Figure 50: left: Transient UVvis difference spectra of 4 in THF at selected pump-probe delays (pump wavelength: 530 nm). The black line shows the scaled linear absorption spectrum. right: Time-dependence of the integrated absolute absorption changes (red line is a bi-exponential fit withτ1= 1.8 ps andτ2= 11.1 ps).
Figure 51: left: Transient UVvis difference spectra of 4 in THF at selected pump-probe delays (pump wavelength: 475 nm). The black line shows the scaled linear absorption spectrum. right: Time-dependence of the integrated absolute absorption changes (red line is a bi-exponential fit withτ1= 1.5 ps andτ2= 9.2 ps).
Figure 52: left: Transient UVvis difference spectra of 4 in THF at selected pump-probe delays (pump wavelength: 380 nm). The black line shows the scaled linear absorption spectrum. right: Time-dependence of the integrated absolute absorption changes (red line is a bi-exponential fit withτ1= 1.1 ps andτ2= 8.3 ps).
Figure 53: left: Transient UVvis difference spectra of 4 in THF at selected pump-probe delays (pump wavelength: 330 nm). The black line shows the scaled linear absorption spectrum. right: Time-dependence of the integrated absolute absorption changes (red line is a bi-exponential fit withτ1= 1.3 ps andτ2= 9.9 ps).
Figure 54: Transient IR difference spectra of4 in THF at selected pump-probe delays (pump wavelength: 400 nm).
W Cl
r.t. Room Temperature BDE Bond dissoziation energy BDFE Bond dissoziation free energy equiv. Equivalents
FMO Frontier Molecular Orbitals HER Hydrogen Evolution Reaction NRR Nitrogen Reduction Reaction HOMO Highest Occupied Molecule Orbital LUMO Lowest Unoccupied Molecule Orbital MO Molecular Orbital
PCET Proton Coupled Electron Transfer SOMO Single Occupied Molecule Orbital
15-cr-5 15-crown-5 (1,4,7,10,13-Pentaoxacyclopentadecane) [BArF24]– Tetrakis(3,5-bis(trifluoromethyl)phenyl)borate
[Fc] Ferrocen
HPNP bis(2-(di-tert-butylphosphanyl)ethyl)amin,HN(CH2CH2PtBu2)2
Pr iso-Propyl
LutH 2.6-lutidinum, 2.6-Me2-C5H3NH+
Np Neopentyl
[PPN]+ µ-nitrido-bis(triphenylphosphan), [(Ph3P)2N]+
tBu tert-Butyl
TrenTIPS N(CH2CH2NSiiPr3)3
NMR Nuclear Magnetic Resonance COSY Correlation Spectroscopy
HMBC Heteronuclear Multiple Bond Correlation HSQC Heteronuclear Single Quantum Coherence
s Singulett
d Duplett
t Triplett
q Quartett
qu Quintett
sex Sextett
hpt Heptett
m Multiplett
br broad
RE Reference Electrode WE Working Electrode
EPR Electron Paramagnetic Resonance HFI Hyperfine Interaction
MS Massenspectrometry ESI Electrospray Ionisation
LIFDI Liquid Field Desorption Ionisation UVvis Ultraviolett / visibile
SQUID Superconducting Quantum Interference Device TIP Temperature Independent Paramagnetism PI Paramagnetic Impurity
IC Internal Conversion ISC Inter System Crossing
IVR Intramolecular vibrational redistribution LMCT Ligand to Metal Charge Transfer
LLCT Ligand to Ligand Charge Transfer MLCT Metal to Ligand Charge Transfer MMCT Metal to Metal Charge Transfer VC Vibrational Cooling
6.1 Spectroscopic Results
6.1.1 [WCl3(PNP)] (5)
a ap sa sap fa fap ta tap [a [ap pa pap ]a ]ap Ca Cap Da Dap -a -ap s a
55
aDf
Cas]5]]
-ast
is[[
is[s istD istp
55
ist-ap
Figure 55: 1H NMR Spectrum of 5in C6D6 at r.t.
o
Parts of this work have been published in:
-"Selectivity of tungsten mediated dinitrogen splittingvs.proton reduction", B. Schluschaß, J. Abbenseth, S. Demeshko, M. Finger, A. Franke, C. Herwig, C. Würtele, I. Ivanovic-Burmazovic, C. Limberg, J. Telser, S.
