Ru(II)-arene complexes with N-substituted 3,4-dihydroquinazoline ligands and catalytic activity for transfer hydrogenation reaction

Article abstract of DOI:10.1016/j.ica.2013.02.005

In this study, N-coordinated 3,4-dihydroquinazoline ruthenium(II) complexes were synthesized by the cleavage reaction of [RuCl₂(p-cymene)] ₂ with N-substituted 3,4-dihydroquinazolines. In addition, the X-ray crystal structure of 2,4,6-trimethylbenzyl substituted 3,4-dihydroquinazoline Ru(II) complex (1a) is reported. Furthermore, the resulting piano-stool complexes were evaluated as transfer hydrogenation catalysts for reduction of acetophenone in the presence of 2-propanol and KOH at 82°C. All the complexes showed good to excellent performance after 1 h in the conversion of acetophenone to alcohol and the reaction rate was found to be sensitive to changes on the N-substituent. Additionally, the most active catalyst 1a was used in transfer hydrogenation of different ketones to investigate the effect of substituents on ketones.

Full text of DOI:10.1016/j.ica.2013.02.005

Accepted Manuscript
Ru(II)-Arene Complexes with N-Substituted 3,4-Dihydroquinazoline Ligands
and Catalytic Activity for Transfer Hydrogenation Reaction
Deniz Mercan, Engin Çetinkaya, Ertan Şahin
PII:
S0020-1693(13)00044-3
http://dx.doi.org/10.1016/j.ica.2013.02.005
ICA 15323
DOI:
Reference:
To appear in:
Inorganica Chimica Acta
Received Date:
Revised Date:
Accepted Date:
26 September 2012
25 January 2013
6 February 2013
Please cite this article as: D. Mercan, E. Çetinkaya, E. Şahin, Ru(II)-Arene Complexes with N-Substituted 3,4-
Dihydroquinazoline Ligands and Catalytic Activity for Transfer Hydrogenation Reaction, Inorganica Chimica
Acta (2013), doi: http://dx.doi.org/10.1016/j.ica.2013.02.005
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Ru(II)-Arene Complexes with N-Substituted 3,4-Dihydroquinazoline Ligands
and Catalytic Activity for Transfer Hydrogenation Reaction
a
,a
b
Deniz Mercan , Engin Çetinkaya* , Ertan Şahin
a
Ege University, Faculty of Science, Department of Chemistry, 35100 Bornova-Izmir, Turkey
Atatürk University, Faculty of Science, Department of Chemistry, 25240 Erzurum, Turkey
b
ABSTRACT
In this study, N-coordinated 3,4-dihydroquinazoline ruthenium(II) complexes were synthesized by
2 2
the cleavage reaction of [RuCl (p-cymene)] with N-substituted 3,4-dihydroquinazolines. In addition,
the X-ray crystal structure of 2,4,6-trimethylbenzyl substituted 3,4-dihydroquinazoline Ru(II)
complex (1a) is reported. Furthermore, the resulting piano-stool complexes were evaluated as transfer
hydrogenation catalysts for reduction of acetophenone in the presence of 2-propanol and KOH at
o
8
2 C. All the complexes showed good to excellent performance after 1h in the conversion of
acetophenone to alcohol and the reaction rate was found to be sensitive to changes on the N-
substituent. Additionally, the most active catalyst 1a was used in transfer hydrogenation of different
ketones to investigate the effect of substituents on ketones.
Keywords: 3,4-Dihydroquinazoline; ruthenium(II) complexes; transfer hydrogenation reaction
1. Introduction
6
Ru(II)-arene complexes of the type [(η - arene)RuCl
2 2
] are very versatile electrophiles
since they can be used to introduce a variety of ligands with CNHC-, P-, O- or S- donor
[1-6]
atoms.
The resulting monomeric complexes, in neutral, mono- or dicationic forms, can be
used as catalysts for a number of organic transformations or as biologically active
[
7-9]
compounds. The Ru(II) complexes with ligands bearing N-donor atoms are attracting
interest of researchers due to their potential to promote the catalytic reaction of organic
[
10-12]
6
compounds.
In this context, (η -arene)Ru(II) complexes containing N-bonded
heterocycles, such as N-alkybenzazole, N-alkylimidazoline and N-alkyl-1,4,5,6-
tetrahydropyrimidine were prepared and used successfully as catalysts for transfer
hydrogenation or for the cyclization of (Z)-3-methylpent-2-en-4-yn-1-ol into 2,3-
[13-19]
dimethylfuran.
*Corresponding author: E-mail:engin.cetinkaya@ege.edu.tr
Tel:+90 232 3112366
Fax:+90 232 3888264 (E. Çetinkaya)
1

However the development of new ligands is still of considerable importance, in order to find
more efficient ruthenium catalysts. Recent studies showed that complexes derived from six-
membered heterocyclic rings such as tetrahydropyrimidine exhibit superior activity as
[
19]
compared with five-membered analogues
and that the substitution pattern on the
heterocyclic ring is also an important factor to affect the catalytic activity. Nevertheless, six-
membered systems and their metal complexes have not been studied in detail. It is worth
noting that although the quinazoline skeleton is a common structural motif among
heterocycles and has been found to show remarkable biological activities and applications as
[
20-27]
pharmaceutical agents,
quinazoline containing complexes are rarely found in the
[28-32]
literature.
Therefore, it seems of interest to examine the influence of benzene annulation
at the 5,6-position of the reduced pyrimidines having alkyl- and aryl- substituents at the
nitrogen atom. Thus, we wish to report here the synthesis and transfer hydrogenation activity
of N-coordinated quinazoline Ru(II)-(arene) complexes.
2. Experimental
2
.1. General
Unless otherwise specified all reactions were performed under argon using standard Schlenk
techniques. Starting compounds and reagents were purchased from Merck (4-
methylbenzaldehyde, 4-dimethylaminobenzaldehyde, sodium borohydride) Sigma-Aldrich (2-
aminobenzylamine) Alfa Aesar (2,4,6-trimethylbenzaldehyde, 2,4,6-trimethoxybenzaldehyde,
3,4,5-trimethoxybenzaldehyde, 4-isopropylbenzaldehyde, 1-methylimidazole, p-anisidine)
and Acros Organics (p-toluidine, p-anisaldehyde, 1,2-dimethylimidazole, N,N-
dimethylformamide dimetyhl acetal) and used as received. Solvents like dichloromethane,
ethanol, diethyl ether, toluene were obtained from Riedel-de Haën, Merck and J.T. Baker. The
[
33]
[34]
[35]
[36]
[37-38]
[39-47]
synthesis of Ab+Bb,
Ad+Bd,
Ae+Be,
Cb,
Ce,
E , F
have been
reported previously. The spectroscopic data of these compounds were given in supplementary
[48] 1
material. [RuCl
2
(p-cymene)]
2
was prepared by following a literature protocol.
H NMR
1
3
and C NMR spectra were taken with a Varian AS 400 Mercury instrument operating at
1
13
3
1 3
99.88 MHz ( H), 100.56 ( C). As solvents d -CDCl was employed. Chemical shifts (δ) are
given in ppm relative to TMS; coupling constants (J) in Hz. The multiplicities of the signals
are abbreviated as follows: s, singlet; d, doublet; t, triplet; q, quartet; hept, heptet; m,
multiplet. Elemental analysis of samples were done using on a LECO
CHNS model 932 elemental analyzer. FTIR Spectra were recorded on a Perkin Elmer
Spectrum 100 series. MS analyses were performed using Bruker HCT Ultra Mass
2

Spectrometry (ESI) Agilent 1200 Capillary HPLC. Melting points were recorded with a
Gallenkamp electrothermal melting point apparatus.
2
.2. X-ray crystallography
For the crystal structure determination, the single-crystal of the Ru (II) complex 1a was
used for data collection on a four-circle Rigaku R-AXIS RAPID-S diffractometer (equipped
with a two-dimensional area IP detector). The graphite-monochromatized Mo K radiation
λ=0.71073 Å) and oscillation scans technique with Δω=5˚ for one image were used for data
collection. The lattice parameters were determined by the least-squares methods on the basis
α
(
2
2
of all reflections with F >2σ(F ). H atoms were positioned geometrically and refined using a
riding model. Integration of the intensities, correction for Lorentz and polarization effects and
[49]
cell refinement was performed using CrystalClear (Rigaku/MSC Inc., 2005) software. The
[50]
structure was solved by direct methods using SHELXS-97
and refined by a full-matrix
[
50]
least-squares procedure using the program SHELXL-97. The final difference Fourier maps
showed no peaks of chemical significance. Details of the crystal parameters, data collection
and refinement are summarized in Table 1.
CCDC-883056 contains the supplementary crystallographic data for complex 1a. These data
can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from
the Cambridge Crystallographic Data Centre.
Table 1
2.3. General procedure for the synthesis of compounds (A+B)
Substituted benzaldehyde derivatives (16.4 mmol) were added to a solution of 2-
aminobenzylamine (16.4 mmol) in methanol (10 mL). The mixture was stirred at room
temperature for 3 h. The light-yellow precipitate was filtered and washed with cold methanol
[
34]
(
Scheme 1).
2.4 General procedure for the synthesis of compounds (C)
The mixture of Aa and Ba (15.9 mmol) was dissolved in methanol (30 mL) and NaBH
4
(31.7 mmol) was added slowly under Ar (Scheme 1). The mixture was stirred for 2 h at room
temperature. After that time the mixture was refluxed for 24 h. Then the solvent was removed
3

