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Nitrosamine complexes of SbCl5 and CuCl2
ELSEVIER
Inorganica Chimica Acla 269 (1998) 7-12
Nitrosamine complexes of SbC15 and CuCI: Alfred Schmidpeter *, Heinrich N6th h~stitutfiir Anorganische Chemie, Ludwig-Maxbnilimzs-Universitiit. D-80333 Munich, Germany Received 17 February 1997; revised 8 April 1997; accepted 5 May 1997
Abstract Dialkylnitrosamines form !:1 complexes with SbCls (colourless) and CuCi2 (reddish brown). Me2NNOSbCis (1) crystallizes in the monoclinic space group P2,/n with a = 8.860(2), b = 13.150( 3 ), c = 9.540(2) A,/3 = 92.58 ( 3 )* and Z = 4. The components are joined by a O-Sb bond and the complex is isostructural to that of dimethylformamide Me,NCHOSbCIs. The N-nitrosopiperidine CuCI2 complex (6) crystallizes in the monoclinic space group P2,/c with a = 6.5294(2), b = ! 6.7236( 3 ), c = 8.5990(2) A,/3 = 1 ! 2.2 ! 0( i ) ° and Z = 4. As in the case of the known dimethylnitrosamine CuCI, complex (5) the structure consists of infinite doubly chlorobridged CuCi, chains to both sides of which nitrosamine molecules are coordinated both by the O atom and the N atom of their nitroso group. While the nitroso groups of the dimethylnitrosamine molecules point in the same direction at either side of the chain resulting in a uniform CuCI4ON array in $, the nitrosopiperidine molecules at the two sides of the chain are arranged in opposite directions resulting in alternating CuCI40., and CuCI4N., arrays in 6. In the latter coordination the Jahn-Teiler distortion results in an elongation of the CuN, axis, while in the former an elongation of two of the CuCI bonds is noted. © 1998 Elsevier Science S.A. Keywords: Antiunony complexes; Crystal structures; Nitrosamine complexes; Copper complexes
I. Introduction Like other acid amides and in particular like carbonic acid amides nitrosamines are ambident ligands offering an acceptor the alternative of coordination through the aminogroup nitrogen atom or through the oxygen atom. Nitrosamines have the potential to coordinate via their central nitrogen atom as a third alternative III. While initially a coordination to the aminogroup nitrogen atom had been assumed tbr the dialkylnitrosamine BF3 complexes 121, later on an O-coordination was shown for all the main group acceptors investigated. These interactions include the protonation [3-6], alkylation [ 3,7-111 and silylation [ 121 of nitrosamines as well as the addition of ZnBr2, BF3, AICI.a, PCI.~, SbCI.~, and SO~ [ 1,131 to nitrosamines. An X-ray structure analysis so far seems available only of the binitrosamine cation in 2114 i. This paper now reports the structure of the complex Me2NNOSbCI.~ (1). Also with transition metal centres, a sole O-coordination has been found for the bis(diethylnitrosamine) complex 4 of tetraphenylporphyrinatoiron (III) by X-ray structure analysis 115] and has been suggesteu Ibr bis(nitrosamine) PdCI2 complexes [161. However, O-coor* Corresponding author: Tel.: + 49 89 5902 249; fax: + 49 89 5902 578. n Dedicated to Professor Wolfgang Beck on the occasion of his 65th birthday. 0020-1693/98 / $19.00 © 1998 Elsevier Science S.A. All rights reserved Pll S 0 0 2 0 - i 693 ( 97 ) 0 5 7 6 8 - X
dination seems not to be the only interaction in nitrosamine complexes of transition metal chlorides [ I ]. This is shown in particular by an X-ray structure analysis of the dimethylnitrosamine CuCl,, complex ($) [ 17,18], which in the present paper will be compared with the somewhat deviating structure of the CuCI2 complex 6 of N-nitrosopiperidine (the corresponding CuBr2 complexes are also known [ 19] ).
2. Dimethylnitrosamine SbCI~ complex Dimethylnitrosamine forms a stable i:I complex 1 with antimony pentachloride [ 1 ]. Recrystallization fromdichloromethane yields colourless crystals suitable for X-ray structure analysis.
.,e
.,% N--N
H3C'
~
N--N
*d-s-bc,
'o-s-bc,
la
~
1b
~=N
N--N
PF~"
O--H"-C)~kN__N~ 2
A. Sehmidpeter,H, Niith thwrganica ChimicaAcn, 269 (1998) 7-12
8
~lm
sb
NI
The results of this analysis are shown in Fig. I and in Table 1. They confirm the expected O-coordination of SbCIs. The amino group (CI, C2, N2, NI) is coplanar with the atoms OI, Sb and CI5. The structure is best represented by formula lb as the NN distance is closer to the length of an N=N double bond ( 120 pro) than of an N-N single bond ( 148 pm) and the NO distance is midway between the length of an N-O single bond ( 145 pro) and an N=O double bond ( 117 pro) [ 24]. A similar but less pronounced trend is found for the binitrosamine cation 2 (Table i). Compared with those in gaseous [ 20,21 ] or solid [ 22] dimethylnitrosamine the NN bond has become shorter, in both 1 and 2, and the NO bond has become longer. In general the difference between NO and NN bond length seems to be a suitable measure for the participation of the polar resonance formula of type b. The difference dNo- dNN (in pm) increases in the order Mc,,NNO (gas) Me,NNO (crystal) (Et2NNO) :Fe (IIl) complex (4) [ (CH,),,NNOICu(II) complex (6) [ (CH2),)NNOI,H" cation (2) (Me,.NNO) SbCIs complex ( I )
-10.9 [211 -6,0 [22] - 2,2 1151 -0,9 see below +0.6[14] +4,8
A structure almost identical to that of I had been found for the dimethyiformamide SbCl~ complex 3 123 ] which differs from 1 only by an isoelectronic N/CH exchange, Judging from its CN and CO distances (Table I ) in comparison with standard bond lengths (C-N, 147 pm; C=N, 122 pm; C=O, 143 pro; C--O, 119 pm [ 241 ) the share of formula b is somewhat smaller for the formamide complex 3 than for the nitrosamine complex 1, The most obvious difference in the structural data is the smaller angle at HI in I compared to that at CH in 3 ( 112.0 versus 120.2°) as is to be expected from valence shell electron pair repulsion (VSEPR). in connection to this the angle at O I is also smaller in I than in 3 (115,7 versus 124.5°). These two differences balance each other and therefore the NN (or CN) bond and the OSb bond are almost parallel in both I and 3. The octahedral Sb coordination in 1 is slightly distorted with two of the angles O-Sb-CI (cis) being (almost) equal to 900 and two being smaller than 90° (average 87 °) and with all of the complementary angles CI5-Sb--CI being larger than 900 (average 93°). The same holds true I b r compound 3 (Table I ). The SbO distance of I falls within the wide range (Table 2) observed for o x o compound SbCI5 complexes [ 25 ], The fact that the bond is considerably longer in I than in 3 is explained by the electronegativity increase connected to the CHIN exchange.
