Role of p(Z)-π(Ar/Nap) conjugation in structures of 1-(arylchalcogena) naphthalenes for Z = Te versus Se, S and O: Experimental and theoretical investigations

View Article Online / Journal Homepage / Table of Contents for this issue

Dynamic Article Links

Dalton

Transactions

Cite this: Dalton Trans., 2012, 41, 7485

www.rsc.org/dalton

PAPER

Role of p(Z)–π(Ar/Nap) conjugation in structures of 1-(arylchalcogena)-

naphthalenes for Z = Te versus Se, S and O: experimental and theoretical

investigations†

Takahito Nakai, Mitsuhiro Nishino, Satoko Hayashi, Masato Hashimoto and Waro Nakanishi*

Received 3rd March 2012, Accepted 13th April 2012

DOI: 10.1039/c2dt30516j

Magnitudes of the p(Z)–π(Ar/Nap) conjugation were evaluated for 1-(arylchalcogena)naphthalenes

(1-(ArZ)Nap, 1-(p-YC₆H₄Z)C₁₀H₇; 1 (Z = Te), 2 (Se), 3 (S) and 4 (O)). Structures of 1 were determined

by X-ray analysis for Y = NMe₂(b), OMe (c) and CN (i). For 1b and 1c that have electron donating Y,

the Z–C_Arbond is located on the naphthyl plane with Z–C_Napbeing perpendicular to the aryl plane,

which we deﬁne as (B: pd). On the other hand, the structure of 1i with electron donating Y is (A: pl), of

which Z–C_Aris placed almost perpendicular to the naphthyl plane with Z–C_Napbeing located on the aryl

plane. Each structure of 1a (Y = H), 1b, 1c, 1d (Me), 1e (F), 1f (Cl), 1g (Br), 1h (COOEt), 1i and 1j

(NO₂) was determined by NMR in chloroform-d. Structures of 1 in the solutions are (B: pd) for b, c and

e that have electron donating Y, (A: pl) for f–j with electron accepting Y, and in equilibrium between

(B: pd) and (A: pl) for a and d of which Y are rather neutral. The results for 2–4 are very similar to those

of 1 in solutions. Quantum chemical calculations were performed on 1–4 with Y of a, b′ (NH₂), d, f and

j. Magnitudes of the p(Z)–π(Ar/Nap) conjugation were well-evaluated by NBO (natural bond orbital)

analysis. The values were 12.6 and 13.0 kcal mol⁻¹for the typical forms of (A: pl) and (B: pd) of 1a,

respectively, resulting in a much smaller energy difference between the two (0.4 kcal mol⁻¹), which

should correspond to the observed result. It is well-demonstrated that the p(Te)–π(Ar/Nap) conjugation

operates effectively in 1, although the magnitudes increase in the order of Z = Te < Se < S < O. Thermal

effect of the Gibbs free energies is shown to play an important role in the energy proﬁles of 1a–4a.

The p(Se)–π(Ar/Nap) conjugation is well-demonstrated to

operate as the factor to determine the ﬁne structures of 2. The

Introduction

Much attention has been paid to the p–π conjugation of the

p(Z)–π(CvC) and p(Z)–π(Ar) types not only for Z of second

low elements, but also that of heavier ones.^1–5The conjugation

will control ﬁne structures⁶and reactivities of compounds,

together with delicate properties of materials, such as electronic

absorption–emission energies and NMR chemical shifts. It is of

current interest to clarify the factors that control the structures of

1-(arylchalcogena)naphthalenes, especially for the tellurium

derivative, as well as selenium,^2–5,7–18sulfur¹⁹and oxygen¹⁹

derivatives [1-(ArZ)Nap, 1-(p-YC₆H₄Z)C₁₀H₇: 1 (Z = Te),

2 (Z = Se), 3 (Z = S) and 4 (Z = O); Y = H (a), NMe₂(b), OMe

(c), d (Me), e (F), f (Cl), g (Br), h (COOEt), i (CN) and

j (NO₂)]. Chart 1 shows 1-(arylchalcogena)naphthalenes, 1–4.

role of p(Te)–π(Ar/Nap) conjugation in 1 should be established

in the same accuracy with the uniﬁed form to 2, together with 3

and 4. Scheme 1 illustrates the p(Z)–π(Ar/Nap) conjugation in

1–4. However, the role of the p(Te)–π(Ar/Nap) conjugation is

unclear yet, including whether it operates well in determining

the ﬁne structures of 1, relative to the case of 2. It may be the

natural consequence of the present situation, since the structures

of 1 that were determined by the X-ray crystallographic analysis

are seldom found in the literature, to the best of our knowledge.

Quantum chemical (QC) calculations have also rarely been

Department of Material Science and Chemistry, Faculty of Systems

Engineering, Wakayama University, 930 Sakaedani, Wakayama

640-8510, Japan. E-mail: nakanisi@sys.wakayama-u.ac.jp;

Fax: +81 73 457 8253; Tel: +81 73 457 8252

†Electronic supplementary information (ESI) available: Cartesian coor-

dinates for optimized structures of 1a–4a, 1b′–4b′, 1d–4d, 1f–4f and

1j–4j. CCDC 838257 for 1b, 838258 for 1c and 838259 for 1i. For ESI

and crystallographic data in CIF or other electronic format see DOI:

10.1039/c2dt30516j

Chart 1 1-(Arylchalcogena)naphthalenes 1–4.

Dalton Trans., 2012, 41, 7485–7497 | 7485

This journal is © The Royal Society of Chemistry 2012

View Article Online

Scheme 1 Factors to stabilize (A: pl) and (B: pd) conformations.

Scheme 2 Types A–C in a naphthalene system and pd, pl and np in a

benzene system.

Fig. 1 An ORTEP drawing of 1b with atomic numbering scheme for

selected atoms (50% probability thermal level).

Chart 2 Structures of 9-(arylselanyl)anthracenes (5) and 1-(arylsela-

nyl)anthraquinones (6).

plane (B) with Z–C_Napbeing perpendicular to the aryl plane

(pd). The C structure and the np conformer are intermediate

between A and B and between pd and pl, respectively. The A, B

and C structures with the pl, pd and np conformers are closely

related to the p(Z)–π(Ar/Nap) conjugation in 1–4.

Structures in the solid state are sometimes deformed by the

crystal packing effect, so are the solvent effect in solutions.

Therefore, QC calculations of a satisfactory level are crucial to

establish the role of the p(Te)–π(Ar/Nap) conjugation. QC calcu-

lations were performed on 1–4 with Y = H (a), NH₂(b′),

Me (d), Cl (f) and NO₂( j) at the Møller–Plesset second-order

energy correlation (MP2)²³level using the Gaussian 03

program.²⁴The thermal effect of the Gibbs free energies was

evaluated for 1a–4a through frequency analysis.

Both structures determined experimentally and predicted

theoretically were examined and compared carefully. The role of

the p(Te)–π(Ar/Nap) conjugation in the ﬁne structures of 1 was

thus clariﬁed. The results are discussed in relation to the role of

such conjugation in 1–4 to draw a conclusion in the uniﬁed form

for 1–4. QC calculations performed on 1–4 played a very impor-

tant role for the conclusion, as well as the structural

determination.

performed to clarify the role of the conjugation in the ﬁne struc-

tures of 1.

It is also of current interest for the derivatives of 1–4 to react

with metals or halogens yielding complexes with interesting

structures and properties.²⁰The p–π conjugation must serve as

one of the basic concepts in chalcogen chemistry. The

p(Z)–π(CvC/Ar) conjugation may be believed to decrease

swiftly as Z becomes heavier. Therefore, it is necessary to estab-

lish a ﬁrm basis for the p(Te)–π(CvC/Ar) conjugation. To

accomplish this purpose, it is inevitable to determine the struc-

tures of 1. However, there must be some impediment, such as

the oily nature or unsuitable crystallization of 1, during the

X-ray crystallographic analysis for all members in Chart 1.

In such cases, structural determination in solutions becomes

very important. Chart 2 illustrates 9-(arylselanyl)anthracenes

(5a–5j) and 1-(arylselanyl)anthraquinones (6a–6j), the struc-

tures of which have been demonstrated to be all (A: pl) and

(B: pd), respectively, in solutions.²¹Structures of 1a–1j have

been determined in solutions employing NMR chemical shifts of

5a–5j and 6a–6j as references, similarly to the case of 2.¹²It

would be very useful if the structures of 1–4 could be deter-

mined in solutions, since structural determination using NMR

must be easier. We are faced with such cases on a daily basis,

where the structures are determined in solutions to understand or

explain the properties and reactivity of compounds.

Results and discussion

Structures of 1-(ArTe)Nap (1) in crystals

Type A (abbreviated by A), B and C notation^11,12,15is

employed here, which has been proposed for the naphthalene

system with the planar (pl), perpendicular (pd) and the non-

planar non-perpendicular (np) notation for the aryl group.^15,16,22

Scheme 2 shows the A, B and C notation exempliﬁed by 8-G-1-

XZC₁₀H₆and the pl, pd and np conformers in C₆H₅ZX. The

combined notation will be practically used for the structures

of 1–4: a structure of 1-(ArZ)Nap is called (A: pl) when the

Z–C_Arbond is almost perpendicular to the naphthyl plane (A),

with Z–C_Napbeing located on the aryl plane (pl), whereas it is

(B: pd) if the Z–C_Arbond is almost placed on the naphthyl

1-(Aryltellanyl)naphthalenes of 1b, 1c and 1i were newly pre-

pared according to the method reported earlier for 1a, 1d–h and

1j,¹⁹which are also employed in this work.

Single crystals of 1b, 1c and 1i were obtained via slow evap-

oration of n-hexane solutions and one suitable crystal was sub-

jected to X-ray crystallographic analysis for each. Only one type

of structure was found for each of them in the crystal. Fig. 1–3

show the structures of 1b, 1c and 1i, respectively. Table 1 col-

lects the selected interatomic distances, angles and torsional

angles of 1b, 1c and 1i.

