Nitrophenylmethane and nitromethane complexes of copper(I) with tertiary phosphines or heterocyclic nitrogen donors and some of their oxidation products

J. im~re nuct Chem., 1977, Vo[. 39, pp 275-280. Pergamon Press. Printed in Great Britain

NITROPHENYLMETHANE AND NITROMETHANE COMPLEXES OF COPPER(I) WITH TERTIARY PHOSPHINES OR HETEROCYCLIC NITROGEN DONORS AND SOME OF THEIR OXIDATION PRODUCTS N. MARSICH and A. CAMUS Institute of Chemistryand CNR Center, University of Trieste, 34127Trieste, Italy (Received 14 April 1976)

Abstract--Mixed copper(l) complexes with nitrophenylmethane (NPMH) of the following stoicheiometries Cu(NPM)L2 (L = PPh3, pyridine; L-L = bis(diphenylphoshino)methane,2,2'-bipyridine),(CuNPM)2 (L-L)3 (L-L 1,2-bis(diphenylphosphino)ethane) and [Cu(L-L)2]NPM (L-L= 1,10-phenanthroline) have been isolated and characterized. The correspondingphosphine complexes of the nitromethane are also described. In the complexes of the nitrophenylmethanecleavage of the PhCH = group occurs easily, while the NO~ group remains bonded to the copper atom as nitrite ligand. INTRODUCTION

Mixed Cu(I) complexes are easily obtained by the reaction between arylorganocopper(I) and active hydrogen compounds in the presence of mono- and bi-dentate ligands of tertiary phosphines or heterocyclic nitrogen donors type. The active hydrogen compound enters the complex as conjugated base, while the arene corresponding to the parent organocopper compound forms in high yield[I,2]. In a recent paper we have described some mixed Cu(I) complexes of dinitrophenylmethane (DNPMH)[2]; now we report the isolation of analogous complexes with nitrophenylmethane (NPMH) and nitromethane (NMH) and the thermal and oxidative decomposition of the first series of derivatives. To our knowledge Cu(l) complexes with these ligands are not known in literature, only few examples of copper(II) derivatives being reported, i.e. some planar tetracoordinated complexes with NPM[3] and some cationic mixed complexes [(Cu(Phen)2NM]+ [4]. RESULTS AND DISCUSSION

(A) Preparation and characterization o[ the complexes Complexes of three different stoicheiometries have been obtained by direct reaction between the active hydrogen compound (BH) and o-tolylcopper in the presence of mono- or bi-dentate ligands (L,L-L), although the reagents were in a 1 : 1 : 2 ratio 6) CuBL2, CuB(L-L) L=triphenylphosphine(PPh3); L-L = bis(diphenylphospino)methane (DPM), 2,2'bipyridine (Bipy). (ii) (CuB)2(L-L)3 L - L = 1,2-bis(diphenylphosphino)ethane(DPE). (iii) [Cu(L-L)2]B L-L = 1,10-phenanthroline (Phen). The stoicheiometries of the complexes are those already found for the DNPMH derivatives, except that of Bipy, which was of type (ii). The isolated compounds are listed in Table 1, together with their elemental analyses, molecular weights and conductivities. A stable dark violet complex of approximate formula [Cu(Phen)2]NM is also formed. We were unable to isolate it in a pure state under anhydrous conditions, but excellent analyses were obtained for the tStilbene and low amount of benzaldehyde were detected in mother liquors by GLC. CThe DNPMH and NMH derivatives do not give this reaction. Cu(PPh~hNM showed a completely different behaviour in hot acetone [7].

