The β-dialdiminato ligand [{N(C6H3Pr i2-2,6)C(H)}2CPh]-: The conjugate acid and Li, Al, Ga and in derivatives

Article abstract of DOI:10.1039/b607782j

The synthesis of the following crystalline complexes is described: [Li(L)(thf)₂] (2), [Li(L)(tmeda)] (3), [MCl₂(L)] [M = Al (4), Ga (5)], [In(Cl)(L)(-Cl)₂Li(OEt₂)₂] (6), [In(Cl)(L){N(H)C₆H₃Prⁱ₂-2,6}] (7), [In(L){N(H)C₆H₃Prⁱ₂-2,6} ₂] (8), [{In(Cl)(L)(-OH)}₂] (10), [L(Cl)In-In(Cl)(L)] (11) (the thf-solvate 11a, the solvate-free 11b and the hexane-solvate 11c), [{In(Cl)L}₂(-S)] (12) and [InCl₂(L)(tmeda)] (13) ([L] ^- = [{N(C₆H₃Prⁱ ₂-2,6)C(H)}₂CPh]^-). From H(L) (1), via Li(L) in Et₂O, and thf, tmeda, AlCl₃, GaCl₃ or InCl₃ there was obtained 2, 3, 4, 5 or 6, respectively in excellent yield. Compound 6 was the precursor for each of 7-11, 13 and [{InCl ₃(tmeda)₂{-(OSnMe₂)₂}}] (14) by treatment with one (7) or two (8) equivalents of K[N(H)(C₆H ₃Prⁱ₂-2,6)], successively Li[N(SiMe ₃)(C₆H₃Prⁱ₂-2,6)] and moist air (10), Na in thf (11a), tmeda (13), or successively tmeda and Me ₃SnSnMe₃ (14). Crystals of 11b (with an equivalent of In) and 11c were obtained from InCl or thermolysis of [In(Cl)(L){N(SiMe ₃)(C₆H₃Prⁱ₂-2,6)}] (9) {prepared in situ from 6 and Li[N(SiMe₃)(C₆H ₃Prⁱ₂-2,6)] in Et₂O}, respectively. Compound 12 was obtained from a thf solution of 11a and sulfur. X-Ray data for crystalline 1-6, 8, 11a, 11b, 11c, 12 and 14 are presented. The M(L) moiety in each (not the L-free 14) has the monoanionic L ligated to the metal in the N,N′-chelating mode. The MN1C1C2C3N2 six-membered M(L) ring is π-delocalised and has the half-chair (2, 3 and 11) or boat (4-8, 10 and 13) conformation. The Royal Society of Chemistry 2006.

Full text of DOI:10.1039/b607782j

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/dalton | Dalton Transactions
The b-dialdiminato ligand [{N(C6H3Pri2-2,6)C(H)}2CPh]−: the conjugate
acid and Li, Al, Ga and In derivatives†
Yanxiang Cheng, David J. Doyle, Peter B. Hitchcock and Michael F. Lappert*
Received 1st June 2006, Accepted 18th July 2006
First published as an Advance Article on the web 3rd August 2006
DOI: 10.1039/b607782j
The synthesis of the following crystalline complexes is described: [Li(L)(thf)2] (2), [Li(L)(tmeda)] (3),
[MCl2(L)] [M = Al (4), Ga (5)], [In(Cl)(L)(l-Cl)2Li(OEt2)2] (6), [In(Cl)(L){N(H)C6H3Pri2-2,6}] (7),
[In(L){N(H)C6H3Pri2-2,6}2] (8), [{In(Cl)(L)(l-OH)}2] (10), [L(Cl)In–In(Cl)(L)] (11) (the thf-solvate
11a, the solvate-free 11b and the hexane-solvate 11c), [{In(Cl)L}2(l-S)] (12) and [InCl2(L)(tmeda)] (13)
([L]− = [{N(C6H3Pri2-2,6)C(H)}2CPh]−). From H(L) (1), via Li(L) in Et2O and thf, tmeda, AlCl3, GaCl3
or InCl3 there was obtained 2, 3, 4, 5 or 6, respectively in excellent yield. Compound 6 was the precursor
for each of 7–11, 13 and [{InCl3(tmeda)2{l-(OSnMe2)2}}] (14) by treatment with one (7) or two (8)
equivalents of K[N(H)(C6H3Pri2-2,6)], successively Li[N(SiMe3)(C6H3Pri2-2,6)] and moist air (10), Na in
thf (11a), tmeda (13), or successively tmeda and Me3SnSnMe3 (14). Crystals of 11b (with an equivalent
of In) and 11c were obtained from InCl or thermolysis of [In(Cl)(L){N(SiMe3)(C6H3Pri2-2,6)}] (9)
{prepared in situ from 6 and Li[N(SiMe3)(C6H3Pri2-2,6)] in Et2O}, respectively. Compound 12 was
obtained from a thf solution of 11a and sulfur. X-Ray data for crystalline 1–6, 8, 11a, 11b, 11c, 12 and
14 are presented. The M(L) moiety in each (not the L-free 14) has the monoanionic L ligated to the
metal in the N,Nꢀ-chelating mode. The MN1C1C2C3N2 six-membered M(L) ring is p-delocalised and
has the half-chair (2, 3 and 11) or boat (4–8, 10 and 13) conformation.
Some earlier studies had shown that b-diketiminato ligands were
Introduction
not invariably innocent spectators. Thus, there are examples that
a b-methyl group in I (as in L1–L5) may be prone to deprotonation
b-Diketiminates are widely used as spectator ligands; they are
shown in I in their monoanionic N,Nꢀ-chelating, p-delocalised
form. They bind strongly to metals, are readily tuneable (by
means of changing the substituents R1, R2, R3 in I) to provide
a range of steric and electronic demands on the metal, and have
a variety of ligand-to-metal binding modes. The ligands I are
able to stabilise compounds not only in a low state of molecular
aggregation, but also in a low metal oxidation state, as cations, and
complexes containing metal-multiply-bonded-co-ligands. Many
b-diketiminatometal complexes have a useful role as catalysts or
biomolecular mimics. The topic has been reviewed.1 Our studies
in this field, initially with R1 = SiMe3, R2 = Ph and R3 = H, date
back to 1994,2 and our most recent publication is in ref. 3.
(e.g., ref. 4); while a c-H in H(L1) was capable of undergoing a
1,3-prototropic shift, as in H(L1) + PCl(Ph)X → II (X = Cl5a or
Ph5b).These factors prompted us to focus on the b-dialdiminato
ligand L (i.e., I with R1 = C6H3Pri2-2,6, R2 = H and R3
=
Ph). It was first used by Tolman et al., in the context of b-
dialdiminatocopper(I)/O2 reactivity, in order to provide less steric
hindrance at the metal than its L1 analogue.6 It has recently been
shown that crystalline [Tl(L)]7 and [Tl{(N(SiMe3)C(Ph)2CH)}],7
like [Tl(L1)]8 are monomers.
The majority of b-diketiminato ligands which have featured in
the literature have been nitrogen analogues of acac−: i.e., I with
R2 = Me and R3 = H, such as L1 to L5 with R1 = C6H3Pri2-2,6
(L1), C6H4Me-4 (L2), Me (L3), Et (L4) or Pri (L5).
Results and discussion
The results and discussion is divided into three parts. The first deals
with the structures of the crystalline b-dialdimine H[{N(C6H3Pri2-
2,6)C(H)}2CPh] (1) [≡ H(L)], two of its lithium derivatives
[Li(L)(thf)2] (2) or [Li(L)(tmeda)] (3), and the synthesis and struc-
tures of the dichloro(b-dialdiminato)metallanes [MCl2(L)] [M =
Al (4) or Ga (5)]. The second is concerned with the synthesis and
structure of the heterobimetallic (InIII/Li) compound [In(Cl)(L)(l-
Cl)2Li(OEt2)2] (6) and six of its reactions leading to a range of b-
dialdiminatoindium compounds: the InIII complexes 7–10, 12 and
The Chemistry Department, University of Sussex, Brighton, UK BN1 9QJ.
E-mail: m.f.lappert@sussex.ac.uk; Fax: 44 1273 677196; Tel: 44 1273
678316
† Electronic supplementary information (ESI) available: Details of struc-
tural data for 11b and 11c and the molecular structures of 3 and 4. See
DOI: 10.1039/b607782j
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 4449–4460 | 4449
©

View Article Online
13 and the binuclear InII compound 11, as well as the L-free InIII
complex 14. The final section describes the conformation of the
M(L) fragment in nine of the crystalline complexes: 2–6, 8 and
10–12.
The crystalline compounds [H(L)] (1), [Li(L)(thf)2] (2),
[Li(L)(tmeda)] (3) and [MCl2(L)] [M = Al (4), Ga (5)]
The b-dialdimine
1 was prepared by basic hydrolysis of
the vinamidium pentafluorophosphate III,9 yielding the b-
=
dialdehyde PhC(H)(CH O)2, and treatment of the latter with 2,6-
diisopropylaniline.6
Fig. 1 The molecular structure of 1 (30% probability ellipsoids).