and the solid was extracted with CH
the product was washed with Et O.
2 2 2
Cl /H O. The dried organic phase was concentrated and
2
o
1
Ca: (96%). mp 72-74 C, H NMR δ 7.09-7.02, 6.69-6.62 (m, 4H, NH
H, C (CH -2,4,6), 4.68 (s, 2H, NH ), 3.91 (s, 2H, NH CH
CH (CH -2,4,6), 2.34, 2.26 (s, 9H, C -2,4,6). C NMR δ 147.2, 130.1,
28.6, 124.3 117.8, 115.9 (NH CH NH), 137.1, 136.8, 133.7, 129.2 (CH (CH
,4,6), 53.8( CH (CH -2,4,6), 47.3 (NH CH NH), 21.1, 19.7 (C (CH -2,4,6).
(254.37): C 80.27, H 8.72, N 11.01 Found: C 80.23, H 8.74, N
2
C
6
H
4
CH
2
NH), 6.85 (s,
2
6
H
2
3
)
3
2
2
C
6
H
4
2
NH), 3.76 (s, 2H,
1
3
2
C
6
H
2
3
)
3
6 2 3 3
H (CH )
1
2
2
C
6
H
4
2
C
2 6
H
2
3 3
) -
2
C
6
H
2
3
)
3
2
6
C H
4
2
6
H
2
3 3
)
Anal. Calcd (%) for C17
22 2
H N
1
1.03.
1
Cc: (87%). Liquid, H NMR δ 7.23-7.15 (m, 4H, C
.01 (d, J 7.2 Hz, 1H), 6.68-6.63 (m, 2H) (NH CH
NH CH NH) 3.74 (s, 2H, CH (CH(CH
(CH(CH )-4), 1,24 (d, J 6.7 Hz, 6H, C
28.6, 124.2, 117.9, 115.9 (NH CH NH), 147.9, 137.9, 128.4, 126.7 (C
), 53.3, (CH (CH(CH )-4), 52.7 (NH CH NH), 34.1 (C (CH(CH
(CH(CH )-4). Anal. Calcd (%) for C17 (254.37): C 80.27, H 8.72, N 11.01
6
H
4
(CH(CH
NH)], 4.66 (s, 2H, NH
)-4), 2.89 (hept, J 6.7 Hz, 1H,
3
)
2
)-4), [7.09-7.05 (m, 1H)
7
2
C
6
H
4
2
2
2
), 3.81 (s, 2H,
2
C
6
H
4
2
2
C
6
H
4
3
)
13
C
6
H
4
3
)
2
6
H
4
(CH(CH
3
)
2
)-4). C NMR δ 147.2, 130.2,
(CH(CH )-
)-4), 24.3
1
4
2
C
6
H
4
2
6
H
4
3 2
)
2
C
6
H
4
3
)
2
2
C
6
H
4
2
6
H
4
3 2
)
(C
6
H
4
3
)
2
22 2
H N
Found: C 80.22, H 8.75, N 11.02.
1
Cd: (88%). Liquid, H NMR δ 7.07, 6.61 (d, J 8.8 Hz, 4H, C
6
H
4
(N(CH
CH NH)], 4.60 (s, 2H, NH
(N(CH )-4), 2.85 (s, 6H,
)-4). C NMR δ 147.3, 130.2, 128.6, 124.4, 117.9, 115.9, (NH CH NH),
50.1, 129.3, 128.5, 112.9 (C (N(CH )-4), 53.0 (CH (N(CH )-4), 52.5
NH CH NH), 41.0 (C (N(CH )-4). Anal. Calcd (%) for C16 (255.36): C
5.26, H 8.29, N 16.45 Found: C 75.29, H 8.28, N 16.43.
3
)
2
)-4), [6.97 (t, J 1.6
Hz, 1H), 6.91 (d, J 7.6 Hz, 1H), 6.56-6.52 (m, 2H) (NH
2
C
6
H
4
2
2
),
3
.71(s, 2H, NH CH NH), 3.59 (s, 2H, CH
2
C
6
H
4
2
2
C
6
H
4
3 2
)
13
C
6
H
4
(N(CH
3
)
2
C
2 6
H
4
2
1
6
H
4
3
)
2
2
C
6
H
4
3 2
)
(
2
C
6
H
4
2
6
H
4
3
)
2
21 3
H N
7
o
1
Cf: (81%). mp 68-70 C, H NMR δ [7.05 (t, J 8 Hz, 1H), 6.97-6.95 (m, 1H), 6.63-6.60 (m,
2
2
1
H) (NH
,4,6), 3.82 (s, 2H, NH
47.5, 130.1, 128.2, 124.9, 117.5, 115.7, (NH
(OCH -2,4,6), 55.7, 55.3 (C (OCH -2,4,6), 52.2 (CH
CH NH ). Anal. Calcd (%) for C17 (302.37): C 67.53, H 7.33, N 9.26
2
C
6
H
4
CH
2
NH)], 6.14 (s, 2H, C
CH NH), 3.79 (s, 2H, CH
CH
6 2 3 3 6 2 3 3
H (OCH ) -2,4,6), 3.83, 3.81 (s, 9H, C H (OCH ) -
1
3
2
6
C H
4
2
2
C
6
H
2
(OCH
NH), 160.6, 159.7, 109.4, 90.6
(OCH -2,4,6), 40.9
3 3
) -2,4,6). C NMR δ
2
C
6
H
4
2
(C
6
H
2
3
)
3
6
H
2
3
)
3
2
C
6
H
2
3 3
)
(NH
2
C
6
H
4
2
22 2 3
H N O
Found: C 67.55, H 7.32, N 9.28.
4

o
1
Cg: (70%). mp 68-70 C, H NMR δ [7.06 (d, J 7.6 Hz, 1H), 6.99 (d, J 6.8 Hz, 1H), 6.67-6.62
m, 2H) (NH CH NH)], 6.52 (s, 2H, C (OCH -3,4,5), 3.85, 3.83 (s, 9H,
(OCH -3,4,5), 3.81 (s, 2H, NH CH NH), 3.72 (s, 2H, CH (OCH -3,4,5).
C NMR δ 147.0, 130.3, 128.7, 123.9, 118.0, 115.9 (NH CH NH), 153.5, 137.3, 136.1,
05.3 (C (OCH -3,4,5), 61.1, 56.4 (C (OCH -3,4,5), 53.7 (CH (OCH -3,4,5),
2.4 (NH CH NH) . Anal. Calcd (%) for C17 (302.37): C 67.53, H 7.33, N 9.26
(
C
2 6
H
4
2
6
H
2
3 3
)
C
6
H
2
)
3 3
2
C
6
H
4
2
2
C
6
H
2
3 3
)
1
3
C
2 6
H
4
2
1
5
6
H
2
3
)
3
6
H
2
3
)
3
2
6
C H
2
3 3
)
2
C
6
H
4
2
22 2 3
H N O
Found: C 67.56, H 7.34, N 9.24.
.5 General procedure for the synthesis of compounds (D)
2
The monosubstituted diamine C (11.8 mmol) was heated with Me
2
NCH(OMe)
mmol) on an oil bath for 2 h at 90 C and 1 h at 110 C in order to distill MeOH and Me
formed. Following the completion of the process, volatiles were removed under vacuo and the
residue was crystallized from Et O.
2
(12.9
o
o
2
NH
2
o
1
Da: (82%). mp 147-149 C, H NMR δ [7.13 (t, J 8 Hz, 1H), 7.02 (d, J 7.6 Hz, 1H), 6.95 (t, J
.6 Hz, 1H), 6.77 (d, J 7.2 Hz, 1H) (NC CH N)], 6.97 (s, 1H, NCHN), 6.89 (s, 2H,
(CH -2,4,6), 4.41 (s, 2H, NC CH N), 4.27 (s, 2H, CH
s, 9H, NMR 149.5 (NCHN),
NCC 128.5, 124.8 (NCCHC CHCCH
NCCHC )CHC(CH
CC(CH )CHC(CH [CC(CH )CHC(CH
(CH -2,4,6), -2,4,6), 46.8 (NC
(CH -2,4,6). υ(CN)=1614cm . Anal. Calcd (%) for
(264.36): C 81.78, H 7.62, N 10.60 Found: C 81.52, H 7.75, N 10.73.
7
6
H
4
2
C
6
H
2
3
)
3
6
H
4
2
2
C
6
H
2
(CH
3
)
3
-2,4,6), 2.33, 2.28
142.2, 120.4
1
3
(
(
(
[
(
(
C
6
H
2
(CH
3
)
3
-2,4,6).
C
δ
5
H
4
CCH
2
N)benzylamine
,
2
H
2
2
N)benzylamine, 125.8, 124.7
)]benzyl, 138.0
2
H
2
CHCCH
2
N)benzylamine, 138.2, 127.2 [CC(CH
3
3
)CHC(CH
)CHC(CH
CH N),
3
3
3
)CHC(CH
3
)]benzyl
,
129.8
(CH
(CH
3
3
3
)]benzyl,
C
6
H
2
3
)
3
50.6
(CH
2
C
6
H
2
3
)
3
6
H
4
2
21.2
-1
CH
2
C
6
H
2
3
)
3
-2,4,6), 20.3 (CH
2
C
6
H
2
3
)
3
C
18
H
20
N
2
o
1
Db: (46%). mp 100-102 C, H NMR δ 7.23 (s, 1H, NCHN), 7.18 (s, 4H, CH
2
C
6
H
4
(CH
3
)-4),
[
(
7.14 (t, J 7.2 Hz, 1H), 7.07 (d, J 8 Hz, 1H), 6.96 (t, J 7.6 Hz, 1H), 6.75 (d, J 7.6 Hz, 1H)
NC
6
4
6
6
H
4
2 6 4 2 2 6 4 3
CH N)], 4.38 (s, 2H, NC H CH N), 4.26 (s, 2H, CH C H (CH )-4), 2.35 (s, 3H,
1
3
C
6
H
(CH )-4). C NMR δ 150.3 (NCHN), 141.9, 128.5, 125.9, 124.9, 124.8, 120.6
3
(NC
H
H
4
4
CH
2
N), 138.2, 132.2, 129.8, 127.9 (C )-4), 46.5
6
H
4
(CH
3
)-4), 56.8 (CH
2
C
6
H
4
(CH
3
-
1
(NC
CH
2
N), 21.3 (C (CH )-4). υ(CN)=1617cm . Anal. Calcd (%) for C16H N (236.31):
6
H
4
3
16 2
C 81.32, H 6.82, N 11.85 Found: C 81.20, H 6.89, N 11.90.
o
1
6 4 3 2
Dc: (70%). mp 117-119 C, H NMR δ 7.25-7.22 (m, 4H, C H (CH(CH ) )-4), 7.19 (s, 1H,
NCHN), [7.14 (t, J 7.6 Hz, 1H), 7.07 (d, J 8 Hz, 1H), 6.93-6.97 (m, 1H), 6.76 (d, J 7.6 Hz,
5