7486 | Dalton Trans., 2012, 41, 7485–7497

This journal is © The Royal Society of Chemistry 2012

View Article Online

Table 1 Selected interatomic distances, angles and torsional angles of

1b, 1c and 1i

Compound

Y =

1b

NMe₂

1c

OMe

1i

CN

Bond distances (Å)

TeC₁

TeC₁₁

2.120(2)

2.100(2)

2.124(2)

2.106(2)

2.1234(17)

2.1120(17)

Fig. 2 An ORTEP drawing of 1c with atomic numbering scheme for

selected atoms (50% probability thermal level).

Angles (°)

C₁TeC₁₁

99.93(8)

97.97(8)

96.32(6)

TeC₁C₂

TeC₁C₁₀

TeC₁₁C₁₂

TeC₁₁C₁₆

121.42(15)

118.62(15)

119.93(15)

121.25(15)

121.54(15)

118.28(14)

120.07(16)

120.60(15)

117.98(13)

121.61(12)

117.87(13)

122.50(12)

Torsional angles (°)

C₁TeC₁₁C₁₂

C₁TeC₁₁C₁₆

C₁₁TeC₁C₂

C₁₁TeC₁C₁₀

TeC₁C₂C₃

TeC₁C₁₀C₅

106.37(2)

−84.03(2)

0.26(2)

179.70(2)

−179.10(2)

179.85(2)

80.27(2)

171.65(2)

−10.95(2)

83.32(2)

94.52(2)

−177.03(2)

176.37(2)

−106.19(2)

−3.76(2)

178.50(2)

−176.74(2)

175.21(2)

Fig. 3 An ORTEP drawing of 1i with atomic numbering scheme for

selected atoms (50% probability thermal level).

Intermolecular interactions of 1b, 1c and 1i in the solid state

are given in Fig. S1–S3 of the ESI.† Intermolecular interactions

are observed between C₆H₄NMe₂in the crystal of 1b (B: pd),

while they occur between TeC₆H₄OMe in 1c (B: pd), although

one of the H atoms in the naphthyl group participates in the

interactions. On the other hand, intermolecular interactions are

observed between the naphthyl group and the Te atom in

1i (A: pl). Indeed, each structure could be affected by the crystal

packing effect, but the effect is expected not to control the struc-

tures of 1b, 1c and 1i. The intermolecular interactions would be

the result of their speciﬁc structures with the nature of Te and Y.

The structures of 1b and 1c are (B: pd), which are essentially

the same as those of 2c,¹⁵3c¹⁹and 4c,¹⁹whereas that of 1i is

(A: pl), which is very close to those of 2f,¹⁵2g,¹⁵2h,¹⁵3g,¹⁹

4a¹⁹and 4j.¹⁹The planarity of the naphthyl, p-N,N-dimethyl-

aminophenyl, p-anisyl and p-cyanophenyl planes in 1b, 1c and

1i are very good, as shown in Fig. 1–3. The p-N,N-dimethylami-

nophenyl plane in 1b and the p-anisyl plane in 1c are perpen-

dicular to the naphthyl plane, with the Te–C_Arbonds being

placed on the naphthyl plane and the Te–C_Napbonds perpendicu-

lar to the aryl plane. In the structures of 1b and 1c, torsional

angles C₁₁TeC₁C₁₀were 179.70(2)° and 178.50(2)°, torsional

angles C₁TeC₁₁C₁₂were 106.37(2)° and 80.27(2)°, and angles

Fig. 4 Structures of 1–4 in crystals containing various Y.

Survey of the structures of 1-(ArZ)Nap (1–4) in crystals

Fig. 4 collects together the structures of 1–4 determined in crys-

tals in this work and those reported so far, which are 1b, 1c, 1i,

2c, 2f, 2g, 2h, 3c, 3g, 4a, 4c and 4j.

While electrons in the p-type lone pair orbital of Z (p(Z)) are

stabilized through the p(Z)–π(C₆H₄Y) conjugation when the

structure is (A: pl), the p(Z)–π(Nap) conjugation contributes for

(B: pd), as illustrated in Scheme 1. The main factor that controls

the relative stability between (A: pl) and (B: pd) depends on the

relative contributions between the p(Z)–π(C₆H₄Y) and

p(Z)–π(Nap) conjugations. The p(Z)–π(C₆H₄Y) conjugation

should be more effective than the p(Z)–π(Nap) conjugation in

(A: pl) and vice versa, as observed.

C

_NapTeC_Arwere 99.93(8)° and 97.97(8)°, respectively. On the

other hand, the p-cyanophenyl plane in 1i was perpendicular to

the naphthyl plane, with the Te–C_Arbond being perpendicular to

the naphthyl plane and the Te–C_Napbond placed on the aryl

plane. The torsional angles of C₁₁TeC₁C₂and C₁TeC₁₁C₁₂were

83.32(2)° and 171.65(2)°, respectively. The angle of C₁TeC₁₁

was 96.32(6)°. The data conﬁrm the (B: pd) structures for 1b

and 1c and the (A: pl) structure of 1i.

This journal is © The Royal Society of Chemistry 2012

Dalton Trans., 2012, 41, 7485–7497 | 7487

View Article Online

Table 2 Substituent-induced chemical shifts (δ_SCS

)

of ¹H, ¹³C,

the n-position and C_ifor the ipso-carbon as shown in Chart 1.

Table 2 also contains δ(H_n)_SCS, δ(C_i)_SCSand δ(Se)_SCSfor 2, 5

and 6 (see Charts 1 and 2).²¹NMR chemical shifts measured

from TMS for the parent compounds (Y = H: 1a, 2a, 5a and 6a)

are given in parenthesis. Those of 3 and 4 are given in Table S1

of the ESI.†

Fine structures of 1a–1j in chloroform-d solutions were deter-

mined employing NMR chemical shifts of 5a–5j and 6a–6j as

references, via those of 2a–2j.^13,21The strategy to determine the

structures of 1–4 in solutions was as follows: structures of 1–4

should be (A: pl) in solutions for those with arbitrary substitu-

ents, Y_s, Y_tand Y_u, if plots of δ_SCSin 1–4 versus δ_SCSin 5 give

a very good correlation for those with Y_s, Y_tand Y_u, since the

structures of 5 are (A: pl) for all Y in solutions. Similarly, those

with Y_s, Y_tand Y_ushould be (B: pd) in solutions if a very good

correlation is obtained for those with Y_s, Y_tand Y_uin the plot of

δ_SCSin 1–4 versus δ_SCSin 6, since the structures of 6 are all

(B: pd) in solutions.

¹²⁵Te and/or ⁷⁷Se of 1 and 2, together with 5 and 6

Chemical Shift

Compound

1

δ(H₂)_SCS

δ(H₈)_SCS

δ(C_i)_SCS

δ(Te)_SCS

Y = H (a)

0.000

0.00

(570.7)^a

−32.4

−14.6

−10.4

1.4

3.6

3.9

7.4

25.4

25.5

(7.972)^a

−0.381

−0.237

−0.117

−0.092

0.010

(8.135)^a

−0.180

−0.119

−0.052

−0.060

−0.025

−0.029

0.018

(114.7)^a

−18.2

−11.8

−4.5

−6.6

−2.2

−1.0

8.1

NMe₂(b)

OMe (c)

Me (d)

F (e)

Cl (f)

Br (g)

0.021

0.174

0.236

CO₂Et (h)

CN (i)

0.027

9.8

NO₂(j)

0.270

0.033

12.0

2

δ(H₂)_SCS

δ(H₈)_SCS

δ(C_i)_SCS

δ(Se)_SCS

Y = H (a)

0.000

0.00

0.0

(7.776)^a

−0.467

−0.277

−0.108

−0.101

0.003

(8.348)^a

−0.088

−0.068

−0.021

−0.053

−0.062

−0.059

−0.068

−0.101

−0.109

(131.66)^a

−18.15

−11.48

−4.37

−5.98

−1.55

−0.64

8.17

(361.0)^a

−17.2

−6.8

−4.8

−5.0

−1.6

−1.7

7.0

NMe₂(b)

OMe (c)

Me (d)

F (e)

Cl (f)

Br (g)

CO₂Et (h)

CN (i)

NO₂(j)

Conﬁrmation of the structures for 2a–2j in solutions

It seems complex to discuss the structures of 1–4 in solutions in

the uniﬁed form, at ﬁrst glance. Therefore, compounds contain-

ing the most similarities are examined ﬁrst: 2, 5 and 6 are the

nice candidates to be discussed ﬁrst, since they are all organic

selenium compounds. Structures of 1–4 in solutions were deter-

mined as follows. (1) Fine structures⁶of 2a–2j were established

in solutions ﬁrst, employing the NMR data of 5a–5j and 6a–6j

as references. (2) Fine structures of 1a–1j in solutions were

conﬁrmed next, employing the NMR data of 2a–2j as references.

(3) Then, ﬁne structures of 3 and 4 in solutions are discussed

similarly.

The δ(C_i)_SCSvalues of 2 (δ(C_i: 2)_SCS) were plotted versus

δ(C_i: 5)_SCSand δ(C_i: 6)_SCS. Fig. 5a and b show the plots,

respectively. The plots are analyzed for Y separately by three

groups: Y = H (a) and Me (d) make a group (G(l)), Y = NMe₂

(b), OMe (c) and F (e) make the second group (G(m)) and

Y = Cl (f), Br (g), COOEt (h), CN (i) and NO₂( j) belong to

the third one (G(n)). The correlations are excellent and are given

in the entries 1–4 in Table 3. The (a, R²) values in Fig. 5a are

(1.300, 0.9998) for G(m) and (0.932, 0.9997) for G(n), whereas

the values in Fig. 5b are (1.167, 0.9999) for G(m) and (3.527,

0.973) for G(n).

