Synthesis and structures of complexes with axially chiral isoquinolinyl-naphtholate ligands

Article abstract of DOI:10.1039/b907982c

The synthesis of axially chiral ligands 1-(3′,6′-di-t-butyl- 2′-hydroxy-1′-naphthyl)-3-R-isoquinoline (R = H, Prⁱ, Bu^t) (L^R-H) is described. Ligands with unsubstituted isoquinolinyl rings tend to give 1:2 metal complexes. The syntheses and crystal structures of Li₂(L^H)₂(THF)₂ (9), (L^H)₂Ti(OPrⁱ)₂ (12), Zn(L ^H)₂ (13) and [Mg(L^H)₂]₂ (14) are reported. Complex formation is highly stereoselective; the ligands in 1:2 complexes have the same stereochemistry (i.e. R,R and S,S but not R,S), whereas in the binuclear magnesium compound 14 the bridging and non-bridging ligands L^H have opposite stereochemistry. The reaction of L ^H-H with Pd(acac)₂ afforded the N,O chelate Pd(acac)(L^H) (10), whereas towards K₂PtCl₄ the same ligand acts as an N-donor only, to give trans-PtCl₂(L ^H-H)₂ (11) in which the OH groups are hydrogen-bonded to one of the two chloride ligands. The more bulky ligand with a t-butyl substituent in the 3-position of the isoquinolinyl ring reacts with zinc and magnesium bis(amides) to give the mixed-ligand species (L^Bu) ZnN(SiMe₃)₂ and (L^Bu)MgN(SiMe₃) ₂, respectively, which catalyse the ring-opening polymerisation of ε-caprolactone (CL) and rac-lactide (LA).

Full text of DOI:10.1039/b907982c

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PAPER
www.rsc.org/dalton | Dalton Transactions
Synthesis and structures of complexes with axially chiral
isoquinolinyl-naphtholate ligands†
Ruth H. Howard, Carlos Alonso-Moreno,‡ Lewis M. Broomfield, David L. Hughes, Joseph A. Wright and
Manfred Bochmann*
Received 21st April 2009, Accepted 20th July 2009
First published as an Advance Article on the web 27th August 2009
DOI: 10.1039/b907982c
The synthesis of axially chiral ligands 1-(3¢,6¢-di-t-butyl-2¢-hydroxy-1¢-naphthyl)-3-R-isoquinoline (R =
H, Pri, But) (LR-H) is described. Ligands with unsubstituted isoquinolinyl rings tend to give 1:2 metal
complexes. The syntheses and crystal structures of Li2(LH)2(THF)2 (9), (LH)2Ti(OPri)2 (12), Zn(LH)2
(13) and [Mg(LH)2]2 (14) are reported. Complex formation is highly stereoselective; the ligands in 1:2
complexes have the same stereochemistry (i.e. R,R and S,S but not R,S), whereas in the binuclear
magnesium compound 14 the bridging and non-bridging ligands LH have opposite stereochemistry. The
reaction of LH-H with Pd(acac)2 afforded the N,O chelate Pd(acac)(LH) (10), whereas towards K2PtCl4
the same ligand acts as an N-donor only, to give trans-PtCl2(LH-H)2 (11) in which the OH groups are
hydrogen-bonded to one of the two chloride ligands. The more bulky ligand with a t-butyl substituent
in the 3-position of the isoquinolinyl ring reacts with zinc and magnesium bis(amides) to give the
mixed-ligand species (LBu)ZnN(SiMe3)2 and (LBu)MgN(SiMe3)2, respectively, which catalyse the
ring-opening polymerisation of e-caprolactone (CL) and rac-lactide (LA).
Introduction
There has been significant interest in recent years in the controlled
polymerisation of cyclic esters to give biodegradable polymers.1
For the polymerisation of monomers like lactide, material proper-
ties depend crucially on adequate control of the stereochemistry.
Numerous ligand systems have been reported that result in good
control of polymer molecular weights and steric parameters,2-6
Chart 1
including many examples of chiral ligands.7 The vast majority of
these are built around the salicylaldiminato (“phenoxy-imine”)
motif.
of preventing the formation of coordination polymers. Steric
hindrance can be further increased by introducing R substituents
On the other hand, ligands with axial chirality have been used
successfully in a number of catalytic processes. For example BI-
in the 3-position on the isoquinolinyl ring. Such ligands are
NAP, BINAM and BINOL are the simplest, best-known examples
structurally related to the well-known phenoxyimine type ligands
with a wide range of applications.8-12 A potential variation on
=
B but without incorporating a reactive imine C N bond. We
these classic axially chiral ligands involves the replacement of one
therefore decided to explore the synthesis and coordination
naphthyl moiety with an isoquinoline unit.
chemistry of LR-H and its complexes with lithium, titanium,
The compound 1-(2¢-hydroxy-1¢-naphthyl)isoquinoline, A, was
first reported by Brown in 1993 as an intermediate in the synthesis
of a novel class of P–N chelating ligands (Chart 1).13 In that case
the hydroxy group was transformed into a -PPh2 substituent to give
a chiral phosphine ligand. For potential N–O chelating naphthol
ligands, it is advantageous to sterically protect the OH function by
a t-butyl substituent in the ortho position, as in LR-H, as a means
magnesium and zinc.
Results and discussion
Ligand synthesis and structure
The ligands LR-H were prepared as outlined in Scheme 1. 3,6-Di-
t-butylnaphthol (1) was prepared by treating a dichloromethane
solution of 2-naphthol with a catalytic amount of triflic acid and
an excess of isobutene. This reaction immediately yields a tri-
t-butylated product which degrades over 18 h to leave the di-
t-butylated naphthol derivative. The hydroxy group of 3,6-di-t-
butylnaphthol was then protected as a methyl ether 2 by methyl
iodide in the presence of potassium carbonate in DMF.14
Wolfson Materials and Catalysis Centre, School of Chemical Sciences and
Pharmacy, University of East Anglia, Norwich, NR4 7TJ
† Electronic supplementary information (ESI) available: Structure
diagrams of 1-bromo-2-methoxy-3,6-di-t-butylnaphthalene (3), and
[PdBr(PPh3)(m-isoquinolinyl)]2·CH2Cl2; NMR characterisation of 16;
polymer analysis data. CCDC reference numbers 728910–728919. For ESI
and crystallographic data in CIF or other electronic format see DOI:
10.1039/b907982c
‡ Present address: Departamento de Qu´ımica Inorga´nica, Orga´nica y
Bioqu´ımica, Universidad de Castilla-La Mancha, E-13071-Ciudad Real,
Spain.
The synthesis of the boronic acid 5 as a precursor for LR-H re-
quires the 1-bromo derivative 3.14 However, the reported synthesis
of 3 by bromination in acetic acid was rather unsatisfactory and
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Scheme 1
Scheme 2
furnished a mixture of 3 and the 8-bromo isomer 4 in a 1:3 ratio
(Scheme 2), from which 3 can be separated either by fractional
crystallisation from methanol or by flash chromatography in
about 25% yield.15 Replacing acetic acid by chloroform as solvent
increased the yield to 45%.14
However, following the method of Patwari et al.,16 bromination
with pyridinium bromochromate in acetic acid at 60 ◦C for 1
h provided a 98:2 mixture of the two isomers from which 3
could be isolated in 94% yield by flash chromatography. This
allowed the preparation of 3 on a 30 g scale as a white powder.
Slow evaporation of a light petroleum solution of 3 yielded
long colourless needles suitable for X-ray diffraction (see ESI†).
Reaction of 3 with n-butyl lithium followed by trimethylborate and
subsequent hydrolysis readily gave the boronic acid 5 in excellent
yields as a white solid.
Sterically more demanding ligands are accessible by introducing
substituents R in the 3-position of the isoquinoline ring. Thus
1-chloro-3-t-butyl-isoquinoline 7 was prepared by the reaction
sequence outlined in Scheme 3. Ortho-methylbenzoic acid was
converted to the N-methylamide via the acyl chloride and ring-
closed by double lithiation and RCN insertion to give the 3-
substituted isoquinolinone.17,18 In the final step, treatment of the
isoquinolinone with POCl3 gave 7 in 80% yield. A similar reaction
with PriCN in place of ButCN afforded the isopropyl derivative 8
in 55% yield.
Scheme 3
On the other hand, the coupling reaction of 5 with the 3-
isopropylchloroisoquinoline 8 gave typically yields of 6c of only
about 30% after work-up. Attempts were made to improve the
reaction by using alternative catalysts, for example the developed
complexes Fe(CpPR2)2PdCl2 (R = But, Pri). These catalysts have
been reported as highly effective in challenging cross-coupling
reactions.19 However, in our hands these catalysts produced rather
lower yields, with ~80% of 5 being hydrolysed to 2-methoxy-3,6-
1
di-t-butylnaphthalene (determined by H NMR). The low yields
prevented further investigations of the coordination chemistry of
LPr-H.
The ligands LH-H and LBu-H were recrystallised from Et2O at 5
◦C and the molecular structures determined by X-ray diffraction.
There are two independent molecules (X and Y) in crystals of
LH-H and these form R,R¢ and S,S¢ dimer pairs, each dimer pair
comprising one molecule of X and one of Y. One such pair, shown
in Fig. 1 (top), is joined through intermolecular hydrogen bonds,
Suzuki coupling of 5 with 1-chloroisoquinoline yielded 1-
(3,6-di-t-butyl-2-methoxy-1¢-naphthyl)isoquinoline 6a (R = H)
in 60% yield. Pd(PPh3)4 turned out to be the best catalyst, at
a level of 5 mol% in the presence of 3 equivalents of K2CO3
in a mixture of water, methanol and dimethoxyethane (1:2:5
v/v). Unfortunately, a twofold excess of 5 proved essential, as
a substantial portion of the boronic acid was hydrolysed to 2-
methoxy-3,6-di-t-butylnaphthalene during the coupling reaction.
The yield with respect to the isoquinoline was >90%. The coupling
reaction with the 3-t-butyl-chloroisoquinoline 7 proceeded in
analogous fashion to give 6b.
