Reduction of hafnium(IV) complexes in the presence of molecular nitrogen: Attempts to form dinitrogen complexes of the heaviest group 4 element

Article abstract of DOI:10.1139/v03-161

The reaction of [P₂N₂]Li₂(dioxane) ₂ with HfCl₄(THF)₂ (where [P₂N ₂] = PhP(CH₂SiMe₂NSiMe₂CH ₂)₂PPh) results in the formation of the hafnium dichloride complex [P₂N₂]HfCl₂ (1). The behaviour of 1 as a potential precursor in the generation of a dinitrogen coordination complex is described. Reduction of 1 with potassium-graphite (C₈K), under dinitrogen, under a variety of conditions led to a number of products, one of which is the dinuclear derivative with bridging P-phenyl groups that has the general formula {[P₂N ₂]Hf}₂ (2). Reduction of the hafnium diiodide [P ₂N₂]HfI₂ (3) - prepared via the reaction of 1 with excess Me₃SiI - with C₈K results in the formation of ([P₂N₂]Hf)₂(μ-η²:η ²-N₂) (4) as the major product of the reaction, while {[P₂N₂]Hf}₂ (2) and [P₂N ₂]Hf(C₇H₈) (5) appear to be minor products. Reaction of 1 with 2 equiv of MeMgCl gives [P₂N₂]HfMe ₂ (6), which, upon exposure to an atmosphere of H₂, gives the hafnium tetrahydride {[P₂N₂]Hf }₂(m-H) ₄ (7).

Full text of DOI:10.1139/v03-161

1376
Reduction of hafnium(IV) complexes in the
presence of molecular nitrogen: Attempts to form
dinitrogen complexes of the heaviest group 4
element1
Michael D. Fryzuk, James R. Corkin, and Brian O. Patrick
Abstract: The reaction of [P2N2]Li2(dioxane)2 with HfCl4(THF)2 (where [P2N2] = PhP(CH2SiMe2NSiMe2CH2)2PPh) re-
sults in the formation of the hafnium dichloride complex [P2N2]HfCl2 (1). The behaviour of 1 as a potential precursor
in the generation of a dinitrogen coordination complex is described. Reduction of 1 with potassium-graphite (C8K), un-
der dinitrogen, under a variety of conditions led to a number of products, one of which is the dinuclear derivative with
bridging P-phenyl groups that has the general formula {[P2N2]Hf}2 (2). Reduction of the hafnium diiodide [P2N2]HfI2
(3) — prepared via the reaction of 1 with excess Me3SiI — with C8K results in the formation of ([P2N2]Hf)2(µ-η2:η2-
N2) (4) as the major product of the reaction, while {[P2N2]Hf}2 (2) and [P2N2]Hf(C7H8) (5) appear to be minor prod-
ucts. Reaction of 1 with 2 equiv of MeMgCl gives [P2N2]HfMe2 (6), which, upon exposure to an atmosphere of H2,
gives the hafnium tetrahydride {[P2N2]Hf}2(m-H)4 (7).
Key words: hafnium, dinitrogen, reduction, coordination chemistry, hydride, mixed donor ligands.
Résumé : La réaction du [P2N2]Li2(dioxane)2 avec le HfCl4(THF)2 {dans lequel [P2N2] = PhP(CH2SiMe2NSiMe2CH2)2PPh}
conduit à la formation du complexe de dichlorure d’hafnium, [P2N2]HfCl2 (1). On décrit le comportement du complexe
1 comme précurseur potentiel pour générer un complexe de coordination du diazote. La déduction de 1 à l’aide de po-
tassium sur graphite (C8K), sous atmosphère de diazote, dans diverses conditions expérimentales conduit à la formation
d’un certain nombre de produits, dont l’un est un dérivé dinucléaire de formule générale {[P2N2]Hf}2 (2) portant des
groupes P-phényles agissant comme ponts. La réduction par le C8K du complexe de diiodure d’hafnium, [P2N2]HfI2
(3), préparé par le biais d’une réaction de 1 avec un excès de Me3SiI, conduit à la formation du complexe {([P2-
N2]Hf)2(µ-η2:η2-N2) (4) comme produit majeur de la réaction alors qu’il semble y avoir formation {[P2N2]Hf}2 (2) et
de [P2N2]Hf(C7H8) (5) comme sous-produits. La réaction de 1 avec deux équivalents de MeMgCl conduit à la forma-
tion de [P2N2]HfMe2 (6) qui, mis dans une atmosphère de H2, fournit le tétrahydrure d’hafnium, {[P2N2]Hf}2(µ-H)4 (7).
Mots clés : hafnium, diazote, réduction, chimie de coordination, hydrure, ligands donneurs fixés.
[Traduit par la Rédaction] Fryzuk et al. 1387
Introduction
which molecular dinitrogen complexes are not known and
the group 4 element, Hf, for which only one dinitrogen com-
plex has been reported (2). Reduction of Cp*2HfI2 with Na–
K in dimethoxyethane at –40 °C does result in the formation
of [Cp*2Hf(N2)]2(µ-N2) in rather low yields. In this case, the
choice of the reducing agent and solvent and the use of the
diiodide were critical to the success of this procedure. As
has been reported earlier, reductive strategies to generate
dinitrogen complexes can lead to other products (3), and so,
the fact that reaction optimization required considerable
variation in experimental conditions is not surprising.
In this paper we describe our efforts to extend the family
of hafnium dinitrogen complexes by the attempted prepara-
tion of ([P2N2]Hf)2(µ-η2-N2) (4), in analogy to that reported
previously for the zirconium complex ([P2N2]Zr)2(µ-η2-N2).
The zirconium complex has been shown to add H2 and pri-
mary silanes with concomitant formation of N—H and N—
Si bonds, respectively (4). We reasoned that access to the
hafnium dinitrogen complex congener might allow for simi-
lar reactivity and even perhaps different reactivity patterns.
However, as will be shown in this work, changing the metal
The preparation of dinitrogen complexes of the early tran-
sition metals generally involves reduction of some suitable
metal halide precursor in the presence of molecular nitrogen
(1). While effective in many cases, certain early transition
elements are not easily reduced, and as such, well-defined
dinitrogen complexes are either unknown or extremely rare.
Examples of this are the group 3 elements, Sc, Y, and La, for
Received 13 March 2003. Published on the NRC Research
Press Web site at http://canjchem.nrc.ca on 11 November 2003.
Dedicated to John Harrod in celebration of his contributions
to inorganic chemistry, especially early metal chemistry.
M.D. Fryzuk,2 J.R. Corkin, and B.O. Patrick. Department
of Chemistry, University of British Columbia, 2036 Main
Mall, Vancouver, BC V6T 1Z1, Canada.
1This article is part of a Special Issue dedicated to Professor
John Harrod.
2Corresponding author (e-mail: fryzuk@chem.ubc.ca).
Can. J. Chem. 81: 1376–1387 (2003)
doi: 10.1139/V03-161
© 2003 NRC Canada