0.021

0.096

0.113

0.125

9.45

12.36

13.8

18.6

5

δ(H₁)_SCSδ(H_{10 SCS}

)

δ(H_o)_SCSδ(C_i)_SCS

δ(Se)_SCS

Y = H (a)

0.000

0.00

0.0

(8.884)^a

0.127

(8.567)^a

−0.077

−0.045

−0.019

−0.008

0.008

(7.057)^a

0.084

(126.57)^a(249.0)^a

NMe₂(b)

OMe (c)

Me (d)

F (e)

Cl (f)

Br (g)

CO₂Et (h) −0.166

CN (i)

NO₂(j)

−8.13

−3.11

−1.13

1.24

2.83

3.94

13.23

14.89

17.73

−21.0

−12.2

−6.6

−3.6

1.5

0.045

0.005

−0.028

−0.075

−0.084

0.044

−0.068

0.005

−0.073

−0.157

−0.017

−0.028

−0.007

0.010

0.071

0.060

0.103

1.6

16.2

26.2

30.3

−0.186

−0.218

6

δ(H₂)_SCSδ(H₈)_SCSδ(H_o)_SCSδ(C_i)_SCS

δ(Se)_SCS

Y = H (a)

0.000

(8.352)^a

0.024

0.022

0.013

0.005

0.011

0.010

0.016

0.011

0.018

0.00

0.0

(7.237)^a

0.102

(7.724)^a

−0.196

−0.102

−0.128

−0.032

−0.071

−0.144

0.046

(127.44)^a(512.3)^a

NMe₂(b)

OMe (c)

Me (d)

F (e)

Cl (f)

Br (g)

CO₂Et (h) −0.052

CN (i)

NO₂(j)

−13.87

−8.05

−2.06

−3.45

2.21

5.26

−19.5

−15.0

−8.9

−10.1

−7.0

−6.4

0.0

0.023

0.024

−0.038

−0.017

−0.012

The (a, R²) values change depending on whether the mechan-

isms are similar or different.^21aFor the plots of δ(C_i: 2)_SCS

versus δ(C_i: 5)_SCSin Fig. 5a, the a value for G(n) (0.932) is sub-

stantially closer to 1.0, relative to that for G(m) (1.300), whereas

that for G(m) (1.167) is much closer to 1.0, relative to G(n)

(3.527), in the plot of δ(C_i: 2)_SCSversus δ(C_i: 6)_SCS(Fig. 5b).

Data for G(l) somewhat deviate from the correlations both in

Fig. 5a and b. The results are well-explained by assuming that

the structures of 2 are (A: pl) for G(n), (B: pd) for G(m) and in

equilibrium between (A: pl) and (B: pd) for G(l).

−0.056

−0.052

−0.009

0.196

5.27

5.66

8.2

2.5

^aδ(H)_SCS, δ(C)_SCS, δ(Te)_SCSand/or δ(Se)_SCSare given for 1, 2, 5 and 6,

together with δ(H), δ(C), δ(Te) and/or δ(Se) for 1a, 2a, 5a and 6a in

parenthesis, measured in chloroform-d (0.050 mol L⁻¹) at 24 °C.

The δ(H₂: 2)_SCSvalues should correspond to δ(H₁: 5)_SCSfor

G(n) and δ(H₂: 2)_SCSwould do to δ(H₂: 6) for G(m).

δ(H₂: 2)_SCSare plotted versus δ(H₁: 5) and δ(H₂: 6)_SCS, which

are drawn in Fig. S4 in the ESI.† Correlations for G(n) and

G(m) of the plots are given in entries 5–8 in Table 3. The results

for δ(H₂: 2)_SCSsupport the above conclusion that the structures

Structures of 1-(ArTe)Nap (1) in solutions

NMR chemical shifts were measured at 400 MHz for 1a–1j in

chloroform-d (0.050 mol L⁻¹) at 24 °C.²⁵Table 2 summarizes

the selected substituent induced chemical shifts (SCS) of

δ(H_n)_SCS, δ(C_i)_SCSand δ(Te)_SCSfor 1, where H_nstand for H at

7488 | Dalton Trans., 2012, 41, 7485–7497

This journal is © The Royal Society of Chemistry 2012

View Article Online

of 2 are (A: pl) for G(n) and (B: pd) for G(m), with equilibrium

between (A: pl) and (B: pd) for G(l).

The δ(Se)_SCSvalues must also be a good measure to deter-

mine the ﬁne structures of 2 in solutions. Fig. S5a and b in the

ESI† show the plots of δ(Se: 2)_SCSversus δ(Se: 5)_SCSand

δ(Se: 6)_SCS, respectively. The correlation for G(n) in the plot of

δ(Se: 2)_SCSversus δ(Se: 5)_SCSis given in entry 9 in Table 3. The

good correlation for G(n) supports the above conclusion of

(A: pl) for G(n: 2). Data of 2e in G(m) deviate from the corre-

lation line of 2b and 2c in the plot of δ(Se: 2)_SCSversus

δ(Se: 5)_SCS(see entry 10 in Table 3), which may show some

equilibrium between (B: pd) and (A: pl) for 2e. Correlations in

the plot of δ(Se: 2)_SCSversus δ(Se: 6)_SCSare given in entries 11

and 12 in Table 3. The behavior of δ(Se: 2)_SCSessentially

support the (A: pl) structure for G(n) and (B: pd) for G(m) with

equilibrium between (A: pl) and (B: pd) for G(l) in 2.

After conﬁrmation of the structure of 2 in solutions separately

by Y, the next extension is to determine the structures of 1, 3 and

4 in solutions, based on NMR parameters.

Structural determination of 1, 3 and 4 in solutions

What are the similarities and differences in the structures of 1–4?

δ(C_i)_SCSare discussed ﬁrst. Fig. 6 shows the plots of δ(C_i: 1, 3

and 4)_SCSversus δ(C_i: 2)_SCS. They gave excellent correlations

with no deviations, which are given in entries 13–15 in Table 3.

The results support that the structures of 1–4 are essentially

(B: pd) for G(m), (A: pl) for G(n) and in the equilibrium

between the two for G(l). Slopes for the correlations in 1 and 3

are very close to 1.0, but that of 4 is much smaller, which

suggests that the structural features in 1–3 are more similar to

each other, compared to the case of 4.

Fig. 5 Plots of δ(C_i: 2)_SCSversus δ(C_i: 5)_SCS(a) and δ(C_i: 2)_SCS

versus δ(C_i: 6)_SCS(b). Plots are analyzed by three groups, G(l), G(m)

and G(n), and drawn as black circle, red triangle and blue rectangle,

respectively.

To understand the structure of 1 in solutions in more detail,

δ(H₂: 1)_SCSwere plotted versus δ(H₂: 2)_SCS. Fig. S6 in the ESI†

Table 3 Correlations in the plots of δ(H)_SCS, δ(C)_SCS, δ(Se)_SCSand/or δ(Te)_SCSfor 1–6 analyzed separately mainly by three groups^a

Entries

Y

x

a

b

R²

G(x)

Structure

1

2

3

4

5

6

7

8

δ(C_i: 2)_SCS

δ(H₂: 2)_SCS

δ(Se: 2)_SCS

δ(C_i: 1)_SCS

δ(C_i: 3)_SCS

δ(C_i: 4)_SCS

δ(H₂: 1)_SCS

δ(H₂: 3)_SCS

δ(H₂: 4)_SCS

δ(Te: 1)_SCS

δ(C_i: 5)_SCS

δ(C_i: 6)_SCS

δ(H₁: 5)_SCS

δ(H₂: 6)_SCS

δ(Se: 5)_SCS

δ(Se: 6)_SCS

δ(C_i: 2)_SCS

δ(H₂: 2)_SCS

δ(Se: 2)_SCS

1.300

0.932

1.167

3.527

−1.862

−1.897

−2.053

−5.374

0.673

1.182

1.050

2.311

1.007

0.972

0.572

0.789

2.147

1.044

2.156

0.227

1.467

1.812

−7.54

−4.25

−2.00

−8.98

−0.15

−0.13

−0.17

−0.06

−2.98

7.62

0.9998

0.9997

0.9999

0.973

0.9999

0.992

0.994

0.908

0.990

G(m)

G(n)

G(m)

G(n)

G(m)

G(n)

G(m)

G(n)

(B: pd)

(A: pl)

(B: pd)

(A: pl)

(B: pd)

(A: pl)

(B: pd)

(A: pl)

(B: pd)

(A: pl)

(B: pd)

9

G(n)

10

11

12

13

14

15

16

17

18

19

20

21

22

G(m*)^b

G(n)

5.74

0.986

27.87

−0.21

−0.09

−0.48

−0.01

0.00

0.01

0.00

−0.01

−1.68

G(m*)^b

All

0.990

0.998

0.992

0.999

0.983

0.999

0.989

0.999

0.982

0.990

All

G(m)

G(n)

(B: pd)

(A: pl)

(B: pd)

(A: pl)

(B: pd)

(A: pl)

G(m′)^c

G(n′)^d

G(m′)^c

G(n′)^d

^aG(l) with Y = H (a) and Me (d); G(m) with Y = NMe₂(b), OMe (c) and F (e); G(n) of Y = Cl (f), Br (g), COOEt (h), CN (i) and NO₂(j). ^bG(m*)

of Y = NMe₂(b) and OMe (c). ^cG(m′) with Y = H (a), OMe (c) and Me (d). ^dG(n′) with Y = Cl (f), Br (g), COOEt (h) and NO₂(j).

This journal is © The Royal Society of Chemistry 2012

Dalton Trans., 2012, 41, 7485–7497 | 7489

View Article Online

shows the plot. The plot was analyzed by three groups; G(m)

and G(n) with the equilibrium nature for G(l). The correlations

are given in entries 16 and 17 in Table 3. Different correlations

are recorded for G(m) and G(n) in this case. This must be the

reﬂection of the different anisotropic effect at H₂from

SeC₆H₄Y-p and TeC₆H₄Y-p in (B: pd) and (A: pl), together with

the bond lengths. The results are also consistent with the con-

clusion of the (A: pl) structure for G(n) and (B: pd) for G(m)

with the equilibrium for G(l) in 1 and 2.