(~~
(P i c~2
Fig. i. M,'lecular structure of I in the crystal (thermal ellipsoids with 25% probability). Table I Bond lengths (pm) and angles (°) of I and of dimethylnitrosamine in the gaseous state (electron diffraction) [ 20,211 and in the solid state (X-ray diffraction) [22] as well as of 2 [ 14] and 3 [23] for comparison
CI-N2 C2-N2 NI-N2 NI-OI OI-Sb Sb-CI I Sb-CI2 Sb-CI3 Sb-CI4 Sb-CI5 CI-N2-C2 CI~N2-NI C2~N2=NI N2=N I ~OI N I ~O I-Sh 01 ~Sb=CI I O1~S~CI2 OI-Sb-CI3 OI-Sb-CI4 OI-Sb-CI5 CI I-Sb-CI2 CII-Sb-CI3 El I -Sb-CI4 CII-Sb--CI5 CI2-Sb...CI3 CI2-Sb--CI4 CI2-Sb-CI5 CI3-Sb-CI4 CI3-Sb-CI5 CI4-Sb.-CI5
Me2NNO (gas)
Me=,NNO (crystal)
1
2
3
146.1(2) 134.4(2) 123.5(2)
146.5(7) 146.1(7) 132.0(6) 126.0(6)
147.0(6) 146,4(6) 126.2(5) 131.0(5) 211.3(3) 234.6( I ) 235.0( I ) 234.5( I ) 236.4( I ) 234,4( I )
145.4(7) 147.5(7) 127,0(6) 127.6(6)
150.4(12) 150.5(14) 128.7(12) a 130.0(10) a 204.8(6) 233.2(3) 233.6(3) 234.2(3) 235.3(3) 233.0(3)
123,2(2) 116.4(3) 120,3f 3) 113,6(2)
120,0(4) 117,4(4) 122.6(4) 114,3(3)
119,3(4) 115,6(4) 125.1(4) 112,0(3) 115.7(2) 84,7( I ) 83.4( I ) 90.0( I ) 89.7( I ) 175.5( I ) 90. I ( I ) 174.5( I ) 89.5( I ) 92.4( I ) 90.8( ! ) 173.2( I ) 93.2( I ) 88.9( I ) 93.0( I ) 93.6( I )
112,7(5) 120.9(5) 126,4(5) 111.4(5)
117.7(9) 120.2(9)" 122,1(8)" 120,2(9)" 124,S(6) " 843(2) 85,2(2) 88.7(2) 89,4(2 ) 177.1(2) 89.7( I ) 173.3( I ) 91.2(I) 93.5( I ) 89.5( I ) 174.4( I ) 92.5( I ) 89.0( I ) 93.2( I ) 92.9( I )
"C in place of N l.
3. N-Nitrosopiperidine CuCIz complex Dimethylnitrosamine and N-nitrosopiperidin¢ and anhydrous copper(ll) chloride form the crystalline reddish brown I:I complexes Me2NNOCuCI2 (5) and (CH2)sNNOCuCIz (6) [ l ] (the corresponding CuBr2 complexes are also known [ 19] ). The structure of $ (Fig. 2) as shown by single crystal X-ray analysis [ 17,18] consists of folded infinite CuCI2
A. Schmidpeter. H. Niith I Inorganica Chimica Acta 269 f 1998) 7-12 Table 2 Average cis-OSbCi bond angles (°) and SbO bend lengths (pm) of oxo compound SbCl~complexes ( Refs. [ 25-27 ] and this paper)
Me3POSbCI~ Me2NCHOSbCI~ (3) Me2NNOSbCIs ( 1 ) Cl2SeOSbCl.~ Me,SO2SbCi~ SsOSbCi~ Ph2SOSbCIs CI3POSbCl~
cis-OSbCI bond angle
SbO bond length
89 87 87 86 86
194 205 21 I 208 212 216 216 217
86 85
Fig. 2, Chain structure of (a) $ and (b) 6 with the 0 atoms (marked) of the nitrosamine molecules at the two sides of the CuCi., chain pointing in the same direction in $ and in opposite directions in 6.
