Synthesis, characterization and structure of metallocene dicyanamide complexes

Article abstract of DOI:10.1016/j.ica.2004.09.030

The bis(cyclopentadienyl) complexes [Cp₂Ti(dca)]₂O and Cp₂V(dca)₂ (dca = dicyanamide) have been prepared by reaction of sodium dicyanamide with aqueous solution of titanocene dichloride and vanadocene dichloride

Full text of DOI:10.1016/j.ica.2004.09.030

Inorganica Chimica Acta 358 (2005) 814–819
www.elsevier.com/locate/ica
Note
Synthesis, characterization and structure of metallocene
dicyanamide complexes
a
Jan Honz ´ı cˇ ek , Milan Erben , Ivana C ´ı sa rˇ ov a´ , Jarom ´ı r Vinkl a´ rek
a
b
a,
*
a
ˇ
The Department of General and Inorganic Chemistry, University of Pardubice, n a´ m. Cs. legi ı´ 565, 532 10 Pardubice, Czech Republic
b
Department of Inorganic Chemistry, Charles University, Hlavova 2030, 128 40 Prague 2, Czech Republic
Received 13 April 2004; accepted 22 September 2004
Available online 22 October 2004
Abstract
The bis(cyclopentadienyl) complexes [Cp
2 2 2 2
Ti(dca)] O and Cp V(dca) (dca = dicyanamide) have been prepared by reaction of
sodium dicyanamide with aqueous solution of titanocene dichloride and vanadocene dichloride, respectively. The X-ray structure
analyses of both complexes confirmed monodentate coordination of dicyanamide ligand through the terminal nitrogen atom of
cyano group.
ꢀ
2004 Elsevier B.V. All rights reserved.
Keywords: Titanocene; Vanadocene; Pseudohalide; Dicyanamide complexes; X-ray structure; NMR spectroscopy; EPR spectroscopy;
Mass spectrometry
1
. Introduction
mine the bonding mode of the dicyanamide ligand in
this type of complexes.
The syntheses and characterization of metallocene
5
pseudohalide complexes of g -Cp MX (M = Ti, V;
2
2
X = NCO, NCS, NCSe, N , CN) type have been subject
2. Results and discussion
3
of several studies [1–4]. The molecular structures of
some titanocene and vanadocene complexes with linear
pseudohalide ligands have been determined by X-ray
diffraction analysis [5–11]. The bonding mode of the
pseudohalide ligand in the other complexes was identi-
fied by spectroscopic measurements, particularly by
the vibrational spectroscopy.
The title compounds [Cp Ti(dca)] O (1) and
2
2
Cp V(dca) (2) were prepared from appropriate metallo-
2
2
cene dichlorides (Cp TiCl and Cp VCl , respectively)
2
2
2
2
by a reaction with sodium dicyanamide in aqueous solu-
tion. Both complexes were characterized by elemental
analysis, vibrational spectra and mass spectrometry.
1
13
Although many transition metal complexes with dicy-
anamide ligand (dca thorough this paper) were studied,
no crystal structure of complex with metals of group IV
or V is known [12]. The aim of this study is to prepare
new pseudohalide metallocene complexes and to deter-
The H and C NMR spectra for diamagnetic titano-
cene compound 1 and fluid solution EPR spectrum for
paramagnetic vanadocene complex 2 were measured.
The structures of both compounds were determined by
single crystal X-ray diffraction analysis.
Both Raman and infrared spectra of 1 and 2 show
absorption bands typical for bent Cp M fragment. IR
2
ꢁ
5
1
*
bands with medium to strong intensity at ꢀ3100 cm
Corresponding author. Tel: +420 46603 7164; fax: +420 46603
correspond to the stretching C–H vibrations of g -
7068.
E-mail address: jaromir.vinklarek@upce.cz (J. Vinkl a´ rek).
