Reactivity of molybdenum complexes containing mixed NHNPhR and NNPhR hydrazido ligands (R=Ph, Me) toward di-imines. X-ray crystal structures of [MoO(NNPh2)Cl2(bpy)]·CH2Cl2, [MoO(NNPh2)Cl2(phen)]·CH2Cl2 and [Mo(NNPh2)2Cl2(phen)]

Article abstract of DOI:10.1016/S0020-1693(96)05341-8

Complexes of the type [Mo(NHNPhR)(NNPhR)(acac)Cl₂] (R=Ph (I); Me (II)) react in dichloromethane with the di-imines 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) to yield, after slow evaporation under air of the solvent, the species [MoO(NNPhR)Cl₂(bpy)] (R=Ph (III); Me (IV)) and [MoO(NNPhR)Cl₂(phen)] (R=Ph (V); Me (VI)). When these reactions are carried out in toluene under inert atmosphere, I and II give the bis-hydrazido(2-) complexes [Mo(NNPhR)₂Cl₂(bpy)] (R=Ph (VII); Me (VIII)) and [Mo(NNPhR)₂Cl₂(phen)] (R=Ph (IX); Me (X)). The crystal structures of III, V and IX are reported. Crystals of III are orthorhombic, space group Pbca, with cell parameters a=15.290(6), b=16.225(8), c=19.954(9) A, Z=8, R=0.036 and R_w=0.044. Crystals of V are triclinic, space group P1, with a=8.935(1), b=12.960(2), c=13.443(2) A, α=61.84(1), β=74.75(1), γ=86.96(1)°, Z=2, R=0.036 and R_w=0.044. Crystals of IX are triclinic, space group P1, with a=9.812(4), b=10.459(4), c=17.979(7) A, α=73.69(3), β=77.98(3), γ=66.30(3)°, Z=2, R=0.038 and R_w=0.043. All complexes display similar pseudooctahedral geometries with the hydrazido(2-) ligands adopting the nearly linear coordination mode.

Full text of DOI:10.1016/S0020-1693(96)05341-8

Inorganica Chimica Acta 255 (1997) 73–80
Reactivity of molybdenum complexes containing mixed NHNPhR and
NNPhR hydrazido ligands (RsPh, Me) toward di-imines. X-ray crystal
structures of [MoO(NNPh2)Cl2(bpy)]PCH2Cl2,
[MoO(NNPh2)Cl2(phen)]PCH2Cl2 and [Mo(NNPh2)2Cl2(phen)]
U
U
U
Carolina Manzur a, Carlos Bustos a,1, David Carrillo a, , Daphne Boys b, , Jean-Rene´ Hamon c,
a Laboratorio de Qu´ımica Inorga´nica, Instituto de Qu´ımica, Universidad Cato´lica de Valpara´ıso, Avda. Brasil 2950, Valpara´ıso, Chile
b Departamento de F´ısica, Facultad de Ciencias F´ısicas y Matema´ticas, Universidad de Chile, Casilla 487-3, Santiago, Chile
c Laboratoire de Chimie des Complexes de Me´taux de Transition et Synthe`se Organique, URA CNRS 415, Universite´ de Rennes I, Campus de Beaulieu,
35042 Rennes, France
Received 12 February 1996; revised 12 April 1996
Abstract
Complexes of the type [Mo(NHNPhR)(NNPhR)(acac)Cl2](R sPh (I); Me (II)) react in dichloromethane with the di-imines 2,29-
bipyridine (bpy) and 1,10-phenanthroline (phen) to yield, after slow evaporation under air of the solvent, the species
[MoO(NNPhR)Cl2(bpy)] (RsPh (III); Me (IV)) and [MoO(NNPhR)Cl2(phen)] (RsPh (V); Me (VI)). When these reactions are
carried out in toluene under inert atmosphere, I and II give the bis-hydrazido(2y) complexes [Mo(NNPhR)2Cl2(bpy)] (RsPh (VII);
Me (VIII)) and [Mo(NNPhR)2Cl2(phen)] (RsPh (IX); Me (X)). The crystal structures of III, V and IX are reported. Crystals of III
˚
are orthorhombic, space group Pbca, with cell parameters as15.290(6), bs16.225(8), cs19.954(9) A, Zs8, Rs0.036 and Rws0.044.
#
˚
Crystals of V are triclinic, space group P1, with as8.935(1), bs12.960(2), cs13.443(2) A, as61.84(1), bs74.75(1), gs86.96(1)8,
#
˚
Zs2, Rs0.036 andRws0.044. Crystals ofIXaretriclinic, spacegroupP1, with as9.812(4), bs10.459(4), cs17.979(7)A,as73.69(3),
bs77.98(3), gs66.30(3)8, Zs2, Rs0.038 and Rws0.043. All complexes display similar pseudooctahedral geometries with the hydra-
zido(2y) ligands adopting the nearly linear coordination mode.
Keywords: Molybdenum complexes; Hydrazido complexes; Bidentate nitrogen ligand complexes; Crystal structures
1. Introduction
lability of the ancillary ligand acac and its ability to depro-
tonate the NHNPhR ligand, thus regenerating the acetylace-
tone (Hacac) molecule.