Yellow, X-ray quality crystals of 1 were grown from hot diethyl
ether. Its molecular structure is shown in Fig. 1 and selected
geometrical parameters are listed in Table 1. The molecule lies
on a two-fold axis with the NH-hydrogen atom disordered over
two positions. While therefore the core NCCCN framework in 1
is p-delocalised, this is not the case for the crystalline b-diketimine
H[{N(C6H3Pri2-2,6)C(Me)}2CH] since the pairs of N–C and C–
The yellow crystalline lithium b-dialdiminates 2 and 3 were
obtained from a solution of Li(L)6 and the appropriate neutral
co-ligand, eqn (1). Likewise, Li(L) was the precursor for the Al (4)
and Ga (5) dichloro(b-dialdiminate)s, eqn (2).
C bond lengths in the equally planar NCCCN core are unequal:
10
˚
˚
1.313(4) or 1.358(4) A and 1.434(4) and 1.362(4) A, respectively.
The delocalisation in 1 does not extend to the c-Ph group or
the N-aryl groups, the dihedral angle between the C3-to-C4ꢀ and
the C1C2C1ꢀ planes or the C7-to-C12 and the NC1C2 planes
being 37.7 or 84.8◦, respectively. The ipso-carbon atom of the c-
Ph group of 1 is coplanar with the NCCCN framework, and the
ipso-carbon atoms of the aryl substituents at the nitrogen atoms
(1)
˚
are only 0.026 A out of that plane.
◦
a
˚
Table 1 Selected bond lengths (A) and angles ( ) for 1
(2)
N–C1
N–C7
C1–C2
C2–C3
1.314(2)
1.430(2)
1.402(2)
1.485(3)
C1–N–C7
N–C1–C2
C1–C2–C1ꢀ
N–C7–C12
N–C7–C8
122.18(15)
124.41(16)
120.9(2)
119.56(17)
118.56(16)
The molecular structure of 2 is illustrated in Fig. 2 (for 3, see
ESI†) and selected structural parameters for 2 and 3, together with
comparative data for [Li{(N(C6H3Pri2-2,6)C(Me))2CH}(OEt2)2]
(IV),10 are in Table 2.
Compounds 4 and 5 were characterised not only by their X-
ray molecular structures but also by satisfactory C, H and N
a Symmetry transformations to generate equivalents atoms: ꢀ −x + 1/2, −y
+ 1/2, z.
◦
i
10
˚
Table 2 Selected bond lengths (A) and angles ( ) for 2, 3 and [Li{(N(C6H3Pr 2-2,6)C(Me))2CH}(OEt2)2] (IV)
2
3
IV10
2
3
IV10
Li–N1
Li–N2
N1–C1
N2–C3
N1–C10
N2–C22
1.995(3)
1.986(4)
1.307(2)
1.308(2)
1.431(2)
1.425(2)
2.067(3)
2.005(3)
1.314(2)
1.311(2)
1.429(2)
1.432(2)
1.912(4)
1.917(4)
1.324(3)
1.325(3)
1.402(3)
1.402(3)
C1–C2
C2–C3
C2–C4
Li–O1
Li–O2
Li–N3
Li–N4
1.419(3)
1.410(3)
1.481(3)
1.920(4)
2.003(4)
1.408(2)
1.410(2)
1.482(2)
1.402(3)
1.402(3)
1.911(4)
1.911(4)
2.125(3)
2.240(3)
N1–Li–N2
Li–N1–C1
Li–N2–C3
C1–C2–C3
94.76(15)
114.52(15)
115.15(16)
123.02(7)
94.72(12)
115.85(13)
117.37(13)
124.53(14)
99.9(2)
120.9(2)
122.0(2)
129.5(2)
N1–C1–C2
N2–C3–C2
C1–C2–C4
C3–C2–C4
128.02(17)
126.66(17)
116.83(16)
120.02(17)
128.53(14)
127.85(14)
118.18(18)
116.94(13)
124.3(2)
123.2(2)
4450 | Dalton Trans., 2006, 4449–4460
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
significantly p-delocalised, since each of the N1–C1/N2–C3 and
the C1–C2/C2–C3 pairs are essentially identical and intermediate
between being single and double. The conformation of this core
and its substituents at N1, N2 and C2 is considered later, together
with corresponding data for 2, 3 and In derivatives.
Several b-diketiminatoaluminium dichlorides and their gallium
analogues have been reported, including [MCl2{(N(R)(Me))2CH}]
{M = Al and R = C6H4Me-4,11a C6H3Pri2-2,6 (Va),11b Me,11c Et,11c
Pri;11c and M = Ga with R = C6H3Pri2-2,6 (Vb)11b}. The structural
data for Va and Vb are similar to those for 4 and 5, respectively,
e.g., the endocyclic Al–N, N–C and C–C bond lengths for Va are
˚
1.884(2), 1.345(4) and 1.400(5) A, respectively, and the N1–Al–
N2, Al–N–C, N–C–C and C–C–C bond angles are 99.4(1), 119.7,
121.8(10) and 127.7(1)◦, respectively.11b
Synthesis, structures and reactions of selected
b-dialdiminatoindium compounds and of an L-free InIII complex
Fig. 2 The molecular structure of 2 (30% probability ellipsoids).
A series of new, yellow [except for the colourless compound 10] b-
dialdiminatoindium(III) compounds 6–10, 12 and 13, as well as the
yellow dinuclear [L(Cl)InII–InII(Cl)L] (11) and the colourless L-
free complex 14, have been prepared as shown in Scheme 1. Apart
from 7, 9 and 11, each was obtained in X-ray-quality crystalline
form and was structurally characterised. Except for 9 (which was
only obtained in situ), 10 (isolated in small yield) and the L-free
14, each gave satisfactory microanalytical (C, H, N) and NMR
spectral solution data. Aside from 9, each of 6–13 showed a parent
ion or near daughter fragment in its EI-mass spectrum.
microanalyses and 1H, 13C and 27Al (for 4) NMR spectra in C6D6.
The EI-mass spectrum of 4 showed an intense parent molecular
ion. Crystalline 4 and 5 are isomorphous. Hence the molecular
structure of just one of them (5) is shown in Fig. 3 (that of
4 is in the ESI†). Selected geometric parameters for both are
listed in Table 3. The bonds within the N1C1C2C3N2 core are
Treatment of indium(III) chloride with Li(L), prepared in situ
from the b-dialdimine H(L) (1) and LiBun, gave (i in Scheme 1)
the key heterobimetallic (In/Li) complex 6 in high yield. Complex
6 was the precursor to each of the complexes 7–11, 13 and 14
and indirectly (via 11) to 12. Thus, 6 with the appropriate alkali
metal amide gave 7, 8 or 9 (ii, iii or iv, respectively in Scheme 1);
and 9 in moist air afforded (v in Scheme 1) 10. Reduction of 6,
using sodium, gave (vi in Scheme 1), 11 in reasonable yield as the
1:1 thf adduct 11a. Solvent-free crystals 11b were isolated (vii in
Scheme 1) in low yield by thermal In–N homolysis of 9, while
the hexane-solvate crystals 11c were obtained (viii in Scheme 1)
in good yield, together with metallic indium, from indium(I)
chloride and Na(L). Oxidation of 11 with sulfur furnished (ix in
Scheme 1) the bis[indium(III)] sulfide 12. Chloride bridge-splitting
of 6 by tmeda afforded (x in Scheme 1) the mononuclear In(III)
dichloride 13. Attempted reduction of 6 by hexamethylditin failed,
Fig. 3 The molecular structure of 5 (50% probability ellipsoids).
◦
˚
Table 3 Selected bond lengths (A) and angles ( ) for 4 and 5
4 M = Al
5 M = Ga
4 M = Al
5 M = Ga
M–N1
M–N2
N1–C1
N2–C3
N1–C10
N2–C22
1.8808(14)
1.8801(13)
1.329(2)
1.330(2)
1.4597(19)
1.4579(19)
1.924(2)
1.923(2)
1.327(3)
1.325(3)
1.455(3)
1.458(3)
C1–C2
C2–C3
M–Cl1
M–Cl2
C2–C4
1.398(2)
1.395(2)
2.1195(6)
2.1143(7)
1.488(2)
1.396(4)
1.399(4)
2.1644(8)
2.1544(7)
1.492(4)
N1–M–N2
M–N1–C1
M–N2–C3
C1–C2–C3
M–N1–C10
96.91(6)
97.26(9)
120.48(17)
119.75(17)
123.1(2)
N1–C1–C2
N2–C3–C2
N1–M–Cl1
N1–M–Cl2
126.03(15)
127.28(14)
112.37(5)
112.16(5)
126.8(2)
127.9(2)
112.28(7)
112.14(7)
121.59(10)
120.64(10)
122.07(14)
122.41(10)
121.18(16)
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 4449–4460 | 4451
©

View Article Online
2
Scheme 1 Preparation of the b-dialdiminatoindium compounds 6–13 [L = g -{N(C6H3Pri2-2,6)C(H)}2CPh] and the InCl3 complex 14. Reagents and
conditions: i, Li(L), Et2O, 25 ◦C; ii, K[N(H)(C6H3Pri2-2,6)], Et2O, 25 ◦C; iii, 2 K[N(H)(C6H3Pri2-2,6)], Et2O, 25 ◦C; iv, Li[N(SiMe3)(C6H3Pri2-2,6)], Et2O,
25 ◦C; v, moist air; vi, Na, Et2O, then thf; vii, PhMe, 100 ◦C; viii, Na(L), thf, then InCl, 25 ◦C; x, tmeda, Et2O; xi, tmeda, Et2O, then (SnMe3)2, thf, 50 ◦C.
the isolated very low yield product was the cyclodistannoxane-
bridged bis[trichloroindium(III)] complex 14 (xi in Scheme 1).
