1-Phenylethane-1,2-diyl 1,1′-biphenyl-2,2′-dicarboxylate

Fun, H.-K.; Quah, C.K.; Wu, D.

doi:10.1107/S1600536812018065

organic compounds

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ISSN: 2056-9890

Volume 68| Part 5| May 2012| Page o1551

doi:10.1107/S1600536812018065

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1-Phenylethane-1,2-diyl 1,1′-biphenyl-2,2′-dicarboxylate

Hoong-Kun Fun,^a ^*‡ Ching Kheng Quah ^a § and Dongdong Wu ^b

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^bSchool of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, People's Republic of China
^*Correspondence e-mail: hkfun@usm.my

(Received 20 April 2012; accepted 23 April 2012; online 28 April 2012)

In the title compound, C₂₂H₁₆O₄, the 7-phenyl ring is inclined at dihedral angles of 36.73 (9) and 69.37 (9)° with respect to the biphenyl benzene rings. The two benzene rings of the biphenyl unit form a dihedral angle of 55.99 (8)°. There are no significant hydrogen bonds observed in the crystal of this compound.

Related literature

For a related structure, references to other similar structures and chemical and biological background, see: Fun et al. (2012). For the preparation, see: Wu et al. (2012).

Experimental

Crystal data

C₂₂H₁₆O₄
M_r = 344.35
Orthorhombic, P b c a
a = 21.2454 (15) Å
b = 13.2363 (7) Å
c = 12.1954 (7) Å
V = 3429.5 (4) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.27 × 0.22 × 0.08 mm

Data collection

Bruker SMART APEXII DUO CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ) T_min = 0.976, T_max = 0.993
67362 measured reflections
5014 independent reflections
2961 reflections with I > 2σ(I)
R_int = 0.075

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.113
S = 0.99
5014 reflections
235 parameters
H-atom parameters constrained
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812018065/hb6748sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812018065/hb6748Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812018065/hb6748Isup3.cml

checkCIF report

Comment top

As part of our ongoing synthetic and structural studies of bis-lactones containing a biaryl motif (Wu et al., 2012; Fun et al. 2012), we now report the structure of the title compound, (I).

In the title compound, Fig. 1, the terminal benzene ring (C17-C22) inclines at dihedral angles of 36.73 (9) and 69.37 (9)° with the other two benzene rings (C1-C6 and C7-C12), respectively. The two benzene rings form a dihedral angle of 55.99 (8)°.

Related literature top

For a related structure, references to other similar structures and chemical and biological background, see: Fun et al. (2012). For the preparation, see: Wu et al. (2012).

Experimental top

The title compound was the major diastereoisomer of the photoreaction products of 9,10-phenanthrenedione with styrene via a photocycloaddition-photooxidation sequence. The compound was purified by flash column chromatography with ethyl acetate/petroleum ether (1:9) as eluents. Colourless plates of the title compound was obtained from slow evaporation of an acetone and petroleum ether solution (1:10).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

Fig. 1. The molecular structure of the title compound showing 30% probability displacement ellipsoids for non-H atoms.

1-Phenylethane-1,2-diyl 1,1'-biphenyl-2,2'-dicarboxylate top

Crystal data top

C₂₂H₁₆O₄	F(000) = 1440
M_r = 344.35	D_x = 1.334 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 6139 reflections
a = 21.2454 (15) Å	θ = 2.5–24.0°
b = 13.2363 (7) Å	µ = 0.09 mm⁻¹
c = 12.1954 (7) Å	T = 296 K
V = 3429.5 (4) Å³	Plate, colourless
Z = 8	0.27 × 0.22 × 0.08 mm

Data collection top

Bruker SMART APEXII DUO CCD diffractometer	5014 independent reflections
Radiation source: fine-focus sealed tube	2961 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.075
ϕ and ω scans	θ_max = 30.0°, θ_min = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −29→29
T_min = 0.976, T_max = 0.993	k = −18→18
67362 measured reflections	l = −17→17

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.113	H-atom parameters constrained
S = 0.99	w = 1/[σ²(F_o²) + (0.0382P)² + 0.8815P] where P = (F_o² + 2F_c²)/3
5014 reflections	(Δ/σ)_max = 0.001
235 parameters	Δρ_max = 0.16 e Å⁻³
0 restraints	Δρ_min = −0.16 e Å⁻³