˚
˚
with OH ◊ ◊ ◊ N distances 1.78(6) A and 1.77(6) A and O–H ◊ ◊ ◊ N
angles of 177(3)◦ and 178(3)◦; the hydrogen atom was located in
the Fourier difference map and freely refined. There is significant
disorder in one t-butyl group of one of the ligands in the pair. The
angles between the planes of the isoquinolinyl and naphthyl rings
8668 | Dalton Trans., 2009, 8667–8682
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Fig. 1 Top: Molecular structure of (R)-LH-H showing the atomic numbering scheme. Hydrogen atoms have been omitted for clarity, except for the
hydroxyl protons. Thermal ellipsoids are drawn at the 30% (top) and 50% (bottom) probability level. Below: Views of the R (left) and S (right) enantiomers.
˚
Selected bond lengths (A): O(2a¢)–H(2a¢) 0.96(6); H(2a¢) ◊ ◊ ◊ N(12) 1.78(7).
in these R and S isomers are 92.8◦ and 105.5◦ respectively (Fig. 1
bottom).
and light petroleum at room temperature (Fig. 3); as well as the
two coordinated THF molecules, an additional non-coordinated
THF molecule was present in the asymmetric unit.
By contrast, LBu-H is monomeric, with an intramolecular
˚
OH ◊ ◊ ◊ N hydrogen bond of 1.90(2) A (Fig. 2).
The complex contains an Li2O2 core with a Li ◊ ◊ ◊ Li distance of
During the synthesis of LH-H, a by-product was isolated
during chromatography, which could be recrystallised from
dichloromethane as pale yellow blocks suitable for X-ray crys-
tallography. This compound was identified as [PdBr(PPh3)(m-
isoquinolinyl)]2 (see ESI†). Evidently the Br ligands indicate
the presence of bromide residues in 5. A number of related
Pd complexes with bridging pyridyl20 and isoquinolinyl groups
are known, e.g. [PdCl(PPh3)(m-isoquinolinyl)]2.13 This compound
constitutes the major proportion (ca. 80%) of the palladium
catalyst added and most likely constitutes a reservoir for re-entry
into the catalytic cycle.
2.525 A. The two lithium atoms exhibit similar distances to the
˚
anionic oxygen donors [Li(1)–O(1) 1.916(6); Li(1)–O(11) 1.909(6),
Li(2)–O(1) 1.877(6), Li(2)–O(11) 1.882(6)] despite the different
ligand environments about the two metal centres. As anticipated,
these Li–O interactions are shorter than those to the neutral THF
oxygen donors [Li(2)–O(21) 1.965(6), Li(2)–O(31) 1.993(7)]. The
two LH ligands in each dimer have identical stereochemistry.
Stirring a solution of LH-H in toluene with Pd(acac)2 at room
temperature for 12 h resulted in an orange suspension. Recrystalli-
sation of the crude product from CH2Cl2/light petroleum (9:1)
afforded Pd(acac)(LH) (10) as orange rods. The crystal structure
confirmed that the LH ligand is bonded as an N,O-chelate (Fig.
4). The palladium atom is almost coplanar with the four donors:
the deviation of the metal from the mean plane of the donor set is
Metal complexes
LH-H reacts rapidly with [LiN(SiMe3)2]2(THF)2 to give the
bimetallic oxygen-bridged lithium salt Li2(LH)2(THF)2 (9) in 58%
yield (Scheme 4).
Li2(LH)2(THF)2 forms a single stereoisomer, as shown by the
observation of only two t-butyl signals at d 1.43 and 1.39. Crystals
suitable for X-ray diffraction were grown from a mixture of THF
˚
only 0.033(3) A.
On the other hand, refluxing a mixture of K2PtCl4 and LH-H in a
mixture of toluene and glacial acetic acid gave colourless crystals
of PtCl2(LH-H)2 (11) in which the organic ligand is bound via
the isoquinoline-nitrogen atoms only (Fig. 5). The two protons
bound to oxygen atoms [H(1) and H(2)] were located in the
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Adding titanium(IV) isopropoxide to a diethyl ether solution of
LH-H in a molar ratio of 1:2 gave Ti(OPri)2(LH)2 (12) (Scheme 5)
which was isolated as yellow plate-like crystals from Et2O at 5 ◦C.
The molecular structure is shown in Fig. 6. The complex possesses
a distorted octahedral geometry. The two LH ligands have the same
stereochemistry (Fig. 6 shows the S isomer). The two isopropoxy
groups are mutually cis, as are the two isoquinolinyl nitrogen
atoms, leaving the aryloxides in trans positions. There are three
molecules of 12 in the asymmetric unit, but they differ little in
their geometric parameters. There are also 1.5 molecules of non-
coordinated ether per metal centre in the crystal structure which
are removed on drying in vacuo. The Ti–O bond lengths to the
OPri ligands are shorter than to naphtholate, an expression of the
stronger p-donor strength of OPri. The average angle between
the two isopropoxy ligands is wide, 104.01(17)◦, which causes
a distortion trans to them, where the average N–Ti–N angle is
only 75.57(10)◦. The naphthoxy Ti–O bonds are distorted away
from the isopropoxy ligands, such that the ONp–Ti–ONp bond angle
deviates by over 20◦ from linearity.
Treatment of Zn{N(SiMe3)2}2 with LH-H in dichloromethane
resulted in facile substitution of both amide ligands to give
Zn(LH)2 (13) (Scheme 5). Attempts to isolate the 1:1 complex
(LH)ZnN(SiMe3)2 were unsuccessful, and the 1:2 product was
formed irrespective of the stoichiometry. The zinc centre is in a
distorted tetrahedral environment, with bond angles varying from
92.54(6) to 122.74(6)◦ (Fig. 7). Both the ionic Zn–O bonds and
the dative Zn–N bonds are similar to typical literature examples.21
As was the case with 12, only one diastereomer is formed, as
evidenced by the presence of only one set of t-butyl signals in the 1H
NMR spectrum. The crystal structure confirmed that both ligands
in a complex have identical stereochemistry, i.e. either R,R or
S,S.
Fig. 2 Molecular structure of LBu-H. Hydrogen atoms except H(1) have
been omitted for clarity; thermal ellipsoids are drawn at the 50% proba-
◦
˚
bility level. Selected bond lengths (A) and angles ( ): N(1) ◊ ◊ ◊ H(1) 1.90(2);
O(1)–H(1) 0.839(17); O(1)–H(1) ◊ ◊ ◊ N(1) 154(3)◦; naphthyl–isoquinolinyl
torsion angle 62◦.
Fourier difference map, and show hydrogen-bonding to one of the
two chloride ligands. The complex crystallises with two toluene
molecules which are disordered about crystallographic inversion
centres. There is also a void in the structure, which is likely to
contain a highly disordered solvent molecule (the void contains
no significant electron density in the difference map).
The reactions of LH-H with Group 2, 4, 10 and 12 metal
compounds are summarised in Scheme 5.
Fig. 3 Molecular structure of Li2(LH)2(THF)2·THF (9) drawn at 30% probability. Hydrogen atoms and a non-coordinated molecule of THF have been
◦
˚
omitted for clarity. Selected bond lengths (A) and angles ( ): Li(1)–N(1) 2.015(6), Li(1)–N(11) 2.019(6); O(1)–Li(1)–O(11) 95.2(2), O(1)–Li(2)–O(11)
97.5(3), N(1)–Li(1)–N(11) 128.0(3), O(21)–Li(2)–O(31) 107.3(3); naphthyl–isoquinolinyl torsions angles are 68◦ [N(1)/O(1) ligand] and 62◦ [N(12)/O(11)
ligand], respectively.
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Scheme 4
Scheme 5
A similar reaction of LH-H with [Mg{N(SiMe3)2}2]2 in toluene
compound crystallises as a dimer, which was rather unexpected
gave [Mg(LH)2]2 (14). Unlike the analogous zinc complex, the 13
C
given the apparent steric bulk of the ligands and the almost
2+
identical ionic radii of Mg2+ (0.72 A) and Zn (0.74 A). The
1
˚
˚
and H NMR spectra of 14 showed the presence of two sets of
ligand environments, indicated by four different t-butyl resonances
at d 1.82, 1.74, 1.50 and 1.28. Recrystallisation of 14 from light
petroleum at room temperature produced large orange blocks,
suitable for an X-ray structure determination. The magnesium
structure is shown in Fig. 8.
The complex contains an Mg2O2 core. A twofold symmetry
axis relates the two halves of the dimer. Each magnesium atom
is 5-coordinate. The geometry is best described as trigonal-
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Fig. 4 Molecular structure of Pd(acac)(LH) (10). Ellipsoids are drawn at 50% probability. Hydrogen atoms have been omitted for clarity. Selected
◦
˚
bond lengths (A) and angles ( ): Pd(1)–O(1) 1.981(5), Pd(1)–O(21) 1.996(5), Pd(1)–O(22) 1.992(5), Pd(1)–N(1) 2.002(6), C(2)–O(1) 1.339(8), C(11)–N(1)
1.371(8); O(1)–Pd(1)–O(21) 87.0(2), O(1)–Pd(1)–O(22) 178.9(2), O(21)–Pd(1)–O(22) 94.1(2), O(1)–Pd(1)–N(1) 88.1(2); naphthyl–isoquinolinyl torsion
angle 49◦.
Fig. 5 Molecular structure of PtCl2(LH-H)2·2PhMe (11·2PhMe) showing 50% probability ellipsoids; t-butyl groups, hydrogen atoms (except those
◦
˚
bound to oxygen) and two molecules of toluene have been omitted for clarity. Selected bond lengths (A) and angles ( ): Pt(1)–N(1) 2.018(7),
Pt(1)–N(11) 2.027(7), Pt(1)–Cl(1) 2.290(2), Pt(1)–Cl(2) 2.310(2), O(1)–H(1) 0.83(2), O(11)–H(11) 0.86(2), H(1) ◊ ◊ ◊ Cl(2) 2.72(8), H(11) ◊ ◊ ◊ Cl(2) 2.73(6);
N(1)–Pt(1)–N(11) 173.9(3), N(1)–Pt(1)–Cl(1) 87.5(2), N(11)–Pt(1)–Cl(1) 88.4(2), N(1)–Pt(1)–Cl(2) 92.5(2), N(11)–Pt(1)–Cl(2) 91.7(2), Cl(1)–Pt(1)–Cl(2)
178.16(9); naphthyl–isoquinolinyl torsion angles are 88◦ [ligand N(1)/O(1)] and 80◦ [ligand N(11)/O(11)], respectively.
