C- C 1 541 C=C 1 337 simple double
1.1.5 EXPERIMENTAL
1.1.5(a) Instrumentation
The general instrumentation and reagents used in this and succeeding chapters is described in Appendices 1 and 2 respectively.
1.1.5(b) Preparation of Compounds
2-formylpyridine thiosemicarbazone (LH)
To a hot solution of thiosemiearbazide (10.2 g, 0. 1 12 mols) in 95% ethanol (100 cm3) was added water (40 cm3). To the resulting filtered solution, 2-formylpyridine (pyridine-2- aldehyde, pyridine-2-carboxaldehyde) was added dropwise ( 1 1 .0 cm3, 0.1 16 mols) and the mixture refluxed for 2 hours. Upon cooling, yellow crystals of the title compound separated. These were filtered off and washed with water then cold ethanol and vacuum dried. Yield
17.63 g (87%) m.p. 209-212° C (c.f. Lit. = 210° C [123]).
Preparation of copper complexes
This complex was synthesised following a published procedure [64]. To a solution of LH (3.60 g, 20.0 mmols) in N,N-dimethylformamide (140 cm3) was added dropwise a solution of Cu(CH3C00)2H20 (4.03 g, 20.2 mmols) in water (150 cm3). The dark green compound which separated was filtered and washed with ethanol then diethyl ether and vacuum dried. Yield 5.02 g (83 %); m.p. 226-8° C.
[CuLF]z
CuF2·2H20 powder (282 mg, 2.05 mmols) was added slowly with constant stirring to a hot filtered solution containing LH (400 mg, 2.22 mmols) and sodium metal (60 mg, 2.61 mmols) in methanol (40 cm3). The resulting solution was boiled for 5 minutes then filtered to remove any solid NaF or unreacted CuF2. The volume was reduced on a rotary evaporator to 20 cm3 and the solution cooled in a fridge for 3 hours. The title complex separated as a dark green hydroscopic sludge and was filtered off and washed with diethyl ether then vacuum dried. Yield 264 mg (41 %).
[CuLXh (X = Cl- or Br)
These complexes were synthesised according to a slightly modified procedure for [CuLClh (after [64]). To a solution of LH (1 .00 g, 4.99 mmols) in N, N-dimethyforma.lllide (40 cm3) was added dropwise a solution of CuCl2·2H20 (0.958 g, 5.62 mmols) or CuBr2 ( 1.256 g, 5.62 mmols) in water (40 cm3). The dark green products were heated for 5 minutes, filtered and washed with ethanol and vacuum dried. Yields [CuLClhH20 1.393 g (88%); [CuLBrh 1.641 g (92%).
[CuLih
This complex was synthesised following a published method [64]. To a solution of LH (0.90 g, 4.99 mmols) in N, N-dimethylformamide (35 cm3), was added KI (16.6 g, 100 mmols) in water (50 cm3). This solution was filtered and to it was added Cu(CH3C00)2H20 (1.00 g, 5.01 mmols) in water (40 cm3). The dark green compound which formed was heated for 5 minutes then filtered and washed successively with water, ethanol and diethyl ether before beging vacuum dried. Yield 1.747 g (95%).
[CuLX] (X = NOj or CI0,4)
A slightly modified procedure (after [64]) was used for these complexes. To a hot solution of LH (1.00 g, 5.55 mmols) in ethanol (70 cm3) and water (30 cm3) was added Cu(N03)2·
�
H20 (1.309 g, 5.63 mmols) or Cu(Cl04)2·6H20 (2.07 1 g, 5.59 mmols) in water (30 cm3). The resulting dark green solution was heated for 5 minutes then left in a fridge overnight. The dark green crystalline products were filtered and given a cursory wash with cold water then vacuum dried. Yields [CuL(N03)]2 0.422 g (25%); [CuL(Cl04)]2 1. 104 g (58%).[ ( CuL hS 0 4(HzO) 2lH2 0
To a hot solution containing LH (30 1 mg, 1 .67 mmols) and sodium metal (47 mg, 2.04 mmols) in ethanol (40 cm3) was added CuS04·5H:.20 (417 mg, 1.67 mmols) in water (10 cm3). The green precipitated was filtered and washed with water, ethanol then diethyl ether. Yield 288 mg (54%).
