for C8H7Br3N4O2Sn: C,
17.48; H, 1.28; N, 10.19. Found: C, 18.91; H, 1.74; N
9.63. M.p.: 265–268 ꢁC. IR (nujol, cmꢀ1): 3130w,
3111w m(Carom–H), 1723s, 1695s masym(COO), 1516m,
1504m m(C@N, C@C), 1409m msym(COO), 417m, 335m
2.2.5. Synthesis of [SnBunCl2(bpza)] (5)
Compound 5 was prepared following a procedure
similar to that reported for 1, using BunSnCl3. It is sol-
uble in dmso, acetone, acetonitrile and chlorinated sol-
vents. Yield 58%. Anal. Calcd. for C12H16Cl2N4O2Sn:
C, 32.92; H, 3.68; N, 12.79. Found: C, 32.73; H, 4.05;
N, 11.94. M.p.: 211–213 ꢁC. IR (nujol, cmꢀ1): 3112w,
3094w m(Carom–H), 1694vs masym(COO), 1509s m(C@N,
C@C), 1406m msym(COO), 411m, 305vs br m(Sn–O),
1
m(Sn–O), 246vs, 236vs, 224s m(Sn–Br). H NMR (ace-
tone-d6): d 6.47 (t, 2H, H4); 7.57 (s, 1H, CH), 7.67 (d,
2H, H5), 8.07 (d, 2H, H3). 119Sn NMR (acetone-d6): d
ꢀ739.4.
2.2.9. Synthesis of [SnI3(bpza)] (9)
Compound 9 was prepared following a procedure
similar to that reported for 1, using SnI4. It is soluble
in dmso, acetone, acetonitrile and chlorinated solvents.
Yield 55%. Anal. Calcd. for C8H7I3N4O2Sn: C, 13.91;
H, 1.02; N, 8.11. Found: C, 14.00; H, 0.99; N, 7.93.
1
229s m(Sn–Cl). H NMR (acetone-d6): d 0.92t, 1.42m,
1.82m (9H, Sn–Bun), 6.73 (t, 2H, H4), 7.73s (1H, CH),
8.24 (d, 2H, H5), 8.41 (d, 2H, H3). 13C NMR (acetone-
d6): d 13.88, 26.06, 26.08, 28.21 (s, Sn–Bun), 71.68 (s,
CH), 108.40 (s, C4), 134.39 (s, C5), 142.15 (s, C3),
158.80 (s, COO). 119Sn NMR (acetone-d6): d ꢀ473.7.
M.p.: 254–256 ꢁC. IR (nujol, cmꢀ1): 3140w m(Carom
–
H), 1664s br masym(COO), 1513m m(C@N, C@C),
1407m msym(COO), 410s m(Sn–O), 212sh, 204vs m(Sn–I).
1H NMR (acetone-d6): d 6.84t (2H, H4); 7.85s (1H,
CH); 8.38d (2H, H5); 8.48d (2H, H3). 13C NMR (ace-
tone-d6): d 71.1 (s, CH), 108.1 (s, C4), 135.5 (s, C5),
2.2.6. Synthesis of [SnPhCl2(bpza)] (6)
Compound 6 was prepared following a procedure
similar to that reported for 1, by using PhSnCl3. It is sol-

F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
1881
140.3 (s, C3), 160.8 (s, COO). 119Sn NMR (acetone-d6): d
ꢀ831.9.
and 5-Me); 6.01s, 6.32s, 7.22s (2H, H4); 6.84s, 6.88s
(1H, CH). 13C NMR (acetone-d6): d 10.84, 10.88 (s,
Sn–Me), 13.58, 14.85, 19.93, 24.17 (s, 3-Me e 5-Me),
65.67 (s, CH), 109.30, 109.60 (s, C4), 143.65, 144.04 (s,
C5), 151.92, 153.05 (s, C3), 161.50, 162.73 (s, COO).
119Sn NMR (acetone-d6): d ꢀ472.4, ꢀ479.8.
2.2.10. Synthesis of [SnMe2Cl(bdmpza)] (10)
Compound 10 was prepared following a procedure
similar to that reported for 1, using Me2SnCl2. It is sol-
uble in dmso, acetone, acetonitrile and chlorinated sol-
vents. Yield 62%. Anal. Calcd. for C14H21ClN4O2Sn:
C, 38.97; H, 4.91; N, 12.98. Found C, 38.61; H, 5.41;
N, 11.82. M.p.: 193–195 ꢁC. IR (nujol, cmꢀ1): 3120w
m(Carom–H), 1681s, 1612s masym(COO), 1554s m(C@N,
C@C), 1410m msym(COO), 584m, 574m, 528m m(Sn–C),
488s, 349s m(Sn–O), 277s, 255s m(Sn–Cl). 1H NMR (ace-
2.2.13. Synthesis of [SnPhCl2(bdmpza)] (13)
Compound 13 was prepared following a procedure
similar to that reported for 5, using PhSnCl3. Yield
59%. Anal. Calcd. C18H20Cl2N4O2Sn: C, 42.06; H,
3.92; N, 10.90. Found: C, 41.72; H, 4.01; N, 10.65.