(see Fig. S7 in the ESI†). The plots should be analyzed by three

groups of G(l), G(m) and G(n). However, the plots were ana-

lyzed as two correlations with G(m′) of Y = H (a), OMe (d) and

Me (a) and G(n′) of Y = Cl (f), Br (g), COOEt (h) and NO₂( j)

due to a lack of data for NMe₂, F and CN. The correlations are

given in entries 18–21 in Table 3. The relations in the structures

of 3 and 4 versus 2 are similar to the case of 1 versus 2.

δ(Te: 1)_SCSare plotted versus δ(Se: 2)_SCS. Fig. 7 shows the

results. The correlation was also good, as shown in entry 22,

although data for Y = F, Cl, Br and NO₂are omitted from the

correlation line. Firm standards for δ(Te)_SCSseem necessary for

The structures of 3 and 4 were similarly examined as dis-

cussed in 1. δ(H₂: 3 and 4)_SCSwere plotted versus δ(H₂: 2)_SCS

the ﬁnal conclusion based on δ(Te)_SCS.

²⁶The Te derivatives of 5

and 6 would be the candidates for the standards. Table 4 sum-

marizes the structures of 1–4 determined in the solutions using

NMR.

After determination of the ﬁne structures of 1–4, in crystals

and solutions, the next extension is to clarify the energy proﬁles

of 1–4 on the basis of the theoretical background.

QC calculations on 1-(ArZ)Nap (1–4)

Structures and energies evaluated on the basis of QC calculations

correspond to those in the gas phase, so do the nature of inter-

actions. We must be careful when structures, energies and

proﬁles are discussed on the basis of QC calculations, since

other factors, such as the crystal packing effect in crystals and

the solvent effect in solutions, would be stronger than those pre-

dicted by QC calculations. However, factors to stabilize the

structures in the gas phase must also operate in solid states and

solutions, which enable us to clarify the nature of interactions by

the careful comparison of the calculated results with the

observed ones.

Fig. 6 Plots of δ(C_i)_SCSof 1, 3 and 4 versus δ(C_i: 2)_SCS. G(l), G(m)

and G(n) are drawn in black, red and blue, respectively.

Z-dependence in structures of 1-(PhZ)Nap (1a–4a)

The pl, pd and np conformations of the aryl group will change

depending on the A, B and C structures for the naphthyl group

in 1a–4a. Therefore, the discussion on the basis of the theoretical

calculations of 1a–4a is focused on the A, B and C structures

for the naphthyl group, ﬁrst. Tables 5 and 6 collect the optimized

structures for 1a and 2a, respectively, conﬁrmed by the fre-

quency analysis. Those for 3a and 4a are collected in Tables S2

and S3 in the ESI,† respectively. Energies on the potential

energy surface are given by E and the energy differences on the

potential energy surface from a standard are by ΔE. Those with

thermal correction to Gibbs free energy are denoted by E_GFand

ΔE_GF, respectively. While A is the global minimum, B′ is the

local minimum for each of 1a–4a on the energy surface. The B′

Fig. 7 A plot of δ(Te: 1)_SCSversus δ(Se: 2)_SCS

Table 4 Structures of 1–4 in solutions^a

.

NMe₂

(b)

OMe

(c)

Me

(d)

H

(a)

F

(e)

Cl/Br

(f/g)

CO₂Et

(h)

CN

(i)

NO₂

(j)

Z/Y

Te (1)

Se (2)

S (3)

(B: pd)

Eq.

(B: pd)^b

(A: pl)

O (4)

^aEq. means that the structure is in equilibrium. ^bIt could be somewhat in equilibrium with (A: pl).

7490 | Dalton Trans., 2012, 41, 7485–7497

This journal is © The Royal Society of Chemistry 2012

View Article Online

Table 5 Selected structural information and energies of optimized structures of 1-(PhTe)C₁₀H₇(1a) at the MP2 level^a

d

Structure

A

TS-AB′^b

B′^c

B_o

E (au)

−7226.8627

0.0^e

2.1097

2.1121

95.63

62.92

38.15

22.2 (A)

26.6 (A)

0.2275

0.1831

−7226.6796

0.0^e

−7226.8604

5.9

2.1177

2.1097

94.22

120.07

−54.75

−11.7 (A)

16.5 (A)

0.2269

0.1839

−7226.6765

8.0

−7226.8613

3.5

2.1207

2.1042

95.82

174.68

−88.08

4.5 (A)

30.1 (A)

0.2273

0.1814

−7226.6799

−0.8

−7226.8613

3.6

2.1206

2.1042

95.84

ΔE (kJ mol⁻¹

r(Te, C₁) (Å)

)

r(Te, C₁₁) (Å)

∠C₁TeC₁₁(°)

∠C₁₀C₁TeC₁₁(°)

∠C₁TeC₁₁C₁₂(°)

180.00

−89.94

−306.4 (A′′)

−1.2 (A′′)

0.2260

0.1838

−7226.6775

5.4

ν₁^f(sym) (cm⁻¹

)

ν₂^g(sym) (cm⁻¹

ZC^h(au)

GFⁱ(au)

j

E_GF(au)

ΔE_GF(kJ mol⁻¹

)

^aThe basis sets of the (7433111/743111/7411/2 + 1s1p1d1f) type were employed for Te with the 6-31G(d,p) basis sets for C and H. ^bTransition state

between A and B′. ^cCloser to B. ^dCorresponding to higher TS with two imaginary frequencies. ^eTaken as the standards for the energies. ^fLowest

frequency obtained by the frequency analysis. ^gSecond-lowest frequency obtained by the frequency analysis. ^hZero-point correction. ⁱThermal

correction to Gibbs free energy at 298.15 K. ^jSum of electronic and thermal Gibbs free energies at 298.15 K.

Table 6 Selected structural information and energies of 1-(PhSe)C₁₀H₇(2a) at the MP2 level^a

d

Structure

A

TS-AB′^b

B′

TS-B′B′^c

B_o

E (au)

−3015.0774

0.0^e

1.9191

1.9231

98.11

66.59

40.31

25.1 (A)

27.5 (A)

0.2282

0.1849

−3014.8925

0.0^e

−3015.0751

5.9

1.9293

1.9181

97.31

136.92

−66.86

−7.3 (A)

25.5 (A)

0.2279

0.1864

−3014.8887

10.1

−3015.0751

5.9

1.9297

1.9164

97.89

150.23

−73.16

6.3 (A)

29.6 (A)

0.2281

0.1835

−3014.8917

2.2

−3015.0750

6.2

1.9298

1.9145

99.04

179.35

−91.33

−8.3 (A)

29.7 (A)

0.2283

0.1870

−3014.8880

11.9

−3015.0750

6.4

1.9298

1.9144

99.05

ΔE (kJ mol⁻¹

r(Se, C₁) (Å)

)

r(Se, C₁₁) (Å)

∠C₁SeC₁₁(°)

∠C₁₀C₁SeC₁₁(°)

∠C₁SeC₁₁C₁₂(°)

180.00

−90.71

−375.7 (A′′)

−9.0 (A′′)

0.2266

0.1853

−3014.8897

7.7

ν₁^f(sym) (cm⁻¹

)

ν₂^g(sym) (cm⁻¹

ZC^h(au)

GFⁱ(au)

j

E_GF(au)

Δ_GF(kJ mol⁻¹

)

^aThe 6-311+G(3d) basis sets were employed for Se with the 6-31G(d,p) basis sets for C and H. ^bTransition state between A and B′, where B′ is very

close to C′. ^cTransition state between B′ and the topological isomer. ^dCorresponding to higher TS with two imaginary frequencies. ^eTaken as the

standards for the energies. ^fLowest frequency obtained by the frequency analysis. ^gSecond-lowest frequency obtained by the frequency analysis.

^hZero-point correction. ⁱThermal correction to Gibbs free energy at 298.15 K. ^jSum of electronic and thermal Gibbs free energies at 298.15 K.

notation is employed instead of B for 1a–4a, since B becomes

closer to C for Y of non-H in 1–4. The structure should be called

B′ and it is convenient when the structures of 1–4 are discussed

in a uniﬁed form. Structures are also optimized assuming the C_s

symmetry with ∠C₁₀C₁ZC₁₁= 180.00° for 1a–4a, which are

called B_o. Structures converged to B′, when optimizations are

started around B_ofor 1a–4a. Tables 5 and 6 contain the data for

A, B′ and B_o, together with the transition state between A and

B′ (TS-AB′).

The B_ostructure is not the transition state between B′ and the

topological isomer, since it has two imaginary frequencies for

each of 1a–4a. The transition state of TS-B′B′ was optimized for

each of 2a and 4a, of which ∠C₁₀C₁ZC₁₁is about 179.4°.

However, the transition state of TS-B′B′ was not optimized for

1a and 3a. The transition state was converged to TS-AB′, even

when the optimization is started from ∠C₁₀C₁ZC₁₁of around

179.4° for 1a and 3a.

energy difference between B′ and A (ΔE(B′A) = E(B′) − E(A))

in 4a is predicted to be 1.4 kJ mol⁻¹. The results are in accord-

ance with the observed structure of 4a in crystals (see Fig. 4).

The ΔE(B′A) values becomes larger and up to 6–7 kJ mol⁻¹for

2a and 3a. It seems difﬁcult to examine the predicted values,

since the structures of 1a–3a are not determined by the X-ray

crystallographic analysis, due to the oily nature around room

temperature. It seems somewhat strange, since the energy level

of TS-AB′ is predicted to be very close to that of B′ for 2a.

