Synthesis of a ruthenium bis(diisopropylamino(isocyano)borane) complex from the activation of an amino(cyano)borane

Article abstract of DOI:10.1039/c2dt32274a

The reactivity of the amino(cyano)borane ⁱPr₂NBH(CN) (2) towards [RuH₂(η²-H₂) ₂(PCy₃)₂] (3) was investigated. Our study reveals that the formation of the bis(isocyanoborane) ruthenium complex [RuH(CN)(CN-BHNⁱPr₂)₂(PCy₃) ₂] (6) occurs via the intermediacy of the bis(σ-B-H) ruthenium complex [RuH(CN)(H₂BNⁱPr₂)(PCy ₃)₂] (5). This transformation involves BCN linkage isomerisation in 2. The diisopropylaminoborane ligand in 5 can be displaced to ultimately produce the bis(σ-borane) complex [RuH₂(η ²:η²-H₂BNⁱPr₂) (PCy₃)₂] (4) as a by-product.

Full text of DOI:10.1039/c2dt32274a

Dalton
Transactions
View Article Online
View Journal
PAPER
Synthesis of a ruthenium bis(diisopropylamino-
(isocyano)borane) complex from the activation of an
Cite this: DOI: 10.1039/c2dt32274a
amino(cyano)borane†
Maximilian Joost,a,b Gilles Alcaraz,*a,b Laure Vendier,a,b
Amalia Poblador-Bahamonde,c Eric Clotc and Sylviane Sabo-Etienne*a,b
i
The reactivity of the amino(cyano)borane Pr2NBH(CN) (2) towards [RuH2(η2-H2)2(PCy3)2] (3) was investi-
gated. Our study reveals that the formation of the bis(isocyanoborane) ruthenium complex [RuH(CN)-
(CN-BHNiPr2)2(PCy3)2] (6) occurs via the intermediacy of the bis(σ-B–H) ruthenium complex [RuH(CN)-
(H2BNiPr2)(PCy3)2] (5). This transformation involves BCN linkage isomerisation in 2. The diisopropylamino-
borane ligand in 5 can be displaced to ultimately produce the bis(σ-borane) complex [RuH2(η2:η2-
H2BNiPr2)(PCy3)2] (4) as a by-product.
Received 27th September 2012,
Accepted 19th November 2012
DOI: 10.1039/c2dt32274a
www.rsc.org/dalton
As a result, boron substituted isocyanide metal complexes
Introduction
of general formulation LnM(CvN-BR1R2) are scarce and mostly
Isonitriles (R–NvC:) are well known organic molecules and limited to group 6 transition metals (Cr, Mo, W).12–14 Their
their role as ligands in coordination chemistry has been well syntheses are restricted to salt elimination from organometal-
documented.1–4 Often considered as CO analogues, isonitriles lic nucleophiles [M(CO)5(CN)]− and suitable haloboranes,12,13
coordinate to transition metal centers via a σ/π synergistic or to isomerization of the BCN linkage of a B-cyanoborane
bonding scheme. They generally exhibit a more pronounced upon coordination to chromium.12,14,15
σ-donor ability5 than CO, although the π-acceptor character is
As part of our ongoing program on the chemistry of σ-com-
strongly influenced by the nature of the substituent at the plexes and more particularly on bis(σ-borane) and agostic
nitrogen atom.6 ‘Functionalized’ isocyanides have received borane complexes,16–20 we addressed the synthesis of the
i
little attention.7 In particular, introduction at nitrogen of a amino(cyano)borane Pr2NBH(CN) (2) and its reactivity with
pull group such as a boryl substituent,8–11 likely to stabilize the the ruthenium precursor [RuH2(η2-H2)2(PCy3)2] (3). We report
lone pair in the adjacent position, has been rarely explored here the isolation and the characterization of a new cyano
(Fig. 1).
ruthenium bis(isocyano)borane complex. The reaction takes
place via the intermediacy of a bis-σ borane complex. Our
study shows that isomerization of the BCN linkage in 2 drives
the reaction by displacement of the diisopropylaminoborane
fragment.
Results and discussion
Fig. 1 Functionalized isocyanide complexes.
The strategy for the synthesis of cyanoborane 2 was first based
on the dehydrogenation of the amine-borane precursor 1. The
stoichiometric reaction of diisopropylammonium chloride
with sodium cyanoborohydride did not lead to 1 but to the cor-
responding ammonium borohydride ion pair (iPr2NH2,
BH3CN), even after a prolonged reaction time in refluxing THF.