8672 | Dalton Trans., 2009, 8667–8682
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Fig. 6 Molecular structure of one of the three independent molecules of Ti(OPri)2(LH)2 (12) in the asymmetric unit. t-Butyl groups, hydrogen atoms
˚
and 1.5 molecules of Et2O have been omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level. Selected bond lengths (A) and
angles (◦):Ti(1)–O(1) 1.958(2), Ti(1)–O(11) 1.959(2), Ti(1)–O(21) 1.785(2), Ti(1)–O(31) 1.800(2), Ti(1)–N(1) 2.332(3), Ti(1)–N(11) 2.345(3), O(1)–C(2)
1.338(4), O(11)–C(102) 1.345(4); O(21)–Ti(1)–O(31) 103.77(11), O(1)–Ti(1)–O(11) 158.64(10), O(1)–Ti(1)–N(1) 79.53(9), O(11)–Ti(1)–N(11) 80.71(10),
N(1)–Ti(1)–N(11) 75.70(10); average naphthyl–isoquinolinyl torsion angle 61◦.
˚
˚
H (1.73 A and 1.20 A, respectively). The bridging and terminal
ligands have opposite senses of stereochemistry.
Treatment of LH-H with Ca{N(SiMe3)2}2(THF)2 in CH2Cl2 gave
a yellow solid. Extraction with light petroleum, concentration
and cooling to -25 ◦C yielded very small yellow crystals which
were unsuitable for X-ray crystallography. The elemental analysis
1
suggested the composition Ca(LH)2 (15). The H and 13C NMR
spectra showed the absence of THF ligands; the data were
incompatible with a dimeric structure analogous to the magnesium
complex; the observation of only one set of t-butyl signals for the
ligands suggests a monomeric structure as in the case of Zn(LH)2
(13).
In contrast to the results obtained with ligands containing
unsubstituted isoquinoline, the use of the 3-t-butylisoquinolinyl
ligand [LBu]- does produce mixed-ligand complexes of magnesium
and zinc. Thus the reaction of LBu-H with Zn{N(SiMe3)2}2
or [Mg{N(SiMe3)2}2]2 in toluene afforded the complexes
(LBu)Zn{N(SiMe3)2} (16) and (LBu)Mg{N(SiMe3)2} (17), respec-
tively, as yellow solids (Scheme 6).
Scheme 6
Although crystals of these complexes suitable for X-ray diffrac-
tion could not be obtained, the composition was confirmed by the
bipyramidal, with O(1) and N(11) in axial positions and O(11),
O(1)¢ and N(1) in the equatorial plane. The Mg–O bond lengths
fall in the usual range, and as expected the lengths of the terminal
Mg–O bonds are substantially shorter than the bridging Mg–O
elemental analyses and the 1H, 13C, { H} C, COSY and NOESY
NMR spectra. The appearance of isoquinolyl resonances at d 6.57
and 6.77 (Zn complex) and d 6.58 (Mg complex) is particularly
indicative of coordination: the free ligand contains no resonances
in this region (see ESI†). The trimethylsilylamide singlet is shifted
downfield compared to Zn{N(SiMe3)2}2.
1
13
bonds.22 The Mg ◊ ◊ ◊ Mg distance is 3.1668(15) A. There is a close
˚
contact between the metal and a hydrogen atom, Mg(1) ◊ ◊ ◊ H(31B)
˚
2.518 A; this is below the sum of the van der Waals radii of Mg and
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Fig. 7 Molecular structure of Zn(LH)2 (13) showing 50% probability ellipsoids. Hydrogen atoms have been omitted for clarity. Selected bond lengths
◦
˚
(A) and angles ( ): Zn–O(2) 1.9182(14), Zn–N(12) 2.0209 (17), Zn–O(32) 1.9114(14), Zn–N(42) 2.0286(18), O(2)–Zn–N(12) 92.54(6), O(2)–Zn–O(32)
122.74(6), O(2)–Zn–N(42) 115.82(7), O(32)–Zn–N(12) 114.75(7), N(12)–Zn–N(42) 120.02(7), O(32)–Zn–N(42) 93.40(6).
Fig. 8 Molecular structure of [Mg(LH)2]2 (14) showing 30% probability ellipsoids. Hydrogen atoms [except H(31b) and H(31b)¢] and two molecules
◦
˚
of isohexane have been omitted for clarity. Selected bond lengths (A) and angles ( ) with estimated standard deviations: Mg(1)–O(1) 2.0776(17),
Mg(1)–O(1)¢ 2.0291(16), Mg(1)–O(11) 1.9362(17), Mg(1)–N(1) 2.158(2), Mg(1)–N(11) 2.234(2), Mg(1) ◊ ◊ ◊ Mg(1)¢ 3.1668(15); O(1)–Mg(1)–O(11)
106.78(7), O(1)–Mg(1)–O(1)¢ 76.23(7), O(11)–Mg(1)–N(1) 111.63(8), O(1)–Mg(1)–N(1) 82.45(7), O(11)–Mg(1)–N(11) 87.55(7), O(1)–Mg(1)–N(11)
165.67(7), N(1)–Mg(1)–N(11) 92.73(8), C(2)–O(1)-Mg(1) 112.12(13); naphthyl–isoquinolinyl torsion angles are 59◦ [N(1)/O(1)] and 67◦ [N(11)/O(11)],
1
2
respectively. Symmetry operations to generate equivalent atoms: ¢ 1 - x, y, - z.
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Table 1 Ring-opening polymerisations with LH and LBu complexes
analysis showed that the molecular weight distribution was very
different and shows polymodal characteristics, whereas 16 shows
monomodal behaviour under comparable conditions.
Complex
Monomer
t/h
T/◦C
Conversion/%
The CL polymerisation with zinc complex 16 was studied in
more detail. The conversion increases linearly with time and slows
towards the end of a 24-h run. The polymer molecular weights
were analysed by NMR, MALDI-TOF mass spectrometry as
well as gel permeation chromatography (GPC) using polystyrene
standards, applying either polystyrene (PSt) or PCL Mark–
Houwink parameters (a = 0.700, log K = -3.854 and a = 0.740 and
log K = -3.564, respectively).23 The results were compared with
those obtained by triple detection methods using light scattering,
differential pressure and refractive index detectors (Table 2). The
results show that MALDI TOF-MS systematically underestimates
molecular weights. The triple detection method, while tending
to emphasize the higher molecular weight components, shows
12
16
16
17
12
14a
16
16
17
LA
LA
LA
LA
CL
CL
CL
CL
CL
24
10 min
1
1
130
130
60b
130
60a
50
none
100
2.5
21
5
40
100
59
39
4
16
2.5
14
1
60a
25c
25c
Conditions: [M]/[Cat] = 200, [Cat.] = 85 mmol;a 80 mm catalyst, THF
solvent, 50 ◦C; b 60 cm3 toluene; c 30 cm3 toluene.
Ring-opening polymerisations
¯
good overall agreement with the Mn values determined by NMR
The complexes Li2(LH)2(THF)2 (9), (LH)2Ti(OPri)2 (12),
Zn(LH)2 (13), [Mg(LH)2]2 (14), (LBu)ZnN(SiMe3)2 (16) and
(LBu)MgN(SiMe3)2 (17), were tested for activity in the ring-opening
polymerisation of e-caprolactone (CL) and rac-lactide (LA) (Table
1). The bis-ligand complexes of lithium (9), titanium (12), zinc
(13) and magnesium (14) proved essentially inactive towards rac-
lactide, and only 14 showed some activity for the polymerisation
of e-caprolactone (at 50 ◦C in THF or at 100 ◦C in toluene).
These complexes were not investigated further. The LBu metal
amido compounds 16 and 17, on the other hand, were active
as expected. The zinc complex 16 gave complete conversion of
neat LA in 10 min at 130 ◦C while the Mg analogue 17 generated
only 21% poly(lactide) (PLA) after 1 h under identical conditions.
In contrast, 17 was more active in the polymerisation of e-
methods. It is also apparent that the polydispersities broaden
with increasing reaction time, an indication that back-biting
and transesterification reactions are taking place at competitive
rates. This effect is reduced by carrying the reactions out at
higher dilution, which results in 100% conversion and narrower
polydispersity (entry 8). Much faster polymerisations leading to
much narrower molecular weight distributions are observed at 60
◦C (entry 9).
Conclusion
The palladium-catalysed coupling reaction of 3,6-di-t-butyl-2-
methoxynaphthalene-1-boronic acid with 3-substituted 1-chloro-
isoquinolines gives 1-(3¢,6¢-di-t-butyl-2¢-hydroxy-1¢-naphthyl)-3-
R-isoquinolines (R = H, Pri, But) in modest (R = Pri) to acceptable
(R = H, But) yields. The best catalyst for this reaction proved
to be Pd(PPh3)4 in the presence of potassium carbonate in a
1:2:5 water/methanol/dimethoxyethane mixture. Deprotection of
the coupled material gives the corresponding 2-naphthols. The
sterically less hindered ligand with an unsubstituted isoquinolinyl
ring (R = H) forms 1:2 N–O- chelate complexes ML2 which exist
as only one diastereomer, whereas in the binuclear magnesium
complex LMg(m-L)2MgL the terminal and the bridging ligands
have opposite chiralities. The torsion angles between the naphthyl
and the isoquinolinyl moieties in the complexes are much reduced
compared to the free ligand. In order to generate mixed-ligand
◦
caprolactone (39% conversion in 1 h at 25 C in 30 cm3 toluene
compared to 59% over 14 h for the zinc analogue under the same
conditions).