Fryzuk et al.
1377
Scheme 1. Synthesis of [P2N2]HfCl2 (1).
from Zr to Hf results in a different set of reactions when re-
duction in the presence of dinitrogen is attempted.
nium analogue, [P2N2]ZrCl2, and Table 1 shows a compari-
son of selected bond lengths and angles for the two com-
pounds. As with the zirconium analogue, the Hf—N, Hf—P,
and Hf—Cl bond lengths are not unusual and compare well
with other group 4 amido and phosphine complexes (5, 11–
13).
Results and discussion
Preparation and structure of [P2N2]HfCl2 (1)
Like the zirconium derivative, the solid-state molecular
Our initial strategy to prepare ([P2N2]Hf)2(µ-η2-N2) (4)
was to follow exactly the preparation of the zirconium ana-
log ([P2N2]Zr)2(µ-η2-N2), by reduction of the Hf(IV)
dichloride complex, [P2N2]HfCl2 (1), with an alkali metal re-
agent. We have already shown that reduction of [P2N2]MClx
(M = Zr, x = 2; M = Nb, x = 1) by potassium-graphite (C8K)
can generate good yields of the corresponding dinitrogen
complexes ([P2N2]M)2(µ-N2) (M = Zr (4), M = Nb (3)). The
starting dichloride 1 was prepared by the reaction of the
THF adduct of hafnium(IV) tetrachloride with 1 equiv of
[P2N2]Li2(1,4-dioxane)2. The optimal conditions for this re-
action were found to require heating of a suspension of start-
ing materials in toluene overnight at approximately 120 °C
(Scheme 1).
1
structure of 1 does not match the solution structure. The H
NMR spectrum of 1 is virtually identical to that of the zirco-
nium analogue, with slight displacements of each character-
istic signal. The solution structure is more compatible with a
C2v symmetry. Only two signals due to the silyl methyl pro-
tons are observed, reflecting the “top and bottom” asymme-
try of 1. If the C2 symmetry of the solid state is held in
solution, one would expect to observe four silyl methyl sig-
nals. It seems, therefore, that the [P2N2] framework is quite
flexible in solution and undergoes a “rocking” motion cen-
tered at the trigonal silyl amide groups. The 31P{1H} NMR
spectrum of 1 shows a singlet at –5.8 ppm, which is shifted
8.5 ppm downfield from that observed for the zirconium an-
alogue.
1
Complex 1 was characterized by solution H and 31P{1H}
NMR spectroscopy, elemental analysis, and solid-state, X-
ray structure analysis. Crystals of 1 suitable for X-ray dif-
fraction were grown from a saturated DME solution; the
ORTEP diagram is shown in Fig. 1.
The solid-state molecular structure of 1 is best described
as distorted octahedral. N(1), N(2), Cl(1), and Cl(2) can be
described as forming a square plane, with the sum of the
four angles equal to 360.1°. P(1) and P(2) can then be de-
scribed as adopting quasi-capping positions, with a P(1)-
Hf(1)-P(2) angle of 153.76(3)°, which is drawn back from
the optimum 180° because of the constraints of the
macrocyclic ligand framework. The small cavity size of the
[P2N2] ligand forces the hafnium atom to sit atop the ligand,
which places the two chlorides cis to each other.
Reduction of [P2N2]HfCl2 (1)
While ease of reduction is difficult to compare, tables of
reduction potentials indicate that Hf is more difficult to re-
duce than zirconium (14–15). The first attempt to reduce 1
followed a procedure identical to the one that formed the zir-
conium dinitrogen complex; it involved reduction of the
starting chloride complex with 2 equiv of potassium graphite
(4), but the results were unexpected. Instead of the desired
dinitrogen complex, the major product was the hafnium
dimer, {[P2N2]Hf}2 (2), with coordination of the activated
phenyl rings on one phosphorus to the other metal atom
(Scheme 2).
The NMR spectra of 2 are consistent with this dimeric
formulation. The 1H NMR spectrum shows a set of phospho-
rus–phenyl resonances in a 2:2:1 ratio at 4.22, 4.15, and
3.39 ppm, respectively. Coupling information is transmitted
through the coordinated arene ring between metal centers,
The [P2N2] framework is distorted and adopts a C2 twist
in the solid state, a feature that has been observed in many
[P2N2] complexes (5–10). The solid-state structure of 1 is
both isomorphous and isostructural with that of its zirco-
© 2003 NRC Canada