ꢁ
1
bonded Cp ring, strong Raman band at ꢀ1130 cm
0
020-1693/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2004.09.030

J. Honz ı´ cˇ ek et al. / Inorganica Chimica Acta 358 (2005) 814–819
815
can be assigned to ‘‘ring breathing’’ mode and the
Table 1
Isotropic hyperfine coupling constant (10 cm ) and g-tensor for N-
ꢁ4
ꢁ1
ꢁ
1
strongest Raman band in the region 270–285 cm is
bending dCp–M–Cp (‘‘ring tilting’’ mode). The presence
of both ‘‘ring breathing’’ and ‘‘ring tilting’’ bands in Ra-
man spectra of prepared complexes unambiguously ver-
2 2
bonded pseudohalide complexes (Cp VX )
a
X
|Aiso
|
g
iso
Ref.
dca
70.2
66.7
70.5
67.9
68.4
1.984
1.985
1.985
1.991
1.990
this work
NNN
NCO
NCS
NCSe
a
[3]
[3]
[3]
[3]
ꢁ4
ifies that in the bent Cp M the moiety remains stable
2
[
13]. The infrared spectrum of 1 contains very strong
ꢁ1
absorption band at 736 cm , which is characteristic
for titanium(IV) compounds with Cp Ti–O–TiCp unit
2
2
Data from [3] were converted from the units of G to the 10
[
was characterized as solvate with dichloromethane, the
14]. Additionally in Raman and IR spectra of 1, which
ꢁ1
e e
cm through division by the factor 1.0698 (g /g), where g = 2.0023.
ꢁ
1
weak band at 2985 cm corresponding to mCH vibration
5
1
of CH Cl was found. In the infrared spectra of both
to the interaction of the unpaired electron with
(I = 7/2; 99.8%) nucleus. Both isotropic hyperfine cou-
V
2
2
compounds studied, three very intensive bands (one
symmetric and two asymmetric C„N stretching vibra-
tions of dca ligand) at 2295 ± 4 , 2244 ± 12 and
ꢁ
4
ꢁ1
pling constant (|Aiso| = 70.2 · 10 cm ) and isotropic
g-factor (giso = 1.984) are in the range characteristic
for other N-bonded pseudohalide vanadocene com-
plexes (see Table 1) [3].
ꢁ
1
2
190 ± 20 cm were observed. In Raman spectra, only
band of the symmetric C„N stretching vibration (2230
cm for 1 and 2236 cm for 2) was found.
ꢁ
1
ꢁ1
Fig. 1 depicts the molecular structure of the com-
plexes 1, important bond lengths and angles are summa-
rized in Table 2. The compound 1 is dinuclear complex
with two titanocene units connected via oxygen bridge
1
The H NMR spectrum of compound 1 shows two
singlet signals at 6.27 ppm (Cp protons) and 5.32 ppm
1
3
(
CH Cl ) in an integral ratio of 10:1. C NMR spec-
2 2
trum of 1 contains single resonance of Cp ring carbons
at 116.8 ppm and low intensity signal of dca ligand car-
bons at 134.2 ppm. The presence of one resonance for
both carbons of dca group suggests fluxionality of dicy-
anamide ligand in solution during NMR experiment.
Singlet signal at 53.4 ppm was assigned to carbon reso-
nance of dichloromethane, which is present in crystal
lattice (see Fig. 1).
and the whole molecule has approximately C symme-
2
try. Similar to the other oxo-bridged dinuclear com-
plexes, the Ti–O–Ti moiety is nearly linear (Ti–O–Ti
angle is 172.9ꢁ). The coordination at each titanium cen-
ter approaches the tetrahedral geometry (Cp–Ti–
Cp = 131.2ꢁ, 131.3ꢁ, N–Ti–O = 93.5ꢁ, 94.6ꢁ). The com-
parison of structural parameters with the other titano-
cene dinuclear complexes shows that the structural
