Preparation of Different Substitued Polypyridine Ligands, Ruthenium(II)-Bridged Complexes and Spectoscop?c Studies

Article abstract of DOI:10.1007/s10895-016-1859-3

Novel different substitued polypyridine ligands 4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzaldehyde (BA-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzylidene)-pyrene-4-amine (PR-PPY), (E)-N-(4-

Full text of DOI:10.1007/s10895-016-1859-3

J Fluoresc
DOI 10.1007/s10895-016-1859-3
ORIGINAL ARTICLE
Preparation of Different Substitued Polypyridine Ligands,
Ruthenium(II)-Bridged Complexes and Spectoscopıc Studies
Aslihan Yilmaz Obali1 & Halil Ismet Ucan1
Received: 26 February 2016 /Accepted: 14 June 2016
#
Springer Science+Business Media New York 2016
Abstract Novel different substitued polypyridine ligands
4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzaldehyde (BA-PPY), (E)-
N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-pyrene-4-amine (PR-PPY),
(E)-N-(4-((4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-1,10-phenanthroline-
5amine (FN-PPY), 2-(4-(bromomethyl)phenyl)-1H-
imidazo[4,5-f][1,10] phenanthroline (BR-PPY),
2-(4-(azidomethyl)phenyl)-1H-imidazo[4,5-f][1,
10]phenanthroline (N3-PPY) and triazole containing
polypyridine ligand 3,4-bis[(4-(metoxy)-1,2,3-triazole)1-
methylphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)]
benzaldehyde (BA-DIPPY) and Ruthenium(II) complexes
were synthesized and characterized. Their photopysical prop-
erties were investigated. The complexes RuP(PR-PPY),
RuB(PR-PPY, RuP(FN-PPY) and RuB(FN-PPY) exhibited a
broad absorption bands at 485, 475, 476, and 453 nm, respec-
tively, assignable to the spin-allowed MLCT (dπ–π*) transi-
tion. The emission maxima of the pyrene-appended
polypyridine ligand PR-PPY was observed at
λems = 616 nm and the phenanthroline-appended
polypyridine ligand FN-PPY was observed at
λems = 668 nm. And the emission maxima of the complexes
RuP(PR-PPY), RuB(PR-PPY), RuP(FN-PPY) and RuB(FN-
PPY) were observed at λems = 646, 646, 685 and 685 nm,
respectively. As seen in fluorescence spectra, the fluorescence
intensities of the ligands are higher than their metal
complexes. This is because of quenching effect of
Ruthenium(II) metal on chromophore groups.
.
.
.
Keywords Polypyridine Ruthenium(II)complex Triazole
Different substitued ligands
Introduction
There is nowadays much interest in the design of photoin-
duced energy and electron transfer systems due to their poten-
tial applications in fields as artificial photosynthesis,
photocatalysis, molecular informatics and so on [1–5].
Imidazo[4,5-f]-1,10-phenanthroline containing polypyridyl li-
gands and complexes have been extensively studied as a result
of their remarkable photophysical properties and chemical
stability. Tremendous interest has been attracted to mononu-
clear and dinuclear Ruthenium(II) polypyridine complexes
with regard to the photochemical molecular devices, solar
energy related research, molecular wires, DNA probes, sen-
sors and switches [6–10]. Schiff base containing polypyridine
ligands and complexes have also significant interest because
of their excellent chemical, electrochemical and photochemi-
cal behavious as well as potential biological applications such
as antitumor, antibacterial and antimicrobial activities [6,
11–13]. Fluorescent groups as phenanthroline or pyrene con-
tribute additional photopysical properties to the Schiff base
polypyridyl ligands. Among the existent fluorescent groups,
phenanthroline and pyrene reveals to be one of the most com-
monly used fluorophores due to its peculiar fluorescence prop-
erties: intense fluorescence signals, long lifetime values [14,
15]. Because of these remarkable properties we have designed
two of our novel ligands as fluorescent Schiff base molecules.
In this paper we have synthesized a series of molecules
starting from organic ligands containing imidazo[4,5-f]-1,10-
* Aslihan Yilmaz Obali
aslihanyilmaz84@gmail.com
1
Department of Chemistry, Science Faculty, Selcuk University,
Campus, 42075 Konya, Turkey