[ C u L X ] z (X = NCS· or Nj)
Upon addition of KSCN ( 1 65 mg, 1.70 mmols) or NaN3 (140 mg, 2. 15 mmols) in water (10 cm3) to Cu(CH3C00)2H20 (322 mg, 1.66 mmols) in methanol (30 cm3) a milky green solution formed. To this was added a solution of LH (296 mg, 1 .64 mmols) in methanol (30 cm3). The resulting dark green solution was refluxed gently for one hour then the green solids were filtered off and washed successively with water, methanol and diethyl ether then vacuum dried. Yields [CuL(SCN)]2 384 mg (77%) m.p. 212-4. C; [CuLN3hH20 386 mg (79%).
[CuL( CN)h
A solution of [CuL(CH3C00)]2 (302 mg, 1.00 mmols) was briefly boiled in water (100 cm3) then filtered. While this was still hot a solution of NaCN (53 mg, 1.08 mmols) in water (10
washed with boiling water then vacuum dried. Yield 94 mg (33% ).
[Cu (LH)FhF2
To a solution of 3 M HF (7 cm3) (in a plastic beaker) was added [CuL(CH3COO)h (260 mg, 0.86 mmols) with heating to form a saturated solution. This was then filtered to remove any undissolved matter and put aside for 6 weeks until the solution had gone to dryness. The dark green/black compound was put on a vacuum line for 1 day to remove any acetic acid present. Yield 175 mg (72%).
Following the general procedure used by Bingham et al. [64] [CuL(CH3C00)]2 (302 mg, 1.00 mmols) was added to a 2.6 M CF3COOH solution (25 cm3) or a 2.0 M H2S04 solution (30 cm3) with heat. The resulting emerald green solutions were filtered immediately then left for 1 day. The dark green crystals which separated were removed from solution and given a cursory wash with diethyl ether. Yields [Cu(LH)(CF3C00)]2(CF3C00)2 1 82 mg (39%); [Cu(LH)(S04)]2 1 84 mg (54%).
[ C u (L H ) X h X 2 (X = CI-, Br· or I·)
To [CuL(CH3C00)]2 (320 mg, 1 .06 mmols) in water (20 cm3) was added the appropriate concentrated acid (10 cm3) and the mixture heated for 5 minutes. The emerald green (X = Cl and Br) or red/orange (X = I-) precipita!�S were filtered and washed with acetone. Yields [Cu(LH)Cl]2Cl2·2H20 315 mg (89%); [Cu(LH)Br]2Br2·2H20 407 mg (91 %); [Cu(LH)Ihi2 483 mg (92%).
[ C u ( L H ) X2l (X = NOj or Cl04)
To a Y.> M solution of the appropriate acid, HX (10 cm3), solid [CuL(CH3COO)h (155 mg, 0.51 mmols) was added to give a green solution. After a very cold night 10 weeks later both solutions deposited green/blue crystals which were given a cursory wash with the appropriate
Y3 M acid. The perchlorato complex was found to be unstable when heated and may explode. Yields [Cu(LH)(Cl04hH20}2H20 66 mg (28%); [Cu(LH)(N03hH20J 127 mg (65%).
[Cu (I) (LH)I] ·
t
H 2 0To Cui (400 mg, 2. 10 mmols) was added Lii (2.0 g, 14.94 mmols) in the minimum volume of hot ethanol (15 cm3) required to dissolve most of the Cui. This was decanted into a flask and LH (384 mg, 1.27 mmols) in ethanol (50 cm3) was added dropwise. The mixture was then refluxed under nitrogen for 2 hours. The resulting brown product was washed successively with an ethanolic Lii solution (10 cm3), hot ethanol and diethyl ether then vacuum dried. Yield 489 mg (96% ).
