GAO Dn-Dn GAO Qin CHEN Yn-Mei LI Y-Hong LI Wu



Syntheses, Structures, and Luminescent Properties of the ZnIIand CdII1-Chain Polymers Assembled by SalicylhydroxamicAcid①

GAO Dan-DanaGAO QianbCHEN Yan-MeibLI Ya-Hongb②LI Wua②

a(810008)b(215123)

Two complexes of compositions[Zn(H2shi)(CH3COO)](1)and [Cd(H2shi)2(H2O)](2)(H3shi = salicylhydroxamic acid) have been prepared under solvothermal conditions. They are characterized by X-ray single-crystal diffraction, IR and elemental analysis. The crystal of 1 belongs to the tetragonal system, space group41/with= 18.972(3),= 18.972(3),= 10.938(2) Å,= 3937.1(1) Å3, C9H9NO5Zn,M= 276.54,= 16,D= 1.866 g/cm3,= 2.500 mm-1,(000) = 2240, the final= 0.0425 and= 0.123. The crystal of 2 belongs to the monoclinic system, space group2/with= 16.647(3),= 6.4577(1),= 6.5623(1) Å,= 702.4(2) Å3, C14H14Cd2N2O7,M= 434.68,= 2,D= 2.055 g/cm3,= 1.599 mm-1,(000) = 432, the final= 0.0211 and= 0.0761. They both possess 1-polymeric chain structures. The luminescent properties of complexes 1 and 2 have been investigated.

hydroxamic acids, zinc complex, cadmium complex, 1-polymeric chain, luminescent property;

1 INTRODUCTION

Hydroxamic acids (HAs)are a valuable class of bioligands and have been extensively employed in chemical biology[1]. They possess high metal- chelating affinity and exhibit versatile coordination modes. These properties make hydroxamic acids to be powerful ligands to construct homometallic or heterometallic polynuclear clusters and chain com- plexes[2-5]. Recent advances in the coordination chemistry of hydroxamic acids reveal that the coordination behaviors of hydroxamic acid can be tuned by the incorporation of different functional groups,, -NMe2[2], -OH[6], -NH2[7],., at ortho, meta and (or) para positions of the phenyl ring, generating coordination complexes with fascinatingconfigurations and useful properties.

Salicylhydroxamic acid (H3shi) is a member of a big family of hydroxamic acids. It shows rich coordination modes[8-18](Scheme 1) due to the extra hydroxyl group at theposition of phenyl ring. H3shi acted as a polydentate ligand to afford mo- nonuclear complexes with Ru[18], V[14]and Pt[13], generating polynuclear compounds with Cu[10], Mo[11], and V[12]as well as polynuclear heterome- tallic Mn-Ho and Mn-Dy complexes[10]. To our surprise, no polynuclear coordination complexes of ZnIIand CdIIare reported. As is well known, coor- dination complexes of ZnIIand CdIIhave attracted a great deal of interest due to their potential applica- tions in fluorescence-emitting materials[19-21], such as light-emitting diodes (LEDs) and organic light- emitting diodes (OLEDs)[22], in biological systems,cleavage of DNA, RNA and amino acid esters, etc.[23-27], and in organic synthesis[28]. To further explore the coordination chemistry of salicylhydro- xamic acid with ZnIIand CdII, we conducted the reaction of salicylhydroxamic acid with Zn(CH3COO)2·2H2O and Cd(CH3COO)2·2H2O, respectively. Two new 1-polymeric chain com- plexes with formulas [Zn(H2shi)(CH3COO)](1)and [Cd(H2shi)2(H2O)](2) were synthesized. Herein, we report the syntheses, structures and luminesient properties of these two complexes.

Scheme 1. Coordination modes of H3shi

2 EXPERIMENTAL

2. 1 Materials and physical measurement

All chemicals were purchased from commercial suppliers and used without further purification. The C, H and N microanalyses were carried out with a Carlo-Erba EA1110 CHNO-S elemental analyzer. FT-IR spectra were recorded from KBr pellets in the range of 400～4000 cm-1on a Nicolet MagNa- IR500 spectrometer. Crystal determination was performed with a Bruker SMART APEX ΙΙ CCDC diffractometer equipped with graphite-mono- chromatized Moradiation (= 0.71073 Å). The solid-state luminescence emission/excitation spectra were recorded on a FLS920 fluorescence spectro- photometer equipped with a continuous Xe-900 xenon lamp and aF900 microsecond flash lamp. Powder X-ray diffraction (PXRD) was recorded on a Rigaku D/Max-2500 diffractometer.