chains made up of almost planar rectangular CuCl4 units sharing their smaller sides. The nitrosamine molecules are fixed to both sides of the chain with their NO groups roughly parallel to the chain axis and all of them pointing in the same direction. The oxygen and the nitrogen atom of a specific nitroso group coordinate to two neighbouring copper atoms. While for most of the other complexes with a L:,CuCI4 coordination two different CuCI bond lengths are observed, the four CuC! bonds of 5 are of equal length and quite short (229 pm, see Table 3). While they are obviously not
9
Table 3 Bond lengths (pro) and angles (°) of the nitrosamine CuCl~ complexes 5 [17,181 and6 6
5
CI-N2 C5-N2 NI-N2 NI-OI OI-Cul CuI-CII Cu I-C12 N l-Cu2 Cu2--CI I Cu2-C12
147.0(4) 148.0(4 ) 128.8(3) 127.9(3) 201.0(2) 264.8( I ) 231A( I ) 260.3(2) 227.3( I ) 232.7( I )
147(3) 146! 3 ) 129(2) 122(2) 229( I ) 228.9(4) 228.9(4) 300( I )
C I-N2-C5 CI-N2-NI C5-N2-N I N2-NI-OI N l--OI-Cu I OI-Cu I-CI I Ol--Cul-Clla OI-CuI-CI2 Ol--Cul-Cl2a CII-Cu I-C12 CI I--Cu I-Cl2a N2-NI-Cu2 OI-N l-Cu2 N I-Cu2-CI I N I-Cu2-CI Ia N I--Cu2-C12 N I--Cu2-CI2a (?Il-Cu2-C12 CI l-Cu2-Cl2a Cu I-CI I-Cu2 Cu I-C12-Cu2
117.0(2) 117.8(2) 125. I (3 ) 114.9(2) 117,2(2) 92,5( I ) 87.5( I ) 91.8( I ) 88.2( I ) 81.93 (2) 98.07 (2 ) 131.9(3) 112.6(3) 84.0( I ) 96.0{ I ) 80.4( I ) 99.6( i ) 90.4 (2) 89.6( 2 ) 82.75 (2 ) 89.43( I )
122.1 ( I ) 118.2( I ) I 19.8( I ) 115.9( I ) 115.52(3) 93.91( I )
86.06( I )
78.34(3)
88.74 ( I )
involved in a Jahn-Teller distortion, an elongation is found of the CuO bond (229pm compared with 196pro in CuCi2(H20)2 [28]) and an even more marked one of the CuN distance (300 pro, compared with 202 pm in CuCI2(pyridine) 2 [ 29] ). The coordination thus approaches a tetragonal pyramid (Fig. 4). The structure of r challenges a comparison with the result of the new X-ray structure analysis of 6 (Fig. 3 and Table 3): the basic structure of 6 is the same as that of[;. It again consists of a slightly folded CuCI2 chain with nitrosamine molecules attached to both sides of the chain and the nitroso group roughly parallel to the chain axis. In contrast to $, the nitroso groups at the two sides of the chain of 6 point in opposite directions (Fig. 2). This seemingly marginal change causes distinct differences in detail. The copper atoms of 6 are no longer equivalent as in 5, but have alternately C!402 and Cl4N2 coordination environments. The two CuO bonds are equal in length and are much shorter (201 pm) than in $. This seems to be compensated by the elongation of two of the CuCI bonds (265 pro, see Fig. 4). The two CuN interactions, although shorter than in 5, are still quite long (260 pro), and as a consequence the CuC! distances in the CuCI4N2 array of 6 are only slightly different (Fig. 4). Both
A. $chmidl~ter, H. NdIh I Im)rganica Chimk'aActa 269 (1998) 7-12
10
uncoordinated and the SbCIs-coordinated nitrosamine of 1 (Table ! ).
4. Determination of the crystal and molecular structures
N2o 01o
Crystals of compounds I and 6 were obtained as described in Ref. [ 1 ]. Warning: Most of the nitrosamines are known as strong carcinogens and their complexes should therefore be handled with due respect for the possible hazards involved [ 32-34]. A Siemens 1)4 X-ray diffractometer equipped with an LT2 low temperature device and a CCD area detector was used for all measurements employing Me Ka radiation and a graphite monochromator. The selected single crystals were covered with a film of perfluoroether oil, mounted on a glass fibre and cooled to 193 K on the goniometer head. The preliminary determination of the dimensions of the unit cell used all data collected on 60 frames recorded in groups of 15 for different ~b and X angles. The final cell dimensions were calculated from 124 reflections for compound I and with all data for compound 6. 1400 frames each were recorded with 10 s exposure time, and the data were then reduced using the program SAINT. Empirical absorption correction was employed using all data with ! > 20(r(l). The structures were solved by the heavy atom method as implemented in the program SHELXTL [35]. Non-hydrogen atoms were refined in an anisotropic description. The positions of the hydrogen atoms were calculated and included in the linal refinement with a riding modal and a fixed isotropic Uadjusted to 1.2U,~qofthe respective carbon atom. Typical data referring to crystallography, data collection and structure solution are collected in Table 4.
CI2
Cul
Cu2 01%N
1
~11o _
CJ2o
Fig. 3. Structure of two formula units of polymeric 6 in the crystal (thermal ellipsoids with 25% probability).
of the two different CuCI4moieties of 6 are planar, each forms a parallelogram that around Cu2 being close to a square. There is one more example known of a I:1 complex of CuCl= with a 1,2-bidentate ligand: the structure of the 1,2,4triazole complex HN(CHN),CuCI~ (7) [30,31 ] also consists of slightly folded CuCl2 chains to both sides of which the triazole molecules are coordinated by bonds from the two adjacent nitrogen atoms to two neighbouring copper atoms. The CuN distances in 7 are significantly shorter ( 198 pm) than in 6 and the elongation of one pair of trans-CuCI bonds therefore is much more pronounced than in the CuCI4N2 moiety of 6, Fig. 4 demonstrates the interdependence of the CuO,N distances and the distortion of the CuCI4 plane in S and '/and in the two different sites of 6, As in $ the nitrosamine skeleton in 6 (CI, C5, N2, HI, OI) forms a plane incorporating the copper atoms. The distinct difference of the Cue bonds in 5 and 6 is reflected in the bond lengths of the coordinated nitrosamine. While the NO bond in $ is as short (Table 3) as in the uncoordinated nitrosamine, that in 6 is longer ranging between those of the 0 12~
0
' cr'-
:~CuO,N)
Additional information on the crystal structure determination are deposited at the Cambridge Crystallographic Data centre and may be requested by quoting the depositing numbers CSD 407828 and 407829, the name of the authors and the journal citation.
N i260
'
~CuCl)
5. Supplementary material
i
N
..........
c,
-cl
o,
.........
