Nickel(II) and copper(II) complexes of mixed benzene-triazolehemiporphyrazines

Inorganica Chimica Acta 230 (1995) 153-157

ELSEVIER

Note

Nickel(II) and copper(II) complexes of mixed benzene-triazolehemiporphyrazines Salom6 Rodriguez-Morgade, Tomfis Torres * Departamento de Quimica (C-l), Facultad de Ciencias, Universidad Aut6noma de Madrid, 28049 Madrid, Spain Received 19 April 1994; revised 30 May 1994

Abstract

Condensation of 3,5-bis(3'-imino-l'-isoindolinylideneamino)-l,2,4-triazole with 1,3-diaminobenzene or 1,3-bis(3'-imino-l'isoindolinylideneamino)benzene with 3,5-diamine-l,2,4-triazole afforded the cross-conjugated mixed benzene-triazolehemiporphyrazine (2) together with variable amounts of the symmetrical macrocycles. Metallation of 2 with copper and nickel bromide gave the corresponding metal complexes 3. An alternative route for the preparation of 3--reaction of the three-unit metal complexes with 1,3-diaminobenzene--was attempted. All the new compounds were identified by fast atom beam mass spectrometry (FAB MS) and elemental analysis. Macrocycle 2 and its metal complexes 3 showed electrical conductivity in the range of the isolators (<10 -12 S cm-1). Keywords: Nickel complexes; Copper complexes; Porphyrazine complexes; Triazolehemiporphyrazines

1. Introduction

Recent investigations in this laboratory have led to the synthesis of hemiporphyrazine analogues with 1,2,4triazole moieties la and lb (M = H2, Mn, Fe, Co, Ni, Cu) [1-3]. These compounds are formal derivatives of phthalocyanines (Pc) [4] by replacement of two faceto-face isoindole rings either by two 1,2,4-triazole subunits or by 1,2,4-triazole and one pyridine moieties; they were prepared in connection with our studies on physical and spectroscopic properties of azaporphyrinic systems [2,3] and related compounds [5]. Our interest in the field is also directed toward the preparation of molecular chromophores related to phthalocyanines [4] having conjugated connecting pathways able to facilitate intramolecular charge-transfer transitions and, in turn, second-order nonlinear optical (NLO) responses [6]. Thus, we have recently described the preparation of asymmetric metallotriazolephthalocyanines [7] and soluble metallotriazolehemiporphyrazines derived from la [2], which are promising targets for second and third * Corresponding author.

0020-1693/95/$09.50 © 1995 Elsevier Science S.A. All rights reserved SSDI 0 0 2 0 - 1 6 9 3 ( 9 4 ) 0 4 2 9 2 - 4

harmonic generation (SHG and THG), respectively [8,9]. N--NH

/ .).. N"~N

N

N--M--N v

//

\\

N\

v

/N X I

/ N-NH " " \ a) X= ~/N//~,.

/ ~ b) X=

As an extension of this work, we decided to prepare the hemiporphyrazine derivative 2 with a benzene subunit. Compound 2 and two of its metal complexes 3 ( M = C o , Fe) have recently been obtained by other authors [10] by reaction of the three-unit compounds 3,5-bis(3'-imino-l'-isoindolinylideneamino)-l,2,4-triazole (4a) and 1,3-bis(3'-imino-l'-isoindolinylideneamino)benzene (4h) with 1,3-diaminobenzene and 3,5diamino-l,2,4-triazole, respectively, and subsequent metaUation. In this paper a revision of the syntheses of

S. Rodtiguez-Morgade,

154

T. Torres / Inorganica Chimica Acta 230 (1995) 153-157

2 and 3, as well as some aspects of the chemistry of 4a and 4b and some of their metal complexes, are reported. N-NH

H

N-NH

H

N--M--N v

2

//

\,

v

3a M =Cu(II) M :Ni(ll)

3b

2. Results and discussion

A detailed examination of the studies of Sokolov et al. [10] revealed the lack of relevant characterization data other than IR and UV-Vis spectra. The analytical data for the free ligand 2 are not in good agreement with the proposed structure. We suggest that the reported compound was not homogeneous, probably owing to important impurities of the macrocycles 5a and 5h, which are obtained together with 2 in the two reactions described; these compounds are difficult to distinguish using the techniques mentioned. N/