2. 2 Syntheses of the complexes

2. 2. 1 Synthesis of [Zn(H2shi)(CH3COO)](1)

A mixture of Zn(CH3COO)2·2H2O (0.0216 g, 0.10 mmol), H3shi (0.0153 g, 0.10 mmol), and H2O (1.0 mL) was placed in a Pyrex-tube. The tube was heated at 80­℃­for 6 days. After being cooled to room temperature, pale yellow crystals of the product were afforded. The crystals were collected by filtration, washed with H2O (2 mL) and dried in air. Yield: 40% (based on Zn). Anal. Calcd. (%) for C9H9NO5Zn: C, 39.09; H, 3.28; N, 5.06. Found (%): C, 38.96; H, 3.15; N, 5.01. IR (KBr, cm-1): 3274(s), 1612(s), 1551(s), 1481(s), 1367(m), 1250(m), 1153(s), 1059(s), 1031(m), 925(s), 812(m), 751(m).

2. 2. 2 Synthesis of [Cd(H2Shi)2(H2O)](2)

A mixture of Cd(CH3COO)2·2H2O (0.0207 g, 0.10 mmol), H3shi (0.0153 g, 0.10 mmol), and H2O (1.0 mL) was placed in a Pyrex-tube. The tube was heated at 80 ℃­for 7 days. After being cooled to room temperature, pale yellow crystals of the product were afforded. The crystals were collected by filtration, washed with H2O (2 mL) and dried in air. Yield: 56% (based on Cd). Anal. Calcd. (%) for C14H14Cd2N2O7: C, 38.68; H, 3.25; N, 6.44. Found (%): C, 38.76; H, 3.21; N, 6.38. IR (KBr, cm-1): 3468(m), 3015(w), 1613(s), 1549(s), 1481(s), 1417(s), 1341(s), 1250(s), 1153(s), 1122(s), 1050(s), 925(s), 812(m), 751(s), 659(s).

2. 3 X-ray crystal structure determination

The single crystals of complexes 1 and 2 were determined with Moradiation using a Bruker SMART APEX-II CCD diffractometer at 296(2) K for 1 and 293(2) K for 2 using the-2scan mode. For complex 1, in the range of 2.15≤≤28.42o, a total of 13821 reflections were obtained with 2490 unique ones and used in the refinements. For complex 2, in the range of 3.39≤≤27.49o, a total of 5355 reflections were obtained with 1573 unique ones and used in the refinements. The structures were solved by direct methods and refined with full-matrix least-squares on2using SHELXS-97[29]and SHELXL-97[30]. The selected bond lengths and bond angles of complexes 1 and 2 are listed in Table 1.

Table 1. Selected Bond Lengths (Å) and Bond Angles (°)

3 RESULTS AND DISCUSSION

3. 1Structure descriptions of the complexes

3. 1. 1Structure of complex 1

The crystal structure analysis reveals that 1 crystallizes in the tetragonal crystal system, space group41/. The asymmetric unit(Fig. 1) consists of one crystallographically independent ZnIIatom, one H2shi-ligand and one acetate ion. The ZnIIion is penta-coordinated by one carboxyl oxygen atom, one2-hydroxamate oxygen atom and one1- hydroxamate oxygen atom from two H2shi-ligands, and two oxygen atoms from acetate ions, displaying distorted tetragonal geometry. The adjacent ZnIIions are doubly connected by two oxygen atoms of the acetate ion and one hydroxamate oxygen atom to generate an infinitive 1-chain structure (Fig. 2). The Zn–O/N bond lengths are in the range of 1.983(2)～2.095(3) Å. The ZnII···ZnIIdistance is 3.6506(7) Å. The H2shi-ligands possess the coor- dination mode F (Scheme 1).

Fig. 1. Coordination environment of the Zn ion in 1. Hydrogen atoms have been omitted for clarity.Color scheme: blue, ZnII; red, oxygen; dark blue, nitrogen; yellow, carbon

Fig. 2. 1-chain structure of 1. Hydrogen atoms are omitted for clarity.Color scheme: blue, ZnII; red, oxygen; dark blue, nitrogen; yellow, carbon

3. 1. 2Structure of complex 2

The crystal structure analysis reveals that 2 crystallizes in monoclinic, space group2/. The crystal structure of 2 (Fig. 3) consists of one CdIIion and two singly deprotonated H2shi-ligands and one coordinated water molecule. The adjacent CdIIions are bridged by the hydroximate oxygen atoms to form a one-dimensional linear chain(Fig. 4). Each CdIIion is bound toseven oxygen atoms (O1, O1A, O3A, O3B,2-O1B,2-O1C, and O1W) originated from four different H2shi-ligands and one water molecule. Each H2shi-ligand chelates one CdIIion through a1-carbonyl oxygen atom and a2-hydroxamate oxygen atom (coordination mode F in Scheme 1), with the Cd–O distances ranging from 2.341(2) to 2.432(16) Å. The Cd···Cd distance is 3.7392(6) Å.