J Fluoresc
phenanthroline group. They are different substitued
polypyridine ligands and they could be classifed as fluorescent
Schiff base ligands, triazole containing ligand, aldeyde-ended
ligand, bromine-ended ligand and azide-ended ligand. Triazole
containing polypyridine ligand BA-DIPPY has been synthe-
sized by copper-catalyzed azide–alkyne cycloaddition
(CuAAC) reaction. Due to its high efficiency, functional group
tolerance, simple purification procedure and compatibility with
various solvents, the (CuAAC) has received remarkable atten-
tion. In addition to its role as a connector, the resulting 1,2,3-
triazole has also recently been highlighted as a ligand for metal
ions, in sensing, luminescence and magnetism [16, 17].
with dichloromethane and evaporated to dryness. The crude
product was recrystallized from methanol to provide the de-
sired product in 85–90 % [18].
FT-IR: 1683 (C = O), 1573, 1557, 1455, 1412, 1290, 1202,
1112, 922, 813, 736. 1H NMR (CDCl3): δ = 7.62 (d, 2H), 8.53
(dd, 2H), 7.40 (dd,2H), 9.15 (dd,2H).
4-(1H-Imidazo[4,5-f][1,10]Phenanthroline-2-yl)Phenol
1,10-Phenanthroline-5,6-dione (0.1 g, 0.46 mmol) and ammo-
nium acetate (0.58 g, 13.3 mmol) were dissolved in 10 mL of
hot glacial acetic acid. While the mixture was stirred, a solu-
tion of 4-hydroxybenzaldehyde (0.056 g, 0.46 mmol) in
10 mL of glacial acetic acid was added dropwise to the mix-
ture. The mixture was heated at 90 °C for 3 h and was then
poured in 200 mL of water. The solution was neutralized with
ammonia to pH:7 and was then cooled to room temperature.
The precipitate was filtered off and washed with large portions
of water. The product was dried for 48 h in vacuo at 50 °C
[19].
Experimental
Apparatus
All starting materials and reagents used were purchased from
Sigma Aldrich, Merck and used without further purification.
All aqueous solutions were prepared with deionized water that
had been passed through a Millipore milli Q Plus water puri-
FT-IR (cm−1): 3392 (O-H), 3165 (N-H), 2998 (CH2), 1659
1
(C = N), 1230 (C-O-C), 736 (CH, pyridine). H NMR
(CDCl3): δ = 6.95–7.13 (d, 2H), 7.77–7.88 (m, 2H), 8.08–
8.15 (d, 2H), 8.86–8.93 (dd, 2H), 8.97–9.03 (dd, 2H), 10
(OH), 13.5 (s, 1H).
1
fication system. H-NMR spectra were taken using a Varian
400-MHz Spectrometer. FT-IR spectra were recorded using a
Perkin Elmer Spectrum 100 FT-IR Spectrometer. Melting
points were determined by Büchi Melting Point B-540 instru-
ment. Elemental analyses were carried out using a LECO-
CHNS- 932 elementel analyser. UV–vis spectra were record-
ed on Perkin Elmer Lambda 25 UV–Vis Spectrometer. The
emission measurements were performed using a Perkin Elmer
LS 55 Luminescence Spectrometer. Thin layer chromatogra-
phy (TLC) was performed using silica gel on glass TLC plates
(silicagel H, type60, Merck).
3, 4-Bis(Prop-2-Ynyloxy)Benzaldehyde 3, 4-
Dihydroxybenzaldehyde (0.1 g, 0.72 mmol), 3-bromopropene
(0.2 g, 1.8 mmol), NaI (0.01 g, 0.072 mmol) and K2CO3 were
dissolved in 20 mL DMF. The solution was stirred for 3 h at
room temperature. The resulting crude product was filtered,
washed with water-brine and dried. It was purified with silica
gel column (n-hexane: ethylacetate, 20:1) [22].
4-((4-(1H-Imidazo[4,5-f][1,10]Phenanthroline-2-
yl)Phenoxy)Methyl)Benzaldehyde, BA-PPY To the solu-
tion of 4-(bromomethyl)benzaldehyde in 30 mL DMF,
4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenol
(0.15 g, 0.5 mmol) and K2CO3 (0.13 g, 1 mmol) were added.
The mixture was stirred for 36 h at 90 °C. Then cooled to
room temperature and 50 mL water as added to the solution.
The resulting crude product were filtered and washed with
cold water.
Method
1,10-Phenanthroline-5,6-dione [18], 4-(1H-imidazo[4,5-f][1,
10]phenanthroline-2-yl)phenol [19], [Ru(phen)2Cl2]·2H2O
[20], [Ru(bpy)2Cl2].H2O [21] and 3,4-bis(prop-2-
ynyloxy)benzaldehyde [22] were synthesized by the literature
methods. Other materials were commercially available and of
reagent grade. All of them were used without purification.
MP: 305 °C, MW: 430 g/mol, FT-IR (cm−1): 3049 (N-H),
1
Synthesis
1694 (C = O), 1208 (C-O-C), 804 (CH-pyridine). H-NMR
(DMSO-d6): δ (ppm) = 5.4 (s, 2H,O-CH2), 7.3–8.95 (m, 12H,
ArH), 9.2 (s, 2H, HC = N), 10.0 (s, 1H, HC = O), 13.75 (s, 1H,
−NH).
1,10-Phenantroline-5,6-Dione Phenanthroline (0.54 g,
3 mmol) was added into a solution of 60 % sulfuric acid
(7 mL). After the solid compound was dissolved, potassium
bromate (0.55 g, 3.3 mmol) was added in batches over a pe-
riod of half an hour. The mixture was stirred at room temper-
ature for 20 h. Then, the mixture was poured over ice and was
carefully neutralized to pH:7 using a saturated solution of
sodium hydroxide. The solution was then filtered, extracted
[ R u ( P h e n ) 2 ( 4 - ( ( 4 - ( 1 H - I m i d a z o [ 4 , 5 - f ] [ 1 ,
10]Phenanthroline-2-yl)Phenoxy)Methyl)Benzaldehyde)]
(ClO4)2, RuP(BA-PPY) cis-[Ru(phen)2Cl2] (0.069 g,
0.23 mmol) and BA-PPY (0.1 g, 0.23 mmol) were added to
20 ml methanol. The mixture was refluxed for 12 h under an

J Fluoresc
nitrogen atmosphere. The cooled reaction mixture was diluted
with water (20 ml) and filtered to remove solid impurities. The
complex was then separated from soluble impurities by pre-
cipitation with sodium perchlorate. The precipitated complex
was filtered and washed with water and dried. MP: > 399 °C,
MW: 1090 g/ mol, FT-IR (cm−1): 3068 (N-H), 1660 (C = N),
1049 (ClO4 ), 804 (CH-pyridine), 540 (M-N).
C51H34Cl2N8O10Ru, Elemetal Analysis; Calculated (Found):
C, 56.15 (55.7), H, 3.14 (3. 13), N, 10.27 (9.98).
N). C68H45Cl2N9O9Ru, Elemetal Analysis; Calculated
(Found): C, 62.63 (61.90), H, 3.48 (3.20), N, 9.67 (8.99).
[Ru(Bpy)2 ((E)-N-(4-((4-(1H-Imidazo[4,5-f][1,
10]Phenanthroline-2-yl)Phenoxy)Methyl) Benzylidene)-
P y r e n e - 4 - A m i n e ) ] ( C l O 4 ) 2 , R u B ( P R - P P Y )
cis-[Ru(bpy)2Cl2] (0.07 g,0.15 mmol) and PR-PPY (0.1 g,
0.15 mmol) were added to 20 ml methanol. The mixture was
refluxed for 12 h under an nitrogen atmosphere. The cooled
reaction mixture was diluted with water (20 ml) and filtered to
remove solid impurities. The complex was then separated
from soluble impurities by precipitation with sodium perchlo-
rate. The precipitated complex was filtered and washed with
water and dried.
[Ru(Bpy)2(4-((4-(1H-Imidazo[4,5-f][1,10]Phenanthroline-
2-yl)Phenoxy)Methyl)Benzaldehyde)] (ClO4)2, RuB(BA-
PPY) cis-[Ru(bpy)2Cl2] (0.063 g, 0.23 mmol) and BA-PPY
(0.1 g, 0.23 mmol) were added to 20 ml methanol. The mix-
ture was refluxed for 12 h under an nitrogen atmosphere. The
cooled reaction mixture was diluted with water (20 ml) and
filtered to remove solid impurities. The complex was then
separated from soluble impurities by precipitation with sodi-
um perchlorate. The precipitated complex was filtered and
washed with water and dried. MP: > 399 °C, MW: 1042 g/
mol, FT-IR (cm−1): 3073 (N-H), 1611 (C = N), 1073 (ClO4),
802 (CH-piridin), 540 (M-N). C47H34Cl2N8O10Ru, Elemetal
Analysis; Calculated (Found): C, 54.13 (54.03), H, 3.29
(3.19), N, 10.75 (9.99).
MP:> 399 °C, MW: 1256 g/mol, FT-IR (cm−1): 3027 (N-
H), 1604 (C = N), 1060 (ClO4), 721 (CH-pyridine), 580 (M-
N). C64H45Cl2N9O9Ru, Elemetal Analysis; Calculated
(Found): C, 61.20 (60.85), H, 3.61 (3.26), N, 10.04 (9.93).
(E)-N-(4-((4-(1H-Imidazo[4,5-f][1,10]Phenanthroline-2-
yl)Phenoxy)Methyl)Benzylidene)-1,10-Phenanthroline-
5amine, FN-PPY To a stirred solution of 1,10-
phenanthroline-5amine (0.02 g, 0.11 mmol) 25 mL methanol,
the solution of BA-PPY (0.05 g, 0.11 mmol) in 5 mL metha-
nol was added to this mixture and continued to stirring for 36 h
at 70 °C. The resulting crude product were filtered and recrys-
tallized from methanol.
(E)-N-(4-((4-(1H-Imidazo[4,5-f][1,10]Phenanthroline-2-
yl)Phenoxy)Methyl)Benzylidene)-Pyrene-4-Amine, PR-
PPY To a stirred solution of 1-pyrene(methylamine) hydro-
chloride (0.062 g, 0.23 mmol) i 25 mL methanol, 10 mL
tirethylamine was added. After half and hour, the solution of
BA-PPY (0.1 g, 0.23 mmol) in 5 mL methanol was added to
this mixture and continued to stirring for 36 h at 70 °C. The
resulting crude product were filtered and recrystallized from
methanol.
MP: 225 °C, MW: 607 g/mol, FT-IR (cm−1): 3024 (N-H),
1
1608 (C = N), 1242(C-O-C), 802 (CH-pyridine). H NMR
(DMSO-d6): δ (ppm) = 5.15 (s, 2H, O-CH2), 7.2–9.0 (m,
21H, ArH), 8.9 (s, 1H, HC = N), 13.6 (b, 1H, −NH).
[(Ru(Phen)2)2((E)-N-(4-((4-(1H-Imidazo[4,5-f][1,
10]Phenanthroline-2-yl)Phenoxy)Methyl) Benzylidene)-
1,10-Phenanthroline-5amine)] (ClO4)4, RuP(FN-PPY)
cis-[Ru(phen)2Cl2] (0.17 g, 0.32 mmol) and FN-PPY (0.1 g,
0.16 mmol) were added to 20 ml methanol. The mixture was
refluxed for 12 h under an nitrogen atmosphere. The cooled
reaction mixture was diluted with water (20 ml) and filtered to
remove solid impurities. The complex was then separated
from soluble impurities by precipitation with sodium perchlo-
rate. The precipitated complex was filtered and washed with
water and dried.
MP: 306 °C, MW: 643 g/mol, FT-IR (cm−1): 3044 (N-H),
1
1607 (C = N), 1250 (C-O-C), 813 (CH-pyridine). H-NMR
(DMSO-d6): δ (ppm) = 5.2 (s, 2H, O-CH2), 5.4 (s, 2H, CH2-
N), 7.2–9.1 (m, 22H, ArH), 9.2 (s, 2H, HC = N), 13.8 (b, 1H,
−NH).
[Ru(Phen)2((E)-N-(4-((4-(1H-Imidazo[4,5-f][1,
10]Phenanthroline-2-yl)Phenoxy)Methyl) Benzylidene) -
P y r e n e - 4 - A m i n e ) ] ( C l O 4 ) 2 , R u P ( P R - P P Y )
cis-[Ru(phen)2Cl2] (0.082 g, 0.15 mmol) and PR-PPY
(0.1 g, 0.15 mmol) were added to 20 ml methanol. The mix-
ture was refluxed for 12 h under an nitrogen atmosphere. The
cooled reaction mixture was diluted with water (20 ml) and
filtered to remove solid impurities. The complex was then
separated from soluble impurities by precipitation with sodi-
um perchlorate. The precipitated complex was filtered and
washed with water and dried.
MP:> 399 °C, MW: 1927 g/mol, FT-IR (cm−1): 3402 (N-
H), 1650 (C = N), 1033 (ClO4), 750 (CH-pyridine), 580 (M-
N). C87H57Cl4N15O17Ru2, Elemetal Analysis; Calculated
(Found): C, 54.19 (54.01), H, 2.98 (2.10), N, 10.89 (9.94).
[(Ru(Bpy)2)2((E)-N-(4-((4-(1H-Imidazo[4,5-f][1,
10]Phenanthroline-2-yl)Phenoxy)Methyl) Benzylidene) -
1,10-Phenanthroline-5amine)] (ClO4)4, RuB(FN-PPY)
cis-[Ru(bpy)2Cl2] (0.16 g, 0.32 mmol) and FN-PPY (0.1 g,
0.16 mmol) were added to 20 ml methanol. The mixture was
MP:> 399 °C, MW: 1303 g/mol, FT-IR (cm−1): 3131 (N-
H), 1604 (C = N), 1060 (ClO4), 711 (CH-pyridine), 580 (M-

