基于半夹心Cp*Rh单元的超分子桥环和螺环化合物的构筑策略

桥环和螺环化合物是有机化学中常用的概念而在其他领域鲜有提及。在本研究中,我们将桥环和螺环的概念拓展至超分子化学领域中并提出了相应的构筑策略。在刚性直线型配体中引入额外的螯合位点,通过配位驱动、分步组装的方法合成了复杂的3个有机金属超分子桥环化合物[(Cp*Rh)₆(μ-η²-η²-C₂O₄)₂(μ-C₂O₄)(L^A)₂](OTf)₆(1)、[(Cp*Rh)₆(dhbq)₂(pyrazine)(L^A)₂](OTf)₈(2)和[(Cp*Rh)₆(tpphz)₂(bpea)(L^A)₂](OTf)₁₂(3),以及一个超分子螺环化合物(Cp*Rh)₁₂(bibzim)₃Ru (L^A)₃(L^B)₃](OTf)₁₀(PF₆)₄(4),其中L^A=3,3′-di (pyridin-4-yl)-2,2′-bipyridine,OTf^-=CF₃SO^3-,dhbq=2,5-dihydroxy-1,4-benzoquinone,tpphz=tetrapyrido[3,2-a∶2′,3′-c∶3″,2″-h∶2'',3''-j]phenazine,bpea=1,2-di (pyridin-4-yl) ethane,bibzim=2,2′-bisbenzimidazole,L^B=4,4′-di (pyridin-4-yl)-1,1′-biphenyl。并通过单晶X射线衍射的方法一一表征了它们的单晶结构。     

基于半夹心Cp*Rh单元的超分子桥环和螺环化合物的构筑策略

桥环和螺环化合物是有机化学中常用的概念而在其他领域鲜有提及。在本研究中,我们将桥环和螺环的概念拓展至超分子化学领域中并提出了相应的构筑策略。在刚性直线型配体中引入额外的螯合位点,通过配位驱动、分步组装的方法合成了复杂的3个有机金属超分子桥环化合物[(Cp*Rh)₆(μ-η²-η²-C₂O₄)₂(μ-C₂O₄)(L^A)₂](OTf)₆(1)、[(Cp*Rh)₆(dhbq)₂(pyrazine)(L^A)₂](OTf)₈(2)和[(Cp*Rh)₆(tpphz)₂(bpea)(L^A)₂](OTf)₁₂(3),以及一个超分子螺环化合物(Cp*Rh)₁₂(bibzim)₃Ru(L^A)₃(L^B)₃](OTf)₁₀(PF₆)₄(4),其中L^A=3,3''-di (pyridin-4-yl)-2,2''-bipyridine,OTf-=CF₃SO₃^-,dhbq=2,5-dihydroxy-1,4-benzoquinone,tpphz=tetrapyrido[3,2-a∶2'',3''-c∶3″,2″-h∶2‴,3‴-j]phenazine,bpea=1,2-di (pyridin-4-yl) ethane,bibzim=2,2''-bisbenzimidazole,L^B=4,4''-di (pyridin-4-yl)-1,1''-biphenyl。并通过单晶X射线衍射的方法一一表征了它们的单晶结构。     

苯基或联苯基桥连双环戊二烯基铼羰基化合物的合成、结构及催化性能

两个单桥连的双环戊二烯（C₅Me₄H） E（C₅Me₄H）（E=C₆H₄,（C₆H₄）₂）分别与Re₂（CO）₁₀在均三甲苯中加热回流,得到了2个双核配合物（E）[（η⁵-C₅Me₄） Re（CO）₃]₂（E=C₆H₄（1）,（C₆H₄）₂（2））。通过元素分析、红外光谱、核磁共振氢谱和碳谱对配合物1和2的结构进行了表征,用X射线单晶衍射分析测定了配合物的结构。同时对2个配合物在芳香族化合物Friedel-Crafts酰基化反应中的催化活性进行了研究。     

苯基或联苯基桥连双环戊二烯基铼羰基化合物的合成、结构及催化性能

两个单桥连的双环戊二烯（C₅Me₄H）E（C₅Me₄H）（E=C₆H₄,（C₆H₄）₂）分别与Re₂（CO）₁₀在均三甲苯中加热回流,得到了2个双核配合物（E）[（η⁵-C₅Me₄）Re（CO）₃]₂（E=C₆H₄（1）,（C₆H₄）₂（2））。通过元素分析、红外光谱、核磁共振氢谱和碳谱对配合物1和2的结构进行了表征,用X射线单晶衍射分析测定了配合物的结构。同时对2个配合物在芳香族化合物Friedel-Crafts酰基化反应中的催化活性进行了研究。     

烃基取代茚基钌羰基化合物的合成及晶体结构

配体C₉H₇R(R=CH₂CH₂CH₃ (1),CH₂(CH₃)₂ (2),C₅H₉ (3),CH₂C₆H₅ (4),CH₂CH=CH₂ (5))分别与Ru₃(CO)12在二甲苯或庚烷中加热回流,得到了6个双核配合物[(η⁵-C₉H₆R)Ru(CO)(μ-CO)]₂(R=CH₂CH₂CH₃ (6),CH₂(CH₃)₂ (7),C₅H₈ (8),CH₂C₆H₅ (9),CH₂CH=CH₂ (10))和[(η⁵-C₉H₆)(H₃CH₂C)CHCH(CH₂CH₃)(η⁵-C₉H₆)] [Ru(CO)(μ-CO)]₂ (11).通过元素分析、红外光谱、核磁共振氢谱对配合物的结构进行了表征,并用X-射线单晶衍射法测定了配合物6,9,10和11的结构.     