Crystal data top

C₂₂H₁₆O₄	V = 3429.5 (4) Å³
M_r = 344.35	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 21.2454 (15) Å	µ = 0.09 mm⁻¹
b = 13.2363 (7) Å	T = 296 K
c = 12.1954 (7) Å	0.27 × 0.22 × 0.08 mm

Data collection top

Bruker SMART APEXII DUO CCD diffractometer	5014 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	2961 reflections with I > 2σ(I)
T_min = 0.976, T_max = 0.993	R_int = 0.075
67362 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	0 restraints
wR(F²) = 0.113	H-atom parameters constrained
S = 0.99	Δρ_max = 0.16 e Å⁻³
5014 reflections	Δρ_min = −0.16 e Å⁻³
235 parameters

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2sigma(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.26894 (5)	0.00729 (8)	−0.06424 (9)	0.0525 (3)
O2	0.28774 (4)	0.14794 (8)	0.03621 (8)	0.0431 (2)
O3	0.18085 (5)	0.27892 (8)	−0.05404 (9)	0.0517 (3)
O4	0.25786 (5)	0.22593 (9)	−0.16930 (8)	0.0494 (3)
C1	0.07994 (7)	0.07069 (12)	0.06878 (12)	0.0481 (4)
H1A	0.0415	0.0732	0.0323	0.058*
C2	0.08085 (7)	0.06903 (14)	0.18225 (13)	0.0551 (4)
H2A	0.0432	0.0708	0.2211	0.066*
C3	0.13733 (8)	0.06473 (13)	0.23800 (13)	0.0525 (4)
H3A	0.1378	0.0628	0.3142	0.063*
C4	0.19297 (7)	0.06329 (12)	0.18020 (12)	0.0461 (4)
H4A	0.2311	0.0611	0.2177	0.055*
C5	0.19263 (6)	0.06515 (10)	0.06611 (11)	0.0375 (3)
C6	0.13535 (6)	0.06867 (11)	0.00836 (11)	0.0382 (3)
C7	0.13142 (6)	0.07071 (11)	−0.11413 (11)	0.0397 (3)
C8	0.09627 (7)	−0.00380 (13)	−0.16669 (14)	0.0492 (4)
H8A	0.0757	−0.0524	−0.1250	0.059*
C9	0.09149 (8)	−0.00670 (14)	−0.27979 (15)	0.0587 (5)
H9A	0.0677	−0.0569	−0.3134	0.070*
C10	0.12184 (8)	0.06460 (15)	−0.34267 (14)	0.0602 (5)
H10A	0.1185	0.0625	−0.4187	0.072*
C11	0.15715 (7)	0.13905 (14)	−0.29305 (12)	0.0511 (4)
H11A	0.1781	0.1866	−0.3357	0.061*
C12	0.16148 (6)	0.14330 (11)	−0.17924 (11)	0.0404 (3)
C13	0.19893 (7)	0.22471 (12)	−0.12604 (12)	0.0417 (3)
C14	0.30724 (7)	0.26949 (13)	−0.10300 (13)	0.0508 (4)
H14A	0.2900	0.3201	−0.0539	0.061*
H14B	0.3386	0.3014	−0.1493	0.061*
C15	0.33672 (6)	0.18389 (12)	−0.03764 (12)	0.0433 (3)
H15A	0.3492	0.1293	−0.0874	0.052*
C16	0.25324 (6)	0.06640 (11)	0.00485 (12)	0.0384 (3)
C17	0.39237 (6)	0.21678 (12)	0.02917 (12)	0.0446 (3)
C18	0.45246 (7)	0.18547 (15)	0.00219 (14)	0.0592 (4)
H18A	0.4587	0.1439	−0.0583	0.071*