1378
Can. J. Chem. Vol. 81, 2003
Fig. 1. An ORTEP diagram of [P2N2]HfCl2 (1), showing the solid-state molecular structure (ellipsoids at 50% probability). The silyl
methyl groups have been omitted for clarity; only the ipso carbons of the phosphorus phenyl groups are shown.
Table 1. A comparison of selected bond lengths (Å) and angles (°) in [P2N2]MCl2 (M = Zr, Hf).
Bond lengths
M = Hf
M = Zr
Bond angles
M = Hf
M = Zr
96.6(1)
153.76(3)
83.32(4)
90.88(9)
89.22(9)
96.8(2)
152.52(6)
82.57(7)
89.5(1)
M(1)—N(1)
M(1)—N(2)
M(1)—P(1)
M(1)—P(2)
M(1)—Cl(1)
M(1)—Cl(2)
2.125(3)
2.134(3)
2.684(1)
2.673(1)
2.461(1)
2.461(1)
2.136(4)
2.125(4)
2.694(2)
2.707(2)
2.455(2)
2.448(2)
N(1)-M(1)-N(2)
P(1)-M(1)-P(2)
Cl(1)-M(1)-Cl(2)
N(1)-M(1)-Cl(2)
N(2)-M(1)-Cl(1)
91.3(1)
leading to an AA′BB′ pattern in the 31P{1H} NMR spectrum.
This compound also has a zirconium analogue, {[P2N2]Zr}2,
which is the major product when [P2N2]ZrCl2 is reduced
with C8K in the absence of N2, for example, under Ar or in a
degassed vessel (3). {[P2N2]Zr}2 was first noticed as an im-
purity in the reaction that produces {[P2N2]Zr}(µ-η2:η2-N2).
For the zirconium system, under N2, the dimer was a fairly
minor impurity. When the metal center is changed to haf-
nium, the dimer appears to be the major product of this reac-
tion, at least under these conditions.
the dichloride 2. In the H NMR spectrum of the diiodide
complex, the two silyl methyl signals are now separated by
0.3 ppm, while for the dichloride complex the separation is
less than 0.05 ppm.
1
Reaction of [P2N2]HfI2 (3) with 2 equiv of C8K under
1 atm (1 atm = 101.325 kPa) of dinitrogen produced a mix-
ture of products and a solution with an intense blue color, a
color characteristic of the {[P2N2]Zr}(µ-η2:η2-N2) analogue.
These products, their tentative assignments, and their per-
centages as determined by 31P{1H} NMR spectroscopy are
summarized in Table 2.
The 31P{1H} NMR chemical shift of the speculated
dinitrogen complex, combined with the intense blue color of
the solution, was an excellent indication of dinitrogen com-
plex formation, but it remained uncertain that the signal at
–8.2 ppm could be assigned to {[P2N2]Hf}(µ-η2:η2-N2).
In an attempt to increase the yield of the dinitrogen com-
plex 4, the reaction was repeated in a sealed reactor, under
4 atm of dinitrogen, for a period of 8 days (Table 3). With
these changes in reaction conditions, the signal at –8.2 ppm
became the major signal. The large increase in integration
size of this signal, when the only change to the reaction was
to increase the N2 pressure, is further evidence that the sig-
nal can be assigned to the dinitrogen complex. However, a
Preparation and reduction of [P2N2]HfI2 (3)
The only known hafnium dinitrogen complex,
{Cp* Hf(N2)}2(µ-N2), was prepared from the precursor,
2
Cp* HfI2, after attempts to use a dichloride complex as a
2
starting material were unsuccessful (2). Reaction of a tolu-
ene solution of [P2N2]HfCl2 (1) with a slight excess of
trimethylsilyliodide resulted in formation of [P2N2]HfI2 (3)
(Scheme 3).
Assuming an analogous structure for the diiodide as was
found for the dichloride, one would expect little change in
the NMR spectra upon replacement of chloride with iodide,
and to a degree this is observed. The 31P{1H} NMR signal is
still a singlet at –5.4 ppm, shifted only 0.4 ppm downfield of
© 2003 NRC Canada

Fryzuk et al.
1379
Scheme 2. Synthesis of {[P2N2]Hf}2 (2).
Scheme 3. Synthesis of [P2N2]HfI2 (3).
Further characterization of {[P2N2]Hf}2(µ-η2:η2-N2) (4)
Further evidence for the formation of complex 4 comes
from mass spectrometry data. Shown in Fig. 2 is a portion of
the EI mass spectrum. Figure 3 shows the theoretical mass
higher percentage of starting material remains when com-
pared with the same reaction using 1 atm of N2, and the
other impurities are still present, although in smaller
amounts.
© 2003 NRC Canada

1380
Can. J. Chem. Vol. 81, 2003
Table 2. The results of a study of the reaction of [P2N2]HfI2 (3) with 2 equiv of C8K under 1 atm N2 in toluene.
Compound
31P shift (ppm)
After 1 h (%)a
After 4 h (%)
After 8 h (%)
After 25 h (%)
After 72 h (%)
5
34
33
29
[P2N2]HfI2 3
–5.4 (s)
6.3 (m)b
8.6 (s)
100
0
77
9
55
21
14
9
31
26
22
21
{[P2N2]Hf}2 2
[P2N2]Hf(C7H8) 5
{[P2N2]Hf}2(µ-N2) 4
0
8
–8.2 (s)
0
6
aPercentages of each compound determined from integration of their 31P{1H} NMR signals. Error is approximately 1% for each.
bSpin system is AA′BB′.
Table 3. The results of a study of the reaction of [P2N2]HfI2 (3) with 2 equiv of C8K under 4 atm N2 in toluene.
[P2N2]HfI2 3
{[P2N2]Hf}2 2
6.3 (m)a
16
[P2N2]Hf(C7H8) 5
{[P2N2]Hf}2(µ-N2) 4
31P shift (ppm)
After 8 days under 4 atm N2 (%)b
–5.4 (s)
19
–8.2 (s)
52
8.6 (s)
13
aSpin system is AA′BB′.
bPercentages of each compound determined from integration of their 31P{1H} NMR signals. Error is approximately 1% for each.
Fig. 2. Selected EI mass spectrometry data for ([P2N2]Hf)2N2 (4).
Fig. 3. Theoretical isotope distribution pattern for EI mass spectrometry analysis of ([P2N2]Hf)2N2 (4), as determined by Isotope Pat-
tern Calculator™ v. 1.6.6.
spectrometry signature one would expect from complex 4.
The theoretical signature is a near exact match for the exper-
imental one shown in Fig. 2. In Fig. 2, signatures for
{[P2N2]Hf}2N (where a single nitrogen atom has been
stripped from the parent compound) and for {[P2N2]Hf}2 (2)
can also be seen and are labeled.
Not shown here, but also observed in the EI mass spec-
trum, are the signatures for [P2N2]Hf(C7H8) (5) and for
© 2003 NRC Canada