The poly(caprolactone) (PCL) produced by 16 and 17 was
generated by amide transfer to the first monomer, as shown by
the presence of a bis(trimethylsilyl)amino end group in the H
NMR spectra. The end group signal intensities were sufficiently
high to allow the determination of the number-average molecular
weights (Mn) by signal integration (see below). In order to
rule out the possibility that the observed activity might be
due to the disproportionation of 16 into Zn{N(SiMe3)2}2 and
Zn(LBu)2, the polymerisation of CL with Zn{N(SiMe3)2}2 was
tested. The bis(amido) complex is highly active; however, the GPC
1
¯
Table 2 e-Caprolactone polymerisation with complex 16a
¯
Mp
¯
¯
¯
¯
¯
¯
Entry
T/h
Conv./%
MALDI
Mn NMR
Mn PSt
Mn PCL
Mn Triple
Mw/Mn (Triple)
1
2
3
4
5
6
7
8
9
1
2
3
4
1.8
4.6
9.6
14
3550
5800
8348
6550
5950
1.4
2.1
2.2
2.4
2.7
4.3
5.4
3.1
1.8
6050
12250
15170
19050
19600
22600
36000
255900
155500
12250
16800
22600
24000
34500
53200
40350
86350
15300
20300
22250
30700
48350
74900
67550
109000
10500
14150
18500
18550
18900
n.d.
13700
19400
27650
45300
60850
49650
99000
6
19.9
59.9
74
14
24
17
2.5
100b
100c
n.d.
a Conditions: [CL]/[cat] = 200, toluene 20 cm3, 25 ◦C, [cat.] = 85 mmol. The molecular weights determined by MALDI-TOF are quoted as the peak
molecular weights. b In 50 cm3 toluene at 25 ◦C. c In 50 cm3 toluene at 60 ◦C.
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complexes of the type (LR)M-NR¢2 capable of reacting with cyclic
esters, the introduction of a t-butyl substituent in the 3-position
of the isoquinolinyl ring is required. The magnesium and zinc
complexes LBuM-N(SiMe3)2 catalyse the polymerisation of rac-
lactide and e-caprolactone with moderate activities and limited
polymer molecular weight control.
spectrometer. Samples for MALDI-TOF analysis were dissolved
in THF/CHCl3 1:1 (10 mg/cm3) and 10 mL was mixed with 30 mL
of a solution of 2-(4-hydroxyphenyl)azobenzoic acid (HABA, 0.1
M in THF/CHCl3, 1:1). Samples of standards were prepared in
the same way and suitable mixtures of different molecular weight
standards were used.
Preparation of 3-t-butyl-isoquinolinone
Experimental
The compound was made by a modification of a literature
procedure.18 n-Butyllithium (1.86 M in hexanes, 145 cm3, 270
mmol, was added to a solution of 2-methyl-N-methylbenzylamide
(15.90 g, 106 mmol) in THF (100 cm3) at 0 ◦C and stirred for 1 h.
A solution of Me3CCN (14.7 cm3, 130 mmol) in THF (50 cm3) was
added and the mixture warmed to room temperature. Saturated
ammonium chloride solution (75 cm3) was added and the organic
phase separated, washed with saturated sodium chloride solution
and water, dried over magnesium sulfate and the volatiles removed
in vacuo to give a clear yellow oil. The title compound was obtained
General procedures
Syntheses were performed under nitrogen using standard
Schlenk line techniques. Solvents were distilled from sodium–
benzophenone (diethyl ether, THF), sodium (toluene, ethyl
acetate), sodium–potassium alloy (light petroleum, b.p 40–60
◦C), or CaH2 (dichloromethane). Boron tribromide, 1,1,1,3,3,3-
hexamethyldisilazane, trifluoromethane sulfonic acid and
trifluoromethane sulfonic anhydride were distilled and stored
under argon prior to use. Trimethylborate was dried over sodium
for 24 h, distilled and stored over activated molecular sieves under
argon prior to use. N,N,N¢,N¢-Tetramethylethylenediamine was
dried over sodium at 130 ◦C for 72 h, distilled and stored over
activated molecular sieves prior to use. Ti(OPri)4 was distilled
under vacuum and kept over activated molecular sieves prior to
use. NMR solvents (CD2Cl2, C6D6) were dried over activated
◦
1
by recrystallisation from methanol at -25 C (17.10 g, 80%). H
NMR (300 MHz, 300 K, CDCl3): d 10.72 (br s, 1H, NH), 8.36
3
(d, 1H, J = 8.0 Hz, H8), 7.60 (m, 1H, H6), 7.57 (m, 1H, H5),
7.47 (m, 1H, H7), 6.36 (d, 1H, 3J = 1.9 Hz, H4), 1.41 (s, 9H, But);
13
=
C NMR (75 MHz CDCl3): d 164.7 (C O), 149.8, 138.8, 132.9,
127.6, 126.5, 126.3, 124.8, 101.1 (C–N), 34.9 (CMe3), 29.3 (CMe3).
˚
4 A molecular sieves and degassed by several freeze–thaw
cycles. e-Caprolactone was dried for a minimum of 24 h over
1-Chloro-3-t-butylisoquinoline (7)18
fresh calcium hydride, then distilled under vacuum and used
◦
immediately. rac-Lactide (LA) was recrystallised at -25 C from
A solution of 3-t-butyl-isoquinolinone (6.37 g, 31.7 mmol) in
phosphorus oxychloride (9 cm3, 95.3 mmol) was heated to reflux
for 4 h, cautiously added to ice and the resulting mixture
neutralised with sodium hydroxide solution (2 M). The organics
were extracted with diethyl ether (2 ¥ 200 cm3), dried over sodium
sulfate and the volatiles removed to give a dark brown oil. The
title product was obtained by vacuum distillation (87 ◦C, 0.1 mm
Hg) as a colourless, low-melting crystalline solid (5.59 g, 80%) 1H
NMR (300 MHz, 300 K, CDCl3): d 8.26 (d, 1H 3J = 8.4 Hz, H5),
7.75 (d, 1H, 3J = 8.1 Hz, H8), 7.67 (t, 1H, 3J = 6.8, 8.1 Hz, H7),
a saturated dr◦y ethyl acetate solution and then sublimed in
vacuo at 130 C before use. 1-Chloroisoquinoline,24 3,6-di-t-
butyl-2-naphthol 1,25 2-methoxy-3,6-di-t-butylnaphthalene 2,14
pyridinium bromochromate16,26 and the metal bis(silyl)amides
[LiN(SiMe3)2]2(THF)2, Zn{N(SiMe3)2}2, [Mg{N(SiMe3)2}2]2
and Ca{N(SiMe3)2}2(THF)2 were synthesised as previously
described.2a,27-29
NMR spectra were recorded using a Bruker DPX-300 spec-
trometer with a 5 mm BBO probe. Chemical shifts are reported
in ppm and referenced to residual solvent resonances (1H, 13C),
19F is relative to CFCl3. Nitrogen was purified by passing through
columns of supported P2O5, with moisture indicator, and activated
3
7.57 (t, 1H, J = 6.8, 8.4 Hz, H6), 7.50 (s, 1H, H4), 1.41 (s, 9H,
But); 13C NMR (75 MHz CDCl3): d 163 (C–Cl), 151 (C bridge),
139 (C bridge), 133 (C6), 131 (C5), 130 (C4), 127 (C7), 125 (C–N),
114.9 (C8), 37.5 (CMe3), 30.8 (CMe3).
˚
4 A molecular sieves. Elemental analyses were performed by
London Metropolitan University.
GPC analyses of polyesters were carried out in-house using a
Polymer Laboratories PL-GPC 220 instrument equipped with a
3-Isopropylisoquinolinone
˚
PLgel 5 A MIXED C column and a refractive index detector.
The compound was prepared by the modification of a literature
procedure.18 n-Butyllithium (1.8 M in hexanes, 40 cm3, 72.0 mmol)
was added to a solution of 2-methyl-N-methylbenzylamide (4.80
g, 32.2 mmol) in THF (100 cm3) ◦at 0 ◦C and stirred for 1 h. The
solution was then cooled to -50 C and 2,2-dimethylacetonitrile
(3.5 cm3, 38.6 mmol) in THF (50 cm3) was added and the mixture
was allowed to reach room temperature. Saturated ammonium
chloride solution (35 cm3) was added and the organic phase sepa-
rated, washed with saturated sodium chloride solution and water,
dried over magnesium sulfate and the volatiles removed in vacuo
and recrystallised in ethanol to give 3-isopropylisoquinolinone as
a white solid (3.32 g, 55%). 1H NMR (300 MHz, 300 K, CDCl3):
◦
The GPC column was eluted with THF at 40 C at 1 cm3 min-1
and was calibrated using 9 monodisperse polystyrene standards in
the range 580–1,000,000 Da. Remaining GPC measurements were
carried out by Dr. Steve Holding at RAPRA on a Viscotek TDA
Model 301 system, with refractive index, differential pressure and
light scattering detectors and equipped with a Polymer Laborato-
ries PL-GEL guard plus 2 ¥ mixed bed-B (30 cm ¥ 10 mm) columns.