Although the mechanism of its formation remains obscure, its
structure may be of some interest.
It is noteworthy that compound 6 has an InIII(l-Cl)2Li core, a
structural feature, which is very rare in b-diketiminatometal(III)
chemistry. There are only few X-ray-characterised b-diketiminato
complexes having an MIII(l-Cl)2Li core, mainly with a less bulky
substituents on the nitrogen atoms.12 Furthermore, as evident
from Scheme 1, 6 is a valuable substrate for a range of b-
dialdiminatoindium compounds.
The indium(III) amides 7, 8 and 9 and the bridged sulfide 12 are
of interest since, we believe, there are no b-diketiminatoindium
amides or a sulfide in the literature. However, each of the (l-
OH)2-bridged di[indium(III)] compound 10 and the di[indium(II)]
complex 11 has a single precedent. Thus, Stender and Power
showed that treatment of indium(I) chloride with Li(L1) gave
not only indium metal but also the crystalline compounds
[L1(Cl)In–In(Cl)L1] (16%) and [{In(Cl)(L1)(l-OH)}2] (15%) [L1 =
{N(C6H3Pri2-2,6)C(Me)}2CH].13 The latter was presumably (like
10) formed by inadvertent hydrolysis. This L1 reaction parallels
that of viii in Scheme 1, in which the formation of 11b and indium
metal, each in good yield, supports the view that the course of
the reaction may have followed the pathway shown in Scheme 2.
The preparation of 11, as the crystalline 11b (vi in Scheme 1)
by reduction of [InCl2(L)(tmeda)] (13) with metallic sodium,
contrasts with the report that In(L1)X2 (X = Cl or I) with Na or K
gave indium metal and H(L1).13 There is circumstantial support for
the notionthat In(L)was anintermediate, since HillandHitchcock
have shown that the crystalline indium(I) b-diketiminate In(L1)
was obtained from InI, K[N(SiMe3)2] and H(L1).8 Using this
procedure, but with less sterically hindered b-diketiminato ligands
[L6]− and [L7]− Hill et al. obtained the X-ray-characterised
compounds
[(L6)InIn(L6)]
and
[{(L7)(I)In}2{(l-L7)In}4]
[L6
=
{N(C6H2Me3–2,4,6)C(Me)}2CH, L7
= {N(C6H3Me2-
3,5)C(Me)2}CH].14
Although a bis[b-diketiminatoindium(III)] sulfide is presently
unknown, an oxygen analogue [{In(Cl)(L2)}2(l-O)] is well
documented, [L2 = {N(C6H4Me-4)C(Me)}2CH].15 Several b-
diketiminatoindium(III) halides, related to 13, are known, includ-
ing [InCl2(L1)],11b [InI2(L1)],11b and [InI2(L2)].15 Whereas cyclodis-
tannoxanes are rare and require sterically demanding substituents
at the tin(IV) atoms, as in [Sn{CH(SiMe3)2}(l-O)]2,16 there are
examples of complexes in which a much less bulky analogue acts
as an O,Oꢀ-bridging ligand, as in [{SnBut2(Cl)2}2{l-(SnMe2(lꢀ-
O))2}]17a and [{SnCl2(Me)2}2{l-(SnMe2(lꢀ-O))2}].17b
Selected molecular structural data for compounds 6, 8, 10, 11a,
12 and 14 are shown in Tables 4–9, respectively, with ORTEP
representations shown in the corresponding Fig. 4–9. Such data
on 11b and 11c, solvates of 11, are provided in the ESI.† As for
compounds 2–5, conformational aspects of the In(L) fragment of
each of 6, 8, 10, 11a and 12 are summarised in Table 10 and are
discussed in the next section of the “results and discussion” portion
of this paper, together with a consideration of the geometric
parameters for the In(L) moieties.
Scheme 2 Proposed reaction pathway for reaction viii of Scheme 1.
4452 | Dalton Trans., 2006, 4449–4460
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
◦
◦
a
˚
˚
Table 7 Selected bond lengths (A) and angles ( ) for 11a
Table 4 Selected bond lengths (A) and angles ( ) for 6
In–N1
In–N2
2.187(2)
2.218(2)
1.330(3)
1.314(3)
1.438(3)
1.436(3)
1.390(4)
1.408(4)
C2–C4
In–Cl1
In–Cl2
In–Cl3
Li–Cl1
Li–Cl3
Li–O1
Li–O2
1.501(3)
2.4481(7)
2.3782(7)
2.4982(8)
2.385(5)
2.361(5)
1.928(5)
1.931(5)
In–N1
In–N2
N1–C1
N2–C3
N1–C10
N2–C22
2.164(2)
2.159(2)
1.321(4)
1.320(3)
1.450(3)
1.444(3)
C1–C2
C2–C3
C2–C4
In–Cl
1.393(4)
1.402(4)
1.494(4)
2.4009(7)
2.7575(4)
N1–C1
N2–C3
N1–C10
N2–C22
C1–C2
C2–C3
In–Inꢀ
N1–In–N2
In–N1–C1
In–N2–C3
C1–C2–C3
In–N1–C10
In–N2–C22
N1–C1–C2
N2–C3–C2
87.55(8)
121.11(18)
121.00(18)
123.9(3)
124.24(17)
122.32(17)
129.0(3)
N1–In–Cl
N2–In–Cl
N1–In–Inꢀ
N2–In–Inꢀ
C1–C2–C4
C3–C2–C4
Cl–In–Inꢀ
103.01(6)
98.85(6)
123.23(6)
124.44(6)
118.5(2)
116.9(2)
114.31(2)
N1–In–N2
In–N1–C1
In–N2–C3
C1–C2–C3
In–N1–C10
N1–C1–C2
N2–C3–C2
N1–In–Cl1
N1–In–Cl2
83.67(8)
120.02(18)
123.70(15)
123.2(2)
123.70(15)
129.1(2)
127.5(2)
146.01(6)
108.61(6)
N1–In–Cl3
Cl2–In–Cl3
Cl2–In–Cl1
In–Cl1–Li
In–Cl3–Li
Cl1–Li–Cl3
Cl1–Li–O1
Cl1–Li–O2
O1–Li–O2
88.82(6)
100.15(3)
105.38(3)
90.56(12)
89.92(13)
86.69(6)
108.2(2)
113.6(2)
116.1(3)
128.6(3)
a Symmetry transformations to generate equivalents atoms: ꢀ −x + 1, −y,
−z.