The EPR spectrum of acetone solution of 2 measured
at room temperature shows the expected eight lines due
parameters of (Cp
fected by the pseudohalide ligand exchange (see Table
). Both dca groups act as univalent ligands coordinated
2 2
Ti) O moiety are not significantly af-
4
through the terminal nitrogen atom. The Ti–N bond
˚
lengths (2.10 A) are comparable with dinuclear com-
Cl2
N6
Cl1
˚
plexes [(Cp) Ti(N )] O (2.09 A) [15] or [(CH3-
C5
2
3 2
Table 2
N5
˚
Selected bond distances (A) and angles (ꢁ) for complex 1
C4
Coordination about the titanium atoms
C110
a
1
Ti1–Cg
Ti1–Cg2
2.0671(13)
2.0643(11)
2.0743(11)
2.0668(11)
131.28(5)
131.21(5)
93.48(7)
Ti1–N1
Ti2–N4
2.097(2)
2.097(2)
C3
C19
C23
a
a
a
C16
C24
C24
Ti2–Cg
Ti2–Cg
3
Ti1–O1
Ti2–O1
1.8432(14)
1.8314(14)
172.89(9)
163.34(18)
168.77(19)
C18
Ti1
N4
C22
Ti2
4
C17
a
a
Cg –Ti1–Cg
Cg –Ti2–Cg
1
2
Ti1–O1–Ti2
Ti1–N1–C1
Ti2–N4–C3
O1
3
4
C11
N1–Ti1–O1
N4–Ti2–O1
C21
94.63(7)
C15
C1
C210
C26
Dicyanamide groups
C(1)–N(1)
N(2)–C(1)
C12
C13
N1
C29
1.147(3)
1.291(3)
1.301(3)
1.161(3)
171.9(3)
122.9(2)
173.0(3)
C(3)–N(4)
N(5)–C(3)
1.145(3)
1.298(3)
1.316(4)
1.155(4)
175.3(3)
118.9(2)
174.3(3)
N3
C14
C27
N(2)–C(2)
C(2)–N(3)
N(5)–C(4)
C(4)–N(6)
C28
C2
N2
N(1)–C(1)–N(2)
C(1)–N(2)–C(2)
N(2)–C(2)–N(3)
a
N(4)–C(3)–N(5)
C(3)–N(5)–C(4)
N(5)–C(4)–N(6)
Fig. 1. ORTEP drawing of the molecular structure of [Cp
CH Cl (1) with atom numbering scheme. (ellipsoids: 30%
probability).
2 2
Ti(dca)] O.
2
2
Cg – the centroid of cyclopentadienyl ring.

816
J. Honz ı´ cˇ ek et al. / Inorganica Chimica Acta 358 (2005) 814–819
Table 3
˚
Selected bond distances (A) and angles (ꢁ) for complex 2
N10
Coordination about the vanadium atom
a
V1–Cg
V1–Cg
1
1.9597(9)
1.9633(6)
133.67(4)
85.04(7)
V1–N1
V1–N6
2.0524(17)
2.0515(15)
174.42(18)
175.91(17)
a
C9
C25
2
a
2
Cg –V1–Cg
N1–V1–N6
1
V1–N1–C2
V1–N6–C7
C24
N8
Dicyanamide groups
C(2)–N(1)
N(3)–C(2)
C21
1.154(3)
1.290(3)
1.308(3)
1.146(3)
174.0(2)
121.4(2)
174.3(2)
C(7)–N(6)
N(8)–C(7)
1.152(3)
1.301(3)
1.322(3)
1.153(3)
173.5(2)
119.35(18)
173.2(2)
C7
C23
N6
C22
N(3)–C(4)
C(4)–N(5)
N(8)–C(9)
C(9)–N(10)
V1
N(1)–C(2)–N(3)
C(2)–N(3)–C(4)
N(3)–C(4)–N(5)
a
N(6)–C(7)–N(8)
C(7)–N(8)–C(9)
N(8)–C(9)–N(10)
N1
C2
C14
N3
C4
N5
C13
C15
Cg – the centroid of cyclopentadienyl ring.
C11
C12
˚
C H ) Ti(NCSe)] O (2.09 A) [8] and slightly longer than
5
4 2
2
Fig. 2. ORTEP drawing of the molecular structure of Cp
2
2
V(dca) (2)
those in mononuclear compounds Cp Ti(NCO) [5],
2
2
with atom numbering scheme. (ellipsoids: 30% probability).
Cp Ti(NCS) [6], (t-BuC H ) Ti(NCS) [7], (CH C -
2
2
5
4 2
2
3 5
˚
H ) Ti(NCSe) [8] or Cp Ti(N ) (2.01–2.04 A) [9].
4
2
2
2
3 2
˚
complex 1 (2.10 A) and close to corresponding vanado-
The compound 1 crystallizes with one molecule of
CH Cl , which connects terminal nitrogen atoms of
dicyanamide group by intermolecular hydrogen interac-
˚
cene compounds (CH C H ) V(NCO) (2.03 A) [10] or
3
5
4 2
2
2
2
˚
Cp V(N ) (2.08 A) [11].
2
3 2
The geometrical parameters of dicyanamide moiety
in titanocene compound 1 as well as in vanadocene com-
tions N3ꢂ ꢂ ꢂH5B–C5 and N6ꢂ ꢂ ꢂH5A–C5 (Nꢂ ꢂ ꢂC 3.295(4)
˚
˚
A, Nꢂ ꢂ ꢂH–C 163ꢁ and 3.295 A, 163ꢁ, respectively).