2
]300 N
1260 N
0
N
S
6
6
7
529
520
402
396
o
6
34
43
Fig, 4, Jahn-Teller distortion of ~:tal'-..'dralCuCI2(O,N ), units in 5, 6 and 7: Individual distances: sum of Cu-O,N distancesand difference of the two Cu-CI distances (pro),
A. Schmidpeter, It, N6th I h~organica Chimica Acta 269 f 1998; 7-12
Table 4 Crystallographic data of compounds I and 6
Formula Formula weight Crystal size (ram) Crystal system Space group a (~ ) b (~) c (A) /3 (o) Volume (~:~) Z d~al~(Mg m - ~) p, (mm-I) F(000) 20 range (*) Index ranges
Collected reflections mde~,':dent reflections Observed reflections Weighting scheme w - ' Data-to-parameter ratio RI [ F > 4 o ' ( F ) ] wR2 GOF on F" Largest difference peak (e A-+) Largest difference hole (e A " ~) Min,lmax. transmission
Compound I
Compound 6
C.,H~CIsN2OSb 373.09 0.35 x 0.25 x 0.2 colorless needle fragment monoclinic P2t/n (No. 14) 8.860( 2 ) 13.150(3) 9.540(2) 92.58(3) I ! i0.4(4) 4 2.232 3.641
CsHmCI2CuN20 248.59 0.33 x0.25 x 0.2 reddish brown prism monoclinic P21/c (No. 14) 6.5294( 2 ) 16.7236(3) 8.5990(2) ! 12.210( ! ) 869.30(4) 4 2.385 5.453 616 4.88-55.92
704 5.28-57.98 - 10 <_ h _< 10 - 16 4o-(F) ) o-"F,,: + ( 0.0572P ) 2 + 2 2925P P = iF,," + 2Fc')/3 20.2:1 ( 19.2:1 [F> 4o-(F) ] ) 0.037 O.100 I. i 73 1.170 - 2.129
Acknowledgements We thank Dipl.-Chem. JOrg Knizck Ior assistance in the X-ray structure analysis. References [11 A. Schmidpeter, Chem. Ber., 96 (1963) 3275. [21 J. Goubeau, Angew. Chem., 73 ( 1961 ) 305. [31 A. Schmidpeter, Angew. Chem., 75 (1963) I I I I; Angew. Chem., int. Ed. Engl., 3 (1964) 151. t41 W.S. Layne, H.H. Jafft~ and H. Zimmer, J. Am. Chem. Soc., 85 (1963) 435. 151 S.J. Kuhn and J.S. Mclntyre, Can. J. Chem., 55 (1966) 105. 161 L.K. Keefer, L. Ohannesian mtd J.A. Hrabie, J. Org. Chem., 54 (1989) 2432, and Refs. therein. [71 S. Htinig, L. Geldem and E. LOcke, Angew. Chem., 75 (1963) 476; Angew. Chem., int. Ed. Engl., 2 (1963) 327. 18] K. Hafner and K. Wagner, Angew. Chem., 75 (1963) ii04; Angew, Chem., Int. Ed. Engi., 2 (1963) 740. 191 A. Schmidpeter, Tetrahedron Lett., (1963) 142 I. [101 S. Hfinig, G. Btittner, J. Cramer, L. Geldem, H. Hansen and E. LOcke, Chem. Ber., 102 (1969) 2093. [111 G. Btittner and S. Hfinig, Chem. Bet., 104 (1971) 1088. [121 L. Ohannesian and L.K. Keefer, Tetrahedron Lett., 29 (1988) 2903.
- 8 ~; h < 4
- 20 4o-(F) ) o"-F,: + ( 0.03 ! 6P ) -"+ 1.0084P P = (Fo" + 2F:')/3 9.5:1 (8.6:! [F>4O-(F) ] ) 0.029 0.068 !. 154 0.822 - 1.020 0.2648/0.3357
ll3l D. Klamann and W. Koser, Angew. Chem., 75 (1963) 1104; Angew. Chem., Int. Ed. Engl., 2 (1963) 741. i l 4 ] L. Keefer, J.A. Hrabie, L. Ohannesian, J.L. Flippen.Anderson and C. George, J. Am. Chem. So¢., 110 (1988) 3701. 1151 G.-B. Yi, M.A. Khan and G.B. Richter-Addo, J. Am. Chem. So¢., 117 (1995) 7850. [161 R.D. Brown and G.E. Coates, J, Chem. Soc.(1962) 4723. It7] U. Klement and A. Schmidpeter, Angew. Chem., 80 (1968) 444: Angew. Chem., Int. Ed. Engl., 7 (1968,) 470. [t81 U. Klement, Acta Crystallogr., Sect. B, 25 (1969) 2460. ll9] T. Asaji, H. Sakai and D. Nakamum, lnorg. Chem., 22 (1983) 202. 120] P. Rademacher, R. Stolevik and W. Ltittke, Angew. Chem., 80 (1968) 842; Angew. Chem., Int. Ed. Engl., 7 (1968) 806. 121] P. Rademacher and R. Stolevik, Acta Chem. S¢and., 23 (1969) 660. 122l B. Krebs and J. Mandt, Chem. Ber., 108 (1975) 1130. 123] L. Brun and C.-I. Brltnddn, Acta. Crystallogr., 20 (1966) 749. t24] N. Wiberg, Lehrbuch der Anorganischen Chemie, Vol. 101, Walter de Gruyter, Berlin, 1995, p. 1842. 1251 I. Lindqvist, Inorganic Adduct Molecules of Oxo Compounds. Springer, Berlin, 1963, p. 76. [261 Y. Hermodsson, Acta Chem. Scand., 21 (1967) 1313. [271 R. Steudel, T. Sandow mid J. Steidel, J. Chem. See., Chem. Commun., (1980) 181. [28l ,~. Engberg, Acta Chem. Scand., 24 (1970) 3510. [29] J.D. Dunitz, Acta Crystailogr., 10 (1957) 307. [30] J.A.J. Jarvis and A.F. Wells, Acta Crystallogr., 13 (1960) 1027. [311 J.AJ, Jarvis, Acta Crystallogr., 15 (1962) 964.
12
A. ,.¢cbmidpeter, It. N~ith I lnorganica Chimica Acta 269 ¢'1998) 7-12
[32] R. Preussmann and B.W. Stewart, in C,E. Searle (ed,), Chemical Caglnogens, ACS Monograph 182, American Chemical Society, Washing,ton, DC. 1984. p. 643. [331 W. IAjinsky, Chemistry and Biology of N-Nitmso Compounds, Cambridge University Press, Cambridge, 1992.
