Preparation, Spectral and Structural Characterization

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20 ml acetone and 4-methylquinoline (0.50 g, ... wise addition of 0.85 g (13 mmol) of NaN3 dis ... stand over several days to produce black crystals of 2. .... 100.0(1). N 1 -C u -N 2 3. 94.0(1). N 1- C u -C u A. 129.8(1). N 1- C u - N 11 A 160.1(1).
Preparation, Spectral and Structural Characterization of Two Polymeric 1:1 Mixed Ligand Complexes of Copper(II) Azide with 4-Methylquinoline and 2-Methylpyridine M ohamed A. S. G o h e r and Franz A. M autner*+ * + D epartm ent o f C hem istry, F aculty o f Science, A lex an d ria U niversity, A lexandria, Egypt ++ Institut für Physikalische und T heoretische C hem ie, Technische U niversität G raz, A -8010G raz, R ech b au erstraß e 12, A ustria Z. N aturforsch. 46b, 6 8 7 -6 9 2 (1991); received A u gust 28, 1990 C opper(II) Azide, C rystal S tructure, 4-M ethylquinoline, 2-M ethylpyridine, Spectroscopic Studies Two 1:1 mixed ligand com plexes o f co pper(II) azide w ith substituted quinoline an d pyri­ dine, namely catena d i-/i(l,l)-azid o -(4 -m eth y lq u in o lin e)co p p er(II) (1) and catena d i-//(l,3)azido-[di-//(l,l)-azido-bis(2-m ethylpyridine)dicopper(II)] (2) have been prepared and ch arac­ terized by X -ray crystallography. Crystal data: 1, C 10H 9N 7Cu, space group P 2 Jc, a = 577.8(2), b = 2202.3(5), c = 919.9(2) pm ,/? = 93.92(2)°, Z = 4, an d R = 0.035 fo r 1293 observed M o K « data; 2, C 6H 7N 7Cu, space group P 2 ,/a , a = 823.7(2), b = 1303.8(4), c = 895.3(3) p m ,/? = 112.23(2)°, Z = 4, and R = 0.022 for 2133 observed M o K a d iffracto m eter d a ta . In the stru ctu re o f 1, the C u(II) has a strongly distorted trigonal bypyram idal co o rd in atio n , w here b o th azido groups function as //(1,1) bridging ligands resulting in a co lu m n ar stru c tu re along the a axis. The polym eric com ­ plex 2 has a less d istorted square pyram idal structure; one h a lf o f the azide groups act as //(1,1) bridging ligands to form centrosym m etric dim ers. T hese dim eric units are fu rth er connected by the rem aining ,«(1,3) bridging azido groups to form layers w ithin the aA-plane. Infrared and electronic spectral d a ta are also presented and discussed.

Introduction

Experimental

Azide ligand binding to protein binuclear centres has played a key role in bioinorganic stud­ ies. This is because o f strong charge transfer ab­ sorption in the visible region, accessibility by IR and ESR spectroscopic techniques and its variable mode of bonding [1]. Terminal, end-on and endto-end bridging azido ligands are all known in cop­ per chemistry [2]. Recently we reported the syn­ thesis and structural characterizations of a series of copper azide complexes [3-6] in order to inves­ tigate the factors influencing the bonding modes of azide in these complexes. Now we have synthe­ sized two new 1:1 complexes of copper(II) azide with 4-methylquinoline (4-MeQ) and 2-methylpyridine (2-pic) and characterized them by X-ray crystallography, IR and reflectance spectra.

Preparation o f polymeric Cu( 4-M eQ ) (N 3) 2 (I)

* R eprint requests to D r. F. A. M autner. Verlag der Zeitschrift für N aturforschung, D-7400 Tübingen 0932 - 0776/91 /0500- 0687/$ 01.00/0

C u (N 0 3)3-3 H 20 (0.972 g, 4 mmol) dissolved in 20 ml acetone and 4-methylquinoline (0.50 g, 3.5 mmol) dissolved in 30 ml acetone were mixed together followed by the addition of N aN 3 (0.534 g, 8 mmol) dissolved in a minimum o f wa­ ter. The final mixture was boiled for several m in­ utes, cooled and allowed to stand until black wellformed crystals of 1 separated. C 10H 9N 7C u (290.8) Calcd C 41.32 H 3.12 N 33.70 Cu 21.85, Found C 41.08 H 3.41 N 33.52 Cu 21.80. Preparation o f polymeric Cu(2-pic) ( N3) 2 (2)

An ethanolic solution of 2-picoline (0.74 g, 8 mmol) was added to C u (N 0 3)2-3 H 20 (1.46 g, 6 mmol) dissolved in 40 ml ethanol. After dropwise addition of 0.85 g (13 mmol) of N aN 3 dis­ solved in 5 ml water to the stirred solution, the fin­ al mixture was heated and filtered. The filtrate was boiled for about 15 minutes, cooled and allowed to stand over several days to produce black crystals o f 2. C6H 7N 7Cu (240.7) Calcd C 29.95 H 2.93 N 40.73 Cu 26.39, Found C 29.78 H 3.02 N 40.61 Cu 26.22.

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M. A. S. G o h e r - F . A. M a u tn e r • Polym erie C u (4 -M cQ )(N 3); an d C u(2-pic)(N ,),

688

T able I. C rystallographic d ata.

C o m pound

1

2

Chem ical form ula F o rm u lar mass C rystal system Cell constants

C 10H 9N 7C u 290.8 m onoclinic a = 577.8(2) pm b = 2202.3(5) pm c = 919.9(2) pm ß = 93.92(2) V = 1167.8(6)x 106 pm 3

C 6H 7N 7C u 240.7 m onoclinic a = 823.7(2) pm h = 1303.8(4) pm c = 895.3(3) pm ß = 112.23(2) V = 890.0(5) x 106 pm 3 P 2 ,/a 4 484 1.796 M g /m 3 103(2) K 0.23x0.21 x 0.20 mm 2 0 < 64 hkl: - 1 2 ,0 ,0 /1 2 , 19,13 w -scan, A to = 1.4 2133 155 /;(M o K a ) = 2.43 m m ” 1 0.022 0.024 60.551