J Fluoresc
refluxed for 12 h under an nitrogen atmosphere. The cooled
reaction mixture was diluted with water (20 ml) and filtered to
remove solid impurities. The complex was then separated
from soluble impurities by precipitation with sodium perchlo-
rate. The precipitated complex was filtered and washed with
water and dried.
C
40H29BrCl2N8O8Ru, Elemetal Analysis; Calculated
(Found): C, 47.97 (46.70), H, 2.92 (2.89), N, 11.19 (11.23).
2-(4-(Azidomethyl)Phenyl)-1H-Imidazo[4,5-f][1,
10]Phenanthroline, N3-PPY To the solution of BR-PPY
(0.1 g, 0.25 mmol) in 20 mL DMF sodium azide (0.021 g,
0.32 mmol) was added. The mixture was stirred for 36 h at
90 °C. Then cooled to room temperature and 200 mL water
was added to the solution, extracted with DCM. Then organic
phase was collected and dried with Na2SO4. Solvent was re-
moved by evaporation and resulting crude yellow product
were collected.
MP:> 399 °C, MW: 1831 g/mol, FT-IR (cm−1): 3310 (N-
H), 1606 (C = N), 1069 (ClO4), 722 (CH-pyridine), 580
(M-N). C79H57Cl4N15O17Ru2, Elemetal Analysis;
Calculated (Found): C, 51.78 (51.60), H, 3.14 (3.09), N,
11.47 (11.09).
2-(4-(Bromomethyl)Phenyl)-1H-Imidazo[4,5-f][1,
10]Phenanthroline, BR-PPY A mixture of 1,10-
phenanthroline-5,6-dione (0.25 g, 1.2 mmol), ammonium ac-
etate (2.6 g, 1.2 mmol), 4-(bromomethyl) benzaldehyde
(0.25 g, 0.46 mmol) and30 mL glacial acetic acid were
refluxed for 48 h and then poured in 200 mL of water. The
solution was neutralized with ammonia to pH:7 and cooled to
room temperature. The precipitate was collected and washed
with water. The crude yellow product was dried under vacuo.
MP: 193 °C, MW: 388 g/mol, FT-IR (cm−1): 3081 (N-H),
1744 (C = N), 689 (C-Br), 1H-NMR (DMSO-d6): δ
(ppm) = 5.15 (s, 2H, Br-CH2), 7.15–9.0 (m, 8H, ArH), 9.1
(s,2H, HC = N), 13.75 (b, −NH).
MP: 277 °C, MW: 351 g/ mol, FT-IR (cm−1): 3081 (N-H),
1
2150 (N = N = N), 1735 (C = N). H-NMR (DMSO-d6): δ
(ppm) = 2.6 (s, 2H, N3-CH2), 7.5–9.0 (m, 8H, ArH), 8.98
(s,2H, HC = N), 13.75 (b, 1H, −NH).
[Ru(Phen)2(2-(4-(Azidomethyl)Phenyl)-1H-Imidazo[4,5-
f][1,10]Phenanthroline)] (ClO4)2, RuP(N3-PPY)
cis-[Ru(phen)2Cl2] (0.08 g, 0.28 mmol) and N3-PPY (0.1 g,
0.28 mmol) were added to 20 ml methanol. The mixture was
refluxed for 12 h under an nitrogen atmosphere. The cooled
reaction mixture was diluted with water (30 ml) and filtered to
remove solid impurities. The complex was then separated
from soluble impurities by precipitation with sodium perchlo-
rate. The precipitated complex was filtered and washed with
water and dried.
[Ru(Phen)2 (2-(4-(Bromomethyl)Phenyl)-1H-Imidazo[4,5-
f][1,10]Phenanthroline)] (ClO4)2, RuP(BR-PPY)
cis-[Ru(phen)2Cl2] (0.076 g, 0.25 mmol) and BR-PPY
(0.1 g, 0.25 mmol) were added to 20 ml methanol. The mix-
ture was refluxed for 12 h under an nitrogen atmosphere. The
cooled reaction mixture was diluted with water (30 ml) and
filtered to remove solid impurities. The complex was then
separated from soluble impurities by precipitation with sodi-
um perchlorate. The precipitated complex was filtered and
washed with water and dried.
MP:> 399 °C, MW: 1011 g/ mol, FT-IR (cm−1): 3350 (N-
H), 1601 (C = N), 1038 (ClO4), 723 (CH-pyridine), 502 (M-
N). C44H29Cl2N11O8Ru, Elemetal Analysis; Calculated
(Found): C, 52.23 (52.24), H, 2.89 (2.84), N, 15.23 (14.99).
[Ru(Bpy)2(2-(4-(Azidomethyl)Phenyl)-1H-Imidazo[4,5-
f][1,10]Phenanthroline)] (ClO4)2, RuB(N3-PPY)
cis-[Ru(bpy)2Cl2] (0.07 g, 0.28 mmol) and N3-PPY (0.1 g,
0.28 mmol) were added to 20 ml methanol. The mixture was
refluxed for 12 h under an nitrogen atmosphere. The cooled
reaction mixture was diluted with water (30 ml) and filtered to
remove solid impurities. The complex was then separated
from soluble impurities by precipitation with sodium perchlo-
rate. The precipitated complex was filtered and washed with
water and dried.
MP:> 399 °C, MW: 1047 g/mol, FT-IR (cm−1): 3480 (N-
H), 1633 (C = N), 1085 (ClO4), 715 (CH-pyridine), 530 (M-
N). C44H29BrCl2N8O8Ru, Elemetal Analysis; Calculated
(Found): C, 50.35 (51.23), H, 2.78 (2.40), N, 10.68 (10.30).
[Ru(Bpy)2(2-(4-(Bromomethyl)Phenyl)-1H-Imidazo[4,5-
f][1,10]Phenanthroline)](ClO4)2, RuB(BR-PPY)
cis-[Ru(bpy)2Cl2] (0.07 g, 0.25 mmol) and BR-PPY (0.1 g,
0.25 mmol) were added to 20 ml methanol. The mixture was
refluxed for 12 h under an nitrogen atmosphere. The cooled
reaction mixture was diluted with water (30 ml) and filtered to
remove solid impurities. The complex was then separated
from soluble impurities by precipitation with sodium perchlo-
rate. The precipitated complex was filtered and washed with
water and dried.
MP:> 399 °C, MW: 963 g/ mol, FT-IR (cm−1): 3501 (N-H),
1602 (C = N), 1084 (ClO4), 726 (CH-pyridine), 502 (M-N).
C40H29Cl2N11O8Ru, Elemetal Analysis; Calculated (Found):
C, 49.85 (50.02), H, 3.03 (3.01), N, 15.99 (14.89).
3,4-Bis[(4-(Methoxy)-1,2,3-Triazole)-1-Methylphenyl)-
1H-Imidazo[4,5-f][1,10]Phenanthroline)] Benzaldehyde,
BA-DIPPY To a mixture of CHCl3:MeOH:H2O (10:1:1),
3,4-bis(prop-2-ynyloxy)benzaldehyde (0.026 g, 0.074 mmol)
and N3-PPY (0.035 g, 0.16 mmol) were added. Then sodium
ascorbate (0.0045 g, 0.022 mmol) was added to this mixture
MP:> 399 °C, MW: 999 g/mol, FT-IR (cm−1): 3402 (N-H),
1610 (C = N), 1090 (ClO4), 716 (CH-pyridine), 530 (M-N).