Schneider,Chemical Science,2019,10, 10275-10282.
-N.A. Maciulis "Exploring redox properties of bis(tetrazinyl)pyridine (btzp) complexes of group VI metals, tetrazine and phosphine assisted reduction of H2O, and dinitrogen cleavage and functionalization"Ph.D.
Thesis, Indiana University Bloomington,2019.
-P.-M. Padonou "Reaktivität dimerer N2-verbrückter Wolfram-PNP-Pinzetten Komplexe"Bachelor Thesis, Georg-August-Universität Göttingen,2018.
-J. Schneider "Synthese und Funktionalisierung von Wolfram-PNP-Nitrid Komplexen"Bachelor Thesis, Georg-August Universität Göttingen,2019.
6.1.2 [(N2){WCl(PNP)}2](1)
tsH ts-[s[
[s]
[s8 [sH [s-ps[
ps]
ps8 psH ps-]s[
]s]
]s8 ]sH
77
[s[[[s[4[s[8[s[F[sp-[s]8[s8][s8H
[sH][sHF
pspF
ps]F
]s84]s8F7F]sTT
Figure 56: 1H NMR Spectrum of 1in THF−d8 at r.t.
tf t.
[f [.
pf p.
]f ].
.f ..
9f 9.
f . f
55
pf tpfptpt ptp[ fp[ tp 9pp p
]
Figure 57:13C{1H} NMR Spectrum of 1in THF−d8at r.t.
s]
s].[
s]][
s][[
sp[
sp[
sp.[
sp][
sp[[
s[
s[
s.[
s][
[ ][
.[
[ [ p[[
p][
p.[
p[
6 6
3pfp
Figure 58:15N{1H} NMR Spectrum of 15N-1in THF−d8 at r.t.
] fs f]
ts t]
[s []
ps p]
]s ]]
As A]
(s (]
ds d]
)s )]
fss fs]
00 0ch
)tl) cfp(l]h
0ch d(ld cfp(lph
d(lpddl[)tl])[lp
Figure 59: 31P{1H} NMR Spectrum of 1in THF−d8at r.t.
-3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 -0.016
-0.012 -0.008 -0.004 0.000 0.004 0.008 0.012 0.016
current[mA]
potential vs Fc +
/Fc [V]
100 mV/s
200 mV/s
400 mV/s
600 mV/s
800 mV/s
1000 mV/s
Figure 60: CV of 1in 0.1 M solution of [nBu4N][PF6] in THF (WE = GC, RE = Ag/Ag+, CE = Pt) at different scan rates.
800 1000 1200 1400 1600 1800 2000 2200 2400 1347
[cm -1
] 15
N
14
N
THF-d 8
1300 1350 1400 1450
1392
Figure 61: rRaman Spectrum (457 nm) of 14N/15N-1in frozen THF−d .
6.1.3 [(N2){WCl(PNP)}2]+(2)
] p p5 p7 pp pt [ [5 [7 [p [t 5
7 p t p 7 5
00
p9s7
p.st5
ppst5
[7s[7
.s5t
ps]ps.[ps]s[]7s]9
Figure 62: 1H NMR Spectrum of 2-[BPh4] in THF−d8at r.t.
800 1000 1200 1400 1600 1800 2000 2200 2400
[cm -1
] 14
N
15
N
THF-d 8
1350 1400 1450
1360
1414
Figure 63: rRaman Spectrum (457 nm) of 14N/15N-2-[BPh4] in frozen THF−d8.
1.88 1.90 1.92 1.94 1.96 1.98
g 14
N
15
N
sim
g = 1.93
A(
183
W )= 220 MHz
A ( 31
P) = 56 MHz
Figure 64: Comparison of the EPR-Spectra of 14N/15N-2, both in THF at r.t.