On the other hand, the energy proﬁles become reasonable if

the thermal correction by the Gibbs free energy at 298.15 K is

taken into account. The ΔE_GF(B′A) values are predicted to be

−1.0–2.5 kJ mol⁻¹for 1a–4a, which support the equilibrium

between A and B′ in solutions. They could be observed for both

A and B′ in crystals. The predicted energy barriers for TS-AB′

and TS-B′B′ are 4–12 kJ mol⁻¹for 1a–4a, which separate A

and B′ reasonably. Namely, the energy proﬁles on the energy

potential surface are well-improved by the thermal energy of the

Gibbs free energy for 1a–4a, although the effect on TS-B′B′

could not be clariﬁed for 1a and 3a.

Fig. 8a and b show the energy proﬁles for 1a–4a, evaluated

on the potential energy surface and those with the thermal cor-

rection to Gibbs free energy at 298.15 K, respectively. The

This journal is © The Royal Society of Chemistry 2012

Dalton Trans., 2012, 41, 7485–7497 | 7491

View Article Online

The ∠C₁₀C₁ZC₁₁and ∠C₁ZC₁₁C₁₂values will change

depending on Z and Y (see Scheme 3). Fig. 9a and b show the

plots of ∠C₁₀C₁ZC₁₁and ∠C₁ZC₁₁C₁₂versus Y, respectively,

separately by the types of structures. The ∠C₁₀C₁ZC₁₁values of

A are 62.5–64.8°, 66.0–68.3°, 67.0–69.3° and 75.8–80.3° for

1–4, respectively (see Table 7). The values are rather constant or

increase slightly as the accepting ability of Y becomes larger. On

the other hand, the ∠C₁₀C₁ZC₁₁values of B′ change dramati-

cally depending on Y, as shown in Fig. 9a (and Table 7). The B′

structures are (very) close to B_ofor 1b′–4b′. However,

∠C₁₀C₁ZC₁₁decreases as the accepting ability of Y increases. In

this process, B′ converges to A via C at 3f, 1j, 2j and 4j. The

results strongly support the observed results in solutions: the A

structure is predicted for 1–4 with Y of accepting ability stronger

than Cl. The change of ∠C₁ZC₁₁C₁₂is well-correlated to that of

∠C₁₀C₁ZC₁₁, as shown in Fig. 9b.

What are the energy proﬁles of 1 and 2 with Y of a, b′, d, f

and j? The energy differences between the p(Z)–π(C₆H₄Y) and

p(Z)–π(Nap) conjugations (ΔE_pπ(Z : Y) = E(p(Z)–π(Nap)) −

E(p(Z)–π(C₆H₄Y))) can be roughly estimated through the energy

differences between A_oand B_o. However, we must be careful

when the energy proﬁles are examined, since the data in Table 7

are evaluated on the energy potential surface. How can the

thermal effect be incorporated? The thermal effect could be

approximately incorporated by employing the values given in

Fig. 8b as the standard for 1a–4a, if the thermal effect on Y is

not so different in A and B and the related structures. Fig. 10a

and b draw the relative values of ΔE_pπ(Z : Y) for those between

A_oand B_o, and between A and B′, respectively.

The ΔE_pπ(Z : Y) values between A_oand B_oare all about

−5 kJ mol⁻¹for 1–4 when Y of b′. The values become monoto-

nically larger as the accepting ability of Y increases and ﬁnally

(over) +5 kJ mol⁻¹at Y of j. The trend in ΔE_pπ(Z : Y) between

A and B′ is essentially the same as those between A_oand B_o,

although ΔE_pπ(Z : Y) for Z = S and Se with Y of b′ seems

smaller, which must be due to the employed standard values of

2.2–2.5 kJ mol⁻¹, instead of −1 kJ mol⁻¹, for the compounds.

Very large values are predicted for 3f and 1j–4j, which arise

from the structural convergence to A in the compounds. The

results demonstrate that the p–π conjugation operates effectively

for Z of heavier atoms, such as Se and Te, as well as O and S.

After clariﬁcation of the energy proﬁles of 1–4, the role of the

p(Z)–π(Ar/Nap) conjugation in the ﬁne structures is next exam-

ined employing NBO analysis.

Fig. 8 Energy proﬁles for 1a–4a evaluated on the potential energy

surface (a) and considering the Gibbs free energy at 298 K (b).

The ∠C₁₀C₁ZC₁₁values of A in 1a–4a are 62.92°, 66.59°,

67.48° and 77.82°, respectively. The values increase monotoni-

cally in the order of 1a (Z = Te) < 2a (Se) < 3a (S) < 4a (O).

The order seems inverse to the C–Z bond lengths. The π–π inter-

action may occur more easily between naphthyl and phenyl

planes as the C–Z bond becomes longer, as shown by the

∠C₁₀C₁ZC₁₁values. The ∠C₁₀C₁ZC₁₁values of B′ are 174.68°,

150.23°, 163.18° and 149.70° for 1a–4a, respectively, and those

of TS-AB′ are 120.07°, 136.93°, 136.38° and 115.92°, respect-

ively. It seems difﬁcult to explain the trends.

Compilation of these results suggests that the structures of

minima and the transition states would change depending on the

electronic environment around Z. This consideration led us to

clarify the structures and energy proﬁles in more detail for 1–4

that have Y of non-H.

p(Z)–π(Ar/Nap) conjugations in 1–4 evaluated by NBO

NBO (natural bond orbital)²⁷analysis was applied to A_oand B_o

of 1a–4a, 1b′, 1d, 1f and 1j. However, the (A: pl)_oand (B: pd)_o

notation is employed here, instead of A_oand B_o, respectively,

since it is inevitable to deﬁne the conformation around the

p-YC₆H₄Z group to evaluate the p(Z)–π(Ar/Nap) conjugation.

Magnitudes of the p–π conjugation of the n_p(Z)→π*(Nap) and

n_p(Z)→π*(Ar) types were evaluated for Z = Te, Se, S and O in

1–4.

Such p–π conjugation can be obtained as the CT interactions

of which magnitudes are evaluated as the second order pertur-

bation of the Fock matrix in NBO. For each donor NBO (i) and

acceptor NBO ( j), the stabilization energy E(2) associated with

Features in structures of 1-(p-YC₆H₄Z)Nap (1–4)

The A_ostructure was obtained by optimizing partially with the

torsional angles being ﬁxed at ∠C₁ZC₁₁C₁₂= 0.00°, similar to

the case of B_oof which ∠C₁₀C₁ZC₁₁is ﬁxed at 180.00°. The

A_oand B_ostructures were calculated for 1–4 with Y of H (a),

NH₂(b′), Me (d), Cl (f) and NO₂(j), for a better understanding

of the p–π conjugation. Table 7 collects the results of calculations

for 1 and 2. Those for 3 and 4 are given in Table S4 of the ESI.†

7492 | Dalton Trans., 2012, 41, 7485–7497

This journal is © The Royal Society of Chemistry 2012

View Article Online

Table 7 Selected structural information and energies of 1 and 2 that have p-Y of NH₂(b′), Me (d), H (a), Cl (f) and NO₂(j) calculated at the MP2

level^a,b

Compound/Y =

NH₂(b′)

Me (d)

H (a)

Cl (f)

NO₂(j)

1: 1-(p-YC₆H₄Te)C₁₀H₇

∠C₁₀C₁TeC₁₁(A) (°)

∠C₁TeC₁₁C₁₂(A) (°)

∠C₁₀C₁TeC₁₁(B′) (°)

∠C₁TeC₁₁C₁₂(B′) (°)

∠C₁₀C₁TeC₁₁(A_o) (°)

∠C₁TeC₁₁C₁₂(A_o) (°)

∠C₁₀C₁TeC₁₁(B_o) (°)

∠C₁TeC₁₁C₁₂(B_o) (°)

E(A)^d(au)

63.26

53.71

178.25

−90.08

72.91

62.51

40.40

176.61

−88.91

72.97

0.00

180.00

−89.62

−7266.0487

as 0.0

2.9

62.92

38.15

174.68

−88.08

73.13

0.00

180.00

−89.92

−7226.8627

as 0.0

3.5

63.10

36.84

171.31

−86.01

73.03

0.00

180.00

−89.99

−7685.8835

as 0.0

4.3

64.83

26.87

64.83^c

26.88^c

73.13

0.00

180.00

−90.11

−7430.8558

as 0.0

0.0^c

0.00

180.00

−90.09

−7282.0654

as 0.0

0.5

as 0.0

−4.1

ΔE(A)^e(kJ mol⁻¹

ΔE(B′)^e(kJ mol⁻¹

ΔE(A_o)^e(kJ mol⁻¹

ΔE(B_o)^e(kJ mol⁻¹

)

as 0.0

0.0

as 0.0

0.9

as 0.0

1.9

as 0.0

6.5

2: 1-(p-YC₆H₄Se)C₁₀H₇

∠C₁₀C₁SeC₁₁(A) (°)

∠C₁SeC₁₁C₁₂(A) (°)

∠C₁₀C₁SeC₁₁(B′) (°)

∠C₁SeC₁₁C₁₂(B′) (°)

∠C₁₀C₁SeC₁₁(A_o) (°)

∠C₁SeC₁₁C₁₂(A_o) (°)

∠C₁₀C₁SeC₁₁(B_o) (°)

∠C₁SeC₁₁C₁₂(B_o) (°)

E(A)^d(au)