1 could be cleanly obtained by the reaction of diisopropyl-
amine with oligomeric cyanoborane according to a modified
literature procedure developed by Spielvogel et al.21,22 Unfortu-
nately, and despite all our efforts, cyanoborane 2 could not be
aCNRS, LCC (Laboratoire de Chimie de Coordination), BP44099, 205 route de
Narbonne, F-31077 Toulouse cedex 4, France. E-mail: sylviane.sabo@lcc-toulouse.fr,
gilles.alcaraz@lcc-toulouse.fr
bUniversité de Toulouse, UPS, INPT, F-31077 Toulouse, France
cInstitut Charles Gerhardt, CNRS 5253, Université Montpellier 2, cc 1501, Place
Eugène Bataillon, 34095 Montpellier, France. E-mail: eric.clot@univ-montp2.fr
†Electronic supplementary information (ESI) available: NMR and computational
details 1 : 3. CCDC 894081. For ESI and crystallographic data in CIF or other elec-
tronic format see DOI: 10.1039/c2dt32274a
This journal is © The Royal Society of Chemistry 2012
Dalton Trans.

View Article Online
Paper
Dalton Transactions
cyanoborane ruthenium complex such as 7 could be observed
in the reaction mixture (Scheme 2).
The bis(σ-B–H) diisopropylamino ruthenium complex
[RuH2(η2:η2-H2BNiPr2)(PCy3)2] (4) was clearly identified by
NMR spectroscopy by comparison with the data of an auth-
entic sample prepared independently from diisopropylamino-
borane (iPr2NBH2) and [RuH2(η2-H2)2(PCy3)2] (3).18
Complex [RuH(CN)(CN-BHNiPr2)2(PCy3)2] (6) was fully
characterized by multinuclear NMR spectroscopy and single-
crystal X-ray diffraction. The 31P{1H} NMR spectrum of 6 shows
a singlet at δ 56.40 for the two magnetically equivalent PCy3.
1
The 11B{1H} NMR spectrum displays a signal at δ 22.6. The H
NMR spectrum exhibits a triplet hydride resonance at δ −7.56
that sharpens into a singlet upon phosphorus decoupling. The
hydride atom is cis to two PCy3 ligands, as indicated by the
small coupling constant value (2JHP = 22.7 Hz). The presence of
two signals at δ 4.46 and 4.38 that sharpen upon boron decou-
pling is indicative of two non-equivalent uncoordinated BH
groups. The presence of two sets of two septets at δ 4.55 and
δ 4.17, and at δ 2.97 and δ 2.86, respectively, and of two sets of
two doublets at δ 1.13 and δ 1.01, and at δ 1.05 and δ 0.97,
respectively, is in favour of two non-equivalent B(H)NiPr2 con-
taining ligands at ruthenium. In solution, the geometry
around the metal center in 6 was supported by 13C{31P}, 13C
{1H;31P} (ESI Fig. S6–S9†) and [13C{1H}, 1H]-HMBC experiments
(Fig. 2). The 13C{1H} NMR spectrum exhibits a well-resolved
triplet at δ 141.27 for the cyano ligand cis to two PCy3 as indi-
cated by the small JCP coupling constant of 15 Hz. Two iso-
cyano CNB resonances appear as deshielded triplets at δ
196.55 and 195.86 with a small cis JCP coupling constant of
12 Hz and 7 Hz, respectively. These isocyanide values are com-
parable to those reported by Caulton et al. for the mono isocya-
nide hydrido chloro Ru(II) complex [RuHCl(CN-Et)(PiPr3)2] (δ
Scheme 1 Synthesis of diisopropylamine-cyanoborane 1 and diisopropylamino-
(cyano)borane 2.
cleanly generated by a simple dehydrogenation from 1. The
cyano/halogen exchange reaction from iPr2NBHCl and
Me3SiCN23 circumvented the problem and afforded 2 that was
isolated in 85% yield and characterized by multinuclear NMR
spectroscopy (Scheme 1).
The 11B NMR spectrum of 2 displays a doublet at δ 24.7
(1: δ −23.8, t) with a JBH coupling constant of 143 Hz. In the
13C{1H} NMR spectrum, the cyano carbon atom exhibits a
broad quartet at δ 125.30 with a coupling constant of 98 Hz,
indicative of the B–CN linkage in 2. The IR spectrum of 2 exhi-
bits a peak at 2200 cm−1 in the expected region for the nitrile
CN vibration.14
The reaction of 2 (1.5 equiv.) with [RuH2(η2-H2)2(PCy3)2] (3),
in C6D6 at room temperature, led to the complete disappear-
ance of the starting ruthenium complex and the formation of
complexes 4, 5 and 6 in a 1 : 1 : 1 integration ratio, respectively,
according to 31P{1H} and 1H NMR spectra. In the presence of 3
equiv. of 2, only complexes 4 and 6 were observed in a 1 : 3
integration ratio, respectively (ESI Fig. S1–S5†). No
2
182, cis JPC = 12 Hz).24 The same authors reported that, when
monitoring by 31P NMR the reaction of methylisocyanide with
[RuHCl(PiPr3)2]2, the bis isocyanide species [RuHCl(CN-Me)2-
(PiPr3)2] was transiently observed prior to the mono isocyanide
complex [RuHCl(NC-Me)(PiPr3)2].24
Scheme 2 Reactivity of 2 with complex 3.