1
H) (NC
hept, J 6.7 Hz, 1H, C
NMR δ 150.2 (NCHN), 141.8, 128.5, 125.8, 124.9, 124.8, 120.5 (NC
6
H
4
CH
2
N)], 4.39 (s, 2H, NC
6
H
4
CH
2
N), 4.25 (s, 2H, CH
2
C
6
H
4
(CH(CH
(CH(CH
CH
)-4), 46.6 (NC
3 2
) )-4), 2.91
13
(
6
H
4
(CH(CH
3
)
2
)-4), 1.25 (d, J 6.7 Hz, 6H, C
6
H
4
3
)
2
)-4).
N), 149.2,
CH N),
)-4). υ(CN)=1617cm . Anal. Calcd (%) for
(264.36): C 81.78, H 7.62, N 10.60 Found: C 81.60, H 7.72, N 10.68.
C
6
H
4
2
1
32.5, 128.0, 127.2 (C
6
H
4
(CH(CH
3
)
2
)-4), 56.9 (CH
(CH(CH
C
2 6
H
4
(CH(CH
3
)
2
6
H
4
2
-1
34.1 (C (CH(CH )-4), 24.2 (C
6
H
4
3
)
2
6
H
4
3 2
)
C
18
H
20
N
2
o
1
Dd: (74%). mp 138-140 C, H NMR δ 7.22 (s, 1H, NCHN), 7.15, 6.71 (d, J 8.8 Hz, 4H,
(N(CH )-4), [7.12 (t, J 7.6 Hz, 1H), 7.06 (d, J 8 Hz, 1H), 6.95 (t, J 7.2 Hz, 1H), 6.76 (d,
J 7.6 Hz, 1H) (NC CH N)], 4.38 (s, 2H, NC CH N), 4.20 (s, 2H, CH (N(CH )-
(N(CH )-4). C NMR δ 150.3 (NCHN), 142.1, 128.4, 125.9, 124.8,
CH N), 150.7, 129.2, 122.3, 112.8 (C (N(CH )-4), 56.8,
)-4), 46.3 (NC CH N), 40.7 (C (N(CH )-4). υ(CN)=1614cm . Anal.
(265.35): C 76.95, H 7.22 N, 15.84 Found: C 76.80, H 7.27, N 15.93.
C
6
H
4
3 2
)
6
H
4
2
6
H
4
2
2
6
C H
4
3 2
)
1
3
4
), 2.95 (s, 6H, C
24.7, 120.7 (NC
(N(CH
Calcd (%) for C17
6
H
4
3 2
)
1
6
H
4
2
6
H
4
3 2
)
-
1
(CH
C
2 6
H
4
3
)
2
6
H
4
2
6
H
4
3 2
)
H
19
N
3
o
1
De: (78%). mp 83-85 C, H NMR δ 7.19 (s, 1H, NCHN), 7.17, 6.89 (d, J 2.8 Hz, 4H,
(OCH )-4), [7.12-7.10 (m, 1H), 7.05 (d, J 7.2 Hz, 1H), 6.95-6.93 (m, 1H), 6.73 (d, J 6.8
Hz, 1H) (NC CH N)], 4.34 (s, 2H, NC CH N), 4.19 (s, 2H, CH (OCH )-4), 3.78 (s,
H, C (OCH )-4). C NMR δ 150.2 (NCHN), 141.9, 128.5, 125.9, 124.9, 124.8, 120.6
N), 159.8, 129.3, 127.1, 114.6 (C (OCH )-4), 56.6 (CH (OCH )-4), 46.4
N), 55.5 (C (OCH )-4). υ(CN)=1615cm . Anal. Calcd (%) for C16
C
6
H
4
3
6
H
4
2
6
H
4
2
2
C
6
H
4
3
1
3
3
6
H
4
3
(
(
(
NC
6
H
4
4
CH
2
6
H
4
3
2
C
6
H
4
3
-
1
NC
6
H
CH
2
6
H
4
3
16 2
H N O
252.31): C 76.16, H 6.39, N 11.10 Found: C 76.23, H 6.42, N 11.84.
o
1
Df: (96%). mp 148-150 C, H NMR δ 7.18 (s, 1H, NCHN), [7.05 (t, J 8.8 Hz, 1H), 6.94 (d, J
8
Hz, 1H), 6.86 (t, J 7.2 Hz, 1H), 6.73 (d, J 7.2 Hz, 1H) (NC
(OCH -2,4,6), 4.38 (s, 2H, NC CH N), 4.25 (s, 2H, CH
-2,4,6). C NMR δ 151.2 (NCHN), 142.3, 128.1, 125.7, 124.4,
N), 161.7, 160.1, 103.9, 90.6 (C (OCH -2,4,6), 55.8, 55.4
-2,4,6), 46.2 (CH (OCH -2,4,6), 44.7 (NC CH
(312.36): C 69.21, H 6.45, N 8.97 Found: C 69.40, H 6.46, N
6
H
4
CH
2
N)], 6.09 (s, 2H,
C
6
H
2
3
)
3
6
H
4
2
2
C
6
H
2
(OCH
3 3
) -2,4,6), 3.82,
1
3
3
.79 (s, 9H, C
24.1, 121.1 (NC
(OCH
Anal. Calcd (%) for C18
.87.
6
H
2
(OCH
3 3
)
1
6
4
H CH
2
6
H
2
3 3
)
-1
(C
6
H
2
3
)
3
2
C
6
H
2
3
)
3
6
H
4
2
N). υ(CN)=1612cm .
H
20 2 3
N O
8
o
1
Dg: (66%). mp 125-127 C, H NMR δ 7.17 (s, 1H, NCHN), [7.14 (t, J 7.6 Hz, 1H), 7.06 (d, J
7
.6 Hz, 1H), 6.96 (t, J 7.6 Hz, 1H), 6.77 (d, J 7.2 Hz, 1H)(NC
(OCH -3,4,5), 4.41 (s, 2H, NC CH N), 4.22 (s, 2H, CH
.83 (s, 9H, C -3,4,5). C NMR δ 150.2 (NCHN), 141.7, 128.6, 125.9, 125.1,
6
H
4
CH
2
N)], 6.47 (s, 2H,
C
6
H
2
)
3 3
6
H
4
2
2
C
6
H
2
(OCH
3 3
) -3,4,5), 3.85,
1
3
3
6
6 2 3 3
H (OCH )

