Complexes of Group 12 Metal Dihalides with 2-Acetylpyridine-N-oxide 4N-methylthiosemicarbazone...

Complexes of Group 12 Metal Dihalides with 2-Acetylpyridine-N-oxide4N-methylthiosemicarbazone (H4MLO). The Crystal Structures andOrganization of [Zn(H4MLO)X2] (X = Br, I)

Elena Bermejo, Alfonso CastinÄ eiras*, Ricardo DomõÂnguez

Santiago de Compostela/Spain, Universidad de Santiago de Compostela, Departamento de QuõÂmica InorgaÂnica

Rosa Carballo

Vigo/Spain, Universidad de Vigo, Departamento de QuõÂmica InorgaÂnica

CaÈcilia Maichle-MoÈ ssmer, Joachim StraÈhle

TuÈ bingen/Germany, Institut fuÈ r Anorganische Chemie der UniversitaÈ t

Anthony E. Liberta, Douglas X. West

Normal/USA, Illinois State University, Department of Chemistry

Received October 7th, 1999.

Abstract. Reaction of group 12 metal dihalides with 2-acetyl-pyridine-N-oxide 4N-methylthiosemicarbazone (H4MLO) inethanol afforded compounds [M(H4MLO)X2] (M = ZnII,CdII, HgII; X = Cl, Br, I), the structures of which were char-acterized by elemental analysis and by IR and 1H and13C NMR spectroscopy. In addition, the complexes of ZnBr2

and ZnI2 were analysed structurally by X-ray diffractometry.In [Zn(H4MLO)Br2] the ligand is O,N,S-tridentate and themetal is pentacoordinated, while in [Zn(H4MLO)I2] thethiosemicarbazone is S,O-bis-monodentate and the ZnII ca-

tion has a distorted tetrahedral coordination polyhedron.In assays of antifungal activity against Aspergillus nigerand Paecilomyces variotii, only the mercury compoundsshowed any activity, and only [Hg(H4MLO)Cl2] and[Hg(H4MLO)I2] were competitive with nystatin againstA. niger.

Keywords: Zinc complexes; Cadmium complexes; MercuryComplexes; Semicarbazones; Crystal structure

Komplexe von Metallhalogeniden der 12. Gruppe mit2-Acetylpyridin-N-oxid-4N-methylthiosemicarbazon (H4MLO).Kristallstrukturanalyse und Selbstassoziation von [Zn(H4MLO)X2] (X = Br, I)

InhaltsuÈ bersicht. Bei der Umsetzung von Zn-, Cd- und Hg-Halogeniden in Ethanol mit 2-Acetylpyridin-N-oxid-4N-me-thylthiosemicarbazon (H4MLO) erhaÈ lt man die Verbindun-gen [M(H4MLO)X2] (M = Zn, Cd, Hg; X = Cl, Br, I). DieCharakterisierung der Komplexe wurde mit Hilfe von Ele-mentaranalysen, 1H, 13C NMR- und von IR-Spektren durch-gefuÈ hrt. Die Strukturen der ZnBr2- und ZnI2-Verbindungenwurden mittels EinkristallroÈ ntgenstrukturanalyse bestimmt.In [Zn(H4MLO)Br2] zeigt der Ligand eine dreizaÈhnige

O,N,S-Koordination und das Metallatom hat die Koordinati-onszahl fuÈ nf, waÈhrend in [Zn(H4MLO)I2] zwei Thiosemicar-bazonliganden einzaÈhnig angreifen und das Zn-Kation einverzerrt tetraedrisches Koordinationspolyeder aufweist. Diefungizide AktivitaÈt gegen Aspergillus Niger und Paecilomy-ces Variotii wurde getestet, jedoch zeigten nur die Hg-Komplexen AktivitaÈ t und nur [Hg(H4MLO)Cl2] und[Hg(H4MLO)I2] waren wirksam gegen A. Niger.

Introduction

Heterocyclic thiosemicarbazones are simple but usefulsulphurated analogues of purine and pyrimidine bases[1, 2]. Both thiosemicarbazones and their complexeswith metals possess interesting biochemical and phar-

878 Ó WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000 0044±2313/00/626878±884 $ 17.50+.50/0 Z. Anorg. Allg. Chem. 2000, 626, 878±884

* Prof. Dr. A. CastinÄ eiras,Departamento de QuõÂmica InorgaÂnica,Facultad de Farmacia,Universidad de Santiago de Compostela,E-15706 Santiago de Compostela/Spain,Fax: + 3 49 81 54 71 63E-mail: [email protected]

Complexes of Group 12 Metal Dihalides with 2-Acetylpyridine-N-oxide 4N-methylthiosemicarbazone

macological properties [2]. So far, the coordination ofthiosemicarbazones with transition metals [2, 3] hasbeen more thoroughly explored than their coordina-tion with non-transition metals [4, 5]. As part of a pro-gramme aimed at correlating the structures of thiose-micarbazone complexes with their biological activity,we have synthesized and investigated the structuresand antifungal activities of complexes of group 12metals with the heterocyclic thiosemicarbazone2-acetylpyridine-N-oxide 4N-methylthiosemicarbazone(H4MLO). In this paper we report our findings.

