(E nar structure owing to CABr p halogen bonds. a b s t r a c t thiazine rings increases in their excited state . According to
Cambridge Structural Database (CSD) , 26 structures of planar phenothiazines have been reported, including those of 22 charged phenothiazines. In the remaining four compounds [18–20], they have no charges on phenothiazine rings, and the reason for planarity was interpreted as stabilization by intramolecular charge transfer interaction. ical Co., L on of 10-(p ccording literature [21,22]. H and C NMR spectra were recorded on
JNM-ECA-400 spectrometer in chloroform-d with tetrame ane as an internal standard. All 13C NMR spectra were ob with a complete proton decoupling. Elemental analysis was performed on a J-SCEINCE LAB MICRO CORDER JM10.
Single crystal XRD
X-ray crystallographic data were collected at 180 C on a RIGAKU Saturn 724 + CCD device with using multi-layered mirror ⇑ Corresponding author.
E-mail address: firstname.lastname@example.org (T. Okuno).
Journal of Molecular Structure 1084 (2015) 172–176
Contents lists availab ec lsebeen paid to correlation between their properties and structures.
Generally, phenothiazines are known to have a butterfly structure. In contrast, they have a planar structure when they have positive charges. A recent report also indicated planarity of phenoAll chemicals were purchased from Kanto Chem were used without further purification. Preparati yn-1-yl)-10H-phenothiazine was carried out a 1 13http://dx.doi.org/10.1016/j.molstruc.2014.11.066 0022-2860/ 2014 Elsevier B.V. All rights reserved.td. and rop-1to the a JEOL thylsiltainedIntroduction
Phenothiazines, which are classified into an important class of tricyclic nitrogen–sulfur heterocycles [1,2], are known to have good electron donating property, and have been used to make charge transfer complexes [3–12]. Phenothiazines also attracted interest from the viewpoints of photoinduced electron transfer (PET)  or pharmacology [14,15]. Hence much attention has
We wish to report herein the fifth anomalous planar phenothiazine compound, (E)-10-(1,2-dibromoprop-1-en-1-yl)-10Hphenothiazine, which was obtained by bromine addition to 10-(prop-1-yn-1-yl)-10H-phenothiazine.
Halogen bond The E isomer shows an anomalous pla a r t i c l e i n f o
Received 28 October 2014
Received in revised form 26 November 2014
Accepted 26 November 2014
Available online 17 December 2014
YnaminesBoth Z and E isomers of 10-(1,2-dibromoprop-1-en-1-yl)-10H-phenothiazine were given by bromine addition to 10-(prop-1-yn-1-yl)-10H-phenothiazine with little stereoselectivity. The crystal structure of the Z isomer showed a usual butterfly structure, while that of the E isomer afforded an anomalous planar structure which was usually observed in positively charged phenothiazines. The reason for the planar structure was concluded to originate in intermolecular charge transfer interaction through the CABr p halogen bonds. 2014 Elsevier B.V. All rights reserved. Bromine addition to 10-propynylphenothiazine proceeds without stereoselectivity. Crystal structures of E and Z isomers are discussed based on DFT calculations.Anomalous planar structure observed in 1-yl)-10H-phenothiazine
Satoru Umezono, Tsunehisa Okuno ⇑
Department of Material Science and Chemistry, Wakayama University, Japan h i g h l i g h t s
Journal of Mol journal homepage: www.e)-10-(1,2-dibromoprop-1-enle at ScienceDirect ular Structure vier .com/locate /molstruc calculations were set at those obtained by single crystal XRD or by for C15H11N1O1S1Br2: C, 45.37; H, 2.79; N, 3.53. Found; C, 45.15; H, 1-yl)-10H-phenothiazine in benzene gave both Z and E isomers
Crystal structures of the Z and E isomers
Single crystals of the Z and E isomers with sufficient quality for
X-ray analysis were obtained by slow concentration from toluene solutions. Crystal data and geometric parameters of both isomers are summarized at Tables 1 and 2, respectively.
Fig. 1 shows the crystal structure of the Z isomer. In the Z isomer, the phenothiazine moiety has a butterfly structure, and the central six-membered ring has a boat conformation. The dihedral angle between two benzene rings is 31.11(14). The structure around the nitrogen atom is pyramidal, where the N atom locates upward at 0.128(3) Å from the plane formed by three adjacent carbon atoms (plane N). The dihedral angle between plane N and
N1/C13/C14/C15/Br1/Br2 (r.m.s. deviation = 0.0206 Å) is 87.88(3), indicating the phenothiazine moiety does not conjugate with the dibromopropenyl group. Intramolecular contact can be detected at Csp3AH N1 and Br1 H11 where the distances are 2.480(5) Å and 2.7759(9) Å, respectively.
Scheme 1. A result of bromine addition to 10-(prop-1-yn-1-yl)-10Hphenothiazine. h range () 2.1–31.3 2.0–31.2
Index ranges 24 6 h 6 23 13 6 h 6 13 15 6 k 6 13 11 6 k 6 13 17 6 l 6 17 15 6 l 6 16
Reflections collected 11,219 11,130
Independent reflections 3232 3170
I > 2r(I) 2926 2618
R (int) 0.024 0.025
Refinement method Full-matrix least-squares on
Goodness-of-fit on F2 1.126 0.989
R1, wR2 0.0395, 0.0901 0.0331, 0.0912
Refined parameters 173 190 lecular Structure 1084 (2015) 172–176 173as shown in Scheme 1. The configuration of both isomers was determined by single crystal XRD. (vide infra) The ratio of the Z and E isomers was estimated to be 40:60 judged by the integration of the NMR signals, but the isolated yields of both isomers are 24.9% and 13.6% respectively because of their instability for column chromatography.
This result indicates that the addition to the ynamine has little stereoselectivity as similar to previous reports , and suggests2.80; N, 3.51.
Results and discussion
Bromine addition to 10-(prop-1-yn-1-yl)-10H-phenothiazine
Bromine addition to an ynamine compound of 10-(prop-1-yn-calculations of RHF 6-31G(d) level.