Fig. 2
[
13C{1H}, 1H]-HMBC NMR experiment of 6 in C6D6.
Dalton Trans.
This journal is © The Royal Society of Chemistry 2012

View Article Online
Dalton Transactions
Paper
Complex 5 was fully characterized by multinuclear NMR
spectroscopy from a C6D6 solution of 4, 5 and 6 in equimolar
ratio. The data obtained for 5 are in agreement with a diisopro-
pylaminoborane unit bis(σ-B–H) coordinated to the 14 valence
electron [RuH(CN)(PCy3)2] fragment. In the 31P{1H} NMR spec-
trum, 5 shows a singlet at δ 61.3 for the two equivalent PCy3
ligands, more shielded than in 4 (δ 77.8). The 13C{1H}NMR
spectrum exhibits a well-resolved triplet at δ 141.73 (2JCP = 17.5
Hz) for the cyano group (ESI Fig. S6†). In the 1H NMR spec-
trum, in the hydride zone, a set of three signals in a 1 : 1 : 1
integration ratio was observed: two broad signals at δ −4.10
and δ −11.79, and a triplet of doublets at δ −11.60. The broad
signals sharpened upon boron decoupling whereas the other
one collapsed into a doublet upon phosphorus decoupling
allowing the measurement of a 2JHH coupling constant value of
6 Hz (ESI Fig. S2, S3†). Complex 5 displays NMR data similar
to those reported for the ruthenium complex RuHCl(η2:η2-
H2BNMe2)(PCy3)2.25
Table 1 Selected geometrical parameters (distances in Å, angles in °) for the
experimental and calculated structures 6a/6b and 6’, respectively
Experimental
6a/6b
Computed
6′
Ru1–P1
Ru1–P2
Ru1–C15
Ru1–C8
Ru1–C1
Ru1–Hy1
C15–N5
C1–N1
N1–B1
B1–N2
B1–H1
C8–N3
2.3478(10)/2.3488(11)
2.3629(11)/2.3617(11)
2.088(4)/2.088(4)
1.920(4)/1.925(4)
1.972(4)/1.964(4)
1.69(4)/1.56(6)
1.108(5)/1.121(5)
1.178(5)/1.173(5)
1.449(6)/1.454(6)
1.385(6)/1.356(7)
1.11(4)/1.09(5)
2.398
2.405
2.063
1.911
1.958
1.642
1.174
1.190
1.442
1.397
1.196
1.198
1.442
1.398
1.197
1.184(5)/1.186(5)
1.477(6)/1.458(6)
1.371(6)/1.388(6)
1.15(5)/1.24(4)
N3–B2
B2–N4
B2–H2b
P1–Ru1–P2
Ru1–C1–N1
Ru1–C8–N3
C1–N1–B1
C8–N3–B2
Ru1–C15–N5
N1–B1–N2
N3–B2–N4
156.15(4)/159.51(4)
173.4(4)/174.9(3)
178.2(3)/177.8(4)
169.1(4)/172.7(4)
155.4(4)/155.2(4)
178.5(4)/177.6(4)
120.0(4)/121.6(5)
122.1(5)/121.2(4)
157.40
174.23
176.14
179.99
159.96
176.23
121.72
122.84
The X-ray structure of 6 was determined at 110 K. As illus-
trated in Fig. 3, the asymmetric unit contains two independent
molecules [RuH(CN)(NC-BHNiPr2)2(PCy3)2] (6a and 6b) in a
head-to-tail disposition and presents similar geometrical fea-
tures (Table 1). The structure of 6a is enlarged for clarity
(Fig. 3).