hydrated form [Cu(Phen)2]NM.2H20, starting from hydrated phenanthroline. Complexes with monodentate N-bases, like pyridine, picoline, etc. are unstable at room temperature for both series and so is the Bipy derivative of the NMH series. All the complexes in Table 1 are diamagnetic. Their stability towards heating and oxidation decreases in the order: DNPMH >>NPMH > NMH derivatives, that is with the decreasing acidity of the conjugated bases. The conductivity decreases in the same order. In particular the electrolytic character of the Phen complexes diminishes markedly, although both the NPMH and NMH derivatives undergo exchange reaction with NaC104 to give the known [Cu(Phen)2]C104[5]. Like for the DNPMH series, the above complexes are monomers in solution, except for the Cu(DPM)NPM derivative, which has a molecular weight notably higher than that calculated for the monomer and exists probably as a dimer in the solid state. As for the Cu(DPM)NM, the complex reacts with chlorinated solvents and therefore the measured molecular weight is not reliable. The IR spectra of the above phosphine derivatives suggest that the -rNO2 group is O,O-chelated to the metal, like in a - nitroaacinitrotoluenato - bis(triphe, nylphosphine)Cu(I) [6] and in the reaction product of acetone with Cu(PPh3)2NM [7]. In fact the vC=N and vNO2 frequencies observed for the above complexes (Table 2) are in good agreement with those of sodium nitromethanate[8] and phenylnitromethanate[3], respectively. The attribution of the other -NO2 absorptions was not attempted, owing to interfering ligand frequencies. The IR spectrum of [Cu(Phen)2]NPM, where the nitroderivative moiety acts as anion, shows a feature largely different from that of the phosphine complexes. In this case the main bands of the NPM , attributed by comparison with the spectrum of [Cu(Phen)2]CIO4, appear at 1487 s (splitted), 1225 s, 1162 s (with shoulders), 980 s, 698m, 510mwcm t. Also the CuBipyNPM complex shows very similar frequencies (1495 m, 1483 m, 1224 s, 1150 s (splitted), 977 s, 698 m, 509 mw cm %. (B) Reactions of the complexes of NPMH Thermal decomposition. When the complexes Cu(PPh3)2NPM and Cu(DPM)NPM are refluxed in toluene, acetone or other solvents, a cleavage occurs, with removal of the PhCH=t group and formation of the diamagnetic and non conducting compounds Cu(PPh3)2NO2 and Cu(DPM)NO2.~ The former complex

Blue-violet

162-3.5

170-2

181-2

~ 185-7 [195-200 darkens gradually above 1200

<98 dec.

< 130 dec.

~-137-5 [206-9

m.p.

69.3 (69.29) 66.6 (66.48) 68.4 (68.56) 62.3 (61.47) 66.8 (66.61) 57.5 (57.74)

H

5.30 (5.31) 4.11 (3.%) 4.92 (4.98) 4.47 (4.76) 5.39 (5.31) 4.14 (4.26)

5.09 (5.01) 4.65 (4.83) 3.90 (3.97)

Analysis:

71.5 (71.31) 65.3 (65,80) 58.1 (57.38)

C

1.65 (1.76) 12.5 (12.51) 2.03 (2.16) 2.25 (2.76) 1.85 (1.94) 13.4 (13.47)

1.95 (1.93) 2.5 (2.40) 11.8 (11.81)

Found N

7.6 (7.97) 11.5 (11.35) 9.6 (9.80) 12.66 (12.51) 8.8 (8.81) 12.35 (12.22)

8.7 (8.77) 10.6 (10.88) 17.7 (17.86)

(calcd)% Cu

Dec.

0.8

0.6

33.5 20.5

Dec.

9.7

<0.1

DCE

Low sol.

3.8

0

116 74

Dec.

20.8

-0

Low sol.

8.4

Low sol.

124 60

115

20.7

Low sol.

Am ~-~ cm 2 mole-Jr acetone MeOH

790 (0.8) 478 (1.2) 440 (1.3) 1346 (1.4) 1389 (1.04)

Dec

685 (0.'/5) 754 (2.8)

560 648 508 1442

Low sol. Low sol. Low sol.

15955

584

724

Calcd.

1702 (1.4) Low sol.

Low sol.

713 (1.04) 759 (1.4)

M.W. found DCE b e n z e n e (% w/w)

t20°C, 10-3 M. ~tFrom toluene crystallizes with 1.5 molecules of solvent (C~o2~Hg~N20,P6Cu2: calcd: C, 71.05; H, 5,58; N, 1.62; Cu, 7.33; toluene 7.94; Found: C, 71.5; H, 5.33; N, 1.47; Cu, 7.3; toluene 7.7%). §Turns immediately to blue-violet in moist solvents. yrhe calculated value for the complex crystallized with 1.5 molecules of benzene is 1712. ~tCould not be recrystallized without decomposition.

