Stud ies on Α-M ethacryla te Copper (g ) Com plexes w ith Im idazole 3

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1 V o l. 15 N o Chem ical R esearch in Ch inese U niversities Stud ies on Α-M ethacryla te Copper (g ) Com plexes w ith Im idazole 3 W AN G Yao2yu 3 3, SH I Q ian and SH I Q i2zhen (D ep artm ent of Chem istry, N orthw est U niversity, X i an , P. R. Ch ina) GAO Y i2ci (D ep artm ent of Chem istry, L anz hou U niversity, L anz hou , P. R. Ch ina) ZHOU Zhong2yuan (Cheng d u Institu te of O rg anic Chem istry, Ch inese A cad em y of S ciences, Cheng d u , P. R. Ch ina) (R eceived N ov. 30, 1998) Tw o comp lexes of Α2m ethacrylate copper (g ) w ith im idazo le, Cu [CH 2 C (CH 3)COO ]2 ( imh ) 2 (1) and Cu2 [CH 2 C (CH 3)COO ]4 (imh ) 2 (2) w ere p repared and characterized. T he single crystal X2ray diffraction study of comp lex 1 show ed that the copper (g ) atom in the symm etric centre of the square p lanar environm ent w as coo rdinated by tw o m onodentate Α2m ethacrylate group s and tw o im idazo le ligands that w ere in trans po sition w ith each o theṙ Each mo lecular unit is linked w ith fou r neighbou ring un its by m ean s of hydrogen bond in teraction s, fo rm ing a tw o2 dim ensional supermo lecular compound (dn O = nm ). Comp lex 1 crystallizes in monoclinic, space group P 21gn w ith a= (12) nm, b= (8) nm, c= (10) nm, Β= (7), Z = 2. T he fo rm ing m echanism of the comp lexes w as discussed. Ke yw o rds Copper (g ) Α2m ethacrylate, Im idazo le, C rystal structure, Fo rm ing m echanism In troduction Copper ( g ) comp lexes w ith o rgan ic acids and o ther dono r ligands ex ist ex ten sively w ith in hum an bodies, and p lay an impo rtan t ro le in a vast range of chem ical and b iochem ical catalytic system s [1 ]. M uch atten tion has been paid to w hat they m ay reveal to the structu res and the p robab le reaction m echan ism of m etalloenzym es [2 ]. N um erou s papers dealing w ith carboxylate copper (g ) comp lexes have been pub lished. M o st of tho se comp lexes show a b inuclear cage structu re w ith b ridging Λ22carboxylate2O, O group s [3 8 ], and little is know n abou t o ther configu ration s. T he p resen t paper repo rts the syn theses and characterization of tw o Α2m ethacrylate copper ( g ) comp lexes w ith im idazo le, the purp le one being b is ( Α2 m ethacrylate ) 2b is ( im idazo le ) copper ( g ) ( 1 ) and the green one being tetrak is ( Λ22Α2 m ethacrylate2o, O ) 2b is ( im dazo le ) 2dicopper ( g ) ( 2 ). T he X2ray structu re analysis of 3 Suppo rted by the N ational N atural Science Foundation of Ch ina and the Foundation of the State Key L abo rato ry of Coo rdination Chem istry of N ajing U niversity. 3 3 To w hom co rrespondence should be addressed.