NH

N/ NH

X \N

HN

X ~NH2

N/

X ~N

N~

/N X~

i?o

N-NH a) X= ~ , N / ~ . b) X: c) X=

It is well known that 1,3-diiminoisoindoline and its derivatives react with aromatic diamines to afford either the linear three-unit compound 4 [3,11,12] or the corresponding hemiporphyrazine 5 [1,11-14] as a function of the stoichiometry of the reactants and the reaction conditions. Such a process goes through a series of steps that involve nucleophilic attack of the amino groups on iminic double bonds with elimination of ammonia. The yields of hemiporphyrazine derivatives are generally good. However, the employment of the same strategy to introduce two different aromatic moieties face-to-face in the structure by reaction of isolated three-unit intermediates 4 with a new aromatic diamine is not a trivial matter, although often reported in the literature [3,11,15]. In our hands the reaction of the

triazole derivative 4a with 1,3-diaminobenzene in 2ethoxyethanol at reflux temperature gave a mixture of the macrocycles 2, 5a and 5b in 26%, 36% and 23% yield, respectively. These results could be explained by taking into account three different reaction pathways which should act at the same time. The diamine would react with the two 'outer' iminic double bonds of 4a to give the expected compound 2. On the other hand, in competition with this macrocyclization reaction, the 1,3-diaminobenzene would also react with one of the 'inner' C = N bonds of 4a to yield the two-unit derivatives 6a and 6b. Self-condensation of both compounds would lead to a mixture of 2, 5a and 5b. The splitting of related three-unit compounds by means of amines is well documented [11,16]. Finally, compound 4a undergoes thermal cleavage, probably to give the two-unit compound 6a, which would dimerize to yield 5a. This last point was confirmed by heating 4a under the same reaction conditions in the absence of diamine. In this case compound 5a was obtained in 30% yield. In the same way, when the three-unit benzene derivative 4b [17] was reacted with 3,5-diamino-l,2,4triazole under similar reaction conditions, a mixture of the macrocycles 2, 5a and 5b was again obtained, now in 37%, 29% and 23% yield, respectively. In this case also, the three reaction pathways mentioned above should operate simultaneously. Paradoxically, the reaction of 1,3-diiminoisoindoline, 3,5-diamino-l,2,4-triazole (guanazole) and 1,3-diaminobenzene in a 2:1:1 molar ratio afforded a better yield of the mixed macrocycle 2 (42%). In this case the symmetrical compounds 5a and 5b were obtained in 17% and 23% yield, respectively. The different solubilities of the macrocycles allowed their separation by extraction methods. Compound 2 was characterized by 1H and 13C NMR, UV-Vis and IR spectroscopy, accurate mass spectra (electron impact) measurements and elemental analysis. The metal complexes 3a,b were obtained by treatment of 2 with the corresponding metal(II) bromide in dimethylformamide (DMF) under anhydrous conditions. These products were sparingly soluble in organic solvents even when hot, and lacked stability in mineral acids. Their nature was determined by fast atom beam mass spectrometry (FAB MS), 1H NMR (3b) and elemental analysis. Information about the geometry of the complexes could not be obtained by UV-Vis spectroscopy. The electronic spectra of 3a,b in trifluoroacetic anhydride (TFAA) show very intense bands in the UV region for the two complexes, which have been attributed to 7r~ 7r* transitions on the ligand. In the case of 3a a low-energy band at 627 nm, with a low molar absorption coefficient, is also observed. This is almost certainly due to d-d transitions. An alternative method for the preparation of compounds 3 would be the condensation of the three-unit

S. Rodn'guez-Morgade, T. Torres / lnorganica Chimica Acta 230 (1995) 153-157

metal complexes 7 with 1,3-diaminobenzene. The threeunit compound 4e [3,11], related to 4a and 4b, with a central pyridine subunit, behaves as a tridentate divalent ligand towards Cu(II) and Ni(II), affording the metal complexes 8a,b [18]. This fact has been used for the stabilization of the free ligand 4c in macrocyclization reactions [18]. In the case of compounds 4a and 4b, similar complexes (having, however, two copper(II) atoms), such as 9a, have been reported [19]. N-NH

