X-Ray Diffraction Powder Data for Some Copper N-AIkylsalicylaldimine Chelates ROBERT G. CHARLES and
W. D. JOHNSTON
Wesfinghouse Research laboratories, Churchill Borough, Pittsburgh 35, Pa.
b X-ray diffraction powder data are presented for 1 1 copper chelates derived from straight-chain primary amines. The data permit identification of unsubstituted straight-chain primary amines containing from one to 14 carbon atoms.
C
and nickel chelates of Type 1 have been suggested as suitable derivatives for characterizing the primary amines RSH2 ( 2 ) . This paper reports diffraction powder data for 11 such copper chelates. The patterns obtained are distinctive and provide a means of positively identifying the amines from which the chelates are OPPER
R
derived. The copper chelates appear to be particularly suitable derivatives for characterization, as they are readily prepared and purified, are stable and nonhydroscopic, and give sharp diffraction patterns. The data obtained are listed in Table I. Equally distinctive patterns were obtained for the corresponding nickel compounds. The latter should also be suitable for amine identification purposes b u t offer no advantage over those for the copper compounds. For this reason, in addition to the fact t h a t the copper compounds are somewhat easier to recrystallize, data for the nickel chelates are not presented. It is perhaps surprising that no significant similarities were observed among the patterns obtained within either the copper or nickel series. Apparently a difference in length of one -CH2group in the amine chain is sufficient to alter significantly the crystal structure. I n most cases the patterns of the corresponding nickel and copper chelates are dissimilar. However, when R (Formula 1) is butyl, amyl, or heptyl, chelation with either copper or nickel gives products having nearly identical patterns. For the butyl and heptyl
Table 1.
X-Ray Diffraction Powder Data for Copper(lll N-Alkylsalicylaldimine Chelates
[Headings indicate the alkyl group ( R in Formula 1)i d, A . 1/11 d, A. 1/11 d, A. 1/11 d, -4. 1/11 Methyl Ethyl (Contd.) . n-Propyl (Contd.) n-Amvl 14.65 12.14 9.50 8.58 7.99 6.07 5.36 4.91 4.56 4.30 4.03 3.88 3.67 3.31 3.19 3.10 3.05 2.99 2.91 2.60 2.54 2.46 2.33 2.30 2.24 2.15 2.10 2.06 2.03 2.00 1.97 1.92 1.90 1.87 1.84 1.80 1.74 1.72 1.68 1.66 1.63 1.61 1.53 1.48 145 1.40
0.5 1.0 0.1 1.0 0.1 0 6 0.1 0.8 0.1 0.6 0.6 0.1 0.3 0.9 0.8 0.8 0.8 0.1 0.2 0.4 0.4 0.2 0.1 0.3 0.4 0.4 0.1 0.3 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.2 0.1 0.2 0.2 0.2 0.2 0.1 0 2 0.2
Ethyl 10.37 9.65 7.82 6.35 5.87 5.35 5.12 4.99 4.79 4.40 4.29 4.16 3.87
0.6 0.1 1.0 1.0 1.0 0.2 0.6 0.4 0.4 0.2 0.6 0.8 0.4
3.73 3.66 3 49 3.22 3.08 3.04 2.89 2.83 2.75 2.70 2.64 2.58 2.53 2.48 2.45 2.42 2.18 2.12 2.08 2.04 2.01 1.05
0.8 0.2 0.4 0.6 0.6 0.2 0.2 0.1 0.1 0.~ .2 0.2 0.2 0.2 0.2 0.2
1.84 181 1.78 173 1.71 168 1.66
0 2
0 2 0 1 0 1 0 2 0 2 0.1
n-Butyl
