2754
Inorganic Chemistry, Vol. 9, No. 12, 1970
G. R. CLARKAND Gus J. PALENIK
radii, l7 it is possibly significantly shorter than the values fact that some Se-C multiple-bond character may exist of 2.01 (3) and 1.98 (3) A observed in the saturated in the present structure must not be interpreted to mean that,any significant T bonding between the Ni and heterocycles S ( C Z H ~ ) Z S ~and B~Z O(C2H4)2SeIC120 ~~ in which no T bonding exists. I n addition, the 1.905 (10) Se atoms occurs in this complex. Further structural k value is not significantly longer than the average studies seem necessary before definite conclusions conSe-C distance of 1.87 (1) A in the Ni(SezCN(C~H6)2)~cerning the bonding in selenium donor chelates can be unequivocally established. complex1* or the corresponding value of 1.86 (1) A found in the trigonal prismatic diselenolene complex Acknowledgments -We wish to thank the National Mo(SezC~.(CF3)2)3~~ in which some T delocalization over Science Foundation (Grant GP-8079) and the Advanced the chelate ring is presumed to exist. However, the Research Projects Agency for support of this research. (19) L. Battelle, C. Knobler, and J. D. McCullough, Inovg. Chem., 6, 958 We also express our appreciation t o Professor Devon (1967). (20) C. Knobler and J. D. McCullough, i b i d . , 7, 365 (1968). Meek for the sample of the complex and for his helpful (21) C. G. Pierpont and R. Eisenberg, submitted for publication in J . comments. Chem. SOC.A .
CONTRIBUTION FROX THE DEPARTMENT O F CHEMISTRY, UNIVERSITY OF WATERLOO, WATERLOO, ONTARIO, CANADA
The Crystal and Molecular Structure of Isothiocyanatothiocyanato(1 diphenylphosphino 3-dimethy1aminopropane)palladium(I I)
-
-
BY G. R. CLARK
AND
GUS J. PALENIK*
Received February 25, 1970 The orange compound P d [(CF,H~)ZPCHZCHZCHZN(CH~)Z] (SCN)(NCS) is monoclinic, with cell parameters a = 11.684 =k 0.003, b = 12.961 3~ 0.004, c = 14.641 A 0.003 b, and p = 110.04 rt 0.01'. The space group is P2i/c with four molecules per unit cell, d, = 1.578 A 0.002 g/cm3 and dm = 1.567 A 0.005 g/cm3. Diffractometer data were collected for Cu K a radiation and the structure has been refined by least-squares methods with anisotropic thermal parameters to a final R of 0.041 for 2716 observed reflections. The palladium atom is four-coordinated in a square-planar arrangement. The donor atoms are the phosphorus and nitrogen atoms of the organic ligand and one nitrogen and one sulfur atom from each thiocyanate group. They are arranged with the isothiocyanate linkage trans to the phosphorus atom and the thiocyanate linkage trans to the amine nitrogen atom. Bond distances about the palladium atom show a shortening (Pd-P = 2.243 & 0.002 b; Pd-S = 2.295 f 0.002 b ) and a lengthening (Pd-N(1igand) = 2.147 I-t 0.006 A; Pd-N(NCS) = 2.063 i 0.007 b)consistent with a trans effect.
Introduction The subtle factors influencing the formation of inorganic linkage isomers and particularly those involving the thiocyanate group' are of recent interest. A few compounds have been prepared which are reported t o contain both metal-NCS and metal-SCN bonds (nonbridging) in the same m o l e c ~ l e . ~ -The ~ evidence for these linkage isomers has been based entirely on physical measurements in solution. However, the interpretation of the spectral data has not been conclusive since the C-N or C-S stretching frequencies may be masked by broad bands from other ligands3 or they may coincide with intense overtones from the N-C-S deformation mode.6 Only three X-ray structural studies have been re-
* T o whom correspondence should be addressed. (1) For reviews of the properties of these compounds see J. L. Burmeister, Coord. Chem. Rev., 1, 205 (1966); 3, 225 (1968). (2) I. Bertini and A. Sabatini, Inovg. Chem., 5, 1025 (1966). (3) P.Nicpon and D. W.Meek, ibid., 6, 145 (1967). (4) G. C. Kulasingam and W.R . McWhinnie, Chem. I n d . (London), 2200 (1966). (5) A.J. Carty and A. Efraty, Can. J . Chem., 47,2573 (1969). (6) L. H.Jones, J . Chem. Phys., 18, 1234 (1958).