Fryzuk et al.
1381
Scheme 4. Synthesis of [P2N2]HfMe2 (6).
[P2N2]HfI and [P2N2]Hf. Interestingly, no signature is ob-
served for [P2N2]HfI2 (3), likely because of the weakness of
the Hf—I bond.
mononuclear group 4 metal [P2N2] complexes, the dimethyl
compound adopts C2v symmetry in solution at ambient tem-
perature, as evidenced by NMR spectroscopy. As expected,
the methyl protons are coupled to two equivalent phospho-
rus nuclei and appear as a triplet at 0.65 ppm. Unlike the
case of the zirconium analogue, their signal is not masked
by the [P2N2] ligand methylene protons. Interestingly, while
it was not possible to grow crystals of the zirconium ana-
logue of this compound, crystals of the hafnium analogue
were grown easily from slow evaporation of a DME solu-
tion. An ORTEP diagram of complex 6 is shown in Fig. 4.
The substitution of methyl groups for chloride moieties upon
going from 1 to 6 has resulted in a substantial structural
change. The geometry around the metal center is now best
described as trigonal prismatic, with the two trigonal planes
described by N(1), P(1), and C(25) and N(2), P(2), and
C(26). The methyl carbons are not located in a square plane
with the amido nitrogens but are rotated out of this plane. As
well, the phosphine and amide “bite angles”, P(1)-Hf-P(2)
and N(1)-Hf-N(2), have both changed considerably. The
phosphine bite angle has decreased from 153.76(3)° to
135.79(3)°, while the amide bite angle has increased from
96.6(1)° to 113.2(1)°. Table 4 shows selected bond distances
and angles for complex 6. The Hf—C, Hf—N, and Hf—P
bond distances are, once again, not unusual and compare
well with other group 4 methyl complexes (11).
To confirm the presence of a dinitrogen compound in the
products from the reaction of [P2N2]HfI2 (3) with 2 equiv of
C8K, the mixture of products was degraded with HCl and
the resultant products analyzed to detect hydrazine, accord-
ing to literature procedure (16). Hydrazine was detected,
confirming the presence of a dinitrogen compound; however,
it was not possible to determine the percent of hydrazine
formed per mole of {[P2N2]Hf}2(µ-η2:η2-N2) (4), owing to
the inability to isolate 4 in pure form.
Preparation and structure of [P2N2]HfMe2 (6)
We were also interested in the organometallic chemistry
of hafnium with the [P2N2] ligand. {[P2N2]Zr}2(µ-H)4 was
prepared3 from [P2N2]ZrCl2, using C8K as a reducing agent,
under 4 atm of H2. Interestingly, it does not appear to be
possible to form a zirconium hydride from [P2N2]ZrMe2.
[P2N2]ZrMe2 is extremely thermally and light sensitive,
making it difficult to prepare in sufficient quantities to use in
subsequent reactions. It is a well-established precedent that
certain organometallic hafnium(IV) compounds are more
thermally stable than their zirconium analogues (12, 17–19).
As well, the use of hafnium analogues can facilitate investi-
gation of intermediates in cases where this proves difficult
for zirconium compounds (2, 20, 21). The synthesis of
[P2N2]HfMe2 (6) was accomplished by the metathesis reac-
tion of [P2N2]HfCl2 (1) with 2 equiv of the Grignard re-
agent, MeMgCl (Scheme 4).
Preparation of {[P2N2]Hf}(µ-H)4 (7)
While hydrogenolysis of [P2N2]ZrMe2 did not result in a
zirconium hydride complex, a hafnium hydride was synthe-
sized through hydrogenolysis. Reaction of P2N2HfMe2 with
H2 gas in benzene gave {[P2N2]Hf}2(µ-H)4 7 (Scheme 5).
Complex 7 is sparingly soluble in benzene and precipitates
1
Compound 6 was characterized by H and 31P{1H} NMR
spectroscopy, elemental analysis, and X-ray crystal structure
analysis. In a manner similar to most other known
3 M.D. Fryzuk and J.B. Love. Unpublished results.
© 2003 NRC Canada

1382
Can. J. Chem. Vol. 81, 2003
Fig. 4. An ORTEP diagram showing the solid-state molecular structure of [P2N2]HfMe2 (6) (ellipsoids at 50% probability). The silyl
methyl groups have been omitted for clarity; only the ipso carbons of the phosphorus phenyl groups are shown.
to the iodide complex did result in the formation of the haf-
Table 4. Selected bond lengths (Å) and angles (°) in [P2N2]HfMe2
(6).
nium dinitrogen complex, {[P2N2]Hf}(µ-η2:η2-N2) (4), after
reduction with C8K, as shown by NMR spectroscopy, EI
mass spectrometry, and hydrazine analysis. Unfortunately, it
has not been possible to isolate compound 4 in the solid
state. Synthesis of [P2N2]HfMe2 (6) proceeded in a manner
identical to that of its zirconium analogue. The dimethyl de-
rivative, 6, reacts with H2 to generate the dinuclear hafnium
hydride, {[P2N2]Hf}(µ-H)4 (7), via hydrogenolysis; this re-
action fails for the zirconium analogue, [P2N2]ZrMe2.
Bond lengths
Bond angles
Hf(1)—N(1)
Hf(1)—N(2)
Hf(1)—P(1)
Hf(1)—P(2)
Hf(1)—C(25)
Hf(1)—C(26)
2.147(3)
2.149(3)
2.781(1)
2.783(1)
2.263(1)
2.277(1)
N(1)-Hf(1)-N(2)
P(1)-Hf(1)-P(2)
C(25)-Hf(1)-C(26)
N(1)-Hf(1)-C(25)
N(2)-Hf(1)-C(25)
113.5(1)
135.79(3)
82.0(2)
97.2(2)
134.6(2)
out of solution as yellow microcrystals, making separation
from the parent compound a simple matter.
Experimental
The change in the chemical shift of the phosphorus nuclei,
when switching from {[P2N2]Zr}2(µ-H)4 to its hafnium ana-
logue,3 is more drastic than in other [P2N2] compounds. The
signal is observed at 4.4 ppm, downfield from the zirconium
analogue signal at –5.9 ppm. As well, the hydride quintet (2,
22–24) is observed at 9.3 ppm, downfield from 5.0 ppm in
the zirconium analogue. The other characteristic signals in
Materials and apparatus
All manipulations were performed under prepurified nitro-
gen in a Vacuum Atmospheres HE-553-2 workstation
equipped with an MO-40-2H purification system or using
Schlenk-type glassware. The term “reactor” refers to a cylin-
drical, thick-walled Pyrex vessel equipped with a 5 mm (or
10 mm, for larger bombs) Kontes teflon needle valve and a
ground glass joint for attachment to a vacuum line. These
“reactors” allow pressures as high as 4 atm to be maintained
inside the tube. HfCl4 (<0.05% Zr) was purchased from
Strem and used as received. THF was predried by refluxing
over CaH2 for at least 24 h and dried by refluxing over so-
dium benzephenone ketyl, followed by distillation under ar-
gon. Toluene and hexanes were purchased in anhydrous
form from Aldrich, sparged with N2, and deoxygenated by
filtration through columns containing silica and Q-5 catalyst
under a positive pressure of N2 (25). Benzene, diethyl ether,
and dimethoxyethane were also refluxed over sodium
benzephenone ketyl and distilled under argon. Deuterated
THF (C4D8O) and deuterated benzene (C6D6) were refluxed
under vacuum with sodium–potassium amalgam (Na–K),
1
the H NMR spectrum have not changed appreciably.
Conclusions
The hafnium chemistry presented in this paper, while sim-
ilar to the previously reported zirconium chemistry, does
have some notable differences. Although the X-ray crystal
structure of [P2N2]HfCl2 (1) is isostructural and
isomorphous with that of its zirconium analogue, the reactiv-
ity of 1, especially under reducing conditions, is quite differ-
ent. It was not possible to synthesize the hafnium dinitrogen
compound {[P2N2]Hf}(µ-η2:η2-N2), in any appreciable
amount, from [P2N2]HfCl2 (1); instead, a hafnium dimer,
{[P2N2]Hf}2 (2), was the major product. However, changing
the hafnium starting material from the chloride complex, 1,
© 2003 NRC Canada