1
24.9, 120.5 (NC
(OCH -3,4,5), 57.4 (CH
Anal. Calcd (%) for C18 (312.36): C 69.21, H 6.45, N 8.97 Found: C 69.44, H 6.35, N
6
H
4
CH
2
N), 153.9, 138.1, 130.9, 104.9 (C
6
H
2
(OCH
3 3
) -3,4,5), 61.1, 56.5
-1
(C
6
H
2
3
)
3
C
2 6
H
2
(OCH -2,4,6), 46.6 (NC
3
)
3
6
H
4
CH
2
N). υ(CN)=1618cm .
20 2 3
H N O
8
.79.
2.6 General procedure for the synthesis of Ru(II) complexes (1-3)
3
,4-Dihydroquinazoline derivatives (0.76 mmol) were dissolved in dry toluene (10 mL)
and then [RuCl (p-cymene)] (0.38 mmol) was added to the solution. The mixture was
refluxed for 4h under Ar. After that time the solvent was removed under vacuo and red/orange
crystals were obtained by crystallization with CH Cl /Et O. 1-Methylimidazol- and 1,2-
dimethylimidazol Ru(II) complexes were synthesized using the same procedure.
2
2
2
2
2
o
1
1
a: (81%). mp 226-228 C, H NMR δ 7.74 (s, 1H, NCHN), [7.94 (d, J 8.4 Hz, 1H), 7.18 (t, J
.6 Hz, 1H), 7.00 (t, J 7.2 Hz, 1H), 6.78 (d, J 7.6 Hz, 1H) (NC CH N)], 6.93 (s, 2H,
(CH -2,4,6), 5.15, 5.39 (d, J 5.6 Hz, 4H, (CH CHC (CH
CH N), 4.34 (s, 2H, CH (CH -2,4,6), 2.84 (hept, J
7
6
H
4
2
C
6
H
2
3
)
3
3
)
2
6
H
4
3
)-4), 4.49 (s, 2H,
7.1 Hz, 1H,
NC
6
H
4
2
2
C
6
H
2
3 3
)
(
(
(
(
CH
CH
3
3
)
2
2
CHC
6
H
H
4
4
(CH
3
)-4), 2.36, 2.29 (s, 9H,
C
6
H
2
(CH
CHC
CH
(CH
)-4), 22.5 ((CH
(CH )-4). υ(CN)=1622 cm . Anal. Calcd
3 3
) -2,4,6), 2.01 (s, 3H,
1
3
)
CHC
6
(CH
3
)-4), 1.21 (d, J 7.1 Hz, 6H, (CH
3
)
2
6
H
4
(CH
N), 138.9, 138.5, 129.8, 126.6,
)-4), 51.2 (CH (CH
CHC (CH )-4),
3
)-4). C NMR δ 155.3
NCHN), 140.4, 128.2, 126.9, 125.7, 125.5, 120.8 (NC
(CH -2,4,6), 102.9, 96.7, 82.1, 81.9 ((CH CHC
,4,6), 47.7 (NC (CH
1.2, 20.4 (C (CH
6
H
4
2
C
6
H
2
3
)
3
3
)
2
6
H
4
3
2
C
6
H
2
3 3
) -
2
2
6
4
H CH
2
N), 30.6 ((CH
3
)
2
CHC
6
H
4
3
3
)
2
6
H
4
3
-1
6
H
2
3
)
3
-2,4,6), 18.3 ((CH
3
)
2
CHC
6
H
4
3
2 2
(%) for C28H34Cl N Ru (570.56): C 58.94, H 6.01, N 4.92 Found: C 58.90, H 6.05, N 4.97.
o
1
1
1
5
b: (90%). mp 210-212 C, H NMR δ 8.16 (s, 1H, NCHN), [8.07 (d, J 8 Hz, 1H), 7.19 (s,
H), 7.00 (t, J 7.2 Hz, 1H), 6.76 (d, J 7.6 Hz, 1H) (NC CH N)], 7.19 (s, 4H, C (CH )-4),
.49, 5.29 (d, J 5.6 Hz, 4H, (CH CHC (CH )-4), 4.42 (s, 2H, NC CH N), 4.31 (s, 2H,
)-4), 3.03 (hept, J 6.9 Hz, 1H, (CH CHC (CH )-4), 2.22 (s, 3H,
CHC (CH )-4), 1.32 (d, J 6.9 Hz, 6H,
)-4). C NMR δ 155.6 (NCHN), 140.6, 128.3, 126.9, 125.8, 125.7, 120.9
(CH )-4), 102.6, 97.4, 82.7, 81.7
)-4), 46.3 (NC CH N), 30.8
(CH )-4), 21.4 (C (CH )-4), 18.6
Ru (542.51): C
6
H
4
2
6
H
4
3
3
)
2
6
H
4
3
6
H
4
2
CH
2
C
6
H
4
(CH
3
3
)
2
6
H
4
3
C
6
H
4
3
6
3
(CH
CHC
CH
CHC
3
)-4), 2.16 (s, 3H, (CH
3
)
2
6
H
4
3
1
3
(
(
(
(
(
CH
NC
CH
)
2
6
H
4 3
(CH
H
4
2
N), 138.7, 130.8, 129.9, 128.5 (C
(CH )-4), 57.8 (CH (CH
)-4), 22.6 ((CH CHC
6
H
4
3
)
2
)
)
6
H
4
3
2
C
6
H
4
3
6
H
4
2
(CH
(CH
3
3
2
2
CHC
6
6
H
4
4
(CH
(CH
3
3
3
)
2
6
H
4
3
6
H
4
3
-
1
CHC
H
)-4). υ(CN)=1623 cm . Anal. Calcd (%) for C26
H
30Cl
2
N
2
57.56, H 5.57, N 5.16 Found: C 57.51, H 5.62, N 5.19.
7

o
1
1
c: (47%). mp 214-216 C, H NMR δ 8.11 (s, 1H, NCHN), [8.05 (d, J 8 Hz, 1H), 7.17 (t, J
.2 Hz, 1H), 6.98 (t, J 7.6 Hz, 1H), 6.78 (d, J 7.2 Hz, 1H) (NC CH N)], 7.22 (s, 4H,
(CH(CH )-4), 5.49, 5.27 (d, J 5.6 Hz, 4H, (CH CHC (CH )-4), 4.42 (s, 2H,
CH N), 4.23 (s, 2H, CH (CH(CH )-4), 3.02 (hept, J 7.0 Hz, 1H,
)-4), 2.90 (hept, J 7.0 Hz, 1H, C (CH(CH )-4), 2.19 (s, 3H,
)-4), 1.30 (d, J 7.0 Hz, 6H, (CH CHC (CH )-4), 1.25 (d, J 7.0 Hz,
)-4). C NMR δ 155.6 (NCHN), 140.6, 128.1, 126.9, 125.9, 125.6, 120.9
N), 149.6, 131.3, 128.6, 127.3 (C (CH(CH )-4), 102.6, 97.4, 82.7, 81.7
(CH(CH )-4), 46.4 (NC CH N), 34.1
(CH )-4), 24.1 (C (CH(CH ) -4), 22.6
(CH )-4). υ(CN)=1622 cm Anal. Calcd (%) for
7
6
H
4
2
C
6
H
4
3
)
2
3
)
2
6
H
4
3
NC
6
H
4
2
2
C
6
H
4
3 2
)
(
(
CH
CH
3
3
)
2
2
CHC
6
H
H
4
4
(CH
3
6
H
4
3 2
)
)
CHC
6
(CH
3
3
)
2
6
H
4
3
1
3
6H, C
6
H
4
(CH(CH
CH
CHC
(CH(CH
CHC
3 2
)
(
(
(
(
NC
CH
6
H
4
2
6
H
4
3 2
)
3
)
2
6
H
4
3
(CH
3
)-4), 57.6 (CH
)-4), 30.8 ((CH CHC
(CH )-4), 18.7 ((CH CHC
2
C
6
H
4
3
)
2
6
H
4
2
C
6
H
4
3
)
2
3
)
2
6
H
4
3
6
H
4
3 2
)
-
1
(CH
)
2
6
H
4
3
3
)
2
6
H
4
3
28 2 2
C H34Cl N Ru (570.56): C 58.94, H 6.01, N 4.92 Found: C 58.91, H 6.04, N 4.95.
o
1
1
7
4
d: (82%). mp 198-200 C, H NMR δ 8.14 (s, 1H, NCHN), [8.05 (d, J 8 Hz, 1H), 7.19 (t, J
.2 Hz, 1H), 6.97 (t, J 7.2 Hz, 1H), 6.73 (d, J 7.2 Hz, 1H) (NC CH N)], 6.69 (d, J 8.2 Hz,
H, C (N(CH )-4), 5.49, 5.27 (d, J 5.6 Hz, 4H, (CH CHC
CH N), 4.24 (s, 2H, CH )-4), 3.01 (hept, J
CHC (CH )-4), 2.96 (s, 6H, C )-4), 2.21 (s, 3H, (CH
), 1.32 (d, J 6.9 Hz, 6H, (CH CHC
28.1, 125.8, 125.5, 120.9 (NC
02.6, 97.4, 82.7, 81.7, (CH
6
H
4
2
6
H
4
3
)
2
3
)
2
6
H
4
(CH
3
)-4), 4.40 (s, 2H,
NC
6
H
4
2
2
C
6
H
4
(N(CH
3
)
2
6.9 Hz, 1H,
(
CH
3
)
2
6
H
4
3
6
H
4
(N(CH
3
)
1
2
3 2 6 4 3
) CHC H (CH )-
3
4
1
1
3
)
2
6
H
4
(CH
N), 150.9, 129.7, 129.2, 126.8 (C
CHC (CH )-4), 57.7 (CH (N(CH
)-4), 30.8 (CH CHC (CH
(CH )-4). υ(CN)=1621 cm . Anal. Calcd (%) for
Ru (571.55): C 56.74, H 5.82, N 7.35 Found: C 56.81, H 5.79, N 7.33.
3
)-4). C NMR δ 155.4 (NCHN), 140.8, 128.4,
(N(CH )-4),
)-4), 46.1
)-4), 22.6
6
H
4
CH
2
6
H
4
3 2
)
3
)
2
6
H
4
3
2
C
6
H
4
3 2
)
(
NC
CH
6
H
4
CH
2
N),
40.6
(C
6
H
4
(N(CH
3
)
2
3
)
2
6
H
4
3
-
1
(
3
)
2
CHC
6
H
4
(CH )-4), 18.7 (CH
3
3
)
2
CHC
6
H
4
3
C
27
H
33Cl
2
N
3
o
1
1
7
8
2
e: (89%). mp 204-206 C, H NMR δ 8.09 (s, 1H, NCHN), [8.04 (d, J 8.4 Hz, 1H), 7.16 (t, J
.2 Hz, 1H), 6.98 (t, J 7.6 Hz, 1H), 6.78 (d, J 7.2 Hz, 1H) (NC CH N)], 7.22 , 6.89 (d, J
.4 Hz, 4H, C (OCH )-4), 5.49, 5.27 (d, J 5.6 Hz, 4H, (CH CHC (CH )-4), 4.39 (s,
H, NC CH N), 4.19 (s, 2H, CH (OCH )-4), 3.79 (s, 3H, C (OCH )-4); 3.01 (hept,
CHC (CH )-4), 2.18 (s, 3H, (CH CHC (CH )-4), 1.31 (d, J 7.1
(CH )-4). C NMR δ 155.4 (NCHN), 140.6, 126.8, 125.9, 125.8,
CH N), 160.0, 130.1, 128.1, 114.6 (C (OCH )-4), 102.6, 97.4, 82.7,
(CH )-4), 57.3 (CH (OCH )-4), 46.2 (NC CH N), 55.6
)-4), 30.8 (CH CHC (CH )-4), 22.6 (CH CHC (CH )-4), 18.6
6
H
4
2
6
H
4
3
3
)
2
6
H
4
3
6
H
4
2
2
C
6
H
4
3
6
H
4
3
J 7.1 Hz, 1H, (CH
Hz, 6H, (CH CHC
25.6, 120.9, (NC
1.7 (CH CHC
(OCH
3
)
2
6
H
4
3
3
)
2
6
H
4
3
1
3
3
)
2
6
H
4
3
1
8
6
H
4
2
6
H
4
3
3
)
2
6
H
4
3
2
C
6
H
4
3
6
H
4
2
(C
6
H
4
3
3
)
2
6
H
4
3
3
)
2
6
H
4
3
8