M.p.: 252–254 ꢁC. IR (nujol, cmꢀ1): 3138w, 3066w,
3034w m(Carom–H), 1686vs, 1637m masym(COO), 1573w,
1557s m(C@N, C@C), 1430m, 1418m msym(COO), 343vs
br m(Sn–O), 281s m(Sn–Cl), 246s, 228s m(Sn–C). 1H
NMR (acetone-d6): d 1.87, 1.89, 2.68, 2.71, 2.80, 2.83
(s, 12H, 3-Me and 5-Me); 6.24, 6.30, 6.37 (s, 2H, H4);
6.97, 7.01 (s, 1H, CH); 7.45, 7.75 (m, 5H, Sn–Ph). 13C
NMR (acetone-d6): d 11.00, 11.09, 11.16, 13.31, 13.47,
14.98 (s, 3-Me and 5-Me), 65.93 (s, CH), 109.41,
109.52, 109.94 (s, C4), 144.17, 144.43, 144.67 (s, C5),
152.77, 153.11, 153.37 (s, C3), 129.19, 129.52, 130.24,
130.56, 134.00, 134.39, 150.08, 150.20 (s, Sn–Ph),
163.32 (s, COO). 119Sn NMR (acetone-d6): d ꢀ524.2,
ꢀ541.1.
tone-d6):
d
1.11 (s, 3H, 2J(119Sn–1H): 83.3 Hz,
2J(119Sn–1H): 80.1 Hz, Sn–Me), 1.25, 1.41 (s, 3H, Sn–
Me) 2.09, 2.18, 2.19, 2.32 (s, 12H, 3-Me and 5-Me),
5.85, 5.94 (s, 2H, H4), 6.93, 7.15 (s, 1H, CH). 1H
NMR (CDCl3): d 0.98 (s, 3H, J(119Sn–1H): 71.8 Hz,
2
2J(119Sn–1H): 67.3 Hz, Sn–Me), 2.32, 2.36 (s, 12H, 3-
Me and 5-Me); 5.92 (s, 2H, H4); 6.56 (s, 1H, CH). 13C
NMR (acetone-d6): d 11.10 (s, Sn–Me), 11.85, 13.50 (s,
3-Me and 5-Me), 71.20 (s, CH), 107.71 (s, C4), 141.93
(s, C5), 148.84 (s, C3), COO not observed. 119Sn NMR
(CDCl3): d,ꢀ281. 119Sn NMR (acetone-d6): d ꢀ295.2.
2.2.11. Synthesis of [SnPh2Cl(bdmpza)] (11)
Compound 11 was prepared following a procedure
similar to that reported for 5, using Ph2SnCl2. Yield
63%. Anal. Calcd. for C24H25ClN4O2Sn: C, 51.88; H,
4.54; N, 10.08. Found: C, 51.54; H, 4.70; N, 10.08.
M.p.: >350 ꢁC. IR (nujol, cmꢀ1): 3127w, 3064w,
3033w (Carom–H), 1690vs, 1674s masym(COO), 1576m,
1557s m(C@N, C@C), 1429s, 1415m msym(COO), 449s
m(Sn–O), 291vs m(Sn–Cl), 264vs, 246vs m(Sn–C). 1H
NMR (acetone-d6): d 1.71br, 2.04, 2.78br, 2.96 (s,
12H, 3-Me and 5-Me), 6.25br, 6.28 (s, 2H, H4); 7.04s
(1H, CH); 7.50, 7.76, 7.92 (mbr, 10H, Sn–Ph). 13C
NMR (acetone-d6): d 13.61, 14.02 (s, 3-Me and 5-Me),
66.28 (s, CH), 108.93 (s, C4), 135.85 (s, C5), 152.03 (s,
C3), 128.88, 129.35, 135.51, 152.00 (s, Sn–Ph), 162.73
(s, COO). 119Sn NMR (acetone-d6): d ꢀ451.7, ꢀ457.7.
2.2.14. Synthesis of [SnCl3(bdmpza)] (14)
Compound 14 was prepared following a procedure
similar to that reported for 5, using SnCl4. It is soluble
in dmso, acetone, acetonitrile and chlorinated solvents.
Yield 74%. Anal. Calcd. for C12H15Cl3N4O2Sn: C,
30.52; H, 3.20; N, 11.86. Found: C, 30.77; H, 3.41; N,
11.80. M.p.: 292–293 ꢁC. IR (nujol, cmꢀ1): 3144w,
3138w m(Carom–H), 1724sbr masym(COO), 1555s m(C@N,
C@C), 1415s msym(COO), 427m m(Sn–O), 348vs, 333vs,
1
321vs m(Sn–Cl). H NMR (acetone-d6): d 2.68, 2.71 (s,
12H, 3-Me and 5-Me); 6.42 (s, 2H, H4); 7.06 (s, 1H,
CH). 13C NMR (acetone-d6): d 11.11, 14.23 (s, 3-Me
and 5-Me), 65.49 (s, CH), 110.05 (s, C4), 145.42 (s,
C5), 153.47 (s, C3), 161.38 (s, COO). 119Sn NMR (ace-
tone-d6): d ꢀ636.7.