Fryzuk et al.
1383
Scheme 5. Synthesis of {[P2N2]Hf}2(µ-H)4 (7).
vacuum transferred to a clean vessel, and “freeze–pump–
thawed” three times prior to use.
tures were determined at UBC Crystallographic Services in
this department by Dr. B. Patrick. The crystals were loaded
in a small glass vial and covered with paratone oil in the
glovebox to prevent decomposition. Details of the structure
determinations are given in the Appendices.4
The following compounds were prepared by published
procedures: HfCl4(THF)2 (26), [syn-P2N2]Li2(dioxane) (27),
C8K (28), and Mg(C4H6)(THF)2. Me3SiI, MeMgCl,
BzMgCl, and H2 were used as received. Diatomaceous earth
(Celite) was dried overnight at 170 °C before being taken in-
side the glovebox for use.
Hydrazine analysis (16)
The products from the reaction of [P2N2]HfI2 (3) with 2
equiv of C8K were weighed into a 200 mL Schlenk tube
(0.280 g) and dissolved in 50 mL of Et2O. Ten millilitres of
2.0 mol L–1 HCl in Et2O was added to this solution. The so-
lution immediately lost its blue color, and a white precipitate
formed. The clear solution and white precipitate were stirred
for 1 h, and the solvents were removed in vacuo. The flask
was exposed to the air, extracted into 100 mL of H2O, and
filtered into a 500 mL volumetric flask, which was
filled with 1.0 mol L–1 HCl. A 2.0 mL aliquot of this
solution was added to 20 mL of a color developer (p-
dimethylaminobenzaldehyde, 4.0 g; ethanol, 200 mL;
1.0 mol L–1 HCl, 20 mL) and diluted to 25.0 mL with
1.0 mol L–1 HCl. Absorbance readings of the sample were
taken within 10 min. The spectrometer was set to 100%
Analytical methods
1H and 31P{1H} NMR spectroscopy were performed on a
Bruker AMX-500 instrument (500.135 and 202.458 MHz) or
1
a Bruker AC-200 machine (200.132 and 81.015 MHz). H
NMR spectra were referenced to internal C6D5H (7.15 ppm),
and 31P{1H} NMR spectra were referenced to external
P(OMe3)3 (141.0 ppm, with respect to 85% H3PO4 at
0.00 ppm).
The theoretical EI signature was created using Isotope™
v. 1.6.6, a program designed specifically to model mass
spectrometry signatures.
C, H, and N microanalyses were performed by Mr. P.
Borda of this department, the Department of Chemistry, Uni-
versity of British Colombia (UBC). The X-ray crystal struc-
transmittance, using
a
blank solution consisting of
4 Supplementary data may be purchased from the Depository of Unpublished Data, Document Delivery, CISTI, National Research Council
Canada, Ottawa, ON K1A 0S2, Canada (http://www.nrc.ca/cisti/irm/unpub_e.shtml for information on ordering electronically). CCDC
205941 and 205942 contain the supplementary data for this paper. These data can be obtained, free of charge, via
www.ccdc.cam.ac.uk/conts/retrieving.html (or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge, U.K.; fax
+44 1223 336033; or deposit@ccdc.cam.ac.uk).
© 2003 NRC Canada

