MSMS MMass SSpectrometry

OrganometallicsOrganometallics

Centro de espectrometría de masa (Harvard)

General Information The word that best describes the mass spectrometry of inorganic and

Organometallic molecules is "difficult". Many species are intractable to mass spectrometry for one of a number of

reasons.     To see our recommendations for Organometallic, click here.

Recommendations We recommend you confer with your friendly local mass

spectrometrist before preparing any organometallic or inorganic samples for mass spectrometry.

Métodos de Ionización (los más usuales)

• EI (Impacto Electrónico): se volatiliza la muestra y se ioniza con un haz de electrones. M+. y fragmentos

• FAB (Fast Atom Bombardment): se coloca la muestra en una matriz líquida (un alcohol) y se impacta con un haz de átomos de Xe. (M+H)+; (M+Na)+, (M+matriz)+, fragmentos, etc

• MALDI (Matrix-Assisted Laser Desorption/Ionization): se coloca la muestra en una matriz sobre un metal y se impacta con un laser. Muy usado para péptidos y proteínas.

• ESI (ElectroSpray Ionization): se disuelve la muestra, se pasa por un capilar a 5 kV, que la dispersa en microgotas. [M+nH]n+, [M+Na]+, etc.

Isotope patternsIsotope patterns

Aluminium Bromide:Aluminium Bromide:AlBrAlBr++ 2727Al : 100% Al : 100%

7979Br : 51% Br : 51% 8181Br : 49%Br : 49%

Isotope Isotope patternspatterns

6363Cu: 69.1%Cu: 69.1%6565Cu: 30.9%Cu: 30.9%

3535Cl: 75.5%Cl: 75.5%3737Cl: 24.5%Cl: 24.5%

6363CuCu3535ClCl6363CuCu3737ClCl6565CuCu3535ClCl

6565CuCu3737ClCl

Abundance of first isotope peak Abundance of first isotope peak MM: .691.691 x .755.755 = .521.521

For next isotope peakFor next isotope peak: M+2: M+2: .691.691 x .245.245 = .169.169

.309.309 x .755.755 = .233.233} .403.403

For next isotope peakFor next isotope peak: M+4: M+4: .309.309 x .245.245 = .076.076

Poly-isotopic metalsPoly-isotopic metals

Metal isotope pattern are distorted by Metal isotope pattern are distorted by 1313C and C and 22H H

Poly-isotopic metalsPoly-isotopic metals

When more than one metal is present: pattern is affected in a When more than one metal is present: pattern is affected in a predictable waypredictable way

Ru1Ru1

Ru2Ru2

(bpy)(tpy)RuN2ArN2Ru(bpy)(tpy)?

Reacciones ion-moléculaReacciones ion-molécula

Se producen ocasionalmente, dando lugar a iones de MAYOR masa que el ion molecular.

Cr(CO)Cr(CO)66++ + Cr(CO)6 --> Cr(CO)Cr(CO)1010

+ + 2 CO

FragmentationFragmentation1.1. The charge is likely to remain on Metal-containing fragmentThe charge is likely to remain on Metal-containing fragment

MMLLnn

M M LLn-1n-1++ + LL

LL++ + MM LLn-1n-1 Less likely

2.2. Rearrangement involving hydrogen migration are frequentRearrangement involving hydrogen migration are frequent (M => Si, Ge, Sn, Pb…) (M => Si, Ge, Sn, Pb…)

R

R

M

H R

R

M H CH2 CH2

R

R

M O

H

CH3

R

R

M H MeHC O

FragmentationFragmentation

3.3. Migration of Halogens is very commonMigration of Halogens is very common

M (CM (C66FF55))33++ (C(C66FF55))2 2 Sn FSn F

++ + C6F4

M => Si, Ge, Sn, PbM => Si, Ge, Sn, Pb

4.4. Migration of Alkyl to metal is also commonMigration of Alkyl to metal is also common

Fe

R

O

Fe

R

Fe+

R

Transfer of Transfer of RR is influence by is influence by electronegativityelectronegativity of the of the R groupR group