The GPC column was eluted with THF (with antioxidant) at 30 ◦C
at 1 cm3 min-1 and a mathematical correction was applied to the
results using Mark–Houwink parameters for either polystyrene
(a = 0.700, log K = -3.854) or poly(caprolactone) (a = 0.740,
log K = -3.564). MALDI-TOF mass spectra were recorded
using a 96 well plate, on a Kratos Axima CFR MALDI-TOF
3
d 10.83 (br s, 1H, NH), 8.75 (d, 1H, J = 7.8 Hz, H8), 7.60 (m,
1H, H7), 7.47 (m, 1H, H5), 7.40 (m, 1H, H6), 6.31 (s, 1H, H4),
8676 | Dalton Trans., 2009, 8667–8682
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3
2.89 (sept, 1H, J = 6.9 Hz, CHMe2) 1.34 (s, 6H, CHMe2); 13C
under reduced pressure to give the title compound as a cream
1
NMR (75 MHz, 300 K, CDCl3): d 164.9 (C=O), 147.8, 139.1,
132.9, 127.7, 126.3, 126.1, 124.9, 101.1 (C–N), 32 (CHMe2).
solid (6.28 g, 99%). H NMR (300 MHz, 300 K, CDCl3): d 8.23
3
(d, 1H, J = 8.9 Hz, H8), 7.79 (s, 1H, H4), 7.71 (s, 1H, H5),
7.54 (d, 1H, 3J = 8.9 Hz, H7), 5.42 (s, 2H, B(OH)2), 3.95 (s, 3H,
OMe), 1.47 (s, 9H, 3-But), 1.41 (s, 9H, 6-But); 13C NMR (75 MHz,
300 K, CDCl3): d 163.9 (C-O), 147.1, 141.1, 133.9, 130.7, 128.9,
126.8, 124.7, 123.7, 63.2 (C–B), d 35.0 (CMe3), 34.6 (CMe3), 31.1
(CMe3), 29.7 (CMe3).
1-Chloro-3-isopropylisoquinoline (8)
The compound was prepared following a modified literature
procedure.27 A solution of 3-isopropylisoquinolinone (3.32 g,
17.17 mmol) in phosphorus oxychloride (10 cm3, 1.06 mol) was
heated to reflux for 48 h, cautiously added to ice and the resulting
mixture neutralised with sodium hydroxide solution (2 M). The
organics were extracted with diethyl ether (2 ¥ 200 cm3), dried over
sodium sulfate and the volatiles removed to give a dark orange oil.
The title product was obtained by vacuum distillation (87 ◦C, 0.1
mm Hg) as a colourless, low-melting crystalline solid (3.28 g, 93%)
1H NMR (300 MHz, 300 K, CDCl3): d 8.26 (d, 1H, 3J = 8.4 Hz,
H5), 7.76 (d, 1H, 3J = 8.1 Hz, H8), 7.67 (t, 1H, 3J = 6.5, 8.1 Hz,
H7), 7.58 (t, 1H, 3J = 6.8, 8.4 Hz, H5), 7.40 (s, 1H, H4), 3.15 (sept,
Preparation of 1-(3¢,6¢-di-t-butyl-2¢-methoxy-1¢-
naphthyl)isoquinoline (6a)
The synthesis is a modification of a literature procedure.30 1-
Chloroisoquinoline 0.99 g, 6.07 mmol) was added to a solu-
tion of Pd(PPh3)4 (0.35 g, 0.30 mmol) in thoroughly degassed
dimethoxyethane (DME) (25 cm3) and stirred for 30 min. 3,6-
Di-t-butyl-2-methoxy-1-naphthaleneboronic acid (5) (3.80 g, 12.1
mmol) in degassed methanol (10 cm3) and potassium carbonate
(1.68 g, 17.0 mmol) in degassed water (7 cm3) were added and the
mixture heated to reflux for 16 h. The mixture was then added
to water (100 cm3), extracted with Et2O (2 ¥ 100 cm3) and the
extracts dried over magnesium sulfate. The solvent was removed
under reduced pressure. The title compound was obtained by flash
column chromatography (SiO2, DCM, Rf = 0.6) to give an off-
white solid (1.44 g, 60%). 1H NMR (300 MHz, 300 K, CDCl3): d
8.76 (d, 1H, 3J = 5.6 Hz, HG), 7.91 (d, 1H, 3J = 7.6 Hz, HK), 7.89
(s, 1H, HE), 7.76 (s, 1H, HD), 7.74 (d, 1H, 3J = 5.9 Hz, HF), 7.66 (t,
1H, 3J = 6.9 Hz, HJ), 7.59 (d, 1H, 3J = 8.1 Hz, HH), 7.42 (t, 1H, 3J
= 7.1 Hz, HI), 7.31 (d, 1H, 3J = 8.9 Hz, HL), 7.07 (d, 1H, 3J = 8.8
1H, 3J = 6.9 Hz, CHMe2), 1.37 (d, 3J = 6.9 Hz, 6H, CHMe2). 13
C
NMR (75 MHz, 300 K, CDCl3): d 160.7 (C–Cl), 151.1 (C bridge),
139.0 (C bridge), 131.3 (C6), 127.9 (C5), 127.1 (C4), 126.7 (C7),
125.8 (C–N), 116.2 (C8), 36.1 (CHMe2), 22.9 (CHMe2).
Preparation of 1-bromo-2-methoxy-3,6-di-t-butylnaphthalene (3)
Pyridinium bromochromate (9.55 g, 37.0 mmol) and 2-methoxy-
3,6-di-t-butylnaphthalene 2 (9.99 g, 37.0 mmol) were dissolved
in acetic acid (100 cm3) and the solution heated to 65 ◦C for 2
h. The resulting green solution was added to water (150 cm3) and
extracted with ethyl acetate (2 ¥ 150 cm3). The organic portion was
washed with aqueous potassium hydroxide (5 M, 3 ¥ 200 cm3) and
dried over magnesium sulfate. The solvents were removed under
reduced pressure to yield a yellow solid (12.20 g, 95%). The title
compound was obtained as a white solid by flash chromatography
Hz, HM), 3.14 (s, 3H, HC), 1.52 (s, 9H, HB), 1.34 (s, 9H, HA). 13
C
NMR (75 MHz, 300 K, CDCl3): d 159.1, 157.7, 148.3, 143.4 (CG),
142.1, 137.3, 131.2, 130.8 (CJ), 130.3, 129.7, 128.7 (CH), 128.4 (CI),
127.7 (CK), 127.2 (CE), 126.9, 125.1 (CL), 124.8 (CM), 123.5 (CD),
120.4, 62.5 (CC), 36.2 (CMe3), 35.3 (CMe3), 32.8 (CMe3), 31.1
(CMe3).
1
(SiO2, light petroleum, Rf = 0.59) (11.4 g, 88%). H NMR (300
3
MHz, 300 K, CDCl3): d 8.14 (d, 1H, J = 8.9 Hz, H8), 7.72 (s,
1H, H4), 7.70 (s, 1H, H5), 7.61 (d, 1H, 3J = 8.9 Hz, H7), 4.03 (s,
3H, OMe), 1.49 (s, 9H, 3-But), 1.41 (s, 9H, 6-But). 13C NMR (75
MHz, 300 K, CDCl3): d 156.2, 148.7, 144.3, 131.2, 130.7, 126.3,
126.2, 126.0, 123.5, 116.6, 62.3 (OMe), 36.1 (CMe3), 35.1 (CMe3),
31.6 (CMe3), 31.3 (CMe3).
Preparation of 1-(3¢,6¢-di-t-butyl-2¢-methoxy-1¢-
naphthyl)-3-t-butylisoquinoline (6b)
1-Chloro-3-t-butyl-isoquinoline (0.64 g, 2.90 mmol) was added
to a solution of Pd(PPh3)4 (0.17 g, 0.15 mmol) in DME (25
cm3) and stirred for 30 min. To this were added 5 (1.85 g, 5.90
mmol) in methanol (10 cm3) and potassium carbonate (1.40 g,
14.0 mmol) and the mixture heated to reflux for 16 h. The mixture
was then added to water (100 cm3) and extracted with diethyl
ether (2 ¥ 100 cm3), dried over magnesium sulfate, filtered and the
solvent removed under reduced pressure. The title compound was
obtained by flash column chromatography (SiO2, 5% ethyl acetate
in light petroleum, Rf = 0.6) to give an off-white solid (1.28 g,
In this and other bromination methods, 8-bromo-2-methoxy-
3,6-di-t-butylnaphthalene 4 may be obtained as a by-product
which can be separated by flash chromatography (SiO2, light
1
petroleum, Rf = 0.75). H NMR (300 MHz, 300 K, CDCl3): d
7.77 (s, 1H, H4), 7.66 (s, 2H, HJ, H1), 7.41 (s, 1H, H5), 4.00 (s, 3H
OMe), 1.47 (s, 9H, 3-But), 1.39 (s, 9H, 6-But).
Preparation of 3,6-di-t-butyl-2-methoxy-1-naphthaleneboronic
1
97%). H NMR (300 MHz, 300 K, CDCl3): d 7.94 (s, 1H, HD),
acid (5)
7.89 (d, 1H, 3J = 8.1 Hz, HG), 7.84 (s, 1H, HE), 7.74 (s, 1H, HL),
7.63 (t, 1H, 3J = 7.7 Hz, HI), 7.49 (d, 1H, 3J = 8.2 Hz, HK), 7.35
(m, 2H, HJ, HH), 7.23 (d, 1H, 3J = 8.9 Hz, HF), 3.26 (s, 3H, OMe),
1.59 (s, 9H, But), 1.57 (s, 9H, But), 1.42 (s, 9H, But). 13C NMR (75
MHz, 300 K, CDCl3): d 161.8, 159.6, 157.4, 144.9, 139.6 137.5,
136.2, 134.4, 129.6 (CI), 127.5 (CK), 127.4 (CG), 126.9 (CJ), 126.3
(CD), 125.9 (CH), 125.7 (CF), 123.5 (CE), 123.3, 113.2, 102.4 (CL),
54.6 (CC), 37.4 (CMe3), 35.1 (CMe3), 34.7 (CMe3), 31.3 (CMe3),
30.3 (CMe3), 29.9 (3¢-CMe3) (atom numbering as given for 6a).