ported on compounds postulated t o have S- and Nbonded thiocyanate groups. The compound Pd(4,7diphenylphen) (SCN)2 was amorphous. One ionic and one nitrogen-bonded thiocyanate group was found in [Cu(N(CHzCHzNHJ3)(NCS) ](NCS)'r8 and bridging -N-C-S- groups were found in bis(ethy1enethiourea)cadmium thiocyanate. The compound P ~ [ ( C ~ H & P C H Z C H ~ C H ~ N ( C H ~ ) ~ ] (SCN)(NCS) was also believed to exhibit mixed bonding in the solid statelo and we undertook an X-ray examination of this compound to provide structural evidence for this hypothesis. A preliminary report of our results has appeared recently.Il Experimental Section Orange, polyhedral crystals of the complex were kindly supplied by Professor D. W.Meek. Preliminary Weissenberg and precession photographs indicated that the crystals were mono(7) K. N.Raymond and F. Basolo, Inovg. Chem., 5, 1632 (1966). (8) P.C. Jain and E. C. Lingafelter, J . Amer. Chem. Soc., 89,724 (1967). (9) L. Cavalca, M. Nardelli, and G. Fava, Acta Crystallogv., 13, 125 (1960). (10) D.W. Meek, P. E. Nicpon, and V. I. Meek, unpublished results. (11) G. R. Clark, G. J. Palenik, and D. W. Meek, J . Amev. Chem. Soc., 91, 1077 (1970).
Inorganic Chemistry, VoZ. 9, No. 12, 1970 2755
AN ISOTHIOCYANATOTHIOCYANATOPALLADIUM(~~)COMPLEX
+
clinic. The systematic absences of hO1 for I = 2% 1 and OkO for k = 2n 1indicated the space group to be P 2 d c ( Czh6). A crystal was cleaved to give a fragment 0.074 X 0.079 X 0.084 mm which was mounted on a glass fiber. The crystal was aligned on a General Electric single-crystal orienter with the reciprocal lattice vector 503 parallel to the axis of the orienter. Unit cell dimensions were obtained by a least-squares fit of 19 20 values measured for the Cu KO (A 1.39217 b)peak with a takeoff angle of l o . The final lattice constants are a = 11.684 z!= 0.003 A, b = 12.961 i 0.004 b, c = 14.641 f 0.003 A, a n d @= 110.04 0.01’. The density calculated for four molecules per unit cell is 1.578 f 0.002 g/cma; the density determined by flotation in a carbon tetrachloride-cyclohexane solution is 1.567 rt 0.005 g/cm*. Intensity data were measured with a General Electric XRD-6 diffractometer using Cu KCY(X 1.54051 A) radiation with a takeoff angle of 4’. A 0.35-mil Ni foil was placed in front of the counter window. A 20-sec count was taken using the stationarycrystal, stationary-counter technique. Four standard reflections were measured after every 100 reflections to check crystal and instrument stability. A decrease of less than 5y0 was noted and six scale factors were introduced to compensate for the loss of intensity in the standard reflections. Initially a unique set of reflections was measured and then the entire hemisphere was remeasured giving up to three estimations of each unique reflection. A background curve as a function of 20 was obtained by measuring the background a t various points in the hemisphere and averaging the counts obtained a t a given 20 value. A reflection was considered t o be observed if the total counts exceeded the sum of the background plus 3 times the square root of the background. After equivalent reflections were averaged, the 12,523 measurements were reduced t o 2716 observed and 1043 unobserved reflections. The unobserved reflections were entered as half the minimum observable counts and were identified by a negative value for the intensity. An empirical correction (based 1 ora splitting on scanned data from previous crystals) for the ( ~ was made and then these data were reduced t o a set of observed amplitudes on an arbitrary scale by application of Lorentzpolarization corrections. The linear absorption coefficient ( p ) for the crystal with Cu Kor radiation is 99.4 cm-l, with the value of P I varying from 0.37 to 0.68. This variation could produce a 30y0 error in the intensity in the extreme case; however, the variation of intensity as a function of qi (at x = 90’) suggests that the average error was much less.