There arefewexamplesintheliteratureofmetalcomplexes
containing both organohydrazido(1y) and organohydra-
zido(2y) ligands adopting the ‘end-on’ configuration in the
same inner coordination sphere [1–3]. Recently, we have
reported the synthesis and characterization of complexes for-
mulated as [Mo(NHNPhR)(NNPhR)(acac)X2](R sMe,
Ph; XsCl, Br, I), where the organodinitrogen ligands pos-
sess such a similar conformation [4]. These compoundshave
proved to be versatile precursors for the synthesis of a wide
variety of phosphine complexes containing the cis-
Mo(NNPhR)2 moiety [5]. Certainly, the interesting chem-
ical properties observed for these compounds are due to the
As a new contribution to the study of the chemical prop-
erties of hydrazido complexes [6] we report, in this article,
the reactivity of the molybdenum complexes [Mo(NHN-
PhR)(NNPhR)(acac)Cl2](R sPh (I); Me (II)) toward
di-imines in dichloromethane and toluene. The new coordi-
nation compounds obtained from these reactions were
characterized by elemental analyses, spectroscopic methods
and were formulated as [MoO(NNPhR)Cl2(bpy)] (RsPh
(III); Me (IV)), [MoO(NNPhR)Cl2(phen)] (RsPh
(V); Me (VI)), [Mo(NNPhR)2Cl2(bpy)] (RsPh (VII);
Me (VIII)) and [Mo(NNPhR)2Cl2(phen)] (RsPh (IX);
Me (X)). The X-ray crystal structures of complexes III, V
and IX have been determined in order to correlate the trans
influence of the oxo and hydrazido(2y) ligands on the nitro-
U Corresponding authors.
1 Present address: Instituto de Qu´ımica, Facultad de Ciencias, Universi-
dad Austral de Chile, Casilla 567, Valdivia, Chile.
0020-1693/97/$17.00 q 1997 Elsevier Science S.A. All rights reserved
PII S0020-1693(96)05341-8

74
C. Manzur et al. / Inorganica Chimica Acta 255 (1997) 73–80
gen atoms of the di-imines ligands. Finally, the electrochem-
ical behavior of complexes V and IX was also explored.
(4.73), 298sh (4.35), 338br (3.88), 382br (3.83), 506br
(3.18). IR (cmy1, KBr): 3048(w), n(CH); 1587(m),
n(NN); 1488(m), n(CC); 901(s), n(Mo_O). H NMR
1
(CDCl3, d (ppm), TMS): 5.31 (s, 2H, CH2Cl2); 7.36–10.15
2. Experimental
(m, 18H, phenyl and phen).
2.1. Chemicals
2.2.1.4. [MoO(NNPhMe)Cl2(phen)] (VI)
Yield 55%. M.p. 295 8C. Anal. Calc. for C19H16Cl2Mo-
N4O: C 47.2; H, 3.34. Found: C, 46.8; H, 3.52%. UV–Vis
((CH2Cl2), lmax (nm) (log e)): 276 (4.58), 298sh (4.18),
342 (3.76), 384br (3.66), 514br (2.94). IR (cmy1, KBr):
3055(w), n(CH); 2930(w), n(CH); 1586(m), n(NN);
1473(s), n(CC); 903(s), n(Mo_O). 1H NMR (DMSO-d6,
d (ppm), TMS): 3.64, 4.15, 4.50 (s, 3H, CH3N); 6.85–10.00
(m, 13H, phenyl and phen).
2,29-Bipyridine and 1,10-phenanthroline were obtained
from commercial sources and used without further purifica-
tion. Complexes I and II were synthesized as previously
described [4]. Dichloromethane and toluene were distilled
from P4O10 and sodium benzophenone ketyl, respectively.
All synthetic manipulations were carried out utilizing stan-
dard Schlenk techniques unless specified. Dinitrogen was
used as inert atmosphere.
2.2. Preparation of complexes
2.2.2. Bis-hydrazido(2y) complexes. General procedure
To a suspension of 1.00 mmol of complexes I or II (0.520
or 0.640 g, respectively) in dry toluene (20 ml) was added
1.00 mmol of bpy or phen (0.160 and 0.180 g, respectively).
The reaction mixture was refluxed for 15 min, under dinitro-
gen. Under these experimental conditions deep purple (VII
and IX), deep orange (VIII) and brick red (X) microcrys-
talline solids began to form. The solids were filtered off,
washed with toluene and hexane, and dried in vacuo.
2.2.1. Oxo-hydrazido(2y) complexes. General procedure
To a solution of 0.50 mmol of complexes I or II (0.260
and 0.320 g, respectively) in dry dichloromethane (50 ml)
was added 0.50 mmol of bpy or phen (0.078 and 0.090 g,
respectively). The reaction mixture was refluxed for 0.5 h
and allowed to evaporate slowly under air for one or two
weeks yielding deep purple (III–V) and brick red (VI)
crystalline solids. These materials were filtered off, washed
with three portions of 10 ml of CH2Cl2 , and dried in vacuo.
Complexes III–VI are sparingly soluble in CH2Cl2. Suitable
crystals for an X-ray structure determination were directly
obtained for complexes III and V.
2.2.2.1. [Mo(NNPh2)2Cl2(bpy)] (VII)
Yield 93%. M.p. 257 8C, dec. Anal. Calc. for
C34H28Cl2MoN6: C, 59.4; H, 4.11. Found: C, 59.0; H, 4.32%.