9.47 7.20 6.40 6.04 5.81 5.28 0.1 5.14 0.i 4.80 0.2 4.36 0.2 4.27 0.4 3.78 0.2 3.69 0.3 3.62 3.53 n-Propyl 3.47 9.07 1.0 3.27 7.17 0.9 3.19 6.54 0.9 3.03 5.74 0.3 2.91 5.01 0.5 2.82 4.68 0.2 2.78 4.5Y 0.6 2.73 4.35 0.6 2.66 4,Ol 0.1 2.63 3.71 1.0 2.59 3.57 0.4 2.55 3.44 0.2 2.50 3.31 0.4 2.45 3.12 0.3 2.41 3.00 0.8 2.32 2.94 0.4 2.29 2.87 0.2 2.19 0 2 2.63 2.15 2.61 0.1 2.13 2.56 0.3 2.10 2.51 0.2 2.02 2.48 0.1 1.97 2.38 0.2 1.94 2.34 0.2 1.89 2.29 0.2 1.84 2.24 0.2 1.82 2.20 0.1 1.80 2.16 0.3 1.77 1.75 1.71 1.69 1.66 1.64 1.63 1.59 1.88 0.2 1.58 1.86 0.2 12.11 (Continued on page 11.46)
10 0.2 0.8 0.4 0.2 0.1 0.1 1.0 0.4 0.3 0.8 0.3 0.3
0.2 0.2 0.3 0.8 0.6 0.1 0 6 0.2 0.2 0.1 0.1 0.4 0.2 0.2 0.2 0.4 0.1 0.1 0.1 0.2 0.3 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 0.2 0.2 0.1 0.2 1.0
5.06 4.56 4.35 4.24 4.06 3.95 3.80 3.62 3.42
0.2 0.9 0.1 0.4 0.8 0.7 0.6 0.1 0.1
2.62
0.2
2.21 2.17 2.14 1.97
0.2 0.2 0.2 0.4
n-Hexyl 13.55 7.90 6.77 6.46 5.62 5.22 4.88 4.74 4.60
1.0 0.1
2.84 2.77 2.72
0.1
VOL. 2 9 , NO. 8, AUGUST 1957
1.0
i.0 0.9 1.0 0.6 0.6 0.1
0.1 0.1
1145
~
Table I.
X-Ray Diffraction Powder Data for Copper(l1) N-Alkylsalicylaldimine Chelates (Continued) [Headings indicate the alkyl group (R in Formula l ) ]
d, A .
1/11
n-Hexyl ___(Contd.)
.
2.67 2.61 2.52 2.44 2.40 2.37 2.30 2.26 2.21 2.17 2.14 2.12 2.07 2.03 1.98 1.91 1.87 1.84 1.81 1.78 1.75 1.70 1.68 1.65 1.61 1.58 1.56 1.53 1.51 1.47 1, 4 4 1.42 1.38 1.36
0.1 0.6 0.5 0.4 0.5 0.4 0.4 0.5 0.1 0.4 0.4 0 2 0.1 0.5 0.1 0 5 0 6 0 1 0 2 0 2 0 2 0 1 0 2 0 1 0 2 0 2 0 2 0 1 0 1 0 1 0.2 0.2 0.1 0.2
I/Ii n-Heptyl
d, A.
14.04 8.51 7.96 7.01 5.97 5.30 5.04 4.86 4.65 4.56 4.45 4 31 4 06 3 96 3 66 3 48 3 38 3 23 2 81 2 62 2 53 2 48 2 13 2 32 2 27 223 220 217 208 2 04 1.98 1.91 1.88
1.0 0.7 0.7 0.6 0.5 0.1 0.8 0.1 0.6 0.2 0.6 0.8 0.8 0.6 0.8 0.2 0.2 0.8 0.4 0.1 0.2 0.1 0.1 0.1 0.1 0 1 0 2 0 2 0 2 0.2 0.2 0.1 0.1
compounds somewhat smaller interplanar spacings were found for the nickel chelates compared with the corresponding copper chelates; the amyl chelates of nickel and copper show little difference in spacing. The copper and nickel N-methylsalicylaldimine chelates have different patterns. Stackelberg (4) has concluded, on the basis of single crystal diffraction data, t h a t the configuration about the copper in the former compound is planar and trans. Magnetic measurements on the corresponding nickel chelate (1,5) suggest t h a t the configuration about the nickel atom is also planar. I n view of these facts, and the similarity of ionic radii of these metal ions, one might expect similar crystal structures. KO similarities are, however, observed. EXPERIMENTAL
Chelate Preparation. T h e copper and nickel chelates were prepared by modifications of existing methods ( 3 ) . I n a typical preparation 0.05 mole of salicylaldehyde was mixed with 0.05 mole of t h e amine in 100 ml. of methanol. T o t h e resulting solution was added 0.025 mole of copper acetate or nickel acetate in 100 ml. of water, followed by a solution of 5 grams of sodium acetate in 50 ml. of water. T h e mixture was heated 1146
ANALYTICAL CHEMISTRY
d, A .