65.99

50.41

173.37

−88.34

75.28

66.23

42.40

155.90

−77.59

75.51

0.00

180.00

−90.47

−3054.2633

as 0.0

5.5

66.59

40.31

150.24

−73.16

75.69

0.00

180.00

−90.71

−3015.0774

as 0.0

5.9

66.88

39.09

93.99^c

47.39^c

75.64

0.00

180.00

−90.77

−3474.0982

as 0.0

4.1^f

68.28

29.05

68.28^c

29.05^c

75.77

0.00

180.00

−90.92

−3070.2797

as 0.0

3.1

as 0.0

−1.9

180.00

−90.86

−3219.0709

as 0.00

0.0^c

as 0.0

9.4

ΔE(A)^e(kJ mol⁻¹

ΔE(B′)^e(kJ mol⁻¹

ΔE(A_o)^e(kJ mol⁻¹

ΔE(B_o)^e(kJ mol⁻¹

)

as 0.0

2.4

as 0.0

3.4

as 0.0

4.5

^aThe basis sets of the (7433111/743111/7411/2 + 1s1p1d1f) type were employed for Te with the 6-31G(d,p) basis sets for C and H. ^bA stationary

point was not obtained for typical B. ^cThe value is almost the same if the thermal effect is considered, but it becomes −8.4 kJ mol⁻¹if the solvent

effect is calculated by the IPCM method. ^dΔE = E(A) − E(B). ^eA. ^fA′.

magnitudes increase in the order of Z = Te < Se < S < O. It is

worthwhile to note that the ΔE(2) values (= E(2: (B: pd)_o) −

E(2: (A: pl)_o)) decrease to 0.42, 0.75, 1.41 and 2.91 kcal mol⁻¹

for 1a–4a, respectively. The ΔE(2) values control the appearance

of (A: pl)_oor (B: pd)_oin crystals and the predominance in equi-

librium in solutions, although other factors, such as the crystal

packing effect in crystals, solvent effect in solutions and the

steric effect in the conformers must be taken into account. The Y

dependence of ΔE(2) is also of very interest. The values are eval-

uated to be 1.75, 0.78, 0.42, −0.05 and −2.32 kcal mol⁻¹for

1b′, 1d, 1a, 1f and 1j, respectively. The values decrease in the

order of Y = NH₂(b′) > Me (d) > H(a) > Cl(f) > NO₂( j). The

results of NBO explain the experimentally observed ones well.

How do n_p(Z) interact effectively with π-orbitals of naphthyl

and aryl groups in (A: pl) and (B: pd)? Such interactions can be

exempliﬁed by the HOMO of 1a. Fig. 11 shows the HOMO of

1a for (A: pl)_oand (B: pd)_o. As shown in Fig. 11, n_p(Te) of the

HOMOs for (A: pl)_oand (B: pd)_oin 1a are placed on the

naphthyl and phenyl planes, respectively. This means that n_p(Te)

of the HOMO extends easily over π*(Ph) in (A: pl)_oand π*-

(Nap) in (B: pd)_o. The results show that the n_p(Te)→π*(Ar)

interaction contributes predominantly in (A: pl)_o, while

n_p(Te)→π*(Nap) is in (B: pd)_o. The results for (A: pl) and

(B: pd) are essentially the same as those for (A: pl)_oand

(B: pd)_o, respectively, although these are not shown.

Scheme 3 Structures of A and B with atomic numbering used for the

torsional angles.

delocalization was estimated by eqn (1), where q_iis the donor

orbital occupancy, ε_jand ε_iare diagonal elements (orbital ener-

gies) and F(i, j) is the off-diagonal NBO Fock matrix element.

2

Eð2Þ ¼ ΔE_ij¼ q_iFði; jÞ =ðε_jꢀ ε_iÞ

ð1Þ

Table 8 collects the results at the MP2 level. Donor orbitals of

NBO (i) in 1–4 correspond to n_p(Z), where Z = Te, Se, S and O,

respectively. On the other hand, acceptor orbitals of NBO ( j)

depend on the structures of 1–4. While a σ*(C₁vC₂) in the

naphthyl group acts as NBO ( j) for each (B: pd)_oin the calcu-

lations, NBO ( j) will be a σ*(C₁₁vC₁₂) in the aryl groups for

(A: pd)_o, as shown in Scheme 3. The E(2) values for [(A: pl)_o;

(B: pd)_o] are evaluated as [12.58; 13.00], [17.70; 18.45], [24.02;

25.43] and [30.64; 33.55] in kcal mol⁻¹for 1a–4a, respectively.

The results show that the p–π conjugation of the n_p(Z)→π*(Ar/

Nap) types operates effectively, even for Z = Te, although the

While the ∠C₁₀C₁TeC₁₁and ∠C₁TeC₁₁C₁₂values were pre-

dicted to be 73.13° and 0.00°, respectively, for 1a (A: pl)_o, the

Dalton Trans., 2012, 41, 7485–7497 | 7493

View Article Online

Fig. 9 Structural changes in 1–4 along with Y = NH₂, Me, H, Cl and

NO₂in ∠C₁₀C₁ZC₁₁(a) and in ∠C₁ZC₁₁C₁₂(b).

Fig. 10 The ΔE_pπ(Z : Y) values between type A_oand type B_o(a) and

between type A and type B′ (b). The thermal effect is contained in (b),

which is evaluated employing ΔE_pπ(Z : H) given in Fig. 8b.

values changed to 62.92° and 38.15°, respectively, for the fully

optimized structure of 1a (A: np). The HOMO would extend

over both π*(Ph) and π*(Nap) in 1a (A: np). However, the

∠C₁₀C₁TeC₁₁and ∠C₁TeC₁₁C₁₂values were experimentally

determined to be 94.52(2)° and −10.95(2)°, respectively, for 1i.

The structure of 1i can be well-described by (A: pl)_o, as shown

in Fig. 3. Consequently, the p–π conjugation operates practically

in 1 and controls the ﬁne structures of 1.

The crystal packing effect would deform the molecular struc-

tures in crystals and the solvent effect affects on the relative stab-

ilities of conformers. Therefore, we must be careful when

phenomena arising from weak interactions are analyzed with

causality. The over-estimation of weak interactions in the MP2

calculations must also be considered when such phenomena are

calculated at the MP2 level, although this level is highly

reliable.²⁸

Structural determinations in solutions were successfully per-

formed on 2 employing NMR data of 5 and 6. Similar determi-

nations in solutions were also successful in 1. However, some

deviations were detected when δ(Te)_SCSwere plotted versus

δ(Se:)_SCS, employing the same structures for the Te and Se

derivatives. Sets of standards for δ(Te)_SCSare inevitably similar

to the case of δ(Se:)_SCS. The Te analogues of 5 and 6 (5′ and 6′,

respectively) would be the candidates for the standards. Such

investigations on δ(Te)_SCSare in progress, although the accurate

estimation of the relativistic effect on δ(Te) must also be necess-

ary to accomplish the purpose.

Conclusion

1-(Arylchalcogena)naphthalenes

[1-(p-YC₆H₄Z)C₁₀H₇:

1

(Z = Te), 2 (Z = Se), 3 (Z = S) and 4 (Z = O)] must be the key

compounds to generate speciﬁc structures, to design particular

kinds of interactions and to create delicate properties in materials

for the derivatives of 1–4. Reactions of the derivatives with

metals and/or halogens must also be of much interest. To deter-

mine the ﬁne structures and to clarify the factors that control the

ﬁne structures of 1–4 is the ﬁrst step for a better understanding

of the compounds. The p–π conjugation of the p(Z)–π(Ar/Nap)

type is the most signiﬁcant factor to control the structures of

1–4. The role of p(Te)–π(Ar/Nap) conjugation is established as

the factor to control the ﬁne structures of 1 in the same accuracy

for 2–4 in the uniﬁed form, after determination of the ﬁne struc-

tures of 1 in crystals and solutions. NMR chemical shifts of 9-

(arylselanyl)anthracenes (5) and 1-(arylselanyl)anthraquinones

(6) serve as the sets of standards for pl and pd, respectively, in

solutions. However, we encountered some speciﬁc observations

in 1 relative to the case of 2. The discrepancy between δ(Te) in 1

and δ(Se) in 2 seems not be eliminated unless the behavior of

δ(Te) in 1 is clariﬁed by using the sets of standards. The Te

derivatives of 5 and 6 (5′ and 6′, respectively) will be the candi-

dates for the standard compounds, although preparations of 5′

and 6′ are still in progress.

QC calculations supplied the crucial information for the

energy proﬁles of 1–4. The energy proﬁles become much more

7494 | Dalton Trans., 2012, 41, 7485–7497

View Article Online

Table 8 Results of NBO analysis for the n_p(Z)→π*(Ar/Nap) conjugation in (A: pl)_oand (B: pd)_oof 1a–4a, 1b′, 1d, 1f and 1j^a,b,c,d

Compound

Structure

NBO (i)

NBO (j)

E(2)^e

ΔE(2)^e

E(i,j)^f

F(i,j)^f

1a

1b′

1d

1f

(A: pl)_o

(B: pl)_o

(A: pl)_o

(B: pl)_o

(A: pl)_o

(B: pl)_o

(A: pl)_o

n_p(Te)

n_p(Se)

n_p(S)

σ*(C₁₁vC₁₂: Ph)

σ*(C₁₁vC₁₂: Ar)

σ*(C₁vC₂: Nap)

σ*(C₁₁vC₁₂: Ph)

σ*(C₁vC₂: Nap)

σ*(C₁₁vC₁₂: Ph)

σ*(C₁vC₂: Nap)

σ*(C₁₁vC₁₂: Ph)

σ*(C₁vC₂: Nap)

12.58

11.23

12.24

12.92

15.02

13.00

12.98

13.02

12.87

12.70

17.70

18.45

24.02

25.43

30.64

33.55

0.00

0.42

1.75

0.78

−0.05

−2.32

0.00

0.75

0.00

1.41

0.00

2.91

0.46

0.48

0.49

0.51

0.53

0.68

0.70

0.074

0.070

0.073

0.074

0.079

0.075

0.074

0.090

0.091

0.106

0.109

0.138

0.143

1j

1a

1b′

1d

1f

1j

2a

3a

4a

n_p(S)

n_p(O)

^aG(l) with Y = H (a) and Me (d); G(m) with Y = NMe₂(b), OMe (c) and F (e); G(n) of Y = Cl (f), Br (g), COOEt (h), CN (i) and NO₂(j). ^bG(m*)

of Y = NMe₂(b) and OMe (c). ^cG(m′) with Y = H (a), OMe (c) and Me (d). ^dG(n′) with Y = Cl (f), Br (g), COOEt (h) and NO₂(j).

