Bimetallic nitrido complexes are of interest because it was found that nitrido‐bridged
diiron(IV) complexes are active catalysts for alkane oxidation. In this thesis, we report the
synthesis of heterobimetallic nitrido complexes by reactions of cyclopentadienyl and
porphyrin complexes with ruthenium(VI) terminal nitrido complexes.
[CpRu{(μ‐N)Ru(L
OEt)Cl
2}{(μ‐Cl)RuCl(L
OEt)(μ
2,μ’‐N=C
5H
4=NH)Ru(L
OEt)Cl
2}] (Cp =
cyclopentadienyl; L
OEt- = [CoCp{P(O)(OEt)
2}]
‐) consisting of a symmetrical Ru
IV=N=Ru
IV bridge
has been synthesized from reaction of [Cp
2Ru] with [L
OEtRu(N)Cl
2]. The Cp*Ru(IV) μ‐nitrido
complexes [{Cp*Ru(μ‐N)M(L
OEt)}
2(μ‐Cl)
4][PF
6]
2 (M = Ru and Os), [{Cp*Ru(μ‐N)Ru(AsPh
3)Cl}
2(μ‐Cl)
4(μ‐O
2PF
2)][PF
6] and [{Cp*Ru(μ‐N)Ru(SC
6F
4H)
2}
2(μ‐SC
6F
4H)
4] were synthesized by treatment of [Cp*Ru(MeCN)
3]PF
6 with [L
OEtM(N)Cl
2] (M = Ru and Os), [Ru(N)(AsPh
3)
2Cl
3] and anionic [
nBu
4N][Ru(N){SC
6F
4H}
4] respectively. X‐ray diffraction studies indicated that the nitride bridges in these tetranuclear cyclopentadienyl complexes are linear and symmetrical, consistent with the (Cp*)Ru
IV=N=Ru
IV formulation. Metathesis of [Cp*Ru(MeCN)
3]PF
6 with [
nBu
4N][Ru(N){OCH(CF
3)
2}
4] gave [Cp*Ru(MeCN)
2(μ‐N)Ru{OCH(CF
3)
2}
4] containing an unsymmetrical Ru
VI≡N-Ru
II unit.
Heterometallic nitrido‐bridged porphyrin complexes [(H
2O)(por)M(μ‐N)RuCl
2(L
OEt)] (M = Ru, Os, Fe; por = 5,10,15,20‐tetra(p‐tolyl)porphyrin (TTP
2-) or 5,10,15,20‐tetra(phenyl)porphyrin (TTP
2-)dianion) featuring symmetric nitrido bridges were prepared from reactions of [L
OEtM(N)Cl
2] (M = Ru and Os) with group 8 metalloporphyrins. The aqua ligands in these complexes can be substituted by unidentate
or bidentate N‐donor ligands to give [(py)(TTP)Ru(μ‐N)RuCl
2(L
OEt)] (py = pyridine), [(pyz)(TTP)Ru(μ‐N)RuCl
2(L
OEt)] (pyz = pyrazine), or tetranuclear [Fe(TPP)(μ‐N)RuCl
2(L
OEt)]
2(μ‐4,4’‐bpy) (4,4’‐bpy = 4,4’‐bipyridyl). [(Et
2O)(TPP)Fe(μ‐N)Ru(py)
2Cl
3] obtained from reaction of Fe(TPP)py
2 with [Ru(N)(AsPh
3)
2Cl
3] also consists of a symmetrical nitrido bridge, consistent with a Ru
IV=N=Fe
IV formulation. In contrast with the group 8 counterparts, the group 9 μ‐nitrido complexes [(TPP)ClRh(μ‐N)RuCl
2(L
OEt)] and [(TPP)Co(μ‐N)RuCl
2(L
OEt)], which were synthesized from reactions of [Rh(TPP)Cl] and [Co(TPP)] with [L
OEtRu(N)Cl
2] respectively, features unsymmetrical Ru≡N‐M’ units. The redox properties of the above nitrido‐bridged
heterometallic porphyrins complexes have been investigated using cyclic voltammetry. [(H
2O)(por)M(μ‐N)RuCl
2(L
OEt)] (M = Ru, Os, Fe) can catalyze styrene oxidation with PhIO, presumably via high‐valent μ‐nitrido oxo intermediates. Reactions of [(H
2O)(por)M(μ‐N)RuCl
2(L
OEt)] (M = Ru, Os, Fe; por = TTP or TPP) with AgOTf or AgBF
4 yielded the dimeric or polymeric M(IV)‐Ag(I)‐Ru(IV) complexes (M = Fe, Ru and Os).