2.2.12. Synthesis of [SnMeCl2(bdmpza)] (12)
Compound 12 was prepared following a procedure
similar to that reported for 1, using MeSnCl3. The com-
pound is soluble in dmso, acetone, acetonitrile and chlo-
rinated solvents. Yield 53%. Anal. Calcd. for
C13H18Cl2N4O2Sn: C, 34.55; H, 4.01; N, 12.40. Found:
C, 34.03; H, 4.33; N, 11.71. M.p.: 249–250 ꢁC. IR (nujol,
cmꢀ1): 3134w, 3091w m(Carom–H), 1694vs masym(COO),
1562s m(C@N, C@C), 1420m msym(COO), 539s m(Sn–C),
422m m(Sn–O), 307vsbr m(Sn–Cl). 1H NMR (acet-
one-d6): d, 1.17 (s, 3H, 2J(119Sn–1H): 121.9 Hz,
2J(119Sn–1H): 117.5 Hz, Sn–Me), 1.44 (s, 3H,
2J(119Sn–1H): 126.3 Hz, 2J(119Sn–1H): 119.4 Hz, Sn–
Me), 2.17, 2.35, 2.53, 2.55, 2.65, 2.73 (s, 12H, 3-Me
2.2.15. Synthesis of [SnBr3(bdmpza)] (15)
Compound 15 was prepared following a procedure
similar to that reported for 5, using SnBr4. Yield 83%.
Anal. Calcd. for C12H15Br3N4O2Sn: C, 23.80; H, 2.50;
N, 9.25. Found: C, 24.08; H, 2.61; N, 9.18. M.p.: 266–
268 ꢁC. IR (nujol, cmꢀ1): 3135w m(Carom–H), 1697vs br
m
asym(COO), 1559s m(C@N, C@C), 1418m msym(COO),
1
425s m(Sn–O), 231vsbr, 210sh m(Sn–Br). H NMR (ace-
tone-d6): d 2.72, 2.79 (s, 12H, 3-Me and 5-Me), 6.41 (s,
2H, H4), 7.04 (s, 1H, CH). 13C NMR (acetone-d6): d
11.52, 15.14 (s, 3-Me and 5-Me), 65.76 (s, CH), 110.77
(s, C4), 145.48 (s, C5), 153.66 (s, C3), 161.91 (s, COO).
119Sn NMR (acetone-d6): d ꢀ770.7.

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F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
Table 1
Selected molecular geometries, [SnI3(bdmpza)] (16)
2.2.16. Synthesis of [SnI3(bdmpza)] (16)
Compound 16 has been prepared following a proce-
dure similar to that reported for 1. It is soluble in dmso,
acetone, acetonitrile and chlorinated solvents. Yield
67%. Anal. Calcd. for C12H15N4O2I3Sn: C, 19.30; H,
2.02; N, 7.50%. Found: C, 18.56; H, 2.17; N, 6.18%.
Atoms
Parameter
˚
Distances (A)
Sn–I(1)
Sn–I(2)
Sn–I(3)
2.7521(3)
2.7754(3)
2.7711(3)
1.302(3)
2.260(2)
2.270(2)
2.087(2)
1.213(4)
M.p.: 246–247 ꢁC. IR (nujol, cmꢀ1): 3127w m(Carom
–
C(32)–O(31)
Sn–N(11)
Sn–N(21)
Sn–O(31)
C(32)–O(32)
H), 1715vs br masym(COO), 1556s m(C@N, C@C),
1
1414m msym(COO), 421w m(Sn–O). H NMR (acetone-
d6): d 2.19s, 2.36s, 2.85s, 3.07s (12H, 3-Me e 5-Me);
6.03s, 6.47s (2H, H4); 7.10s, 7.33s (1H, CH). 13C
NMR (acetone-d6): d 10.8, 11.1, 13.4, 14.8 (s, 3-Me e
5-Me), 64.9, 72.7 (s, CH), 107.3, 110.6 (s, C4), 129.5,
129.7, 144.1 (s, C5), 132.7, 133.3, 152.4 (s, C3), 161.7
(s, COO). 119Sn NMR (acetone-d6): d ꢀ864.4.