0 50 100 150 200 250 300
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40
exp
sim
M
Tcm
3 mol
-1 K
T [K]
Figure 65: χMT vs. T plot for 2-[BArF24]. The open circles are the observed suscepti-bility, the red solid line corresponds to the best fit with the parameters g = 1.82 and TIP =120·10−6 cm3mol−1(TIP: temperature independent paramagnetism).
6.1.4 [(N2){WCl(PNP)}2]2+ (3)
97 9t 77 7t .7 .t ]7 ]t p7 pt [7 [t 7 t 7
55
9pst[
79s78
.9st
]pst8
ss[ 8st]
[s79[s8]]s.]s7]s8.s[.s]p
Figure 66: 1H NMR Spectrum of 3-[Al(OC(CF3)3)4]2 in THF−d8at r.t.
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
1356
cm -1 14
N
15
N
THF-d 8
1400
1300 1350 1400 1450
Figure 67: rRaman Spectrum (514.5 nm) of 14N/15N-3-[Al(OC(CF3)3)4]2 in THF−d8 at -100◦C.
0 50 100 150 200 250 300 0.0
0.1 0.2 0.3 0.4 0.5 0.6
J = -59 cm -1 exp
sim
PI (0.6 %)
M
Tcm
3 mol
-1 K
T [K]
Figure 68: χMT vs. T plot for 2-[Al(OC(CF3)3)4]2. The open circles are the ob-served susceptibility, the red solid line corresponds to the best fit with the param-eters g = 1.90, J = –59 cm−1, TIP =230·10−6 cm3mol−1and PI = 0.6% (S= 1, the blue broken line, PI: paramagnetic impurity).
6.1.5 [W(N)Cl(HPNP)]+ (11)
1.88 1.89 1.90 1.91 1.92 1.93 1.94 1.95 1.96 1.97 1.98 1.99
g mes
sim
g = 1.93
A(
183
W )= 220 MHz
A ( 31
P) = 56 MHz
Figure 69: EPR-Spectrum of 11in THF at r.t.
4000 3500 3000 2500 2000 1500 1000 500
3079
[cm -1
] 14
N
15
N 1058
1080 10601040 10201000
Figure 70: ATR-IR-Spectrum14N/15N-11.
6.1.6 in situ[(HPNP)ClW-(N2)-WCl(PNP)]+ (12)
flN
fl
6.1.7 in situ[{(HPNP)ClW}(μ−N2)]2+ (13)
aHs aT]
aTs a.]
a.s a]]
a]s ap]
aps a[]
a[s at]
ats af]
afs a]
s ] fs f]
ts t]
[s []
ps p]
]s
00
aTplH[
a[slHt
atpl]p
aHlTs
flTp[l]H0aH
f.lF.
tTlf.
p]lt.
Figure 77:1H NMR Spectrum of 13-(OTf)2 in THF−d8 at -65◦C.
6.1.8 [(N2){WCl(CO)(PNP)}2]( 8)
tst tsp ts9 ts ts [st [sp [s9 [s [s pst psp ps9 ps ps ]st ]sp ]s9 ]s ]s 9st 9sp
22
[sp[s][[s]][s9[[s9][s95[s5[[s5][s55[s5[st[sp[s
ps9p
]sp
]s55
Figure 78: 1H NMR Spectrum of 8in C6D6 at r.t.
]t [t [t ]t 4t Ct Dt [[t []t [4t [Ct [Dt p[t p]t p4t pCt pDt
00
p4s.p4sC][st][s[][s]][s.]Csp]Cs6]6s]]6s64Dsp4Ds.