◦
◦
˚
˚
Table 5 Selected bond lengths (A) and angles ( ) for 8
Table 8 Selected bond lengths (A) and angles ( ) for 12
In–N1
In–N2
N1–C1
N2–C3
N1–C10
N2–C22
C1–C2
2.166(2)
2.150(2)
1.319(3)
1.325(3)
1.448(3)
1.446(3)
1.405(4)
In–N3
In–N4
N3–C34
N4–C46
C2–C3
C2–C4
2.081(2)
2.078(2)
1.400(3)
1.408(3)
1.396(4)
1.405(4)
In1–N1
In1–N2
N1–C1
N2–C3
N1–C10
N2–C22
C1–C2
C2–C3
C2–C4
In1–Cl1
In1–S
2.147(2)
2.142(2)
1.313(4)
1.320(4)
1.450(4)
1.447(4)
1.403(4)
1.402(4)
1.493(4)
2.3454(8)
2.3691(8)
In2–N3
In2–N4
N3–C34
N4–C36
N3–C43
N4–C55
C34–C35
C35–C36
C35–C37
In2–Cl2
In2–S
2.140(2)
2.145(2)
1.317(4)
1.322(4)
1.446(4)
1.434(4)
1.408(4)
1.406(4)
1.494(4)
2.3540(9)
2.3640(8)
N1–In–N2
In–N1–C1
In–N2–C3
C1–C2–C3
In–N1–C10
N1–C1–C2
N2–C3–C2
In–N2–C22
C1–N1–C10
C1–C2–C4
87.10(7)
121.70(17)
122.85(17)
123.9(2)
120.11(15)
128.7(2)
128.1(2)
118.55(15)
118.2(2)
N1–In–N3
N1–In–N4
N2–In–N3
N2–In–N4
N3–In–N4
In–N3–C34
In–N4–C46
C3–N2–C22
C3–C2–C4
107.12(9)
112.84(8)
123.96(9)
103.22(9)
118.47(10)
132.16(18)
119.05(17)
118.1(2)
N1–In1–N2
In1–N1–C1
In1–N2–C3
In1–S–In2
N1–C1–C2
N2–C3–C2
C1–C2–C3
In1–N1–C10
In1–N2–C22
N1–In1–Cl1
N2–In1–Cl1
N1–In1–S
87.50(9)
122.95(19)
122.9(2)
100.47(3)
128.3(3)
128.4(3)
124.0(3)
118.01(18)
119.28(18)
110.59(7)
109.08(7)
110.48(7)
120.60(7)
115.16(3)
117.3(3)
N3–In2–N4
In2–N3–C34
In2–N4–C36
N3–C34–C35
N4–C36–C35
C34–C35–C36
In2–N3–C43
In2–N4–C55
N3–In2–Cl2
N4–In2–Cl2
N3–In2–S
88.31(9)
120.5(2)
121.83(19)
129.4(3)
127.6(3)
123.9(3)
120.27(18)
119.01(18)
105.69(7)
111.51(7)
126.22(7)
104.43(7)
116.54(3)
117.9(3)
119.3(2)
116.4(2)
◦
a
˚
Table 6 Selected bond lengths (A) and angles ( ) for 10
In–N1
In–N2
N1–C1
N2–C3
N1–C10
N2–C22
2.1857(15)
2.1512(15)
1.318(2)
1.330(2)
1.449(2)
1.447(2)
In–Cl
2.3653(5)
2.0954(13)
2.1523(13)
1.403(2)
N4–In2–S
Cl2–In2–S
C34–C35–C37
C36–C35–C37
In–O1
In–O1ꢀ
C1–C2
C2–C3
N2–In1–S
Cl1–In1–S
C1–C2–C4
C3–C2–C4
118.0(3)
1.399(3)
118.4(3)
N1–In–N2
In–N1–C1
In–N2–C3
C1–C2–C3
In–N1–C10
In–N2–C22
C1–N1–C10
C3–N2–C22
O1–In–O1ꢀ
N1–In–O1
O1–In–Cl
86.34(6)
123.45(12)
123.44(12)
124.11(11)
120.16(11)
121.22(11)
116.37(15)
115.15(15)
72.61(6)
N1–C1–C2
N2–C3–C2
C1–C2–C4
C3–C2–C4
N1–In–Cl
N2–In–Cl
N1–In–O1ꢀ
N2–In–O1ꢀ
In–O1–Inꢀ
N2–In–O1
O1ꢀ–In–Cl
128.12(17)
128.33(17)
117.54(16)
117.80(16)
106.43(4)
110.19(4)
153.35(6)
90.25(5)
through the Cl1–Cl3 vector. The In–Cl1(or Cl3) bridge bonds are
˚
ca. 0.2 A longer than the terminal In–Cl2 bond.
The molecular structure of [In(L){N(H)(C6H3Pri2-2,6)}2] (8)
(Fig. 5 and Table 5) has the four-coordinate distorted tetrahedral
In atom as part of an InN4 core. The bonds to the amido
˚
ligands, In–N3(or N4) are almost 0.1 A shorter than those to
107.39(6)
140.69(6)
99.55(4)
the b-dialdiminato ligand, In–N1(or N2). The three widest angles
subtended at the In atom decrease in the sequence N2–In–N3 >
N3–In–N4 > N1–In–N4. The angle In–N–C subtended at N3 is
very much wider than that at N4.
93.68(5)
107.46(4)
a Symmetry transformations to generate equivalents atoms: ꢀ −x, −y, −z.
The molecular structure of the centrosymmetric [{In(Cl)(L)(l-
OH)}2] (10) (Fig. 6 and Table 6) has the five-coordinate distorted
square pyramidal (the terminal Cl or Clꢀ atom is quasi-axial) In
and Inꢀ atoms at the centre of a spiro junction, the InO1InꢀO1ꢀ
rhomboid being its core. The In–Cl distance is closely similar to
the terminal In–Cl (In–Cl2) in 6. Likewise, each of the geometric
The molecular structure of [In(Cl)(L)(l-Cl)2Li(OEt2)2] (6)
(Fig. 4 and Table 4) has the five-coordinate distorted square
pyramidal (the terminal Cl2 atom is quasi-axial) In atom and
the four-coordinate distorted Li atom as part of the buckled four-
membered InCl1LiCl3 ring; this has a fold angle of 22.81(12)◦
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 4449–4460 | 4453
©

View Article Online
◦
˚
Table 9 Selected bond lengths (A) and angles ( ) for 14
In1–N1
In1–N2
In1–Cl1
In1–Cl2
In1–Cl3
In1–O1
Sn1–O1
Sn1–O2
2.315(7)
2.381(6)
2.450(2)
2.522(2)
2.548(2)
2.104(5)
2.048(5)
2.044(5)
In2–N3
In2–N4
In2–Cl4
In2–Cl5
In2–Cl6
In2–O2
Sn2–O1
Sn2–O2
2.331(7)
2.359(6)
2.4520(19)
2.524(2)
2.535(2)
2.111(5)
2.040(5)
2.049(5)
N1–In1–N2
In1–O1–Sn1
Cl1–In1–Cl2
Cl1–In1–Cl3
Cl2–In1–Cl3
Cl1–In1–O1
Cl2–In1–O1
Cl3–In1–O1
O1–Sn1–O2
Sn1–O1–Sn2
O1–In1–N1
Cl1–In1–N2
77.7(2)
124.9(2)
91.78(8)
91.56(8)
166.70(8)
101.85(13)
83.64(15)
83.08(15)
77.9(2)
N3–In2–N4
In2–O2–Sn1
In2–O2–Sn2
Cl4–Sn2–Cl5
Cl4–Sn2–Cl6
Cl6–Sn2–Cl5
Cl4–In2–O2
Cl5–In2–O2
Cl6–In2–O2
O1–Sn2–O2
Sn1–O2–Sn2
77.5(2)
126.2(2)
125.0(2)
101.43(13)
90.14(7)
169.04(8)
84.31(15)
84.31(15)
84.78(15)
77.9(2)
101.0(2)
167.4(2)
168.38(17)
100.9(2)
Fig. 4 The molecular structure of 6 (30% probability ellipsoids).
The molecular structure of the binuclear In(III) sulfide
[{In(Cl)L}2(l-S)] (12) (Fig. 8 and Table 8) has the four-coordinate
distorted tetrahedral In1 and In2 atoms bridged by a sulfide. The
six angles subtended at In1 (or In2) range from 87.5◦ (or 88.3◦) to
120.6◦ (or 126.2◦), with an average of 109◦ (or 108.8◦); hence it is
concluded that each of the formally In(III) lone pairs is implicated
parameters of 10 and of [{In(Cl)(L1)(l-OH)}2] [L1 = {N(C6H3Pri2-
2,6)C(Me)}2CH],13 excluding the substituents at the b- and c-
positions of the L− or [L1]− ligand, are markedly similar.
The molecular structure of the centrosymmetric binuclear
In(II) compound [L(Cl)In–In(Cl)L] (11a) has the four-coordinate
distorted tetrahedral In and Inꢀ atoms joined by the In–Inꢀ bond.
The widest angles subtended at the In atom are N1(or N2)–In–Inꢀ
and the narrowest is the chelating ligand’s bite angle N1–In–N2.
The InII–Cl bond of 11a is longer than the InIII–Cl bond of 10.
Each of the geometric parameters of 11a is essentially identical
to those of 11b and 11c (see ESI†) and also similar, excluding the
substituents at the b- and c-positions of the L− or [L1]− ligand,
to those of [L1(Cl)In–Inꢀ(Cl)L1];13 e.g., the In–Inꢀ distance in the
˚
in p-bonding. The In–Cl distances in 12 are ca. 0.015 A shorter
than in 10. The geometric parameters at the sulfur atom of 12
may be compared with those in [{In(CH(SiMe3)2)2(l-S)}2].18 In
the latter, the sulfur atom was disordered between two positions,
with the angle In1–S–In2 112.4(1) and 116.8(2)◦ and the distances
˚
˚
In1–S 2.419(3) and 2.356(4) A and In2–S 2.433(3) and 2.376(4) A.
The molecular structure of the cyclobis(dimethylstannoxane)-
bridged bis(trichloroindium) complex [{InCl3(tmeda)}2{l-
(OSnMe2)2}] (14) (Fig. 9 and Table 9) has the six-coordinate
˚
latter is 2.8342(7) A.