^fIn kcal mol⁻¹. ^fIn au.

in parts per million relative to those of Me₄Si, internal CDCl₃in

the solvent and external Me₂Te, respectively. Flash column

chromatography was performed with 300–400 mesh silica gel

and analytical thin layer chromatography was performed on pre-

coated silica gel plates (60F-254) with the systems (v/v)

indicated.

Fig. 11 Orbital interactions in 1a. The HOMOs of (A: pl)_o(a) and

1-[p-(N,N-Dimethylamino)phenyltellanyl]naphthalene (1b)

(B: pd)_o(b).

Under a nitrogen atmosphere, to a suspension of 1,1′-diphenyl

ditelluride (1.00 g, 1.96 mmol) and 40 mL of THF at 3–5 °C

reasonable if corrected thermally by the Gibbs free energy evalu-

was added NaBH₄(0.30 g, 7.85 mmol) in a small amount of

ated at 298.15 K, although those on the potential energy surface

water. A solution of 6.0 equiv. of p-(N,N-dimethylamino)phenyl-

must also be intrinsic. Magnitudes of the p(Z)–π(Ar/Nap) conju-

diazonium chloride was added at 3–5 °C. Benzene (200 mL)

gation were well-evaluated by NBO analysis. The p(Z)–π(Ar/

was added. The organic layer was separated and washed with

Nap) conjugation is demonstrated to operate effectively for

10% aqueous solution of sodium bicarbonate and saturated

Z = Te, as well as Z = O, S and Se. The substituent effect on the

aqueous solution of sodium hydrogen carbonate and dried over

p(Te)–π(Ar/Nap) conjugation in 1 substantially explains the

sodium sulfate. The crude product was puriﬁed by ﬂash column

observed results. Such conjugation in 1a can be imaged well by

chromatography (SiO₂, benzene as eluent) and recrystallization

examining how HOMO of n_p(Te) extends over π(Ar) and π(Nap)

in the structures of (A: pl)_oand (B: pd)_o, although they are

typical conformers in 1a. The results of the calculations show a

guideline to analyze the interactions containing heavier atoms.

Interactions with heavier atoms could be analyzed similarly to

the cases with usual atoms for those of the p–π conjugation.

from n-hexane. 1b was isolated in 28% yield as yellow needles

1

(410 mg): mp 84.5–85.5 °C; H NMR (400 MHz, CDCl₃, δ,

ppm, TMS) 2.97 (s, 6H), 6.62 (d, J = 8.9 Hz, 2H), 7.20 (dd, J =

7.3 Hz and 8.0 Hz, 1H), 7.45–7.54 (m, 2H), 7.59 (dd, J = 1.0

Hz and 7.1 Hz, 1H), 7.69–7.74 (m, 3H), 7.78 (dd, J = 1.6 Hz

and 7.7 Hz, 1H), 7.96 (dd, J = 1.0 Hz and 8.1 Hz, 1H); ¹³C

NMR (100 MHz, CDCl₃, δ, ppm, TMS) 40.1 (2C), 96.5, 113.7

Experimental section

(2C), 119.7, 126.0, 126.4, 127.8, 128.6, 130.1, 133.6, 134.6,

135.2, 141.6 (²J(Te,C) = 23.0 Hz, 2C), 150.5; ¹²⁵Te NMR

(126 MHz, CDCl₃, δ, ppm, Me₂Te) 538.3. Anal. calc. for

C₁₈H₁₇NTe; C, 57.66; H, 4.57; N, 3.74%. Found: C, 57.61; H,

4.53; N, 3.70%.

General considerations

Manipulations were performed under an argon atmosphere with

standard vacuum-line techniques. Glassware was dried at 130 °C

overnight. Solvents and reagents were puriﬁed by standard pro-

cedures as necessary. The melting points were determined on a

Yanako MP-S3 melting point apparatus and are uncorrected.

NMR spectra were recorded at 25 °C on a JEOL JNM-ECA 400

spectrometer (¹H, 400 MHz; ¹³C, 100 MHz: ¹²⁵Te, 126 MHz) in

CDCl₃solution. The ¹H, ¹³C and ¹²⁵Te chemical shifts are given

1-(p-Fuluorophenyltellanyl)naphthalene (1e)

Under a nitrogen atmosphere, to a solution of 1-bromonaphtha-

lene (1.50 g, 4.83 mmol) in 20 mL of THF at −78 °C was added

3.1 mL of n-BuLi (5.05 mmol, 1.65 N). After being stirred for

Dalton Trans., 2012, 41, 7485–7497 | 7495

View Article Online

0.5 h, a THF solution of 1.0 equiv. of phenyltellanylbromide

was added to the 1-naphthyllithium solution. After being stirred

for 2 h at −78 °C, the reaction was quenched by 4 mL of

acetone. The crude product was puriﬁed by ﬂash column chrom-

atography (SiO₂, n-hexane) and recrystallized from n-hexane.

Compound 1e was isolated in 22% yield as a pale yellow oil

838257 for 1b, CCDC 838258 for 1c and CCDC-838259 for 1i

contain the supplementary crystallographic data for this paper.†

QC calculations

1a–4a, 1b′–4b′, 1c–4c, 1f–4f and 1j–4j were optimized and the

frequency analysis was performed on the optimized structures

using the Gaussian 03 program.²⁴The Møller–Plesset second-

order energy correlation (MP2) level was applied to the calcu-

lations²³with the 6-311+G(3d) basis sets³¹for O, S and Se, the

(7433111/743111/7411/2 + 1s1p1d1f) basis sets³²for Te and

with the 6-31G(d,p) basis sets for C and H.

1

(368 mg): H NMR (400 MHz, CDCl₃, δ, ppm, TMS) 6.89 (t,

J = 8.9 Hz, 2H), 7.28 (dd, J = 7.1 Hz and 8.1 Hz, 1H),

7.47–7.54 (m, 2H), 7.63 (dd, J = 5.6 Hz and 8.8 Hz, 1H),

7.78–7.85 (m, 2H), 7.88 (dd, J = 1.1 Hz and 7.1 Hz, 1H), 8.08

(d, J = 7.6 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃, δ, ppm, TMS)

108.1 (⁴J(C,F) = 2.9 Hz), 116.9 (²J(C,F) = 21.1 Hz, 2C), 117.9,

126.3, 126.5, 127.0, 128.8, 129.4; 131.3, 133.7, 135.6, 138.1,

140.0 (³J(C,F) = 7.7 Hz, 2C), 162.9 (¹J(C,F) = 247.2 Hz); ¹²⁵Te

NMR (126 MHz, CDCl₃, δ, ppm, Me₂Te) 572.1. Anal. calc. for

C₁₆H₁₁FTe; C, 54.93; H, 3.17%. Found: C, 54.88; H, 3.19%.

Acknowledgements

This work was partially supported by a Grant-in-Aid for Scien-

tiﬁc Research (Nos. 19550041 and 20550042) from the Ministry

of Education, Culture, Sports, Science and Technology, Japan.

The support of the Wakayama University Original Research

Support Project Grant and the Wakayama University Graduate

School Project Research Grant is also acknowledged.

1-(p-Cyanophenyltellanyl)naphthalene (1i)

Following the procedure used for the preparation of 1b, 1i was

1

obtained in 46% yield as colorless solid: mp 64.9–65.9 °C; H

NMR (400 MHz, CDCl₃, δ, ppm, TMS) 7.29 (d, J = 8.2 Hz,

2H), 7.38 (dd, J = 7.2 Hz and 8.1 Hz, 1H), 7.42 (d, J = 8.2 Hz,

2H), 7.48–7.56 (m, 2H), 7.85 (dd, J = 1.5 Hz and 6.9 Hz, 1H),

7.97 (d, J = 8.1 Hz, 1H), 8.16 (dd, J = 2.5 Hz and 6.5 Hz, 1H),

8.21 (dd, J = 1.0 Hz and 7.0 Hz, 1H); ¹³C NMR (100 MHz,

CDCl₃, δ, ppm, TMS) 110.3, 116.0, 118.7, 124.5, 126.6, 126.7,

127.7, 129.0, 131.2, 132.2 (2C), 132.3, 133.7, 135.0 (²J(Te,C) =

26.0 Hz, 2C), 135.9, 141.6; ¹²⁵Te NMR (126 MHz, CDCl₃, δ,

ppm, Me₂Te) 596.1. Anal. calc. for C₁₇H₁₁NTe; C, 57.21; H,

3.11; N, 3.92%. Found: C, 57.16; H, 3.19; N, 3.88%.

Notes and references

1 W. MacFarlane and R. J. Wood, J. Chem. Soc., Dalton Trans., 1972, 13,

1397–1401.

2 H. Iwamura and W. Nakanishi, J. Synth. Org. Chem., Jpn., 1981, 39,

795–804.

3 The Chemistry of Organic Selenium and Tellurium Compounds, ed.

S. Patai and Z. Rappoport, John-Wiley and Sons, New York, 1986, ch. 6,

vol. 1.

4 Compilation of Reported ⁷⁷Se NMR Chemical Shifts, ed. T. M. Klapotke

and M. Broschag, Wiley, New York, 1996.

5 H. Duddeck, Prog. Nucl. Magn. Reson. Spectrosc., 1995, 27, 1–323.

6 The p(Z)–π(Ar/Nap) conjugation in 1–4 seems substantially strong,

however, it is often difﬁcult to explain the observed bond lengths on the

basis of the conjugation. The changes are sometimes observed in the

inverse direction due to other factors affecting the lengths, of which the

magnitudes are sometimes stronger than that of the conjugation. Instead,

the orientation around Z is well-controlled by the conjugation for 1–4.