Results and Discussion

Using the procedures described below, all the com-plexes of general formula [M(H4MLO)X2] (M = Zn,Cd or Hg; X = Cl, Br or I) were synthesized and iso-lated in good yield. All are yellow 1 : 1 adducts thatare stable in air, moderately soluble in common or-ganic solvents, and have melting points in the range182±322 °C.

Molecular Structures

Fig. 1 shows the molecular structure of [Zn(H4MLO)Br2]and Fig. 2 part of the polymeric structure of[Zn(H4MLO)I2]. Table 1 lists bond lengths and anglesin the coordination spheres of these compounds, andTable 2 presents analogous data for their thiosemicar-bazone moieties.

In [Zn(H4MLO)Br2], H4MLO is O,N,S-tridentateand the metal atom is pentacoordinated to the twobromine atoms and the O, S and azomethine N atomsof H4MLO. The s value [6] of 0.66 obtained takingb = N(2)±Zn(1)±Br(2) [165.09(10)°] and a = S(1)±Zn(1)±O(1) [125.49°] suggests that the complex canbe described as being about one third of the wayalong the path from a trigonal bipyramid (s = 1) to atetragonal pyramid (s = 0), whereas the reverse is thecase for other complexes of zinc halides with ligandscontaining a pyridine-N-oxide moiety [7]. In keepingwith this, the difference between the lengths of thetwo Zn±Br bonds, one of which is equatorial and theother axial in [Zn(H4MLO)Br2], is smaller than inthese other complexes [0.0448 AÊ , as against 0.114 and0.121 AÊ in the chloride and bromide derivatives,respectively], and the Zn±N(2) bond in[Zn(H4MLO)Br2], in which it is axial, is longer thanin [Zn(H4ELO)Cl2] or [Zn(H4ELO)Br2] (2.295(2) AÊ

as against 2.250(3) and 2.261(6) AÊ in the chloride and

bromide complexes, respectively [7]). For the samereason, Zn±N(2) is also longer than in complexes ofzinc with hydrazines [8] and Schiff bases [9]. Zn±S issomewhat longer than in other complexes of zinc withthiocarbonyl ligands [8], and Zn±O is shorter than inhexacoordinate zinc complexes involving pyridine-N-oxides [8]. As in other complexes between group 12halides and thiosemicarbazones with pyridine-N-oxidemoieties [7, 10], the ligand is non-planar (whereas it isplanar in the complexes of the corresponding unoxi-dized pyridine thiosemicarbazones [5, 7, 10±12]).

In [Zn(H4MLO)I2] (Fig. 2), H4MLO is O,S-bis-monodentate, bridging between ZnI2 units to form apolymeric structure (Fig. 3). Thus each zinc atom coor-dinates tetrahedrally to the two iodine atoms [at dis-tances of 2.5183(5) and 2.5558(5) AÊ ], the oxygen atomof one ligand [Zn(1)±O(1) = 2.073(1) AÊ ], and the sul-

Z. Anorg. Allg. Chem. 2000, 626, 878±884 879

Fig. 1 Structure of [Zn(H4MLO)Br2], showing the number-ing scheme and the coordination geometry about the zincatom. Thermal ellipsoids are drawn at 50% probability.

Table 1 Selected bond lengths/AÊ and angles/° in the com-plexes [Zn(H4MLO)Br2] and [Zn(H4MLO)I2]

[Zn(H4MLO)Br2] [Zn(H4MLO)I2]

Zn(1)±X(1) 2.4207(7) 2.5558(5)Zn(1)±X(2) 2.4655(8) 2.5183(5)Zn(1)±S(1) 2.3616(14) 2.3737(5)*Zn(1)±O(1) 2.017(3) 2.0727(13)Zn(1)±N(2) 2.295(3) ±

O(1)±Zn(1)±X(1) 109.20(9) 97.31(4)O(1)±Zn(1)±X(2) 94.59(9) 110.18(4)O(1)±Zn(1)±N(2) 76.05(12) ±N(2)±Zn(1)±X(1) 93.32(9) ±N(2)±Zn(1)±X(2) 165.09(10) ±X(1)±Zn(1)±X(2) 100.80(3) 126.446(13)S(1)±Zn(1)±X(1) 119.94(5) 111.734(17)*S(1)±Zn(1)±X(2) 97.85(4) 106.693(18)*S(1)±Zn(1)±O(1) 125.49(10) 101.43(4)*S(1)±Zn(1)±N(2) 78.94(9) ±

* Symmetry transformation used to generate equivalent atom S(1):1.0 ± x, 0.5 + y, 0.5 ± z

phur atom of another [Zn(1)±S(1) = 2.3737(5) AÊ ].These coordinate bonds are rather longer than mightbe expected for a tetrahedral ZnI2OS nucleus [8]. Inthe tetrahedral coordination polyhedron, greatest an-gular distortion is exhibited by O(1)±Zn(1)±I(1)[97.4(2)°] and I(1)±Zn(1)±I(2) [126.37(8)°]. The bondlengths and angles of the thiosemicarbazone moietydo not differ significantly from those found in themonomeric complex [Zn(H4MLO)Br2], but the anglebetween the least-squares planes of the thiosemicarba-

zone moiety and the pyridine-N-oxide ring is63.3(1)° in [Zn(H4MLO)I2] and only 18.8(2)° in[Zn(H4MLO)Br2].