Table 10 Conformation of the b-dialdiminatometal fragment of crystalline 2–6, 8, 10, 11a and 12
˚
˚
˚
˚
Compound
No.
a/A
0.073
b/A
0.808
c/A
d/A
e/◦
f /◦
g/◦
[Li(L)(thf)2]
[Li(L)(tmeda)]
[Al(L)Cl2]
[Ga(L)Cl2]
[In(Cl)(L)(l-Cl)2Li(OEt2)2]
[In(L){N(H)(C6H3Pri2-2,6)}2]
[{In(Cl)(L)(l-OH)}2]
2
−0.197
0.365
−0.373
−0.396
0.331
−0.547
−0.283
0.385
0.391
0.307
0.376
0.214
−0.357
0.205
−0.372
−0.377
0.267
−0.374
−0.368
0.416
0.379
0.377
0.270
0.450
26.6
40.0
46.9
47.5
40.3
40.4
40.0
39.3
44.8
39.5
39.0
39.6
81.0
79.3
86.5
87.5
74.3
71.4
89.0
78.9
85.4
87.8
88.8
80.4
83.0
61.6
87.6
87.1
85.4
89.6
89.9
88.5
83.4
88.2
78.5
74.8
3
−0.084
−0.662
4
0.103
0.399
5
0.111
0.369
6
−0.122
−0.834
8
0.153
0.537
10
0.069
0.535
−0.145
−0.091
−0.085
−0.114
−0.117
−0.616
−0.626
−0.487
−0.487
−0.592
[L(Cl)In–In(Cl)L]
11a
12
[{In(Cl)L}2(l-S)]
˚
N1C1C3N2 coplanar; atoms out of plane (A) C2, a; M, b; C22, c; C10, d
Dihedral angles (◦): C4 to C9/C1C2C3, e; C22 to C27/MN2C3, f ; C10 to C15/MN1C1, g
4454 | Dalton Trans., 2006, 4449–4460
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
respectively;20 and for [mer-InCl3(py)3], the In–Cl1, In–Cl2,
In–N1 and In–N2 distances are 2.471(8), 2.476(2), 2.377(21)
21a
˚
and 2.302(7) A, respectively. The geometric parameters of the
Sn1O1Sn2O2 ring of the coordinated cyclodistannoxane of 14
may be compared with those in [{SnCl2(Me)2}2{l-(SnMe2(lꢀ-
◦
ꢀ
ꢀ
˚
O))2}] [having Sn–O 2.062(3) A, O–Sn–O 74.2(3) and Sn–O–Sn
105.8(3)◦,17b] and [{SnMe2(nap)}2O]2, having a mean Sn–O
◦
ꢀ
˚
distance of 2.099 A and a mean O–Sn–O angle of 76.8 (nap =
(S)-(+)-6-methoxy-a-methyl-2-naphthaleneaceto anion).22
The geometric parameters of the M(L) fragment in 2–6, 8 and
10–12
Fig. 5 The molecular structure of 8 (30% probability ellipsoids).
The conformation of the M(L) fragment in 2–6, 10, 11a and 12 is
summarised in Table 10. In each of these crystalline complexes, the
a-(N1 and N2) and c-(C1 and C2) atoms are essentially coplanar.
The MN1C1C2C3N2 six-membered ring is then either of the half-
chair or boat conformation; the former is found in 2 and 3 (M = Li)
and 11a (M = In) with M (b in Table 10) out of the N1C1C2C3N2
near-plane, and the latter with b > a (C2 in Table 10) and both out
of the N1C1C3N2 plane. The aryl substituents at N1 and N2 (c
and d, respectively in Table 10) are cis to one another but trans to
C2 and M. The dihedral angle (e in Table 10) between the phenyl
ring at C2 and the C1C2C3 plane is 43.5 4.5◦ for each except
2 (e = 26.6◦). The aryl substituents at N1 and N2 tend towards
orthogonality with respect to the MN1C1 and MN2C3 planes,
respectively (g and f in Table 10); with 3 and 12 being exceptions
for g, and 8 and 6 for f .
distorted octahedral In1 and In2 atoms bridged through the
O1 and O2 atoms of the cyclodistannoxane. At In1, the atoms
N1, N2 and Cl2 are mutually transoid with respect to the O1,
Cl1 and Cl3 atoms, respectively; and for In2, the corresponding
trans-pairs are N3/O2, N4/Cl4 and Cl5/Cl6. The In–Cl bond
˚
trans to an N atom is ca. 0.07 A shorter than that trans to a
˚
Cl atom, while the In–N bond trans to an O atom is ca. 0.08 A
shorter than to a Cl atom. The coordination environment at each
In atom of 14 may be compared to that in InCl3(HX)] [In(HX) =
VI, with the atoms N4/N1, N3/Cl2 and Cl1/Cl3 mutually
trans],19 [InCl3(Y)] [In(Y) = VII, with the atoms N1/Cl2, N2/Cl3
and Cl1/O mutually trans],20 and [mer-InCl3(py)3] (VIII)21a or
its 4-EtC5H4N analogue.21b For [InCl3(HX)] the In–Cl distances
are 2.5775(7), 2.3876(7) and 2.4968(7) for Cl1, Cl2 and Cl3,
The endocyclic bond lengths in the MN1C1C3C2N2 ring reveal
that in each of the crystalline complexes 2–6, 8 and 10–12 there is
p-delocalisation, as evident from the almost identical bond lengths
in each of the M–N1/M–N2, N1–C1/N2–C3 and C1–C2/C2–C3
19
˚
respectively, and In–N3 2.577(9) A; for [InCl3(Y)], the In–Cl1,
In–Cl2, In–Cl3, In–O, In–N1 and In–N2 distances are 2.4381(13),
˚
2.4103(13), 2.4405(13), 2.396(3), 2.306(4) and 2.348(4) A,
Fig. 6 The molecular structure of 10 (30% probability ellipsoids).
The Royal Society of Chemistry 2006 Dalton Trans., 2006, 4449–4460 | 4455
This journal is
©

View Article Online
Fig. 7 The molecular structure of 11a (50% probability ellipsoids).
Fig. 8 The molecular structure of 12 (50% probability ellipsoids).
Comparison between the ligated [{N(C6H3Pri2-2,6)C(H)}2-
CPh]− (≡ L−) and [{N(C6H3Pri2-2,6)C(Me)}2CH]− [≡ (L1)−] is
available for the pairs of metal complexes 2/IV (Li), 4/Va
(Al), 5/Vb (Ga), 10/[{In(Cl)(L1)(l-OH)}2],13 and 11a/[L1(Cl)In–
In(Cl)L1].13 Each of the M(L1) complexes has the MN1C1C2C3N2
˚
˚
ring in the half-chair conformation with M 0.525 A (Al), 0.507 A
II
˚
˚
(Ga), 0.800 and 0.895 A (In hydroxide) and 0.626 A (In 2 complex)
out of the N1C1C2C3N2 plane. The aryl substituents at N1
and N2 of the M(L1) complexes are almost orthogonal to the
N1MN2 plane. The endocyclic bond lengths in these M(L) and
M(L1) complexes are similar, except for the M–N bonds which are
longer in the former. The endocyclic bond angles, however, are
significantly different: that subtended at M, N and C2 is wider for
M(L1) than M(L) complexes, whereas the reverse order is found
for that at C1 and C3.
Fig. 9 The molecular structure of 14 (50% probability ellipsoids).
In conclusion, we report the synthesis, characterisation and
structures of eleven crystalline metal complexes of the lig-
and [{N(C6H3Pri2-2,6)C(H)}2CPh]− (≡ L−) 2–8 and 10–12 in
which M = Li (2, 3), Al (4), Ga (5), InIII (6–8, 10, 12 and 13)
pairs; the latter two pairs shown distances intermediate between
single and double bonds. Likewise, the bond angles in each of
the pairs M–N1–C1/M–N2–C3 and N1–C1–C2/N2–C3–C2 are
closely similar.
4456 | Dalton Trans., 2006, 4449–4460
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
and InII (11). Elemental (C, H, N) analysis (4, 6–8 and 11–13),
EI-MS (4, 6–8 and 10–13), 27Al (4) and 1H and 13C solution NMR
spectral data (2–8 and 11–13) are presented. The X-ray molecular
structures of crystalline H(L) (1), 2–6, 8 and 10–13 show endocyclic
p-delocalisation; that of [{InCl3(tmeda)}2{l-(OSnMe2)2}] (14) is
also described. The endocyclic MN1C1C2C3N2 six-membered
M(L) ring has either the half-chair (2, 3 and 11a) or boat (4–8,
10 and 13) conformation, with M out of the N1C1C3N2 plane
for each and C2 also out of this plane for the boat (the deviation
from the plane being greater for M than C2). The data for the
M(L) and the M[{N(C6H3Pri2-2,6)C(Me)}2CH] [≡ M(L1)] ring
are compared for the isoleptic L1 analogues of 2, 4, 5, 10 and
11, in which the major differences are the endocyclic bond angles
subtended at M, N1, N2 and C2 [wider for M(L1) than M(L)] and
the reverse for those at C1 and C3.
