Synthesis of poorly crystallized platinum metal dichalcogenides

High-Performance Hybrid Electronic Devices from Layered PtSe2 Films Grown at Low Temperature. ACS Nano. Yim, Lee, McEvoy, O'Brien, Riazimehr, Berner, ...
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Znorg. Chem. 1981, 20, 501-503 Scheme 1. Proposed Intramolecular Isomerization of Coordinated Allylbenzene

IrH

501

Grant to the Department of Chemistry, University of California at Berkeley, for purchase of a 180-MHz NMR spectrometer. In addition, we thank Professor J. R. Shapley for helpful discussions. Registry NO. 1, 75751-41-6; 3, 75751-42-7; 6, 75751-43-8; 7, 75751-45-0; 8, 75751-47-2; 11, 75800-61-2; 12, 75751-49-4; [Ir(t16-C6HsC6H5)(q4-COD)+] (BF4-), 7575 1-5 1-8; [Ir(q4-COD)(CHICN)2+](BF,-), 32679-03-1; [Ir(q6-C6H6)(q4-CoD)+](OS02CF,-), 75751-52-9; [Ir(q6-l,4-C6H4(CH3)2)(q4-CoD)+](OS02CF3-), 7575 1-53-0; [Ir(q6-1,4-Cd-I4(CH3),)(q4-COD)+] (PF6-), 7575 1-54- 1; [Ir(q6-1,4-C6H4(CH,)2)(q4-CoD)+](B&112~-)1/2, 75751-55-2; [Ir(q6-C6H6)(q4-CoD)+](BF4-), 74238-34-9; [Ir(q61,3-C6H4(CH3)2)(q4-CoD)+](BF4-), 74238-40-7; [Ir(q6-1,2,3c6Hj(cH,),)(q4-c0D)+] (BF4-), 7575 1-57-4; [Ir(q6-l,2,4-C6H3(CH3)3)(q4-COD)+](BF4-), 75751-59-6; [Ir(V6-1,3,5-C6H3(CH3)3)(q4-COD)+](BF4-), 74238-44-1; [Ir(q6-1,2,3,4-C6H2(CH,)4)(q4-COD)+](BF4-), 74238-46-3; [Ir(q6-1,2,3,5-C6H2(CH3)4)(q4-COD)+](BF4-), 74238-48-5; [Ir(q6-1,2,4,5-C6H2(CH,)4)(q4-COD)+](BF4-), 74238-48-5; [Ir(q6-1,2-C6H4(CH,)2)(q4-COD)+](BF4-), 74238-38-3; [Ir(q6-cis-C6HSCH= CHCH,)(q4-COD)+](BF4-), 75751-24-5; [Ir(q6-C6HsOH)(q4(BF4-), COD)’] ( BF4-), 7575 1-26-7; [Ir(q6-tetralin)(q4-COD)+] 75751-28-9; [Ir(q6-naphthalene)(q4-COD)+](BF4-),75751-30-3; [Ir(f-9,10-dihydroanthracene)(q4-COD)+](BF4-), 75751-32-5; [Ir(q6-indene)(q4-C0D)+](BF,-), 75751-34-7; [h(q6-C6(CH,)6)(q4COD)+](BF4-), 74238-50-9; [Ir(q6-C6HsCH3)(q4-coD)+](BF4-), 74238-36-1; [Ir( q6-1,4-C6H4(CH3)2) (q4-COD)+](BFL), 74238-42-9; [Ir(q4-COD)HCl2I2,12148-12-8; [ Ir(q4-COD)(p-OCH3)I2,3308783-1; [Ir(q4-COD)C1I2,12112-67-3; Ir(q4-COD)(acac), 12154-84-6; [Ir (q6-C6D6)(q4-COD)+](BF4-), 7575 1-36-9; [Ir( q6- 1 ,4-C6D4(CD3)2)(q4-COD)+] (BF4-), 7575 1-38- 1; [Ir(q4-COD)(S( C ~ H S ) ~ ) ~ + ] ( B F75751-40-5; ~-), C&, 71-43-2; 1,2-C&(CH3)2, 95-47-6; I93-C6H4(CH,)2, 108-38-3; 1,2,3-C6H,(CH3)3, 526-73-8; 1,2,4-C6H3(CH,),, 95-63-6; 1,3,5-C6H,(CH3)3, 108-67-8; 1,2,3,4C6H2(CH3)4, 488-23-3; 1,2,3,5-C6H2(CH3)4, 527-53-7; 1,2,4,5CsH2(CH3)4, 95-93-2; C ~ H S O H 108-95-2; , C ~ H S C ~ H92-52-4; S, C ~ H S C H Z C H = C H300-57-2; ~, C~S-C~HSCH=CHCH~, 766-90-5; trans-C6HsCH 50°), corrected relative to an internal MgO standard. Thermogravimetric Analysis. The sulfur to metal ratio in the amorphous materials was determined by thermogravimetric analysis (TGA) with use of a Cahn electrobalance (Model RG) with a 0.001-mg accuracy. Approximately 30 mg of fmely powdered samples of each of the poorly crystallized products was placed in a silica bucket for heating. The maximum temperature reached was 900 OC, and the rate of heating was 30 OC/h. The sample was kept at 900 OC for 12 h after which time the furnace was shut off, allowing the sample to cool to room temperature. Magnetic Measurements. Magnetic susceptibility data were obtained with a Faraday balance equipped with a Cahn R G electrobalance, described elsewhere,” over a temperature range of 8&300 K for poorly crystallized and crystalline RuS2, OS2,ptS2,and P a 2 . Measurements were performed at field strengths between 6.25 and 10.30 kOe. The balance was calibrated by using platinum wire (xe = 0.991 X 10-6 emu/g at 275 K). No corrections were made for core (1 1) Synthesis outlined in: Brauer, G. “Handbook of Preparative Inorganic Chemistry”; Academic Press: New York, 1963; Vol. 11, p 1584. (12) Synthesis outlined in: Brauer, G. “Handbook of Preparative Inorganic Chemistry”; Academic Press: New York, 1963; Vol. 11, p 1569. (13) Morris, B.; Wold, A. Rev. Sci. Inrrrum. 1968, 39, 1937.

