Synthesis and Catalytic Activity of Aluminum Complexes Supported by Bis(β-ketimine) and Bis(β-diketimine) Ligands†

doi:10.7503/cjcu20130664

Abstract

Abstract:

Owing to its special physical and chemical properties as well as good coordination activity with transition metals, β-diketone-derived β-ketimines and β-diketimines have been extensively studied in recent years. In this work, five new bridged bis(β-ketimine)(1—5) and bis(β-diketimine) ligands(6,7) were synthesized by the condensation reaction of 3,3'-(1,4-phenylene)bis(2,4-pentanedione) with various anilines. Treatment of these ligands with AlMe₃ afforded five new aluminum complexes(8—12). All these compounds were characterized via elemental analysis, ¹H NMR, ¹³C NMR, ESI-MS and IR spectroscopy. Structures of two aluminium complexes were determined by the X-ray single-crystal diffraction analysis. The bridged β-ketimine acted as a chelating N, O-bidentate ligand to the aluminium atom. Each aluminum atom showed a distorted tetrahedral coordination geometry. These aluminum complexes exhibited effective catalytic activity in the ring-opening polymerization of ε-caprolactone.

Key words: Bridged bis(β-ketimine), Bridged bis(β-diketimine), Aluminum, Crystal structure, Catalytic activity

CLC Number:

O627

TrendMD:

HUANG Qingdong, LI Chunlan, ZHANG Yu, CUI Lishan, ZHU Baichun, YI Jianjun, LIU Lin, HAO Haijun. Synthesis and Catalytic Activity of Aluminum Complexes Supported by Bis(β-ketimine) and Bis(β-diketimine) Ligands^†[J]. Chem. J. Chinese Universities, 2014, 35(3): 524.

Figures/Tables 5

Scheme 1 Synthetic routes of bis(β-ketimine)s and bis(β-diketimine)s as well as their aluminium complexes

Table 1 Crystal data and refinement parameters for complexes 8 and 10

Complex	8	10
Formula	C₃₆H₄₆Al₂N₂O₂	C₃₈H₅₀Al₂N₂O₂
Formula weight	592.71	620.76
Crystal size	0.64 mm×0.58 mm×0.18 mm	0.43 mm×0.30 mm×0.20 mm
Crystal system	Triclinic	Triclinic
Space group	P $1 ˉ$	P $1 ˉ$
a/nm	0.7733(2)	0.8151(2)
b/nm	0.8122(2)	0.8181(3)
c/nm	1.5506(4)	1.5797(4)
α/(°)	77.693(8)	95.53(2)
β/(°)	80.114(8)	97.33(1)
γ/(°)	64.744(6)	116.814(8)
V/nm³	0.8569(3)	0.9182(4)
Z	1	1
D_c/(g·cm^-3)	1.149	1.123
F(000)	318	334
μ/mm^-1	0.117	0.112
θ Range/(°)	2.70—29.99	2.83—29.00
No. of measured reflections	10177	11055
No. of unique reflections(R_int)	4873(0.0261)	4811(0.0325)
No. of observed reflections([I>2σ(I)])	3930	3738
No. of parameters	196	205
GOF	1.0001	1.003
R₁, wR₂ [I>2σ(I)]	0.0449, 0.1143	0.0627, 0.1274

Table 1 Crystal data and refinement parameters for complexes 8 and 10

Complex	8	10
Formula	C₃₆H₄₆Al₂N₂O₂	C₃₈H₅₀Al₂N₂O₂
Formula weight	592.71	620.76
Crystal size	0.64 mm×0.58 mm×0.18 mm	0.43 mm×0.30 mm×0.20 mm
Crystal system	Triclinic	Triclinic
Space group	P $1 ˉ$	P $1 ˉ$
a/nm	0.7733(2)	0.8151(2)
b/nm	0.8122(2)	0.8181(3)
c/nm	1.5506(4)	1.5797(4)
α/(°)	77.693(8)	95.53(2)
β/(°)	80.114(8)	97.33(1)
γ/(°)	64.744(6)	116.814(8)
V/nm³	0.8569(3)	0.9182(4)
Z	1	1
D_c/(g·cm^-3)	1.149	1.123
F(000)	318	334
μ/mm^-1	0.117	0.112
θ Range/(°)	2.70—29.99	2.83—29.00
No. of measured reflections	10177	11055
No. of unique reflections(R_int)	4873(0.0261)	4811(0.0325)
No. of observed reflections([I>2σ(I)])	3930	3738
No. of parameters	196	205
GOF	1.0001	1.003
R₁, wR₂ [I>2σ(I)]	0.0449, 0.1143	0.0627, 0.1274

Fig.1 Molecular structures of complexes 8(A) and 10(B)Symmetry operation: -x, -y, -z.