The Ru atom is in a distorted octahedral environment
with the PCy3 ligands in pseudo axial positions bent away
from the isocyanoboranes to reduce steric repulsion (P–Ru–P:
156.151(4)° (6a), 159.151(4)° (6b)). The coordination sites in
the equatorial plane of the ruthenium atom are occupied by
one hydride and three coplanar carbon atoms with the cyano
ligand cis to the hydride. The Ru–C (6a: 2.088(4); 6b: 2.088(4))
and the terminal C–N bond distances (6a: 1.108(5) Å; 6b: 1.121(5)
Å) are comparable to those reported in monomeric Ru(II)
[CpRuL2(CN)] complexes.26–28 The structure is almost collinear
through the B1–N1–C1–Ru1 linkage (B1–N1–C1: 169.1(4)° (6a);
172.7(4)° (6b); N1–C1–Ru1: 173.4(4)° (6a); 174.9(3)° (6b)) cis to
the cyano ligand. This geometrical feature is in favour of sp
hybridization for both N1 and C1. On the contrary, the B2–N3–
C8–Ru1 linkage trans to the cyano ligand reveals a substantial
deviation from linearity at the N3 nitrogen atom (B2–N3–C8:
155.4(4) (6a); 155.2(4) (6b); N3–C8–Ru1 178.2(3) (6a); 177.8(4)
(6b)). A shortening of the Ru1–C8 bond (6a: 1.920(4); 6b:
1.925(4)) accompanies this angular variation, when compared
to the near-linear B1–N1–C1–Ru1 group (Ru1–C1: 1.972(4) (6a);
1.964(4) (6b)). The N3–C8 (6a: 1.184(5); 6b: 1.186(5)) and N1–
C1 (6a: 1.178(5); 6b: 1.173(5)) bond lengths are however
similar, and are set at the upper limit for a coordinated iso-
cyano CN group when compared with those in the only two
reported crystal structures R2R1BNCCr(CO)5 (R2R1B = C4H4N(Et)B
(NC = 1.153(4) Å),14 ((Me3Si)2CH)2B (NC = 1.159(5) Å 13) and
Ru(II) isocyanide complexes (NC ∼ 1.15–1.16 Å).29–32 They both
exhibit a partial C–N triple bond character. The isocyano
carbon ruthenium distances Ru1–C1 and Ru1–C8 are shorter
than the sum of the single-bond covalent radii (2.00 Å),33 thus
suggesting a partially double bond character34–39 as a result of
the metal-to-ligand π-back bonding that takes place more effec-
tively towards the isocyanoborane trans to the cyano group and
involving a deviation from linearity of the CN–B axis at the N
atom. The nitrogen boron distances in 6a/6b (1.335 < NB <
Fig. 3 X-ray crystal structure of 6.
This journal is © The Royal Society of Chemistry 2012
Dalton Trans.

View Article Online
Paper
Dalton Transactions
1.495 Å) are in the range of values observed for amino substi- internally to residual protio-solvent, while 31P are relative to
tuted trigonal-planar boron groups.14,20,40–45 85% H3PO4, and 11B are relative to BF3·OEt2 external refer-
The title compound was optimized by DFT (B3PW91) calcu- ences. Chemical shifts are quoted in δ (ppm) and coupling
lations (6′). The cyano C–N and the Ru–P distances are com- constants in Hertz. The following abbreviations are used: br,
puted slightly too long but the other geometrical parameters broad; s, singlet; d, doublet; t, triplet; m, multiplet. Elemental
are in good agreement with the X-ray data (see Table 1), and analyses were performed by the ‘in house’ service of the Labor-
more importantly, the hydride location by X-ray diffraction in atoire de Chimie de Coordination, Toulouse.
6a/6b, which can always be subjected to controversy, was con-
SYNTHESIS OF DIISOPROPYLAMINE-(CYANO)BORANE (1). NaBH3CN
firmed by the DFT optimization18,19,46,47 of 6′ with the Ru–H (2.69 g, 41.5 mmol) was suspended in Et2O (60 mL), cooled to
bond computed to be 1.642 Å (Ru–H = 1.69(4) Å (6a), 1.56(6) Å 0 °C and a 1.0 M ethereal HCl solution (42 mL, 42 mmol) was
(6b)). The isocyanoborane trans to the hydride is computed added dropwise (ca. 1 h) with stirring. After warming up to
linear (C1–N1–B1: 179.99° (6′) vs. 169.1(4)° (6a), 172.7(4)° (6b)) room temperature, the solution was refluxed for 1 h, cooled
and the deviation from linearity in the one cis to the hydride is again, and filtered. Diisopropylamine (6.2 mL, 42.8 mmol) was
well reproduced (C8–N3–B2: 159.96° (6′) vs. 155.4(4)° (6a), added to the supernatant and the resulting solution refluxed
155.2(4)° (6b)). The small angular variations in 6′ when com- for 12 h. After filtration and aqueous work-up, the ethereal
pared with 6a/6b probably result from too long Ru–P distances, phase was dried over MgSO4, filtered and evaporated to
thus affecting the steric repulsions.
dryness. The resulting white powder was crystallized in ether
at 0 °C affording 1 as a colourless solid (1.63 g, 28% yield). H
1
NMR (400.13 MHz, C6D6) δ 5.42 (br s, 1 H, NH), 2.89 (heptd,
3
i
1
3JCHCH = 6.6 Hz, JCHNH = 3.7 Hz, 2 H, CH Pr), 2.21 (qd, JBH
=
Conclusions
3
3
103 Hz, JCHNH = 2.5 Hz, 2 H, BH2), 1.00 (d, JHH = 6.6 Hz, 12
In this study, we have shown that the reaction of [RuH2(η2- H, CH3 iPr). 11B NMR (128.38 MHz, C6D6) δ −23.8 (t, 1JBH = 103
H2)2(PCy3)2] (3) with an excess diisopropylamino(cyano)borane Hz, BH2). 13C{1H} NMR (100.62 MHz, CDCl3) δ 136.64 (m, CN),
i
iPr2NBH(CN) (2) led to the formation of the hydrido cyano bis 52.18 (s, CH Pr), 20.21, 18.90 (s, CH3 iPr). IR (cm−1) ν(BH)
(diisopropylamino(isocyano)borane) ruthenium complex [RuH- 2447, 2414; ν(CN) 2198. Anal. Calc for C7H17BN2: C, 60.04; H,
(CN)(CN-BHNiPr2)2(PCy3)2] (6) as the major compound. 6 was 12.24; N, 20.00. Found: C, 60.10; H, 10.80; N, 20.00.