-
1
(
CH
3
)
2
CHC
6 4 3 2 2
H (CH )-4). υ(CN)=1622cm . Anal. Calcd (%) for C26H30Cl N ORu (558.50): C
55.91, H 5.41, N 5.02 Found: C 55.87, H 5.44, N 5.06.
o
1
1
f: (61%). mp 227-229 C, H NMR δ 8.09 (s, 1H, NCHN), [8.07(d, J 8 Hz, 1H), 7.14 (t, J 8
CH N)], 6.12 (s, 2H,
(CH )-4), 4.49 (s, 2H,
-2,4,6), 3.88, 3.82 (s, 9H, C (OCH -2,4,6),
)-4), 2.11 (s, 3H, (CH CHC (CH )-4); 1.28
)-4). C NMR δ 156.4 (NCHN), 141.5, 127.9, 126.7,
N), 162.2, 160.1, 102.5, 90.5 (C (OCH -2,4,6), 102.6,
CHC (CH )-4), 56.1 (CH (OCH -2,4,6), 46.6
N), 55.7, 45.8 (C (OCH -2,4,6), 30.7 (CH CHC (CH )-4), 22.5
CHC (CH )-4), 18.4 (CH CHC (CH )-4). υ(CN)=1606 cm . Anal. Calcd (%) for
Ru (618.56): C 54.37, H 5.54, N 4.53 Found: C 54.33, H 5.52, N 4.57.
Hz, 1H), 6.96 (t, J 6.8 Hz, 1H), 6.76 (d, J 7.6 Hz, 1H) (NC
(OCH -2,4,6), 5.44, 5.20 (d, J 5.6 Hz, 4H, (CH CHC
CH N), 4.37 (s, 2H, CH (OCH
.98 (hept, J 6.9 Hz, 1H, (CH CHC (CH
d, J 6.9 Hz, 6H, (CH CHC (CH
25.5, 124.9, 121.5 (NC CH
6.9, 82.7, 81.9 ((CH
6
H
4
2
C
6
H
2
)
3 3
3
)
2
6
H
4
3
NC
6
H
4
2
2
C
6
H
2
3
)
3
6
H
2
3 3
)
2
3
)
2
6
H
4
3
3
)
2
6
H
4
3
1
3
(
)
3 2
6
H
4
3
1
9
6
H
4
2
6
H
2
3 3
)
3
)
2
6
H
4
3
2
6
C H
2
3 3
)
(NC
6
H
4
CH
2
6
H
2
)
3 3
3
)
2
6
H
4
3
-
1
((CH
)
3 2
6
H
4
3
3
)
2
6
H
4
3
28 2 2 3
C H34Cl N O
o
1
1
g: (77%). mp 213-215 C, H NMR δ 8.16 (s, 1H, NCHN), [7.99 (d, J 8 Hz, 1H), 7.19 (t, J
.2 Hz, 1H), 7.00 (t, J 7.6 Hz, 1H), 6.79 (d, J 7.2 Hz, 1H) (NC CH N)], 6.53 (s, 2H,
(OCH -3,4,5), 5.50, 5.29 (d, J 5.6 Hz, 4H, (CH CHC (CH )-4), 4.42 (s, 2H,
CH N), 4.24 (s, 2H, CH (OCH -3,4,5), 3.87, 3.83 (s, 9H, C (OCH -3,4,5),
.02 (hept, J 7.0 Hz, 1H, (CH CHC (CH )-4), 2.19 (s, 3H, (CH CHC (CH )-4), 1.31
d, J 7.0 Hz, 6H, (CH CHC (CH )-4). C NMR δ 155.6 (NCHN), 140.2, 128.1, 126.7,
CH N), 153.8, 138.4, 129.4, 106.4 (C (OCH -3,4,5), 102.6,
7.2, 82.7, 81.6 ((CH CHC (CH )-4), 56.8 (CH (OCH -2,4,6), 46.4
N), 61.0, 58.2 (C (OCH -3,4,5), 30.8 (CH CHC (CH )-4), 22.5
(CH )-4), 18.6 ((CH CHC (CH )-4).υ(CN)=1621 cm . Anal. Calcd (%) for
Ru (618.56): C 54.37, H 5.54, N 4.53 Found: C 54.34, H 5.52, N 4.55.
7
6
H
4
2
C
6
H
2
3
)
3
3
)
2
6
H
4
3
NC
6
H
4
2
2
C
6
H
2
3
)
3
6
H
2
3 3
)
3
3
)
2
6
H
4
3
3
)
2
6
H
4
3
1
3
(
3
)
2
6
H
4
3
126.0, 125.7, 120.9 (NC
6
H
4
2
6
H
2
3 3
)
9
3
)
2
6
H
4
3
2
C
6
H
2
3 3
)
(
NC
CH
6
H
4
CH
2
6
H
2
3
)
3
3
)
2
6
H
4
3
-
1
(
3
)
2
CHC
6
H
4
3
3
)
2
6
H
4
3
C
28
H
34Cl
2
N
2
O
3
o
1
2
: (70%). mp 223-225 C, H NMR δ 8.49 (s, 1H, NCHN), [8.12 (d, J 8.4 Hz, 1H), 7.07 (d, J
.8 Hz, 1H), 6.75 (s, 1H), (CH )C )], 7.21, 7.09 (d, J 7.6 Hz, 4H, (C (CH )), 5.49, 5.28
CHC (CH )-4), 4.91 (s, 2H, NC CH N), 3.02 (hept, J 6.9 Hz,
)-4), 2.35 (s, 3H, (C (CH )), 2.29 (s, 3H, C (CH )) 2.21 (s, 3H,
)-4), 1.29 (d, J 6.9 Hz, 6H, (CH )-4). C NMR δ 152.9
NCHN), 140.1, 136.3, 129.2, 126.9, 126.2, 121.1, (C )), 138.2, 136.1, 130.5, 119.2
)-4), 47.7 (NC CH N), 30.8
(CH ) and C (CH )),
8
3
6
H
3
6
H
4
3
(
d, J 5.6 Hz, 4H, (CH
3
)
2
6
H
4
3
6
H
3
2
1
H, (CH
3
)
2
CHC
6
H
4
(CH
3
6
H
3
3
6
H
4
3
1
3
(
(
(
(
CH
3
)
2
CHC
6
H
4
(CH
3
3
)
2
CHC
6
H
4
(CH
3
6
H
3
(CH
3
C
6
H
4
(CH
3
)), 102.6, 97.4, 82.8, 81.8 ((CH
(CH )-4), 22.6 ((CH CHC
3
)
2
CHC
6
H
4
(CH
3
6
H
3
2
(CH
)
3 2
CHC
6
H
4
3
3
)
2
6
H
4
(CH
3
)-4), 21.0 (C
6
H
4
3
6
H
3
3
9

-
1
1
8.7 ((CH
3 2 6 4 3 2 2
) CHC H (CH )-4). υ(CN)=1619 cm . Anal. Calcd (%) for C26H30Cl N Ru (542.51):
C 57.56, H 5.57, N 5.16 Found: C 57.51, H 5.55, N 5.19.
o
1
3
9
5
: (80%). mp 209-211 C, H NMR δ 8.35 (s, 1H, NCHN), [8.19 (d, J 8.8 Hz, 1H), 6.79 (d, J
.2 Hz, 1H), 6.45 (s, 1H) (OCH )C )], 7.14, 6.92, (d, J 8.4 Hz, 4H, C (OCH )), 5.49,
CHC (CH )-4), 4.91 (s, 2H, NC CH N), 3.80, (s, 3H,
(OCH )), 3.03 (hept, J 7.0 Hz, 1H, (CH CHC (CH )-4),
)-4), 1.29 (d, J 7.0 Hz, 6H, (CH CHC (CH
NMR δ 152.2 (NCHN), 157.9, 134.1, 128.4, 122.4, 113.4, 110.9, (C (OCH )), 158.1,
35.9, 121.2, 115.2 (C (OCH )), 102.6, 97.3, 82.8, 81.7 (CH CHC (CH )-4), 48.3
(OCH )), 55.7 (C (OCH )), 30.8 ((CH CHC (CH )-4), 22.6
)-4), 18.7 ((CH CHC (CH )-4). υ(CN)=1615cm . Anal. Calcd (%) for
Ru (574.50): C 54.36, H 5.26, N 4.88 Found: C 54.38, H 5.24, N 4.85.
3
6
H
3
6
H
4
3
.27 (d, J 5.6 Hz, 4H, (CH
(OCH )), 3.78 (s, 3H, C
.21 (s, 3H, (CH CHC
3
)
2
6
H
4
3
6
H
3
2
C
6
H
3
3
6
H
4
3
3
)
2
6
H
4
3
1
3
2
3
)
2
6
H
4
(CH
3
3
)
2
6
H
4
3
)-4). C
6
H
3
3
1
6
H
4
3
3
)
2
6
H
4
3
(NC
6
H
3
CH
2
N), 55.8 (C
6
H
4
3
6
H
3
3
3
)
2
6
H
4
3
-
1
((CH
3
)
2
CHC
6
H
4
(CH
3
3
)
2
6
H
4
3
26 2 2 2
C H30Cl N O
o
1
1
-Methylimidazole Ru(II): (83%). mp 182-184 C, H NMR δ 7.87 (s, 1H, NCHN), 7.29,
.88 (s, 2H,NHC=CHN), 5.45, 5.27 (d, J 5.6 Hz, 4H, (CH CHC (CH )-4), 3.64 (s, 3H,
), 2.97 (hept, J 7.0 Hz, 1H, (CH CHC (CH )-4), 2.18 (s, 3H, (CH CHC (CH )-
), 1.28 (d, J 7.0 Hz, 6H, (CH CHC (CH )-4). C NMR δ 140.5 (NCHN), 132.2, 121.1,
NHC=CHN), 102.7, 97.4, 82.7, 81.6 ((CH CHC (CH )-4), 34.8 (NCH ), 30.9
(CH )-4), 18.7 ((CH CHC (CH )-4).
Ru (388.29): C 43.30, H 5.19, N 7.21
6
3
)
2
6
H
4
3
NCH
3
3
)
2
6
H
4
3
3
)
2
6
H
4
3
1
3
4
3
)
2
6
H
4
3
(
(
3
)
2
6
H
4
3
3
(CH
3
)
2
CHC
6
H
4
(CH
3
)-4), 22.4 ((CH
3
)
2
CHC
6
H
4
3
3
)
2
6
H
4
3
-
1
υ
(CN)=1536 cm . Anal. Calcd (%) for C14
H
20Cl
2
N
2
Found: C 43.37, H 5.16, N 7.23.
o
1
1
2
2
,2-Dimethylimidazole Ru(II): (80%). mp 218-220 C, H NMR δ 7.29, 6.74 (d, J 1.6 Hz,
H, NHC=CHN), 5.41, 5.22 (d, J 5.6 Hz, 4H, (CH CHC (CH )-4), 3.54 (s, 3H, NCH ),
.92 (hept, J 7.0 Hz, 1H, (CH CHC (CH )-4), 2.67 (s, 3H, NC(CH )N), 2.09 (s, 3H,
CHC (CH )-4), 1.28 (d, J 7.0 Hz, 6H, (CH
NC(CH )N), 129.9, 120.5 (NHC=CHN), 102.7, 97.3, 82.7, 81.5 ((CH
4.8 (NCH ), 30.7 ((CH CHC (CH )-4), 22.5 ((CH CHC
(CH CHC (CH )-4), 14.3 (NC(CH )N). υ(CN)=1508 cm . Anal. Calcd (%) for
Ru (402.32): C 44.78, H 5.51, N 6.96 Found: C 44.73, H 5.53, N 6.93.
3
)
2
6
H
4
3
3
3
)
2
6
H
4
3
3
1
3
(
(
CH
3
)
2
6
H
4
3
3
)
2
CHC
6
H
4
(CH
3
)-4). C NMR δ 147.9
CHC (CH )-4),
(CH )-4), 18.5
3
3
)
2
6
H
4
3
3
3
3
)
2
6
H
4
3
3
)
2
6
H
4
3
-
1
(
3
)
2
6
H
4
3
3
C
15 2 2
H22Cl N
2.7 General procedure for the transfer hydrogenation reaction
The Ru(II) complexes (1 mol %) and acetophenone (1 mmol) were placed in a two
necked flask and 10 mL 2-propanol was added to the mixture which was stirred for 10 min at
1
0