I ‘I]
1/11
n-Decyl
n-Octyl 16.08 8.06 6.67 6.48 6.16 5.83 5.51 4.77 4.64 4.46 4.21 4.09 3.94 3.85 3.62 3.54 3.30 3.10 3.05 2.98 2.92 2.82 2.59 2.42 2.36 2 26 2 23 2 19 2 15 2.12 2.03 1.99 1.97 1.93
d , A.
1.0 0.8 0.2 0.8 0.5 0.5 0.8 0.5 0.6 0.6 0.: 0. I 0.7 0.2 0.2 0.8 0.7 0.2 0.1 0.1 0.2 0.6 0.2 0.2 0.2 0.1 0.2 0.1 0.1 0.1 0.2 0.2 0.2 0.2
17.77 9.37 6.67 6.05 5.85 5.25 5.10 4.95 4.86 4.71 4.30 4.19 4 . I1 3.80 3.67 3.49 3.44 3.24 3.06
2.97 2.86 2.82 2.68 2.64 2.55 2.4i 2.41 2.35 2.31 2.26 2.15
d, A.
Ill1
n-Dodecyl 0.8 1.0 0.9 0.~ .2 0.8 0.2 0.2 0.6 0.5 0.8
20.68 10.66 7.07 6.61 6.15 5.99 5.69 5.34 5.18 4.82
0.4 0.6 0.4 0.1 0.4 0.1 0.1 0.1 0.1
3.82 3.55 3.42 3.37 3.31 3.24 3.17 3.08 3.03
briefly and cooled, and the crystalline chelate was filtered off. The compounds were, in all cases, recrystallized from methanol. More detailed information regarding t h e preparation, as well as t h e appearance and melting points of t h e chelates used here, is given elsewhere (2). Some of these materials map exist in more than one crystalline form. Care must therefore be taken in comparing the data given here with those obtained for chelates recrystallized from solvents other than methanol. No evidence of polymorphism was observed for any of the copper chelates studied when they were recrystallized from methanol. Bis-N-methplsalicylaldimine nickel(I1) was obtained as a mixture of needles and plates from the latter solvent. Both forms, however, gave the same pattern. The other nickel chelates studied yielded only a single crystalline form. X-Ray Measurements. Specimens were prepared by grinding samples t o 200 mesh a n d loosely filling glass capillaries 0.3 mm. i n diameter. About 0.5 mg. of chelate was required. All patterns were obtained using a North American Phillips Debye camera 11.54 em. in diameter. Cobalt radiation was employed with XKa taken as l.79021 A. All exposures
2.14 2.09
1.0 1.0 0.6 0.8 0.2 0.7 0.4 0.4 0.7 0.4 0.8 0.4 0.8 0.5 0.5 0.3 0.8 0.6 0.6 0.1 0.1 0.2 0.2 0.6 0.4 0.1 0.1 0.4 0.3 0.4 0.1 0.4 0.4
III, n-Dodecyl (Contd.) d, A.
2.04 1.82
0.1 0.2
n-Tetradecyl _.
23.64
0.6
12 21 9 39 8.78 8.18 7.31 6.59 6.13 5.22 5.01 4.85 4.65 4.41 4.28 4.19 4.07 3.96 3.80 3.72 3.55 3.35 3.11 2.99 2.88 2.76 2.65 2.52 2.41 2.31 2.19
0.1 0 4 0.6 0.5 0.5 0.6 0.2 0.2 0.1 0.1 0.8 0.6 0.7 0 1 0.2 0.2 0.3 0.4 0.4 0.4 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1
i.0
were of 24-hour duration. The technique employed permitted d values of up to about 24 A. to be measured. Intensity values in Table I are averages of values estimated visually by two independent observers. The line intensities are expressed in Table I as 1/I2,where IItaken as unity refers to the intensity of the most, dense line in each pattern. ACKNOWLEDGMENT
The writers are happy to acknowledge the help of Donald Sestrich and Dorothy Anderson, both of whom assisted in the experimental portion of this %-ark. LITERATURE CITED
(1) Basolo, F., Matoush, W. R., J . Am. Chem. Soc. 75, 5663 (1953). (2) Charles, R. G , J. Org. Chem., submitted for publication. (3) Pfieffer, P., J. prakl. Chem 153, 270 (1939). (4)Stackelberg, M., 2. anorg. allgem. Chem. 253,136 (1947). (5) Willie, J. B., Mellor, D. P., J. A m . Chem. SOC.69, 1237 (1947).
RECEIVED for review November 23, 1956. Accepted February 28, 1957.