2 244 Chem ical R esearch in Ch inese U niversities V o l. 15 comp lex 1 has show n that the copper (g ) atom has a square p lanar configu ration and the mononuclear mo lecu lar un its are linked w ith hydrogen bonds, fo rm ing a tw o2dim en tional supermo lecu lar structu re. A s w e know, th is is the first examp le of mononuclear p lanar copper ( g ) comp lex w ith monoden tate coo rdinated carboxylate group s. T he fo rm ing m echan ism of the comp lexes is also repo rted. 1 Prepara tion 1. 1 Cu2 [CH2 C (CH3)COO ]4 (H2O ) 2 Exper im en tal T he m ix tu re of Cu2 (OH ) 2CO 3 (410 g) and CH 2 C (CH 3) COOH (10 ml ) in CH 3OH so lu tion w as w arm ed, stirred and refluxed fo r 5 h, then filtered under the w arm condition. A fter evapo ration of the filtrate at room temperatu re fo r several days, a b lue2green crystal of Cu2 [CH 2 C (CH 3)COO ]4 (H 2O ) 2 w as ob tain ted (yield 8715% ). A nal. Calc. (% ) : C 38116, H 4181, Cu 25124; found (% ) : C 38133, H 4180, Cu Cu[CH2 C (CH3)COO ]2 ( im H) 2 (1) and Cu2 [CH2 C (CH3)COO ]4 ( im H) 2 (2) T he m ix tu re of Cu2 [CH 2 C (CH 3)COO ]4 (H 2O ) 2 (0150 g, 1 mmo l) and im idazo le (0114 g, 2 mmo l) w as disso lved in CH 3OH (30 ml ), and stirred fo r 3 h to give a clear so lu tion. A fter evaperation of the resu lted so lu tion at room temperatu re fo r several days, purp le and green crystals w ere p roduced sim u ltaneou sly and p icked ou t respectively. Fo r the purp le com p lex C14 H 18 CuN 4O 4 ( yield 3412% ), ana l. ca lcd. (% ) : C 45146, H 4190, N 15115, Cu 17118; found (% ) : C 45137, H 4175, N 15128, Cu Fo r the g reen com p lex C22H 28Cu2N 4O 8 ( yield 4113% ), ana l. ca lcd. (% ) : C 43178, H 4168, N 9128, Cu 21105; found (% ) : C 43165, H 4171, N 9115, Cu Crysta llography A purp le crystal w ith app rox im ate dim en sion s 0136 mm 0134 mm 0126 mm of comp lex 1 w as moun ted on a Siem en s P4 diffractom eter w ith the graph ite2monoch rom ated M o K Α radiation (Κ= nm ). T he data w ere co llected w ith the Ξ22Η scan techn ique (2127 Η ) by the XSCAN S p rogram. A to tal of reflection s w ere co llected (1 124 un ique data, R int = ). L P co rrection s and ab so rp tion co rrection w ere app lied ( tran sm ission facto rs: and 01846). T he structu re w as so lved by direct m ethods and refined w ith fu ll2m atrix least2squares techn ique. T he non2hydrogen atom s w ere located w ith d ifference Fou rier syn thesis, and the hyd rogen a tom s w ere genera ted geom et rica lly. final least2squares u sing the w eigh ting schem e w = 1g[ Ρ 2 (F 2 0) + ( P ) P ], w here P = (F F 2 c) g3, converged at R F, R W and S values of , and fo r 116 param eters and ob served data w ith I > 2Ρ ( I ). coo rdinates and therm al param eters are given in T ab le 1. perfo rm ed on a IBM 486gPC u sing Siem en s SH EL XTL 2PC p rogram. T he T he non2hydrogen atom ic A ll of the calcu lation s w ere C rystal data fo r comp lex 1: C 14 H 18 CuN 4O 4, M r = , monoclin ic, space group P 21gn, a= (12) nm, b= (8) nm, c= (10) nm, Β= (7), V = (2) nm 3, Z = 2, D c= ggcm 3, Λ= cm - 1, F (000) = 382, T = 293 K.