Fig. 2 presents molecular structure of the complex 2;
Table 3 lists the important structural parameters. The
molecule of 2 has typical bent metallocene structure in
˚
˚
pound 2 (C„N = 1.145–1.16 A, N–C = 1.29–1.32 A, N–
C–N = 171.9–175.3ꢁ, C–N–C = 118.9–122.9ꢁ) are com-
parable with the values founded for ionic salt Na(dca)
5
[
20].
which two g -bonded Cp rings and two nitrogen atoms
of dca ligands occupy the pseudotetrahedral coordina-
tion sites around the vanadium(IV) center. V-ring cent-
˚
roid distance (1.96 A) and ring centroid–V–ring centroid
3. Conclusions
angle (133.7ꢁ) are comparable with the other vanado-
cene(IV) complexes [11,16–19]. As well as in 1, the dicy-
anamide ligands are monodentate bonded via the
terminal nitrogen atom and V–N–C bond angles
Sodium dicyanamide reacts with vanadocene and
titanocene dichlorides in aqueous solution forming
new pseudohalide complexes. Two types of complexes
were evidenced by X-ray structure analysis: dinuclear
oxo-bridged titanocene complex 1 and monomeric vana-
docene complex 2. Both complexes were characterized
by spectroscopic measurements and mass spectrometry.
It was shown that in both studied compounds the dicy-
anamide ligand is monodentate bonded via terminal
nitrogen. Formation of these different complexes reflects
diverse reactivity of vanadocene dichloride and titano-
cene dichloride in water solution.
(
gen bond lengths (2.05 A) are slightly shorter than in
174.4ꢁ, 175.9ꢁ) are almost linear. The vanadium–nitro-
˚
Table 4
Comparison of structural parameters for the oxygen-bridged titano-
2 2
cene complexes [Cp TiX] O
a
a
X
Ti–Cg
Ti–O Cg–Ti–Cg
O–Ti-X Ti–O–Ti Ref.
dca
2.068
1.837 131.2
94.1
172.9
this
work
[15]
[8]
N
3
2.088
2.090
2.075
2.084
2.083
2.076
2.068
2.068
1.831 131.4
1.838 131.8
1.836 132.9
1.837 129.6
1.836 131.6
1.835 131.4
1.835 131.8
1.835 132.0
95.5
94.2
94.0
95.9
93.7
88.4
92.7
93.9
172.0
173.4
174.1
173.1
173.3
171.8
174.6
176.1
b
SeCN
CN
Cl
[21]
[22]
[23]
[24]
[25]
[26]
4. Experimental
OOCCF
NO
3
4
.1. Methods and materials
3
c
9 7
C H N
d
All reactions and manipulations were performed un-
3
CH CN
a
b
c
der an inert atmosphere of argon using standard Sch-
lenk techniques. Water was distilled and saturated
with argon. Other solvents were purified by standard
methods, distilled and saturated with argon. Metallo-
Cg – the centroid of the cyclopentadienyl ring.
(CH Ti(NCSe)] O.
(Cp Ti(NCCH CH Ph)) O][FeCl
Ti(NCCH )) O][BPh
[
3
C
5
H
4
)
2
2
[
2
2
2
2
4 2
] .
d
[
(Cp
2
3
2
4 2
] .

J. Honz ı´ cˇ ek et al. / Inorganica Chimica Acta 358 (2005) 814–819
817
cene dichlorides Cp TiCl and Cp VCl were prepared
2
The EPR spectrum was recorded on an ERS 221
(ZWG Berlin) spectrometer at X-band as acetone solu-
tion at ambient temperature.
2
2
2
according to published procedures [27]. Sodium dicyan-
amide was prepared by reaction of Ag(dca) with Na S in
2
aqueous solution, and crude Na(dca) was crystallized
from hot methanol.
Electronic absorption spectra were run on a Hewlett–
ꢁ
2
Packard 8453 spectrometer (solvent CH Cl ; 10 –10
M solutions in 2-cm cuvette).