NH

HN

NH

HN

7 ='

M = Cu(II)

$11

M = Cu(ll)

7b

M=Ni(II)

8b

M=Ni(II)

Now, we have prepared the copper and nickel complexes 7a,b by reaction of triazole 4a with one equivalent of the corresponding metal(II) acetate. The compounds were characterized by FAB MS and elemental analysis. This reaction is very sensitive to the stoichiometry of the reactants. In all cases, the the presence of various amounts of dimetallic compounds, probably of structure 9 [19], was detected by FAB MS in the crude reaction products. The amounts of these compounds increase with temperature and reaction time, and they become the major products if a metal salt:triazole 4a ratio higher than 2:1 is used. In these cases compounds 9a and 9b were always accompanied by 7a and 7b, respectively, and by impurities of higher molecular weight. This fact, together with their low solubility in common organic solvents, prevented their correct purification. The structure assignment for compounds 9a and 9b has been made based on their FAB mass spectra. N--NH

N~Gu~N 9a

M

9b

M =Ni(ll)

=

Cu(II)

Compounds 7a and 7b have higher thermal stability than the free ligand 4a, but according to the FAB mass spectral data, they also rearrange upon prolonged heating to afford a mixture of compounds, which were not identified. However, all attempts to obtain 3a,b by condensation of the preceding metal complexes 7a,b with 1,3-diaminobenzene were unsuccessful. When the reaction was carried out in 2-ethoxyethanol at reflux temperature, unreacted compounds 7a,b were recovered as the major products. Under more vigorous conditions,

155

upon prolonged heating in ethylene glycol at reflux temperature, there was degradation of the starting materials. Perhaps the desired condensation reaction was not achieved because of the low reactivity with aromatic diamines of the 'outer' iminic double bonds 7a,b, as a consequence of the metal coordination. In conclusion, the preceding results show that satisfactory syntheses of compounds 3a,b are achieved only through metallation of the free mixed macrocycle 2, whose preparation has been described in this paper. Triazolehemiporphyrazines 2 and 3 show electrical conductivities in the range of the isolators ( < 10-12 S cm-l). The NLO properties of the new compounds are presently being studied.

3. Experimental Electron impact (EI) (70 eV) and fast atom beam (m-nitrobenzyl alcohol (m-NBA) and sulfuric acid as matrix) mass spectra were determined on Varian MAT 312 and Finnigan HSQ-30 instruments, respectively, with an incorporated SS 300 MS data system. IR spectra were recorded on a Perkin-Elmer model 257 spectrometer. UV-Vis spectra were recorded on a PerkinElmer Lambda 6 instrument. NMR spectra were obtained with a Bruker WP 200 SY instrument. Conductivity measurements were performed using a twoprobe geometry in pressed pellets at a pressure of 1 kbar.

3.1. 5, 25:7,10:12,17-Ttiimino-23,19-metheno-19Hdibenzo [ f, q] [ 1, 2, 4, 9,15, 20]hexaazacycloheneicosine (2) 3.1.1. From 3, 5-bis(3'-imino-l '-isoindolinylideneamino)1, 2, 4-triazole (4a) A mixture of 4a (1.06 g, 3 mmol) and 1,3-diaminobenzene (324 mg, 3 mmol) in 2-ethoxyethanol (25 ml) was heated at reflux temperature for 48 h. The mixture was cooled, and the solid was isolated by filtration and then triturated with hot ethanol. The product was identified as the triazolehemiporphyrazine 5a [1] (461 mg, 36%), m.p. >300 °C. The filtrate was evaporated at reduced pressure and the residue was triturated with hot ethanol to yield 2 (337 mg, 26%), m.p. 285 °C (decomp.). Anal. Calc. for C24H15Ng-H20: C, 64.42; H, 3.83; N, 28.17. Found: C, 64.32; H, 3.83; N, 27.82%. IR (KBr, cm- 1): 3340 (N-H), 3210 (N-H), 3040, 2910, 1720, 1645 (v br, C = N), 1480 (C=N, triazole), 1365, 1310, 1200, 1100, 1050, 765 (C-H), 690 (C-H). UV-Vis (TFAA) (A (logE)): 258 (4.51), 344 (4.52) nm. 1H NMR (TFAA-dl): ~ 8.4 (m, 4H, H-l,4), 8.1 (m, 7H, H-2,3,20,26), 7.8 ppm (m, 1H, H-21). 13C NMR (TFAA-dI): 6 163.8 (C-5, C-17), 154.0 (C-7), 135.3, 134.5, 133.6 (C-2, C-3, C-19), 131.0, 130.7,