Supramolecular association. The crystals of both[Zn(H4MLO)Br2] and [Zn(H4MLO)I2] exhibit supra-molecular organization [13]. In [Zn(H4MLO)Br2], hy-drogen bonds between Br(2) and the N(3) and N(4)atoms of a neighbouring molecule link the monomersin parallel coplanar strips on the ac face of the crystal(Fig. 4). Along the b axis, these layers are piled withthe strips of one layer rotated 180° with respect tothose of the next (¯¯¯ . . . ® b), the distance be-tween the ring planes of coparallel strips, 4.42 AÊ , pos-sibly being not too large for p-p interaction (for whichthe optimal distance is 3.60 AÊ [14]).

In [Zn(H4MLO)I2] polymeric chains along the baxis arise from the bridging behaviour of H4MLO, asnoted above. The helicoidal configuration of thesechains is somewhat reminiscent of ssDNA [15](Fig. 3). Hydrophobic strips exist both on the inside(due to the acetylpyridine methyls) and on the outside(due to the pyridine rings and the N(4) methyls). Eachhelix is reinforced internally by two series of hydrogenbonds (one between N(3) and the oxygen of the pre-ceding [Zn(H4MLO)I2] unit, the other between N(4)and I(1) of following [Zn(H4MLO)I2] unit; (see Ta-ble 3), but not by ring stacking interactions, the dis-tance between the pyridine ring planes being similarto the length of the unit cell in the b direction

E. Bermejo et al.

880 Z. Anorg. Allg. Chem. 2000, 626, 878±884

Table 2 Selected bond lengths/AÊ and angles/° in the thiose-micarbazone moiety of the complexes [Zn(H4MLO)Br2]and [Zn(H4MLO)I2]

[Zn(H4MLO)Br2] [Zn(H4MLO)I2]

O(1)±N(1) 1.334(5) 1.336(2)C(6)±N(2) 1.287(5) 1.310(2)N(2)±N(3) 1.367(5) 1.358(2)N(3)±C(7) 1.359(6) 1.362(2)C(7)±S(1) 1.687(4) 1.695(2)C(7)±N(4) 1.307(6) 1.305(2)

C(5)±N(1)±O(1) 123.4(3) 118.06(15)C(1)±N(1)±O(1) 115.8(4) 118.61(15)N(1)±C(5)±C(6) 120.5(4) 118.40(15)C(5)±C(6)±N(2) 118.0(3) 110.29(15)C(6)±N(2)±N(3) 118.7(3) 118.24(15)N(2)±N(3)±C(7) 119.6(4) 119.07(15)N(3)±C(7)±S(1) 122.9(3) 120.03(14)N(3)±C(7)±N(4) 114.8(4) 116.27(16)S(1)±C(7)±N(4) 122.3(4) 123.59(13)

Fig. 2 Part of the polymeric structure of [Zn(H4MLO)I2] showing the numbering scheme, the H4MLO ligand O,S-bridgingbetween ZnI2 units, and the coordination geometry about the zinc atoms. Thermal ellipsoids are drawn at 50% probability.


(8.395 A). Since the individual polymer chains are notlinked one to another either, the crystal is much lesscompact than that of [Zn(H4MLO)Br2].

The question arises as to the cause of the structuraldifferences between the bromide and iodide com-plexes. Although the softness of ZnII must dependsomewhat on the halide [16], this ought not to havestructural consequences; and in any case, the fact thatcomplexes of ZnBr2 and ZnI2 are generally isostruc-tural implies that in the present case the differencemust be mediated by the influence of the halide atomon the ligand. It is possible that the size of the halideatom may influence the conformation of the ligand, sofacilitating bridging behaviour in the case of the io-dide complex, but we know of no precedents amongcomplexes of ZnII halides with polydentate ligands.

Nor does it seem likely that the structural differenceswere due to crystallization conditions, since both com-pounds were recrystallized under the same conditions.It is possible that further studies may help clarify thisissue.

Infrared Spectra

The shift of m(C=N) to higher wavenumbers than inthe free ligand [17] cannot be taken as unequivocalevidence of coordination via the azomethine nitrogenbecause it occurs in all the complexes, including[Zn(H4MLO)I2], which the X-ray results show to becoordinated only through the S and O atoms; in thiscomplex, and possibly in others, the apparent shift ofm(C=N) to higher wavenumbers may be attributed toits overlapping the m(C=N) and m(C=C) bands of thepyridine ring. On the other hand, the shifts to lowerwave numbers of m(C=S) [i. e., thioamide band IV,which is largely from m(C=S)] may be taken to reflect

Z. Anorg. Allg. Chem. 2000, 626, 878±884 881

Fig. 3 Structure of the helicoidal polymeric chain of [Zn(H4MLO)I2] molecules along axis b.