J Fluoresc
and stirred for 15 min., followed by the addition of CuSO4
(0.0018 g, 0.011 mmol). The heterogenous mixture was
stirred vigorously for 120 h at room temperature. After the
reaction completed, the solvents were evaporated and the res-
idue was extracted with CHCl3-water. The combined organic
phase was concentrated, washed with ethylacetate and dried
under vacuo.
4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
y l ) ph e no x y) m e t h y l ) be n za l d e hy d e ( B A - P P Y )
polypyridine ligand is a starting material for PR-PPY
and FN-PPY schiff base polypyridine ligands (Fig. 1).
BR-PPY was prepared by the condensation reaction be-
tween one equivalent of 1,10-phenanthroline-5,6-dione
and one equivalent of 4-(bromomethyl) benzaldehyde
in the presence of an excess of ammonium acetate in
refluxing acetic acid. N3-PPY was prepared for the syn-
thesis of triazole containing 3,4-bis[(4-(metoxy)-1,2,3-
triazole)1-methylphenyl)-1H-imidazo[4,5-f][1,
10]phenanthroline)]benzaldehyde (BA-DIPPY) polypyridine
ligand (Fig. 2).
E.N.: 325 °C, MA: 916 g/ mol, FT-IR (cm−1): 3243 (N-H),
2923 (C-H), 2160 (N = N), 1725 (C = O). 1H-NMR (DMSO-
d6): δ (ppm) = 4.8 (s, 4H, O-CH2), 7.12–9.0 (m, 30H, ArH),
9.81 (s, 1H, HC = O), 13.75 (b, 2H, −NH).
Result and Discussion
The heteroleptic mono- and dinuclear complexes;
[Ru(phen)2(4-((4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-
y l ) p h e n o x y ) m e t h y l ) b e n z a l d e h y d e ) ] ( C l O 4 ) 2 ,
[Ru(bpy)2(4-((4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-
yl)phenoxy)methyl)benzaldehyde)] (ClO4)2, [Ru(phen)2((E)-
N-(4-((4-(1H-imidazo [4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-pyrene-4-amine)] (ClO4)2,
[Ru(bpy)2 ( (E)-N-(4-((4-(1H-imidazo[4,5-f][1,
10]phenanthroline-2-yl)phenoxy)methyl)benzylidene)-
pyrene-4-amine)] (ClO4)2, [(Ru(phen)2)2((E)-N-(4-((4-(1H-
imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)
methyl)benzylidene)-1,10-phenanthroline-5amine)] (ClO4)4,
[(Ru(bpy)2)2((E)-N-(4-((4-(1H-imidazo[4,5-f][1,
10]phenanthroline-2-yl)phenoxy)methyl)benzylidene)-1,10-
phenanthroline-5amine)] (ClO4)4, [Ru(phen)2(2-
(4-(bromomethyl)phenyl)-1H-imidazo[4,5-f][1,
10]phenanthroline)] (ClO4 )2 , [Ru(bpy)2 (2-(4-
( b r o m o m e t h y l ) p h e n y l ) - 1 H - i m i d a z o [ 4 , 5 - f ] [ 1 ,
10]phenanthroline)] (ClO4)2, [Ru(phen)2(2-(4-(azido
m e t h y l ) p h e n y l ) - 1 H - i m i d a z o [ 4 , 5 - f ] [ 1 ,
10]phenanthroline)](ClO4 )2 , [Ru(bpy)2 (2-(4-
( a z i d o m e t h y l ) p h e n y l ) - 1 H - i m i d a z o [ 4 , 5 - f ] [ 1 ,
10]phenanthroline)] (ClO4)2 were prepared by the reaction of
the performed mono- and dipodal imidazo[4,5-f][1,10]-
phenanthroline-cored ligands and [Ru(phen)2Cl2] and
[Ru(bpy)2Cl2].2H2O in methanol (Fig. 3).
Synthesis and Characterization
In this study novel polypyridine ligands and Ruthenium(II)-
bridged complexes were synthesized. Firstly, 4-
((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzaldehyde (BA-PPY) polypyridine li-
gand was synthesized. Then schiff base polypyridine ligands;
(E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-pyrene-4-amine (PR-PPY),
(E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-1,10-phenanthroline-
5amine (FN-PPY) and different substitued ligands;
2-(4-(bromomethyl)phenyl)-1H-imidazo[4,5-f][1,
10]phenanthroline (BR-PPY), 2-(4-(azidomethyl)phenyl)-
1H-imidazo[4,5-f][1,10]phenanthroline (N3-PPY) were syn-
thesized. Triazole containing polypyridine ligand 3,4-
bis[(4-(metoxy)-1,2,3-triazole)1-methylphenyl)-1H-
imidazo[4,5-f][1,10]phenanthroline)]benzaldehyde (BA-
DIPPY) was synthesized as a part of ‘click chemistry’. An
outline of the synthesis of the polypyridine ligands were pre-
sented in Figs. 1 and 2. Except BA-DIPPY, Ruthenium(II)
complexes of the ligands were synthesized with
[Ru(phen)2Cl2] and [Ru(bpy)2Cl2] and the synthesis of
‘bridged complexes’ were completed.
Fig. 1 Synthesis sheme of (PR-PPY) ve (FN-PPY) schiff base polypyridine ligands