The reliable geometry can be obtained from high resolution multipole

reﬁnement of electron density and the experimental errors associated with

routine structural investigations may be responsible for the observations

in some cases. We must examine the structures in crystals and solutions

very carefully with the guidance of accurate calculations, to demonstrate

the causality between the p(Z)–π(Ar/Nap) conjugation and the observed

structural features. We need to avoid the superﬁcial factors operating

behind the real one through the careful analysis. We have called such

structures under the conditions ﬁne structures, as with those of 1–4 in the

text.

7 S. Gronowitz, A. Konar and A.-B. Hörnfeldt, Org. Magn. Res., 1977, 9,

213–217.

8 G. P. Mullen, N. P. Luthra, R. B. Dunlap and J. D. Odom, J. Org. Chem.,

1985, 50, 811–816.

9 G. A. Kalabin, D. F. Kushnarev, V. M. Bzesovsky and G. A. Tschmutova,

J. Org. Magn. Res., 1979, 12, 598–604.

10 G. A. Kalabin, D. F. Kushnarev and T. G. Mannafov, Zh. Org. Khim.,

1980, 16, 505–512.

X-ray structure determination

Single crystals of 1b, 1c and 1i were obtained from solutions of

n-hexane after slow evaporation of the solvent at room tempera-

ture. Diffraction data for 1b, 1c and 1i were performed at 93(2)

K with the use of a RIGAKU CCD SATURN 724 diffractometer

with a graphite-monochromated MoKα radiation source (λ =

0.71073 Å). The structures were solved by direct methods

(SHELXS-97)²⁹and reﬁned by full-matrix least-square methods

on F²for all reﬂections (SHELXL-97),³⁰with all non-hydrogen

atoms anisotropic and all hydrogen atoms isotropic. For 1b, the

structure analysis is based on 3447 observed reﬂections with

I > 2.00σ(I) and 249 variable parameters; colorless prisms, 93(2)

K, monoclinic, space group P2₁/n (#14), a = 7.437(4) Å, b =

19.619(9) Å, c = 10.378(5) Å, β = 95.950(8)°, V = 1506.1(13)

Å³, Z = 4, R = 0.0311, R_W= 0.0458, GOF = 0.974. For 1c the

structure analysis is based on 2976 observed reﬂections with

I > 2.00σ(I) and 228 variable parameters; colorless prisms, 93(2)

K, monoclinic, space group P2₁/c (#14), a = 7.741(3) Å, b =

22.180(9) Å, c = 8.551(4) Å, β = 109.847(6)°, V = 1381.0(10)

Å³, Z = 4, R = 0.0245, R_W= 0.0659, GOF = 1.125. For 1i, the

structure analysis is based on 2914 observed reﬂections with

I > 2.00σ(I) and 216 variable parameters; colorless prisms, 93(2)

K, monoclinic, space group P2₁/c (#14), a = 14.8180(13) Å, b =

5.5614(5) Å, c = 16.5413(12) Å, β = 96.886(5)°, V = 1353.3(2)

Å³, Z = 4, R = 0.0209, R_W= 0.0525, GOF = 1.079. CCDC

11 W. Nakanishi, S. Hayashi and T. Uehara, Eur. J. Org. Chem., 2001,

3933–3943.

12 (a) S. Hayashi and W. Nakanishi, J. Org. Chem., 1999, 64, 6688–6696;

(b) W. Nakanishi, S. Hayashi and H. Yamaguchi, Chem. Lett., 1996,

947–948; (c) W. Nakanishi, S. Hayashi, A. Sakaue, G. Ono and

Y. Kawada, J. Am. Chem. Soc., 1998, 120, 3635–3640; (d) W. Nakanishi

and S. Hayashi, J. Org. Chem., 2002, 67, 38–48.

13 (a) W. Nakanishi and S. Hayashi, Chem. Lett., 1998, 523–524;

(b) W. Nakanishi and S. Hayashi, J. Phys. Chem. A, 1999, 103, 6074–

6081.

7496 | Dalton Trans., 2012, 41, 7485–7497

View Article Online

14 (a) Organic Selenium Compounds: Their Chemistry and Biology, ed.

D. L. Klayman and W. H. H. Günther, Wiley, New York, 1973; (b) The

Chemistry of Organic Selenium and Tellurium Compounds, ed. S. Patai

and Z. Rappoport, John-Wiley and Sons, New York, 1986, vols. 1 and 2;

(c) Organic Selenium Chemistry, ed. D. Liotta, Wiley-Interscience,

New York, 1987; (d) Organoselenium Chemistry, A practical Approach,

ed. T. G. Back, Oxford University Press, Oxford, 1999;

(e) Organoselenium Chemistry Modern Developments in Organic Syn-

thesis, Top. Curr. Chem., ed. T. Wirth, Springer, Berlin, Heidelberg,

New York, London, Paris, Tokyo, 2000.

15 W. Nakanishi, S. Hayashi and T. Uehara, J. Phys. Chem. A, 1999, 103,

9906–9912.

16 S. Hayashi, H. Wada, T. Ueno and W. Nakanishi, J. Org. Chem., 2006,

71, 5574–5585.

17 (a) S. Hayashi, K. Yamane and W. Nakanishi, J. Org. Chem., 2007, 72,

7587–7596; (b) T. Nakamoto, S. Hayashi and W. Nakanishi, J. Org.

Chem., 2008, 73, 9259–9269.

18 S. Hayashi, T. Nakamoto, M. Minoura and W. Nakanishi, J. Org. Chem.,

2009, 74, 4763–4771.

J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone,

B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson,

H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa,

M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li,

J. E. Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo,

J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin,

R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma,

G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich,

A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck,

K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul,

S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko,

P. Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham,

C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson,

W. Chen, M. W. Wong, C. Gonzalez and J. A. Pople, GAUSSIAN 03

(Revision D.05), Gaussian, Inc., Pittsburgh PA, 2004.

25 NMR chemical shifts at 400 MHz are already reported for 1 with Y = H

(a), OMe (c), Me (d),Cl (f), Br (g), COOEt (h) and NO₂( j). See ref. 21.

26 Investigations to set up the standards of δ(Te)_SCSare in progress, employ-

ing the tellurium derivatives of 5 and 6 or similar compounds.

27 (a) A. E. Reed, R. B. Weinstock and F. Weinhold, J. Chem. Phys., 1985,

83, 735–746; J. E. Carpenter and F. Weinhold, J. Mol. Struct. (THEO-

CHEM), 1988, 169, 41–62; (b) E. D. Glendening, A. E. Reed,

J. E. Carpenter and F. Weinhold, NBO Ver. 3.1.

19 T. Nakai, S. Hayashi and W. Nakanishi, Phosphorus, Sulfur Silicon Relat.

Elem., 2010, 185, 1031–1045.

20 (a) S. M. Aucott, H. L. Milton, S. D. Robertson, A. M. Z. Slawin,

G. D. Walker and J. D. Woollins, Chem.–Eur. J., 2004, 10, 1666–1676;

(b) F. R. Knight, A. L. Fuller, M. Bühl, A. M. Z. Slawin and

J. D. Woollins, Inorg. Chem., 2010, 49, 7577–7596.

28 A. Pavlov and P. M. Mitrasinovic, Curr. Org. Chem., 2010, 14, 129–

138.

21 (a) W. Nakanishi, S. Hayashi, D. Shimizu and M. Hada, Chem.–Eur. J.,

2006, 12, 3829–3846; (b) S. Hayashi and W. Nakanishi, Bioinorg. Chem.

Appl., 2006, DOI: 10.1155/bca/2006/79327.

22 The importance of relative conformations between substituents and probe

sites in the substituent effects is pointed out. See for example,

K. Bordwen and E. J. Grubbs, Angular dependence of dipolar substituent

effects, in Progress in Physical Organic Chemistry, ed. R. W. Taft, John

Wiley & Sons, New York, 1993, vol. 19, pp. 183–224. See also refs cited

therein.

23 (a) C. Mϕller and M. S. Plesset, Phys. Rev., 1934, 46, 618–622;

(b) J. Gauss, J. Chem. Phys., 1993, 99, 3629–3643; (c) J. Gauss, Ber.

Bunsen-Ges, Phys. Chem., 1995, 99, 1001–1008.

24 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb,

J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N. Kudin,

29 G. M. Sheldrick, SHELXS-97, Program for Crystal Structure Solution,

Universität Göttingen, 1997.

30 G. M. Sheldrick, SHELXL-97, Program for Crystal Structure Reﬁnement,

Universität Göttingen, 1997.

31 For the 6-311G(3d) basis sets see, (a) R. C. Binning, Jr. and

L. A. Curtiss, J. Comput. Chem., 1990, 11, 1206–1216; (b) L. A. Curtiss,

M. P. McGrath, J.-P. Blaudeau, N. E. Davis, R. C. Binning, Jr. and

L. Radom, J. Chem. Phys., 1995, 103, 6104–6113; (c) M. P. McGrath

and L. Radom, J. Chem. Phys., 1991, 94, 511–516. For the diffuse func-

tions (+ and ++) see, .T. Clark, J. Chandrasekhar, G. W. Spitznagel and

P. R. von Schleyer, J. Comput. Chem., 1983, 4, 294–301.

32 (a) T. Koga, S. Yamamoto, T. Shimazaki and H. Tatewaki, Theor. Chem.

Acc., 2002, 108, 41–45; (b) M. Sekiya, T. Noro, Y. Osanai and T. Koga,

Theor. Chem. Acc., 2001, 106, 297–300.

Dalton Trans., 2012, 41, 7485–7497 | 7497

Article Doi

Role of p(Z)-π(Ar/Nap) conjugation in structures of 1-(arylchalcogena) naphthalenes for Z = Te versus Se, S and O: Experimental and theoretical investigations

DOI: 10.1039/c2dt30516j

Source and publish data:

Authors:

Article abstract of DOI:10.1039/c2dt30516j

Full text of DOI:10.1039/c2dt30516j

Products guided by the article

R&D Labs maybe for 1383732-45-3

Relevant to this article

Hot Product