Fig. 4 Unit cell of [Zn(H4MLO)Br2]; dashed lines indicatehydrogen bonds.

Table 3 Intermolecular hydrogen bonds in the compounds[Zn(H4MLO)Br2] and [Zn(H4MLO)I2]

D±H ´ ´ ´ A D±H (AÊ ) H ´ ´ ´ A (AÊ ) D ´ ´ A (AÊ) < (DHA)

[Zn(H4MLO)Br2]N(3)±H(3 A) ´ ´ ´ Br(2)i 0.82(5) 2.75(5) 3.494(4) 151(5)N(4)±H(40) ´ ´ ´ Br(2)i 0.68(4) 2.81(5) 3.468(5) 162(5)

[Zn(H4MLO)I2]N(3)±H(3) ´ ´ ´ O(1)ii 0.86 2.07 2.883(2) 158.4N(4)±H(4) ´ ´ ´ I(1)iii 0.86 2.92 3.660(2) 145.3

Symmetry transformations used to generate equivalent atoms:i = ±0.50 + x, 1.50 ± y, ±0.50 + z; ii = 1.00 ± x, ±0.50 + y, 0.50 ± z;iii = 1.00 ± x, 0.50 + y, 0.50 ± z

the coordination of all the complexes via the S atom,even though the expected m(M±S) bands are in mostcases indistinguishable because of overlapping withstronger m(M±N) bands between 330 and 340 cm±1

[18, 19]. O-coordination in all the complexes exceptpossibly the mercury compounds may likewise be in-ferred from the appearance of a m(M±O) band in therange 400±410 cm±1 and from the shifts of m(N±O) andd(N±O) to lower wavenumbers; the possibility that themercury compounds are not coordinated via the Oatom is suggested by the absence of any m(M±O)bands and would be in keeping with the behaviour ofmercury in its complexes with other pyridine-N-oxidethiosemicarbazones [10]. In most of the complexestwo bands due to m(M±X) vibrations also appear be-low 300 cm±1: the higher-frequency band is assigned tomas(M±X) and the lower-frequency band to ms(M±X).The frequency ratios m(M±Br)/m(M±Cl) = 0.72±0.73and m(M±I)/m(M±Cl) = 0.63±0.65 agree with values re-ported for other series of complexes between group 12metals and thiosemicarbazones [7, 10±12].

1H NMR Spectra

The 1H NMR signals of H4MLO and the complexeswere identified in accordance with published data[20]. The proton on N4 is deshielded in the Cd andHg complexes as the result of coordination via the sul-phur atom. The presence of a signal for N3H confirmsthe non-deprotonation of the ligand in the complexes,and in the Hg complexes its marked downfield shiftappears to reflect coordination via the azomethine ni-trogen. The downfield shifts of most of the pyridinering signals may reflect coordination via the oxygenatom, even though they are most pronounced in theHg complexes, in which the IR evidence suggests thatthere is no O-coordination.

13C NMR Spectra

The 13C NMR signals of H4MLO and the complexeswere identified in accordance with published data [20].The deshielding of C8 and C6 in the complexes suggeststhat in DMSO solution coordination via the sulphurand azomethine nitrogen is maintained. The markedshielding of C7 in the mercury complexes is similar tothat observed in other complexes of mercury with pyri-dine-N-oxide thiosemicarbazones [7, 11]. The downfieldshifts of the pyridine signals offer little information asto coordination to the metal via the ring.

Antifungal activity

Table 4 lists antifungal activity data for the mercurycomplexes, which were the only ones that showed anysuch activity. From the point of view of structure-ac-tivity correlation, it is of interest that all these activ-ities, like those of other complexes of 4N-monosubsti-

tuted pyridine-N-oxide thiosemicarbazones [7, 11], aregreater than those of complexes of group 12 metal ha-lides with the 4N-dimethylated analogue 2-acetylpyri-dine-N-oxide 4N-dimethylthiosemicarbazone [10].However, all the activities listed are less than those ofthe reference drug, nystatin, except those of certaindoses of the chloro and iodo complexes against Asper-gillus niger.

Experimental Section

General. All commercial reagents were Aldrich, Merck orVentron reagent-grade products and were used without priorpurification. Elemental analyses (C, N, H) were performedin a Carlo Erba 1108 microanalyser. Melting points weremeasured in a BuÈ chi melting point apparatus and are uncor-rected. IR spectra in KBr discs (4000±400 cm±1) or polyethy-lene-sandwiched Nujol mulls (500±100 cm±1) were recordedon a Mattson Instruments Cygnus 100 FTIR spectropho-tometer. 1H and 13C NMR spectra were recorded on aBruker WM-300 spectrometer; chemical shifts are reportedin d (parts per million) with TMS at 0.00 as internal refer-ence. The FAB mass spectrum of the ligand was obtained ona Kratos MS-50 instrument using m-nitrobenzyl alcohol asthe matrix.