[Cu(I) (LH) (CI04)]
An attempt was made to isolate a copper(!) thiolato complex with LH. To Cu(Cl04)2·6H20 (373 mg, 1 .00 mmols) in ethanol ( 1 0 cm3 ) was added a solution containing pentafluorothiophenol (0.27 cm3, 2.00 mmols) in ethanol (5 cm3). The resulting yellow gel was heated briefly and was then added slowly with heat to a solution of LH (21 6 mg, 1.20 mmols) in ethanol (20 cm3). A deep red/brown solution containing a red precipitate formed which was then refluxed overnight. An orange/red powder which analysed as the title complex was filtered off and washed with hot ethanol, hot chloroform then diethyl ether and vacuum dried. Yield 323 mg (94%).
l.l.S(c) X-ray Crystallography
Nine single-crystal X-ray crystallographic structures were determined in this work. Six of these were collected on an Enraf-Nonius CAD-4 diffractometer at Massey University and the remaining three were collected at Canterbury University by Dr Ward Robinson on a Nicolet R3M diffractometer.
As the general procedure for the data collection on the CAD-4 was similar in all six cases, a more detailed description of the collection parameters is given only for the first structure. Tables summarising the crystal and data collection parameters for all structures are given in their corresponding experimental sections.
l.l.S(d) Data collection procedure for Di-11-trifluoroacetato-bis [(2-
formylpyridine thiosemicarbazone)copper (Il)] B istrifluoroacetate.
The title compound was synthesised as described in section 1 . 1.5(a). A crystal of approximate dimensions 0.060 x 0.015 x 0.004 cm was mounted on a glass fibre using 'Araldite' adhesive.
Twenty-five initial reflections were located using the routine 'search' and an approximate cell was calculated. A thin-shell of data was collected (8 30-40.) and from this, twenty-five strong reflections with the following additional criteria were chosen to calculate the cell dimensions.
1 Phi values to cover ±180·.
2 Chi values distributed within the range ±4o·. 3 Largest possible values for h, k and l
The refined cell dimensions are: a = 9.601 5(7), b = 10.8374(10), c = 8.8 105(16)A; a = 100.706(1 1), � = 1 17.064(10) and y = 80.877(7)". For a cell volume of 799.3 A3 and a molecular weight of 939.6 a.m.u. (C22H16Cu2F12NsOsS2) the density was calculated to be 1.952 g cm-3 for one formula weight in the unit cell. Diffraction symmetry was consistent with the triclinic crystal class (space group P 1 or PI). Final analysis proved P I to be the correct space group.
The intensity data were collected on an Enraf-Nonius CAD-4 diffractometer with Cu-Ko: radiation (� (Cu-Ku) = 38.36 cm-1) using the ro/28 scan technique (Smax = 75"). The ro scan is given by eo = A + BtanS, where A is a constant dependent on the crystal mosaic spread and the divergence of the primary beam, and the Btane term allows for reflection widening due to a1 - a2 splitting at high theta angles. Values used in this case were A = 0.80 and B = 0.142. The scans were automatically extended by 25% at each side of the peak to afford background measurements.
The width of the variable aperture of the detector is given by Apt = A + BtanS. For this structure A = 1 . 70 and B = 1.20 were used. The vertical size of the aperture is fixed and consists of a manually insertable slot of height 4 mm.
The initial intensity measurements were made by a fixed speed 'prescan'. If the relative cr(F2)* JF2 of the prescan measurement is not equal to or less than a specified acceptance parameter, then the reflection is considered unobserved and a final, slower scan is not undertaken. The speed of the final scan is calculated on the basic prescan and a second cr(F2)JF2 which is required for the final measurement, the maximum time on the final scan being set by the operator. For this structure initial intensity measurements were made by a fixed speed prescan of (20/3)"/min with the relative cr(F2)JF2 for the prescan acceptance parameter set at 0.80. The final scan cr(F)JF2 was set at 0.018 with a maximum scan time of 100 s.