Remarkably, complexes 1 and 2 were prepared by using similar starting materials, but their com- positions and structures are totally different, indica- ting that metal ions play key roles in the construc- tion of coordination polymers.

Complexes 1 and 2 join a big family of coor- dination polymersof ZnII/CdII[31-36].However, the ZnIIand CdII1-chain complexes supported by the H3shi ligand are never reported.

Fig. 3. Coordination environment of the Cd ion in 2. Hydrogen atoms have been omitted for clarity.Color scheme: green, CdII; red, oxygen; blue, nitrogen; yellow, carbon

Fig. 4. 1-chain structure of 2. Hydrogen atoms are omitted for clarity.Color scheme: green, CdII; red, oxygen; blue, nitrogen; yellow, carbon

3. 2 Powder X-ray diffraction (PXRD)

In order to check the phase purity of complexes 1 and 2, the powder X-ray diffractions (PXRD) have been measured and compared with those simulated from the single-crystal structure data. As can be seen from Figs. 5 and 6, the experimental PXRD patterns and simulated peaks match well, indicating the purities of the complexes.

3. 3 Luminescent property

The luminescent properties of the H3shi ligand and complexes 1 and 2 were investigated in the solid state at room temperature (Fig.7). The H3shi ligand shows photoluminescence emission at 344 nm. Complex 1 shows emission with the maximum peak at 356 nm. Compared with the H3shi ligand, the red-shifted emission of 1 may be ascribed as the intraligand charge transfer (-*)[33, 37]. The pro- nounced fluorescence emission of complex 1 reveals its potential application in photoactive materials.

Fig. 5. Powder XRD patterns of complex 1

Fig. 6. Powder XRD patterns of complex 2

Fig. 7. Emission spectra of the H3shi ligand and complex 1in the solid state at room temperature (Emission slit = 1 nm)

No emission was observed for complex 2. The water in lattice may prevent an efficient intraligand charge transfer.

4 CONCLUSION

In summary, two 1D chain ZnIIand CdIIcom- plexes of compositions [Zn(H2shi)(CH3COO)](1)and [Cd(H2shi)2(H2O)](2)have been prepared under solvothermal conditions. The luminescent properties have been investigated. Complex 1 shows red-shifted luminescence emission. The pronounced fluorescence emission of 1 reveals its potential applications for photoactive materials.

(1) Codd, R. Traversing the coordination chemistry and chemical biology of hydroxamic acids.2008, 252, 1387–1408.

(2) Gaynor, D.; Starikova, Z. A.; Ostrovsky, S.; Haase, W.; Nolan, K. B. Synthesis and structure of a heptanuclear nickel(II) complex uniquely exhibiting four distinct binding modes, two of which are novel, for a hydroxamate ligand.. 2002, 506–507.

(3) Jankolovits, J.; Andolina, C. M.; Kampf, J. W.; Raymond, K. N.; Pecoraro, V. L. Assembly of near-infrared luminescent lanthanide host(host-guest) complexes with a metallacrown sandwich motif.. 2011, 50, 9660–9664.

(4) Eltayeb, A. Z.; Nimir, H. I.; Brown, D. A.; Lan, Y.; Anson, C. E.; Powell, A. K. Magnetic and structural studies of novel tetranickel hydroxamates.2010, 363, 899–904.

(5) Bai, Y.; Guo, D.; Duan, C. Y.; Dang, D. B.; Pang, K. L.; Meng, Q. J. A three-dimensional porous metal-organic framework [Fe4L6·(DMF)3·(H2O)10] constructed from neutral discrete Fe4L6pyramids (H2L = 1,3-benzodihydroxamix acid).. 2004, 186–187.

(6) Gajewska, M.; Luzyanin, K. V.; Guedes da Silva, M. F. C.; Li, Q. S.; Cui, J. R.; Pombeiro, A. J. L. The first tin compounds bearing oximehydroxamate ligands.. 2009, 3765–3769.

(7) Alagha, A. B. M.; Gaynor, D.; Muller-Bunz, H.; Nolan, K. B.; Parthasarathi, L. fac-Tris(4-amino-benzohydroxamato)iron(III) ethanol solvate.2010,66, m853–854.