[(Phen)2Cu]NM.2H20

White

Pale yellow

DPMCuNM"

(DPE)3(CuNM)2

White

(PPh3hCuNM

Amaranth11

[(PhenhCu]NPM

Red-brown

BipyCuNPM

White§

White

DPMCuNPM

(DPE)~(CuNPM)2$

White

Colour

(PPh3)2CuNPM

Complex

Table 1. Cu(I)mixedcomplexesofnitrophenylmethaneandnitromethane

>

("3

Z

Nitrophenylmethane and nitromethane complexes of copper(I}

E

z= z ,tD

~Z z

z

e'~

z~ z

E

¢.)

z

z g

E

E

E

g

,g d' z z

M

c5 z

~,

277

is monomeric in chloroform or benzene, the latter dimeric. Their IR spectra show that the -NO2 group is coordinated to the copper atom as nitrite. In fact strong broad absorption bands are present in the 1200cm region (at about 1210 cm ~j for the PPh3- and at ll90cm ' for the DPM-derivative), which is characteristic of v, N()~ in coordinated nitrites [9, 1012 The absence of other main bands in the 5315-1260cm ' region excludes the O,Ochelating or bridging form for the nitrite[15], while N,O-bridging groups may be present[52]. The spectra are very similar to those of the corresponding nitrate complexes[13, 14], which show the expected shirtings of the v, NO,. to higher frequencies (5275 and 1289 cm ') and of the weak 6NO2 to lower frequencies (from ',342, 840 cm ' to 809, 812 cm ~, respectively). The spectra of the triphenylphosphine derivatives of both series are practically coincident in the 1150-200 cm ' region, while those of the DPM complexes are considerably different. The spectrum of Cu(DPM)NO2 is similar to those of Cu(DPM)C1 and Cu(DPM)Br, crystallized from aromalic solvents [151. Oxidation reactions. While the complexes with plaosphines are ralber stable to autoxidation, moist Bipy and Phen derivatives react irreversibly with molecular oxygen to give Cu(lI) complexes. As already found in the DNPMH series the Bipy derivative is oxidized more easily that that of Phen. The reaction rate in different media follows the solubilities of the compounds, decreasing in the order: chlorinated solvents>acetone= alcohols>hydrocarbons. However, in the DNPMH series this ligand is still present in the oxidation prodncts, while in the NPMH series cleavage of the PhCH = group occurs$ and only the NO2 group enters the new complexes as nitrite. Three different copper(II) complexes have been isolated among the oxidation products of CuBipyNPM in methanol. The main product, (A), has rough formula Cm'~H,oN:~O:~-4Cu, thus is probably a binuclear complex. As first we considered it as [CuBipy(OH)]2(NO2)2.MeOH, analogous to the known compound [CuBipy(OH)]2(NO3)2[16], since both complexes gave the same percblorate [CuBipy(OH)l~(CIO4)~ and since the compound [CuBipy(OH)]2(NO:):4H20, obtained by a synthesis parallel to that of the niltrate derivative[17], gave (A) by crystallization from hot methanol. However, while the IR spectrum of the hydrated form is in good agreement with the literature data for complexes of the type [CuBipy(OH)]f +[58], the spectrum of (A) is not, and furthermore suggests the presence of different kinds of NO2 groups (strong broad bands with shoulders at about 1230 and 1550 cm ~). Other main absorption bands are present at about 1374s,br 904 m, 542 m,br and 330 m,br cm ', besides the peaks due to coordinated Bipy. The visible spectrum presents a single broad peak at 642 nm in methanol.§ GLC shows the

.<

tThe ~.,NO:~ are probably obscured by the absorption of the ligands in the 1430cm ' region. ~Benzaldehyde and methyl benzoate were detected in mother liquors by GLC §Among the known copper(lI) complexes with Bipy and --NO2 or -NO~ groups, the only compound with a similar absorption (650 nm) is Cu[~ipy(ONO)2[19]. Its maximum, however, shifts to 675 nm in water, while the absorption of (A) is unchanged in this solvent. [CuBipy(OH)]dNO2)2 and 5CuBipy(OH)]2(NO0~ have absorption maxima in water at 620 and 617 rim, respectively.