Synthesis of 2-acetylpyridine-N-oxide 4N-methylthiosemicar-bazone. 2-Acetylpyridine-N-oxide was prepared as per Win-terfield and Zickel [21] by oxidation of 2-acetylpyridine withhydrogen peroxide. 2-Acetylpyridine-N-oxide 4N-methylthio-semicarbazone (H4MLO) was prepared using Klayman etal.'s [22] general method for condensation of amines with al-dehydes or ketones, as follows. A solution of 2-acetylpyri-dine-N-oxide (4.95 g, 0.036 mol) in 30 mL of ethanol wasslowly added to a solution of 4-methyl-3-thiosemicarbazide(3.80 g, 0.036 mol) in 75 mL of hot water. After refluxing for2 h, the product was filtered out and recrystallized fromethanol. Yield: 7.33 g (91%). Yellow, m.p. 189 °C.C9H12N4OS (224.14): calcd. C 48.2, H 5.4, N 25.0; foundC 48.6, H 5.2, N 25.5%.

IR (KBr) m(cm±1): 3310, 3187, 3065 (N±H), 1544 (C=N), 1256 (N±O), 839(C=S). 1H NMR (300 MHz, DMSO-d6) d(ppm): 2.23 (3 H, CCH3), 2.96(3 H, NCH3), 7.36/8.26 (4 H, Ar±H), 8.48 (1 H, N4H), 10.53 (1 H, N3H).13C NMR (300 MHz, DMSO-d6) d(ppm): 15.90 (CCH3), 31.02 (NCH3),125.20/127.05, 144.66±147.18 (Ar±C), 139.56 (C-py), 178.87 (C=S). FAB-MS m/z (%): 225(100) [L + H]+, 222(25.6) [L]+.

E. Bermejo et al.

882 Z. Anorg. Allg. Chem. 2000, 626, 878±884

Table 4 Antifungal activity data (growth inhibition zonediameters)

Concentration (lg ´ mL±1) 200 400 600 1000

Aspergillus niger[Hg(H4MLO)Cl2] 9.8 11.3 10.8 14.8[Hg(H4MLO)Br2] 6.0a 6.0 6.0 14.0[Hg(H4MLO)I2] 8.5 11.3 13.3 15.3nystatinb 9.0 10.7 12.8 17.3

Paecilomyces variotii[Hg(H4MLO)Cl2] 6.0 9.8 11.5 11.0[Hg(H4MLO)Br2] 7.0 10.9 15.1 16.9[Hg(H4MLO)I2] 9.8 13.3 15.8 13.7nystatinb 12.8 14.5 16.5 25.2

a 6.0 indicates no inhibition.b Commercially available therapeutic agent.


General Procedure for the Preparation of the complexes. Toa solution of H4MLO in hot ethanol was added an equimo-lar amount of the appropriate metal salt dissolved or sus-pended in ethanol. The mixture was stirred for about 1 week,and the yellowish solids formed were filtered out, washedwith ethanol and vacuum dried. Single crystals of[Zn(H4MLO)Br2] and [Zn(H4MLO)I2] were obtained byslow evaporation of solvent from the filtrate at room tem-perature.

[Zn(H4MLO)Cl2]. Yield: 270 mg (56%) Yellow, m. p. 247 °C.C9H12Cl2N4OSZn (360.43): calcd. C 30.0, H 3.4, N 15.5;found C 30.2, H 3.4, N 15.7%.

IR (KBr) m(cm±1): 3248, 3163, 3069 (N±H), 1588 (C=N), 1209 (N±O), 804(C=S). 1H NMR (300 MHz, DMSO-d6) d(ppm) 2.23 (3 H, CCH3), 2.95(3 H, NCH3), 7.45/8.25 (4 H, Ar±H), 8.47 (1 H, N4H), 10.53 (1 H, N3H).13C NMR (300 MHz, DMSO-d6) d(ppm): 16.26 (CCH3), 31.28 (NCH3),126.05/127.37, 144.89±147.25 (Ar±C), 139.86 (C-py), 178.95 (C=S).

[Zn(H4MLO)Br2]. Yield: 300 mg (45%). Yellow, m. p.332 °C. C9H12Br2N4OSZn (449.34): calcd. C 24.0, H 2.7,N 12.5; found C 24.2, H 2.6, N 12.5%.


[Zn(H4MLO)I2]. Yield: 620 mg (65%). Yellow, m. p. 230 °C.C9H12I2N4OSZn (543.33): calcd. C 19.9, H 2.2, N 10.3; foundC 20.1, H 2.1, N 10.4%.

IR (KBr) m(cm±1): 3254, 3220 sh, 3076 (N±H), 1588 (C=N), 1204 (N±O),822 (C=S). 1H NMR (300 MHz, DMSO-d6) d(ppm) 2.23 (3 H, CCH3),2.93 (3 H, NCH3), 7.47/8.28 (4 H, Ar±H), 8.47 (1 H, N4H), 10.63 (1 H,N3H). 13C NMR (300 MHz, DMSO-d6) d(ppm): 16.60 (CCH3), 31.44(NCH3), 126.83/127.56, 144.91±147.02 (Ar±C), 140.10 (C-py), 178.82(C=S).