+
+
+
Solution and Refinement of the Structure The positions of the palladium atom and the coordinated phosphorus and sulfur atoms were located in a three-dimensional sharpened Patterson function. The second sulfur atom was located in a minimum function based on the palladium--palladium vector. The light atoms were located in a Fourier synthesis based on phases calculated from the palladium, phosphorus, and two sulfur atoms. Two full-matrix least-squares cycles using isotropic thermal parameters reduced R, the usual residual, to 0.089. The weighting scheme used was
l / w = Fo/F(low) if Fo < F(1ow) & = 1 if F(1ow) S F, 5 F(high) F, > F(high) where F(1ow) was 20.0 and F(high) was 120.0 (approximately 2.5Fo(minimum) and 15Fo(minimum), respectively). The value of F(1ow) was raised to 25.0 since some of the weaker reflections appeared unreliable. Eight least-squares cycles using a 3 X 3 block for positional parameters and a 6 X 6 block for individual anisotropic thermal parameters reduced R to 4.1%. The = F(high)/F, if
TABLE I THEFINAL POSITIONAL PARAMETERS AND THEIR ESTIMATED STANDARD DEVIATIONS Atom
Pd
%/a
0 14931 (4) 0.32272 (17) -0.10154 (20) 0.27068 (15) -0,0088(5) 0.0403 (5) 0.2718(8) 0.2853 (7) -0.0180 (6) -0.0540 (8) -0.1070 (7) 0.0106 (9) 0.0622 (10) 0.1942 (7) 0.3087 (6) 0.2960 (7) 0.3297 (7) 0.3774 (7) 0.3903 (7) 0.3550 (7) 0.4173 (6) 0.5236 (7) 0.6364 (8): 0.6382 (8) 0.5330 (9) 0.4202 (8) I
s1 s2 P1 N1 N2 N3
c1 c2
c3 c4 c5 C6 c7 C8 c9 c10
c11 c12 C13 C14 C15 C16 C17 C18 c19
0.18570 (4) 0.09676 (18) -0.04728 (18) 0.28884 (13) 0.2773 (5) 0.0877 (5) -0.0470 (7) 0.0133 (6) 0.0309 (5) 0.3159 (9) 0.2105(7) 0.3717(7) 0.3537 (10) 0.3201 (7) 0.4103 (5) 0.4197 (6) 0.5113 (6) 0.5920 (6) 0.5819 (6) 0.4915(6) 0.2364 (5) 0.2683 (6) 0.2240 (7) 0.1485 (7) 0.1183 (8) 0.1612 (6)
0.06147 (4) 0.14727 (17) 0.16607 (18) 0.01188 (13) -0.0116(5) 0.1068 (5) 0.2708 (6) 0.2181 (6) 0.1307 (5) 0.0680 (7) -0.0786 (7) -0.0636(8) -0.1433 (7) -0.1166 (5) 0.0773 (5) 0.1687 (5) 0.2199 (6) 0.1828 (6) 0.0914 (6) 0.0390 (5) 0.0183 (6) 0.0919 (6) 0.0982 (7) 0.0301 (7) -0.0452 (9) -0.0491 (8)
TABLE I1 FINAL THERMAL PARAMETERS ( x lo4)WITH THEIR ESTIMATED STANDARD DEVIATIONS IN PARENTHESES~ Atom
82%
(311
43 (0) 56 (2) s2 95 (2) P1 54 (1) N1 49 (5) N2 69 (6) N3 144 (10) C1 89 (8) C2 65 (6) C3 92 (8) C4 65 (7) C5 116(10) C6 151 (12) C7 119 (8) C8 57 (6) C9 87 (7) C10 101 (8) C11 68(7) C12 88(7) C13 85 (7) C14 73 (7) C15 71 (7) C16 94 (8) C17 97 (8) C18 lOS(10) C l 9 114(9) Pd S1
13331’
35 (0) 71 (2) 68 (2) 33 (1) 48 (4) 59 (5) 100 (7) 57 (5) 41 (4) 113 (9) 83 (7) 77 (7) 189 (14) 76 (6) 42 (4) 65 (6) 68 (6) 57 (5) 53 (5) 44 (6) 42 (4) 69 (6) 86 (7) 68 (6) 79 (8) 58 (6)
@la
(388
44 (0) 74 (1) 81 (2) 40 (1) 65 (4) 64 (4) 81 (6) 54 (5) 48 (4) 91 (7) 81 (6) 118 (9) 67 (7) 32 (4) 45 (4) 46 (4) 50 (5) 58 (5) 62 (5) 55 (5) 68 (5) 61 (5) 77 (6) 120 (8) 148 (10) 122 (8)
018
-
The temperature factor is of the form exp[ - (@I# Pi& Pi3hZ 82akl).