156

S, Rodrfguez-Morgade, T. Torres /Inorganica Chimica Acta 230 (1995) 153-157

127.6 (C-4a, C-25a, C-26), 124.2, 123.5, 123.3 (C-1, C4, C-20), 117.9 (C-21) ppm. E1 MS: m/z 429 (M ÷, 98%), 228 (82), 130 (64), 99 (100). High-resolution E1 MS: m/z calc. for C24H15N9: 429.1450. Found: 429.1485 (M +). After evaporation of the ethanol solution, the residue was chromatographed on silica gel using dichloromethane as eluent. The compound was identified as the macrocycle 5b [16] (290 mg, 23%).

3.1.2. From 1, 3-bis(3'-imino- l '-isoindolinylideneamino)benzene (4b) A mixture of 1,3-bis(3'-imino-l'-isoindolinylideneamino)benzene 4b (728 mg, 2 mmol) and 3,5-diamino1,2,4-triazole (guanazole) (198 mg, 2 mmol) was heated in 2-ethoxyethanol (25 ml) at reflux temperature for 48 h. The mixture was cooled, and 5a (254 mg, 29%) was isolated by filtration and then triturated with hot ethanol. The filtrate was treated as described above, affording 2 (322 mg, 37%) and 5b (191 rag, 23%). 3.1.3. Preparation of 2 by a statistical route A mixture of 1,3-diiminoisoindoline (580 rag, 4 mmol), 1,3-diaminobenzene (216 rag, 2 mmol) and guanazole (198 mg, 2 mmol) was heated in 2-ethoxyethanol at reflux temperature for 48 h. The following compounds were isolated using the method described above: 2 (362 mg, 42%), 5a (142 mg, 17%) and 5b (241 mg, 23%). 3.2. 5, 25:7,10:12,17-Triimino-23,19-metheno-19Hdibenzo [ f, q] [ 1, 2, 4, 9,15, 20]hexaazacycloheneicosinaw (2-)-N 2~,N 2s,N 29,copper(II) (3a) A mixture of 2 (160 mg, 0.36 mmol) and copper(II) bromide (116 mg, 0.52 mmol) was heated under argon in dry DMF at reflux temperature for 48 h. The precipitate was filtered and triturated with hot ethanol to give 3a (123 mg, 70%), m.p. > 300 °C. Anal. Calc. for C24HlaCuN9"n20: C, 56.63; H, 2.97; N, 24.75. Found: C, 56.92; H, 3.30; N, 23.84%. 1R (KBr, cm-~): 3155 (N-H), 2920, 2855, 1625 (C = N), 1560 (br, C = N), 1470 (C=N, triazole), 1370, 1315, 1200, 1100, 760 (C-H), 710 (C-H). UV-Vis (TFAA) (A (loge)): 258 (4.78), 355 (4.65), 495 (sh) nm. FAB MS (m-NBA/TFAA): m/z 491, 493 (M + H +).

3.3. 5, 25:7,10:12,17-Triimino-23,19-metheno-19Hdibenzo [ f, q] [ 1, 2, 4, 9,15, 20]hexaazacycloheneicosinato (2-)-N 26,U 2s,U% nickel(lI) (3b) Compound 3b was obtained by the procedure described above for 3a, starting from 2 (160 mg, 0.36 mmol) and nickel(ll) bromide (114 mg, 0.52 mmol) (yield 119 mg (68%), m.p. >300 °C). Anal. Calc. for C24H13NiN9.H20: C, 57.18; H, 3.00; N, 25.00. Found: C, 57.05; H, 3.03; N, 24.71%. 1R (KBr, cm-~): 3150 (N-H), 2980, 2920, 1630 (C = N), 1570 (br, C = N), 1470

(C=N, triazole), 1380, 1315, 1190, 1100, 760 (C-H), 705 (C-H). UV-Vis (TFAA) (A (logE)): 257 (4.37), 351 (4.25), 627 (2.38) nm. aH NMR (TFAA-dl): 6 8.3-7.5 (3 m, arom. H) ppm. FAB MS (m-NBA/TFAA): m/z 486, 488 (M + H +).