[Cd(H4MLO)Cl2]. Yield: 310 mg (72%). Yellow, m. p.256 °C. C9H12CdCl2N4OS (407.45): calcd. C 26.5, H 3.0,N 13.8; found C 26.7, H 3.0, N 13.4%.


[Cd(H4MLO)Br2]. Yield: 330 mg (71%). Yellow, m. p.249 °C. C9H12Br2CdN4OS (496.37): calcd. C 21.8, H 2.4,N 11.3; found C 21.9, H 3.0, N 11.2%.

IR (KBr) m(cm±1): 3233, 3163, 3073 (N±H), 1586 (C=N), 1218 (N±O), 811(C=S). 1H NMR (300 MHz, DMSO-d6) d(ppm): 2.24 (3 H, CCH3), 2.95(3 H, NCH3), 7.41/8.24 (4 H, Ar±H), 8.51 (1 H, N4H), 10.52 (1 H, N3H).13C NMR (300 MHz, DMSO-d6) d(ppm): 16.35 (CCH3), 31.34 (NCH3),125.94/127.33, 145.31±147.24 (Ar±C), 139.87 (C-py), 178.55 (C=S).

[Cd(H4MLO)I2]. Yield: 370 mg (63%). Yellow, m. p. 214 °C.C9H12CdI2N4OS (590.35): calcd. C 18.3, H 2.1, N 9.5; foundC 18.5, H 2.0, N 9.4%.


[Hg(H4MLO)Cl2]. Yield: 330 mg (63%). Yellow, m. p. 182 °C(decomposition). C9H12Cl2HgN4OS (495.63): calcd. C 21.8,H 2.4, N 11.3; found C 22.0, H 2.3, N 11.3%.

IR (KBr) m(cm±1): 3268, 3128, 3077 (N±H), 1582 (C=N), 1227 (N±O).1H NMR (300 MHz, DMSO-d6) d(ppm): 2.38 (3 H, CCH3), 3.07 (3 H,NCH3), 7.44/8.30 (4 H, Ar±H), 9.40 (1 H, N4H), 10.10 (1 H, N3H).13C NMR (300 MHz, DMSO-d6) d(ppm): 17.29 (CCH3), 32.11 (NCH3),126.09/127.51, 146.37±151.86 (Ar±C), 139.88 (C-py), 172.32 (C=S).

[Hg(H4MLO)Br2]. Yield: 310 mg (57%). Yellow, m. p.189 °C. C9H12Br2HgN4OS (584.54): calcd. C 18.5, H 2.1,N 9.6; found C 18.7, H 1.9, N 9.6%.

IR (KBr) m(cm±1): 3221, 3071 (N±H), 1584 (C=N), 1205 (N±O), 801(C=S). 1H NMR (300 MHz, DMSO-d6) d(ppm): 2.36 (3 H, CCH3), 3.07(3 H, NCH3), 7.44/8.31 (4 H, Ar±H), 9.39 (1 H, N4H), 11.00 (1 H, N3H).13C NMR (300 MHz, DMSO-d6) d(ppm): 17.27 (CCH3), 32.23 (NCH3),126.16/127.53, 146.39±151.58 (Ar±C), 139.90 (C-py), 172.63 (C=S).

[Hg(H4MLO)I2]. Yield: 300 mg (56%). Yellow, m. p. 200 °C.C9H12I2HgN4OS (678.53): calcd. C 15.9, H 1.8, N 8.3; foundC 16.1, H 1.6, N 8.3%.


X-ray Crystallography. Crystals of [Zn(H4MLO)Br2] and[Zn(H4MLO)I2] that were suitable for X-ray diffractionwere mounted on glass fibres and transferred to an EnrafNonius CAD4 diffractometer. Accurate unit cell parametersand an orientation matrix were determined by least-squaresrefinement of the setting angles of a set of well-centred re-flections (SET4) [23] in the h ranges 8.469±13.700°([Zn(H4MLO)Br2]) and 11.432±28.719° ([Zn(H4MLO)I2]).Reduced cell calculations did not indicate higher lattice sym-metry [24]. Crystal data and details of data collection and re-finement are given in Table 5. The data were corrected forLp effects and for the observed linear decay of the reference

Z. Anorg. Allg. Chem. 2000, 626, 878±884 883

Table 5 Crystal and structure refinement data for com-pounds 2 and 3

Compound [Zn(H4MLO)Br2] [Zn(H4MLO)I2]