o
room temperature. Then 0.4 mol % KOH was added to the mixture and it was heated at 82 C
for the desired period of time. After that, volatiles were removed under reduced pressure and
1
conversions were determined by H NMR spectroscopy.
3. Results and discussion
3.1 Synthesis of N-benzyl or -aryl substituted 3,4-dihydroquinazolines, (D, E and F) and their
ruthenium(II) complexes (1-3)
The synthesis of N-benzyl substituted 3,4-dihydroquinazolines were performed in a
three-step reaction, starting from commercially available 2-aminobenzylamine (Scheme 1).
The reaction of 2-aminobenzylamine with different benzaldehyde derivatives to obtain imine
compounds resulted with the formation of ring-chain tautomerizm, so the mixture of 2-aryl-
1,2,3,4-tetrahydroquinazolines (B) and 2-aminobenzyl substituted imines (A) were obtained
with different ratios depending on the substituents of the benzaldehydes. The tautomeric
mixture (without any separation) was reduced to mono substituted benzylamine derivatives
(C), then the ring was closed with Me
2 2
NCH(OMe) to obtain the target compound D.
N-aryl substituted 3,4-dihydroquinazolines (E and F) were obtained by the reaction of
[39-47]
p-substituted aniline derivatives with formalin and formic acid in a one-step reaction.
3,4-Dihydroquinazolines (D, E and F) were characterized by spectroscopic methods and the
data for the intermediates (A, B) are given in the supplementary material.
1
13
The H and C NMR of D, E and F showed that the NCHN resonances occurred
1
between 6.97-7.47 ppm and 145.9-151.2 ppm, respectively. The H NMR values showed that
2
the C -H signals shifted to low field in the N-aryl 3,4-dihydroquinazolines as compared to N-
benzyl analogues due to an electron withdrawing effect of the aryl substituent.
The ESI mass spectra of compounds (1a and 2) contained peaks at m/z values assignable
to the N-ligands which indicates decomposition of the complexes under the conditions
(supplementary material).
Scheme 1. Synthesis of N-alkyl and N-aryl substituted quinazolines (D, E and F) and their
complexation with [(p-cymene)RuCl dimer.
2 2
]
N-substituted-3,4-dihydroquinazolines were used as nucleophiles to cleave [(p-
cymene)RuCl dimer and the resultant piano-stool ruthenium(II) complexes (1-3) were
2 2
]
1
1

obtained in high yield. All complexes have been isolated as orange solids and are stable in the
solid state and in solution. The structures of the complexes were confirmed by IR and NMR
1
13
spectroscopy. The H and C NMR spectra of complex 1a were given as a sample in
supplementary material. The structure of 1a was also confirmed by X-ray crystallography.
The presence of the –C=N– group in the complexes was verified by the υ(C=N) vibrations
-
1
1
13
between 1606-1622 cm . H and C NMR chemical shifts and the integrations of the signals
were consistent with the proposed structures. The protons of p-cymene displayed two doublets
2 2
at ca 5.15-5.50 ppm. The chemical shift of C -H is sensitive to formation of complexes. C -H
shifts to low field ca. 1 ppm when complexes are formed (7.74-8.49 ppm). In addition, the
signals of the N-substituents have been assigned to the corresponding protons. The imino
1
3
2
carbons C appeared as typical singlets between 152.2-156.4 ppm in C NMR spectra.
3.2 Crystal structures:
The molecular structure of complex 1a including atom-numbering is shown in Fig. 1.
Crystal data and additional data collection parameters and refinement details are presented in
Table 1. Selected bond distances and angles are given in Table 2. The complex (1a)
crystallizes in the triclinic space groups P-1 (no:2). The complex adopt a distorted piano-stool
6
type structure with the ruthenium atom being η -coordinated p-cymene ligand with an
average Ru–C distances of 2.145(5)-2.208(5) Å, while the distances between the ruthenium
atom and the centroid of the p-cymene ring is 1.656(5)Å which is similar to those observed
[
51-52]
for p-cymene ruthenium complexes.
The ruthenium atom is also directly coordinated to
nitrogen atoms of the 3-(2,4,6-trimethylbenzyl)-3,4-dihydroquinazoline ligand, with a normal
distance (Ru-N1=2.165(3) Å) and average Ru-C distance is 2.175(3) Å. The Ru–Cl bond
lengths are also normal and comparable with the other ruthenium(II) half-sandwich
[51]
complexes. The angles between the nitrogen heteroaromatic ligands and chlorine ligands in
the complex are close to those observed in the ruthenium(II) arene compounds. In the crystal
structure of complex (1a) no classical hydrogen bonds are present.
Figure 1. The molecular structure of (1a). Displacement ellipsoids are drawn at the 40%
probability level.
1
2

Table 2
3.3 Transfer hydrogenation reaction
Catalytic transfer hydrogenation is an important way to achieve reduction reactions
which is one of the most fundamental and useful reactions in organic synthesis, to drive a
large number of chemical processes. Whilst direct hydrogenation of unsaturated molecules is
more widely applied, transfer hydrogenation is an attractive alternative because the use of a
potentially dangerous high pressure of H
propanol) or an HCOOH/NEt mixture is used as a hydrogen-donor source under the catalytic
influence of metal complexes. The protocols are simple, mild and the reaction can be highly
2
is avoided. In general, secondary alcohols (often 2-
3
[53-54]
chemo- and enantioselective.
Transfer hydrogenation has been described for the
reduction of carbonyl, imine, nitro and olefin functionalities in the presence of Ru(II), Rh(I)
[
53]
and Ir(I) complexes. The capability of ruthenium(II) complexes to dehydrogenate alcohols
and deliver the hydride and a proton to a ketone has made them useful as transfer
hydrogenation catalysts. Also the ligand moiety is as important as metal species in the
[
54-55]
progression of a catalytic reaction. The established mechanism
involving complexes
operates via a mono- or dihydride intermediate and may incorporate a coordinated -NH
functionality. However non -NH containing catalysts which display excellent activity are also
[
56]
known.
The transfer hydrogenation reactions of acetophenone were carried out in the presence
of catalyst (1 mol %) (1-3) and KOH (0.4 mol %) in 2-propanol (10 mL) and the mixtures
were analyzed in periods of 5-60 min (Fig. 2).
PhMeC=O + Me
2
CHOH
2
PhCH(OH)Me + Me C=O
Figure 2. Time-dependent in conversions of acetophenone: yields are recorded as the average
o
of three runs. Reaction conditions: (1 mol %) 1-3, 0.4 mol % KOH, 82 C.
All the complexes showed good to excellent performance after 1h in the conversion of
acetophenone to alcohol. The reaction rate was sensitive to changes on the N-substituent: 1a
and 1f were found to be the most active catalysts whereas complexes 2 and 3 showed
significantly lower activity in comparison to 1. Clearly, It appears that electron donating
substituents on the N atom increased the yield. In addition, each complex has different
1
3