[ 34] R.N, Loeppky and C.J, Michejda (eds.), Nitmsamines and Related NNitroso Compounds: Chemistry and Biochemisti'y, ACS Symposium Series 553, American Chemical Society, Washington DC, 1994. [35] G.M, Sheldrick, SHELXL-93, program for the refinement of crystal structures, University of GSttingen, Germany, 1993.
Inorganica Chimica Acla 269 (1998) 7-12
Nitrosamine complexes of SbC15 and CuCI: Alfred Schmidpeter *, Heinrich N6th h~stitutfiir Anorganische Chemie, Ludwig-Maxbnilimzs-Universitiit. D-80333 Munich, Germany Received 17 February 1997; revised 8 April 1997; accepted 5 May 1997
Abstract Dialkylnitrosamines form !:1 complexes with SbCls (colourless) and CuCi2 (reddish brown). Me2NNOSbCis (1) crystallizes in the monoclinic space group P2,/n with a = 8.860(2), b = 13.150( 3 ), c = 9.540(2) A,/3 = 92.58 ( 3 )* and Z = 4. The components are joined by a O-Sb bond and the complex is isostructural to that of dimethylformamide Me,NCHOSbCIs. The N-nitrosopiperidine CuCI2 complex (6) crystallizes in the monoclinic space group P2,/c with a = 6.5294(2), b = ! 6.7236( 3 ), c = 8.5990(2) A,/3 = 1 ! 2.2 ! 0( i ) ° and Z = 4. As in the case of the known dimethylnitrosamine CuCI, complex (5) the structure consists of infinite doubly chlorobridged CuCi, chains to both sides of which nitrosamine molecules are coordinated both by the O atom and the N atom of their nitroso group. While the nitroso groups of the dimethylnitrosamine molecules point in the same direction at either side of the chain resulting in a uniform CuCI4ON array in $, the nitrosopiperidine molecules at the two sides of the chain are arranged in opposite directions resulting in alternating CuCI40., and CuCI4N., arrays in 6. In the latter coordination the Jahn-Teiler distortion results in an elongation of the CuN, axis, while in the former an elongation of two of the CuCI bonds is noted. © 1998 Elsevier Science S.A. Keywords: Antiunony complexes; Crystal structures; Nitrosamine complexes; Copper complexes
I. Introduction Like other acid amides and in particular like carbonic acid amides nitrosamines are ambident ligands offering an acceptor the alternative of coordination through the aminogroup nitrogen atom or through the oxygen atom. Nitrosamines have the potential to coordinate via their central nitrogen atom as a third alternative III. While initially a coordination to the aminogroup nitrogen atom had been assumed tbr the dialkylnitrosamine BF3 complexes 121, later on an O-coordination was shown for all the main group acceptors investigated. These interactions include the protonation [3-6], alkylation [ 3,7-111 and silylation [ 121 of nitrosamines as well as the addition of ZnBr2, BF3, AICI.a, PCI.~, SbCI.~, and SO~ [ 1,131 to nitrosamines. An X-ray structure analysis so far seems available only of the binitrosamine cation in 2114 i. This paper now reports the structure of the complex Me2NNOSbCI.~ (1). Also with transition metal centres, a sole O-coordination has been found for the bis(diethylnitrosamine) complex 4 of tetraphenylporphyrinatoiron (III) by X-ray structure analysis 115] and has been suggesteu Ibr bis(nitrosamine) PdCI2 complexes [161. However, O-coor* Corresponding author: Tel.: + 49 89 5902 249; fax: + 49 89 5902 578. n Dedicated to Professor Wolfgang Beck on the occasion of his 65th birthday. 0020-1693/98 / $19.00 © 1998 Elsevier Science S.A. All rights reserved Pll S 0 0 2 0 - i 693 ( 97 ) 0 5 7 6 8 - X
dination seems not to be the only interaction in nitrosamine complexes of transition metal chlorides [ I ]. This is shown in particular by an X-ray structure analysis of the dimethylnitrosamine CuCl,, complex ($) [ 17,18], which in the present paper will be compared with the somewhat deviating structure of the CuCI2 complex 6 of N-nitrosopiperidine (the corresponding CuBr2 complexes are also known [ 19] ).
2. Dimethylnitrosamine SbCI~ complex Dimethylnitrosamine forms a stable i:I complex 1 with antimony pentachloride [ 1 ]. Recrystallization fromdichloromethane yields colourless crystals suitable for X-ray structure analysis.
.,e
.,% N--N
H3C'
~
N--N
*d-s-bc,
'o-s-bc,
la
~
1b
~=N
N--N
PF~"
O--H"-C)~kN__N~ 2
A. Sehmidpeter,H, Niith thwrganica ChimicaAcn, 269 (1998) 7-12
8
~lm
sb
NI
The results of this analysis are shown in Fig. I and in Table 1. They confirm the expected O-coordination of SbCIs. The amino group (CI, C2, N2, NI) is coplanar with the atoms OI, Sb and CI5. The structure is best represented by formula lb as the NN distance is closer to the length of an N=N double bond ( 120 pro) than of an N-N single bond ( 148 pm) and the NO distance is midway between the length of an N-O single bond ( 145 pro) and an N=O double bond ( 117 pro) [ 24]. A similar but less pronounced trend is found for the binitrosamine cation 2 (Table i). Compared with those in gaseous [ 20,21 ] or solid [ 22] dimethylnitrosamine the NN bond has become shorter, in both 1 and 2, and the NO bond has become longer. In general the difference between NO and NN bond length seems to be a suitable measure for the participation of the polar resonance formula of type b. The difference dNo- dNN (in pm) increases in the order Mc,,NNO (gas) Me,NNO (crystal) (Et2NNO) :Fe (IIl) complex (4) [ (CH,),,NNOICu(II) complex (6) [ (CH2),)NNOI,H" cation (2) (Me,.NNO) SbCIs complex ( I )
-10.9 [211 -6,0 [22] - 2,2 1151 -0,9 see below +0.6[14] +4,8
A structure almost identical to that of I had been found for the dimethyiformamide SbCl~ complex 3 123 ] which differs from 1 only by an isoelectronic N/CH exchange, Judging from its CN and CO distances (Table I ) in comparison with standard bond lengths (C-N, 147 pm; C=N, 122 pm; C=O, 143 pro; C--O, 119 pm [ 241 ) the share of formula b is somewhat smaller for the formamide complex 3 than for the nitrosamine complex 1, The most obvious difference in the structural data is the smaller angle at HI in I compared to that at CH in 3 ( 112.0 versus 120.2°) as is to be expected from valence shell electron pair repulsion (VSEPR). in connection to this the angle at O I is also smaller in I than in 3 (115,7 versus 124.5°). These two differences balance each other and therefore the NN (or CN) bond and the OSb bond are almost parallel in both I and 3. The octahedral Sb coordination in 1 is slightly distorted with two of the angles O-Sb-CI (cis) being (almost) equal to 900 and two being smaller than 90° (average 87 °) and with all of the complementary angles CI5-Sb--CI being larger than 900 (average 93°). The same holds true I b r compound 3 (Table I ). The SbO distance of I falls within the wide range (Table 2) observed for o x o compound SbCI5 complexes [ 25 ], The fact that the bond is considerably longer in I than in 3 is explained by the electronegativity increase connected to the CHIN exchange.