1.38 [d, 24 H, CH(CH3)2, 3J(1H–1H) = 6.7 Hz]; 13C NMR (C6D6):
d 162.4 (NCH); 153.8, 145.8, 141.4, 128.7, 125.5, 123.7, 123.4,
122.7 (aryl); 103.2 (CPh), 57.1 (tmeda); 28.4, 26.2, 23.3 (Pri).
[Al(L)Cl2] (4). Li(L) (0.41 g, 0.76 mmol) was added to AlCl3
(0.10 g, 0.◦76 mmol) in diethyl ether at 0 ◦C. The mixture was stirred
at ca. 25 C for ca. 12 h, then filtered. Volatiles were removed in
vacuo from the filtrate. The residue was extracted with pentane. The
◦
extract was stored at −25 C, yielding blue crystals of 4 (0.39 g,
87%) (Found: C, 70.6; H, 7.64; N, 4.77. C33H41AlCl2N requires
C, 70.3; H, 7.33; N, 4.97%), mp 176 ◦C. 1H NMR (C6D6): d 7.83
(s, 2 H, NCH), 7.54–7.00 (m, 11 H, aryl), 3.67 [sp, 4 H, CHMe2,
3J(1H–1H) = 7.02], 1.43 [d, 12 H, CH(CH3), 3J(1H–1H) = 7.02],
1.11 [d, 12 H, CH(CH3), 3J(1H–1H) = 6.55 Hz]; 13C NMR (C6D6):
d 165.5 (NCH); 144.6, 141.4, 137.9, 129.4, 128.7, 126.7, 124.7
(aryl); 109.2 (CPh); 25.6, 23.5, 23.3 (Pri); 27Al NMR (C6D6): d
100.55; MS (M denotes the parent) m/z (% and assignment): 562
(100, M+), 527 (7, [M − Cl]+).
Experimental
Ga(L)Cl2 (5). Similarly, from of Li(L) (0.64 g, 1.2 mmol) and
GaCl3 (0.21 g, 1.2 mmol) colourless crystals of 5 (0.69 g, 90%)
were obtained. 1H NMR (C6D6): d 7.82 (s, 2 H, NCH), 7.25–7.00
General remarks
All manipulations were performed under argon using stan-
dard Schlenk techniques. Benzene, diethyl ether, thf and hex-
ane were dried using sodium-potassium alloy and stored over
a sodium mirror under argon. Deuterated solvents (C6D6,
C7D8, C4D8O and CDCl3) were freeze/thaw degassed and
3
(m, 11 H, aryl), 3.68 [sp, 4 H, CHMe2, J(1H–1H) = 6.83], 1.47
[d, 12 H, CH(CH3), 3J(1H–1H) = 6.83], 1.09 [d, 12 H, CH(CH3),
3J(1H–1H) = 6.83 Hz]; 13C NMR (C6D6): d 164.5 (NCH); 144.6,
138.4, 129.3, 128.8, 126.6, 126.5, 124.6 (aryl); 107.6(CPh); 25.8,
25.5, 23.5, 23.3 (Pri).
˚
stored over dried 4 A molecular sieves under an argon atmo-
sphere. H[{N(C6H3Pri2-2,6)C(H)}2CPh] [≡ H(L)] (1),6 Li(L),6
and HN(C6H3Pri2-2,6)(SiMe3)23 were synthesised by published
procedures. The NMR spectra were recorded on a Bruker DPX
300 (300.1 MHz for 1H, 75.5 MHz for 13C and 116.6 MHz
for 7Li) or AMX 500 (130.31 MHz for 27Al) instruments and
referenced externally (7Li, using LiCl; 27Al, using aqueous Al(OH)3
with a D2O lock), or internally (1H and 13C) to the residual
solvent resonances. Unless otherwise stated, all NMR spectra were
[In(Cl)(L)(l-Cl)2Li(OEt2)2] (6). A solution of n-butyllithium
in hexane (2.5 cm3, 4.00 mmol) was added dropwise with stirring
to a solution◦of H(L) (1) (1.52 g, 3.26 mmol) in diethyl et◦her
(20 cm3) at 0 C. Stirring was continued for ca. 2 h at ca. 25 C,
then the solution was added dropwise to a suspension of InCl3
(0.73 g, 3.30 mmol) in diethyl ether (20 cm3). The mixture was set
aside for ca. 48 h and then filtered. Concentration of the filtrate in
vacuo yielded yellow crystals of 6 (2.19 g, 80%) (Found: C, 58.75;
H, 6.98; N, 3.18. C41H61Cl3InLiN2O2 requires C, 58.5; H, 7.30; N,
3.33%), mp 61–62 ◦C (decomp.). 1H NMR (C6D6): d 7.75 (s, 2 H,
1
measured at 293 K and other than H were proton-decoupled.
Electron impact mass spectra were taken from solid samples
using a Kratos MS 80 RF instrument. Melting points were taken
in sealed capillaries and are uncorrected. Elemental analyses
were determined by Medac Ltd., Brunel University (analyses for
complexes 2 and 3 were not carried out due to their high sensitivity
to air and moisture).
3
NCH), 7.13–7.00 (m, 11 H, aryl), 3.68 [sp, 4 H, CHMe2, J(1H–
3
1H) = 6.7], 3.26 [q, 8 H, OCH2, J(1H–1H) = 7.0], 1.38 [d, 12
H, CH(CH3), 3J(1H–1H) = 6.7], 1.12 [t, 12 H, OCH2CH3, 3J(1H–
3
1H) = 7.0], 1.04 [d, 12 H, CH(CH3), J(1H–1H) = 6.7 Hz]; 13C
NMR (C6D6): d 166.2 (NCH); 143.7, 139.8, 129.3, 128.4, 127.0,
126.4, 124.6 (aryl); 106.8 (CPh); 65.9 (OCH2); 29.0, 25.6, 23.3
(Pri); 15.5 (OCH2CH3). MS (M denotes the parent) m/z (% and
assignment): 650 (83, [M − LiCl − 2Et2O]+).
Preparations
[Li(L)(thf)2] (2). A solution of n-butyllithium in hexane
(3.42 cm3, 6.0 mmol) was added to a stirred solution of H◦(L)
(2.56 g, 6.0 mmol) in thf (20 cm3) at 0 ◦C. After 1 h at ca. 25 C,
volatiles were removed in vacuo and hexane (15 cm3) was added.
Cooling at −25 ◦C yielded yellow crystals of 2 (3.71 g, 96%). 1H
NMR (C6D6): d 8.09 (s, 2 H, NCH); 7.50 (m, 2 H), 7.17 (m, 8 H),
7.00 (m, 1 H) (aryl); 3.49 [sp, 4 H, CHMe2, 3J(1H–1H) = 7.02], 3.27
(t, 8 H, CH2O), 1.22 [d, 24 H, CH(CH3)2, 3J(1H–1H) = 6.90 Hz],
1.17 (q, 8 H, CH2CH2O); 13C NMR (C6D6): d 161.8 (NCH); 152.8,
145.7, 141.8, 129.1, 126.8, 126.0, 123.3 (aryl); 104.7 (CPh), 68.45
(CH2O), 28.8 (CH2CH2O); 25.7, 25.1, 24.0 (Pri).
[In(Cl)(L){N(H)(C6H3Pri2-2,6)}] (7). A solution of 6 (1.10 g,
1.31 mmol) in diethyl ether (20 cm3) was added to a stirred
suspension of K[N(H)(C6H3Pri2-2,6)] (0.28 g, 1.30 mmol) in Et2O
(20 cm3) at ca. 25 ◦C. The mixture was set aside for 24 h with
stirring, then filtered. The yellow filtrate was concentrated to yield
yellow microcrystals of 7 (0.73 g, 71%) (Found: C, 68.2; H, 7.67;
N, 5.04. C45H59ClInN3 requires C, 68.2; H, 7.51; N, 5.30%), mp
◦
1
214–216 C. H NMR (C6D6): d 7.80 (s, 2 H, NCH), 7.16–6.91
(m, 14 H, aryl), 3.78 (sp, 2 H, CHMe2), 3.48 (sp, 2 H, CHMe2),
3.05 (s, 1 H, NH), 2.35 (sp, 2 H, CHMe2), 1.42 (d, 6 H, CHCH3),
1.31 (d, 6 H, CHCH3), 1.07 (d, 12 H, CHCH3), 0.95 (d, 12 H,
CHCH3); 13C NMR (C6D6): d 165.5 (NCH); 145.0, 144.1, 143.0,
137.9, 129.2, 127.9, 126.8, 126.1, 125.4, 123.9, 123.0, 120.2 (aryl);
106.8 (CPh); 29.6, 28.8, 28.4, 25.9, 25.7, 24.0, 23.8, 22.5 (Pri). MS
Li(L)(tmeda) (3). This was obtained in high yield from 2 and
tmeda. 1H NMR (C6D6): d 8.20 (s, 2 H, NCH), 7.62 [d, 2 H, J(1H–
1H) = 7.7], 7.34–7.28 (m, 8 H), 7.12 [t, 1 H, J(1H–1H) = 7.3] (aryl);
3.61 [sp, 4 H, CHMe2, J(1H–1H) = 6.7], 1.89 (s, 16 H, tmeda),
3
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 4449–4460 | 4457
©

View Article Online
(M denotes the parent) m/z (% and assignment): 791 (21, M+),
756 (12, [M − Cl]+), 615 (92, [M − N(H)(C6H3Pri2-2,6)]+).