[
57]
initiation period, thus they didn’t show similar catalytic behavior in 1h reaction time.
The
most efficient complex 1a was used to investigate effect of catalyst loading. Decreasing the
load of catalyst to 0.5 mol % and 0.1 mol % resulted in 74% and 50% conversions,
respectively. Thus, the rest of catalytic reactions were carried out with 1 mol % catalyst
loading. It was observed that the efficiency of the complexes was reduced if KOH is not
used. For example, 1a exhibits only 44% conversion in the absence of KOH. The decrease of
the activity in the absence of base suggests that the reaction may not proceed by the outher-
[
58]
sphere bifunctional mechanism proposed by Noyori et al.
formation of [Ru]-H species as active species via β-elemination of [Ru]-OCHMe
Subsequently the ketone coordinates to [Ru]-H intermediates and then reduced to seconder
The base facilitates the
2
.
[
52, 59]
alcohol by the inner-sphere mechanism.
However, we have not observed any sign of
1
[
Ru]-H signal in the H NMR experiment (see Supplementary Material, Fig.E).
2 2
When [(p-cymene)RuCl ] dimer was used in transfer hydrogenation reaction of
acetophenone, 15% conversion was obtained at the end of 60 min period. In order to compare
1
the efficiency of benzimidazole and 3,4-dihydroquinazoline ligand, the corresponding N -
2,4,6-trimethylbenzyl substituted benzimidazole Ru(II) complex was synthesized [16] and
used in transfer hydrogenation reaction of acetophenone under the same condition. The
conversion was lower (46%) than the corresponding 3,4-dihydroquinazoline bearing
ruthenium complex 1a (Fig. 3).
PhMeC=O + Me
2
CHOH
2
PhCH(OH)Me + Me C=O
Figure 3. The comparison of 1a with benzimidazole, 1-methylimidazole, 1,2-
dimethylimidazole complexes and [(p-cymene)RuCl in the time-dependent conversions of
2 2
]
acetophenone: yields are recorded as the average of three runs. Reaction conditions: 1 mol %
o
cat., 0.4 mol % KOH, 82 C.
Additionally, the catalyst 1a was used in transfer hydrogenation of different ketones to
investigate the effect of substituents on ketones. It was observed that electron-withdrawing
groups in the para position of the acetophenone increased the yield whereas electron donating
groups at the para position of the acetophenone decreased (Fig. 4).
1
4

R
1
R
2
C=O + Me
2
CHOH
1 2 2
R CH(OH)R + Me C=O
Figure 4. Time-dependent in conversions of different ketones catalyzed with 1a: yields are
recorded as the average of three runs. Reaction conditions: 1 mol % 1a, 0.4 mol % KOH,
o
8
2 C.
Additional experiments were carried out with 1a to understand mechanism of transfer
hydrogenation reaction with 3,4-dihydroquinazoline Ru(II) complexes. The complex 1a
showed NCHN resonance at 7.93 ppm in d -methanol. But when base (KOH) was added to
this solution NCHN resonance of complex immediately shifts to high field ca. 1 ppm (6.97
ppm). This observation suggests that the C -H functionality on the dihydroquinazoline plays
an important role. Besides, the chemical shift (acidity) of C -H of 1-3 is related with the
1
2
2
catalytic conversion. Thus, complex 1a was found to be the least acidic and the most
effective catalyst. To support this hypothesis, 1-methyl and 1,2-dimethylimidazole Ru(II)
complexes were synthesized and tested. 1,2-Dimethylimidazole Ru(II) complex which do not
contain C
. Conclusion
In this study we reported a straightforward synthesis of N-coordinated- imidazole,
2
-H, showed much lower activity than 1-methylimidazole complex (Fig. 3).
4
benzimidazole and 3,4-dihydroquinazoline ruthenium(II) complexes. The resulting piano-
stool ruthenium complexes bearing 3,4-dihydroquinazoline ligand (1-3) showed good to
o
excellent activity as transfer hydrogenation catalysts for reduction of acetophenone at 82 C.
Among the complexes studied, 2,4,6-trimethylbenzyl and 2,4,6-trimethoxybenzyl substituted
complexes, 1a and 1f were found to be the most active catalysts. It is worth mentioning that
C
2
-H functionality in the quinazoline complexes appears to play an important role in the
catalytic steps.
1
5

Supplementary Material
Ru(II)-Arene Complexes with N-Substituted 3,4-Dihydroquinazoline Ligands and Catalytic
Activity for Transfer Hydrogenation Reaction
Deniz Mercan, Engin Çetinkaya*, Ertan Şahin
1
H NMR data for the intermediates (A, B):
1
Aa+Ba (78%). (Ba/Aa)(%): 45/55. Aa: H NMR δ 8.69 (s, 1H, HC=N), [7.07 (d, J 7.6 Hz,
2
2
5
H), 7.01 (t, J 7.6 Hz, 1H), 6.94 (d, J 7.2, 1H) (NH
,4,6), 4.74 (s, 2H, NH CH N), 2.38, 2.26 (s, 9H, C
.61 (s, 1H, HN-CH-NH), 6.84 (s, 2H, C (CH
CH NH), [4.29 (d, J 16.8 Hz, 1H) and 4.02 (d, J 16.4 Hz, 1H) (NHC
.46, 2.25, (s, 9H, C (CH -2,4,6).
2
C
6
H
4
CH
2
N)], 6.84 (s, 2H, C
6
H
2
(CH
-2,4,6). Ba: H NMR δ
-2,4,6), 6.65-6.72 (m, 4H,
CH NH)],
3 3
) -
1
2
C
6
H
4
2
6 2 3 3
H (CH )
6
H
2
3 3
)
NHC
6
H
4
2
6
H
4
2
2
6
H
2
3 3
)
1
Ab+Bb (70%) (Bb/Ab)(%): 45/55 Ab: H NMR δ 8.28 (s, 1H, HC=N), [7.59(d, J 7.6 Hz, 2H),
Other signals overlap with the ring hydrogens (NH
NH CH
HN-CH-NH), [7.36 (d, J 7.2 Hz, 2H) and 7.17 (d, J 7.2 Hz, 2H, C
Hz, 1H), 6.90 (d, J 7.6 Hz, 1H), 6.69 (t, J 7.2 Hz, 1H), 6.53 (d, J 8 Hz, 1H),
NHC CH NH)], [4.21(d, J 16.4 Hz, 1H) and 3.93 (d, J 16.4 Hz, 1H) (NHC CH NH)],
.34 (s, 3H,C (CH )-4).
2
C
6
H
4
CH
2
N)], 4.71 (s, 2H,
1
2
C
6
H
4
2
N), Other signals overlap with the ring hydrogens Bb: H NMR δ 5.15 (s, 1H,
6
4 3
H (CH )-4)], [7.01 (t, J 7.6
(
6
H
4
2
6
H
4
2
2
6
H
4
3
1
Ac+Bc (70%). (Bc/Ac)(%): 83/17 Ac: H NMR δ 8.29 (s, 1H, HC=N) ,[7.63(d, J 8 Hz, 2H),
Other signals overlap with the ring hydrogens (NH
2
C
6
H
4
CH
2
N)],
4.71 (s, 2H,
1
NH
2
C
6
H
4
CH
2
N), Bc: H NMR δ 5.16 (s, 1H, HN-CH-NH), [7.40 (d, J 8 Hz, 2H) and 7.23 (d,
J 8.4 Hz, 2H) C
6
H
4
(CH(CH
H), 6.52 (d, J 8 Hz, 1H), (NHC
H) (NHC CH NH)], 2.90 (hept, J 8 Hz, 1H, C
(CH(CH )-4).
3
)
2
)-4)], [7.05 (t, J 6.8 Hz, 1H), 6.90 (d, J 7.6 Hz, 1H), 6.68 (m,
CH NH)], [4.22 (d, J 16.4 Hz, 1H) and 3.94 (d, J 16.8 Hz,
(CH(CH )-4), 1.26 (d, J 8 Hz, 6H,
1
1
6
H
4
2
6
H
4
2
6
H
4
3 2
)
C
6
H
4
3 2
)
1
Ad+Bd (70%) (Bd/Ad)(%): 45/55 Ad: H NMR δ 8.25 (s, 1H, HC=N), [7.63(d, J 9.2 Hz, 2H),
7
.17-7.09 (m, 2H) (NH
NH CH N), 3.02 (s, 6H, CH
NH), [7.39 (d, J 8.8, 2H), 6.76 (d, J 8., 2H ) (CH
2
C
6
H
4
CH
2
2 6 4 3 2
N)], 6.74-6.69 (m, 4H CH C H (N(CH ) )-4), 4.72 (s, 2H,
1
2
C
6
H
4
2
2
6
C H
4
(N(CH
3
)
2
)-4). Bd: H NMR δ 5.16 (s, 1H, HN-CH-
2
C
6
H
4
(N(CH
3
)
2
)-4)], [7.06(t, J 7.2Hz, 1H),
CH NH)], [4.28 (d, J
6.95(d, J 7.2 Hz, 1H), 6.74-6.69 (m, 1H), 6.56(d, J 7.6 Hz, 1H) (NHC
6
H
4
2
1
6