(~~
(P i c~2
Fig. i. M,'lecular structure of I in the crystal (thermal ellipsoids with 25% probability). Table I Bond lengths (pm) and angles (°) of I and of dimethylnitrosamine in the gaseous state (electron diffraction) [ 20,211 and in the solid state (X-ray diffraction) [22] as well as of 2 [ 14] and 3 [23] for comparison
CI-N2 C2-N2 NI-N2 NI-OI OI-Sb Sb-CI I Sb-CI2 Sb-CI3 Sb-CI4 Sb-CI5 CI-N2-C2 CI~N2-NI C2~N2=NI N2=N I ~OI N I ~O I-Sh 01 ~Sb=CI I O1~S~CI2 OI-Sb-CI3 OI-Sb-CI4 OI-Sb-CI5 CI I-Sb-CI2 CII-Sb-CI3 El I -Sb-CI4 CII-Sb--CI5 CI2-Sb...CI3 CI2-Sb--CI4 CI2-Sb-CI5 CI3-Sb-CI4 CI3-Sb-CI5 CI4-Sb.-CI5
Me2NNO (gas)
Me=,NNO (crystal)
1
2
3
146.1(2) 134.4(2) 123.5(2)
146.5(7) 146.1(7) 132.0(6) 126.0(6)
147.0(6) 146,4(6) 126.2(5) 131.0(5) 211.3(3) 234.6( I ) 235.0( I ) 234.5( I ) 236.4( I ) 234,4( I )
145.4(7) 147.5(7) 127,0(6) 127.6(6)
150.4(12) 150.5(14) 128.7(12) a 130.0(10) a 204.8(6) 233.2(3) 233.6(3) 234.2(3) 235.3(3) 233.0(3)
123,2(2) 116.4(3) 120,3f 3) 113,6(2)
120,0(4) 117,4(4) 122.6(4) 114,3(3)
119,3(4) 115,6(4) 125.1(4) 112,0(3) 115.7(2) 84,7( I ) 83.4( I ) 90.0( I ) 89.7( I ) 175.5( I ) 90. I ( I ) 174.5( I ) 89.5( I ) 92.4( I ) 90.8( ! ) 173.2( I ) 93.2( I ) 88.9( I ) 93.0( I ) 93.6( I )
112,7(5) 120.9(5) 126,4(5) 111.4(5)
117.7(9) 120.2(9)" 122,1(8)" 120,2(9)" 124,S(6) " 843(2) 85,2(2) 88.7(2) 89,4(2 ) 177.1(2) 89.7( I ) 173.3( I ) 91.2(I) 93.5( I ) 89.5( I ) 174.4( I ) 92.5( I ) 89.0( I ) 93.2( I ) 92.9( I )
"C in place of N l.
3. N-Nitrosopiperidine CuCIz complex Dimethylnitrosamine and N-nitrosopiperidin¢ and anhydrous copper(ll) chloride form the crystalline reddish brown I:I complexes Me2NNOCuCI2 (5) and (CH2)sNNOCuCIz (6) [ l ] (the corresponding CuBr2 complexes are also known [ 19] ). The structure of $ (Fig. 2) as shown by single crystal X-ray analysis [ 17,18] consists of folded infinite CuCI2
A. Schmidpeter. H. Niith I Inorganica Chimica Acta 269 f 1998) 7-12 Table 2 Average cis-OSbCi bond angles (°) and SbO bend lengths (pm) of oxo compound SbCl~complexes ( Refs. [ 25-27 ] and this paper)
Me3POSbCI~ Me2NCHOSbCI~ (3) Me2NNOSbCIs ( 1 ) Cl2SeOSbCl.~ Me,SO2SbCi~ SsOSbCi~ Ph2SOSbCIs CI3POSbCl~
cis-OSbCI bond angle
SbO bond length
89 87 87 86 86
194 205 21 I 208 212 216 216 217
86 85
Fig. 2, Chain structure of (a) $ and (b) 6 with the 0 atoms (marked) of the nitrosamine molecules at the two sides of the CuCi., chain pointing in the same direction in $ and in opposite directions in 6.