Inorganic Chemistry, Vol. 20, No. 2, 1981 503

Poorly Crystallized Platinum Metal Dichalcogenides

RuS,

Table 111. Thermogravimetric Analysis Results theor starting final Wt Wt mole material wt, mg wt, mg loss, mg loss, mg ratio M:S 17.19 19.05 12.99 15.15

RuS, OsS,

PdS,

PtS,

10.14 14.13 8.27 10.60

7.05 4.92 4.72 4.55

Table IV. Crystallization Parameters temp of onset of crystalliobsd material zation, "C phase

6.67 4.80 4.88 3.75

OsS,

"

"

"

'

*

Poor:y

0

C-y.t.l!

I

" +

t L

4 4

1:2.19 1:2.07 1:1.89 1:2.43

Cry.t*!!>".

L

I-.

2 -

cell parameters, A fnt a fnt b

a = 5.61014 cubic pyrite a = 5.610 (2) cubic pyrite a=5.620 (2) a = 5.6196" a = 3.543, hexagonal a = 3.544 (2), PtS, CdI, c = 5.039 (2) c = 5.038" PdS, 450 orthorhombic a = 5.457 (2), a = 5.460, b = 5.542 (2), b = 5.541, distorted c = 7.534 (2) c = 7.531'' pyrite a Cell parameters calculated from this work. Cell parameters obtained for well-crystallized materials prepared by conventional methods (Le., direct combination of the elements). RuS,

E l ' ' " ' ' " ' " ' '

-4

L

i

350 400 425

Figure 2. Powder X-ray diffraction pattern of "amorphous" and crystalline RuS2. 100

I

1

diamagnetism because of the large uncertainty in the magnitude of the corrections relative to the susceptibility of the material studied.