1
6.8 Hz, 1H) and 3.99 (d, J 16.8 Hz, 1H), (NHC
6 4 2
H CH NH)], 2.97 (s, 6H,
CH (N(CH )-4).
2
C
6
H
4
3 2
)
1
Ae+Be (70%) (Be/Ae)(%): 45/55 Ae: H NMR δ 8.25 (s, 1H, HC=N), [7.64 (d, J 8 Hz, 2H);
Other signals overlap with the ring hydrogens,(NH CH N)], 4.69 (s, 2H,
)-4), Other signals overlap with the ring
2
6
C H
4
2
NH
2
C
6
H
4
CH
2
2 6 4 3
N), 3.79 (s, 3H, CH C H (OCH
1
hydrogens Be: H NMR δ 5.13 (s, 1H, HN-CH-NH), [7.67 (t, J 8 Hz, 1H), 6.90 (d, J 6.4 Hz,
1
6
1
H), 6.69 (t, J 7.6Hz, 1H), 6.52 (d, J 8 Hz, 1H) (NHC
.88 (d, J 8 Hz, 2H, (CH (OCH )-4)], [4.21(d, J 16.8 Hz, 1H) and 3.93 (d, J 16.8 Hz,
H) (NHC CH NH)], 3.78(s, 3H, CH (OCH )-4).
6 4 2
H CH NH)], [7.39 (d, J 8.4 Hz, 4H),
2
C
6
H
4
3
6
H
4
2
2
C
6
H
4
3
1
Af+Bf (96%). (Bf/Af)(%): 83/17. Af: H NMR δ 8.65 (s, 1H, HC=N), 4.72 (s, 2H,
1
NH
2
C
6
H
4
CH
2
N), Other signals overlap with the ring hydrogens. Bf: H NMR δ 5.65 (s, 1H,
HN-HC-NH), [7.02 (t, J 7.6 Hz, 1H), 6.95 (d, J 7.6 Hz, 1H), 6.72 (t, J 7.6Hz, 1H), 6.58 (d, J
.6 Hz, 1H), (NHC CH NH)], 6.14 (s, 2H, C (OCH -2,4,6), [4.26 (d, J 16.4 Hz, 1H)
and 4.02 (d, J 16.8 Hz, 1H) (NHC
7
6
H
4
2
6
H
2
3 3
)
6
H
4
CH
2
6 2 3 3
NH)], 3.82, 3.81 (s, 9H, C H (OCH ) -2,4,6).
1
Ag+Bg (56%). (Bg/Ag)(%): 89/11. Ag: H NMR δ 8.23 (s, 1H, HC=N), 4.72 (s, 2H,
1
NH
2
C
6
H
4
CH
2
N), Other signals overlap with the ring hydrogens. Bg: H NMR δ 5.13 (s, 1H,
HN-HC-NH), [7.04 (t, J 8 Hz, 1H), 6.94 (d, J 7.2 Hz, 1H), 6.72 (t, J 7.6 Hz, 1H), 6.59 (d, J
8
1
3
.4 Hz, 1H) (NHC
6
H
4
CH
2
NH)], 6.75 (s, 2H, CH
2
C
6
H
2
(OCH
3
)
3
-3,4,5), [4.25 (d, J 16.8 Hz,
H), and 3.98 (d, J 16.4 Hz, 1H) (NH
2
C
6
H
4
CH
2
NH)], 3.85, 3.83 (s, 9H, CH
2
6
C H
2
(OCH
3 3
) -
,4,5).
1
13
H NMR and C NMR data for the intermediates (Cb, Ce):
1
Cb: (78%). Liquid, H NMR δ 7.18, 7.12 (d, J 8 Hz, 4H, CH
2
C
6
H
4
(CH
NH)], 4.70 (s, 2H, NH
)-4), 2.32 (s, 3H, CH (CH )-4). C
NMR δ 147.2, 130.2, 128.6, 124.2, 117.9, 115.9 (NH CH NH), 137.5, 136.8, 129.4,
CH NH), 21.4 (C (CH )-4).
3
)-4), [7.06-7.04 (m,
1
H), 7. 00 (d, J 6.8 Hz, 1H),6.71-6.66 (m, 2H) (NH
2
6
C H
4
CH
2
2
), 3.79
1
3
(
s, 2H, NH CH NH) 3.72 (s, 2H, CH (CH
C
2 6
H
4
2
2
6
C H
4
3
2
C
6
H
4
3
2
C
6
H
4
2
1
28.4 (C
6
H
4
(CH
3
)-4), 53.3 (CH
2
6
C H
4
(CH
3
)-4), 52.6 (NH
C
2 6
H
4
2
6
H
4
3
1
Ce: (92%). Liquid, H NMR δ 7.19, 6.83 (d, J 8.4 Hz, 4H, CH
2
C
6
H
4
(OCH
NH)], 4.65 (s, 2H, NH
(OCH )-4), 3.79 (s, 3H,
)-4) C NMR δ 147.2, 130.2, 128.6, 124.2, 117.9, 115.9 (NH CH NH),
3
)-4), [7.06-7.04
(
m; 1H), 6.98 ( d, J 7.2 Hz, 1H), 6.69-6.62 (m, 2H), (NH
2
C
6
H
4
CH
2
2
),
3
.77 (s, 2H, NH
2
C
6
H
4
CH
2
NH) 3.71 (s, 2H, CH
2
C
6
H
4
3
1
3
CH
2
C
6
H
4
(OCH
3
2
C
6
H
4
2
1
7

1
5
58.9, 132.7, 129.6, 114.1 (C
6 4 3 6 4 3 2 6 4 3
H (CH )-4), 55.5 (C H (OCH )-4), 52.9 (CH C H (OCH )-4),
2.5 (NH CH NH).
2
C
6
H
4
2
1
13
H NMR and C NMR data for the compounds (E,F):
o
1
E: (40%). mp 157-159 C, H NMR δ 7.47 (s, 1H, NCHN), [7.08 (d, J 8 Hz, 1 H), 7.02 (d, J
Hz, 1H), 6.76 (s, 1H) (CH )C )], 7.19, 7.02 (d, J 8 Hz, 4H, (C (CH )), 4.83 (s, 2H,
NC CH N), 2.34 (s, 3H, (C )). C NMR δ 146.5
NCHN), 141.2, 135.5, 129.3, 126.5, 124.8, 121.2, (C )), 139.0, 134.4, 130.3, 118.3
(CH )), 47.4 (NC CH N), 21.3, 20.9 (C (CH
(236.31): C 81.32, H 6.82, N 11.85 Found: C 81.35, H 6.81, N
8
3
6
H
3
6
H
4
3
1
3
6
H
3
2
6
H
3
(CH
3
)), 2.29 (s, 3H, C
6
4 3
H (CH
(
(
6 3
H
(CH
3
-
1
C
6
H
4
3
6
H
3
2
6
H
4
3 6 3 3
) and C H (CH )). υ(CN)=1619 cm .
16 2
Anal. Calcd (%) for C16H N
1
1.83.
o
1
F: (46%). mp 134-136 C, H NMR δ 7.33 (s, 1H, NCHN), [7.09 (d, J 8.8 Hz, 1H), 6.74 (dd,
J 8.8, 2.8 Hz, 1 H), 6.47 (d, J 2.8 Hz, 1 H) (CH )C )], 7.05, 6.91 (d, J 8 Hz, 4H, (C
N), 3.78 (s, 3H, (C (OCH )), 3.75 (s, 3H, C (OCH
(OCH )), 157.1,
N), 55.8, 55.7 (C (OCH ) and
(268.31): C 71.62, H 6.01, N
3
6
H
3
6 4
H
(
OCH
3
)), 4.82 (s, 2H, NC
6
H
3
CH
2
6
H
3
3
6
H
4
3
)).
1
3
C NMR δ 145.9 (NCHN), 157.8, 137.2, 122.3, 120.3, 115.0, 111.4 (C
(OCH )), 47.9 (NC CH
)). υ(CN)=1620 cm . Anal. Calcd (%) for C16
0.44 Found: C 71.65, H 6.04, N 10.40.
6
H
3
3
1
35.0, 125.9, 113.6 (C
6
H
4
3
6
H
3
2
6
H
4
3
-
1
C
6
H
3
(OCH
3
14 2 2
H N O
1
1
8

1
Figure A: H NMR spectrum of complex 1a
1
3
Figure B: C NMR spectrum of complex 1a
1
9

1
Figure C: H NMR spectrum of complex 1a in CD
3
OD
1
Figure D: H NMR spectrum of complex 1a+KOH in CD
3
OD
1
Figure E: H NMR spectrum of complex 1a+KOH+2-propanol in CD
3
OD
2
0

1
0
9
8
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
Table A: The NCHN resonances of ligands (D,E-F) and complexes 1-3.
Ligand
Da
Db
Dc
Dd
De
Df
NCHN
6.97
7.23
7.19
7.22
7.19
7.18
7.17
7.47
7.33
Complex
NCHN
7.74
8.16
8.11
8.14
8.09
8.09
8.16
8.49
8.35
1a
1b
1c
1d
1e
1f
1g
2
Dg
E
F
3
Table B: Influence of catalyst and low catalyst loading transfer hydrogenation of
acetophenon
2
1

Entry
Catalyst
1a
1b
1c
Mol %
Yield
97
TON
97
TOF
97
1
2
3
4
5
6
7
8
9
1
1
73
73
73
1
78
78
78
1d
1e
1
86
86
86
1
72
72
72
1f
1
94
94
94
1g
2
1
66
66
66
1
69
69
69
3
1
65
65
65
1
1
0
1
1a
1a
0.5
0.1
74
148
500
148
50
500
o
Reaction conditions: 1 mmol acetophenone, 0.4 mol % KOH,1h, 82 C.
Spectral Data:
1
H spectrum of Aa+Ba
2
2

1
H spectrum of Ab+Bb
1
H spectrum of Ac+Bc
2
3

1
H spectrum of Ad+Bd
1
H spectrum of Ae+Be
2
4

1
H spectrum of Af+Bf
1
H spectrum of Ag+Bg
2
5

OCH3
OCH3
OCH2
OCH3
OCH3
OCH3
N
NH
NH
NH2
Ag+Bg
1
13
H and C spectrum of Ca
2
6

2
150
130
110
90 80 70 60 50 40 30 20 10
f1 (ppm)
0
1
13
H and C spectrum of Cb
2
7

2
1
13
H and C spectrum of Cc
2
8

1
13
H and C spectrum of Cd
2
9