(8) Lah, M. S.; Pecoraro, V. L. A functional analogy between crown ethers and metallacrowns.1991, 30, 878–880.

(9) Zaleski, C. M.; Kampf, J. W.; Mallah, T.; Kirk, M.; Pecoraro, V. L. Assessing the slow magnetic relaxation behavior of LnIII4MnIII6metallacrowns.2007, 46, 1954–1956. I

(10) Gibney, B. R.; Kessissoglou, D. P.; Kampf, J. W.; Pecoraro, V. L. Copper(II) 12-metallacrown-4: synthesis, structure, ligand variability, and solution dynamics in the 12-MC-4 structural motif.1994, 33, 4840–4849.

(11) Liu, S. C.; Zhu, H. Z.; Zubieta, J. Reactions of polyoxomolybdates with oximes. The crystal and molecular structures of [(C4H9)4N]2[Mo2O5C6H4(O)CHNO2]·CH2Cl2and [(C4H9)4N]2[Mo2O5C6H5CH(O)C(NO)C6H52].1989, 8, 2473–2480.

(12) Si,eT. K.; Chakraborty, S.; Mukherjee, A. K.; Drew, M. G. B.; Bhattacharyy, R. Novel supramolecular network in tri- and mono-nuclear oxovanadium(V)-salicyl-hydroximate: synthesis, structure and catalytic oxidation of hydrocarbons using H2O2as terminal oxidant..2008, 27, 2233–2242.

(13) 2Henderson, W.; Evans, C.; Nicholson, B. K.; Fawcett, J. Coordination isomerism in salicylhydroxamate complexes of platinum(II) and palladium(II).2003, 2691–2697.

(14) Cornman,6C. R.; Colpas, G. J.; Hoeschele, J. D.; Kampf, J.; Pecoraro, V. L. Implications for the spectroscopic assignment of vanadium biomolecules: structural and spectroscopic characterization of monooxovanadium(V) complexes containing catecholate and hydroximate based noninnocent ligands.1992,114, 9925–9933.

(15) Stemmier, A. J.; Kampf, J. W.; Kirk, M. L.; Pecoraro, V. L. A model for the inhibition of urease by hydroxamates.11995, 117, 6368–6369.

(16) Centore, R.; Tommaso, G. D.; Iuliano, M.; Tuzi, A. An organouranium coordination polymer containing infinite metal oxide chains.52007, C63, m253–m255.

(17) Tekeste, T.; Vahrenkamp, H. Enzyme inhibitor modeling with TpZn complexes of functional hydroxamates and oximates.52007, 360, 1523–1528.

(18) Comiskey, J.; Farkas, E.; Krot-Lacina, K. A.; Pritchard, R. G.; McAuliffe, C. A.; Nolan, K. B. Synthesis, structures and speciation studies of ruthenium(III) hydroxamate/hydroximato complexes. Crystal and molecular structure of hydrated [Ru(H2edta)(2-methoxyphenylhydroxamate)], the first structurally characterised ruthenium(III)-hydroxamate complex.2003, 4243–4249.

(19) Katsoulakou, E.; Bekiari, V.; Raptopoulou, C. P.; Terzis, A.; Manessi-Zoupa, E.; Powell, A.; Perlepes, S. P. Simultaneous coordination of a ketone by two cadmium(II) ions and conversion to its gem-​diolate(-​1) form.2011, 14, 1057–1060.

(20) Eom, G. H.; Park, H. M.; Hyun, M. Y.; Jang, S. P.; Kim, C.; Lee, J. H.; Lee, S. J.; Kim, S. J.; Kim, Y. Anion effects on the crystal structures of ZnIIcomplexes containing 2,​2΄-​bipyridine: their photoluminescence and catalytic activities.2011, 30, 1555–1564.

(21) Cui, P.; Chen, Z.; Gao, D. L.; Zhao, B.; Shi, W.; Cheng, P. Syntheses, structures, and photoluminescence of a series of three-​dimensional CdIIframeworks with a flexible ligand, 1,​5-​bis(5-​tetrazolo)​-​3-​oxapentane.2010, 10, 4370–4378.

(22) Wang, R. J.; Deng, L. J.; Fu, M.; Cheng, J. L.; Li, J. Y. Novel ZnIIcomplexes of 2-(2-hydroxyphenyl)benzothiazoles ligands: electroluminescence and application as host materials for phosphorescent organic light-emitting diodes.2012, 22, 23454–23460.

(23) Guha, A.; Chattopadhyay, T.; Paul, N. D.; Mukherjee, M.; Goswami, S.; Mondal, T. K.; Zangrando, E.; Das, D. Radical pathway in catecholase activity with zinc-​based model complexes of compartmental ligands.2012, 51, 8750–8759.