chains made up of almost planar rectangular CuCl4 units sharing their smaller sides. The nitrosamine molecules are fixed to both sides of the chain with their NO groups roughly parallel to the chain axis and all of them pointing in the same direction. The oxygen and the nitrogen atom of a specific nitroso group coordinate to two neighbouring copper atoms. While for most of the other complexes with a L:,CuCI4 coordination two different CuCI bond lengths are observed, the four CuC! bonds of 5 are of equal length and quite short (229 pm, see Table 3). While they are obviously not
9
Table 3 Bond lengths (pro) and angles (°) of the nitrosamine CuCl~ complexes 5 [17,181 and6 6
5
CI-N2 C5-N2 NI-N2 NI-OI OI-Cul CuI-CII Cu I-C12 N l-Cu2 Cu2--CI I Cu2-C12
147.0(4) 148.0(4 ) 128.8(3) 127.9(3) 201.0(2) 264.8( I ) 231A( I ) 260.3(2) 227.3( I ) 232.7( I )
147(3) 146! 3 ) 129(2) 122(2) 229( I ) 228.9(4) 228.9(4) 300( I )
C I-N2-C5 CI-N2-NI C5-N2-N I N2-NI-OI N l--OI-Cu I OI-Cu I-CI I Ol--Cul-Clla OI-CuI-CI2 Ol--Cul-Cl2a CII-Cu I-C12 CI I--Cu I-Cl2a N2-NI-Cu2 OI-N l-Cu2 N I-Cu2-CI I N I-Cu2-CI Ia N I--Cu2-C12 N I--Cu2-CI2a (?Il-Cu2-C12 CI l-Cu2-Cl2a Cu I-CI I-Cu2 Cu I-C12-Cu2
117.0(2) 117.8(2) 125. I (3 ) 114.9(2) 117,2(2) 92,5( I ) 87.5( I ) 91.8( I ) 88.2( I ) 81.93 (2) 98.07 (2 ) 131.9(3) 112.6(3) 84.0( I ) 96.0{ I ) 80.4( I ) 99.6( i ) 90.4 (2) 89.6( 2 ) 82.75 (2 ) 89.43( I )
122.1 ( I ) 118.2( I ) I 19.8( I ) 115.9( I ) 115.52(3) 93.91( I )
86.06( I )
78.34(3)
88.74 ( I )
involved in a Jahn-Teller distortion, an elongation is found of the CuO bond (229pm compared with 196pro in CuCi2(H20)2 [28]) and an even more marked one of the CuN distance (300 pro, compared with 202 pm in CuCI2(pyridine) 2 [ 29] ). The coordination thus approaches a tetragonal pyramid (Fig. 4). The structure of r challenges a comparison with the result of the new X-ray structure analysis of 6 (Fig. 3 and Table 3): the basic structure of 6 is the same as that of[;. It again consists of a slightly folded CuCI2 chain with nitrosamine molecules attached to both sides of the chain and the nitroso group roughly parallel to the chain axis. In contrast to $, the nitroso groups at the two sides of the chain of 6 point in opposite directions (Fig. 2). This seemingly marginal change causes distinct differences in detail. The copper atoms of 6 are no longer equivalent as in 5, but have alternately C!402 and Cl4N2 coordination environments. The two CuO bonds are equal in length and are much shorter (201 pm) than in $. This seems to be compensated by the elongation of two of the CuCI bonds (265 pro, see Fig. 4). The two CuN interactions, although shorter than in 5, are still quite long (260 pro), and as a consequence the CuC! distances in the CuCI4N2 array of 6 are only slightly different (Fig. 4). Both
A. $chmidl~ter, H. NdIh I Im)rganica Chimk'aActa 269 (1998) 7-12
10
uncoordinated and the SbCIs-coordinated nitrosamine of 1 (Table ! ).
4. Determination of the crystal and molecular structures
N2o 01o
Crystals of compounds I and 6 were obtained as described in Ref. [ 1 ]. Warning: Most of the nitrosamines are known as strong carcinogens and their complexes should therefore be handled with due respect for the possible hazards involved [ 32-34]. A Siemens 1)4 X-ray diffractometer equipped with an LT2 low temperature device and a CCD area detector was used for all measurements employing Me Ka radiation and a graphite monochromator. The selected single crystals were covered with a film of perfluoroether oil, mounted on a glass fibre and cooled to 193 K on the goniometer head. The preliminary determination of the dimensions of the unit cell used all data collected on 60 frames recorded in groups of 15 for different ~b and X angles. The final cell dimensions were calculated from 124 reflections for compound I and with all data for compound 6. 1400 frames each were recorded with 10 s exposure time, and the data were then reduced using the program SAINT. Empirical absorption correction was employed using all data with ! > 20(r(l). The structures were solved by the heavy atom method as implemented in the program SHELXTL [35]. Non-hydrogen atoms were refined in an anisotropic description. The positions of the hydrogen atoms were calculated and included in the linal refinement with a riding modal and a fixed isotropic Uadjusted to 1.2U,~qofthe respective carbon atom. Typical data referring to crystallography, data collection and structure solution are collected in Table 4.
CI2
Cul
Cu2 01%N
1
~11o _
CJ2o
Fig. 3. Structure of two formula units of polymeric 6 in the crystal (thermal ellipsoids with 25% probability).
of the two different CuCI4moieties of 6 are planar, each forms a parallelogram that around Cu2 being close to a square. There is one more example known of a I:1 complex of CuCl= with a 1,2-bidentate ligand: the structure of the 1,2,4triazole complex HN(CHN),CuCI~ (7) [30,31 ] also consists of slightly folded CuCl2 chains to both sides of which the triazole molecules are coordinated by bonds from the two adjacent nitrogen atoms to two neighbouring copper atoms. The CuN distances in 7 are significantly shorter ( 198 pm) than in 6 and the elongation of one pair of trans-CuCI bonds therefore is much more pronounced than in the CuCI4N2 moiety of 6, Fig. 4 demonstrates the interdependence of the CuO,N distances and the distortion of the CuCI4 plane in S and '/and in the two different sites of 6, As in $ the nitrosamine skeleton in 6 (CI, C5, N2, HI, OI) forms a plane incorporating the copper atoms. The distinct difference of the Cue bonds in 5 and 6 is reflected in the bond lengths of the coordinated nitrosamine. While the NO bond in $ is as short (Table 3) as in the uncoordinated nitrosamine, that in 6 is longer ranging between those of the 0 12~
0
' cr'-
:~CuO,N)
Additional information on the crystal structure determination are deposited at the Cambridge Crystallographic Data centre and may be requested by quoting the depositing numbers CSD 407828 and 407829, the name of the authors and the journal citation.
N i260
'
~CuCl)
5. Supplementary material
i
N
..........
c,
-cl
o,
.........