UV–Vis ((CH2Cl2), lmax (nm) (log e)): 246sh (3.07), 302
(4.60), 315sh (3.34), 356sh (4.03), 470br (3.74). IR
(cmy1, KBr): 3056(w), n(CH); 2922(w), n(CH);
2.2.1.1. [MoO(NNPh2)Cl2(bpy)]PCH2Cl2 (III)
Yield 50%. M.p. 235 8C, dec. Anal. Calc. for
C23H20Cl4MoN4O: C, 45.6; H, 3.33. Found: C, 45.8; H,
3.42%. UV–Vis ((CH2Cl2), lmax (nm) (log e)): 268
(4.36), 304 (4.23), 348 (3.80), 382 (3.74), 504br (3.12).
IR (cmy1, KBr): 3049(w), n(CH); 1600(m), n(NN);
1490(m), n(CC); 905(s), n(Mo_O). 1H NMR (CDCl3, d
(ppm), TMS): 5.31 (s, 2H, CH2Cl2); 7.02–9.92 (m, 18H,
phenyl and bpy).
1
1591(s), n(NN); 1486(s), n(CC). H NMR (CDCl3, d
(ppm), TMS): 6.91–8.78 (m, phenyl and bpy).
2.2.2.2. [Mo(NNPhMe)2Cl2(bpy)] (VIII)
Yield 80%. M.p. 205 8C, dec. Anal. Calc. for
C24H24Cl2MoN6: C, 51.2; H, 4.29; N, 14.9. Found: C, 51.0;
H, 4.32; N, 15.0%. UV–Vis ((CH2Cl2), lmax (nm) (log e)):
248sh (4.39), 300 (4.58), 312sh (4.50), 348sh (4.11),
480br (3.45). IR (cmy1, KBr): 3056(w), n(CH);
2.2.1.2. [MoO(NNPhMe)Cl2(bpy)] (IV)
Yield 69%. M.p. 233 8C, dec. Anal. Calc. for
C17H16Cl2MoN4O: C, 44.5; H, 3.51. Found: C, 44.6; H,
3.64%. UV–Vis ((CH2Cl2), lmax (nm) (log e)): 268
(4.38), 304 (4.24), 350 (3.85), 390sh (3.73), 504br (3.10).
IR (cmy1, KBr): 3076(w), n(CH); 2922(w), n(CH);
1599(m), n(NN); 1473(s), n(CC); 905(s), n(Mo_O).
1H NMR (DMSO-d6, d (ppm), TMS): 3.65, 4.16, 4.34 (s,
3H, CH3N); 7.23–9.61 (m, 13H, phenyl and bpy).
1
2922(w), n(CH); 1592(s), n(NN); 1489(s), n(CC). H
NMR (CDCl3, d (ppm), TMS): 3.64, 4.11, 4.25 (s, 6H,
CH3N); 6.86–9.94 (m, 18H, phenyl and bpy).
2.2.2.3. [Mo(NNPh2)2Cl2(phen)] (IX)
Yield 83%. M.p. 260 8C, dec. Anal. Calc. for
C36H28Cl2MoN6: C, 60.8; H, 3.97. Found: C, 59.6; H, 4.14%.
UV–Vis ((CH2Cl2), lmax (nm) (log e)): 276 (4.72), 286sh
(4.57), 360sh (4.02), 460br (3.73). IR (cmy1, KBr):
2.2.1.3. [MoO(NNPh2)Cl2(phen]PCH2Cl2 (V)
1
Yield 85%. M.p. 275 8C, dec. Anal. Calc. for
C25H20Cl4MoN4O: C, 47.6; H, 3.20. Found: C, 47.7; H,
3.19%. UV–Vis ((CH2Cl2), lmax (nm) (log e)): 276
3056(w), n(CH); 1589(s), n(NN); 1489(s), n(CC). H
NMR (CDCl3, d (ppm), TMS): 6.94–9.02 (m, phenyl and
phen).

C. Manzur et al. / Inorganica Chimica Acta 255 (1997) 73–80
75
2.2.2.4. [Mo(NNPhMe)2Cl2(phen)] (X)
omel electrode (SCE) as the reference. All measurements
were made at room temperature (20 8C) in CH2Cl2 with 0.1
M tetrabutylammonium hexafluorophosphate, Bu4NPF6,as
the supporting electrolyte.
Yield 75%. M.p. 220 8C, dec. Anal. Calc. for
C26H24Cl2MoN6: C, 53.2; H, 4.12; N, 14.3. Found: C, 53.1;
H, 4.11; N, 14.4%. UV–Vis ((CH2Cl2), lmax (nm) (log e)):
276 (4.50), 296sh (4.41), 346sh (4.06), 480br (3.39). IR
(cmy1, KBr): 3052(w), n(CH); 2921(w), n(CH);
2.4. X-ray data collection and crystal structure
determination of complexes III, V and IX
1
1583(s), n(NN); 1485(s), n(CC). H NMR (CDCl3, d
(ppm), TMS): 3.55, 4.17, 4.31 (s, 6H, CH3N); 6.80–10.18
(m, 18H, phenyl and phen).
X-ray diffraction data were collected on a Siemens R3m/
V four-circle diffractometer, using graphite-monochromated
Mo Ka radiation (ls0.71073 A), in u/2u scan mode at
˚
2.3. Physical measurements
room temperature. Cell parameters were determined from
least-squares fits of 25 reflections with 10F2uF308. Two
standard reflections, monitored every 98 reflections, showed
no significant intensity variation during data collection from
the samples. Intensities were corrected for Lorentz and polar-
ization effects, and semi-empirical corrections were applied
for absorption.