+
+
+
P28
8 (1) 4 (1) 31 (0) 65 (3) 45 (3) 44 (3) -64 (3) -1 (3) 89 (3) 4 (2) 42 (2) -4 (2) 14 (7) 37 (7) 16 (7) -17 (8) 21 (7) 56 (8) 77 (11) 47 (14) 63 (12) 45 (11) 26 (10) 20 (9) -7 (7) - 5 (8) 29 (8) 58 (12) -61 (14) 87 (15) -19 (11) -37 (11) 18 (11) 96 (13) 72 (15) 89 (14) 128 (16) 83 (15) 153 (22) 10 (13) 12 (9) 31 (9) -5 (7) 9 (8) 38 (8) 12 (10) 56 (9) -5 (8) -12 (11) 60 (11) -13 (9) -19 (9) 13 (9) 5 (10) 49 (10) - 17 (10) - 5 (9) 54 (10) 16 (9) 3 (8) 83 (10) 6 (8) -6 (9) 15 (10) 50 (10) 39 (9) 53 (11) 47 (12) 83 (12) 54 (11) 137 (15) 35 (12) -56 (14) 1 ~ 4 ) 155 (7) 22 (12) 143 (15) -57 (11)
+ P2zk2 +
largest shift of any parameter in the last cycle was less than one-eighth of a standard deviation ; therefore the refinement was considered completed. Atomic scattering factors for Pd, S, and N were taken from ref 12 and for P and C from hfs wave functions.13 Because of the variation in reported values for the Af’ correction for Pd for Cu Ka radiation,12-14 no disper(12) “Internati nal Tables fur X-Ray Crystallography,” Vol. 111, Kynoch Press, BirminghaA England, 1962, p 201. (13) H. P. Hadson, F. Herman, J. D. Lea, and S. Skillman, Acta Crystallogr., 17, 1040 (1964). (14) D. T. Crumer, A. C. Larson, and J. T. Waber, i b i d . , 17, 1044 (1964).
2756 Inorganic Chemistry, Vol. 9,No. 12, 1970
G. R. CLARKAND Gus J. PALENIK
TABLE I11 OBSERVED A N D CALCULATED STRUCTURE FACTORS FOR P~[(C~H~)ZPCHZCHZCH~N(CH&] (SCN)(NCS)"
..
I.
r , L.
0
D,,.
2
E.
.. ',
L.
..L.
I,
I
L.
L.
..
1.
0.
L.
L,,.
6
I . L.
>
I .
6 , L.
s
..
',,.
I G
'.
I h L .
>
I.
% . I .
,
,/.
I
10
I.
sion correction was made. The final positional parameters are given in Table I and the final thermal parameters in Table 11. The observed structure amplitudes and those calculated with the data in Table I and I1 are given in Table 111. The effect of the weighting scheme was studied by repeating the last three least-squares cycles using F(1ow) of 16 and F(high) of 64 (approximately 2F0 (minimum) and 8Fo(minimum)). All the parameters changed by less than one esd except for the x and z parameters of ClO. The change in x was 0.0009 vs. an esd of 0.0007 and the change in z was 0.0007 vs. an esd of 0.0006.
Discussion The atomic numbering and some intramolecular
..L.
L,
4
distances and angles are given in Figure 1. The remaining intramolecular distances and angles together with a summary of the estimated standard deviations are given in Table IV. The palladium atom is fourcoordinated by the P and N atoms of the ligand and one S and one N from the two thiocyanate groups. Therefore, the correct formulation for the compound is Pd [(CeH5)~PCH2CHzCH2N(CH3)2](SCN) (NCS). The four donor atoms are not strictly coplanar (see Table V) although the geometry about the Pd atom can be described as square planar since the deviations are not very large. However, the two anions are not in the plane defined by the four donor atoms. The S-bonded thiocyanate is bent out of the plane by about 9.5" ; the N-bonded one is bent in the opposite direction by only 1.5".
Inorganic Chemistry, Vol. 9,No. 12, 1970 2757
AN ISOTHIOCYANATOTHIOCYANATOPALLADIUM(II) COMPLEX
TABLE I11 (Continued)
, I.
-10
I"
I , L.
1, L.
L.
bo,
L.
LO,.L.
h
L.
li,,.
I
2
,".L.
e,
L.
I
L.
I"
I
I . L.
7, 6.
L.
*I.L.
L
R.
11, L.
I
1.
Ill