[p6s[088
p8]s[
Figure 79: 13C{1H} NMR Spectrum of 8in C6D6 at r.t.
s99 s9[
s69 s6[
s.9 s.[
s]9 s][
sp9 sp[
s9 [ 9 p[
p9 ][
]9 .[
.9 6[
69 9[
99
0 0
s[f
Figure 80: 15N{1H} NMR Spectrum of 8in C6D6 at r.t.
s][
sp[
sp[
sp.[
sp][
sp[[
s[
s[
s.[
s][
[ ][
.[
[ [ p[[
p][
p.[
p[
p[
][[
0 0
9f[
Figure 81:31P{1H} NMR Spectrum of 8in C6D6 at r.t.
fl]
fl7 flP tlf tl[
tl]
tl7 tlP [lf [l[
[l]
[l7 [lP plf pl[
pl]
pl7 plP ]lf
t 444
75l9]
75l97 75l9P 75lPf 75lP[
75lP]
75lP7 75lPP 75l{f 75l{[
75l{]
75l{7 75l{P 77lff 77lf[
77lf]
pt44
tl7fi75l{f tl]pi75l{f tlpti75l{f tl5[i75l{f
Figure 82: 1H-31P-HMBC NMR Spectrum of 8 in C6D6 at r.t. showing a cross-peak for all fourtBu-groups to only one31P-signal.
800 1000 1200 1400 1600 1800 2000 2200 2400
1394
[cm -1
] 14
N
15
N
THF-d 8
1300 1350 1400 1450 1500 1437
Figure 83: rRaman Spectrum (457 nm) of 14N/15N-8in frozen THF−d8.
4000 3500 3000 2500 2000 1500 1000 500 1883
1887
1867
1867
[cm -1
] 1883
1867 1925 1900 1875 1850
15
N
14
N
Figure 84: ATR-IR Spectrum of 8.
-2.8 -2.6 -2.4 -2.2 -2.0 -1.8 -1.6 -1.4 -0.020
-0.018 -0.016 -0.014 -0.012 -0.010 -0.008 -0.006 -0.004 -0.002 0.000 0.002 0.004 0.006 0.008
100 mV/s
200 mV/s
400 mV/s
600 mV/s
800 mV/s
1000 mV/s
current[mA]
potential vs Fc +
/Fc [V]
-2.2 -2.0 -1.8 -1.6
Figure 85: CV of 8 in 0.1 M solution of [nBu4N][PF6] in THF (WE = GC, RE = Ag/Ag+, CE = Pt) at different scan rates.
6.1.9 [(N2){W(CO)(PNP)}2](4)
spD sp7 sp3 sp]
sp[
sD s7 s3 s]
[ ] 3 7 D p[
p]
p3 p7
8 8
sp7f[]
sp3f.7
s]f5D
.f5.
3f537f.D7f35Cfp7877Cf]5CfC9
p]fD5p.f7]p3f7[
1H NMR Spectrum of 4 in C6D6at r.t.
800 1000 1200 1400 1600 1800 2000 2200 2400
[cm -1
] 14
N
15
N
THF-d 8
1589
1540
1475 1500 1525 1550 1575 1600 1625 1650
4000 3600 3200 2800 2400 2000 1600 1200 800 400 (Nitride)
1883
1785
1745 1741
1785
[cm -1
] 1785
1741 1850 1800 1750 1700 1650
14
N
15
N
Figure 87: ATR-IR Spectrum 4.
0 50 100 150 200 250 300
0.0 0.1 0.2 0.3 0.4 0.5 0.6
sim
exp
PI (8.3 %)
M
Tcm
3 mol
-1 K
T [K]
D = 406.6 cm -1
Figure 88: χMT vs. T plot for 4. The open circles are the observed susceptibil-ity, the red solid line corresponds to the best fit with the parameters g = 1.74 and D = 406.6 cm−1(TIP: temperature independent paramagnetism).
6.1.10 [W(N)(CO)(PNP)] (16)
lf [ f f f [ f ] f 5 f t f t [ t ] t 5 t [ f [ [ [ ] [ 5 [ p f p [ p ] p 5 p ] f ] [
..
fffft
t ]t 9ft 9tt 95t 7
p 75
p
Figure 89:1H NMR Spectrum of 16in C6D6 at r.t.