J Fluoresc
Fig. 2 Synthesis sheme of BR-PPY, N3-PPY, BA-DIPPY different substitued polypyridine ligands
The complexes were isolated as perchlorate salts and stable
in air and in solution. All the ligands and Ruthenium(II)-
bridged complexes were synthesized originally and character-
ized by 1H-NMR spectroscopy, FT-IR spectroscopy,
Elemental analysis and TG/DTA analysis. Their aborsption
and emission studies were performed in acetonitrile medium
by UV-Vis Spectrometer and Luminescence Spectrometer.
The 1H-NMR data and important FT-IR frequencies were giv-
en in experimental part and Tables 1 and 2.
phenanthroline nitrogen atoms to Ruthenium(II) leads to the
electron deficiency of the phenanthroline group.
In the FT-IR spectra of the complex RuP(BA-PPY) the
peak at 3068 cm−1 comprises the both N-H and C-H bands.
The peak at 1660 cm−1 belongs to the C = O stretching and the
peak at 804 cm−1 belongs to the pyridine groups. In addition,
The proof peak of the complexation observed at 540 cm−1
which could be assigned to Ru(II)-N stretching. A strong
bands at 1049 cm−1 could be assigned to the counter anion
−
4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzaldehyde (BA-PPY) aldehyde-
ended polypyridine ligand was synthesized originally. The
1H-NMR spectrum of the monopodal ligand BA-PPY shows
the chemical shifts at 8.95 and 8.2 ppm are assigned to the
protons of the phenanthroline ring. The chemical shifts around
7.8 ppm are assigned to the protons of the aromatic groups.
Aldehyde HC = O band observed at 10.0 ppm. –NH group
shows a chemical shift at 13.75 ppm and CH2-O group shows
a chemical shift at 5.4 ppm. In the FT-IR spectra of the ligand
BA-PPY the peak at 3049 cm−1 comprises the both N-H and
C-H bands. The peak at 1694 cm−1 belongs to the C = O
stretching, the peak at 1208 cm−1 belongs to C-O-C ether
bond and the peak at 804 cm−1 belongs to the pyridine groups.
Upon Ruthenium(II) coordination, obtained complexes of
this ligand are [Ru(phen)2(4-((4-(1H-imidazo[4,5-f][1,
10]phenanthroline-2-yl)phenoxy)methyl)benzaldehyde)]
( C l O 4 ) 2 , ( R u P ( B A - P P Y ) ) a n d [ R u ( b p y ) 2 ( 4 -
((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzaldehyde)] (ClO4)2, (RuB(BA-
PPY)). In the FT-IR spectra, the chemical shifts of the ligands
shifted obviously. This is because of the coordination of
ClO4 . In the FT-IR spectra of the complex RuB(BA-PPY) the
peak at 3073 cm−1 comprises the both N-H and C-H bands.
The peak at 1611 cm−1 belongs to the C = O stretching and the
peak at 802 cm−1 belongs to the pyridine groups. The proof
peak of the complexation observed at 540 cm−1 which could
be assigned to Ru(II)-N stretching. A strong bands at
1073 cm−1 could be assigned to the counter anion ClO4 .
−
(E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-pyrene-4-amine (PR-PPY),
fluorescent Schiff base polypyridine ligand was synthesized
1
originally. The H-NMR spectrum of the monopodal ligand
PR-PPY shows the chemical shifts at 9.1 and 8.25 ppm are
assigned to the protons of the phenanthroline ring. The chem-
ical shifts around 7.90 ppm are assigned to the protons of the
aromatic groups. Schiff base imine HC = N band observed at
9.20 ppm. –NH group shows a chemical shift at 13.8 ppm.
CH2-O and CH2-N groups show the chemical shifts at 5.2 and
5.4 ppm, respectively. In the FT-IR spectra of the ligand PR-
PPY the peak at 3044 cm−1 comprises the both N-H and C-H
bands. The peak at 1607 cm−1 belongs to the C = N stretching,
the peak at 1250 cm−1 belongs to C-O-C ether bond and the
peak at 813 cm−1 belongs to the pyridine groups.

J Fluoresc
Fig. 3 The structure of Ruthenium(II)-bridged polypyridine complexes
In the FT-IR spectra of the complex [Ru(phen)2((E)-
N-(4-((4-(1H-imidazo [4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-pyrene-4-amine)] (ClO4)2,
RuP(PR-PPY), the peak at 3131 cm−1 comprises N-H bands
and the peak at 2950 cm−1 comprises C-H bands. The peak at
1604 cm−1 belongs to the C = N stretching and the peak at
Table 1 1H-NMR characteristic chemical shift data of the ligands (ppm)
No
Ligand
Phen
Phenyl
O-CH2
Br-CH2
N3-CH2
C = O
10.0
N-CH2
5.40
C = N
N-H
1
2
3
4
5
6
BA-PPY
PR-PPY
FN-PPY
BR-PPY
N3-PPY
BA-DIPPY
8.95, 8.20
9.1, 8.25
7.84
5.40
5.20
5.15
13.75
13.80
13.60
13.75
13.75
13.75
7.90, 7.55
7.80, 7.30
7.80, 7.60
7.80, 7.50
8.10, 7.25
9.20
8.90
9.00, 8.15
8.90, 8.40
9.00, 8.30
8.85, 8.30
5.15
2.60
4.80
9.81