Angles (ꢁ)
I(1)–Sn–I(2)
98.06(1)
95.18(1)
96.39(1)
81.04(8)
81.90(8)
81.22(8)
89.53(5)
160.49(6)
118.2(1)
136.0(2)
119.4(2)
129.1(2)
90.49(5)
168.22(6)
90.74(6)
90.26(7)
170.18(6)
92.15(5)
90.11(5)
110.0(2)
117.3(2)
136.9(2)
120.2(2)
128.1(2)
126.0(2)
I(1)–Sn–I(3)
I(2)–Sn–I(3)
N(11)–Sn–N(21)
N(11)–Sn–O(31)
N(21)–Sn–O(31)
I(1)–Sn–O(31)
I(2)–Sn–O(31)
Sn–N(11)–N(12)
Sn–N(11)–N(15)
C(0)–N(12)–N(11)
C(0)–N(12)–C(13)
I(1)–Sn–N(11)
I(1)–Sn–N(21)
I(2)–Sn–N(11)
I(2)–Sn–N(21)
I(3)–Sn–N(11)
I(3)–Sn–N(21)
I(3)–Sn–O(31)
N(12)–C(0)–N(22)
Sn–N(21)–N(22)
Sn–N(21)–N(25)
C(0)–N(22)–N(21)
C(0)–N(22)–N(23)
Sn–O(31)–C(32)
2.2.17. Synthesis of [SnBunCl3(bpzaH)] (17)
BunSnCl3 (0.282 g, 1 mmol) was added to a diethyl
ether solution (30 ml) of bpzaH (0.192 g, 1 mmol).
The reaction mixture was stirred to room temperature
and a colourless precipitate slowly afforded. After 48 h
it was filtered off, washed with n-hexane (10 ml) and
dried to constant weight under reduced pressure. The
compound is soluble in dmso acetone, acetonitrile and
chlorinated solvents. Yield 54%. Anal. Calcd. for
C12H17Cl3N4O2Sn: C, 30.39; H, 3.61; N, 11.81. Found:
C, 30.58; H, 3.79; N, 11.52%. M.p.: 198–200 ꢁC. IR (nu-
jol, cmꢀ1): 3113s, 3078m m(Carom–H), 1692vs, 1669s
m
asym(COO), 1509m m(C@N, C@C), 1406s msym(COO),
306vs br m(Sn–Cl). 1H NMR (acetone-d6): d 0.92t,
1.45m, 1.78m (9H, Sn–Bun); 6.35, 6.73, 6.85 (t, 2H,
H4), 7.42, 7.63, 7.88 (s, 1H, CH), 7.55, 8.25, 8.35 (d,
2H, H5), 7.98, 8.40, 8.58 (d, 2H, H3). 13C NMR (ace-
tone-d6): d 13.9, 26.1, 28.2 (s, Sn–Bun), 71.7, 74.9, 86.5
(s, CH), 107.3, 108.4, 109.1 (s, C4), 131.3, 140.9 (s,
C5), 134.4, 142.2 (s, C3), 162.2 (s, COO). 119Sn NMR
(acetone-d6): d ꢀ473.6 br.
Torsion angles (ꢁ)
N(21)–Sn–N(11)–N(12)
Sn–N(11)–N(12)–C(0)
N(11)–N(12)–C(0)–N(22)
Sn–O(31)–C(32)–C(0)
N(11)–Sn–N(21)–N(22)
Sn–N(21)–N(22)–C(0)
N(21)–N(22)–C(0)–N(12)
40.1(2)
3.9(3)
ꢀ67.4(3)
9.1(3)
ꢀ42.2(2)
0.6(3)
64.6(3)
2.2.18. Synthesis of [SnPhCl3(bpzaH)] (18)
The tin atom lies 0.111(5), 0.082(5) out of the N2C3 ring planes (v2 9.6,
18.8; interplanar dihedral angle 64.5(1)ꢁ) and 0.319(6) A out of the
CO2 plane, dihedral angles of the latter to the C3N2 planes being
Compound 18 was prepared following a procedure
similar to that reported for 17, using PhSnCl3. It is sol-
uble in dmso, acetone, acetonitrile and chlorinated sol-
vents. Yield 46%. Anal. Calcd. for C14H13Cl3N4O2Sn:
C, 34.02; H, 2.65; N, 11.33. Found: C, 34.53; H, 2.72;
N, 11.13%. M.p.: 145–150 ꢁC. IR (nujol, cmꢀ1):
3175w, 3091w (Carom–H), 1723s, 1674s masym(COO),
1504m m(C@N, C@C), 1403m msym(COO), 310vs br
˚
64.9(3), 51.1(3)ꢁ.
2.2.19. Synthesis of [SnCl4(bpzaH)] (19)
Compound 19 was prepared following a procedure
similar to that reported for 17, using SnCl4 Æ 5H2O. It
is soluble in dmso, acetone, acetonitrile and chlorinated
solvents. Yield 68%. Anal. Calcd. for C8H8N4O2Cl4Sn:
C, 21.23; H, 1.78; N, 12.38. Found: C, 21.58; H, 1.92;
N, 12.03%. M.p.: 269–271 ꢁC. IR (nujol, cmꢀ1):
3155w, 3126w, 3110w m(Carom–H), 1724vs br
1
m(Sn–Cl), 262s, 231m m(Sn–C). H NMR (acetone-d6):
d 6.33, 6.44 (t, 2H, H4), 7.19, 7.24 (s, 1H, CH), 7.58,
7.66 (d, 2H, H5), 7.81, 8.04 (d, 2H, H3), 7.45, 7.84,
8.18 (m, 5H, Sn–Ph). 13C NMR (acetone-d6): d 72.2,
79.6 (s, CH), 107.9, 108.9, 109.2 (s, C4), 129.8, 134.9
(s, C5), 128.4, 129.2, 131.7, 141.5, 142.7, 142.9, 150.2
(s, Sn–Ph), 131.0, 135.4 (s, C3), 163.2 (s, COO). 119Sn
NMR (acetone-d6): d ꢀ528.9.