] [t [t ]t .t 8t t [[t []t [.t [8t [t p[t p]t p.t p8t pt ][t ]t
00
p4s.ps[ps]].st].s[
66sp
p]s4
Figure 90: 13C{1H} NMR Spectrum of 16in C6D6at r.t.
[.s [s [s [s pss pfs pts p[s pps p]s p.s ps ps ps ]ss ]fs ]ts ][s
00
ppls
Figure 91: 15N{1H} NMR Spectrum of 16in C6D6at r.t.
ip p s sp f fp t tp [ [p p pp ] ]p . .p p p s s p ss ssp sf
00
s[a[
Figure 92: 31P{1H} NMR Spectrum of16in C6D6 at r.t.
4000 3500 3000 2500 2000 1500 1000 500 1885
1883
[cm -1
] 14
N
15
N
1883 998
973
10201000 980 960 1925190018751850
Figure 93: ATR-IR Spectrum of16.
6.1.11 [W(N)(CO)(HPNP)]+(20)
sls sl]
fls fl]
tls tl]
[ls [l]
pls pl]
]ls ]l]
9ls 9l]
Cls Cl]
Dls
55
slC]slCDslDsflfpflf9flfDfl9p
tltD
tl][
[lpls]
]l[
Clf9599
Figure 94: 1H NMR Spectrum of 20in C6D6at r.t.
.t pt t pt .t Ct 7t [tt [pt [.t [Ct [7t ptt ppt p.t pCt p7t ]tt ]pt ].t
00
p]stp7stp7s.].sC]5s5
57s5
[p7s[0CC
pD7s7
Figure 95: 13C{1H} NMR Spectrum of 20in C6D6 at r.t.
[s [s [s pss pfs pts p[s pps p]s p.s ps ps ps ]ss ]fs ]ts
00
pp]lf
Figure 96:15N{1H} NMR Spectrum of 20in C6D6 at r.t.
s][
sp[
sp[
sp3[
sp][
sp[[
s[
s[
s3[
s][
[ ][
3[
[ [ p[[
p][
p3[
p[
p[
][[
0 0
9fp3
Figure 97:31P{1H} NMR Spectrum of 20in C6D6 at r.t.
4000 3500 3000 2500 2000 1500 1000 500
[cm -1
] 14
N
15
N
3118
1928 1048
1014
1075105010251000
Figure 98: ATR-IR Spectrum of 20.
6.1.12 [W(CO)3(HPNP)] (9)
f 6 f f t t t p t 6 t t [ t [ p [ 6 [ [ p t p p p 6 p p ] t ] p
55
t ppt p]t p8t pt pt 66
[ ][
[ 6p
p ]p 6]
Figure 99:1H NMR Spectrum of 9in CD2Cl2 at r.t.
is s f t [ p ] . C D s ss sf st s[
sp s]
s.
sC sD f fs ff ft f[
00
fpa[ta[ta]t.attCa.
p[a 0ffpCa
ff[afff]a[
Figure 100: 13C{1H} NMR Spectrum of 9in CD2Cl2at r.t.
ip p s sp f fp t tp [ [p p pp ] ]p . .p p p s s p
00
ap
Figure 101:31P{1H} NMR Spectrum of 9in CD2Cl2 at r.t.
4000 3500 3000 2500 2000 1500 1000 500
[cm -1
] 1896
1773
1753 3227
Figure 102: ATR-IR Spectrum of 9.
6.1.13 [WI(CO)2(PNP)] (18)
asl sls sl]
fls fl]
tls tl]
[ls [l]
pls pl]
]ls ]l]
9ls 9l]
Cls Cl]
..
flffflf[flf]fl[Cfl[flpf
flptls9tlp]tlCC
Clf9.99
Figure 103: 1H NMR Spectrum of 18in C6D6at r.t.
p .p 3p Cp 5p ]pp ].p ]3p ]Cp ]5p .pp ..p .3p .Cp
44
.CtD7pt37]t575tD7t.
CDt.
].5t]4CC
.3Dt9.97t3
Figure 104: 13C{1H} NMR Spectrum of 18in C6D6 at r.t.