J Fluoresc
N = N = N
Table 2 FT-IR characteristic frequencies of the ligands and complexes (cm−1
)
No
Ligand-Complexes
N-H
C = N
C = O
1694
Pyridine
M-N
ClO4
C-O-C
C-Br
689
1
BA-PPY
3049
3044
3024
3081
3081
3243
3068
3073
3131
3027
3402
3310
3480
3402
3350
3501
804
813
802
800
804
809
804
802
711
721
750
722
715
716
723
726
1208
1250
1242
2
PR-PPY
1607
1608
1744
1735
3
FN-PPY
4
BR-PPY
5
N3-PPY
2150
6
BA-DIPPY
RuP(BA-PPY)
RuB(BA-PPY)
RuP(PR-PPY)
RuB(PR-PPY)
RuP(FN-PPY)
RuB(FN-PPY)
RuP(BR-PPY)
RuB(BR-PPY)
RuP(N3-PPY)
RuB(N3-PPY)
1725
1660
1611
1225
7
540
540
580
580
580
580
530
530
502
502
1049
1073
1060
1060
1033
1069
1085
1090
1038
1084
8
9
1604
1604
1650
1606
1633
1610
1601
1602
10
11
12
13
14
15
16
690
692
2010
2015
711 cm−1 belongs to the pyridine groups. In addition, The
proof peak of the complexation observed at 580 cm−1 which
could be assigned to Ru(II)-N stretching. A strong bands at
5amine)] (ClO4)4, RuP(FN-PPY), the peak at 3402 cm−1 com-
prises N-H bands and the peak at 2922 cm−1 comprises C-H
bands. The peak at 1650 cm−1 belongs to the C = N stretching
and the peak at 750 cm−1 belongs to the pyridine groups. In
addition, The proof peak of the complexation observed at
580 cm−1 which could be assigned to Ru(II)-N stretching. A
strong bands at 1033 cm−1 could be assigned to the counter
anion ClO4−. In the FT-IR spectra of the complex
[(Ru(bpy)2)2((E)-N-(4-((4-(1H-imidazo[4,5-f][1,
10]phenanthroline-2-yl)phenoxy)methyl)benzylidene)-1,10-
phenanthroline-5amine)] (ClO4)4, RuB(FN-PPY) the peak at
3310 cm−1 comprises N-H bands and the peak at 2921 cm−1
comprises C-H bands. The peak at 1606 cm−1 belongs to the
C = N stretching and the peak at 722 cm−1 belongs to the
pyridine groups. In addition, The proof peak of the complex-
ation observed at 580 cm−1 which could be assigned to Ru(II)-
N stretching. A strong bands at 1069 cm−1 could be assigned
1060 cm−1 could be assigned to the counter anion ClO4 . In
−
the FT-IR spectra of the complex [Ru(bpy)2((E)-
N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-pyrene-4-amine)] (ClO4)2,
RuB(PR-PPY), the peak at 3027 cm−1 comprises N-H bands
and the peak at 2980 cm−1 comprises C-H bands. The peak at
1604 cm−1 belongs to the C = N stretching and the peak at
721 cm−1 belongs to the pyridine groups. In addition, The
proof peak of the complexation observed at 580 cm−1 which
could be assigned to Ru(II)-N stretching. A strong bands at
1060 cm−1 could be assigned to the counter anion ClO4 .
−
(E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-1,10-phenanthroline-
5amine (FN-PPY), fluorescent Schiff base polypyridine li-
1
−
gand was synthesized originally. The H-NMR spectrum of
to the counter anion ClO4 .
the monopodal ligand FN-PPY shows the chemical shifts at
9.0 and 8.15 ppm are assigned to the protons of the
phenanthroline ring. The chemical shifts around 7.8 ppm are
assigned to the protons of the aromatic groups. Schiff base
imine HC = N band observed at 8.9 ppm. –NH group shows
a chemical shift at 13.6 ppm. CH2-O group shows the chem-
ical shift at 5.15 ppm, respectively. In the FT-IR spectra of the
ligand FN-PPY the peak at 3024 cm−1 comprises the both N-
H and C-H bands. The peak at 1608 cm−1 belongs to the C = N
stretching, the peak at 1242 cm−1 belongs to C-O-C ether
bond and the peak at 802 cm−1 belongs to the pyridine groups.
In the FT-IR spectra of the complex [(Ru(phen)2)2((E)-
N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-
yl)phenoxy)methyl)benzylidene)-1,10-phenanthroline-
2-(4-(Bromomethyl)phenyl)-1H-imidazo[4,5-f][1,
10]phenanthroline, BR-PPY, bromomethyl-substitued
polypyridine ligand was synthesized originally. The H-NMR
1
spectrum of the monopodal ligand BR-PPY shows the chemical
shifts at 8.9 and 8.4 ppm are assigned to the protons of the
phenanthroline ring. The chemical shifts around 7.8 ppm are
assigned to the protons of the aromatic groups. –NH group
shows a chemical shift at 13.75 ppm and CH2-Br group shows
a chemical shift at 5.15 ppm. In the FT-IR spectra of the ligand
BR-PPY the peak at 3081 cm−1 comprises the both N-H and C-
H bands. The peak at 1744 cm−1 belongs to the C = N stretching,
and the peak at 800 cm−1 belongs to the pyridine groups.
In the FT-IR spectra of the complex [Ru(phen)2(2-
(4-(bromomethyl)phenyl)-1H-imidazo[4,5-f][1,

J Fluoresc
Fig. 4 1H-NMR spectrum of BA-DIPPY
1
10]phenanthroline)] (ClO4)2, RuP(BR-PPY), the peak at
3480 cm−1 comprises the both N-H and C-H bands. The peak
at 1633 cm−1 belongs to the C = N stretching and the peak at
715 cm−1 belongs to the pyridine groups. In addition, The proof
peak of the complexation observed at 530 cm−1 which could be
assigned to Ru(II)-N stretching. A strong bands at 1085 cm−1
polypyridine ligand was synthesized originally. The H-
NMR spectrum of the monopodal ligand N3-PPY shows the
chemical shifts at 9.0 and 8.3 ppm are assigned to the protons
of the phenanthroline ring. The chemical shifts around
7.78 ppm are assigned to the protons of the aromatic groups.
–NH group shows a chemical shift at 13.70 ppm and CH2-N3
group shows a chemical shift at 2.6 ppm. In the FT-IR spectra
of the ligand N3-PPY the peak at 3080 cm−1 comprises the
both N-H and C-H bands. The peak at 2150 cm−1 belongs to
the N = N stretching and the peak at 1735 cm−1 belongs to the
C = N stretching, and the peak at 804 cm−1 belongs to the
pyridine groups.
In the FT-IR spectra of the complex [Ru(phen)2(2-
(4-(azidomethyl)phenyl)-1H-imidazo[4,5-f][1,
10]phenanthroline)] (ClO4)2, RuP(N3-PPY), the peak at
3350 cm−1 comprises the both N-H and C-H bands. The peak
at 1601 cm−1 belongs to the C = N stretching and the peak at
−
could be assigned to the counter anion ClO4 . In the FT-IR
spectra of the complex [Ru(bpy)2(2-(4-(bromomethyl)phenyl)-
1H-imidazo[4,5-f][1,10]phenanthroline)] (ClO4)2, RuB(BR-
PPY) the peak at 3402 cm−1 comprises the both N-H and C-H
bands. The peak at 1610 cm−1 belongs to the C = N stretching
and the peak at 716 cm−1 belongs to the pyridine groups. The
proof peak of the complexation observed at 530 cm−1 which
could be assigned to Ru(II)-N stretching. A strong bands at
1090 cm−1 could be assigned to the counter anion ClO4 .
−
2-(4-(azidomethyl)phenyl)-1H-imidazo[4,5-f][1,
10]phenanthroline (N3-PPY), azidomethyl-substitued
Diagram 1 TG/ DTA diagram of RuP(PR-PPY) polypyridine complex

