4.4 PROGRAMACIÓN DEL PLC
4.4.5 Cargar el programa en el PLC S7-1200
Direct addition of anhydrous C u C h and an excess of trimethylamine in a sealed double ampoule vessel provides a yellow-brown solid which, by vir tue of limited solubility in the parent amine, was extracted in situ (following filtration and back distillation of trimethylamine) to give a bright yellow solid.
Previously Lane and Yoke [25] have shown that direct treatment of anhydrous C u C i
2
with trimethylamine at o° c gives the stable yellow-brown mono adduct C u C i2
nmo (analytical values based on c u c i2
.i.obi/vm* The ini tial blue-green product is presumed as the bis adduct CuCi2.WMe3\ this changes to the yellow-brown mono adduct once all the trimethylamine has been removed. In their studies oxidation of trimethylamine by c u c i2
has been observed above 75*c, resulting in a dark red tarry product. Dimethylmethylene ammonium cation is obtained as the oxidation product of trimethylamine, but the nature of the Cu(I) reduction product is not clear.
In our studies further purification of the yellow solid via a Soxhlet extraction with boiling benzene provided a bright yellow solid with a sharp melting point 154-155° c. Micro-analytical data corresponds with the mono adduct CmCh-i iNtie, - identical with that of Lane and Yoke. The ir spectrum shows all the bands of co-ordinated trimethylamine (1265 cm1, 999 cm1, 830 cm-' and 564 cm-') and the far ir has two bands below 400 cm-1 at 250 cm ' and 204 cm-' assigned to Cu-Cl stretching modes. The electronic spectrum has a "d-d" band at 11,494 cm-' with a broad shoulder at 13,089 cm-'.
Several attempts to get this mono adduct in a crystalline form (via recrystallization from benzene, acetonitrile and other non-chlorinated sol vents) to undertake an X-ray structure determination were unsuccessful. However the use of a chlorinated solvent c h*c i2 provided golden yellow
cubic crystals suitable for X-ray structural studies. The yellow crystalline product is characterized as kCHihNCHicih [CuCU] which melts with decompo sition at 220-222° c. The ir spectrum contains bands at 1150(br,w), 970(m), 804{m), and 720(st) cm-'. The strong bands at 1265, 1000, 830 and 565 cm-' characteristic of co-ordinated trimethylamine are no longer present. The far
ir has a broad asymmetric band at 271 cm-' with evidence of a shoulder on the higher energy side at 290 cm-', characteristic of vCm-c, of the tetrachlorocuprate(II) anion. (The literature values for the vj (Cu-Cl stretch ing) for heiwmcuCU) are at 289(sh), 268(st) and 247(m) cm-' [90]; 267 cm-'
[91]; 267(st) and 248(sh) cm ' [92]). The electronic spectrum has a single broad band in the near ir region at ) u 9360 cm-'. Decomposition of the mono adduct with the formation of the novel trimethylchloromethylam- monium cation and tetrachloro cuprate(II) anion clearly must involve some sort of rearrangement with the solvent molecule c//jC/2. Dichloromethane can provide the CHtCr which rapidly combines with trimethylamine to give
the quaternary ammonium cation. The accompanying ci~ must be utilized in
the formation of the chlorocupratc(II) anions.
The anion obtained from dichloromethane is the tetrachlorocuprate(II) anion not the trichlorocuprate(II) anion. It is not clear why the tetrachloro- cuprate anion is formed in preference to the trichlorocuprate anion; perhaps the lattice energy considerations are heavily in favour of the former.