m
asym(COO), 1510m m(C@N, C@C), 1410s msym(COO),
336vs br m(Sn–Cl). 1H NMR (acetone-d6): d 6.99 (t,
2H, H4), 8.02s (1H, CH), 8.11 (d, 2H, H5), 8.69 (d,

F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
1883
2H, H3). 13C NMR (acetone-d6): d 71.2 (s, CH), 109.1 (s,
C4), 135.6 (s, C5), 142.2 (s, C3), 161.0 (s, COO). 119Sn
NMR (acetone-d6): d ꢀ621.5.
l
Mo = 5.5 mmꢀ1
0T0min/max = 0.59.
;
specimen: 0.45 · 0.37 · 0.24 mm;
3. Results and discussion
2.3. Structure determination
3.1. Syntheses
A full sphere of ꢀlowꢁ-temperature CCD area-detector
diffractometer data was measured (Bruker AXS
instrument, monochromatic Mo Ka radiation,
The tin complexes 1–16 were prepared by reaction of
the bis(pyrazolyl)acetate ligand with the appropriate
tin(IV) or organotin(IV) acceptor in methanol in the
presence of potassium hydroxide (Schemes 1 and 2).
The derivatives 1–16 are reasonably stable in air, and
in acetonitrile, acetone, and chlorinated solvents, where
they are non-electrolytes, as well as in the solid state.
However, prolonged warming and/or storage under re-
duced pressure appears to induce some decomposition
process via decarbonylation, with the release of CO2
and the formation of a mixture of pyrazole-containing
metal complexes and other unidentified products.
˚
k = 0.71073 A; x-scans; 2hmax = 75ꢁ; T ca. 153 K) yield-
ing 21562 reflections, these merging to 10880 unique
(Rint 0.026) after ꢀempiricalꢁ/multiscan absorption cor-
rection (proprietary software), 10047 with F > 4r(F)
considered ꢀobservedꢁ and used in the full matrix least
squares refinements, refining anisotropic displacement
parameter forms for the non-hydrogen atoms, (x,y,z,
Uiso)H constrained at estimates. Difference map residues
were modelled in terms of solvate acetonitrile, atom
assignment being based on refinement behaviour and
location of the hydrogen atoms in difference maps. Con-
ventional residuals on |F| at convergence were R = 0.031,
Rw = 0.049 (reflection weights: (r2(F) + 0.0008F2)ꢀ1).
Neutral atom complex scattering factors were employed
within the Xtal 3.7 program system [23]. Pertinent re-
sults are given below and in Table 1 and Fig. 4, the latter
showing non-hydrogen displacement amplitudes at the
50% probability level, hydrogen atoms having arbitrary
3.2. Spectroscopy
Infrared spectra, measured on the solid samples (nu-
jol, mull), showed all the expected bands for the ligand
and the tin moieties: weak absorptions near 3100 cmꢀ1
are due to the pz ring Carom–H stretching, and medium
to strong absorptions in the range 1500–1560 cmꢀ1 are
related to ring ‘‘breathing’’ vibrations. The presence of
the COO moiety is indicated by strong masym(COO)
bands in the range 1610–1770 cmꢀ1, a red shift relative
to the free neutral ligands being observed upon complex
formation [3–20]. This is in keeping with an electron
flow from the ligand toward the tin moiety, with conse-
quent decreasing C@O bond order. Further, the pres-
ence of a msym(COO) in the range 1400–1450 cmꢀ1 was
always detected. The difference Dm = masym(COO) ꢀ
˚
radii of 0.1 A. Full details (excluding structure factor
amplitudes) are deposited with the Cambridge Struc-
tural Database, CCDC 258719.
2.3.1. Crystal data
C12H15I3N4O2Sn. CH3CN,Mr = 787.8. Triclinic, space
1
ꢀ
group P1 (Ci , No. 2), a = 7.9048(6), b = 10.4369(8),
˚
A,
c = 13.719(1)
a = 99.751(2),
b = 103.508(ꢀ23),
3
˚
c = 95.395(2)ꢁ, V = 1074 A . Dc (Z = 4) = 2.436 g cm
.
O
O
C
O
C
OH
MeOH
H
C
H
C
SnRnX4-n KOH
N
N
N
N
N
N
SnRnX3-n
N
N
1, R = Cy,n = 3, X = Cl
2, R = Me,n = 2, X = Cl
n
Cl
Cl
Cl
Cl
3, R = Bu ,n = 2,X =
4, R = Ph, n = 2, X =
n
5, R = Bu ,n = 1,X =
6, R = Ph,n = 1, X =
7, n = 0, X = Cl
8, n = 0, X = Br
9, n = 0, X = I
Scheme 1.