3 N o. 3 WAN G Yao2yu, SH IQ ian, SH IQ i2zhen et al. 245 T able 1 A tom ic coo rdinates and therm al param eters fo r Cu [CH 2 C (CH 3)COO ]2 (imh ) 2 A tom x y z 10-5 U eq A tom x y z 10-5 U eq Cu (1) C (1) (1) (1) 41 (1) O (1) (1) (1) 44 (1) C (1) (1) (1) 81 (1) O (1) (1) (1) 51 (1) C (1) (1) (1) 64 (1) N (1) (1) (1) 42 (1) C (1) (1) (1) 49 (1) N (1) (1) (1) 53 (1) C (1) (1) (1) 57 (1) C (1) (1) (1) 32 (1) C (1) (1) (1) 50 (1) 1 IR Spectra Results and D iscuss ion Since the ca rboxyla te g roup can coo rd ina te to the m eta l ion in a b iden ta te o r monoden tate fash ion, the criterion, w h ich is based on the difference betw een the Μas (COO - ) and Μsym (COO - ) values compared to the co rresponding value in sodium carboxylate, has cu rren tly been emp loyed to determ ine the coo rdinating mode of carboxylate group in the ab sence of defin itive structu re data [9, 10 ]. T he data in T ab le 2 suggests that Α2m ethacrylate group s in comp lex 2 behave as b ridging b iden tate ligands betw een tw o copper (g ) atom s, cau sing a b inuclear cage structu re [8, 11 ], bu t they appear to be monoden tate in comp lex 1 [11, 12 ]. T h is conclu sion is confirm ed by the resu lt of the crystal structu ral analysiṡ T able 2 Impo rtant IR abso rp tion bands of the compouds (KB r disk) Compound Μ π as (COO - ) gcm - 1 Μ π sym (COO - ) gcm - 1 Μ π gcm - 1 Μ π (Cu N ) gcm - 1 CH 2= C (CH 3)COON a Cu2[CH 2= C (CH 3)COO ]4 (H 2O ) Cu [CH 2= C (CH 3)COO ]2 (imh ) Cu2[CH 2= C (CH 3)COO ]4 (imh ) Cu [CH 2= C (CH 3)COO ]2 (benzimh ) Cu2[CH 2= C (CH 3)COO ]4 (benzimh ) U npublicated wo rk. 2 Crysta l Structure of Com plex 1 T he selected bond distances and angles of comp lex 1 are listed in T ab le 3. pack ing diagram and the OR T EP draw ing are given in F igu res 1 and 2. T able 3 Selected bond distances (nm ) and angles ( ) 3 T he crystal Cu1 O (7) Cu1 O 1A (7) Cu1 N 1A (8) Cu1 N (8) O 1 C (11) O 2 C (9) N 1 C (12) N 1 C (2) N 2 C (13) N 2 C (14) C1 C (14) C2 C (13) C2 C (2) C6 C (2) O 2 N O 1 Cu1 O 1A O 1 Cu1 N 1A (3) O 1A Cu1 N 1A (3) O 1 Cu1 N (3) O 1A Cu1 N (3) N 1A Cu1 N C1 O 1 Cu (5) C5 N 1 C (8) C5 N 1 Cu (7) C7 N 1 Cu (7) C5 N 2 C (8) O 2 C1 O (9) O 2 C1 C (9) O 1 C1 C (7) C3 C2 C (11) C3 C2 C (10) C4 C2 C (7) N 1 C5 N (9) C7 C6 N (10) C6 C7 N (10) 3 Symm etry code: - x, - y, - z. 3 3 A djacent mo lecule uniṫ

4 246 Chem ical R esearch in Ch inese U niversities V o l. 15 F ig. 1 C rystal pack ing fo r Cu [CH 2= C (CH 3) F ig. 2 OR T EP draw ing of Cu [CH 2= C (CH 3) COO ]2 (imh ) 2 in the cell. COO ]2 (imh ) 2. T he crystal structu re show s that comp lex 1 has a mononuclear un it w ith a trans square p lanar configu ration, in w h ich the copper ( g ) atom is coo rdinated by tw o monoden tate Α2m ethacrylate group s and tw o im idazo le mo lecu les th rough non2h 2bonded n itrogen atom. T he distances of bo th Cu1 O 1 and Cu1 O 1A are all (7) nm, longer than the average Cu O ( carboxyl) distance ( nm ) of the mononuclear square pyram idal comp lex Cu [CH 2 C (CH 3) COO ]2 (b ipy) (H 2O ) [13 ]. It is sho rter than the average Cu O (carboxyl) distance ( nm ), w h ich w as found in the b inuclear cage structu re comp lex Cu2 (CH 2 CHCOO ) 4 (u rea) 2 [3 ], due to the larger charge den sity in the oxygen atom of monoden tate carboxylate group compared w ith that of b ridging carboxylate group, w h ich increases the in teraction betw een the po sitive copper and the negative oxygen atom ṡ distances of Cu1 N 1 and Cu1 N 1A are all (8) nm, sho rter than the average Cu N distance ( nm ) in Cu [ CH 2 C (CH 3 ) COO ]2 ( b ipy ) (H 2O ). T he angles of O 1 Cu1 N 1, O 1 Cu1 N 1A, O 1A Cu1 N 1A T he and O 1A Cu1 N 1 are ( 3), (3), (3) and (3) respectively, and the average angle is ; the angles of O 1 Cu1 O 1A and N 1 Cu1 N 1A are all ; tho se of C7 N 1 Cu1 and C5 N 1 Cu1 are (7) and (7) ; and that of C1 O 1 Cu1 is (5). T he cen tral copper (g ) atom is located comp letely in p lane 1 defined by the O 1, O 1A, N 1 and N 1A atom s ( deviation ). T he dihedral angle betw een p lane 1 and the im idazo le ring p lane (deviation , p lane 2) is 2015, and it is 9411 betw een the p lane 1 and p lane 3 compo sed of the O 1, O 2, C1 and C2 atom s (deviation ). angle is 9117 betw een p lane 2 and p lane 3. A num ber of in ter2hydrogen bonds ex ist in the crystal. T he dihedral Each mo lecu lar un it is linked w ith fou r adjacen t un its by hydrogen bonds, O 2 N 2B 3, O 2A N 2C 3, N 2 O 2D 3, and N 2A O 2E 3 (N 2B 3, N 2C 3, O 2D 3 and O 2E 3 belong to the fou r adjacen t un its respectively), fo rm ing a tw o2dim en sional supermo lecu lar compound ( see F ig. 1 ). hydrogen bond is nm. 3 Form ing M echan ism of the Com plexes T he distance of the It is believed from the Μin T ab le 2 that the b lue2green copper (g ) Α2m ethacrylate is a