Crystal data, data collection and refinement parametersfor
compounds III, V and IX are summarized in Table 1. The
three structures were solved by direct methods and refined
on F by full-matrix least-squares calculations. The function
1H NMR spectra were recorded in CDCl3 and DMSO-d6
on a Bruker FT AC/200 P spectrometer at 22 8C. IR spectra
were obtained as KBr disks with a Perkin-Elmer model 1600
FT-IR spectrophotometer. Electronic spectra were recorded
in CH2Cl2 solutions on a Hewlett Packardmodel8452Aspec-
trophotometer. Melting points were determined using a
Kofler apparatus and were not corrected. Cyclic voltammetry
(CV) measurements were made with a homemade poten-
tiostat of conventional designusingathree-electrodecellwith
platinum working and auxiliary electrodes and saturated cal-
Table 1
Crystallographic data for compounds III, V and IX
III
V
IX
36H28Cl2MoN6
Empirical formula
Crystal size (mm)
Crystal system
C23H20Cl4MoN4OC
25H20Cl4MoN4OC
0.40=0.36=0.20
orthorhombic
Pbca
0.32=0.22=0.20
0.40=0.40=0.l2
triclinic
triclinic
#
#
Space group
P 1
P 1
Unit cell dimensions
˚
a (A)
15.290(6)
16.225(8)
19.954(9)
90.0
90.0
90.0
8.935(1)
12.960(2)
13.443(2)
61.84(1)
74.75(1)
86.96(1)
1319.5(4)
9.812(4)
10.459(4)
17.979(7)
73.69(3)
77.98(3)
66.30(3)
1612(1)
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
Volume (A )
Z
3
˚
4950(4)
822
Molecular weight
Density (calc.) (Mg my3
F(000)
606.2
1.627
2432
0.986
0.202/0.111
4561
630.2
1.586
632
0.928
0.990/0.823
7834
711.5
1.466
724
0.609
0.825/0.650
6225
)
Absorption coefficient (mmy1
)
Max./min. transmission factors
Reflections collected
2u Range (8)
3–50
3–55
3–50
Index ranges
h
k
l
0to18
0to11
y5to11
y7to19
y8to23
4375
y16 to 16
y16 to 17
6084
y11 to 12
y20 to 21
5721
Independent reflections
Rint
0.0134
3026 (F)4s(F))
0.0007
298
0.0120
5120 (F)6s(F))
0.0020
0.0119
4794(F)4s(F))
0.0022
Observed reflections
Weighting scheme g (wy1ss2(F)qgF2)
No. parameters refined
316
406
Final R indices
R
Rw
0.036
0.044
1.11
0.036
0.044
1.18
0.038
0.043
1.02
Goodness-of-fit, S
Residual rmax (e A
y3
˚
)
0.60
1.36
0.73

76
C. Manzur et al. / Inorganica Chimica Acta 255 (1997) 73–80
minimized was 8w(FoyFc)2. The weighting scheme used
was given by wy1ss2(F)qgF2. All non-H atoms were
refined anisotropically. A riding model was applied to H
On the other hand, in dry toluene, the di-imines bpy and
phen react with complexes I and II to produce cleanly
bis-hydrazido(2y) complexes formulated as [Mo-
(NNPhR)2Cl2(bpy)] (RsPh (VII); Me (VIII)) and
[Mo(NNPhR)2Cl2(phen)] (RsPh (IX); Me (X)). These
complexes are sparingly soluble in toluene and rapidly pre-
cipitate as microcrystalline materials. Presumably, this prop-
erty prevents or minimizes the hydrolysis of one PhRNN
ligand of the Mo(NNPhR)2 moiety present in complexes
VII–X.
˚
atoms, placed at calculated positionswithC–Hs0.96A,with
the equivalent isotropic thermal parameters of their parent C
atoms. All calculations were performed with the Siemens
SHELXTL-PLUS system of programs [7].
3. Results and discussion
The formulations attributed to both types of complexes,
III–VI and VII–X, are consistent with analytical and spec-
troscopic data and with the X-ray crystallographic studies of
III, V and IX (vide infra).
3.1. Reactivity and synthesis of complexes
We have previously reported [5] that in acetonitrile terti-
ary phosphines react with molybdenum complexes contain-
ing both hydrazido(1y) and hydrazido(2y) ligands,
[Mo(NHNPhR)(NNPhR)(acac)Cl2]R( sPh (I); Me
(II)), to give, after elimination of one acetylacetone mole-
cule, five- and six-coordinated molybdenum complexes
depending on the steric hindrance of the phosphines. These
complexes exhibit, in all cases, the robust cis-Mo(NNPhR)2
core and one or two ancillary phosphine ligands. The chloro
ligands are retained in the inner coordination sphere of
molybdenum.