1884
F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
O
C
O
C
OH
N
O
MeOH
H
C
H
C
SnRnX4-n KOH
N
N
N
N
N
SnRnX3-n
N
N
10, R = Me, n = 2, X = Cl
11, R = Ph, n = 2, X= Cl
12, R =Me, n = 3, X = Cl
13, R = Ph, n = 3, X = Cl
14, n = 0, X = Cl
15, n = 0, X = Br
16, n = 0, X = I
Scheme 2.
m
sym(COO) is always higher than 200 cmꢀ1, in accor-
of 1, 7–9 and 14–16, only one geometrical isomer being
possible. When both R and X groups are bonded to the
metal atom, as alkyls and chlorine, two different geomet-
rical isomers are possible in solution (Fig. 2). In fact, in
dance with a unidentate COO moiety [24]. In the far-
IR region medium to strong absorptions appear upon
coordination, arising from the stretching modes of Sn–
O [24], Sn–R [25–29] and Sn-halide components [24].
In the IR spectra of 1–16, single absorptions assigned
to Sn–O have been detected between 350 and 430
cmꢀ1. Trends have been found for the m(Sn–O) mode,
the replacement of R groups with chlorine increasing
its absorption frequency. Moreover, m(Sn–O) decreases
in the order: Cl > Br > I, respectively. These trends can
be easily explained on the basis of the higher inductive
effect of the electron-withdrawing chlorine relative to
alkyls and other halides, with concomitant strengthen-
ing of the Sn–O bond [24].
1
the H NMR spectra of derivatives 3, 6, 11, 12 and 13,
two or three sets of signals are generally observed for
the protons of bpza and bdmpza and two sets for the
protons of alkyl groups bonded to the tin, in accordance
with the existence of the complexes in both the isomeric
forms. By contrast in the 1H NMR spectra of 2, 4, 5 and
10, only one set of resonances has been observed, all
ascribable to the trans isomer. In all cases the resonances
of the ligand protons are deshielded upon coordination.
In the spectra of the dimethyltin-derivatives 2 and 10
and the methyltin derivative 12 it has been possible to
2
The proton NMR spectra show all the expected reso-
nances for the tripodal ligands and the tin moieties. A
1
unique set of signals is found in the H NMR spectra
detect JSn–H coupling constants; they lie in the ranges
80–90 and 117–121 Hz, respectively, somewhat higher
than those observed for the analogous methyltin-
tris(pyrazolyl)borates [21].
119Sn NMR data fall in the range typical for octahe-
dral tin species, showing more resonances in the case of
derivatives 3, 6, 11, 12 and 13, in accordance with the
presence of a mixture of isomers in solution [30,31], indi-
cating further some progressive decomposition process
to be operating in solution. After some days the initial
resonances decrease in intensity, with new signals
appearing in the range of ꢀ200/ꢀ350 ppm, presumably
due to the dissociation of the ligand and the formation
O
O
N
H
H
O
Sn
R
O
Sn
X
N
N
N
N
X
R
N
R
R
N
N
SnR2X(bpza)
H
of solvated tin species such as (acetone)3SnRnCl3 ꢀ n
.
We have also studied the direct interaction of bpzaH
with some tin acceptors as BunSnCl3, PhSnCl3 and
SnCl4 in Et2O, in the absence of base; the 1:1 adducts
17–19 have been isolated (Scheme 3). They are air stable
solids soluble in acetone, acetonitrile and dmso. Their
IR spectra indicate that the carboxylate is not coordi-
nated to the tin, as the masym(COO) is not shifted with
respect to free neutral bpzaH ligand. Moreover, no
m(Sn–O) has been detected in the far-IR region. The pro-
ton NMR spectra of derivatives 17 and 18 show three
and two sets of resonances, respectively, due to the pres-
ence of two isomers in solution (Scheme 4).
O
O
H
O
O
N
N
N
N
N
X
N
X
Sn
X
Sn
R
N
R
N
X
SnRX2(bpza)
Fig. 2. Possible isomers for [SnR2X(L)] and [SnRX2(L)] complexes.

F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
1885
HO
However, in the 119Sn NMR spectra only broad res-
onances have been detected. In acetone solution deriva-
tive 19 slowly undergoes partial dissociation with the
formation of the initial neutral free bpzaH and solvated
O
Cl
Sn
R
H
Cl
Cl
Et2O
N
1
N
bpzaH + RSnCl3
(acetone)2SnCl4 (Scheme 5). In fact, the H NMR spec-
N
N
trum in deuteroacetone shows two sets of resonances,
one of which is due to free bpzaH and the other assign-
able to coordinated bpzaH, a downfield shift being ob-
served both for the pz protons and for the bridging CH.