Table 2 Selected bond lengths(nm) and bond angles(°) for complexes 8 and 10

Complex 8		Complex 10
Al1—O1	0.1796(1)	Al1—O1	0.1797(1)
Al1—N1	0.1940(1)	Al1—N1	0.1944(1)
C9—O1	0.1310(1)	C9—O1	0.1310(2)
C7—N1	0.1319(1)	C7—N1	0.1322(2)
C7—C8	0.1448(2)	C7—C8	0.1447(2)
C8—C9	0.1379(2)	C8—C9	0.1380(2)
C17—Al1—C18	115.42(8)	C18—Al1—C19	115.03(9)
N1—Al1—O1	93.72(4)	N1—Al1—O1	93.29(5)
N1—Al1—C18	112.43(7)	N1—Al1—C18	112.28(7)
Al1—O1—C9	127.46(8)	Al1—O1—C9	126.3(1)
Al1—N1—C7	124.49(9)	Al1—N1—C7	124.09(9)
C6—N1—C7	120.2(1)	C1—N1—C7	119.4(1)
O1—C9—C8	124.3(1)	O1—C9—C8	124.3(1)
C7—C8—C9	123.4(1)	C7—C8—C9	123.0(1)
C8—C7—N1	122.3(1)	C8—C7—N1	122.3(1)

Table 3 Ring-opening of polymerization of ε-caprolactone initiated by complexes 8—10*

Entry	Catalyst	ε-Caprolactone/g	Temp./℃	M_n	PDI	Yield(%)
1	8	7.70	60	26736	1.94	85
2	8	7.70	100	21438	1.76	93
3	9	6.30	60	36771	1.89	89
4	9	6.30	100	23974	1.61	92
5	10	7.30	60	23120	1.91	91
6	10	7.30	100	22976	1.70	95

References 22

[1]	Yu R. C., Hung C. H., Huang J. H., Inorg. Chem., 2002, 41, 6450—6455
[2]	He X., Yao Y., Luo X., Zhang J., Liu Y., Zhang L., Wu Q., Organometallics,2003, 22, 4952—4957
[3]	Zhang L., Brookhart M., White P. S., Organometallics,2006, 25, 1868—1874
[4]	Song P. D., Ye W. P., Wang Y. X., Li Y. S., Organometallics,2009, 28, 5697—5704
[5]	Lyashenko G., Saischek G., Pal A., Herbst-Irmer R., Moesch-Nanetti N.C.,Chem. Commun., 2007, 701—703
[6]	Hao H., Cui C., Roesky H.W., Bai G., Schmidt H. G., Noltemeyer M.,Chem. Commun., 2001, 1118—1119
[7]	Cui C., Roesky H., Schmidt H.G., Noltemeyer M., Hao H., Cimpoesu F., Angew. Chem. Int. Ed., 2000, 39, 4274—4276
[8]	Bourget-Merle L., Lappert M. F., Severn J. R., Chem. Rev., 2002, 102, 3031—3065
[9]	Bai G., Peng Y., Roesky H. W., Li J., Schmidt H. G., Noltemeyer M., Angew. Chem. Int. Ed., 2003, 42, 1132—1135
[10]	Bai G., Wei P., Das A.K., Stephan D. W.,Dalton Trans., 2006, 1141—1146
[11]	Neculai D., Roesky H. W., Neculai A. M., Magull J., Schmidt H. G., Noltemeyer M., J. Organomet. Chem., 2002, 643/644, 47—52
[12]	Dove A.P., Gibson V. C., Marshall E. L., White A. J. P., Williams D. J.,Dalton Trans., 2004, 570—578
[13]	Hao H. J., Han X. M., Synthesis and Application of Carbon-linked Bis(β-ketiminato)aluminum Complexes CN 101302230,2008-11-12
	(郝海军, 韩秀敏. 碳桥联双酮单亚胺基铝配合物的合成及应用, CN 101302230, 2008-11-12)
[14]	Zhang F.L., Synthesis and Structural Characterization of Aluminum, Zinc, and Nickel Complexs Derived from the Novel Linked β-Bis(diketimine) Ligands, Beijing University of Chemical Tecnology, Beijing, 2006
	(张发良. 碳桥联双β-酮二亚胺基铝、锌和镍配合物及碳桥联双β-酮二亚胺二氯化镍配合物的合成和结构表征, 北京: 北京化工大学, 2006)
[15]	Ramirez F., Bhatia S. B., Patwardhan A. V., Smith C. P., J. Org. Chem., 1967, 32, 3547—3553
[16]	Lambert J. B., Liu Z., J. Chem. Crystallogr., 2007, 37, 629—639
[17]	Sheldrick G.M., SHELXS-97, Prgram for X-Ray Crystal Structure Solution, Göttingen University, Göttingen, 1997
[18]	Sheldrick G.M., SHELXL-97, Prgram for X-Ray Crystal Structure Refinement, Göttingen University, Göttingen, 1997
[19]	Neculai D., Neculai A. M., Roesky H. W., Magull J., Bunkòczi G., J. Fluorine Chem., 2002, 118, 131—134
[20]	Gong S., Ma H.,Dalton Trans., 2008, 3345—3357
[21]	Koiwa T., Masuda Y., Shono J., Kawamoto Y., Hoshino Y., Hashimoto T., Natarajan K., Shimizu K., Inorg. Chem., 2004, 43, 6215—5223
[22]	Ma B., Djurovich P. I., Yousufuddin M., Bau R., Thompson M. E., J. Phys. Chem. C,2008, 112, 8022—8031