3.2. X-ray structures of complexes III, V and IX
Atomic coordinates for the structures of [MoO(NNPh2)-
Cl2(bpy)]PCH2Cl2 (III), [MoO(NNPh2)Cl2(phen)]P
CH2Cl2 (V) and [Mo(NNPh2)2Cl2(phen)] (IX) are given
in Tables 2, 3 and 4, respectively, and relevantbonddistances
Table 2
Fractional atomic coordinates (=104) and equivalent isotropic displace-
2
3
˚
ment coefficients (A =10 ) for complex III
This type of reaction wasnowrepeatedusingbpyandphen,
both in dichloromethane and toluene. In dichloromethane the
di-imines react with complexes I and II to afford clean solu-
tions which were allowed to stand in air. The slow evapora-
tion of thesolventyieldscrystallinesolidswhichwerewashed
with abundant quantities of CH2Cl2. These new compounds
were characterized by conventional spectroscopictechniques
and formulated as [MoO(NNPhR)Cl2(bpy)] (RsPh
(III); Me (IV)) and [MoO(NNPhR)Cl2(phen)] (RsPh
(V); Me (VI)). The presence of the cis-MoO(NNPhR)
moiety in complexes III–VI indicates unambiguously that
the Mo(NNPhR)2 group, initially present in the species
formed in solution (Eq. (1)), undergoes a partial hydrolysis
with loss of one PhRNN ligand (Eq. (2)) during the slow
evaporation of the solvent under air. In fact, complex V
was obtained contaminated with crystals of complex
[Mo(NNPh2)2Cl2(phen)] (IX) and it was possible to sep-
arate by hand suitable crystals of both complexes for X-ray
structure determinations.
a
x
y
z
Ueq
Mo
331(1)
1458(1)
y421(1)
y61(2)
1244(2)
1337(2)
y418(2)
8694(1)
7651(1)
9951(1)
8616(2)
9125(2)
9615(2)
8102(2)
7745(2)
8835(3)
9137(3)
9734(3)
3784(1)
3861(1)
3460(1)
4580(1)
2925(2)
4183(2)
3288(2)
2954(2)
2296(2)
1772(2)
1902(3)
2544(3)
3054(2)
3757(2)
3977(3)
4640(3)
5072(3)
4824(2)
3294(2)
3993(2)
4323(3)
3966(3)
3280(3)
2932(3)
2235(2)
1899(2)
1213(3)
867(3)
34(1)
53(1)
46(1)
44(1)
35(1)
34(1)
37(1)
38(1)
44(2)
52(2)
57(2)
50(2)
38(1)
37(1)
48(2)
53(2)
49(2)
42(2)
38(1)
50(2)
60(2)
62(2)
57(2)
47(2)
37(1)
46(2)
54(2)
63(2)
71(2)
56(2)
86(1)
101(1)
106(3)
Cl(l)
Cl(2)
O
N(1)
N(2)
N(3)
N(4)
C(l)
y1039(2)
1173(3)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
Cl(3)
Cl(4)
C(Ol)
1671(3)
2275(3)
2370(3)
1849(3)
1904(3)
2480(3)
2461(3)
1881(3)
10031(3)
9710(3)
9987(3)
10587(3)
10831(3)
10460(3)
9863(3)
7453(3)
7486(3)
7210(3)
6907(3)
6894(3)
7158(3)
7732(3)
7004(3)
7010(3)
7730(4)
8457(4)
8454(3)
9371(1)
9497(1)
9044(5)
1332(3)
y1809(3)
y1847(3)
y2578(4)
y3284(4)
y3260(3)
y2520(3)
y978(3)
y802(3)
y713(3)
y787(4)
y964(4)
y1059(4)
171(1)
[Mo(NHNPhR)(NNPhR)(acac)Cl2]qN-N
™[Mo(NNPhR)22Cl (N-N)]qHacac (1)
[Mo(NNPhR)22Cl (N-N)]qHO
2
™[MoO(NNPhR)Cl22(N-N)]qPhRNNH
N-Nsbpy, phen
(2)
1195(3)
1884(3)
y1730(1)
y509(1)
y876(4)
A comparable observation was recently reported for the
ionic complex [Re(NNPhMe)2Cl2(PPh3)][PF6] which
afforded, after recrystallization from a CH2Cl2/MeOH mix-
ture, the unexpected oxo-hydrazido complex, [ReO(NNPh-
Me)Cl(PPh3)2][PF6]2 [8].
y910(1)
y33(5)
a EquivalentisotropicUdefinedasone thirdofthetraceoftheorthogonalized
Uij tensor.

C. Manzur et al. / Inorganica Chimica Acta 255 (1997) 73–80
77
Table 3
Table 4
Fractional atomic coordinates (=104) and equivalent isotropic displace-
Fractional atomic coordinates (=104) and equivalent isotropic displace-
2
3
2
3
˚
˚
ment coefficients (A =10 ) for complex V
ment coefficients (A =10 ) for complex IX
a
a
x
y
z
Ueq
x
y
z
Ueq
Mo
y3108(1)
y4049(1)
y1380(1)
y4688(3)
y732(3)
y2297(3)
y3349(3)
y3580(3)
5(4)
1411(4)
2089(4)
1355(3)
1983(4)
3141(1)
1193(1)
4850(1)
3851(2)
2336(2)
3512(2)
2785(2)
2654(2)
1719(3)
1223(3)
1416(3)
2081(3)
2336(3)
2965(3)
3373(3)
4002(3)