n-Butyllithium (1.8 M in hexanes, 11.1 cm3, 20.0 mmol) was added
to a solution of 1-bromo-2-methoxy-3,6-di-t-butylnaphthalene
(7.00 g, 20.0 mmol) in THF (70 cm3) at -78 ◦C and stirred for
30 min. Trimethylborate (11.4 cm3, 100 mmol) was added and
the mixture warmed to room temperature over 2 h. The solvents
were removed under reduced pressure and the residues dissolved in
diethyl ether, quenched with water and the organic portion dried
over magnesium sulfate. Subsequently the volatiles were removed
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Preparation of 1-(3¢,6¢-di-t-butyl-2¢-methoxy-1¢-naphthyl)-
3-isopropylisoquinoline (6c)
1,1¢-(3,6-Di-t-butyl-2-hydroxynaphthyl)-3-isopropylisoquinoline
(LPr-H)
The title compound was made as described for 6a as a white solid
via flash column chromatography (SiO2, 5% ethyl acetate in light
petroleum) (0.80 g, 29%). 1H NMR (300 MHz, 300 K, CDCl3): d
7.89 (s, 1H, HD), 7.85 (d, 1H, 3J = 7.2 Hz, HG), 7.74 (s, 1H, HE),
7.67 (d, 1H, 3J = 8.1 Hz, HI), 7.59 (s, 1H, HL), 7.49 (d, 1H, 3J =
This compound was synthesised from 6c as described for LH-H
using column chromatography (SiO2, CH2Cl2) as a yellow solid in
60% yield. 1H NMR (300 MHz, 300 K, CDCl3): d 9.75 (br s, 1H,
OH), 7.87 (s, 1H, HD), 7.84 (d, 1H, 3J = 6.1 Hz, HG), 7.76 (s, 1H,
HE), 7.64 (t, 1H, 3J = 7.4 Hz, HI), 7.58 (s, 1H, HL), 7.33-7.22 (m,
3H, HJ, HH, HK), 7.10 (d, 1H, 3J = 8.2 Hz, HF), 3.32 (sept, 1H, 3J
= 6.3 Hz, CHMe2), 1.58 (s, 9H, 6-But), 1.49 (d, 3H, 3J = 5.5 Hz,
CHMe2), 1.45 (d, 3H, 3J = 5.5 Hz, CHMe2), 1.34 (s, 9H, 3-But).
13C NMR (75 MHz, 300 K, CDCl3): d 159.8, 157.9, 153.9, 146.0,
139.5, 137.0, 138.6, 130.8, 129.6, 129 (CK), 128.4 (CG), 127.6 (CJ),
127.2 (CD), 126.3 (CH), 125 (CF), 124.6 (CE), 117.1 (CL), 116.2,
36.1 (CMe3), 35.9 (CN), 34.9 (CMe3), 31.7 (6-CMe3), 31 (3-CMe3),
30.3 (Pri) (atom numbering as given for 6a).
3
7.63 Hz, HK), 7.36-7.31 (m, 2H, HJ, HH), 7.13 (d, 1H, J = 9.10
Hz, HF), 3.36 (sept, 1H, 3J = 6.7 Hz, CHMe2) 3.21 (s, 3H, OMe),
1.53 (s, 9H, 6-But), 1.47 (d, 3H, 3J = 3.2 Hz, CHMe2), 1.45 (d, 3H,
3J = 2.9 Hz, CHMe2), 1.37 (s, 9H, 3-But). 13C NMR (75 MHz, 300
K, CDCl3): d 161.1, 160.1, 158.5, 145.8, 142.2, 138.2, 131.3, 130.7,
130.2 (CI), 128.5 (CK), 127.8 (CG), 127.0 (CJ), 126.7 (CD), 125.6
(CH), 125.2 (CF), 123.8 (CE), 115.9, 62.1 (CC), 36.5 (CMe3), 35.3
(6-CMe3), 32.1 (6-CMe3), 31.8 (3-CMe3), 23.2 (CHMe2) (atom
numbering as given for 6a).
Preparation of [Li2(LH)2(THF)2 (9)
Preparation of 1-(3¢,6¢-di-t-butyl-2¢-hydroxy-1¢-
A solution of LH-H (0.23 g, 0.60 mmol) in dichloromethane (35
cm3) was added slowly via a narrow cannula to a solution of
[LiN(SiMe3)2]2(THF)2 (0.29 g, 0.60 mmol) in dichloromethane at
room temperature. The mixture was then stirred for a period of 12
h, the solvent removed and product extracted with THF (3 cm3).
Recrystallisation from THF/petroleum (1/4) (10 cm3) gave the
9·THF as fine yellow needles suitable for X-ray crystallography
(0.34 g, 62%). Anal. Calcd. for C62H72N2O4Li2: C, 80.67, H, 7.86;
naphthyl)isoquinoline (LH-H)
Boron tribromide (0.67 cm3, 7.04 mmol) was added to a solution
of 6a (2.33 g, 5.86 mmol) in CH2Cl2 (40 cm3) under argon and
stirred for 12 h. The solution was added to water (20 cm3),
the organic layer separated and washed with saturated sodium
hydrogen carbonate (30 cm3), dried over magnesium sulfate and
the solvents removed under reduced pressure. The title product
was obtained via column chromatography (SiO2, CH2Cl2) as a
yellow solid (1.57 g, 70%). 1H NMR (300 MHz, 300 K, CDCl3): d
9.00 (br s, 1H, OH), 8.55 (s, 1H, 3J = 5.7 Hz, HF), 7.90 (d, 1H, 3J
= 8.2 Hz, HJ), 7.83 (s, 1H, HD), 7.73 (s, 1H, HC), 7.71 (m, 1H, HE),
7.67 (d, 1H, 3J = 7.9 Hz, HI), 7.60 (d, 1H,3J = 8.5 Hz, HG), 7.39 (t,
1H, 3J = 7.6 Hz, HH), 7.21 (d, 1H, 3J = 8.2 Hz, HK), 6.92 (d, 1H,3J
= 8.8 Hz, HL), 1.50 (s, 9H, 3-But), 1.36 (s, 9H, 6-But). 13C NMR
(75 MHz, 300 K, CDCl3): d 158.6, 153.2, 146.1, 141.9 (CF), 139.6,
137.5, 131.1 (CG), 130.2, 128.9, 128.7, 128.6 (CI), 127.7 (CH), 127.6
(CD), 127.4 (CJ), 124.9 (CK), 124.6 (CL), 123.6 (CE), 121.1, 117.6
(C–OH), 35.9 (CMe3), 34.9 (CMe3), 31.7 (6-CMe3), 30.2 (3-CMe3)
(atom numbering as given for 6a).
1
N, 3.03. Found: C, 80.0; H, 7.71; N, 2.70. H NMR (300 MHz,
300 K, CD2Cl2): d 7.88–7.68 (m, 12H, aryl), 7.61 (d, 2H, 3J = 8.2,
3
3
aryl), 7.36 (d, 2H, J = 6.2 Hz, aryl), 6.44 (d, 2H, J = 8.9 Hz,
3
aryl), 6.99 (d, 2H, J = 9.7 Hz, aryl), 3.40 (br s, 8H, THF), 1.57
(br s, 8H, THF,), 1.43 (s, 18H, But), 1.39 (s, 18H, But). 13C NMR
(75 MHz, 300 K, CD2Cl2): 141.0–122.7 (Carom), 68.2 (THF), 35.8,
34.5 (CMe3), 31.5 (CMe3), 30.0 (THF), 25.6 (CMe3).
Preparation of Pd(acac)(LH) (10)
A solution of LH-H (0.10 g, 0.26 mmol) in toluene (20 cm3) was
added to a suspension of Pd(acac)2 (0.08 g, 0.26 mmol) in toluene
(10 cm3). After stirring at reflux for 12 h, the resulting orange
suspension was filtered. The solvent was then removed and the
sticky orange solid obtained was recrystallised in CH2Cl2/light
petroleum (9/1) at room temperature for 5 d; yielding orange rods
of 10 suitable for X-ray crystallography (0.08 g, 54%). Anal. Calcd.
for C32H35NO3Pd·1.5CH2Cl2: C, 57.55; H, 4.83; N, 1.92. Found:
C, 57.23; H, 5.68; N, 1.72. 1H NMR (300 MHz, 300 K, CD2Cl2):
d 8.48 (d, 1H, 3J = 6.6 Hz, aryl), 7.95 (d, 1H, 3J = 8.2 Hz, aryl),
1,1¢-(3,6-Di-t-butyl-2-hydroxynaphthyl)-3-t-butylisoquinoline
(LBu-H)
Boron tribromide (1.1 cm3, 1.00 mmol) was added to a solution of
6b (2.50 g, 5.52 mmol) in CH2Cl2 (40 cm3) under argon and stirred
for 2 h. The solution was added to water (20 cm3), the organic layer
separated and washed with saturated sodium hydrogen carbonate
(30 cm3), dried over magnesium sulfate and the solvents removed
3
7.74 (m, 4H, aryl), 7.57 (d, 1H, J = 8.8 Hz, aryl), 7.35 (m, 1H,
1
3
under reduced pressure to give a yellow solid (2.35 g, 97%). H
aryl), 7.11 (m, 1H, aryl), 6.75 (d, 1H, J = 8.8 Hz, aryl), 5.44
(s, 1H, CH(acac)), 2.03 (s, 3H, Me(acac)), 1.56 (s, 9H, But), 2.01
(s, 3H, Me(acac)), 1.38 (s, 9H, But). 13C NMR (75 MHz, 300 K,
CD2Cl2): d 187.4, 186.6 (O–C(acac)), 168.0, 156.9, 144.8, 143.9,
141.3, 137.0, 131.8, 131.7, 128.7, 128.0, 127.0, 126.5, 124.1, 123.8,
123.2, 120.9 (Carom), 101.2 (CH(acac)), 36.0, 34.7 (CMe3), 31.4,
30.1 (CMe3), 25.7, 26.1 (Me(acac)).
NMR (300 MHz, 300 K, CDCl3): d 10.25 (br s, 1H, OH), 7.87 (d,
1H, 3J = 6.2 Hz, HH), 7.85 (s, 1H, HD), 7.76 (s, 1H, HL), 7.70 (s,
1H, HE), 7.63 (t, 1H, 3J = 7.5 Hz, HJ), 6.59 (d, 1H, 3J = 8.5 Hz,
HK), 7.29 (t, 1H, 3J = 7.7 Hz, HI), 7.24 (d, 1H, 3J = 8.9 Hz, HG),
3
7.10 (d, 1H, J = 8.9 Hz, HF), 1.59 (s, 9H, 3¢-But), 1.53 (s, 9H,
3-But), 1.38 (9H, s, 6-But); 13C NMR (75 MHz, 300 K, CDCl3):
d 161.7, 157.6, 154.3, 145.9, 139.6, 138.5, 130.7 (CJ), 129.9, 129.0
(CK), 128.4, 127.7 (CD), 127.6 (CH), 126.7, 126.5 (CI), 125.1 (CF),
124.7 (CG), 123.7 (CL), 116.8 (C–OH), 114.9 (CE), 37.5 (CMe3),
35.9 (CMe3), 34.9 (CMe3), 31.7 (6-CMe3), 30.7 (3-CMe3), 30.2
(3¢-CMe3) (atom numbering as given for 6a).