1384
Can. J. Chem. Vol. 81, 2003
1.0 mol L–1 HCl. Absorbance readings of 0.33, 0.34, and
0.33 AU were obtained at 458 nm.
SiMe2 ring), 0.39 (s, 12H, SiMe2 ring). 31P{1H} (C6D6, 25 °C,
81.015 MHz) δ: –5.4 (s). Anal. calcd. for C24H42I2HfN2P2Si4:
C 29.87, H 4.39, N 2.90; found: C 30.02, H 4.43, N 2.89.
Synthesis of [P2N2]HfCl2 (1)
Attempted synthesis of {[P2N2]Hf}2(µ-η2:η2-N2) (4)
Li2(dioxane)[P2N2] (6.83 g, 10.8 mmol) and HfCl4(THF)2
(5.00 g, 10.8 mmol) were each weighed into a thick-walled
reactor. Addition of 150 mL toluene to this intimate mixture
resulted in a cloudy white solution. The reactor was sealed,
and the mixture was heated for 18 h at 120 °C. The solvents
were then removed in vacuo; the off-white residue was ex-
tracted into toluene (2 × 50 mL) and filtered through Celite.
The filtrate was evaporated to dryness and the residue
washed with hexanes (2 × 10 mL), yielding 1 (7.25 g, 86%)
as a white powder. The product was crystallized by the slow
evaporation of a DME solution.
C8K (0.33 g, 3.32 mmol) and [P2N2]HfI2 (3) (1.21 g,
1.26 mmol) were each weighed into a 200 mL thick-walled
reactor, to which 50 mL of toluene was added, all in the
glovebox. The reactor was removed from the glovebox and
cooled to –198 °C in a liquid nitrogen bath while under a
flow of N2. After allowing 30 min for equilibration, the reac-
tor was sealed and allowed to warm to room temperature.
Following 16 h of stirring, a blue-purple color was observed.
The reactor was then allowed to stir vigorously for another
7 days. The solution was then filtered through Celite and
evaporated to dryness. Washing with a minimal amount of
hexanes (2 × 10 mL) yielded 0.85 g of a dark solid. 31P{1H}
NMR indicates the composition of this solid to be approxi-
mately 52% 4, 19% 3, 16% 2, and 13% 5. EI-MS: 1450 ([M]+).
1H NMR (C6D6, 25 °C, 500.135 MHz) δ: 7.87 (m, 4H, o-
H phenyl), 7.05 (m, 6H, m/p-H phenyl), 1.41 (ABX m, 4H,
CH2 ring), 1.32 (ABX m, 4H, CH2 ring), 0.38 (s, 12H,
SiMe2 ring), 0.34 (s, 12H, SiMe2 ring). 31P{1H} (C6D6,
25 °C, 202.458 MHz) δ: –5.8 (s). Anal. calcd. for
C24H42Cl2HfN2P2Si4: C 36.85, H 5.41, N 3.58; found: C
37.04, H 5.48, N 3.56.
Synthesis of [P2N2]HfMe2 (6)
To a solution of [P2N2]HfCl2 (1) (3.02 g, 3.86 mmol) in
THF was added 3.0 mol L–1 MeMgCl in THF (2.57 mL,
7.77 mmol) at 0 °C. The solution was warmed to room tem-
perature and stirred for 1 h, after which the solvents were
evaporated in vacuo. The off-white residue was extracted
into toluene (2 × 20 mL) and filtered through celite. The fil-
trate was evaporated to dryness, and the residue was washed
with hexanes (2 × 10 mL), yielding 6 (2.24 g, 77%) as a
white powder. The product was crystallized by the slow
evaporation of a DME solution.
Synthesis of {[P2N2]Hf}2 (2)
[P2N2]HfCl2 (1) (0.73 g, 0.93 mmol) and C8K (0.25 g,
1.86 mmol) were each weighed into a 200 mL thick-walled
reactor, to which 50 mL of toluene was added, all in the
glovebox. The reactor was removed from the glovebox and
cooled to –198 °C in a liquid nitrogen bath while under a
flow of N2. After allowing 30 min for equilibration, the reac-
tor was sealed and allowed to warm to room temperature.
The reaction mixture was stirred for 8 days and filtered
through Celite. Toluene was removed in vacuo, and the resi-
dues were dissolved in hexanes and filtered. The hexanes so-
lution was left in a –40 °C freezer overnight, where 2
crashed out of solution as a yellow-brown powder. Yield:
0.22 g, 32.2%. Note: further studies showed that it does not
matter what type of atmosphere (N2, Ar, or near vacuum) is
inside the reactor.
1H NMR (C6D6, 25 °C, 500.135 MHz) δ: 7.62 (m, 4H, o-
H phenyl), 7.07 (m, 6H, m/p-H phenyl), 1.03 (m, 8H, CH2
ring), 0.72 (t, 6H, Zr-CH3), 0.22 (s, 12H, SiMe2 ring), 0.20
(s, 12H, SiMe2 ring). 31P{1H} (C6D6, 25 °C, 202.458 MHz)
δ: –9.6 (s). Anal. calcd. for C26H48HfN2P2Si4: C 42.12, H
6.53, N 3.78; found: C 42.14, H 6.52, N 3.74.
Synthesis of {[P2N2]Hf}2(µ-H4) (7)
1H NMR (C6D6, 25 °C, 200.132 MHz) δ: 7.40 (m, 4H, o-
H phenyl), 7.10 (m, 6H, m/p-H phenyl), 4.22 (m, 4H, m/p-H
activated phenyl), 4.15 (m, 4H, m/p-H activated phenyl),
3.39 (m, 2H, o-H activated phenyl), 1.49 (ABX m, 8H, CH2
ring), 1.15 (ABX m, 8H, CH2 ring), 0.52 (s, 12H, SiMe2
ring), 0.50 (s, 12H, SiMe2 ring), 0.31 (s, 12H, SiMe2 ring),
0.04 (s, 12H, SiMe2 ring). 31P{1H} (C6D6, 25 °C,
81.015 MHz) δ: –6.3 (m). Anal. calcd. for
C48H84Hf2N4P4Si8: C 40.52, H 5.95, N 3.95; found: C 40.39,
H 5.97, N 3.75.
Fifty millilitres of C6H6 was added to 1.02 g (1.3 mmol)
of [P2N2]HfMe2 (6) in a reactor, which was sealed. The reac-
tor was “freeze–pump–thawed” three times to remove all
gases. H2 was introduced to the reactor, which was cooled to
–198 °C. After the solvent had thawed, but prior to warming
to room temperature, the reactor was shaken to promote dis-
solution of H2 in the solution. The reactor was left overnight,
during which time a microcrystalline yellow solid precipi-
tated. This solid was collected on a frit, yielding 7 (0.345 g,
37.2%).
1H NMR (C6D6, 25 °C, 500.135 MHz) δ: 9.07 (quintet,
2JHP = 4.43 Hz, 4H, Hf-H), 7.19 (m, 8H, o-H phenyl), 7.12
(m, 12H, m/p-H phenyl), 0.83 (m, 16H, CH2 ring), 0.04 (s,
24H, SiMe2 ring), –0.03 (s, 24H, SiMe2 ring). 31P{1H}
(C6D6, 25 °C, 202.458 MHz) δ: 4.4 (s). Anal. calcd. for
C48H88HfN2P2Si4: C 40.41, H 6.22, N 3.93; found: C 40.56,
H 6.21, N 3.76.
Synthesis of [P2N2]HfI2 (3)
Me3SiI (10.0 mL, 70 mmol, ~10 equiv) was added to a
stirred solution of [P2N2]HfCl2 (1) (5.21 g, 6.66 mmol) in
80 mL of toluene at –78 °C. The reactor was sealed and the
solution stirred for 18 h, during which time the solution ac-
quired a very pale yellow-green color. Toluene was removed
in vacuo and the residues washed with hexanes (2 × 10 mL),
yielding 3 (2.8 g, 88%) as a very pale green powder.
1H NMR (C6D6, 25 °C, 200.132 MHz) δ: 7.92 (m, 4H, o-
H phenyl), 7.05 (m, 6H, m/p-H phenyl), 1.58 (ABX m, 4H,
CH2 ring), 1.27 (ABX m, 4H, CH2 ring), 0.48 (s, 12H,
Acknowledgements
The authors thank the Natural Sciences and Engineering
Research Council of Canada (NSERC) for funding (Discov-
© 2003 NRC Canada