J Fluoresc
Diagram 2 TG/ DTA diagram of RuB(PR-PPY) polypyridine complex
723 cm−1 belongs to the pyridine groups. In addition, The
proof peak of the complexation observed at 502 cm−1 which
could be assigned to Ru(II)-N stretching. A strong bands at
3501 cm−1 comprises the both N-H and C-H bands. The peak
at 1602 cm−1 belongs to the C = N stretching and the peak at
726 cm−1 belongs to the pyridine groups. The proof peak of
the complexation observed at 502 cm−1 which could be
assigned to Ru(II)-N stretching. A strong bands at
1038 cm−1 could be assigned to the counter anion ClO4 . In
−
the FT-IR spectra of the complex [Ru(bpy)2
(2-(4-(azidomethyl)phenyl)-1H-imidazo[4,5-f][1,
10]phenanthroline)] (ClO4)2, RuB(BA-PPY) the peak at
1084 cm−1 could be assigned to the counter anion ClO4 .
−
3,4-bis[(4-(metoxy)-1,2,3-triazole)1-methylphenyl)-1H-
imidazo[4,5-f][1,10]phenanthroline)] benzaldehyde (BA-
DIPPY) aldehyde-ended triazole containing polypyridine li-
gand was synthesized originally as a part of ‘click chemistry’.
1
As seen in Fig. 4, the H-NMR spectrum of the monopodal
ligand BA-DIPPY shows the chemical shifts at 8.85 and
8.30 ppm are assigned to the protons of the phenanthroline
ring. The chemical shifts around 8.10–7.25 ppm are assigned
to the protons of the aromatic groups. Aldehyde HC = O band
observed at 9.81 ppm. –NH group shows a chemical shift at
13.75 ppm and CH2-O group shows a chemical shift at
4.8 ppm. In the FT-IR spectra of the ligand BA-DIPPY the
peak at 3243 cm−1 comprises the both N-H and C-H bands.
The peak at 1725 cm−1 belongs to the C = O stretching, the
peak at 1225 cm−1 belongs to C-O-C ether bond and the peak
at 809 cm−1 belongs to the pyridine groups.
Magnetic and Thermal Properties
The magnetic susceptibility measurements of the Ruthenium(II)-
bridged polypyridine complexes shows that all the complexes
have diamagnetic property. It is seen that the complexes are
represented by the electronic structure of t2g6eg0. The magnetic
data for the complexes show good harmony with the high spin d6
metal ion in an octahedral structure [23].
Fig. 5 Electronic absorption spectra of pyrene-appended polypyridine
ligand PR-PPY and Ruthenium(II) complexes in acetonitrile medium at
room temperature

J Fluoresc
ligands of the Ruthenium complexes. The residues were car-
bon black, some metal oxides and chlorides as RuO2, Ru2O3,
RuCl3 [24]. The observed weight losses for all complexes are
in good harmony with the calculated values.
Photophysical Properties
Electronic Absorption Spectra
The Uv-Vis absorption spectra of polypyridine ligands and
their Ruthenium(II)-bridged complexes have been recorded
in acetonitrile solution, at a working concentration of
1 × 10−6 mol/L between 200 and 800 nm. The ligand PR-
PPY and the complexes RuP(PR-PPY) and RuB(PR-PPY)
exhibit absorption bands in the UV region at 200–300 nm
and the ligands FN-PPY and the complexes RuP(FN-PPY)
and RuB(FN-PPY) exhibit absorption bands at 200–270 nm.
These bands are attributed to intraligand π–π* transitions
(ILCT) centered on the 2,2-bipyridine / 1,10-phenanthroline
ligands. The shoulders appearing at 328–345 nm for the com-
plexes of PR-PPY ligand and 276–324 nm for the complexes
of FN-PPY ligand are attributed to the imidazo[4,5-f][1,
10]phenanthroline-centered transition. The complexes
RuP(PR-PPY), RuB(PR-PPY, RuP(FN-PPY) and RuB(FN-
PPY) exhibit a broad absorption bands at 485, 475, 476, and
453 nm, respectively, assignable to the spin-allowed MLCT
(dπ–π*) transition (Figs. 5 and 6).
Maximum wavelenghts (λmax) and maximum absorbance
values (Amax) and calculated molar absorptivity values (ɛ) are
given in Table 3, (ɛ = Amax/l.C (l = 1 cm) for the Podal ligands
and complexes (a) and for the Schiff base ligand and com-
plexes. According to the molar absorptivity values, pyrene
and phenanthroline chromophore-appended Schiff base com-
pounds have strong molar absorptivity.
The singlet excited state of a metal-to-ligand charge trans-
fer transition (MLCT) consists of overlapping
dπ(Ru)-π*(bpy) / dπ(Ru)-π*(L) components. The MLCT
Fig. 6 Electronic absorption spectra of phenanthroline-appended
polypyridine ligand FN-PPY and Ruthenium(II) complexes in
acetonitrile medium at room temperature
The complexes RuP(PR-PPY), RuB(PR-PPY) have also
been thermally investigated and their plausible degradation
schemes are presented in Diagram 1 and 2. The thermograms
of the complexes show about five-step weight losses at the
temperature 40 to 1000 °C. The first weight loss at 50 to
170 °C was attributed to the removal of physically adsorbed
water, the second region between 250 to 350 °C was due to
removal of coordinated water. The third region between 250 to
500 °C was due to the combustion of amine and oxygen-
carrying functionalities, those not used for attachment of the
Ruthenium(II) complex. The forth region at 400 to 650 °C
was related to the perchlorate removal. And fifth region at
450 to 900 °C was attributed to the decomposition of the
Table 3 Maximum wavelenghts
(a)
(λmax) and maximum absorbance
values (Amax) and calculated
molar absorptivity values (ɛ) of
the Podal ligands and complexes
(1 × 10−4 M) (a) and Schiff base
ligand and complexes
λ
max (278 nm)
ɛ (M−1.cm−1
1184
)
λ
max (265 nm)
ɛ (M−1.cm−1
1001
)
O-DIPPY
P-DIPPY
TZ-PPY
(b)
0.1184
0.1166
0.1506
RuP(O-DIPPY)
RuP(P-DIPPY)
RuP(TZ-PPY)
0.1001
0.1056
0.1193
1166
1056
1506
1193
(1 × 10−6 M) (b) in acetonitrle
medium
λ
max (275 nm)
ɛ (M−1.cm−1
257,500
308,700
180,200
131,500
152,100
136,800
)
PR-PPY
0.2575
0.3087
0.1802
0.1315
0.1521
0.1368
FN-PPY
RuP(PR-PPY)
RuP(FN-PPY)
RuB(PR-PPY)
RuB(FN-PPY)