The crystal structure of [MeyNCH^ciHCuCUi (VII)
C l( 2 )
Crystal data
Formula C u C lé C tH j& t
M 422.42
Crystal class monoclinic
a 15.273(15) À b 17.493(18) À c 11.722(13) <4 0 75.8(1)®
V
1837.0 (4 )J F(000) 860 dm 1.53 gcm~3 dc 1.53 gemz
4 p (Mo-Ka) 20.8 c « - ' Space group P 2 i n Crystal size 0.3 x 0.4 x 0.2 mm Final R 0.062 = 0.064)Table 1.7 Molecular Dimensions (Distances-À, Angles-Degrees)
Dimensions in the Anion
C u ( l ) - C l ( l ) 2 .2 4 5 (4 ) C u (l)-C l(2 ) 2 .2 5 3 (3 ) C u ( l ) - a ( 3 ) 2 .2 3 2 (3 ) C u ( l ) - a ( 4 ) 2 .2 4 3 (3 ) C l( l) - C u ( l) - C l( 2 ) 132.5 2(1 5 ) C l( l) - C u ( l) - C l( 3 ) 9 9 .7 1 (1 3 ) C l( 2 )-C u (l)- C l( 3 ) 9 7 .9 8 (1 4 ) C l ( l ) - C u ( l ) - a ( 4 ) 9 9 .9 4 (1 4 ) C l( 2 )-C u (l)- C l( 4 ) 9 8 .2 1 (1 4 ) C l(3 )-C u (l)-C l(4 ) 1 34.44(16)
Dimensions in the cations
C l(1 0 )-C (1 3 ) 1.72 8(13 ) C ( l l ) - N ( 1 4 ) 1.47 8(20 ) C (1 2 )-N (1 4 ) 1.4 47(1 5) C (1 3 )-N (1 4 ) 1.4 98(1 6) C (1 5 )-N (1 4 ) 1 .575 (15) C l(2 0 )-C (2 0 ) 1.77 1(13 ) C (2 0 )-N (2 1 ) 1 .467 (14) N (2 1 )-C (2 2 ) 1 .470 (16) N (2 1 )-C (2 3 ) 1.52 4(15 ) N (2 1 )-C (2 4 ) 1.49 6(18 ) C l( 10)-C ( 13)-N ( 14) 109.9(8) C (1 1 )-N (1 4 )-C (1 2 ) 114.9(11) C (1 1 )-N (1 4 )-C (1 3 ) 109.0(10) C (1 2 )-N (1 4 )-C (1 3 ) 114.4(9) C (1 1 )-N (1 4 )-C (1 5 ) 10 7 .6(10) C (1 2 )-N (1 4 )-C (1 5 ) 107.3(11) C (1 3 )-N (1 4 )-C (1 5 ) 102.6(10) C l(2 0 )-C (2 0 )-N (2 1 ) 112.0(7) C (2 0 )-N (2 1 )-C (2 2 ) 113.1(11) C (2 0 )-N (2 1 )-C (2 3 ) 112.1 (9) C (2 2 )-N (2 1 )-C (2 3 ) 109.7(10) C (20 )-N (21 )-C (2 4 ) 104.4(8) C (22)-N (2 1 )-C (2 4 ) 109.8(11) C (2 3 )-N (2 1 )-C (2 4 ) 10 7 .6 ( 11 )
Discussion of the structure
The structure which is shown in the Figure 1.16 together with the atom
numbering scheme consists of two independent [Me^CH^cih cations and one
ICuCitp- anion. Bond lengths and bond angles are given in Table 1.7. The conformation of the cation is as expected. In the anion there is a significant deviation from both of the two ideal geometries, square planar and tetrahedral, in that the angles around the metal atom are 98.0(1), 98.2(1), 99.7(1) and 99.9(1), 132.5(1) and 134.40)*. The bond lengths are however regular at 2.232(3), 2.243(3), 2.245(4), 2.253(3) 4.
In a recent publication, Halvorson et al. [93] have analyzed over 60 crystal structure determinations containing the icuci4)2- anion. The majority of the structures contain trans Cl-Cu-Cl angles between 125 «nd 145». From a plot of trans angles against frequency, there is a maximum around 135° with a secondary maximum at iso*. Halvorson et al. [93] note that the occurrence of hydrogen bonds to the chlorine atoms in the anion tends to decrease the
trans angle.
However there are necessarily no such contacts in the present structure and indeed the closest C-H....C1 contact is 2.7 3 4. So it is perhaps appropriate that the present angles at 133.134» are almost identical to the reported
maximum at 135«.
Halvorson et al. also correlate the value of the d-d electronic absorption with the trans Cl-Cu-Cl angle and obtain a straight line plot so that with an angle of 134«, the predicted energy is 9.500 c«-'. Our experimental value is 9360 cm-' which is very close to the predicted value.