Fryzuk et al.
1385
13. D.G. Black, D.C. Swenson, and R.F. Jordan. Organometallics,
12, 3539 (1995).
14. D.J. Cardin, M.F. Lappert, and C.L. Raston. Chemistry of
organo-zirconium and hafnium compounds. Ellis Horwood
Limited, West Sussex. 1986. p. 21.
ery Grant to M.D.F.), Mr. Marshall Lapawa for mass spec-
trometry, and Mr. Peter Borda for elemental analyses.
References
15. D.F. Shriver, P. Atkins, and C.H. Langford. Inorganic chemis-
try. W.H. Freeman and Company, New York. 1994.
16. G.W. Watt and J.D. Chrisp. Anal. Chem. 24, 2006 (1952).
17. G.A. Helmut, F.P.D. Sanzo, M.D. Rausch, and P.C. Uden. J.
Organomet. Chem. 107, 257 (1976).
1. M.D. Fryzuk and S.A. Johnson. Coord. Chem. Rev. 200–202,
379 (2000).
2. D.M. Roddick, M.D. Fryzuk, P.F. Seidler, G.L. Hillhouse, and
J.E. Bercaw. Organometallics, 4, 97 (1985).
3. M.D. Fryzuk, C. Kozak, P. Mehrkhodavandi, L. Morello, B.O.
Patrick, and S. Rettig. J. Am. Chem. Soc. 124, 516 (2002).
4. M.D. Fryzuk, J.B. Love, S.J. Rettig, and V.G. Young. Science
(Washington, D.C.), 275, 1445 (1997).
5. M.D. Fryzuk, J.B. Love, and S.J. Rettig. Organometallics, 17,
846 (1998).
18. G.A. Razuvaev, L.I. Vyshinskaya, and V.P. Mar′in. Dokl.
Akad. Nauk SSSR, 225, 827 (1975).
19. G.A. Razuvaev, V.P. Mar′in, O.N. Drushkov, and L.I.
Vyshinskaya. J. Organomet. Chem. 231, 125 (1982).
20. D.M. Roddick and J.E. Bercaw. Chem. Ber. 122, 1579 (1989).
21. J.E. Bercaw and J.R. Moss. Organometallics, 11, 639 (1992).
22. M.D. Fryzuk, S.J. Rettig, A. Westerhaus, and H.D. Williams.
Inorg. Chem. 24, 4316 (1985).
6. M.D. Fryzuk, D.B. Leznoff, S.F. Ma, S.J.Rettig, and J.V.G.
Young. Organometallics, 17, 2313 (1998).
7. M.D. Fryzuk, T.S. Haddad, M. Murugesapilla, D.H.
McConville, and S.J. Rettig. J. Am. Chem. Soc. 115, 2782
(1993).
23. J.E. Gozum and G.S. Girolami. J. Am. Chem. Soc. 113, 3829
(1991).
24. J.E. Gozum, S.R. Wilson, and G.S. Girolami. J. Am. Chem.
8. M.D. Fryzuk, M. Mylvaganam, M.J. Zawarotko, and L.R.
MacGillivray. J. Am. Chem. Soc. 115, 10 360 (1993).
9. M.D. Fryzuk, S.A. Johnson, and S.J. Rettig. Organometallics.
18, 4059 (1999).
Soc. 114, 9483 (1992).
25. A.B. PangBorn, M.A. Giardello, R.H. Grubbs, R.K. Rosen,
and F.J. Timmers. Oganometallics, 15, 1518 (1996).
26. L.E. Manzer. Inorg. Chem. 21, 135 (1982).
27. M.D. Fryzuk, J.B. Love, and S.J. Rettig. J. Chem. Soc. Chem.
Commun. 2783 (1996).
10. M.D. Fryzuk, P.A. Macneil, S.J. Rettig, A.S. Secco, and J.
Trotter. Organometallics, 1, 918 (1982).
11. M.D. Fryzuk, T.S. Haddad, and D.J. Berg. Coord. Chem. Rev.
99, 137 (1990).
28. D.E. Bergbreiter and J.M. Killough. J. Am. Chem. Soc. 100,
2126 (1978).
12. M.D. Fryzuk and A. Carter. Organometallics, 11, 469 (1992).
Appendix A. X-ray crystallographic analysis of [P2N2]HfCl2 (1).
Table A1. Crystal data.
Table A2. Intensity measurements.
Empirical formula
Formula weight
Temperature (K)
Crystal color, habit
Crystal dimensions (mm)
Crystal system
Lattice type
Lattice parameters
a (Å)
C24H42N2Cl2HfP2Si4
782.29
173
Clear, chip
0.15 × 0.15 × 0.15
Orthorhombic
Primitive
Diffractometer
Radiation
Rigaku/ADSC CCD
Mo Kα (λ = 0.71069 Å)
Graphite monochromated
94 × 94
464 exposures @ 35.0 s
0.0–190.0
–19.0 to 23.0
40.62
–5.55
Detector aperture (mm)
Data images
φ Oscillation range (χ = 0) (°)
ω Oscillation range (χ = 90.0) (°)
Detector position (mm)
Detector swing angle (°)
2θmax (°)
9.3152(8)
16.5962(5)
21.3811(7)
3305.5(2)
P212121 (#19)
4
1.572
1568.00
35.71
b (Å)
c (Å)
V (Å3)
55.8
No. of reflections measured
Total: 28 469
Unique: 3999 (Rint = 0.066)
Lorentz-polarization
Absorption
Space group
Z value
Corrections
Dcalcd (g cm–3)
F000
Trans. factors
0.7796–1.0000
µ (cm–1) (Mo Kα)
© 2003 NRC Canada

1386
Can. J. Chem. Vol. 81, 2003
Table A4. Atomic coordinates and Beq.
Table A3. Structure solution and refinement.
Structure solution
Patterson methods
Atom
x
y
z
Beq
(DIRDIF92 PATTY)
0.08378(2)
0.16637
0.10928(9)
0.21020(10) 3.97(5)
Hf(1)
Cl(1)
Cl(2)
P(1)
0.97608(1)
0.94810(10)
0.84100(10)
1.08273(8)
0.92249(9)
1.06481(9)
0.91470(10)
1.10590(10)
1.15670(10)
0.9895(3)
1.0873(3)
1.1375(3)
0.8657(3)
1.0166(4)
1.1472(4)
1.1290(4)
1.0193(4)
0.8358(4)
0.9541(5)
1.1226(5)
1.1929(4)
1.1444(4)
1.2639(4)
1.0671(4)
1.1332(4)
1.1212(5)
1.0448(5)
0.9799(6)
0.9908(4)
0.8646(3)
0.8336(4)
0.7831(4)
0.7645(4)
0.7964(4)
0.8465(4)
0.890(4)
2.77(3)
Refinement
Function minimized
Full-matrix least-squares
–0.1402(2)
0.0421(2)
–0.031(10)
0.2891(2)
0.2845(2)
0.4049(2)
0.2511(2)
–0.0373(2)
0.2724(5)
0.1025(5)
0.1310(6)
0.4056(7)
0.3793(6)
–0.1363(6)
0.4503(6)
0.2705(7)
0.3787(8)
0.5897(8)
0.1921(9)
0.3649(8)
–0.1725(8)
0.0260(8)
–0.1222(5)
–0.1755(6)
–0.2378(7)
–0.2492(9)
–0.1970(8)
–0.1333(7)
0.2695(6)
0.3915(6)
0.3749(7)
0.2399(7)
0.1195(7)
0.1341(6)
Σω(|Fo | – |Fc |)2
2
2
2
Least squares weights
p-factor
Anomalous dispersion
No. observations (I > 0.00σ(I))
No. variables
Reflection:parameter ratio
Residuals (on F2, all data) R; Rw
Goodness of fit indicator
Max shift/error in final cycle
No. observations (I > 3σ(I))
Residuals (on F, I > 3σ(I)) R; Rw
ω = 1/[σ2(Fo )]
0.0000
0.24618(7)
0.08962(7)
0.27779(7)
0.22206(7)
0.06974(8)
0.11763(8)
0.2213(2)
0.1169(2)
0.2661(3)
0.1413(3)
0.0711(3)
0.1955(3)
0.2742(3)
0.3573(3)
0.2832(3)
0.2343(4)
–0.0131(3)
0.0946(4)
0.0533(3)
0.1142(3)
0.3204(2)
0.3539(3)
0.4124(3)
0.4370(3)
0.4043(3)
0.3454(3)
0.0184(3)
–0.0127(3)
–0.0635(3)
–0.0857(3)
–0.0571(3)
–0.0049(3)
1.10(3)
1.38(3)
1.19(3)
1.69(3)
1.72(3)
1.62(3)
1.21(8)
1.39(8)
1.21(9)
1.8(1)
2.3(1)
1.7(1)
2.4(1)
2.3(1)
2.9(2)
3.6(2)
3.4(2)
2.8(2)
2.8(2)
2.6(1)
1.4(1)
2.1(1)
2.9(1)
3.4(1)
3.4(2)
2.3(1)
1.5(1)
2.0(1)
2.1(1)
2.0(1)
2.3(1)
1.9(1)
P(2)
All non-hydrogen atoms
6846
316
21.66
0.036; 0.055
0.51
0.00
5913
0.020; 0.025
Si(1)
Si(2)
Si(3)
Si(4)
N(1)
N(2)
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(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
Max peak in final difference map (e Å–3) 0.68
Min peak in final difference map (e Å–3) –1.10
© 2003 NRC Canada