C19	0.50365 (8)	0.21590 (18)	0.06533 (17)	0.0737 (6)
H19A	0.5441	0.1957	0.0460	0.088*
C20	0.49468 (9)	0.27522 (16)	0.15542 (18)	0.0722 (6)
H20A	0.5288	0.2936	0.1989	0.087*
C21	0.43562 (10)	0.30752 (16)	0.18154 (16)	0.0706 (5)
H21A	0.4298	0.3491	0.2422	0.085*
C22	0.38446 (8)	0.27928 (14)	0.11904 (14)	0.0584 (4)
H22A	0.3445	0.3024	0.1374	0.070*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0485 (6)	0.0438 (6)	0.0653 (7)	0.0023 (5)	0.0063 (5)	−0.0075 (5)
O2	0.0387 (5)	0.0468 (6)	0.0439 (5)	−0.0077 (4)	0.0023 (4)	0.0004 (5)
O3	0.0564 (6)	0.0452 (6)	0.0536 (6)	0.0025 (5)	−0.0006 (5)	−0.0029 (5)
O4	0.0434 (5)	0.0608 (7)	0.0440 (6)	−0.0064 (5)	−0.0021 (4)	0.0075 (5)
C1	0.0363 (7)	0.0583 (10)	0.0498 (9)	−0.0033 (7)	−0.0002 (6)	0.0030 (8)
C2	0.0455 (8)	0.0677 (12)	0.0521 (10)	−0.0073 (8)	0.0113 (7)	0.0018 (8)
C3	0.0584 (9)	0.0594 (10)	0.0398 (8)	−0.0107 (8)	0.0029 (7)	0.0032 (7)
C4	0.0472 (8)	0.0479 (9)	0.0432 (8)	−0.0070 (7)	−0.0058 (6)	0.0062 (7)
C5	0.0382 (7)	0.0333 (7)	0.0410 (7)	−0.0027 (6)	−0.0011 (6)	0.0038 (6)
C6	0.0365 (7)	0.0378 (7)	0.0405 (7)	−0.0013 (6)	−0.0019 (6)	0.0027 (6)
C7	0.0333 (6)	0.0443 (8)	0.0416 (7)	0.0052 (6)	−0.0023 (6)	−0.0020 (6)
C8	0.0420 (7)	0.0500 (9)	0.0557 (9)	0.0000 (7)	−0.0016 (7)	−0.0073 (8)
C9	0.0511 (9)	0.0685 (12)	0.0566 (10)	0.0000 (9)	−0.0052 (8)	−0.0228 (9)
C10	0.0563 (9)	0.0838 (14)	0.0405 (8)	0.0066 (10)	−0.0045 (7)	−0.0124 (9)
C11	0.0483 (8)	0.0649 (11)	0.0400 (8)	0.0051 (8)	−0.0009 (7)	0.0021 (8)
C12	0.0361 (6)	0.0463 (8)	0.0387 (7)	0.0056 (6)	−0.0028 (6)	0.0005 (6)
C13	0.0427 (7)	0.0434 (8)	0.0391 (7)	0.0019 (6)	−0.0035 (6)	0.0107 (7)
C14	0.0436 (8)	0.0549 (10)	0.0539 (9)	−0.0118 (7)	−0.0041 (7)	0.0081 (8)
C15	0.0376 (7)	0.0486 (8)	0.0437 (8)	−0.0068 (6)	0.0042 (6)	0.0024 (7)
C16	0.0365 (6)	0.0354 (7)	0.0433 (7)	0.0013 (6)	−0.0053 (6)	0.0055 (6)
C17	0.0389 (7)	0.0483 (9)	0.0467 (8)	−0.0072 (7)	0.0008 (6)	0.0089 (7)
C18	0.0435 (8)	0.0797 (13)	0.0544 (10)	−0.0010 (8)	0.0062 (7)	0.0063 (9)
C19	0.0367 (8)	0.1048 (17)	0.0796 (14)	−0.0100 (10)	0.0000 (9)	0.0220 (13)
C20	0.0571 (10)	0.0842 (14)	0.0752 (13)	−0.0311 (10)	−0.0176 (10)	0.0184 (11)
C21	0.0758 (12)	0.0676 (13)	0.0682 (12)	−0.0184 (10)	−0.0152 (10)	−0.0050 (10)
C22	0.0521 (9)	0.0604 (11)	0.0626 (11)	−0.0031 (8)	−0.0051 (8)	−0.0048 (9)