278

N. MARSICH and A. CAMUS

presence of one molecule of MeOH. Thus a possible formulation for (A), in better agreement with the analytical data, is [Cu2(Bipy)2(NO2)3(OCH3)].Anyway the X-ray crystal structure is in progress. The formation of the [CuBipy(OH)]:(ClO4)2t can be explained assuming a partial cleavage of the molecule by aqueous NaCI04. Actually the reaction rate is slow and the yield in perchlorate is poor. A second complex, (B), identified as [Cu(Bipy)2(ONO)]NO2 by comparison with an authentic sample, was isolated in low yield from the mother liquors of (A). The similarity of the IR spectra of (A) and (B) suggests that the NO2 groups in these complexes are in the same structural feature. Both complexes show a negligible conductivity in nitrobenzene. The oxidation reaction of CuBipyNPM is faster, when an equimolecular amount of Bipy is added. In this case a third complex, (C), identical with [Cu(Bipy)2(ONO)]NO3121-23] was isolated as main product, after a prolonged reaction time. The correlations among oxidation products and other authentic samples are summarized in Scheme 1. The rate of oxygen uptake by the [Cu(Phen)2]NPM in methanol is much slower than that by the CuBipyNPM complex, probably owing to their different stoicheiometries. Addition of NPMH increases markedly the oxidation rate of [Cu(Phen)2]NPM. Two different complexes, (D) and (E), were isolated among the autoxidation products and identified as [Cu(Phen)2(ONO)]NO2 and [Cu(Phen)2(ONO)]NO3. MeOH, by comparison with authentic samples. In the majority of the runs, however, analyses, IR and powder spectra suggest that the isolated products are mixtures of the two above compounds. It is interesting to note that pure [Cu(Phen)2(ONO)]NO2 is not transformed into (E) by molecular oxygen in methanol. tin its IR spectrum the bands of (A) at 1234, 1155, 330cm-1 have disappeared, while the band at 542cm-1 is shifted to 510cm-I. The spectrum is different from those reported in literature for the monohydrate[18,20].

Furthermore it is much more stable than the corresponding Bipy derivative and only by refluxing in MeOH dissociates partially one Phen ligand, to give CuPhen(ONO)2. Another product, (F), was isolated after hydrolysis of the mother liquors of (D) and (E) and identified as [CuPhen(OH)]2(NO02'2H20. Scheme 2 summarizes the correlations between the oxidation products of [Cu(Phen)2]NPM and authentic samples, many of which are new. EXPERIMENTAL Preparation of the mixed Cu(I) complexes The mixed Cu(I) complexes listed in Table 1 were prepared by addition at first of NPMH [27] or freshly distilled NMH and then of the other ligands to a stirred suspension of o-tolylcopper[28]. The conditions have been already described for the DNPMH series [2]. Yields (calculated on the basis of the produced toluene) were always higher than 85% and often almost quantitative. All the complexes are easily soluble in chlorinated solvents but react slowly with them. Only the phosphine derivatives could be recrystallized rapidly from these solvents by addition of ether. Bipy and Phen derivatives and the Cu(DPM)NM complex could not be recrystallized unchanged from these or other common solvents. Reactions of the NPMH complexes Thermal decomposition of Cu(PPh3)2NPM. 0.5g of this complex dissolved completely by refluxingin toluene (25 ml) for few minutes and a white solid precipitated almost immediately. Recrystallization from hot toluene gave transparent needles, which became white by drying in vacuo m.p. 214--6°C (dec). Cu(PPh3)2NO2calcd2 C, 68.18; H, 4.77; N, 2.21; Cu, 10.02;M.W. 634; Found: C, 68.1; H, 4.79; N, 2.2; Cu, 10.2%;M.W. 632 (0.9% w/w in CHC13);669 (1.0% w/w in benzene). Thermal decomposition of Cu(DPM)NPM. The reaction is analogous to that above described. Recrystallization from methylene chloride and ether yielded white silky needles, m.p. 182-4°C(dec). Cu(DPM)NO2calcd.: C, 60.79;H, 4.49;N, 2.84;Cu, 12.86; M.W. 494: Found: C, 60.8; H, 4.50; N, 2.8; Cu, 12.5%; M.W. 1054 (0.9% w/w in CHCI3). Oxidation of CuBipyNPM. (A) Molecular oxygen was bubbled into a suspension of the complex (0.82g) in methanol (30 ml) at room temperature. The red solution turned slowly to green, while the solid dissolved almost completely.The reaction was carried on