5 N o. 3 WAN G Yao2yu, SH IQ ian, SH IQ i2zhen et al. 247 dim er w ith a b inuclear cage structu re (g ), w h ich is sim ilar to the dim eric copper (g ) acetate monohydrate [8 ]. W hen it reacts w ith im idazo le, bo th the purp le mononuclear comp lex and the green b inuclear comp lex are fo rm ed in m ethonal. A m echan ism fo r the comp lex2fo rm ing reaction s is ou tlined in Schem e 1. Schem e 1 P ropo sed m echanism fo r the fo rm ation of the comp lexes (A = carboxylate, L = im idazo le). In the reversib le step, the b inuclear cage structu re comp lex Cu2A 4 (H 2O ) 2 disaggregates partly and fo rm s mononuclear comp lex CuA 2 (H 2O ) 2 in the m ethano l so lu tion, and the structu re of the latter is less stab le compared w ith the fo rm er. T he coo rdinated H 2O mo lecu les of the tw o species w ou ld be disp laced by L w hen ano ther stronger dono r ligand L is added to the so lu tion. T he dono r ligands added m ay be classified in tw o typeṡ L igands such as u rea [3 ], an tipyrine, acetam ide [14 ] and H 2O itself are disadvan tageou s to stab ilize the square p lanar structu re. T he m ain p roduct of the reaction is b inuclear comp lexeṡ L igands such as im idazo le and benzim idazo le (see T ab le 2) stab ilize bo th the square p lanar structu re and the b inuclear structu re, fo rm ing tw o comp lexes sim u ltaneou sly in the reaction. Re fe re nce s [ 1 ] K ing, R. B., Encyclopedia of Ino rganic Chem istry, John W iley & Sons, N ew Yo rk, 1994, 829 [ 2 ] Ho lm, R. H., Kennepoh l P. and So lomon, E. İ, Chem. R ev., 96, (1996) [ 3 ] W ang Yao2yu, Sh i Q ian, Sh i Q i2zhen et al., Ch inese Science Bulletin, 43 (23), (1998) [ 4 ] M elnik, M., Kom an, M., M acaskova, L. et al., J. Coo rd. Chem., 43, 159 (1998) [ 5 ] L eban, İ, Grgurevic, N., Sieler, J. et al., A cta C rysṫ, C53, 854 (1997) [ 6 ] Kato, M. and M uto, Y., Coo rd. Chem. R ev., 92, 45 (1988) [ 7 ] M elnik, M., Coo rd. Chem. R ev., 42, 259 (1982) [ 8 ] N iekerk, J. N. V an. and Schoening, F. R. L., A cta C rysṫ, 6, 227 (1953) [ 9 ] Catterick, J. and T ho rnton, P., A dv. Ino rg. Chem. R adiochem, 20, 291 (1977) [10 ] D h indsa, A. S., T hesis of Ph. D., Punjabi U niversity, Patiala, India, 1983 [11 ] M usum eci, S., R izzarelli, E., Samm artano, S. et al., Z. A no rg. A llg. Chem., 433, 297 (1977) [12 ] WAN G Yao2yu, GAO Yao2ci and SH IQ i2zhen, Chem. J. Ch inese U niversities, 18, 348 (1997) [13 ] GAO Yao2ci, WAN G Yao2yu and SH IQ i2zhen, Po lyhderon, 16, (1991) [14 ] SH IQ ian, WAN G Yao2yu, TAN G Zong2xun et al., Ch inese J. Strucṫ Chem., 18 (1), 24 (1999)

Syn thesis and Crysta l Structure of Neodym ium Com plex w ith Glyc ine [Nd (Gly) (H2O ) 7 ]Cl3

V o l. 15 N o. 4 1 9 9 9 Chem ical R esearch in Ch inese U niversities 306 310 Syn thesis and Crysta l Structure of Neodym ium Com plex w ith Glyc ine [Nd (Gly) (H2O ) 7 ]Cl3 L I Jun2ran 3 3, ZHOU L i2p