1.28 (d, 12 H, CHCH3), 1.18 (d, 12 H, CHCH3), 1.03 (d, 12 H,
CHCH3); 13C NMR (C6D6): d 166.9 (NCH); 146.9, 146.7, 145.4,
142.4, 140.7, 129.3, 127.2, 124.9, 124.1, 124.0 (aryl); 105.9 (CPh);
29.4, 29.2, 27.3, 26.4, 26.0, 24.8, 24.0, 23.1, 22.9 (Pri).
[In(L){N(H)(C6H3Pri2-2,6)}2]
(8). K[N(H)(C6H3Pri2-2,6)]
(0.72 g, 3.34 mmol) was added to a stirred solution of 6 (1.43 g,
1.70 mmol) at ca. 25 ◦C. The mixture was set aside for ca.
12 h with stirring, then filtered. The bright yellow filtrate was
concentrated to afford yellow crystals of 8 (1.26 g, 79%) (Found:
C, 73.6; H, 8.89; N, 5.62.◦C57H77InN4 requires C, 73.4; H, 8.32;
(c) A solution of Na(L) (2.19 g, 4.48 mmol) in thf (40 cm3)
was added to a suspension of InCl (0.74 g, 4.92 mmol) in thf
(20 cm3) at ca. 25 ◦C. There was an immediate colour change
from orange to light yellow, accompanied by the formation of a
grey precipitate. The mixture was set aside for ca. 12 h, whereafter
a further portion of InCl (0.32 g) was added (because a bright
silver-coloured deposit of In was observed). After ca. 48 h at ca.
25 ◦C, the mixture was filtered. The filtrate upon concentration
1
N, 6.00%), mp 204–205 C. H NMR (C6D6): d 7.79 (s, 2 H,
NCH), 7.27–7.00 (m, 15 H, aryl), 6.86 (t, 2 H, aryl); 3.41 (sp, 4
H, CHMe2), 3.14 (br, 2 H, NH), 1.16–1.00 (m, 48 H, CHCH3);
13C NMR (C6D6): d 164.8 (NCH); 147.4, 145.4, 143.9, 140.8,
137.3, 129.3, 129.1, 126.2, 126.1, 125.8, 124.7, 124.6, 123.0,
118.9 (aryl); 106.9(CPh); 28.8, 28.4, 26.4, 24.4, 23.2 (Pri). MS
(M denotes the parent) m/z (% and assignment): 933 (4.0,
M+), 757 (58, [M − {N(H)(C6H3Pri2-2,6)}]+), 580 (51, [M −
2{N(H)(C6H3Pri2-2,6)}]+).
◦
in vacuo and cooling at −27 C furnished yellow crystals of the
1 : 1 thf adduct of 11 (1.74 g, 60%) (Found: C, 64.4; H, 7.09; N,
4.18. C70H90Cl2In2N4O requires C, 64.5; H, 6.96; N, 4.30%), mp
154–155 ◦C. 1H NMR (C4D8O): d 7.61 (s, 4 H, NCH), 7.11–6.99
(m, 22 H, aryl), 3.53 (m, 8 H, CHMe2), 1.29 (d, 12 H, CHCH3),
1.08–1.00 (m, 24 H, CHCH3); 13C NMR (C4D8O): d 166.9 (NCH),
166.5 (NCH); 156.4, 147.2, 146.5, 146.0, 144.6, 144.2, 143.6, 142.9,
142.3, 141.3, 129.4, 129.2, 127.9, 127.7, 127.3, 127.0, 126.9, 126.7,
126.1, 125.7, 124.3, 124.1, 123.8 (aryl); 107.3, 106.6, 105.9 (CPh);
29.4, 29.3, 29.1, 26.3, 23.9, 23.2 (Pri).
[{In(Cl)(L)(l-OH)}2] (10).
A solution of Li[N(SiMe3)-
(C6H3Pri2-2,6)] was prepared in situ by the addition of a 1.6 M
solution of LiBun in hexane (1.6 cm3) to HN(SiMe3)(C6H3Pri2-2,6)
(0.42 g, 1.68 mmol) in Et2O (20 cm3) at ca. 25 ◦C. The solution was
set aside for ca. 2 h, whereafter 6 (1.35 g, 1.60 mmol) was added. A
colourless precipitate was formed instantly; the mixture was stirred
for ca. 12 h, then filtered. The yellow filtrate was concentrated to
ca. 10 cm3 in the open laboratory. Cooling to −27 ◦C yielded
yellow microcrystals, which upon recrystallisation from thf/Et2O
[{In(Cl)L}2(l-S)] (12). A solution of 11 (1.43 g, 1.10 mmol) in
thf (20 cm3) was added to a solution of sulfur (80.2 mg, 2.50 mmol)
in thf (10 cm3) at ca. 25 ◦C. The mixture was stirred for ca.
48 h, then filtered. The filtrate was concentrated in vacuo and
Et2O (15 cm3) was added, yielding yellow crystals of 12 (0.64 g,
46%) (Found: 62.4; H, 6.58; N, 4.26. C66H82Cl2In2N4S requires C,
◦
afforded colourless crystals of 10 (0.11 g, 10%), mp 206–207 C,
◦
1
which were insoluble in a wide selection of aprotic solvents. MS
(M denotes the parent) m/z (% and assignment): 1266 (0.1, [M −
thf]+), 1247 (0.2, [M − thf − H3O]+), 1212 (0.2, [M − thf − H3O −
Cl]+), 651 (35, [(M − thf)/2 + H3O]+), 581 (27, [(M − thf)/2 +
H2O − Cl]+).
62.7; H, 6.54; N, 4.19%), mp 213–215 C (decomp.). H NMR
(C4D8O): d 7.65 (s, 4 H, NCH), 7.07–6.86 (m, 22 H, aryl), 3.46
(m, 4 H, CHMe2), 1.31 (m, 12 H, CHCH3), 1.05–0.99 (m, 36 H,
CHCH3); 13C NMR (C4D8O): d 165.4 (NCH); 144.9, 144.1, 143.2,
141.0, 126.8, 125.8, 124.6, 123.6 (aryl); 105.8 (CPh); 29.5, 28.4,
26.0, 25.9, 23.8, 22.6 (Pri). MS (M denotes the parent) m/z (%
and assignment): 1264 (21, M+), 1225 (10), 797 (15), 650 (32), 465
(100, L+).
[L(Cl)In–In(Cl)L] (11). (a) A solution of 6 (2.44 g, 2.90 mmol)
in Et2O (50 cm3) was introduced into a Schlenk tube containing a
sodium mirror (180 mg, 7.83 mmol) at ca. 25 ◦C. A grey precipitate
was instantly formed. The mixture was set aside for ca. 48 h, then
filtered. The yellow filtrate afforded a yellow precipitate (0.13 g),
which was filtered off. Volatiles were removed from the filtrate
in vacuo and the residue was extracted into thf. The extract was
cooled at −15 ◦C to afford crystals of 11a (0.68 g, 54%) (Found:
C, 64.0; H, 6.92; N, 4.55. C66H82Cl2In2N4 requires C, 64.35; H,
6.71; N, 4.55%), mp 161–162 ◦C (decomp). 1H NMR (CDCl3): d
7.78 (s, 4 H, NCH), 7.65 (s, 4 H, NCH), 7.36–7.20 (m, 18 H, aryl),
3.44 (m, 8 H, CHMe2), 1.44 (d, 24 H, CHCH3), 1.28 (d, 24 H,
CHCH3); 13C NMR (CDCl3): d 166.0 (NCH); 144.6, 143.7, 142.1,
129.2, 128.2, 126.2, 124.4, 123.5 (aryl); 106.7(CPh); 28.9, 25.9,
23.2 (Pri). MS (M denotes the parent) m/z (% and assignment):
650 (46, [InLCl2]+), 615 (13, [M/2]+), 580 (35, [InL]+).
[InCl2(L)(tmeda)] (13). Tmeda (0.18 cm3) was added dropwise
to a solution of 6 (1.35 g, 1.60 mmol) in Et2O (30 cm3) at ca.