ꢁ3
2
2
4
.2. Measurements
5
4
.3. Synthesis of [(g -C H ) Ti(dca)] O Æ CH Cl (1)
5
5 2
2
2
2
Positive- and negative-ion electrospray ionization
ESI) mass spectra were measured on an Esquire
000 ion trap analyzer (Bruker Daltonics, Bremen,
Germany) in the range m/z = 50–1000. The samples
were dissolved in acetonitrile (Merck, Darmstadt, Ger-
many) and analyzed by direct infusion at a flow rate of
5
(
3
0.5 g (2.0 mmol) of (g -C H ) TiCl was dissolved in
5 5 2 2
30 ml of boiling water. To this solution, 0.4 g (4.5 mmol)
of sodium dicyanamide was added and the mixture was
rapidly cooled to room temperature. Bright orange pre-
cipitate was filtered, washed with water and vacuum
dried. Crude product was extracted with boiling dichlo-
romethane on a frit and red extract was concentrated in
vacuum. The orange powder precipitated after cooling
dichloromethane solution at dry ice temperature (yield:
0.48 g, 81%). The crystals of 1 suitable for X-ray analy-
sis were obtained by careful layering of CH Cl solution
1
ll/min. The selected precursor ions were further ana-
lyzed by MS/MS analyses under the following condi-
tions: the isolation width m/z = 4, the collision
amplitude 0.8 V, the ion source temperature 300EC,
the flow rate and the pressure of nitrogen 4 l/min
and 10 psi, respectively.
2
2
ꢁ
1
IR spectra were recorded in 4000–350 cm region on
a Perkin–Elmer 684 in KBr pellets. Raman spectra in
with double volume of hexane.
The crystals are stable for several days in air, low
ꢁ1
the region 50–3500 cm were recorded in quartz capil-
laries on a Bruker IFS 55 with FRA 106 extension.
soluble in acetone, CHCl3 and CH CN, and almost
3
insoluble in n-hexane. Heating causes cracking of crys-
tals at about 60 ꢁC (desolvating) and the resulting yel-
low fragments decompose above 180 ꢁC without
1
The H and C NMR spectra were measured at 300
13
K (CDCl solution) on a Bruker Avance 500 and the
3
chemical shifts were referenced to external neat
(
melting.
1
CH ) Si.
3
H NMR (CDCl , ppm): 6.27 (s, 20H); 5.32 (s, 2H).
3
4
Table 5
Crystal data for complexes 1 and 3, measurement and refinement details
a
Compound
1
2
Empirical formula
Molecular weight
Crystal system
Space group
C
24
H
20
N
6
OTi
2
.CH
2
Cl
2
14 10 6
C H N V
589.19
monoclinic
P2 /n (No. 14)
313.22
monoclinic
P2 /n (No. 14)
1
1
˚
a (A)
11.0270(3)
14.6820(3)
16.0680(3)
97.1690(14)
4
9.6380(4)
9.6310(4)
14.8460(5)
106.458(3)
4
˚
b (A)
˚
c (A)
b (ꢁ)
Z
˚
3
V (A )
calc (g cm
2581.05(10)
1.516
1321.60(9)
1.574
ꢁ3
D
)
Crystal size (mm)
Crystal shape
0.4 · 0.25 · 0.1
orange plate
0.857
0.25 · 0.125 · 0.075
green prism
0.752
ꢁ1
l (mm
F(000)
h k l Range
)
1200
ꢁ14, 14; ꢁ19, 19; ꢁ20, 20
636
ꢁ12, 12; ꢁ12, 12; ꢁ19, 19
1–27.5
19508
h Range (ꢁ)
Number of reflections measured
Number of independent reflections (Rint
1–27.5
36075
a
)
5910 (0.0520)
4412
325
3025 (0.042)
2436
190
Number of observed reflections [I > 2r(I)]
Number of parameters refined
˚
ꢁ3
Maximum/minimum Dq (e A
Goodness-of-fit (GoF)
)
0.409/ꢁ0.627
1.025
0.040, 0.1023
0.458/ꢁ0.435
0.928
0.036, 0.1226
b
c
R , wR
c
P
P
a
2
o
2
o;mean
2
o
Rint ¼
jF ꢁ F
j= F .
P
b
c
2
o
2
2
1=2
GoF ¼ ½ ðwðF ꢁ F Þ Þ=ðNdiffrs ꢁ NparamsÞꢃ
for all data.
2
c
P
P
PðwðF
P
2
o
2
c
2
2
o
2
1=2
R(F) = iF
o
|ꢁ|F
c
i/ |F
o
| for observed data, wRðF Þ ¼ ½
ꢁ F Þ Þ=ð wðF Þ Þꢃ for all data.