Reaction of the Re(V) nitride [L
OEtRe(N)(PPh
3)Cl] with [Rh
2(OAc)
4] (OAc
- = acetate) gave [L
OEtRe(PPh
3)(Cl)(μ‐N)]
2Rh
2(OAc)
4 featuring a Rh‐N donor‐acceptor type interaction. [L
OEtRe(PPh
3)(Cl)(μ‐N)]
2Rh
2(OAc)
4 can be oxidized by [Cp
2Fe][PF
6] to give cationic [{L
OEtRe(PPh
3)(Cl)(μ‐N)}
2Rh
2(OAc)
4][PF
6]
2. By contrast, the binding of less nucleophilic [L
OEtRu(N)Cl
2] or [L
OEtOs(N)Cl
2] to Rh
2(OAc)
4 is reversible. Treatment of [Rh
2(Me
2pz)
4] (Me
2pz = 3,5‐dimethylpyrazolate) with two equivalents of [L
OEtRu(N)Cl
2] led to isolation of [L
OEtRuCl
2(μ‐N)]
2Rh
2(Me
2pz)
4 that can be described as a Ru
VI≡N−Rh
II‐Rh
II−N≡Ru
VI complex with some delocalization in the Rh‐N‐Ru units.
Metal complexes in sulfur‐rich ligand environments are of importance due to their
relevance to the active sites of heterogeneous catalysts and metalloenzymes. In the second
part of the thesis, we report the synthesis, structures and reactivity of group 8 and 9
complexes with thiocarbonyl and chelating thiolate ligands. [Ru(CS){N(Pr
i2
PQ)
2}
2] and cis‐[Os(CS)(PPh
3){N(Pr
i2
PS)
2}
2], synthesized from the reactions of [Ru
2(CS)
2(PPh
3)
4Cl
4] and [Os(CS)(PPh
3)
3Cl
2] with K[N(Pr
i2PQ)
2] respectively, could be protonated to [Ru(CS){HN(Pr
i2PS)
2}
2][BF
4]
2 and [Os(CS)(PPh
3){HN(Pr
i2PS)
2}{N(Pr
i2PS)
2}][BF
4] by Ph
3CBF
4. The group 9 analogues [M(CS)(PPh
3){N(R
2PQ)
2}] (M = Rh, Ir), which were prepared from reactions of [M(CS)(PPh
3)
2Cl] with K[N(R
2PQ)
2] (R = Ph, Pr
i), reacted with MeOTf to give dinuclear complexes [M
2{N(Pr
i2PS)
2}
2(PPh
3)(μ‐S
2C
2CH
2CH
3)](OTf) (M = Rh, Ir), [Ir
2{N(Ph
2PS)
2}
2(PPh
3)
2{μ‐C(CH
3)S}
2(μ‐Cl)](OTf) and [Rh
2{N(Ph
2PS)
2}
2(PPh
3)
2{μ‐S
2C
2(CH
3)
2}](OTf)
2 derived from thioacetyl intermediates. Migratory insertion of methyl group to the thiocarbonyl group is a crucial step for the
formation of these dinuclear complexes.
Half‐sandwich chloride complexes [Cp*M(N^S)Cl] (M = Rh, Ir) bearing bulky
bis(4‐tert‐butylpbenyl)‐2‐pyridylmethanethioIate ligand [N^S]
‐ have been synthesized from
[Cp*MCl
2]
2 (M = Rh and Ir) and Li[N^S]. Subsequent chloride abstractions of these
complexes by Na[BAr
F4] (Ar
F = 3,5‐bis(trifluoromethyl)phenyl), AgOTf or TlPF
6 afforded the
dinuclear [Cp*M(N^S)]
2(X)
2 complexes (M = Rh, Ir; X = [BAr
F4]
‐, OTf
‐, or PF
6).
[Cp*Rh(N^S)]
2(BAr
F4)
2 can catalyze the hydrogenation of benzaldehyes under high pressure
of H
2, presumably involving heterolytic activation of H
2 at the Rh‐S bond and the formation of the protonated thiolate hydride Rh‐H/S‐H intermediate.
Two rhodium(III) complexes [Rh{N(Pr
i2PS)
2}{к
2S,кC‐N(Pr
i2
PS)(Pr
i(C
3H
6)PS)] and
[Rh{N(Bu
t2PS)
2}{к
2S,кC‐N(Bu
t2PS)(Bu
t(C
4H
8)PS)] with cyclometalated [N(R
2PS)
2]
‐ (R = Pr
i and Bu
t) ligands have been synthesized via C‐H bond activation of one methyl substituent in
[N(R
2PS)
2]
‐. The tridentate к
3‐C,S,S coordination mode is unprecedented for [N(R
2PS)
2]
‐ (R =
Pr
i and Bu
t) ligands.
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