25 ◦C. The mixture was stirred for ca. 12 h, then filtered. The pale
yellow prec◦ipitate was washed with Et2O, then crystallised from
thf at −27 C, furnishing pale microcrystals of 13 (0.72 g, 77%)
(Found: C, 60.8; H, 7.70; N, 7.09. C39H57Cl2InN4 requires C, 61.0;
H, 7.48; N, 7.30%), mp 196–197 ◦C. 1H NMR (C4D8O): d 7.68 (s, 2
H, NCH), 7.22–7.01 (m, 11 H, aryl), 3.48 (sp, 4 H, CHMe2), 2.24
(s, 4 H, NCH2), 2.11 (s, 12 H, NMe2), 1.26 (d, 12 H, CHCH3),
1.10 (d, 12 H, CHCH3); 13C NMR (C4D8O): d 166.6 (NCH), 156.5
(NCH); 144.7, 142.4, 129.3, 127.4, 127.0, 124.3, 123.9 (aryl); 106.5
(CPh); 58.7, 46.4 (tmeda); 29.3, 25.9, 23.4 (Pri). MS (M denotes
the parent) m/z (% and assignment): 650 (89, [M − tmeda]+), 615
(8, [M − tmeda − Cl]+).
(b) The mother liquor from the preparation of 10 was con-
centrated yielding a yellow powder (1.02 g). This was heated in
toluene (50 cm3) at 100 ◦C for 24 h and then filtered. The filtrate
was concentrated and hexane (20 cm3) was added, affording the
hexane 1:1 adduct of 11 (0.12 g, 11%) (Found: C, 65.8; H, 7.64;
N, 4.46. C72H98Cl2In2N4 requires C, 65.6; H, 7.36; N, 4.25%), mp
[{InCl3(tmeda)}2(l-OSn(Me2)OSnMe2})]
(14). Tmeda
(0.15 cm3) was added to a solution of 6 (0.84 g, 1.00 mmol) in
Et2O (20 cm3) at ca. 25 ◦C. After ca. 2 h, the mixture was filtered.
The yellow precipitate was washed with Et2O (2 × 10 cm3) and
dissolved in thf (20 cm3). Hexamethylditin (0.21 cm3, 1.01 mmol)
was added. The mixture was heated with stirring at 50 ◦C for
◦
1
218–219 C. H NMR (C6D6): d 7.76 (s, 4 H, NCH), 7.22–6.96
(m, 22 H, aryl); 3.74 (sp, 8 H, CHMe2), 1.44 (d, 12 H, CHCH3),
4458 | Dalton Trans., 2006, 4449–4460
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 4449–4460 | 4459
©

View Article Online
12 h, then filtered. Concentration of the filtrate and cooling at
−25 ◦C afforded colourless crystals of 14 (0.09 g, 16%), which
was characterised solely by X-ray diffraction.
7 Y. Cheng, P. B. Hitchcock, M. F. Lappert and M. Zhou, Chem.
Commun., 2005, 752.
8 (a) M. S. Hill and P. B. Hitchcock, Chem. Commun., 2004, 1818;
(b) M. S. Hill, P. B. Hitchcock and R. Pongtavornpinyo, Dalton Trans.,
2005, 273.
X-Ray crystallographic study
9 I. W. Davies, J. F. Marcoux, J. Wu, M. Palucki, E. G. Corley, M. A.
Robbins, N. Tsou, R. G. Ball, P. Dormer, R. D. Larsen and P. J. Reider,
J. Org. Chem., 2000, 65, 4571.
10 M. Stender, R. J. Wright, B. E. Eichler, J. Prust, M. M. Olmstead, H. W.
Roesky and P. P. Power, J. Chem. Soc., Dalton Trans., 2001, 3465.
11 (a) B. Quain, D. L. Ward and M. R. Smith, Organometallics, 1998, 17,
3070; (b) M. Stender, B. E. Eichler, N. J. Hardman, P. P. Power, J. Prust,
M. Noltemeyer and H. W. Roesky, Inorg. Chem., 2001, 40, 2794; (c) N.
Kuhn, J. Fahl, S. Fuchs, M. Steinmann, G. Henkel and A. H. Maulitz,
Z. Anorg. Allg. Chem., 1999, 625, 2108.
12 (a) Y. M. Yao, Z. Q. Zhang, H. M. Peng, Y. Zhang, Q. Shen and J.
Lin, Inorg. Chem., 2006, 45, 2175; (b) Y. J. Luo, Y. M. Yao, Y. Zhang,
Q. Shen and K. B. Yu, Chin. J. Chem., 2004, 22, 187; (c) Z. Q. Zhang,
Y. M. Yao, Y. Zhang, Q. Shen and W. T. Wong, Inorg. Chim. Acta, 2004,
357, 3173; (d) Z. Q. Zhang, Q. Shen, Y. Zhang, Y. M. Yao and J. Lin,
Inorg. Chem. Commun., 2004, 7, 305; (e) Y. M. Yao, M. Q. Xue, Y. J.
Luo, Z. Q. Zhang, R. Jiao, Y. Zhang, Q. Shen, W. T. Wong, K. B. Yu
and J. Sun, J. Organomet. Chem., 2003, 678, 108; (f) P. B. Hitchcock,
A. V. Khvostov, M. F. Lappert, A. G. Avent, P. B. Hitchcock, A. V.
Khvostov, M. F. Lappert and A. V. Protchenko, Dalton Trans., 2004,
2272, and unpublished work cited therein.
Diffraction data for compounds 1–6, 8, 10, 11a, 11b, 11c, 12
and 14 were collected at 173(2) K on an Enraf-Nonius Kappa-
CCD diffractometer using monochromated Mo-Karadiation, k =
˚
0.71073 A. Crystals were directly mounted on the diffractometer
under a stream of cold nitrogen gas. The hydrogen atoms of
the l-OH groups of 10 were located on a difference map and
refined. Absorption corrections were not applied for 1–5, but for
the remaining structures were corrected by MULTISCAN. The
structures were refined on all F2 using SHELXL 97.24 Further
details are given in Table 11.
CCDC reference numbers 609658–609670
For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b607782j
Acknowledgements
13 M. Stender and P. P. Power, Polyhedron, 2002, 21, 525.
14 M. S. Hill, P. B. Hitchcock and R. Pongtavornpinyo, Science, 2006,
331, 1904.
15 N. Kuhn, S. Fuchs, E. Niquet, M. Richter and M. Z. Steinmann,
Z. Anorg. Allg. Chem., 2002, 628, 717.
16 M. A. Edelman, P. B. Hitchcock and M. F. Lappert, J. Chem. Soc.,
Chem. Commun., 1990, 1116.
We thank the Royal Society for the award of a Sino–British
Fellowship to Y. C., Dr Yu. Gun’ko for support of D. J. D. and Dr
A. V. Protchenko for helpful discussions.
17 (a) D. Dakternieks, K. Jurkschat, S. van Dreumel and E. R. T. Tiekink,
Inorg. Chem., 1997, 36, 2023; (b) M. G. Janzen, M. C. Jennings and
R. J. Puddephatt, Organometallics, 2001, 20, 4100.
18 W. Uhl, R. Graupner and H. Reuter, J. Organomet. Chem., 1996, 523,
227.
References
1 L. Bourget-Merle, M. F. Lappert and J. R. Severn, Chem. Rev., 2002,
102, 1031.
2 P. B. Hitchcock, M. F. Lappert and D.-S. Liu, J. Chem. Soc., Chem.
Commun., 1994, 1699.
3 S. K. Ibrahim, A. V. Khvostov, M. F. Lappert, L. Maron, L. Perrin,
C. J. Pickett and A. V. Protchenko, Dalton Trans., 2006, 2591.
4 P. B. Hitchcock, M. F. Lappert and A. V. Protchenko, Chem. Commun.,
2005, 951.
19 S. Das, C.-H. Hung and S. Goswami, Inorg. Chem., 2003, 42, 5153.
20 R. J. Baker, C. Jones, M. Kloth and D. P. Mills, New J. Chem., 2004,
28, 207.
21 (a) S. E. Jeffs, R. W. H. Small and I. J. Worrall, Acta Crystallogr., Sect.
C, 1984, 40, 1329; (b) M. Green, S. Norager, P. Moriarty, M. Motevalli
and P. O’Brien, J. Mater. Chem., 2000, 10, 1939.
5 (a) P. B. Hitchcock, M. F. Lappert and J. E. Nycz, Chem. Commun.,
2003, 1142; (b) P. J. Ragogna, N. Burford, M. D’eon and R. McDonald,
Chem. Commun., 2003, 1052.
6 D. J. E. Spenser, N. W. Aboelella, A. M. Reynolds, P. L. Holland and
W. B. Tolman, J. Am. Chem. Soc., 2002, 124, 2108.
22 A. Dea´k and G. Ta´rka´nyi, J. Organomet. Chem., 2006, 691, 1693.
23 Y.-W. Chao, P. A. Wexler and D. E. Wigley, Inorg. Chem., 1989, 28,
3860.
24 G. M. Sheldrick, SHELXL-97, University of Go¨ttingen, Go¨ttingen,
Germany, 1997.
4460 | Dalton Trans., 2006, 4449–4460
This journal is
The Royal Society of Chemistry 2006
©