Fryzuk et al.
1387
Appendix B. X-ray crystallographic analysis of [P2N2]HfMe2 (6).
Table B1. Crystal data.
Table B3. Structure solution and refinement.
Empirical formula
C26H48HfN2P2Si4
Structure solution
Direct methods (SIR97)
Full-matrix least-squares
Formula weight
Temperature (K)
Crystal color, habit
Crystal dimensions (mm)
Crystal system
Lattice type
Lattice Parameters
a (Å)
b (Å)
741.46
173
Clear, block
0.30 × 0.30 × 0.10
Monoclinic
Primitive
Refinement
Function minimized
Σω(|Fo | – |Fc |)2
2
2
ω = 1/[σ2(Fo )]
2
Least squares weights
p-factor
Anomalous dispersion
No. observations (I > 0.00σ(I))
No. variables
0.0000
All non-hydrogen atoms
7219
316
22.84
0.048; 0.107
1.47
0.06
6957
11.3209(7)
10.8041(3)
28.1451(9)
3441.6(2)
Reflection:parameter ratio
Residuals (on F2, all data) R; Rw
Goodness of fit indicator
Max shift/error in final cycle
No. observations (I > 3σ(I))
Residuals (on F, I > 3σ(I)) R; Rw
c (Å)
V (Å3)
Space group
P21/n (#14)
Z value
Dcalcd (g cm–3)
4
0.036; 0.063
Max peak in final difference map (e Å–3) 1.35
Min peak in final difference map (e Å–3) –1.37
1.431
F000
1504.00
32.75
µ (cm–1) (Mo Kα)
Table B4. Atomic coordinates and Beq.
Atom
x
y
z
Beq
Table B2. Intensity measurements.
0.23340(1)
0.03890(9)
0.43630(9)
0.28500(1)
Hf(1)
P(1)
P(2)
Si(1)
Si(2)
Si(3)
Si(4)
N(1)
N(2)
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(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
0.65750(1)
0.50370(1)
0.74380(9)
0.38980(1)
0.73980(1)
0.79260(1)
0.51990(1)
0.51010(3)
0.73090(3)
0.42520(4)
0.58270(4)
0.73360(3)
0.63670(4)
0.36070(6)
0.25150(5)
0.80190(5)
0.82610(5)
0.74710(5)
0.95660(5)
0.57740(6)
0.38170(6)
0.39430(4)
0.27350(4)
0.19700(5)
0.23790(6)
0.35790(5)
0.43600(4)
0.88480(3)
0.95490(4)
1.05610(5)
1.08800(4)
1.02030(5)
0.92130(4)
0.59360(5)
0.83120(5)
0.65160(5)
0.63100(4)
0.60230(3)
0.59870(5)
0.60430(5)
0.54750(4)
0.64240(5)
0.62890(1)
0.59540(1)
0.58290(1)
0.60400(2)
0.54440(1)
0.60220(2)
0.53980(2)
0.63280(3)
0.66420(2)
0.56060(3)
0.48850(2)
0.55270(2)
0.70410(2)
0.63480(3)
0.66870(2)
0.65940(2)
0.69140(2)
0.73160(2)
0.74110(2)
0.70970(2)
0.60590(1)
0.56660(2)
0.57160(2)
0.61520(2)
0.65420(2)
0.64960(2)
0.72540(2)
0.69210(2)
1.428(4)
1.93(2)
1.56(2)
2.14(2)
2.23(2)
1.87(2)
2.51(3)
1.78(7)
1.92(7)
2.36(9)
2.45(9)
1.91(8)
3.0(1)
4.6(1)
4.1(1)
4.1(1)
4.9(2)
3.9(1)
3.5(1)
4.7(1)
4.9(2)
2.44(9)
3.5(1)
4.8(2)
4.9(2)
4.8(2)
3.4(1)
1.76(8)
2.8(1)
3.4(1)
2.7(1)
3.3(1)
3.2(1)
3.5(1)
3.6(1)
Diffractometer
Radiation
Rigaku/ADSC CCD
Mo Kα (λ = 0.71069 Å)
Graphite monochromated
94 × 94
772 exposures @ 16.0 s
0.0–189.9
–19.0 to 23.0
40.47(1)
–5.52(1)
–0.03330(1)
0.19670(1)
0.50130(1)
0.34560(3)
0.12540(3)
0.11840(4)
–0.09030(4)
0.36020(4)
0.56280(4)
0.36310(6)
0.29060(6)
–0.06790(5)
–0.12370(5)
0.12780(5)
0.20020(5)
0.52430(6)
0.59320(5)
–0.03090(4)
–0.02800(5)
–0.08220(7)
–0.14090(7)
–0.14420(7)
–0.08990(5)
0.51510(4)
0.53830(5)
0.60970(5)
0.66040(5)
0.63620(5)
0.56220(5)
0.19070(5)
0.26530(5)
Detector aperture (mm)
Data images
φ Oscillation range (χ = 0) (°)
ω Oscillation range (χ = 90.0) (°)
Detector position (mm)
Detector swing angle (°)
2θmax (°)
55.8
No. of reflections measured
Total: 23 903
Unique: 7571 (Rint = 0.041)
Corrections
Lorentz-polarization
Absorption
0.6526–1.0000
Trans. factors
© 2003 NRC Canada