The experimental 119Sn Mo¨ssbauer spectra are of
three distinct types (Fig. 3): (i) a single absorption in
each of the complexes SnX3-ligand 7, 9, 14, 15 16; or
(ii) a well resolved doublet in each of the SnRX2-ligand
and SnR2X-ligand 3, 5, 6, 10, 11, 13 complexes; or (iii) a
spectrum with two asymmetric absorptions in each of
[SnCy3(bpza)] (1) and [SnPh2Cl(bpza)] (4). In these lat-
ter complexes the fits of the spectra are consistent with
the presence of two doublets with different parameters
and resonant area. The 1H and 119Sn NMR results indi-
cate the presence of only one octahedral geometry in 1,
but the Mo¨ssbauer data, in the solid, point to two differ-
ent Sn(IV) sites: the doublet with larger d, D, C and A%
parameters, Table 2, can be associated with an octahe-
dral geometry, unusual in R3Sn complexes, while
the 2.87 mm/s quadrupole splitting value should be
17, R = Bun
18, R = Ph
19, R = Cl
Scheme 3.
HO
HO
O
O
Cl
Cl
H
H
Cl
R
N
Cl
Cl
N
N
N
Sn
N
Sn
N
N
N
Cl
R
17, R = Bun
18, R = Ph
Scheme 4.
HO
HO
O
O
Cl
Cl
H
H
Cl
Cl
Cl
Cl
N
S
S
N
N
N
Sn
Sn
Cl
S = acetone
N
N
acetone
N
N
Cl
Scheme 5.
Fig. 3. The Mo¨ssbauer spectra of (a): [SnI3(bdmpza)] (16) and (b): [SnCy3(bpza)] (1).

1886
F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
Table 2
Mo¨ssbauer data
very large C–Sn–C angle respect to a regular geometry
can be inferred from the high D value in Alk2–SnCl moi-
eties. The spectra of [SnX3(bdmpza)] 14 and 16 may be
fitted as two line spectra with quadrupole splitting val-
ues 0.51 and 0.78 mm/s, respectively. The observed D
values can arise from a distortion from ideal Oh symme-
try arising from the steric demand of the ligand or a dif-
ferent electron withdrawal of the N,N0,O ligand atoms
respect to the halides. In the compounds 7, 9, and 15,
single absorption lines indicate a minor degree of distor-
tion respect to regular octahedral geometry.
c
Compounds
da,b
(mm/s)
Db
(mm/s)
C
(mm/s)
A%d
[SnCy3(bpza)] (1)
1.52
1.67
1.41
0.68
0.93
0.89
0.78
0.32
0.89
1.36
0.89
0.76
0.23
0.53
0.42
2.87
3.61
0.74
0.90
0.85
0.80
0.94
0.97
0.94
1.05
1.03
1.04
0.87
1.04
1.22
0.98
1.00
35
65
½SnBun2ClðbpzaÞꢂ ð3Þ
[SnPh2Cl(bpza)] (4)
3.32
1.68
100
13
2.35
1.77
87
[SnBunCl2(bpza)] (5)
[SnPhCl2(bpza)] (6)
[SnCl3(bpza)] (7)
100
100
100
100
100
100
100
100
100
100
1.63
Singlet
Singlet
3.57
[SnI3(bpza)] (9)
[SnMe2Cl(bdmpza)] (10)
[SnPh2Cl(bdmpza)] (11)
[SnPhCl2(bdmpza)] (13)
[SnCl3(bdmpza)] (14)
[SnBr3(bdmpza)] (15)
[SnI3(bdmpza)] (16)
a
2.13
1.71
3.3. X-ray single crystal study
0.51
Singlet
0.78
The results of the ꢀlowꢁ-temperature single crystal
X-ray study of 16, crystallized from acetonitrile solu-
tion, are consistent with its formulation in terms of stoi-
chiometry and connectivity as 16.CH3CN, one such
formula unit, devoid of crystallographic symmetry,
comprising the asymmetric unit of the structure. The
solvent molecule is well-defined (C–N, C(H3) 1.148(7),
With respect to R.T. spectrum of CaSnO3.
0.01 mm sꢀ1
b
c
.
Full-width at half-maximum.
Percentage area.
d
ꢁ
˚
^
preferably associated with the mer-R3TBP structure
[21,32]. In complex 4 the two doublets highlight the
presence of a pair of octahedral cis-R2 isomers in a ratio
of about 7:1, as showed in Fig. 2. In the compounds 3, 5,
6, 10, 11, and 13, in each, a single doublet, with C val-
ues in the range 0.85–1.04 mm/s, is consistent with an
octahedral arrangement for all the derivatives, but a
1.454(7) A, C–C–N 177:6ð6Þ ), but appears to have no
intimate interactions with the 16 substrate. Within the
molecule of 16 (Fig. 4) the ligand is fac-N,N0,O-triden-
tate, the three iodine atoms thus also fac about the
six-coordinate tin(IV) atom. Despite the six-membered
rings formed by the tridentate, the angles subtended
by it at the tin are diminished well below 90ꢁ, and
Fig. 4. A single molecule of [SnI3(bdmpza)] (16).

F. Marchetti et al. / Journal of Organometallic Chemistry 690 (2005) 1878–1888
1887
Chemistry II, 1, Elsevier Pergamon, Oxford, UK, 2004, pp. 159–
210 (Chapter 1.10).
remarkably similar (81.04(8)–81.90(8)ꢁ), despite a sub-
stantial difference in the interactions of the two nitrogen
atoms, cf. the oxygen at the tin, the latter difference also
showing no appreciable trans-effect within the associated
Sn–I distances.