Results and Discussions Thermogravimetric Analysis. Thermogravimetric analysis was carried out on the reaction products after extraction with methanol and carbon disulfide in order to obtain a value for the ratio of sulfur to metal. Results of the thermogravimetric analysis are summarized in Table 111. In all cases, when the "amorphous" materials were subjected to the indicated conditions of thermogravimetric analysis, they decomposed to the metal and sulfur. X-ray powder diffraction patterns of the decomposed products confirmed the formation of metal. X-ray Analysis. Powder X-ray diffraction analysis of the reaction products showed them to be poorly crystallized. The series of annealing experiments indicated that the poorly "amorphous" platinum metal dichalcogenides showed evidence of crystallization at the temperatures indicated in Table IV. The crystallized phases observed are also summarized in Table IV. The changes in the crystalline character of RuSz as a function of annealing temperature can be seen in Figure 2. It can be seen that the Bragg peaks expected for the crystalline phase of RuS2 develop from the corresponding X-ray powder diffraction envelope of the poorly crystallized disulfide. It should be noted that the vertical-line diffraction patterns shown in Figure 2 are a schematic representation of the X-ray powder diffraction patterns observed for the crystalline phase. There was no evidence for the existence of either metal or metal oxide in any of the X-ray patterns. Similar results were obtained for OsS,, PdS,, and PtS2. Cell parameters were calculated for the well-crystallized materials and are summarized in Table IV. From Table IV, it can be seen that the calculated cell parameters are consistent with the parameters reported previously for the dichalcogenides This work. (IS) Sutarno; h o p , 0.;Reid, K. I. G. Can. J . Chem., 1967, 45, 1391. (16) Munson, R. A.; Kasper, J. S. Inorg. Chem. 1969, 8, 1198. (17) Gronvoid, F.; Haraldson, H.; Kjekshus, A. Acta Chem. Scand. 1960, (14)

14, 1879.

! 80

1

,

/

75

70

65

/

/ 60

I

I

55

50 28

ms2

3. Magnetic susceptibility ( x vs. temperature) of "amorphous" and crystalline RuS2.

F i i

prepared by conventional methods (Le., direct combination of the elements). Magnetic Measurements. RuS2 and O S 2contain low-spin d6 Ru and Os, respectively, and are known to be diamagnetic. PdS2 and PtS2contain low-spin ds Pd and Pt, respectively, and are also known to be diamagnetic. Hence, magnetic susceptibility measurements on the four "amorphous" platinum metal dichalcogenides were an important means of confirming their composition. Magnetic susceptibility was also remeasured for the same material after annealing at the temperatures stated in Table 11. At these temperatures the crystalline phases could be substantiated by X-ray analysis. Results of the magnetic susceptibility measurements are given in Figure 3. It can be seen that diamagnetic behavior is observed, as predicted for both the poorly crystallized and crystalline phases of RuS2. Similar behavior was observed for Os& PtS2, and PdS2. Acknowledgment. The authors would like to thank Exxon Research and Engineering Co., Linden, New Jersey, for the support of J.D.P. Acknowledgment is also made to Dr. R. R. Chianelli, Exxon Research and Engineering Co., Linden, New Jersey, for his helpful discussions and assistance in the prep aration of this manuscript. In addition, acknowledgment is made to the National Science Foundation, Washington, D.C. (Grant No. DMR-79-23605), for the support of R.B.K. Finally, the Materials Research Laboratory Program at Brown University is also acknowledged. Registry NO. R u S ~ , 12166-20-0; OSS~,12137-61-0; PdS2, 12038-21-0; ( N H ~ ) ~ R u C & 18746-63-9; , (NHJ212137-75-6; -2, OSCI~,12125-08-5; (NH4)2PdC&, 19 168-23-1; (NHd),PtCI,, 16919-58-7; H2S, 7783-06-4.