Empirical formula C9H12Br2N4OSZn C9H12I2N4OSZnFormula weight 449.48 543.46Wavelength/AÊ 0.71073 1.54056Crystal size/mm 0.35 ´ 0.15 ´ 0.10 0.35 ´ 0.10 ´ 0.05Crystal shape prism plateCrystal system monoclinic monoclinicSpace group P21/n (No. 14) P21/c (No. 14)a/AÊ 13.094(3) 9.818(2)b/AÊ 8.8385(7) 8.3947(5)c/AÊ 14.045(3) 20.654(4)b/° 112.927(10) 94.886(9)V/AÊ 3 1497.0(5) 1696.0(5)Z, Dcalcd./(Mg/m3) 4, 1.994 4, 2.128F(000) 872 1016h range/° 3.15±29.93 4.29±87.42Temperature/K 293(2) 293(2)hmin/hmax 0/18 ±12/12kmin/kmax 0/12 0/10lmin/lmax ±19/18 0/26l [mm±1] 7.111 31.714Max./min. transmissions 0.527/0.190 0.956/0.628Refl. collected/unique 4510/4341

(Rint = 0.038)3878/3878(Rint = 0.038)

Data/parameters 4341/211 3878/165Final R 0.041 0.052Final wR2 0.081 0.054GOF 0.976 1.057Max. Dq/(eA±3) 0.515 0.263

reflections. A semi-empirical absorption correction (w-scans[25]) was also applied. The structures were solved by directmethods and subsequent difference Fourier techniques(SHELXS) [26] and refined on F2 using SHELXL97 [27]([Zn(H4MLO)Br2]) or on F using SDP/VAX [28]([Zn(H4MLO)I2]). Hydrogen atoms were located in differ-ence Fourier maps and refined isotropically([Zn(H4MLO)Br2]) or were included in the refinement incalculated positions riding on their carrier atoms([Zn(H4MLO)I2]). Neutral atom scattering factors andanomalous dispersion corrections were taken from Interna-tional Tables for X-ray Crystallography [29]. Geometricalcalculations and illustrations were performed or generatedwith the SHELXL97 [27], PLATON98 [30] and SCHA-KAL98 [31] packages. Crystallographic data for the struc-tures reported in this paper (excluding structure factors)have been deposited with the Cambridge CrystallographicData Centre as supplementary publications CCDC-127815and CCDC-127816. Copies of the data can be obtained freeof charge on application to CCDC, 12 Union Road, Cam-bridge CB2 1EZ, UK (Fax, + 44-12 23/3 36-0 33; E-mail,[email protected]).

References

[1] E. S. Raper, Coord. Chem. Rev. 1996, 153, 199.[2] D. X. West, S. B. Padhye, P. B. Sonawane, Struct. Bond-

ing [Berlin] 1991, 76, 4.[3] [3 a] M. J. M. Campbell, Coord. Chem. Rev. 1975, 15,

279. ± [3 b] S. Padhye, G. B. Kauffman, Coord. Chem.Rev. 1985, 63, 127. ± [3 c] D. X. West, A. E. Liberta,S. B. Padhye, R. C. Chilate, P. B. Sonawane, A. S. Kumb-har, R. G. Yerande, Coord. Chem. Rev. 1993, 123, 49. ±[3 d] M. C. RodrõÂguez-ArguÈ elles, M. B. Ferrari, G. G. Fa-va, C. Pelizzi, P. Tarrasconi, R. Albetini, P. P. Dall'Aglio,P. Lunghi, S. Pinelli, J. Inorg. Biochem. 1995, 58, 157. ±[3 e] J. S. Casas, M. S. GarcõÂa-Tasende, C. Maiche-MoÈ ss-mer, M. C. RodrõÂguez-ArguÈ elles, A. SaÂnchez, J. Sordo,A. VaÂzquez-LoÂ pez, S. Pinelli, P. Lunghi, R. Albertini, J.Inorg. Biochem. 1996, 62, 41. ± [3 f] D. Kovala-Demert-zi, A. Domopoulou, M. A. Demertzis, J. ValdeÂs-MartõÂ-nez, S. HernaÂndez-Ortega, G. Espinosa-PeÂrez, D. X.West, M. M. Salberg, G. A. Bain, P. D. Bloom, Polyhe-dron 1996, 15, 2587. ± [3 g] R. Alonso, E. Bermejo,A. CastinÄ eiras, T. PeÂrez, R. Carballo, Z. Anorg. Allg.Chem. 1997, 623, 818.

[4] [4 a] C. E. Holloway, M. J. Melnik, J. Organomet. Chem.1995, 495, 1. ± [4 b] J. S. Casas, M. V. CastanÄ o, M. C. Ar-guÈ elles, A. SaÂnchez, J. Sordo, J. Chem. Soc., DaltonTrans. 1993, 1253. ± [4 c] J. S. Casas, E. E. Castellano,A. MacõÂas, M. C. ArguÈ elles, A. SaÂnchez, J. Sordo, J.Chem. Soc., Dalton Trans. 1993, 755.

[5] J. S. Casas, M. V. CastanÄ o, M. S. GarcõÂa-Tasende, I. Mar-tõÂnez-Santamarta, J. Sordo, E. E. Castellano, J. Zuker-man-Schpector, J. Chem. Res. 1992, 324.

[6] A. W. Addison, T. N. Rao, J. Reedijk, J. van Rijn, G. C.Verschoor, J. Chem. Soc., Dalton Trans. 1984, 1349.