Preparation of PtCl2(j1-LH-H)2 (11)
A mixture of K2PtCl4 (0.11 g, 0.27 mmol) and LH-H (0.21
g, 0.54 mmol) was refluxed in toluene with glacial acetic acid
8678 | Dalton Trans., 2009, 8667–8682
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(10 cm3) for 48 h. After cooling the resulting suspension was
collected via filtration, washed with acetic acid and water and
dried under vacuum to afford a yellow solid. The product was
recrystallised from toluene at room temperature overnight yielding
white crystals of 11·2toluene suitable for X-ray crystallography.
(0.16 g, 63%). Anal. Calcd. for C68H74Cl2N2O2: C, 67.09; H, 6.13;
N, 2.30. Found: C, 66.85; H, 5.90; N, 2.12. 1H NMR (300 MHz,
300 K, CDCl3): d 8.48 (d, 2H, 3J = 7.4 Hz, aryl) 8.21–8.07 (m, 4H,
H, 6.91, N, 3.61. 1H NMR (300 MHz, 300 K, C6D6): d 8.32
3
3
(d, 2H, J = 6.1 Hz, aryl), 8.25 (m, 2H, aryl), 8.00 (d, 2H, J
3
= 9.2 Hz, aryl), 7.97 (m, 2H, aryl), 7.65 (d, 2H, J = 8.8 Hz,
3
aryl), 7.56 (m, 2H, aryl), 7.44 (m, 2H, aryl), 7.39 (d, 2H, J =
7.0 Hz, aryl), 7.32-7.20 (m, 10H, aryl), 7.06–7.04 (m, 4H, aryl.),
3
6.92 (d, 2H, J = 5.7 Hz, aryl), 6.85 (m, 2H, aryl), 6.61 (m, 2H,
3
3
aryl), 6.33 (d, 2H, J = 5.3 Hz, aryl), 5.92 (d, 2H, J = 8.7 Hz,
aryl), 1.82 (s, 18H, But), 1.74 (s, 18H, But), 1.50 (s, 18H, But),
1.28 (s, 18H, But). 13C NMR (75 MHz, 300 K, C6D6): d 168.2–
111.6 (76C, Carom) 36.3, 36.0, 34.7, 34.3 (CMe3), 32.8, 31.8, 31.7,
30.7 (CMe3).
3
3
aryl), 7.34 (d, 2H, J = 6.3 Hz, aryl), 7.21–7.04 (d, 8H, J = 9.0
Hz, aryl), 6.56–6.48 (m, 4H, aryl), 1.98 (s, 18H, But), 1.30 (s, 18H,
But).
Preparation of Ti(OPri)2(LH)2 (12)
Preparation of Ca(LH)2 (15)
Titanium tetrakis(isopropoxide) (0.16 cm3, 0.54 mmol) was added
to a solution of LH-H (0.21 g, 0.54 mmol) in Et2O (30 cm3). The
mixture was stirred for 3 h. The solvents were removed under
reduced pressure and the resulting yellow solid washed with light
petroleum (15 cm3). The precipitate was dried in vacuo for 4 h to
give 12 (0.40 g, 80%). Anal. Calcd. for C60H70N2O4Ti: C 77.40,
H 7.58, N 3.01; Found: C 77.28, H 7.65, N 2.93. Crystals of
12·1.5Et2O suitable for X-ray analysis were obtained from an
A solution of LH-H (0.30 g, 0.78 mmol) in CH2Cl2 (20 cm3)
was added to a solution of Ca{N(SiMe3)2}2(THF)2 (0.19 g, 0.39
mmol) in CH2Cl2 (20 cm3). The mixture was left to stir overnight.
Removal of the volatiles gave a yellow solid. Extraction with light
petroleum (40 cm3), concentration to 20 cm3 and cooling to -25
◦C yielded very small yellow crystals (0.22 g, 72%). Anal. Calcd.
for C54H56N2O2Ca: C, 80.56; H, 7.01; N, 3.48. Found: C, 80.67;
H, 7.08; N, 3.33. X-Ray quality crystals could not be obtained.
1H NMR (300 MHz, 300 K, CD2Cl2): d 7.43–7.87 (m, 10H,
aryl), 7.42 (m, 2H, aryl), 7.01 (m, 2H, aryl), 6.90 (d, 2H, 3J
◦
1
Et2O solution at -25 C. H NMR (300 MHz, 300 K, C6D6):
3
d 8.64 (d, 2H, J = 6.4 Hz, aryl), 8.19 (s, 2H, aryl), 7.94 (s, 2H,
3
3
3
aryl), 7.83 (d, 2H, J = 8.6 Hz, aryl), 7.08 (d, 2H, J = 8.9 Hz,
= 6.0 Hz, aryl), 6.74 (d, 2H, J = 9.1 Hz, aryl), 5.77 (d, 2H,
3
3J = 5.9 Hz, aryl), 1.58 (s, 18H, But), 1.34 (s, 18H, But); 13C
NMR (300 MHz, 300 K, CD2Cl2): d 163.1, 161.7, 144.1, 143.3,
140.9, 137.3, 132.0, 130.1, 128.9, 127. 127.3, 123.7, 123.5, 123.2,
118.6, 118.3 (Caroms), 34.7 (CMe3), 34.5 (CMe3), 31.7 (CMe3),
31.4 (CMe3).
aryl), 6.99 (m, 4H, aryl), 6.84 (d, 2H, J = 8.0 Hz, aryl), 6.74
3
3
(m, 2H, aryl), 6.02 (d, 2H, J = 6.4 Hz, aryl), 4.14 (sept, 2H, J
= 11.6 Hz, Pri), 2.03 (s, 18H, But), 1.32 (s, 18H, But), 0.81 (d,
12H, J = 11.6 Hz, Pri). 13C NMR (75 MHz, 300 K, CDCl3): d
3
157.8, 148.5 (C–O), 145.3, 141.9, 137.9, 136.6, 135.7, 130.1, 129.7,
129.1, 127.9, 125.2, 125.1, 122.9, 120.3, 115.1, 106.0, 33.5 (CMe3),
31.5 (CMe3), 27.9 (CHMe2), 23.5 (CMe3), 17.2 (CMe3), 13.7
(CHMe2).
Preparation of (LBu)ZnN(SiMe3)2 (16)
Zinc bis[bis(trimethylsilyl)amide] (0.28 cm3, 0.70 mmol) was added
to a solution of LBu-H (0.31 g, 0.70 mmol) in toluene (10 cm3),
giving an immediate deep orange colour. The mixture was stirred
for 16 h. Removal of the volatiles in vacuo gave an orange solid
(0.44 g, 95%). Anal. Calcd. for C37H54N2OSi2Zn: C 66.89; H 8.19;
N 4.22; Found: C 66.85, H 8.10, N 4.26; 1H NMR (300 MHz, 300
K, C6D6): d 8.10 (s, 1H, HD), 7.83 (d, 1H, 3J = 1.9 Hz, HL), 7.48
Preparation of Zn(LH)2, (13)
To a solution of LH-H (0.31 g, 0.78 mmol) in dichloromethane (30
cm3) was added Zn{N(SiMe3)2}2 (0.15 g, 0.39 mmol). The resulting
orange solution was left to stir for 3 h. Concentration and cooling
to 5 ◦C yielded yellow plate-shaped crystals suitable for X-ray
crystallography. (0.24 g, 74%). Anal. Calcd. for C54H56N2O2Zn:
C, 78.10; H, 6.80; N, 3.37. Found: C, 77.98; H, 6.73; N, 3.30. 1H
NMR (300 MHz, 300 K, CD2Cl2): d 7.97–7.56 (m, 16H, aryl),
3
3
(d, 1H J = 8.6 Hz, HH), 7.31 (s, 1H, HE), 7.24 (t, 1H, J = 7.1
Hz, HJ), 7.08 (m, 2H, HF, HG), 6.77 (d, 1H, 3J = 8.8 Hz, HK), 7.59
3
(t, 1H, J = 7.4 Hz, HI), 1.92 (s, 9H, 6-But), 1.39 (s, 9H, 3-But),
3
7.04 (m, 2H, aryl), 6.55 (d, 2H, J = 9.0 Hz, aryl), 1.64 (s, 18H,
1.30 (s, 9H, 3¢-But), 0.19 (s, 18H, SiMe3); 13C NMR (75 MHz,
300 K, CDCl3): d 157.8, 148.5 (C–O), 145.3, 141.9, 137.9, 136.6,
135.7, 130.1, 129.7, 129.1, 127.9, 125.2, 125.1, 122.9, 120.3, 115.1,
106.0, 33.5 (CMe3), 31.5 (CMe3), 29.5 (CMe3), 23.5 (CMe3), 21.2
(CMe3), 17.2 (CMe3), 7.2 (SiMe3) (atom numbering as given for
6a).
But), 1.38 (s, 18H, But). 13C NMR (75 MHz, 300 K, CD2Cl2): d
166.7, 144.0, 143.8, 139.7, 138.3, 132.0, 130.8, 129.2, 129.0, 128.6,
128.6, 127.3, 126.3, 124.0, 123.8, 123.7, 120.7, 34.6, 34.3 (CMe3),
31.5, 30.5 (CMe3).