[CuBipy(OH)]2SO4.5H20 [24]

I Ba(NO2)2"H20 \ [CuBipy(OH)]2(NOD2.4H20

[CuBipy(OH)]2(NO3)2 [16, 17] ~

×I×MeOH/ether -~ A

CuBipyNPM

02 MeOH

f,

NaCIO4

CuBipy(ONO)2 [ 19] T MeOH/ether

II

2

> [Cu(Bipy)2(ONO)]C104 [21]

l

CuSO,.5H~O + Bipy + Ba(NO2)2-H20 :

NaCIO4

B = [Cu(Bipy)2(ONO)]NO2 [21]~

> C = [Cu(Bipy)~(ONO)lNO~ [21,221

Bipy

1

> [CuBipy(OH)]2(CIO4)2[18,20]:~

:

1

Cu(NO3)2.3H20 + Bipy + NaNO2 [23] 1

:

2.2

:

l

Scheme 1 :~Thedifference between the IR spectra of our complexes and those reported in literature for hydrated forms may be attributed to the pressure in the latter compounds of covalent hydration rather than water of crystallization[25].

Nitrophenylmethane and nitromethane complexes of copper(l)

279

CuSO,.5H:O + Phen + NaNO2 1

:

2

:

2

l

Na( IO 4

D = [Cu(Phen)2(ONO)INO2

/

:~ [Cu(Phen}2(ONO)]CIO4 [261

hot M e O H NaC[() 4

CuPhen(ONO)2 [Cu(Phen),l NPM

,?2

E = [Cu(Phen)~(ONO)]NO3.MeOH

~×MeOH __------~

Cu(NOO:-3H20 + Phen ~-NaNO~

MeOH

1

F = [CuPhen(OH)]ffNO~)2-2H20

T

NaCIO a

:

2

:

1

[CuP hen(OH)]2(CIO4)2[ 18] [CuPhen(OH)]dCIO,)~.H20 [24a]

[CuPhen(OH)I~SO~-5H20 + Ba(NO,),.H~O 1

as long as oxygen uptake ceased (18 hr) and the little green-blue residue was filtered off. Treatment of the deep green solution with ether gave a powder of the same colour, (A), which was recrystallized from MeOH. Cu2BipydNO2)dCH30) calcd.: C, 41.44; H, 3.15; N, 16.11; Cu, 20.88; MeOH 5.26; Found: C, 41.1; H, 3.00; N. 15.9; Cu, 20.9; MeOH, 5.5%. MeOH was determined by GLC, in a nitromethane solution of the complex, favouring its solubilization by addition of Bipy. The brown colour of the solution suggests that a reaction of (A) has occurred under these conditions. 0.3 g of (A), dissolved in hot methanol and treated with excess of NaCIO,, gave, after many hours, violet needles, which were filtered washed with methanol and dried in vacuo. [CuBipy(OH)]2(CIO4)2 calcd.: C, 35.72; H, 2.70; N, 8.33; Cu, 18.90; Found: C, 35.64; H, 2.66; N, 8.3; Cu, 19.10%. (B) Further concentration of the mother liquors of (A) gave a pale green product (B) with the visible and IR spectroscopic characteristics of the authentic complex [Cu(Bipy)2(ONO)]NO2. The product changed substantially by recrystallization from MeOH/ether, giving dark green crystals, the IR spectrum and analytical data of which, are in agreement with those of CuBipy(ONO)dl9]. CuBipy(ONO)2 calcd: C, 38.53; H, 2.59; N, 17.97; Cu, 20.38; Found: C, 37.8; H, 2.66; N, 17.9; Cu, 20.5%. (C) When an equimolecular amount of Bipy was added to the suspension of CuBipyNPM, the-oxidation of the complex was faster. After three days dark green crystals precipitated by addition of ether and were recrystallized from MeOH/ether. [Cu(Bipy)2(ONO)]NO3 calcd: C, 49.64; H, 3.33; N, 17.37; Cu, 13.13; Found: C, 49.7; H, 3.27; N, 17.1; Cu, 12.7%. Their IR spectrum corresponds to that of an authentic sample[21]. Both (B) and (C), treated in methanol solution with the equimolecular amount of NaCIO4 gave the same product, as green needles (MeOH/H20)'Cu(Bipy)z(NO)dCIO4)HzO calcd: C, 44.53: H, 3.36; N. 12.99; Cu, 11.78; Found: C, 44.6; H, 2.95; N, 12.8; Cu, 11.7% Oxidation of [Cu(Phen)2]NPM. (D) Molecular oxygen was bubbled into the dark orange methanol solution (30 ml) of the complex (0.95 g). The slow uptake of the gas (36 hr) caused the gradual variation of the colour to deep green-brown, while a pea-green powder precipitated. In the presence of an equimolecular amount of NPMH the oxidation rate was faster, so that the gas uptake was complete within 3 hr and a clear pale green solution was obtained. In both cases the products precipitated by ether showed analytical and spectroscopic variations from run to run and seem to be mixtures of [Cu(Phen)dONO)]NO: and [Cu(Phen)dONO)]NO3. Formation of solid solutions cannot be excluded. In general recrystallized products have analyses which correspond to 1:1 ratio of the above compounds, as for example Cu(Phen)2(NO~)~. Cu(Phen)~ (NO~)NO3. 2MeOH calcd: C, 54.00; H, 3.63; N, 15.12; Cu, 11.43; MeOH, 5.76; Found: C. 54.5: H, 3.54; N, 15.1; Cu, 11.4; MeOH,