fully characterized by multinuclear NMR spectroscopy and
SYNTHESIS
OF
DIISOPROPYLAMINO(CYANO)BORANE
i
(2). Me3SiCN
single-crystal X-ray diffraction. This reaction occurred via the (2.11 mL, 16.8 mmol) was added to neat Pr2NBHCl (2.48 g,
intermediacy of [RuH(CN)(H2BNiPr2)(PCy3)2] (5), a compound 16.8 mmol) and the mixture was stirred for 24 h at room temp-
formulated as a bis(σ-B–H) species on the basis of NMR data. erature. Me3SiCl was then removed at room temperature under
In the presence of a large excess of 2, complex 5 was not reduced pressure (30 mbar) and 2 was purified by trap-to-trap
observed in the reaction medium. The formation of 6 is likely distillation and isolated as a colourless liquid (1.96 g, 85%
1
1
resulting from diisopropylaminoborane displacement at ruthe- yield). H NMR (300.13 MHz, C6D6) δ 3.98 (q, JBH = 143 Hz, 1
nium and BCN linkage isomerisation in 2.
3
i
H, HB), 3.87, 2.80 (hept, JHH = 6.7 Hz, 1 H, CH Pr), 0.81, 0.78
3
(d, JHH = 6.7 Hz, 6 H, CH3 iPr). 11B NMR (96.29 MHz, C6D6) δ
24.7 (d, 1JBH = 143 Hz, BH). 13C{1H} NMR (100.62 MHz, C6D6) δ
1
i
125.30 (q, JCB = 98 Hz, BCN), 54.08, 48.79 (s, CH Pr), 26.13,
22.53 (s, CH3 iPr). IR (cm−1) ν(BH) = 2553; ν(CN) = 2208.
[RuH(CN)(H2BNiPr2)(PCy3)2] (5). 2 (1.5 equiv., 0.058 mmol)
Experimental
Materials and methods
All experiments were performed under an atmosphere of dry in C6D6 (1.5 mL) was added to a C6D6 solution (0.5 mL) of 3
argon using standard Schlenk and glove box techniques. (25.8 mg, 0.039 mmol). The solution was stirred for 3 h at
Unless stated all chemicals were purchased from Aldrich and room temperature prior to NMR analysis. Complex 5 was not
used without further purification. Diisopropylaminoborane,48 isolated from the solution containing 4, 5 and 6 in a 1 : 1 : 1
1
diisopropylaminochloroborane,19 [RuH2(η2-H2)2(PCy3)2]49 were ratio. Selected NMR data: H NMR (400.13 MHz, C6D6) δ 3.76,
3
i
3
prepared according to a literature procedure. THF was freshly 2.95 (sept, JHH = 6.5 Hz, 1 H, CH Pr), 1.13, 1.07 (d, JHH
=
distilled under argon from Na/benzophenone. All other sol- 6.7 Hz, 6 H, CH3 iPr), −4.10 (bs, 1 H, RuHB (cis to CN)), −11.60
2
3
vents were purified and dried through an activated alumina (td, JHP = 21 Hz, JHH = 6 Hz, 1 H, RuH), −11.79 (br, 1 H,
purification system (MBraun SPS-800). NMR solvents were RuHB (trans to CN)). 31P{1H} NMR (162 MHz, C6D6) δ 61.3 (s,
dried using appropriate methods and degassed prior to use. PCy3). 13C{1H} NMR (100 MHz, C6D6) δ 141.73 (t, JCP
=
2
i
NMR samples of sensitive compounds were prepared under an 17.5 Hz, RuCN), 51.08, 46.14 (s, CH Pr), 25.57, 22.90 (14 (s,
argon atmosphere. Nuclear magnetic resonance spectra were CH3 iPr)). 11B{1H} NMR (128.38 MHz, C6D6) δ 29 (br, BH).
recorded on Bruker AV 300, 400 or 500 spectrometers operating
SYNTHESIS OF [RuH(CN)(CNBHNiPr2)2(PCy3)2] (6). A pentane
at 300.13, 400.13 or 500.33 MHz, respectively for 1H, 121.5, 162 solution (0.5 mL) of 2 (0.1 mmol, 3 equiv.) was added to a
or 202.5 MHz, respectively for 31P, 75.48 or 100.62 MHz, stirred suspension of [RuH2(η2-H2)2(PCy3)2] (3) (23 mg,
respectively for 13C and 96.29 or 128.38 MHz, respectively for 0.03 mmol) in pentane (3 mL). The stirring was stopped and
11B. 1H and 13C chemical shifts are reported in ppm referenced after 24 h without stirring, colourless crystals of 6 (6.1 mg,
Dalton Trans.