818
J. Honz ı´ cˇ ek et al. / Inorganica Chimica Acta 358 (2005) 814–819
1
3
C NMR (CDCl , ppm): 116.8 (s, Cp); 134.2 (broad
3
(Sir92) [29] and refined by full-matrix least-square based
2
s, dca); 53.4 (s, CH Cl ).
2
on F (SHELXL-97) [30].
2
+
Positive-ion MS m/z: 543 [M + K] ; 527 [M + Na]
+
Crystal data are summarized in Table 5. Hydrogen
atoms were treated in both structures similarly; they
were calculated into ideal positions, riding during refine-
ment on the respective pivot atom. The isotropic dis-
placement parameters of hydrogen atoms were set to
1.2 Ueq of the attached atom.
Crystallographic data for structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 235476 and 235477 for 1
and 2, respectively. Copies of this information may be
obtained free of charge from The Director, CCDC, 12
Union Road, Cambridge CB2 1EY, UK (fax: +44
1223 336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
+
+
(
100%); 505 [M + H] ; 438 [M ꢁ dca] .
+
MS/MS of 527 m/z 462 [M + Na–Cp] (100%); 438
+
+
[M ꢁ dca] ; 397 [M + Na–2Cp] ; 267 [Cp Ti(dca) + -
Na] ; 178 [Cp Ti] .
2
+
+
2
ꢁ
Negative-ion MS m/z (%): 570 [M + dca] ; 505
ꢁ
ꢁ
[
M + dca-Cp] ; 261 (100%) [Cp Ti(dca)O] .
2
ꢁ
1
IR (KBr-pellet, cm ): 3112(m), 2984(w), 2291(vs),
231(vs), 2171(vs), 1378(s), 1262(m), 1015(s), 820(s),
36(vs), 597(m), 415(m).
Raman (quartz capillary, cm ): 3123(m), 3114(m),
985(w), 2230(vs), 1365(m), 1133(vs), 420(m), 387(m),
73(vs), 129(m).
2
7
ꢁ
1
2
2
UV–Vis (CH Cl , nm): maxima at 334 and 417.
2
2
5
4
.4. Synthesis of (g -C H ) V(dca) (2)
5
5 2
2
Acknowledgements
5
0
0 ml of water and 0.4 g of sodium dicyanamide (4.5
.5 g (2.0 mmol) of (g -C H ) VCl was dissolved in
5
5 2
2
This work was supported by grants from the Ministry
of Education of the Czech Republic (No. CZ
3
mmol) was added to this solution. The resulting mixture
was stirred for 20 min when the dark green precipitate
appeared. Crystals of prepared complex were filtered,
washed with water and vacuum dried (yield: 0.54 g,
2
(
53100001) and Grant Agency of the Czech Republic
No. 203/02/0436). Michal Hol cˇ apek (mass spectrome-
try) acknowledges the support of the Grant Project
No. 203/03/1071 sponsored by the Grant Agency of
the Czech Republic.
8
6%). Single crystals of 2 suitable for X-ray diffraction
were obtained after cooling of saturated acetone solu-
tion to ꢁ15 ꢁC.
The green crystals are stable for several days in air,
soluble in acetone and CH CN, low soluble in CH Cl
or CHCl and practically insoluble in methanol and n-
3
2
2
Appendix A. Supplementary material
3
hexane. EPR (acetone solution): |A | = 75.78 G,
iso
Supplementary data associated with this article can
be found, in the online version at doi:10.1016/
j.ica.2004.09.030.
giso = 1.9844.
Positive-ion MS m/z: 649 [2M + Na] ; 352 [M + K] ;
+
+
+
+
3
36 [M + Na] (100%); 247 [M ꢁ (NCNCN)] . MS/MS
+
+
of 336: m/z 271 [M + Na–Cp] (100%); 247 [M ꢁ dca] .
ꢁ
Negative-ion MS m/z: 691 [2M-H + dca] ; 379
M + dca] (100%); 314 [M + dca-Cp] .
References
ꢁ ꢁ
[
ꢁ1
IR (KBr-pellet, cm ): 3105(s), 3083(m), 2299(vs),
256(vs), 2210(vs), 1413(s), 1320(m), 1092(s), 1071m,
22(s), 903(vs), 721(m), 564(m).
Raman (quartz capillary, cm ): 3113(m), 2236(vs),
131(vs), 662(m), 423(m), 303(m), 286(vs), 142(m).
UV–Vis (CH Cl , nm): maximum at 694 (d–d
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