:

1

5.5%. Almost pure samples of [Cu(Phen)~(ONO)]NO~ (D) were isolated from the mother liquors of the above products, by further concentration and addition of ether. Dark green crystals separated almost immediately by addition of NaC10, in equimolecular amounts to methanol solutions o:[ the above oxidation products. Their IR spectra and analyses are in agreement with those of [Cu(Phen)~(ONO)]CIO,[26]. (E) Prolonging the contact time with oxygen to three days, large green crystals were obtained by addition of ether and standing. Their IR spectrum and analysis correspond well to those of an authentic sample of [Cu(Phen)2(ONO)]NO3.MeOH. Also in this case a methanol solution of the above complex, treated with an equimolecular amount of NaCIO4 gave [Cu(Phen)~(ONO)]CIO4. (F) The mother liquors of the above preparations were evaporated to dryness and dissolved in hot water. The blue powder, which precipitated on cooling, was filtered off, washed with acetone and dried over drierite. Its analysis and IR spectrum are in agreement with those of an authentic sample of [CuPhen(OH)]2(NO)~)~.2H20. Synthesis of authentic samples [CuBipy(OH)]dNO2)2.4H20. An aqueous solution (10 ml) of Ba(NO2)~.H~O (0.60g, 2.42 mmole) was added to a hot solution (40 ml) of [CuBipy(OH)]2SO4.5H20 (1.5 g, 2.27 mmole) [24a] in the same solvent and the mixture was heated to favour the formation of BaSO4. The solid was filtered off and the solution allowed to evaporate slowly. After some days the large dark blue crystals formed were washed with water and dried in vacuo m.p. 23,1/8°C (expl.) C2oH2~N~O,oCu2 calcd: C, 37.68; H, 4.11; N, 13.18; Cu, 19.93; Found: C, 37.1; H, 3.61: N, 13.1; Cu, 20.12%. [CuPhen(OH)]dNOO2.2H~O. An aqueous solution t10 ml) of Ba(NO2)2.H20 (0.19g, 0.76 mmole) was added to a stirred hot aqueous solution (20ml) of [CuPhen(OH)]2SO4.SH_~O 10.50g, 0.71 mmole)[24a]. The BaSO4 was filtered off and the blue solution separated a microcrystalline powder of the same colour on cooling. C24H2:.N~O~Cu2 calcd: C, 44.38; H, 3.41; N. 12.94; Cu, 19.56; Found: C, 44.9; H, 3.70; N, 13.0; Cu, 19.7%. CuPhen(ONO)2. Solid Ba(NO2):.H20 (0.60 g, 2.42 mmole) was added to a stirred boiling ethanol suspension of CuPhenSO4.2H20 (0.95 g, 2.40 minnie)[29]. The solution colour turned slowly to deep green, while BaSO4 precipitated. From the clear solution silky dark green needles precipitated on cooling. They were washed with ethanol and ether and dried in vacuo m.p. 24(M°C (after gradual darkening above 190°C). Ctzsn2oNaO4 ~Cu calcd: C, 42.92; H, 2.41; N, 16.69; Cu, 18.92; Found: C~ 43.0; H, 2.39; N, 16.6; Cu, 18.9. The complex is 1:1 electrolyte in metMnol (64.1 fl ' cm 2 tool-', 25°C), but does not conduct in nitrobenzene. [Cu(Phen)dONO)]NO~.H~O. A methanol solution (25 ml) of Phen.H20 (1.0g, 5.0mmole) was added to a stirred aqueous solution (25 ml) of CuSO, • 5H20 (0.62 g, 2.5 retool), giving a deep blue colour, which turned to green by addition of solid NaNO2