This journal is © The Royal Society of Chemistry 2012

View Article Online
Dalton Transactions
Paper
21% yield) could be isolated from the solution. 1H NMR
(400.13 MHz, C6D6) δ 4.55, 4.17 (sept, JHH = 6.6 Hz, 1 H, CH
Acknowledgements
3
3
iPr), 4.46 and 4.38 (br, 1 H, BH), 2.97 and 2.86 (sept, JHH
=
We thank the CNRS and the ANR for support through the
i
6.8 Hz, 1 H, CH Pr), 1.30–2.70 (m, 66 H, PCy3), 1.13 and 1.01 ReBAB ANR-11-BS07-0015 program. Johnson Matthey is grate-
(d, 3JHH = 6.8 Hz, 6 H, CH3 iPr), 1.05 and 0.97 (d, 3JHH = 6.6 Hz, fully acknowledged for a generous loan of RuCl3·nH2O.
6 H, CH3 iPr), −7.56 (t, JHP = 22.7 Hz, 1 H, RuH). 11B NMR
2
(128.38 MHz, C6D6) δ 22.6 (br, BH). 31P{1H} NMR (162 MHz,
C6D6) δ 56.40 (s, PCy3). 13C{1H} NMR (100 MHz, C6D6) δ 196.55
(t, 2JCP = 12 Hz, BNCRu), 195.88 (t, 2JCP = 7 Hz, BNCRu), 141.27
2
(t, JCP = 15 Hz, RuCN), 49.44, 49.02, 45.56 and 45.45 (s, CH
Notes and references
iPr), 37.23 (m), 30.30, 28.85 (m), 27.86 (PCy3), 26.97, 26.85,
22.65, 22.56 (s, CH3 iPr). IR (cm−1): 2103 (w, νCN); 2053 and
1971 (vs, RuH(CN)(CNB) coupled modes), 1899 (w, νRuH).
Anal. Calc for C51H97B2N5P2Ru: C, 63.48; H, 10.13; N, 7.26.
Found: C, 64.52; H, 10.37; N, 6.33.
1 A. Dömling, Chem. Rev., 2005, 106, 17–89.
2 V. Nenajdenko, Isocyanide Chemistry. Applications in Syn-
thesis and Material Science, Wiley-VCH, 2012.
3 R. A. Michelin, A. J. L. Pombeiro and M. F. C. Guedes da
Silva, Coord. Chem. Rev., 2001, 218, 75–112.
4 A. J. L. Pombeiro, M. F. C. Guedes da Silva and
R. A. Michelin, Coord. Chem. Rev., 2001, 218, 43–74.
5 D. B. Beach, R. Bertoncello, G. Granozzi and W. L. Jolly,
Organometallics, 1985, 4, 311–316.
6 I. P. Csonka, L. Szepes and A. Modelli, J. Mass Spectrom.,
2004, 39, 1456–1466.
7 W. P. Fehlhammer and M. Fritz, Chem. Rev., 1993, 93,
1243–1280.
8 F. Lavigne, E. Maerten, G. Alcaraz, N. Saffon-Merceron,
C. Acosta-Silva, V. Branchadell and A. Baceiredo, J. Am.
Chem. Soc., 2010, 132, 8864–8865.
X-ray diffraction analyses
Data were collected at low temperature (110 K) on a Bruker
Kappa Apex II diffractometer50 using a graphite-monochro-
mated Mo-Kα radiation (λ = 0.71073 Å) and equipped with an
Oxford Cryosystems Cryostream Cooler device. The structure
was solved by the direct method using SIR92,51 and refined by
means of least-squares procedures on an F2 with SHELXL9752
(a program included in the software’s package WinGX version
1.63).53 The atomic scattering factors were taken from Inter-
national Tables for X-ray Crystallography.54 Except for Hy1 and
Hy2, all hydrogen atoms were placed geometrically, and
refined by using a riding model. All non-hydrogen atoms were
9 A. Pelter, B. Singaram and J. W. Wilson, Tetrahedron Lett.,
1983, 24, 631–634.
anisotropically refined, and in the last cycles of refinement a 10 M. P. Cooke, J. Org. Chem., 1994, 59, 2930–2931.
weighting scheme was used, where weights are calculated from 11 A. Pelter, Pure Appl. Chem., 1994, 66, 223–233.
the following formula: w = 1/[σ2(Fo2) + (aP)2 + bP] where P = 12 M. Höfler and H. Löwenich, J. Organomet. Chem., 1982,
(Fo2 + 2Fc2)/3. It was not possible to resolve diffuse electron-
226, 229–237.