Rearrangement process process

““McLafferty” type of rearrangement involving metal instead of HMcLafferty” type of rearrangement involving metal instead of H

OMR3

+

CH2

CH2

CH2R

OMR3

+

CH2R

CH2

CH2

+

This rearrangement depends on readiness of metal to This rearrangement depends on readiness of metal to become pentacoordinate (using it’s d-orbitals)become pentacoordinate (using it’s d-orbitals)

Metal Carbonyls (Co)

Metal Carbonyls (Fe)

Metal Carbonyls (Fe)

Carbonyl halide compounds

TerminalTerminal

BridgingBridging

Carbonyl halide compounds

TerminalTerminal

BridgingBridging

Loss of Loss of COCO and and XX occur with occur with equal easeequal ease

Loss of Loss of COCO occur occur stepwise with stepwise with retention of retention of MM22XX22

than further than further XX loss can occurloss can occur

Cs2IrCl5CO (ESI-MS(-))

195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 285 290 295 300 305 310 315 320 325 330 335 340 345 350 355 360 365 370m/z0

100

%

amostra2 4 (0.081) Sb (5,40.00 ); Cm (3:53) TOF MS ES- 1.34e4360.8394

358.8326332.8458

197.9033 330.8330

199.9091

212.1047 230.1206 248.1298

336.8465

362.8295

364.8250

366.8259

IrCl4CO-

IrCl5CO2-

IrCl4-

MSMS 199 (IrCl5CO2-)

195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275 280 285 290 295 300 305 310 315 320 325 330 335 340 345 350 355 360 365 370m/z0

100

%

amostra2msms197 39 (0.782) Sb (5,40.00 ); Cm (36:82) TOF MSMS 198.90ES- 109198.9132

362.8519

360.8618

334.8647

332.8458 362.9862

IrCl4-

IrCl4CO-

FTMS

• Fourier transform mass spectrometry, is a type of mass spectrometer for determining the m/z of ions based on the cyclotron frequency of the ions in a fixed magnetic field.

• The ions are trapped in a magnetic field with electric trapping plates where they are excited to a larger cyclotron radius by an oscillating electric field perpendicular to the magnetic field. The excitation also results in the ions moving in phase (in a packet). The signal is detected as an image current on a pair of plates which the packet of ions passes close to as they cyclotron. The resulting signal is called a free induction decay (FID), transient or interferogram that consists of a superposition of sine waves. The useful signal is extracted from this data by performing a Fourier transform to give a mass spectrum.

complexo 3b tol terBUO com alcool #1 RT: 0,01 AV: 1 NL: 3,80E5T: FTMS + p ESI Full ms [100,00-2000,00]

1178 1180 1182 1184 1186 1188 1190 1192 1194 1196m/z

0

20

40

60

80

100

120

140

160

180

200

Rel

ativ

e A

bund

ance

1189,1192 1191,1189

1187,1194 1192,1201

1197,19681186,1198 1193,1190

1185,1198 1196,1968

1184,1209

1182,12141179,4693

[Ru(CpPh[Ru(CpPh55)])]22BrO+BrO+

Ru Ru

Br

O

complexo 3b tol terBUO 20 min #1 RT: 0,01 AV: 1 NL: 3,43E4T: FTMS + p ESI Full ms [370,00-2000,00]

1250 1252 1254 1256 1258 1260 1262m/z

0

10

20

30

40

50

60

70

80

90

100

110

120

Rel

ativ

e A

bund

ance

1257,11

1258,111256,111259,11

1255,11 1260,111254,11 1261,11

1253,11

1262,111251,18

1251,71

C79H57O3Ru2: C79 H57 O3 Ru2 pa Chrg 1

1245 1250 1255 1260 1265 1270m/z

0

10

20

30

40

50

60

70

80

90

100

Rel

ativ

e A

bund

ance

1259,24

1256,24

1260,241257,24

1254,24

1253,24 1261,25

1251,241262,24

1250,241248,24 1263,25

1264,251245,251266,26 1268,26

[(CpPh[(CpPh55)Ru(CO))Ru(CO)22]]22(PhCH(PhCH22O)O)++