4367(3)
4102(3)
3146(2)
2506(2)
3081(3)
3763(3)
4172(4)
3896(4)
3228(5)
2810(4)
2093(3)
909(3)
3829(1)
5442(1)
2341(1)
4082(2)
4046(2)
5115(2)
2742(2)
1910(2)
3532(3)
3732(4)
4429(3)
4976(3)
5710(3)
6235(3)
6065(3)
6595(3)
6374(3)
5639(3)
5325(2)
4763(2)
1483(3)
1876(3)
1466(4)
715(4)
35(1)
50(1)
53(1)
46(1)
39(1)
36(1)
41(1)
43(1)
52(2)
59(2)
54(2)
43(1)
51(1)
52(2)
41(1)
51(2)
53(2)
45(1)
35(1)
36(1)
43(1)
55(2)
67(2)
77(3)
88(3)
71(3)
40(1)
66(2)
76(2)
61(2)
60(2)
55(2)
141(1)
196(2)
144(5)
Mo
75(1)
1011(1)
y144(1)
1721(3)
2450(3)
y1383(3)
y2524(3)
y708(3)
y1513(3)
1337(5)
2377(6)
3845(6)
4310(4)
5833(5)
6202(5)
5092(4)
5411(5)
4277(6)
396(1)
2267(1)
2701(1)
1901(1)
3592(1)
3568(2)
2257(2)
3174(2)
3417(2)
1963(2)
1466(2)
4235(2)
4755(3)
4567(3)
3868(3)
3601(3)
2928(4)
2436(3)
1712(3)
1301(3)
1588(2)
2677(2)
3397(2)
3239(2)
3101(2)
2915(2)
2879(2)
3023(2)
3195(2)
3842(2)
4539(2)
4936(3)
4648(3)
3965(3)
3551(2)
1250(2)
1110(2)
922(3)
34(1)
48(1)
52(1)
40(1)
41(1)
39(1)
41(1)
41(1)
44(1)
51(2)
63(2)
63(2)
51(2)
68(2)
71(2)
54(2)
66(2)
67(2)
53(2)
41(1)
41(1)
38(1)
45(2)
53(2)
58(2)
54(2)
44(2)
39(1)
50(2)
62(2)
64(2)
58(2)
48(2)
45(2)
61(2)
84(3)
91(3)
83(3)
58(2)
42(2)
51(2)
71(2)
90(3)
85(3)
62(2)
Cl(l)
Cl(2)
O
Cl(1)
Cl(2)
N(1)
N(2)
N(3)
N(4)
N(5)
N(6)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(61)
C(62)
C(63)
C(64)
C(65)
C(66)
y1791(1)
y20(3)
y992(3)
1680(3)
2722(3)
176(3)
N(1)
N(2)
N(3)
N(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
Cl(3)
Cl(4)
C(Ol)
153(3)
437(4)
131(5)
y636(5)
y1121(4)
y1866(5)
y2264(5)
y2001(4)
y2413(5)
y2113(5)
y1409(4)
y1283(3)
y800(4)
3053(4)
1992(4)
2334(4)
3695(5)
4742(5)
4427(4)
3553(3)
3816(4)
4590(5)
5086(5)
4814(4)
4036(4)
1374(4)
1208(5)
2419(8)
3756(7)
3903(5)
2713(4)
y1119(4)
y2432(4)
y3659(5)
y3581(7)
y2275(7)
y1043(5)
1204(4)
y271(4)
y1144(4)
y2543(5)
y3078(4)
y902(3)
y73(3)
y4910(4)
y5849(5)
y7147(5)
y7543(5)
y6599(6)
y5264(5)
y2409(4)
y2315(6)
y1104(6)
y54(5)
2801(5)
3591(4)
3188(4)
y3999(4)
y4353(4)
y5790(5)
y6838(5)
y6478(5)
y5055(4)
y2230(4)
y3071(4)
y2749(5)
y1611(5)
y757(5)
y1062(4)
y2827(4)
y4076(5)
y5331(5)
y5356(6)
y4136(7)
y2841(5)
y1010(4)
y294(5)
185(6)
308(5)
689(4)
1398(3)
2011(3)
1547(4)
499(4)
y104(3)
342(3)
1807(2)
1267(3)
1766(6)
395(3)
1068(3)
2244(3)
2776(3)
y1978(2)
y1094(2)
y936(7)
y169(5)
y1342(4)
y4091(2)
y6912(3)
y5423(12)
a EquivalentisotropicUdefinedasone thirdofthetraceoftheorthogonalized
Uij tensor.
876(3)
1029(3)
1213(3)
1162(2)
1632(2)
1333(3)
606(4)
and angles are given in Table 5. ORTEP views of each mol-
ecule, in similar perspectives for sake of comparison, are
presented in Fig. 1. The geometry about the molybdenum
center in III, V and IX is best described as distorted octahe-
dral with the chloro ligands occupying mutually trans
positions.
27(7)
y736(7)
y1218(6)
134(3)
410(2)
a EquivalentisotropicUdefinedasone thirdofthetraceoftheorthogonalized
Uij tensor.
The geometric parameters observed in III and V are quite
similar to those described in the literature for other oxo-
hydrazido(2y)molybdenum complexes [9–18]. The short
Mo–N and N–N bond distances of 1.792(4) and 1.296(5)
A for III, and 1.791(4) and 1.276(5) A for V, respectively,
the nearly linear Mo–N–N bond angle of 172.4(3) and
173.1(2)8 for III and V, respectively, and the nearly planar
MoNNC2 unit is indicative of an extensive delocalization of
p-electron density throughout the hydrazidomolybdenum
unit. The well known strong trans influence exerted by the
oxo and hydrazido(2y) ligands [9–18] is also observed on
the nitrogen atoms of bpy and phen in complexes III and V.