density residuals (enclosed solvent molecule). Treatment with 13 G. Beck, M. F. Lappert and P. B. Hitchcock, J. Organomet.
the SQUEEZE facility from PLATON55 resulted in a smooth
Chem., 1994, 468, 143–148.
refinement. Since a few low order reflections are missing from 14 A. J. V. Marwitz, S. P. McClintock, L. N. Zakharov and
the data set, the electron count will be underestimated. Thus, S.-Y. Liu, Chem. Commun., 2010, 46, 779–781.
the values given for D(calc), F(000) and the molecular weight 15 The isomerization upon coordination of the BCN linkage
are only valid for the ordered part of the structure. Drawing of
molecules was performed with the program ORTEP3256 with
30% probability displacement ellipsoids for non-hydrogen
has been also reported by reaction of (Me2N)2B-CN with
Ni(CO)4 and Fe(CO)5. See: H. Nöth and R. Geltinger, in
R. Geltinger, Dissertation, Universität München, 1974.
atoms. Crystal data of 2 are available as ESI† (CCDC number 16 G. Alcaraz and S. Sabo-Etienne, Coord. Chem. Rev., 2008,
894081).
252, 2395–2409.
17 G. Alcaraz, M. Grellier and S. Sabo-Etienne, Acc. Chem. Res.,
2009, 42, 1640–1649.
Computational details
18 G. Alcaraz, A. B. Chaplin, C. J. Stevens, E. Clot, L. Vendier,
A. S. Weller and S. Sabo-Etienne, Organometallics, 2010, 29,
5591–5595.
All the calculations have been performed with the Gaussian 09
package at the B3PW91 level of hybrid density functional
theory.57–59 For the optimization of geometry, the ruthenium 19 Y. Gloaguen, G. Alcaraz, A.-F. Pécharman, E. Clot,
atom was represented by the relativistic effective core potential
L. Vendier and S. Sabo-Etienne, Angew. Chem., Int. Ed.,
2009, 48, 2964–2968.
(RECP) from the Stuttgart group and the associated basis
sets,60 augmented by an f polarization function.61 The phos- 20 Y. Gloaguen, G. Alcaraz, A. S. Petit, E. Clot, Y. Coppel,
phorus atom was represented by RECP from the Stuttgart
group and the associated basis set,62 augmented by a d polar-
L. Vendier and S. Sabo-Etienne, J. Am. Chem. Soc., 2011,
133, 17232–17238.
ization function.63 The remaining atoms (C, H, N, B) were rep- 21 B. F. Spielvogel, R. F. Bratton and C. G. Moreland, J. Am.
resented by a 6-31G(d,p) basis set.
Chem. Soc., 1972, 94, 8597–8598.
This journal is © The Royal Society of Chemistry 2012
Dalton Trans.

View Article Online
Paper
Dalton Transactions
22 M. P. Kaushik, M. R. M. D. Charandabi, M. L. Ettel, 42 D. T. Carey, F. S. Mair, R. G. Pritchard, J. E. Warren and
T. J. Lofthouse and K. W. Morse, Inorg. Chem., 1989, 28,
897–899.
23 M. Suginome, A. Yamamoto and Y. Ito, Chem. Commun.,
2002, 1392–1393.
24 J. N. Coalter, J. C. Huffman and K. G. Caulton, Organo-
metallics, 2000, 19, 3569–3578.
25 G. Bénac-Lestrille, U. Helmstedt, L. Vendier, G. Alcaraz,
R. J. Woods, Dalton Trans., 2003, 3792–3798.
43 Y. Segawa, Y. Suzuki, M. Yamashita and K. Nozaki, J. Am.
Chem. Soc., 2008, 130, 16069–16079.
44 Y. Segawa, M. Yamashita and K. Nozaki, J. Am. Chem. Soc.,
2009, 131, 9201–9203.
45 H. Nöth and S. Weber, Chem. Ber., 1984, 117, 2504–
2509.
E. Clot and S. Sabo-Etienne, Inorg. Chem., 2011, 50, 11039– 46 G. Alcaraz, E. Clot, U. Helmstedt, L. Vendier and S. Sabo-
11045. Etienne, J. Am. Chem. Soc., 2007, 129, 8704–8705.
26 K. Urtel, A. Frick, G. Huttner, L. Zsolnai, P. Kircher, 47 G. Alcaraz, L. Vendier, E. Clot and S. Sabo-Etienne, Angew.
P. Rutsch, E. Kaifer and A. Jacobi, Eur. J. Inorg. Chem.,
2000, 33–50.
27 C. Ornelas, C. Gandum, J. Mesquita, J. Rodrigues,
M. Helena Garcia, N. Lopes, M. Paula Robalo, K. Nättinen
and K. Rissanen, Inorg. Chim. Acta, 2005, 358, 2482–2488.