280

N. MARSICH and A. CAMUS

(0.40 g, 5.7 mmole). Slow evaporation of the solution gave green needles, very soluble in methanol and acetone, which were washed with little water and dried in vacuo m.p. 278°C (after gradual darkening above 256°C). C24HlsN6OsCu calcd: C, 53.98; H, 3.40; N, 15.74; Cu, 11.90; Found: C, 54.3; H, 3.42; N, 15.8; Cu, 11.90%. The complex is 1:1 electrolyte (MeOH: 86.5; nitrobenzene: 32.9f/-~cm2mo1-1, 25°C). By recrystallization from methanol the water molecule exchanges with this solvent. [Cu(Phenh(ONO)]NO3'MeOH. (a) A methanol solution (20 ml) of Phen.H:O (0.50g, 2.52mmole) and solid NaNO2 (0.08g, 1.15 mmole) were added to a stirred aqueous solution (20ml) of Cu(NO3)2.3H20 (0.30 g, 1.24 mmole). The suspension was heated until complete solution of the nitrite. The shining green crystals separated on cooling and standing were recrystaUized from methanol m.p. 318-20°C (after gradual darkening above 260°C) C2~H2oN606Cu calcd: C, 53.24; H, 3.57; N, 14.90; Cu, 11.27; MeOH 5.68; Found: C, 53.3; H, 3.54; N, 14.7; Cu, 11.2; MeOH, 5.5%. The complex is I : 1 electrolyte (MeOH 95.3; nitrobenzene 29.2 II -~ cm 2 mol -~, 25°C). (b) An aqueous solution of KNO~ (0.020g, 019mmol) was added to a methanol solution of Cu(Phenh(NO2hH20 (0.10g, 0.19mmole). The green solution was concentrated almost to dryness and the solid filtered off and dissolved in methanol. Large green crystals of [Cu(PhenhONO]NO3-MeOH deposited overnight. Acknowledgements--We thank CNR (Rome) for financial support and Dr. E. Cebulec for elemental analyses and M.W. measurements. REFERENCES 1. N. Marsich and A. Camus, J. Organometal. Chem. 81, 87 (1974). 2. A. Camus, N. Marsich and R. Mosca, J. Inorg. Nucl. Chem. 38, 1967 (1976). 3. D. P. Graddon and N. D. Harradine, Austral. J. Chem. 24, 1788 (1971). 4. J. Zagal, E. Spodine and W. Zamudio, J. Chem. Soc. (Dalton Trans.) 85 (1974). 5. A. A. Schilt and R. C. Taylor, J. Inorg. Nucl. Chem. 9, 211 (1959). 6. A. Camus, N. Marsich, G. Nardin and L. Randaccio, J. Chem. Soc. (Dalton Trans.) 2560 (1975). 7. A. Camus, N. Marsich, G. Nardin and L. Randaccio, Inorg. Chim. Acta, L 33 (1975). 8. M. J. Brookes and N. Jonathan, J. Chem. Soc. (A),1529 ( l%8). 9. B. M. Gatehouse, J. Inorg. Nucl. Chem. 8, 79 (1958).

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