The present appears to be the second structurally
characterized bis(pyrazolyl)acetato (tridentate) complex
of a tetravalent group 14 species, the other being
[Ph2SnBr(bdmpza)] [20], mononuclear with six-coordi-
nate tin, with the pair of phenyl groups cis, and Cl trans
[3] A. Otero, J. Fernandez-Baeza, A. Antinolo, F. Carrello-Hermo-
silla, J. Tejeda, E. Diez-Barra, A. Lara-Sanchez, L. Sanchez-
Barba, I. Lopez-Solera, Organometallics 20 (2001) 2428.
[4] A. Beck, B. Weibert, N. Burzlaff, Eur. J. Inorg. Chem. (2001) 521.
[5] B.S. Hammes, M.T. Kieber-Emmons, J.A. Letizia, Z. Shirin, C.J.
Carrano, L.N. Zakharov, A.L. Rheingold, Inorg. Chim. Acta 346
(2002) 227.
[6] A. Otero, J. Fernandez-Baeza, A. Antinolo, F. Carrello-Hermo-
silla, J. Tejeda, A. Lara-Sanchez, L. Sanchez-Barba, M. Fernan-
dez-Lopez, A.M. Rodriguez, I. Lopez-Solera, Inorg. Chem. 41
(2002) 5193.
˚
to O (Sn–O, N2 2.137(3); 2.314(4), 2.399(3) A). Numer-
[7] A. Lopez-Hernandez, R. Muller, H. Kopf, N. Burzlaff, Eur. J.
¨
Inorg. Chem. (2002) 671;
ous fac-SnI3 systems have been defined, a number oligo-
nuclear with bridging associations which essentially
constitute a tripod ligand; a number of tris(pyrazolyl)-
N3 complexes of the form {N3}SnX3 have been defined
for X = Cl [21,33–36], only one example for X = Br [22],
and seemingly no other iodides. Of relevance also is the
complex of a highly hindered N,N0-disubstituted bis-imi-
no-acetylacetonate N2SnI3, which, with a planar N,N0-
donor six-membered chelate, is five-coordinate [37].
L.-F. Tang, Z.-H. Wang, J.-F. Chai, J.-T. Wang, J. Chem.
Crystallogr. 32 (2002) 261.
[8] B. Kozlevcar, P. Gamez, R. de Gelder, W.L. Driessen, J. Reedijk,
Eur. J. Inorg. Chem. (2003) 47;
I. Hegelmann, N. Burzlaff, Eur. J. Inorg. Chem. (2003) 409.
[9] A. Beck, A. Barth, E. Huebner, N. Burzlaff, Inorg. Chem. 42
(2003) 7182.
[10] B.S. Hammes, M.T. Kieber-Emmons, J.A. Letizia, Z. Shirin, C.J.
Carrano, L.N. Zakharov, A.L. Rheingold, Inorg. Chim. Acta 346
(2003) 227.
[11] R. Mueller, E. Huebner, N. Burzlaff, Eur. J. Inorg. Chem. (2004)
2151.
[12] A. Otero, J. Fernandez-Baeza, A. Antinolo, J. Tejeda, A. Lara-
Sanchez, L. Sanchez-Barba, A.M. Rodriguez, Eur. J. Inorg.
Chem. (2004) 260.
4. Conclusions
In this work, we have prepared and characterized,
through a variety of techniques, 16 new heteroscorpio-
nate-containing tin and organotin(IV) complexes,
[SnRnX3 ꢀ n(L)]. Three 1:1 adducts [RSnCl3(bpzaH)]
were also obtained when the reaction between the ligand
and the organotin(IV) acceptors was carried out in
diethyl ether in the absence of base. The X-ray single
crystal study of [SnI3(bdmpza)] show the ligand to coor-
dinate to the tin in a fac-N,N0,O-tridentate form, in that
complex.
119Sn Mo¨ssbauer data confirm six-coordinate octahe-
dral tin sites in all the examined complexes studied save
the complex [SnCy3(bpza)] (1), where the presence of
two different geometries is suggested: one with a six-
coordinated tin atom, and the other with mer-R3 TBP
structure.
[13] A. Otero, J. Fernandez-Baeza, A. Antinolo, J. Tejeda, A. Lara-
Sanchez, L. Sanchez-Barba, M. Fernandez-Lopez, I. Lopez-
Solera, Inorg. Chem. 43 (2004) 1350.
[14] A. Otero, J. Fernandez-Baeza, J. Tejeda, A. Antinolo, F.
Carrello-Hermosilla, E. Diez-Barra, A. Lara-Sanchez, M. Fer-
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Organomet. Chem. 641 (2002) 134.
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Eur. J. Inorg. Chem. (2003) 339.
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Chem. Soc., Dalton Trans. (2003) 1614.
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Acknowledgements
We thank the University of Camerino, Palermo, Coo-
perlink (MIUR), and the CARIMA Foundation for
financial support.
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