3.4. Preparation of the metal complexes 7a, b 3.4.1. Copper complex 7a A solution of 4a (500 mg, 1.41 mmol) and copper(II) acetate monohydrate (281 mg, 1.41 mmol) was heated in 2-ethoxyethanol (25 ml) at 80 °C for 90 min. After cooling, the precipitate was separated by centrifugation and washed with hot ethanol. Yield 451 mg (77%), m.p. >300 °C. Anal. Calc. for C18H11CuN9"2H20: C, 47.73; H, 3.34; N, 27.83. Found: C, 46.94; H, 3.83; N, 27.43%. 1R (KBr, cm-1): 1660 (C=N), 1610 (C=N), 1555, 1470 (C=N, triazole), 1315, 1105, 760 (C-H), 700 (C-H). FAB MS (m-NBA/TFAA): m/z 417, 419 (M+H+). High-resolution FAB MS: m/z calc. for C18HlzCuN9: 417.0512. Found: 417.0536 (M+H+). 3. 4.2. Nickel complex 7b Compound 7b was obtained by the procedure described above for 7a, starting from 4a (500 mg, 1.41 mmol) and nickel(I1) acetate tetrahydrate (350 mg, 1.41 mmol). Yield 477 mg (82%), m.p. > 300 °C. Anal. Calc. for C18HllNiNg'2H20: C, 48.25; H, 3.37; N, 28.13. Found: C, 47.70; H, 3.58; N, 27.49%. IR (KBr, cm-1): 1650 (C = N), 1595 (C = N), 1550, 1470 (C = N, triazole), 1330, 1105, 760 (C-H), 715 (C-H). FAB MS (m-NBA/ TFAA): m/z 412, 414 (M+H+). High-resolution FAB MS: m/z calc. for C18H12NiNg:412.0569. Found: 412.0585 (M+H+). When the above reactions were carried out with a 1:2 molar ratio of 4a and the corresponding metal salt and the reaction time was prolonged by 24 h, the FAB mass spectra of the crude reaction products showed very intense peaks at m/z 479 and 469, respectively, probably corresponding to the dimetallic compounds 9a,b [19]. 3.4.3. Attempts at condensation of 7a, b with 1, 3-diaminobenzene A mixture of 7a or 7b (1 nunol) and 1,3-diaminobenzene (1 retool) was heated in 2-ethoxyethanol (20 ml) at reflux temperature (135 °C) for 48 h. The precipitate was filtered and washed with hot ethanol. The residue was analysed by FAB MS and was seen to be a mixture of the starting material (major component) and other compounds of high molecular weight.

Acknowledgements This work was supported by the Comisi6n Interministerial de Ciencia y Tecnologia (CICYT) through

S. Rodrfguez-Morgade, T. Torres / Inorganica Chimica Acta 230 (1995) 153-157

grants MAT-90-0317 and MAT-93-0075, which are gratefully acknowledged.