* cr(I) = (INT + 4 (BGL + BGR))¥-l, where INT represents the total count and BGL and BGR are the left and right background counts respectively.
Three standard reflections were monitored at hourly intervals so that scaling of the final data could be carried out should crystal decomposition occur. For this data set, the total loss of intensity was 12.5%; minimum and maximum corrections for anisotropic decay were later determined as 0.9974 and 1. 1902 respectively.
The same three reflections were used to check that the scattering vectors did not deviate more than O.os· from their calculated positions. No such deviation occurred for this structure.
A total of 3504 reflections were collected for the hk l range: - 12--710, - 13--713, 0--7 1 1. After averaging equivalent measurements, the data set consisted of 297 4 reflections for which p2 >
3cr(f2). The raw intensity was calculated from the expression:
I raw where ATN NPI
c
B R 20. 1 1 66 x ATN ( C - R x B ) = NPI= attenuation factor (= 12.34 - automatically inserted if the count rate
exceeded 10 000 counts per second during the scan)
= ratio of fastest possible scan rate to scan rate for the actual measurement = total count
= total background count
= ratio of scan time to background counting time (2.0 for CAD-4)
The standard deviations in the observed intensities are given by;
cr(I) = 20. 1 1 66 x ATN ( C + R2 x B ) Y2
NPI
For all nine structures Lorentz and polarisation corrections were made to the data. Corrections were also made for absorption.
For numerical (analytical) absorption corrections [124, 125] a precise description of the crystal in terms of its size and the identification of the crystal faces is needed. The maximum dimensions of the crystal along each of the crystallographic axes are used to determine a relative grid density which in turn is used in a Gaussian integration. The path length travelled within the crystal by the beam reflected from each infinitesimal element of volume is calculated and then these results are integrated over the entire volume of the crystal. In this way the absorption correction for each reflection is obtained. Individual numerical corrections are then applied to the intensity data.
For empirical absorption corrections [126] a set of four reflections with Chi near 90° is chosen. An accurate scan in Phi over the range 0 to 360° is then carried out on the diffractometer for each reflection. Interpolation of the data for each curve enables intensities at 10° intervals to be
calculated and then averaged about phi of 0°. The maximum intensity for each curve is found and this is considered to be 100% transmission. Trans!!'ission factors for other points on the curve are calculated relative to the maximum transmission and then averaged for all curves. Absorption corrections can thus be applied when crystal faces can not readily be indexed or crystals are mounted in capillaries.
For this data set numerical absorption corrections were applied using the displayed faces
{ 0 I 0 } , { I 0 0 } , { 0 1 0 } , { 1 0 0 } , { 0 0 I } and { 0 0 1 } with a grid size of 4 x 4 x 8.
:Minimum and maximum transmission coefficients were 0.2328 and 0.7841 respectively.
Tables 1 . 1 . 1 4 and 1 . 1 . 1 5 summarise th� relevant crystal and data collection parameters respectively.
The copper position was located from a Patterson map and a structure factor calculation based on this site with a fixed isotropic temperature factor (U = 0.04) for copper returned a residual of 0.60. The remaining non-hydrogen atoms were located on the heavy atom electron-density map. Three cycles of least-squares with all parameters allowed to refine assuming isotropic thermal motion returned an R-factor of 0. 17. Inspection of a difference map revealed sites for all hydrogen atoms as well as showing disordered sites for fluorine atoms of both trifluoroacetate groups. Four major positions for each fluorine (with the indicated occupancy given in the appropriate table on the microfiche) were included after fixing the isotropic thermal parameters at 0.04 and refining the occupancy. This resulted in an R-factor of 0. 14. Hydrogen atoms were included at calculated positions in these computations. A further least-squares cycle with the copper and sulphur refined assuming anisotropic thermal motion gave an R factor of 0. 1 0.