J Fluoresc
Fig. 7 Fluorescence spectra of
pyrene-appended polypyridine
ligand PR-PPY and
Ruthenium(II) complexes in
acetonitrile medium at room
temperature with the
concentration of 1 × 10−6
M
bands of the complexes RuB(PR-PPY) and RuB(FN-PPY)
with bpy as ancillary ligands (λmax =475 and 453 nm, respec-
tively) and that of the complexes RuP(PR-PPY) and RuP(FN-
PPY) with phen as ancillary ligands (λmax = 485 and 476 nm,
respectively) are bathochromically shifted with respect to that
of [Ru(bpy)3]2+ (λmax = 451 nm) and [Ru(phen)3]2+
(λmax = 446 nm) which can be attributed to the extension
of the π-framework in the ligands. The MLCT absorption
maxima of the four complexes are redshifted compared with
that of Ru(bpy)32+ and Ru(phen)32+ [25] because pyrene and
phenanthroline-appended polypyridine ligands have larger π-
frameworks.
The emission maxima of the pyrene-appended
polypyridine ligand PR-PPY is observed at λems = 616 nm
and the phenanthroline-appended polypyridine ligand FN-
PPYis observed at λems = 668 nm. And the emission maxima
of the mononuclear complexes RuP(PR-PPY) and RuB(PR-
PPY) are observed at λems = 646 nm. The emission maxima
of the dinuclear complexes RuP(FN-PPY) and RuB(FN-PPY)
are observed at λems = 685 nm.
When look at their fluorescence spectra, it can be ob-
served that the fluorescence intensities of the ligands are
higher than their metal complexes (Figs. 7 and 8). This is
because of quenching effect of Ruthenium(II) metal on
chromophore groups. The emission of Ruthenium(II) spe-
cies is assigned to the MLCT state involving the bridging
ligand as the acceptor site and the emitting MLCT state of
the acceptor ligand does not extend over to the core of the
bridging ligand, but it only involves the phenyl group di-
rectly connected to the imidazo[4,5-f][1,10]phenanthroline
moiety.
Fluorescence Spectra
The fluorescence spectra of the polypyridine ligands and com-
plexes have been recorded in acetonitrile solution at a working
concentration of 1 × 10−6 mol/L with excitation wavelenght
275 nm in the range 200 and 800 nm.
Fig. 8 Fluorescence spectra of
phenanthroline-appended
polypyridine ligand FN-PPY and
Ruthenium(II) complexes in
acetonitrile medium at room
temperature with the
concentration of 1 × 10−6
M

J Fluoresc
3. Kursunlu AN (2015) Tetrahedron Lett 56:1873–1877
4. Devi CS, Satyanarayana S (2012) J Coord Chem 65(3):474–486
5. Kursunlu AN (2014) RSC Adv 4(88):47690–47696
6. Xiong Y, Ji L-N (1999) Coord Chem Rev 185–186:711–733
7. Balzani V, Juris A (2001) Coord Chem Rev 211:97–115
8. Cheng F, Tang N, Chen J, Wang F, Chen L (2010) Inorg Chem
Commun 13:757–761
9. Chao H, Qiu Z-R, Cai L-R, Zhang H, Li X-Y, K.-S.Wong, Ji L-N
(2003) Inorg Chem 42(26):8600–8910
10. Cheng F, Tang N, Chen J, Chen L, Jia L, Chen G (2010) Inorg
Chem Commun 13:258–261
11. Yilmaz Obali A, Ucan HI (2012) J Fluoresc 22:1357–1370
12. Zhenga Z-B, Duana Z-M, Zhanga J-X, Wang K-Z (2012) Sensors
Actuators B 169:312–319
13. Ziessel R (2001) Coord Chem Rev 216–217:195–223
14. Wang X-L, Chen Y-Q, Liu G-C, Zhang J-X, Lin H-Y, Chen B-K
(2010) Inorg Chim Acta 363:773–778
15. Lodeiro C, Limaa JC, Parola AJ, Seixas de Melo JS, Capelo JL,
Covelo B, Tamayoa A, Pedras B (2006) Sensors Actuators B 115:
276–286
16. Kursunlu AN, Güler E (2013) Supramol Chem 25(8):512–521
17. Fleischel O, Wu N, Petitjean A (2010) Chem Commun 46:8454–
8456
Conclusion
In this context, novel different substitued polypyridine ligands
are presented. Pyrene-appended polypyridine ligand PR-PPY
and phenanthroline-appended polypyridine ligand FN-PPY
are synthesized by means of Schiff base condesation reaction.
BA-PPY has been reacted with 1-pyrene(methylamine) hy-
drochloride for PR-PPY formation and 1,10-phenanthroline-
5amine for FN-PPY formation. BA-PPY is also a novel
polypyridine ligand. These highly fluorescent Schiff base
polypyridine ligands have remarkable photophysical behav-
iours. And also, all ligands contain a potential N,N-donor
group capable of coordinating with the Ruthenium(II) metal.
The BA-DIPPY polypyridine ligand has been synthesized by
part of ‘Click Chemistry’. As mentioned in experimental part
the synthesis steps contain different substitued novel BR-PPY
and N3-PPY polypyridine ligands, respectively. The charac-
terization were performed by UV-Vis Spectroscopy,
1
Fluorescence Spectroscopy, FT-IR Spectroscopy, H-NMR
Spectroscopy, Elemental Analysis, TG/DTA Analysis,
Magnetic Susceptibility.
18. Zheng RH, Guo HC, Jiang HJ, Xu KH, Liu BB, Sun WL, Shen ZQ
(2010) Chin Chem Lett 21:1270–1272
19. Lenaerts P, Storms A, Mullens J, D’Haen J, Görller-Walrand C,
Binnemans K, Driesen K (2005) Chem Mater 17:5194–5201
20. Ji Z, Huang SD, Guadalupe AR (2000) Inorg Chim Acta 305:127–
134
Acknowledgments We thank the Scientific Research Projects
Foundation of Selcuk University (SUBAP) (Konya/TURKEY) for finan-
cial support of this work produced from a part of Aslıhan YILMAZ
OBALI’s PhD Thesis.
21. Sullivan BP, Salmon DJ, Meyer TJ (1978) Inorg Chem 17(12):
3334–3341
22. Jing L, Dingmei Z, Xun Z, Zhenjian H, Shu L, Mengfeng L, Jiyan
P, Yongcheng L (2011) Mar. Drugs 9:1887–1901
23. Rose MJ, Patra AK, Alcid EA, Olmstead MM, Mascharak PK
(2007) Inorg Chem 46(6):2328–2338
References
24. Kumar P, Sain B, Jain SL (2014) J Mater Chem A 2:11246–11253
25. Rillema DP, Mack KB (1982) Inorg Chem 21:3849–3854
1. Yilmaz Obali A, Ucan HI (2015) J Fluoresc 25:647–655
2. Kursunlu AN (2015) RSC Adv 5(51):41025–41032