2
]300 N
1260 N
0
N
S
6
6
7
529
520
402
396
o
6
34
43
Fig, 4, Jahn-Teller distortion of ~:tal'-..'dralCuCI2(O,N ), units in 5, 6 and 7: Individual distances: sum of Cu-O,N distancesand difference of the two Cu-CI distances (pro),
A. Schmidpeter, It, N6th I h~organica Chimica Acta 269 f 1998; 7-12
Table 4 Crystallographic data of compounds I and 6
Formula Formula weight Crystal size (ram) Crystal system Space group a (~ ) b (~) c (A) /3 (o) Volume (~:~) Z d~al~(Mg m - ~) p, (mm-I) F(000) 20 range (*) Index ranges
Collected reflections mde~,':dent reflections Observed reflections Weighting scheme w - ' Data-to-parameter ratio RI [ F > 4 o ' ( F ) ] wR2 GOF on F" Largest difference peak (e A-+) Largest difference hole (e A " ~) Min,lmax. transmission
Compound I
Compound 6
C.,H~CIsN2OSb 373.09 0.35 x 0.25 x 0.2 colorless needle fragment monoclinic P2t/n (No. 14) 8.860( 2 ) 13.150(3) 9.540(2) 92.58(3) I ! i0.4(4) 4 2.232 3.641
CsHmCI2CuN20 248.59 0.33 x0.25 x 0.2 reddish brown prism monoclinic P21/c (No. 14) 6.5294( 2 ) 16.7236(3) 8.5990(2) ! 12.210( ! ) 869.30(4) 4 2.385 5.453 616 4.88-55.92
704 5.28-57.98 - 10 <_ h _< 10 - 16
Acknowledgements We thank Dipl.-Chem. JOrg Knizck Ior assistance in the X-ray structure analysis. References [11 A. Schmidpeter, Chem. Ber., 96 (1963) 3275. [21 J. Goubeau, Angew. Chem., 73 ( 1961 ) 305. [31 A. Schmidpeter, Angew. Chem., 75 (1963) I I I I; Angew. Chem., int. Ed. Engl., 3 (1964) 151. t41 W.S. Layne, H.H. Jafft~ and H. Zimmer, J. Am. Chem. Soc., 85 (1963) 435. 151 S.J. Kuhn and J.S. Mclntyre, Can. J. Chem., 55 (1966) 105. 161 L.K. Keefer, L. Ohannesian mtd J.A. Hrabie, J. Org. Chem., 54 (1989) 2432, and Refs. therein. [71 S. Htinig, L. Geldem and E. LOcke, Angew. Chem., 75 (1963) 476; Angew. Chem., int. Ed. Engl., 2 (1963) 327. 18] K. Hafner and K. Wagner, Angew. Chem., 75 (1963) ii04; Angew, Chem., Int. Ed. Engi., 2 (1963) 740. 191 A. Schmidpeter, Tetrahedron Lett., (1963) 142 I. [101 S. Hfinig, G. Btittner, J. Cramer, L. Geldem, H. Hansen and E. LOcke, Chem. Ber., 102 (1969) 2093. [111 G. Btittner and S. Hfinig, Chem. Bet., 104 (1971) 1088. [121 L. Ohannesian and L.K. Keefer, Tetrahedron Lett., 29 (1988) 2903.
- 8 ~; h < 4
- 20
ll3l D. Klamann and W. Koser, Angew. Chem., 75 (1963) 1104; Angew. Chem., Int. Ed. Engl., 2 (1963) 741. i l 4 ] L. Keefer, J.A. Hrabie, L. Ohannesian, J.L. Flippen.Anderson and C. George, J. Am. Chem. So¢., 110 (1988) 3701. 1151 G.-B. Yi, M.A. Khan and G.B. Richter-Addo, J. Am. Chem. So¢., 117 (1995) 7850. [161 R.D. Brown and G.E. Coates, J, Chem. Soc.(1962) 4723. It7] U. Klement and A. Schmidpeter, Angew. Chem., 80 (1968) 444: Angew. Chem., Int. Ed. Engl., 7 (1968,) 470. [t81 U. Klement, Acta Crystallogr., Sect. B, 25 (1969) 2460. ll9] T. Asaji, H. Sakai and D. Nakamum, lnorg. Chem., 22 (1983) 202. 120] P. Rademacher, R. Stolevik and W. Ltittke, Angew. Chem., 80 (1968) 842; Angew. Chem., Int. Ed. Engl., 7 (1968) 806. 121] P. Rademacher and R. Stolevik, Acta Chem. S¢and., 23 (1969) 660. 122l B. Krebs and J. Mandt, Chem. Ber., 108 (1975) 1130. 123] L. Brun and C.-I. Brltnddn, Acta. Crystallogr., 20 (1966) 749. t24] N. Wiberg, Lehrbuch der Anorganischen Chemie, Vol. 101, Walter de Gruyter, Berlin, 1995, p. 1842. 1251 I. Lindqvist, Inorganic Adduct Molecules of Oxo Compounds. Springer, Berlin, 1963, p. 76. [261 Y. Hermodsson, Acta Chem. Scand., 21 (1967) 1313. [271 R. Steudel, T. Sandow mid J. Steidel, J. Chem. See., Chem. Commun., (1980) 181. [28l ,~. Engberg, Acta Chem. Scand., 24 (1970) 3510. [29] J.D. Dunitz, Acta Crystailogr., 10 (1957) 307. [30] J.A.J. Jarvis and A.F. Wells, Acta Crystallogr., 13 (1960) 1027. [311 J.AJ, Jarvis, Acta Crystallogr., 15 (1962) 964.
12
A. ,.¢cbmidpeter, It. N~ith I lnorganica Chimica Acta 269 ¢'1998) 7-12
[32] R. Preussmann and B.W. Stewart, in C,E. Searle (ed,), Chemical Caglnogens, ACS Monograph 182, American Chemical Society, Washing,ton, DC. 1984. p. 643. [331 W. IAjinsky, Chemistry and Biology of N-Nitmso Compounds, Cambridge University Press, Cambridge, 1992.
[ 34] R.N, Loeppky and C.J, Michejda (eds.), Nitmsamines and Related NNitroso Compounds: Chemistry and Biochemisti'y, ACS Symposium Series 553, American Chemical Society, Washington DC, 1994. [35] G.M, Sheldrick, SHELXL-93, program for the refinement of crystal structures, University of GSttingen, Germany, 1993.