For the fmal least-squares cycle, the six highest occupancy fluorine positions and all other non hydrogen atoms were refined assuming anisotropic thermal motion and converged to values of 0.0707 and 0.08 16 for R and Rw respectively. The function minimised was Lw(IF01 - 1Fcl)2 for the 3 19 parameters and 2974 data for which F2 > 3cr(F2) with the weight, w, being defined as
l.OOO/(cr2(F) + 0.017 134 F2). The largest parameter shift per estimated standard deviation, (esd) was 0.46.The atomic scattering factors and anomalous dispersion coefficients for copper for this and all other structures in this thesis were taken from [127]. The four highest peaks in the final difference electron density map were in the range 1. 1 1 - 0.57 e A-3, and these were associated with the residual electron density around the copper and sulphur atoms.
Final atomic parameters and the observed and calculated structure factors are on the microfiche in the pocket inside the back cover of this thesis. The bond length and bond angle data are in Tables 1. 1.2 and 1 . 1.3 respectively.
Compound: Colour: Formula: Formula weight: Space group: il,: .Q: a.: �: y. V: Z: Crystal faces: Crystal dimensions: Jl (Cu-Krx): F(OOO): ([Cu(LH) (CF3C00)]2(CF3C 0 0 )2) CRYSTAL DATA
Di-J.L-trifluoroacetato-bis[ (2-formy lpyridine thiosemicarbazone) copper(II)] Bistrifluoroacetate Green C22H 16Cu2F 12NsOsS2 939.6 a.m.u. P I 9.6015(7) A 10.8374(10) A 8.8105(16) A 100.706(1 1)" 1 17.064(10)" 80.877(7)" 799.3 A3 1 1 .952 g cm-3 { 0 1 0 } , { l O O } , { 0 1 0 } , { 1 0 0 } , { 0 0 1 } , { 0 0 1 } 0.060 x 0.015 x 0.004 cm 38.36 cm-1 462
Parameters Associated with Data Collection
Radiation used:
Graphite monochromator used: Incident beam collimator (diameter):
ro scan angle:
Horizontal aperture width: Vertical aperture height: Scan type:
Prescan speed: Prescan acceptance; relative cr(F2)JF2 required: Final scan acceptance cr(F2)JF2:
Maximum time limit for final scan: Intensity control frequency:
Orientation acceptance; maximum deviation
Cu-Ko:
(A =
1 .541 8 A) no 1.3 mm (0.80 + 0.142 tan er ( 1 .70 + 1 .20 tan 8) mm 4 mm 0.8 0.0 1 8 lOO s 3 600 sof any scattering vector from its calculated position: 0.08° 8 Range:
Total number of reflections in data set:
1-7Y 3 504
Observed data criterion: 2 97 4 unique reflections with p2 > 3cr(F2)
1. 1.5(f) Data collection procedure for Aqua(2-formylpyridine thiosemicarbazone diperchloraro)copper(II) Dihydrate.
The title compound was synthesised as described in section 1.1.5(a). A crystal of approximate dimensions 0.045 x 0.025 x 0.020 cm displayed faces of the forms { 1 1 0 } , { I 1 0 } , { i I 0 } , { 1 i 0 } , { 0 1 1 } , { i 0 1 } , { 0 I 1 } , { 1 0 1 } and { 0 1 I } . Cell dimensions determined from a least-squares refinement of the setting angles of 25 reflections are: g_ = 1 2.9601(6), Q_ = 9.7623(4), _g_ = 14.9950(10) A and � = 1 1 1 .580(5)". For a cell volume of 1764.2 A3 and a molecular weight of 496.8 a.m.u. (C7H14Cl2CuN40 nS) the density was calculated to be 1 .870 g cm-3 for four formula weights in the cell. Systematic absences (h. 0 l, l = 2n + 1; and 0 .k 0, .k = 2n + 1 ) established the space group as P21/c. A total of 4032 reflections were collected on an Enraf-Nonius CAD-4 diffractometer with Cu-Ka:. radiation (j..t (Cu-Krx) = 59.81 cm-1) using the ro/20 scan technique (0max = 75.0.). The h k l limits were: - 1 6 -7 15, 0 -7 12, 0 -7 18.