[7] E. Bermejo, R. Carballo, A. CastinÄ eiras, R. DomõÂnguez,C. Maichle-MoÈ ssmer, J. StraÈhle, D. X. West, Eur. J. In-org. Chem. 1999 (Submitted).

[8] A. G. Orpen, L. Brammer, F. H. Allen, O. Kennard,D. G. Watson, R. Taylor, J. Chem. Soc., Dalton Trans.1989, 51.

[9] E. Labisbal, J. Romero, A. De Blas, J. A. GarcõÂa-VaÂz-quez, M. L. DuraÂn, A. CastinÄ eiras, A. Sousa, D. E. Fen-ton, Polyhedron 1992, 11, 53.

[10] E. Bermejo, R. Carballo, A. CastinÄ eiras, R. DomõÂnguez,A. E. Liberta, C. Maichle-MoÈ ssmer, D. X. West, Z. Nat-urforsch. 1999 (in press).

[11] E. Bermejo, A. CastinÄ eiras, R. DomõÂnguez, R. Carballo,C. Maichle-MoÈ ssmer, D. X. West, Z. Anorg. Allg. Chem.1999, 625, 961.

[12] E. Bermejo, R. Carballo, A. CastinÄ eiras, R. DomõÂnguez,A. E. Liberta, C. Maichle-MoÈ ssmer, M. M. Salberg,D. X. West, Eur. J. Inorg. Chem. 1999, 965.

[13] J. M. Lehn, Supramolecular Chemistry, VCH, Wein-heim, 1995.

[14] M. L. GloÂ wka, D. Martynowski, K. Kozlowska, J. Mol.Struc. 1999, 474, 81.

[15] R. C. Bohinski, Modern Concepts in Biochemistry,2nd ed., Allyn. and Bacon Inc., Boston, 1976.

[16] R. G. Pearson, Hard and Soft Acids and Bases, Dowden,Hutchinson & Roos, Inc. 1973.

[17] D. X. West, R. M. Makeever, G. Ertem, J. P. Scovill,L. K. Pannell, Transition Met. Chem. 1986, 11, 131.

[18] K. Nakamoto, Infrared and Raman Spectra of Inorganicand Coordination Compounds, 4th ed., Wiley, NewYork, 1986.

[19] J. Weidlein, U. MuÈ ller, K. Dehnicke, Schwingungsfre-quenzen II, G. Thieme Verlag, Stuttgart, 1986.

[20] [20 a] A. Ault, M. R. Ault, A Handy and Systematic Cat-alog of NMR Spectra, University Science Books, MillValley, 1980. ± [20 b] H. Mittese, H. Messer, B. Zech,Spektroskopische Methoden in der Organischen Chemie,4th ed.

[21] K. Winterfeld, W. Zickel, Arch. Pharm. (Weinheim,Ger.), 1969, 302, 900. Georg Thieme Verlag, Stuttgart,1991.

[22] [22 a] D. L. Klayman, J. F. Bartosevich, T. S. Griffin,C. J. Mason, J. P. Scovill, J. Med. Chem. 1979, 22, 855. ±[22 b] D. L. Klayman, J. P. Scovill, J. F. Bartosevich, C. J.Mason, J. Med. Chem. 1979, 22, 1367. ± [22 c] J. P. Sco-vill, D. L. Klayman, C. F. Franchino, J. Med. Chem.1982, 25, 1261. ± [22 d] D. L. Klayman, J. P. Scovill, J. FBartosevich, J. Bruce, J. Med. Chem. 1983, 26, 35. ±[22 e] J. P. Scovill, D. L. Klayman, C. Lambross, G. E.Childs, J. D. Notsch, J. Med. Chem. 1984, 27, 87.

[23] J. L. de Boer, A. J. M. Duisenberg, Acta Crystallogr.1984, A 40, 410.

[24] A. L. Spek, J. Appl. Crystallogr. 1988, 21, 578.[25] A. C. T. North, D. C. Phillips, F. S. Mathews, Acta Crys-

tallogr. 1968, A 24, 351.[26] G. M. Sheldrick, Acta Crystallogr. 1990, A 46, 467.[27] G. M. Sheldrick, SHELXL97, UniversitaÈ t GoÈ ttingen,

1997.[28] B. A. Frenz and Associates Inc. & Enraf-Nonius, SDP/

VAX Structure Determination Package, V. 2.2, CollegeStation, Texas, USA, 1986.

[29] A. J. C. Wilson, International Tables for Crystallography,vol. C, Kluwer Academic Publishers, Dordrecht, TheNetherlands, 1992.

[30] A. L. Spek, PLATON98, University of Utrecht, 1998.[31] E. Keller, SCHAKAL97, University of Freiburg i. Br.,

1997.

E. Bermejo et al.

884 Z. Anorg. Allg. Chem. 2000, 626, 878±884

Complexes of Group 12 Metal Dihalides with 2-Acetylpyridine-N-oxide 4N-methylthiosemicarbazone...

Documents

Transcript of Complexes of Group 12 Metal Dihalides with 2-Acetylpyridine-N-oxide 4N-methylthiosemicarbazone...