(24) Panja, A.; Matsuo, T.; Nagao, S.; Hirota, S. DNA cleavage by the photocontrolled cooperation of ZnIIcenters in an azobenzene-​linked dizinc complex.2011, 50, 11437–11445.

(25) Feng, G. Q.; Natale, D.; Prabaharan, R.; Mareque-Rivas, J. C.; Williams, N. H. Efficient phosphodiester binding and cleavage by a ZnIIcomplex combining hydrogen-​bonding interactions and double Lewis acid activation.2006, 45, 7056–7059.

(26) Scrimin, P.; Tecilla, P.; Tonellato, U.; Valle, G.; Veronese, A. A zinc(II)​-​organized molecular receptor as a catalyst for the cleavage of amino acid esters.1995, 1163–1164.

(27) Jang, K. J.; Yeo, G. Y.; Cho, T. S.; Eom, G. H.; Kim, C.; Kim, S. K. Real-​time detection of DNA cleavage induced by [M(2,​2΄-​dipyridylamine)2(NO3)​n]​+(M = Cd, Cu, Ni, Zn, n = 1, 2,= 0,​1)​: effect of central metal ions.2010, 148, 138–143.

(28) Meng, X. R.; Song,Y. L.; Hou, H. W.; Han, H. Y.; Xiao, B.; Fan, Y. T.; Zhu, Y. Hydrothermal syntheses, crystal structures, and characteristics of a series of Cd-btx coordination polymers (btx = 1,4-bis(triazol-1-ylmethyl)benzene).. 2004, 43, 3528–3536.

(29) Sheldrick,G. M.University of Göttingen, Germany1997.

(30) Sheldrick,G. M.. University of Göttingen, Germany1997.

(31) Brown, D. A.; Fitzpatrick, N. J.; Müller-Bunz, H.; Ryan, A. T. Di-, tri-, and tetranuclear zinc hydroxamate complexes as structural models for the inhibition of zinc hydrolases by hydroxamic acids.. 2006, 45, 4497–4507.

(32) Alexiou, M.; Dendrinou-Samara, C.; Raptopoulou, C. P.; Terzis, A.; Kessissoglou, D. P. From monomer zinc-oxamato complexes to tetranuclear inverse 12-membered and octanuclear 12-membered metallacrowns.. 2002, 41, 4732–4738.

(33) Chen, Y. M.; Gao, Q.; Liu, Y. L.; Cao, Y. Y.; Gao, D. D.; Liu, J. N.; Zhao, J. J.; Li, Y. H.; Liu, W.; Li, W. Synthesis, crystal structures and luminescent properties of CdIIand ZnIIcomplexes assembled by 4-aminophenylhydroxamic acid.2014, 4, 147–153.

(34) Chen, W. T.; Yi, X. G.; Wen, J. W. Synthesis, crystal structure and property of (CdCl3)n·nH3O with a one-dimensional infinite chain-like structure.2014, 26, 1253–1254.

(35) Chen, W. T.; Hu, R. H.; Yi, X. G.; Wang, Y. F.; Luo, Z. G.; Fu, H. R.; Liu, J.; Chen, H. L. Synthesis, structure, properties and time-dependent density functional theory calculations of cadmium complex.2014, 26, 4865–4867.

(36) Chen, W. T.; Hu, R. H.; Luo, Z. G.; Chen, H. L.; Zhang, X.; Liu, J. [N-ethyl-4,4΄-bipyridinium][ZnX4] (X = Cl or Br) with N-ethyl-4,4΄-bipyridinium generated: syntheses, structures, fluorescence and TDDFT calculations.2014, 33, 1141–1146.

(37) Zheng, S. L.; Yang, J. H.; Yu, X. L.; Chen, X. M.; Wong, W. T. Syntheses, structures, photoluminescence and theoretical studies of10metal complexes of 2,2΄-dihydroxy-[1,1΄]binaphthalenyl -3,3΄-dicarboxylate.. 2004, 43, 830–838.

①Supported by the National Natural Science Foundation of China (21272167, 51404234 and U140710123), a project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institution and KLSLRC (KLSLRC-KF-13-HX-1)

. Li Ya-Hong, born in 1968, professor, majoring in organometallic chemistry. E-mail: liyahong@suda.edu.cn; Li Wu, born in 1966, professor, majoring in inorganic chemistry. E-mail: driverlaoli@163.com

10.14102/j.cnki.0254-5861.2011-0675

9 February 2015; accepted13 July 2015 (CCDC 996953 for 1 and 996946 for 2)