The intensities of three standard reflections were monitored at 2 hourly intervals during the data collection. The total loss of intensity was 4.8% so corrections for anisotropic decay were applied, minimum and maximum corrections being 0.9836 and 1.0586 respectively.
Analytical absorption corrections were applied [ 125, 125 ] , minimum and maximum transmission coefficients being 0.0666 and 0.3775 respectively.
The copper atom located from the Patterson synthesis, yielded a residual of 0.57 after two cycles of refinement over one quarter of the unit cell. The subsequent electron density map, based on the calculated phase of this copper site revealed the positions of the two Cls the S and four peaks designated as N. A least-squares refinement returned an R factor of 0.36. All non hydrogen atoms were located from a series of electron density and least-squares calculations to give R = 0.1 0. A difference electron density map revealed peaks within bonding distance of Cl(2). These were included as one quarter weighted oxygens. All hydrogen atoms were located, those in the pyridine and on C(6) being fixed at 1 .08 A.
The final least-squares refinement cycle converged to values of 0.0586 and 0.0725 for R and
Rw respectively for the 250 parameters and 3 247 data for which p2 > 3cr(F2). The function
minimised was 2:w(IF01 - 1Fcl)2 with the weight, w, being defined as 1 .000/(cr2(F) + 0.1 146 F2). The largest parameter shift per esd of 0.4 was associated with a disordered perchlorate oxygen. The three one quarter weighted perchlorato oxygen atoms and the hydrogen atoms were refined with isotropic thermal parameters. All other atoms were refined assuming anisotropic thermal motion.
The highest peak of 0.60 e A-3 in the final difference electron density map was associated with the residual electron density around the copper atom.
Final atomic parameters and the observed and calculated structure factors are on the microfiche in the pocket inside the back cover of this thesis. The bond length and bond angle data are in Tables 1 . 1.2 and 1 . 1 .3 respectively.
Compound: Colour: Formula: Formula weight: Space group: gJ,: .Q: �= �: V: Z: Crystal faces: Crystal dimensions: !l (Cu-K0): F(OOO): ([Cu(LH) (CI0 4hH20] ·2H20 CRYSTAL DATA
Aqua(2-formy lpyridine thiosemicarbazone diperchlorato )copper(ll) Dihydrate Green C7H14C12CuN40uS 496.8 a.m.u. P21/C 12.9601 (6) A 9.7623(4) A 14.9950(10) A 1 1 1.580(5)" 1764.2 A3 4 1 .870 g cm-3 { 1 1 0 } , { l l O } , { I I O } , { l i O } , { 0 1 1 } , { I O l } , { O i l } , { 1 0 1 } , { O l i } 0.045 x 0.025 x 0.020 cm 59.8 1 cm-1 1004
Parameters Associated with Data Collection
Radiation used:
Graphite monochromator used: Incident beam collimator (diameter): ro scan angle:
Horizontal aperture width: Vertical aperture height: Scan type:
Prescan speed: Prescan acceptance; relative cr(F2)fF2 required: Final scan acceptance cr(F2)fF2: Maximum time limit for fmal scan: Intensity control frequency:
Orientation acceptance; maximum deviation
Cu-Kcx
(A =
1.5418 A) no 0.8 mm (0.80 + 0.14 tan er ( 1 .70 + 1.20 tan 8) mm 4 mm ro/28 (20/3)"/min 0. 8 0.0 1 8 100 s 7 200 sof any scattering vector from its calculated position: 0.08· 8 Range:
Total number of reflections in data set:
1-75. 4 032
Observed data criterion: 3 247 unique reflections with F2 > 3a(F2)
CHAPTER 2
TERNARY S AND N DONOR ATOM COPPER COMPLEXES OF L·