Crystal Structure and Silver Ion Complexation of a Novel Porphyrazine Substituted with Four Dithiacrown Ether Rings

The synthesis of magnesium porphyrazines substituted with sulfur-containing 15-crown5 and 18-crown-6 macrocycles is reported as well as the single crystal structure of the 18-crown-6 substituted porphyrazine; the larger crown ether compound is shown to form dimers with Ag+ ions, unlike the porphyrazine with the smaller crown ether rings. Supramolecular structures from phthalocyanine and porphyrin building blocks are currently receiving great interest. As part of our program aimed at the develop­ ment of conducting materials^ from such structures, we describe here the first synthesis and metal ion binding properties of novel porphyrazines l(n) (n=l,2) substituted at the (3-positions with crown-ether rings. In addition, we present the first X-ray structure of a crowned porphyrin/phthalocyanine type of molecule. The crown ether precursors 2(1) and 2(2) were prepared from sodium d s l ,2-dicyano-l,2-ethylenedithiolate8 and tetraethyleneglycol-dichloride ( 11% yield) and pentaethyleneglycol-dichloride (23% yield), respectively, according to a slightly modified literature procedure.^ To a boiling suspension of 5 mmol magnesium in 10 mL npropanol was added a solution of 1 mmol of 2(n) in 10 mL rt-propanol and the reaction mixture was re fluxed for 18 h. The product was isolated and purified by washing with acetone and dry diethylether and subsequently by column chromatography (NaBr impregnated silica, eluent 2% MeOH in CHCI3 for 1( 1), and 10% MeOH in CHCI3 for 1(2)). Compounds 1(1) and 1(2) were obtained as dark blue 1(n) 2(n) powders in yields of 22% and 20%, respectively (m.p. > 320 °C).t Single crystals of 1(2) were grown from CHCl3/MeOH (1:1). X-ray data were collected on an Enraf-Nonius Cad4T/rotating anode diffractometer [MoKa (Mon); 150 K\. The compound crystallized in a triclinic unit cell, spacegroup PI, a = 9.584(3) A, b = 17.672(2) A, c = 19.620(4) A, a = 84.904(14)°, |J = 85.21(2)°, y = 89.29(2)°, V = 3298.3(13) A3, Z = 2. The structure was solved with SIR92 and refined using SHELXL92, resulting in R1 = 0.093, wR2 = 0.252, and S = 0.983. A PLUTON-plot is presented in Figure 1. The magnesium atom in the center of the porphyrazine is coordinated by one water molecule (probably from the solvent), which is linked with two bifurcated H-bonds to the crown ether ring of a neighboring porphyrazine. In this way a linear staircase-like structure is obtained. The nearest distance between the centers of two porphyrazine molecules amounts to 9.584(5) A. A detailed description of the structure will be published elsewhere.^ The binding affinities of compounds l(n) for silver(I) perchlorate were evaluated by UV/vis spectroscopy. On addition of an AgC104 solution to a solution of the 18crown-6 derivative 1(2) in 5% MeOH in CHCI3, the t The products were fully characterized by elemental analysis and s p e c t r o s c o p ic t e c h n iq u e s . C o m p o u n d 1(1): U V /v is ( C H C I 3 ) Xm a x /nm (log £): 675(4 .97) , 503(4 .07) , 378(4.89). 1H N M R (C D C I3 ): 5 3.31, 3.40, 3.89 (C H 2 O), 4.29 (C H 2 S). 13C N M R (C D C I3 ): 5 35 .02, 70.56, 140.01, 157.36. Anal, ealed for C4 g H 6 4 N g O i 2 S g M g (1225.9): C 47.03, H 5.26, N 9.14, S 20.92; found: C 47 .09 , H 5.34, N 9.04, S 20.36%. Compound 1(2): UV/vis (C H C I3 ) Xm a x /nm(log e): 675(4.97), 503(4.12), 377(4 .91) . 1H N M R (C D C I3 ): 5 3.32, 3.47, 3.85 ( C H 2 0 ) , 4.06 (C H 2 S). 13C N M R (C D C I3 ): 5 34.55, 70.24, 140.04, 157.22. Anal , ea led for C 5 g()N g O \ öS g M g (1402.1): C 47.97, H 5.75, N 7.99, S 18.29; found: C 48.03, H 5.80, N 7.99, S 18.09%.