28 M. Serrano Ruiz, A. Romerosa, B. Sierra-Martin and
Chem., Int. Ed., 2010, 49, 918–920.
48 L. Euzenat, D. Horhant, Y. Ribourdouille, C. Duriez,
G. Alcaraz and M. Vaultier, Chem. Commun., 2003, 2280–
2281.
49 A. F. Borowski, S. Sabo-Etienne, M. L. Christ, B. Donnadieu
and B. Chaudret, Organometallics, 1996, 15, 1427–1434.
A. Fernandez-Barbero, Angew. Chem., Int. Ed., 2008, 47, 50 Bruker, APEX2 and SAINT, Bruker AXS Inc, Madison,
8665–8669. Wisconsin, USA, 2004.
29 V. Cadierno, P. Crochet, J. Díez, S. E. García-Garrido and 51 A. Altomare, G. Cascarano, C. Giacovazzo and
J. Gimeno, Organometallics, 2004, 23, 4836–4845. A. Guagliardi, J. Appl. Crystallogr., 1993, 26, 343–350.
30 E. Lindner, S. Pautz, R. Fawzi and M. Steimann, Organo- 52 G. M. Sheldrick, Institut für Anorganische Chemie der Uni-
metallics, 1998, 17, 3006–3014.
31 J. P. Lee, Z. Ke, M. A. Ramírez, T. B. Gunnoe, T. R. Cundari,
versität, Tammanstrasse 4, D-3400 Göttingen, Germany,
1998.
P. D. Boyle and J. L. Petersen, Organometallics, 2009, 28, 53 L. Farrugia, J. Appl. Crystallogr., 1999, 32, 837–838.
1758–1775.
54 International Tables for X-ray Crystallography, Kynoch
Press, Birmingham, England, 1974.
55 P. v. d. Sluis and A. L. Spek, Acta Crystallogr., Sect. A:
Fundam. Crystallogr., 1990, 46, 194–201.
32 Y. Yamamoto, R. Satoh and T. Tanase, Dalton Trans., 1995,
307–311.
33 P. Pyykkö and M. Atsumi, Chem.–Eur. J., 2009, 15, 186–197.
34 P. Pyykkö and M. Atsumi, Chem.–Eur. J., 2009, 15, 12770– 56 L. J. Farrugia, J. Appl. Crystallogr., 1997, 30, 565.
12779.
57 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria,
M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone,
B. Mennucci and G. A. Petersson, et al. GAUSSIAN 09
(Revision B1), Wallingford CT, 2009.
35 V. M. Ho, L. A. Watson, J. C. Huffman and K. G. Caulton,
New J. Chem., 2003, 27, 1446–1450.
36 W. Weng, S. Parkin and O. V. Ozerov, Organometallics,
2006, 25, 5345–5354.
58 A. D. Becke, J. Chem. Phys., 1993, 98, 5648–5652.
37 J. N. Coalter III, J. C. Bollinger, J. C. Huffman, U. Werner- 59 J. P. Perdew and Y. Wang, Phys. Rev. B: Condens. Matter,
Zwanziger, K. G. Caulton, E. R. Davidson, H. Gerard,
E. Clot and O. Eisenstein, New J. Chem., 2000, 24, 9–26.
38 G. Ferrando-Miguel, J. N. Coalter III, H. Gerard,
1992, 45, 13244–13249.
60 D. Andrae, U. Häußermann, M. Dolg, H. Stoll and
H. Preuß, Theor. Chim. Acta, 1990, 77, 123–141.
J. C. Huffman, O. Eisenstein and K. G. Caulton, New 61 A. W. Ehlers, M. Böhme, S. Dapprich, A. Gobbi,
J. Chem., 2002, 26, 687–700.
39 R. F. Winter and T. Scheiring, Z. Anorg. Allg. Chem., 2000,
626, 1196–1204.
A. Höllwarth, V. Jonas, K. F. Köhler, R. Stegmann,
A. Veldkamp and G. Frenking, Chem. Phys. Lett., 1993, 208,
111–114.
40 J. Haberecht, A. Krummland, F. Breher, B. Gebhardt, 62 A. Bergner, M. Dolg, W. Küchle, H. Stoll and H. Preuß, Mol.
H. Ruegger, R. Nesper and H. Grutzmacher, Dalton Trans.,
2003, 2126–2132.
41 A. Goswami, H. Pritzkow, F. Rominger and W. Siebert,
Eur. J. Inorg. Chem., 2004, 2004, 4223–4231.
Phys., 1993, 80, 1431–1441.
63 A. Höllwarth, M. Böhme, S. Dapprich, A. W. Ehlers,
A. Gobbi, V. Jonas, K. F. Köhler, R. Stegmann, A. Veldkamp
and G. Frenking, Chem. Phys. Lett., 1993, 208, 237–240.
Dalton Trans.
This journal is © The Royal Society of Chemistry 2012