Thus, the Mo–N(1) bond distances trans to the oxo ligands,
˚
˚
˚
2.318(4) and 2.342(3) A, respectively, are longer by ;0.12
˚
and ;0.14 A, compared with a normal Mo–N(bpy) distance
[19]. Likewise, the Mo–N(2) bond distances trans to the
˚
NNPh2 ligands, 2.289(4) and 2.286(3) A, respectively, are
˚
also longer by ;0.08 A compared to the same parameter
[19]. Clearly, the trans influence of the oxo ligands is far
more important than that of the hydrazido(2y) ligands. On

78
C. Manzur et al. / Inorganica Chimica Acta 255 (1997) 73–80
Table 5
˚
Selected bond distances (A) and bond angles (8) for complexes III, V and
IX
III
V
IX
Mo–Cl(l)
Mo–Cl(2)
Mo–O
2.421(2)
2.429(2)
1.703(3)
2.318(4)
2.289(4)
1.792(4)
2.425(1)
2.419(1)
1.691(2)
2.342(3)
2.286(3)
1.791(4)
2.461(1)
2.457(1)
Mo–N(l)
2.310(4)
2.309(3)
1.779(3)
1.773(4)
1.309(4)
1.429(5)
1.446(6)
1.319(5)
1.432(4)
1.443(5)
Mo–N(2)
Mo–N(3)
Mo–N(5)
N(3)–N(4)
N(4)–C(31)
N(4)–C(41)
N(5)–N(6)
N(6)–C(51)
N(6)–C(61)
1.296(5)
1.439(6)
1.438(5)
1.276(5)
1.427(5)
1.454(5)
Cl(l)–Mo–Cl(2)
Cl(l)–Mo–O
Cl(2)–Mo–O
160.2(1)
98.0(1)
98.3(1)
80.1(1)
80.5(1)
87.4(1)
82.1(1)
96.7(1)
90.0(1)
161.5(1)
98.3(1)
97.6(1)
80.1(1)
81.5(1)
87.2(1)
84.5(1)
94.0(1)
90.9(1)
164.1(1)
Cl(l)–Mo–N(l)
Cl(2)–Mo–N(l)
Cl(l)–Mo–N(2)
Cl(2)–Mo–N(2)
Cl(l)–Mo–N(3)
Cl(2)–Mo–N(3)
Cl(l)–Mo–N(5)
Cl(2)–Mo–N(5)
O–Mo–N(l)
86.5(1)
80.1(1)
79.4(1)
88.0(1)
90.3(1)
98.7(1)
97.8(1)
92.1(1)
157.5(1)
87.7(1)
104.5(2)
69.8(1)
98.0(1)
166.4(1)
156.6(1)
86.2(1)
104.9(1)
70.5(1)
98.5(1)
168.5(1)
O–Mo–N(2)
O–Mo–N(3)
N(l)–Mo–N(2)
N(l)–Mo–N(3)
N(2)–Mo–N(3)
N(l)–Mo–N(5)
N(2)–Mo–N(5)
N(3)–Mo–N(5)
Mo–N(3)–N(4)
Mo–N(5)–N(6)
N(3)–N(4)–C(31)
N(3)–N(4)–C(41)
C(31)–N(4)–C(41)
N(5)–N(6)–C(51)
N(5)–N(6)–C(61)
C(51)–N(6)–C(61)
70.8(1)
91.9(1)
160.3(2)
160.5(1)
91.3(1)
106.9(1)
171.3(3)
170.1(2)
120.8(4)
117.7(3)
121.5(3)
119.4(3)
117.7(3)
122.9(4)
172.4(3)
173.1(2)
120.2(3)
118.2(3)
121.2(3)
120.9(3)
117.1(3)
122.0(3)
Fig. 1. Views of the molecular structures of (a) [MoO(NNPh2)Cl2(bpy)]
(III), (b) [MoO(NNPh2)Cl2(phen)] (V) and (c) [Mo(NNPh2)Cl2-
(phen)] (IX), with 50% probability ellipsoids (hydrogen atoms omitted
for clarity).
the other hand, the Mo–O bond distances of 1.703(3) and
1.691(2) A for III and V, respectively, lie within the normal
˚
range [9–15,20].
3.3. Spectroscopic studies
In complex IX the diphenylhydrazido(2y) ligands are cis
to one another but trans to the nitrogen atoms of the phen
ligand. The trans influence exerted by these ligands on the
Mo–N(1) and Mo–N(2) bond distances is stronger than that
exerted in complexes III and V, e.g. Mo–N(1)s2.310(4)
The characterization of complexes III–X was carried out
by chemical analysis and by IR, UV–Vis and H NMR
spectroscopic techniques.
The IR spectra of oxo-hydrazido(2y) complexes, III–
VI, display characteristic strong and sharp bands in the 1586–
1600 and 901–905 cmy1 regions, assigned to n(N_N)
[1,11,19,22] and n(Mo_O) [23], respectively. Thesespec-
tra show also weak absorption bands in the 3048–3076 cmy1
region associated with n(C–H) of the aromatic groups and,
additionally, for complexes IV and VI, weak bands in the
1
˚
and Mo–N(2)s2.309(3) A for IX versus Mo–N(1)
˚
s2.289(4) and 2.286(3) A for III and V, respectively. The
metrical parameters for the Mo(NNPh2)2 core (Table 5) are
similar to those reported in the literature [5,19,21] andreveal
extensive electronic delocalization throughout the MoNNC2
units as well.

C. Manzur et al. / Inorganica Chimica Acta 255 (1997) 73–80
79
2922–2930 cmy1 region associated with n(C–H) of the
methyl groups. On the other hand, excepting the absorption
band corresponding to n(Mo_O), the IR spectra of bis-
hydrazido(2y) complexes, VII–X, are very similar to those
exhibited by complexes III–VI.