Preparation of [Mg(l-LH)(LH)]2 (14)
Preparation of (LBu)MgN(SiMe3)2 (17)
A solution of LH-H (0.20 g, 0.52 mmol) in toluene (50 cm3) was
added to a solution of [Mg{N(SiMe3)2}2]2 (0.09 g, 0.13 mmol)
at room temperature and the solution left to stir for a period
of 2 h. Removal of the volatiles gave a yellow solid. Extraction
with light petroleum (20 cm3) and recrystallisation for 2 d at
room temperature yielded yellow/orange blocks of 14·hexane
suitable for X-ray crystallography (0.07 g, 39%). Anal. Calcd. for
C108H112N4O4Mg2: C, 82.17; H, 7.15; N, 3.55. Found: C, 81.70,
A solution of magnesium bis[bis(trimethylsilyl)amide] (0.28 g, 0.70
mmol) in toluene (10 cm3) was added to a solution of LBu-H (0.30
g, 0.70 mmol) in toluene (10 cm3). The deep orange mixture was
stirred for 16 h. Removal of the volatiles in vacuo gave an orange
solid (0.41 g, 98%). Anal. Calcd. for C37H54ON2Si2Mg: C 74.66, H
9.14, N 4.14; Found: C 74.78, H 9.10, N 4.14. 1H NMR (300 MHz,
300 K, C6D6): d 8.12 (m, 1H, HD), 7.98 (m, 1H, HL), 7.86 (m, 2H,
This journal is
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Dalton Trans., 2009, 8667–8682 | 8679
©

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Table 3 Crystal and refinement data of LH-H, LBu-H and compounds 9–10
Compound
LH-H
L
Bu-H
9·THF
10
Empirical formula
Formula weight
Temperature/K
Crystal colour, shape
Crystal size/mm
Crystal system
C27H29NO
383.50
295(1)
C31H37NO
439.62
140(2)
C66H80Li2N2O5·C4H8O
C32H35NO3Pd
588.01
140(2)
995.20
120(2)
Pale yellow needle
0.85 ¥ 0.10 ¥ 0.04
Monoclinic
P21/n
16.228(3)
11.794(2)
25.429(5)
90
105.175(15)
90
4697.1(14)
8
1.085
1648
3.5 to 20.0
0.065
None applied
29 252
Light yellow rod
0.40 ¥ 0.04 ¥ 0.04
Monoclinic
C2/c
25.055(4)
12.368(2)
17.991(4)
90
113.732(13)
90
5103.6(16)
8
1.144
1904
3.71 to 27.50
0.068
0.997 and 0.766
32 009
Yellow plate
0.18 ¥ 0.16 ¥ 0.06
Monoclinic
P21/n
16.524(6)
10.431(4)
37.439(13)
90
Orange rod
0.40 ¥ 0.06 ¥ 0.02
Monoclinic
P21/c
11.2647(13)
26.934(3)
11.8122(14)
90
112.275(11)
90
3316.4(7)
4
1.178
1216
3.68 to 27.50
0.587
0.988 and 0.568
35 477
Space group
˚
a/A
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
94.995(4)
90
6429(4)
3
˚
V/A
Z
4
D
calcd/g cm-3
1.028
2144
4.60 to 28.38
0.063
0.996 and 0.518
31 739
F(000)
q range/◦
Absorption coefficient/mm-1
Max. and min. transmission
No. of reflections collected
No. of unique reflections, Rint
No. of ‘observed’ reflections [I >
2s(I)]
4361, 0.146
2295
5836, 0.194
2253
11 067, 0.080
5747
7552, 0.211
3004
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices R1, wR2 [I >
2s(I)]
Final R indices R1, wR2 (all data)
Largest diff. peak and hole/e A
4361/0/544
1.017
0.075, 0.071
5836/1/310
0.916
0.080, 0.088
11 065/8/716
0.935
0.077, 0.197
7552/464/355
0.930
0.083, 0.154
0.174, 0.091
0.17 and -0.13
0.236, 0.120
0.20 and -0.18
0.135, 0.226
0.34 and -0.29
0.225, 0.188
0.68 and -0.81
-3
˚
HH, HE), 7.53 (s, 1H, HJ), 7.21 (m, 1H, HF), 6.58 (m, 3H, HG, HK,
HI), 1.39 (s, 9H, 6-But), 1.33 (s, 9H, 3-But), 1.28 (s, 9H, 3-But), 0.09
(s, 18H, N(SiMe3)2); 13C NMR (75 MHz, 300 K, CDCl3): d 161.8,
150.3 (C–O), 147.3,144.9, 140.9, 138.6, 137.9, 133.1, 131.7, 130.1,
129.3, 127.2, 126.7, 123.9, 122.3, 121.1, 110.0, 37.5 (CMe3), 35.5
(CMe3), 29.5 (CMe3), 23.5 (CMe3), 22.2 (CMe3), 21.2 (CMe3), 8.0
(SiMe3).
Structures were determined by direct methods using SHELXS
(LH-H and 12)34 or SIR92 (LBu-H, 9, 10, 11 and 14);35 compound
13 was solved by the Patterson routines in SHELXS. In all
cases refinement was carried out by full-matrix least-squares
methods using SHELXL-9734 within the WinGX suite.36 Non-
hydrogen atoms (except those in minor components of disordered
t-butyl groups in LH-H) were refined with anisotropic thermal
parameters. Hydrogen atoms, with the exception of those bound
to oxygen were included using a riding model; hydrogen atoms
bound to oxygen were located in the Fourier difference map
and refined freely. In compounds 9, 10 and 14, disordered
solvent regions were handled using the PLATON SQUEEZE
procedure.37 Crystal and refinement data are collected in Tables 3
and 4.
X-Ray crystallography
In all cases except for LH-H, crystals were suspended in per-
fluorinated polyether oil, mounted on glass fibres and trans-
ferred directly to the cold N2 stream of the diffractometer; the
crystal of LH-H was fixed with epoxy resin for room temper-
ature measurements. Data for compounds 11, 12 and 14 were
collected on a Bruker-Nonius KappaCCD diffractometer, and
for compounds LH-H, LBu-H, 10 and 13 were collected on an
Oxford Diffraction Xcalibur diffractometer with Sapphire-3 CCD
detector; both diffractometers were equipped with molybdenum
Acknowledgements
This work was supported by the Engineering and Physical
Sciences Research Council. We thank Johnson Matthey for gifts
of Fe(CpPR2)2PdCl2 (R = But, Pri). C. A.-M. thanks the Junta
de Comunidades de Castilla-La Mancha and the Fondo Social
Europeo (Grant No. 05/24) for financial support. We thank
Dr Steve Holding (RAPRA Ltd) for GPC analyses and triple-
detector results. We thank the EPSRC National Crystallography
Service for data collection for compounds 11, 12 and 14, and
Professor W. Clegg for collecting synchrotron diffraction data for
compound 9.
˚
targets [l(Mo Ka) = 0.71069 A]. Data for compound 9 were
collected on a Bruker SMART APEX2 CCD diffractometer at
Daresbury SRS station 16.2smx with radiation of wavelength
˚
0.7977 A. Data collection and processing were carried out
using APEX2 and SAINT,31 DENZO and SCALEPACK (9,
11, 12 and 14),32 or CrysAlis CCD and RED (the remaining
compounds).33
8680 | Dalton Trans., 2009, 8667–8682
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The Royal Society of Chemistry 2009
©

View Article Online
Table 4 Crystal and refinement data of compounds 11–14
Compound
11·2PhMe
12·1.5Et2O
13·2CH2Cl2
14·2hexane
Empirical formula
Formula weight
Temperature/K
Crystal colour, shape
Crystal size/mm
Crystal system
C54H58Cl2N2O2Pt·2(C7H8)
2(C60H70N2O4Ti), 3(C4H10O)
2084.52
120(2)
C54H56N2O2Zn·2(CH2Cl2)
C108H112Mg2N4O4·2(C6H14)
1217.28
1000.20
1750.98
120(2)
140(1)
140(2)
Colourless lath
0.26 ¥ 0.08 ¥ 0.06
Triclinic
¯
P1
11.3200(4)
14.8220(6)
19.2990(7)
84.676(2)
77.397(2)
74.396(2)
3041.6(2)
2
Yellow lath
Yellow plate
0.59 ¥ 0.52 ¥ 0.15
Monoclinic
P21/n
11.3702(7)
22.8448(8)
19.5818(10)
90
101.385(5)
90
4986.3(4)
4
Yellow block
0.30 ¥ 0.20 ¥ 0.16
Monoclinic
C2/c
29.690(2)
17.4249(15)
22.9030(18)
90
109.804(7)
90
11 148.0(15)
4
0.36 ¥ 0.06 ¥ 0.02
Triclinic
¯
P1
Space group
˚
a/A
13.7337(4)
16.2802(5)
42.8450(14)
96.227(1)
91.659(1)
107.015(1)
9089.6(5)
3
1.142
3366
2.91 to 27.48
0.191
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
3
˚
V/A
Z
D
calcd/g cm-3
1.329
1248
2.91 to 27.48
2.439
1.332
2096
3.5 to 27.5
0.751
1.043
3776
3.54 to 27.50
0.072
F(000)
q range/◦
Absorption
coefficient/mm-1
Max. and min.
transmission
0.868 and 0.581
0.9962 and 0.9345
1.121 and 0.900
0.989 and 0.828
No. of reflections collected
No. of unique reflections,
Rint
42 554
13 692, 0.073
146 935
40 617, 0.1083
60 843
11 364, 0.041
64 046
12 817, 0.0907
No. of ‘observed’
reflections [I > 2s(I)]
10 404
23 409
7776
5533
Data/restraints/parameters 13692/163/715
40 617/285/2135
1.029
0.094, 0.168
11 364/0/586
1.059
0.043, 0.110
12 817/40/600
0.839
0.060, 0.140
Goodness-of-fit on F2
Final R indices R1, wR2 [I
> 2s(I)]
1.131
0.086, 0.158
Final R indices R1, wR2
(all data)
0.123, 0.178
0.168, 0.202
0.071, 0.117
0.151, 0.161
Largest diff. peak and
hole/e A
2.60 and -0.91
0.82 and -0.63
1.06 and -0.74
0.35 and -0.34
-3
˚
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