References [1] F. Fern,qndez-IAzaro, J. de Mendoza, O. M6, S. RodrlguezMorgade, T. Torres, M. Y,Sfiez and J. Elguero, J. Chem. Soc., Perkin Trans. 2, (1989) 797. [2] F. Fernfindez-IAzaro, Ph.D. Thesis, Universidad Aut6noma de Madrid, 1992. [3] F. Fern,'indez-IAzaro, S. Rodriguez-Morgade and T. Torres, Synth. Met., 62 (1994) 281. [4] C.C. Leznoff and A.B.P. Lever (eds.),Phthalocyanines: Properties and Applications, Vols. 1, 2 and 3, VCH, Weinheim, 1989 and 1993; H. Schultz, H. Lehman, M. Rein and M. Hanack, Struct. Bonding (Berlin), 74 (1990) 41-146. [5] J.A. Duro, J.M. Ontoria, A. Sastre, W. Sch/ifer and T. Torres, J. Chem. Soc., Dalton Trans., (1993) 2595. [6] D. Li, M.A. Ratner and T.J. Marks, J. Am. Chem. Soc., 110 (1988) 1707. [7] T. Torres and F. Fernfindez-Lfizaro, Spanish Patent No. P9202 185 (1992). [8] M.A. Diaz-Garcfa, I. Ledoux, F. Fernfindez-lAzaro, A. Sastre, T. Torres, F. Agull6-L6pez and J. Zyss, 1st Int. Conf. on Organic Nonlinear Optics, Val Torens, France, 9-13 Jan. 1994; M.A. Dfaz-Garcia, I. Ledoux, F. Fernfindez-Lfizaro, A. Sastre, T. Torres, F. Agull6-L6pez and J. Zyss, J. Phys. Chem., 98 (1994) 4495. [9] H.S. Nalwa, Appl. Organomet. Chem., 5 (1991) 349; ICS. Suslick, Ch.-T. Chen, G.R. Meredith and L.-T. Cheng, J. Am. Chem. Soc., 114 (1992) 6928; Z.Z. Ho, C.Y. Ju and W.M. Hetherington

[10]

[11]

[12] [13] [14]

[15]

[16] [17] [18] [19]

157

III, J. Appl. Phys., 62 (1987) 716; M. Hosoda, T. Wada, A. Yamada, A.F. Garito and H. Sasabe, Jpn. J. Appl. Phys., 30 (1991) 1715; J.R. Shirk, J.R. Lindle, F.J. Bartoli, Z.H. Kafafi, A.W. Snow and M.E. Boyle, Int. J. Nonlinear Opt. Phys., 1 (1992) 699; A. Grund, A. Kaltbeitzel, A. Mathy, R. Schwarz, C. Bubeck, P. Vermehren and M. Hanack, J. Phys. Chem., 96 (1992) 7450; H.S. Nalwa, A. Kakuta and A. Mukoh, J. Phys. Chem., 97 (1993) 1097. A.V. Sokolov, R.P. Smirnov, M.I. Bazanov, M.K. Islyaikin and E.A. Danilova, Izv. Vyssh. Uchebn. Zaved., Khim. ghim. Tekhnol., 32 (6) (1989) 38 (Chem. Abstr., 112 (1990) 158216r). J.A. Elvidge and N.R. Barot, in S. Patai (ed.), The Chemistry of Double-Bonded Functional Groups, Part 2, Wiley, New York, 1977, pp. 1167-1249. M. Hanack, K. Haberroth and M. Rack, Chem. Ber., 126 (1993) 1201. P.F. Clark, J.A. Elvidge and R.P. Linstead, J. Chem. Soc., (1954) 2490. V.F. Borodkin and N.A. Kolesnikov, Khim. Geterotsild. Soedin., 7 (2) (1971) 194 (Chem. Abstr., 75 (1971) 35981w); R.P. Smirnov, V.A. Gnedina and V.F. Borodkin, Khim. Geterotsikl. Soedin., 6 (1969) 1102 (Chem. Abstr., 73 (1970) 10243c). R.P. Smirnov, V.A. Gnedina and V.F. Borodkin, Tr. Vses. Mezhvuz. Nauch.- Tekh. Konf. Vop. Sin. Primen. Krasitelei, 1970, p. 17 (Chem. Abstr., 76 (1972) 145180; N.A. Kolesnikov, V.F. Borodkin and L.M. Fedorov, Izv. Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol., 16 (7) (1973) 1084 (Chem. Abstr., 79 (1973) 105222h). M.E. Baguley and J.A. Elvidge, J. Chem. Soc., (1957) 709. J.A. Elvidge and J.H. Golden, Z Chem. Soc., (1957) 700. P. Bamfield and P.A. Mack, J. Chem. Soc. C, (1968) 1961. V.A. Gnedina, R.P. Smirnov and G.A. Matyushin, lzv. Vyssh. Uchebn. Zaved., Khim. Khim. TekhnoL, 16 (4) (1973) 589 (Chem. Abstr., 79 (1973) 93420f).