The electronic spectra of compounds III–X were recorded
in CH2Cl2. Complexes III–VI display comparable spectra
indicating unambiguously the presence of similar com-
pounds. An analogous conclusion can be attained in the case
of complexes VII–X. The bands observed in the 266–300
and 340–360 nm regions, in all complexes studied, have been
attributed to the Mo(NNPhR) chromophore [12,17,18],
while the visible band observed in the range 376–400 nm for
the oxo-hydrazido(2y) complexes could be assigned to an
O(oxo)™Mo charge transfer transition [24]; this band is
absent in the bis-hydrazido(2y) complexes.
q1.24 V (E yEreds116 mV at 100 mV sy1), while com-
ox
pp
plex IX exhibits two quasi-reversible successive processesat
ox
q0.65 and q0.83 V (E yEreds102 and 130 mV at 100
pp
mV sy1, respectively). CV data for these primary processes
were consistent with a diffusion-controlled charge transfer
reaction; the various scans gave constant values of ipa/v1/2
and ipc/v1/2 over the range 20–300 mV sy1. Likewise,
ipa/ipc, for the anodic processes, were close to unity.
The electrochemical behavior of complex V is comparable
to that of [MoO(NNPh2)(acac)2] although, in this case, the
acetylacetonate ligands shift the reduction and oxidation
potentials to more negative values: Erpedsy1.70 V;
Eopxsq1.20 V, in DMF [17]. On the other hand, the elec-
trochemical results depicted by complex IXcanbecompared,
in general, to those observed in the phosphine complexes
formulated as [Mo(NNPhR)2Cl2(PPh3yxMex)2](R sPh,
Me; xs1, 2). However, these complexes display only one
The 1H NMR spectra of complexes III, V, VII and IX in
CDCl3 are unexceptional except the presence, in the case of
III and V, of a resonance at 5.31 ppm which confirms unam-
biguously that these complexes crystallize with one CH2Cl2
solvent molecule (vide supra). On the other hand, the spectra
of complexes IV and VI, that contain the MoO(NNMePh)
fragment, recorded in DMSO-d6 due to their very low solu-
bilities in CDCl3, exhibit three methyl proton resonances in
the 3.65–4.34 (IV) and 3.64–4.50 (VI) ppm regions. Prob-
ably, these resonances could arise (i) from the presence of
two hydrazido rotamers (two resonances) and (ii) from a
partial substitution of a chloride ligand by a DMSO solvent
molecule (one resonance); the very low intensity resonance
at 2.88 (IV) and 2.92 (VI) ppm, near to that of the free
solvent chemical shift (2.50 ppm) is probably due to that
coordinated DMSO. Likewise, the more salient feature of the
spectra of VIII and X, that contain the Mo(NNMePh)2 moi-
ety, recorded at room temperature in CDCl3, is the presence
of three methyl proton resonances in the 3.55–4.31 ppm
range, which could be explained by a mixture of two hydra-
zido rotamers in solution. The first rotamer, that contains
alternate methyl groups (inequivalent hydrazido-methyl
groups), exhibits two resonances with the same integrated
intensity at 3.64 and 4.25 (VIII), and 3.55 and 4.31 (X)
ppm, while the second, that contains inner methyl groups
(equivalent hydrazido-methyl groups), exhibitsonlyoneres-
onance at 4.11 (VIII) and 4.17 (X) ppm [5]. Considering
the integrated intensities for both complexes, the ratio inner/
alternate rotamers is 1.85 for VIII and 2.00 for X.
nearly-reversible oxidation process in the same region:
red
E
sy1.42 to y1.72 V; Eoxsq0.83 to q0.93 V, in
pp
CH2Cl2 [5].
4. Conclusions
The precedent study shows the potential of mixed [hydra-
zido(1y)][hydrazido(2y)] molybdenum complexes,
[Mo(NHNPhR)(NNPhR)(acac)Cl2]R( sMe, Ph), as
precursors of new oxo[hydrazido(2y)] and bis-[hydra-
zido(2y)] molybdenum complexes containing di-iminesas
ancillary ligands. This property is a consequence of the sus-
ceptibility of the acetylacetonate ligand that can be substi-
tuted by nucleophilic reagents [5,17,18]. The substitution is
accompanied by the deprotonation of the NHNPhR ligand,
generating the second NNPhR ligand and one Hacac mole-
cule [5]. Further studies on organometallic compounds
derived from these complexes will be discussed in forth-
coming publications.
5. Supplementary material
Lists of observed and calculated structure factors, aniso-
tropic thermal parameters, H atom parameters, and full lists
of bond distances and angles for complexes III, V and IX,
are available from D. Boys on request.
3.4. Electrochemistry
Acknowledgements
Complexes V and IX were studied by cyclic voltammetry
(CV) at a platinum electrode in dichloromethane. The num-
ber of electrons transferred in the various reduction and oxi-
dation steps was estimated to be one by comparison to the
CV of ferrocene under the same experimental conditions. In
reduction, both complexes exhibit one irreversible process at
y1.31 and y1.65 V, respectively. However, in oxidation,
complex V exhibits only one nearly-reversible process at
We acknowledge financial support from Fondo Nacional
de Desarrollo Cient´ıfico y Tecnolo´gico, FONDECYT, Grant
No. 1951088 (D.C. and C.M.), to the CONICYT-CNRS
International Agreement (D.C., C.M. and J.-R.H.), to Fun-
dacio´n Andes for funding the purchase of the Single-Crystal
Diffractometer (D.B.) and to the Direccio´n General de

80
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