Geometric parameters (Å, º) top

O1—C16	1.1972 (17)	C9—H9A	0.9300
O2—C16	1.3596 (17)	C10—C11	1.378 (2)
O2—C15	1.4562 (16)	C10—H10A	0.9300
O3—C13	1.1973 (17)	C11—C12	1.392 (2)
O4—C13	1.3586 (17)	C11—H11A	0.9300
O4—C14	1.4446 (18)	C12—C13	1.488 (2)
C1—C2	1.384 (2)	C14—C15	1.520 (2)
C1—C6	1.3891 (19)	C14—H14A	0.9700
C1—H1A	0.9300	C14—H14B	0.9700
C2—C3	1.380 (2)	C15—C17	1.5003 (19)
C2—H2A	0.9300	C15—H15A	0.9800
C3—C4	1.376 (2)	C17—C18	1.382 (2)
C3—H3A	0.9300	C17—C22	1.383 (2)
C4—C5	1.3916 (19)	C18—C19	1.392 (2)
C4—H4A	0.9300	C18—H18A	0.9300
C5—C6	1.4068 (18)	C19—C20	1.364 (3)
C5—C16	1.4888 (19)	C19—H19A	0.9300
C6—C7	1.4965 (19)	C20—C21	1.363 (3)
C7—C8	1.393 (2)	C20—H20A	0.9300
C7—C12	1.400 (2)	C21—C22	1.379 (2)
C8—C9	1.384 (2)	C21—H21A	0.9300
C8—H8A	0.9300	C22—H22A	0.9300
C9—C10	1.376 (3)

C16—O2—C15	118.08 (11)	C7—C12—C13	119.56 (12)
C13—O4—C14	117.17 (12)	O3—C13—O4	124.98 (14)
C2—C1—C6	121.21 (14)	O3—C13—C12	125.60 (13)
C2—C1—H1A	119.4	O4—C13—C12	109.39 (13)
C6—C1—H1A	119.4	O4—C14—C15	107.18 (13)
C3—C2—C1	120.35 (14)	O4—C14—H14A	110.3
C3—C2—H2A	119.8	C15—C14—H14A	110.3
C1—C2—H2A	119.8	O4—C14—H14B	110.3
C4—C3—C2	119.66 (14)	C15—C14—H14B	110.3
C4—C3—H3A	120.2	H14A—C14—H14B	108.5
C2—C3—H3A	120.2	O2—C15—C17	108.79 (11)
C3—C4—C5	120.49 (14)	O2—C15—C14	105.86 (11)
C3—C4—H4A	119.8	C17—C15—C14	113.15 (13)
C5—C4—H4A	119.8	O2—C15—H15A	109.6
C4—C5—C6	120.37 (13)	C17—C15—H15A	109.6
C4—C5—C16	119.83 (12)	C14—C15—H15A	109.6
C6—C5—C16	119.77 (12)	O1—C16—O2	124.52 (13)
C1—C6—C5	117.92 (13)	O1—C16—C5	125.93 (13)
C1—C6—C7	118.80 (12)	O2—C16—C5	109.50 (12)
C5—C6—C7	123.27 (12)	C18—C17—C22	118.70 (15)
C8—C7—C12	117.99 (13)	C18—C17—C15	120.77 (15)
C8—C7—C6	118.44 (13)	C22—C17—C15	120.53 (14)
C12—C7—C6	123.57 (13)	C17—C18—C19	120.21 (18)
C9—C8—C7	121.17 (16)	C17—C18—H18A	119.9
C9—C8—H8A	119.4	C19—C18—H18A	119.9
C7—C8—H8A	119.4	C20—C19—C18	120.20 (18)
C10—C9—C8	120.13 (16)	C20—C19—H19A	119.9
C10—C9—H9A	119.9	C18—C19—H19A	119.9
C8—C9—H9A	119.9	C21—C20—C19	119.83 (17)
C9—C10—C11	120.04 (15)	C21—C20—H20A	120.1
C9—C10—H10A	120.0	C19—C20—H20A	120.1
C11—C10—H10A	120.0	C20—C21—C22	120.74 (19)
C10—C11—C12	120.17 (16)	C20—C21—H21A	119.6
C10—C11—H11A	119.9	C22—C21—H21A	119.6
C12—C11—H11A	119.9	C21—C22—C17	120.28 (17)
C11—C12—C7	120.49 (14)	C21—C22—H22A	119.9
C11—C12—C13	119.94 (14)	C17—C22—H22A	119.9

C6—C1—C2—C3	−0.4 (3)	C11—C12—C13—O3	129.03 (16)
C1—C2—C3—C4	0.8 (3)	C7—C12—C13—O3	−51.7 (2)
C2—C3—C4—C5	−0.6 (3)	C11—C12—C13—O4	−53.03 (17)
C3—C4—C5—C6	0.1 (2)	C7—C12—C13—O4	126.21 (13)
C3—C4—C5—C16	178.33 (15)	C13—O4—C14—C15	92.18 (15)
C2—C1—C6—C5	−0.2 (2)	C16—O2—C15—C17	−141.79 (12)
C2—C1—C6—C7	−179.94 (15)	C16—O2—C15—C14	96.32 (14)
C4—C5—C6—C1	0.3 (2)	O4—C14—C15—O2	−65.31 (15)
C16—C5—C6—C1	−177.94 (14)	O4—C14—C15—C17	175.64 (12)
C4—C5—C6—C7	−179.93 (14)	C15—O2—C16—O1	18.96 (19)
C16—C5—C6—C7	1.8 (2)	C15—O2—C16—C5	−158.71 (11)
C1—C6—C7—C8	−56.42 (19)	C4—C5—C16—O1	124.59 (16)
C5—C6—C7—C8	123.83 (15)	C6—C5—C16—O1	−57.1 (2)
C1—C6—C7—C12	123.92 (16)	C4—C5—C16—O2	−57.78 (17)
C5—C6—C7—C12	−55.8 (2)	C6—C5—C16—O2	120.49 (14)
C12—C7—C8—C9	0.5 (2)	O2—C15—C17—C18	132.03 (15)
C6—C7—C8—C9	−179.19 (14)	C14—C15—C17—C18	−110.62 (17)
C7—C8—C9—C10	0.2 (3)	O2—C15—C17—C22	−48.06 (19)
C8—C9—C10—C11	0.1 (3)	C14—C15—C17—C22	69.29 (19)
C9—C10—C11—C12	−1.0 (2)	C22—C17—C18—C19	0.6 (3)
C10—C11—C12—C7	1.6 (2)	C15—C17—C18—C19	−179.52 (16)
C10—C11—C12—C13	−179.13 (14)	C17—C18—C19—C20	1.3 (3)
C8—C7—C12—C11	−1.4 (2)	C18—C19—C20—C21	−2.2 (3)
C6—C7—C12—C11	178.28 (13)	C19—C20—C21—C22	1.3 (3)
C8—C7—C12—C13	179.39 (13)	C20—C21—C22—C17	0.6 (3)
C6—C7—C12—C13	−1.0 (2)	C18—C17—C22—C21	−1.5 (3)
C14—O4—C13—O3	21.5 (2)	C15—C17—C22—C21	178.61 (16)
C14—O4—C13—C12	−156.50 (12)

Experimental details

Crystal data
Chemical formula	C₂₂H₁₆O₄
M_r	344.35
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	296
a, b, c (Å)	21.2454 (15), 13.2363 (7), 12.1954 (7)
V (Å³)	3429.5 (4)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.27 × 0.22 × 0.08

Data collection
Diffractometer	Bruker SMART APEXII DUO CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.976, 0.993
No. of measured, independent and observed [I > 2σ(I)] reflections	67362, 5014, 2961
R_int	0.075
(sin θ/λ)_max (Å⁻¹)	0.704

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.113, 0.99
No. of reflections	5014
No. of parameters	235
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.16, −0.16

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Footnotes

‡Thomson Reuters ResearcherID: A-3561-2009.

§Thomson Reuters ResearcherID: A-5525-2009.

Acknowledgements

HKF and CKQ thank Universiti Sains Malaysia for the Research University Grant (No. 1001/PFIZIK/811160). Financial support from the National Natural Science Foundation of China (20972067) is acknowledged.

References

Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Fun, H.-K., Quah, C. K. & Wu, D. (2012). Acta Cryst. E68, accepted [IS5123]. CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wu, D., Wang, L., Xu, K., Song, J., Fun, H-K., Xu, J. & Zhang, Y. (2012). Chem. Commun. 48, 1168–1170. Web of Science CSD CrossRef CAS Google Scholar