芳基取代茚基钌羰基化合物的合成及晶体结构

配体C₉H₇R(R=Ph (1),4-tolyl (2),4-chlorophenyl (3),4-methoxyphenyl (4),2-thienyl (5))分别与Ru₃(CO)₁₂在甲苯或二甲苯中加热回流,得到了5个双核配合物[(η⁵-C₉H₆R)Ru(CO)]₂(μ-CO)₂(R=Ph (6),4-tolyl (7),4-chlorophenyl (8),4-methoxyphenyl (9),2-thienyl (10))。通过元素分析、红外光谱、核磁共振氢谱对配合物的结构进行了表征,并用X-射线单晶衍射法测定了配合物6,7和10的结构。     

芳基取代茚基钌羰基化合物的合成及晶体结构

配体C₉H₇R(R=Ph(1),4-tolyl(2),4-chlorophenyl(3),4-methoxyphenyl(1),2-thienyl(5))分别与Ru₃(CO)₁₂在甲苯或二甲苯中加热回流,得到了5个双核配合物[(η⁵-C₉H₆R)Ru(CO)]₂(μ-CO)₂(R=Ph(6),4-tolyl(7),4-chlorophenyl(8),4-methoxyphenyl(9),2-thienyl(10))。通过元素分析、红外光谱、核磁共振氢谱对配合物的结构进行了表征,并用X-射线单晶衍射法测定了配合物6,7和10的结构。     

含螯合二硫代碳硼烷配体的16电子Cp*Co半夹心化合物与炔酮的反应性

由于闭式碳硼烷(CB₁₁H₁₂^-和 C₂B₁₀H₁₂)丰富的化学, 它们已引了人们很多的关注. 半夹芯16e化合物Cp^#M(E₂C₂B₁₀H₁₀) (Cp# = η5-C₅H₅, η5-C₅Me₅; M = Co, Rh, Ir; E = S, Se)和半夹芯16e化合物(p-cymene)M(E₂C₂B₁₀H₁₀) (M = Ru, Os; E = S, Se) 具有相似的结构特点, 即含有一个二硫(硒)代闭式碳硼烷配体. 由于分子结构中都存在不饱和的16e金属中心、两个配位多样的S(Se)原子及B?H键可活化的碳硼烷笼子, 这些半夹芯式有机金属16e化合物已展现了丰富多样的反应性. 由此, 人们合成了一系列结构新颖的有机金属碳硼烷化合物. 目前, Kang SO课题组, Herberhold M课题组及燕红课题组已广泛研究并报道了半夹芯式含[E₂C₂B₁₀H₁₀]^2- (E = S, Se)配体的有机金属16e化合物与炔烃配体R₁C≡CR₂ (R₁ = H, CO₂Me; R₂ = Ph, Fc, CO₂Me, etc.)的反应性. 本文报道了半夹心16e化合物, Cp*Co(S₂C₂B₁₀H₁₀) (1) (Cp* = pentamethylcyclopentadienyl), 与炔酮HC≡C–C(O)R (R = OMe, Me, Ph)的反应性. (1)Cp*Co(S₂C₂B₁₀H₁₀)与过量的丙炔酸甲酯(HC≡C–CO₂Me)反应产生了五个18e化合物2~6. 其中, 2是在碳硼烷B(3)/B(6) 位点发生取代反应的产物, 其分子结构含有B–CH₂结构单元. 有趣的是, 化合物3~6则是通过两分子的炔烃在一个Co?S键上分别以头尾、头头、尾尾及尾头方式发生双分子加成的产物, 为四个几何同分异构体, 且它们首次从此类反应体系中同时分离得到. (2)Cp*Co(S₂C₂B₁₀H₁₀)与过量的3-丁炔-2-酮(HC≡C–C(O)Me)反应产生了化合物7和8. 这两个半夹心式18e化合物是通过两分子的炔烃在一个Co-S键上分别以头尾和头头方式发生双分子加成的产物. (3)Cp*Co(S₂C₂B₁₀H₁₀)与过量的苯基乙炔基酮(HC≡C–C(O)Ph)反应产生了化合物9和10. 化合物9和10的分子结构与化合物7和8类似, 即含有一个六圆环结构单元(Co–C=C–C=C–S). 化合物3, 7, 9及4, 8, 10代表了两类更稳定构像. 因此, 在上述反应中, 半夹芯式16e化合物Cp*Co(S₂C₂B₁₀H₁₀)展现出了其独特的反应性, 这也有利于我们理解结构单元Cp*Co和CpCo之间的差别对这类半夹芯式16e化合物反应性的影响.     

基于两个取代四甲基环戊二烯基配体的金属羰基化合物的合成及晶体结构

配体[C₅Me₄HR][R=4-BrPh(1),(MeC₅H₃N)CH₂(2)]分别与Mo(CO)₆,Ru₃(CO)₁₂和Fe(CO)₅在二甲苯中加热回流,得到了6个双核配合物trans-[η⁵-C₅Me₄R]₂Mo₂(CO)₆(3,4),trans-[(η⁵-C₅Me₄R)Ru(CO)(μ-CO)]₂(5,6)和trans-[η⁵-(C₅Me₄R)Fe(CO)(μ-CO)]₂(7,8,).通过元素分析、红外光谱、核磁共振氢谱对配合物的结构进行了表征,并用X-射线单晶衍射法测定了配合物3,5,6和8的结构.     

半夹心结构含1, 2-二硒碳硼烷的多核Co配合物的合成及结构表征

在氩气保护下,以邻位-碳硼烷、正丁基锂、硒粉和CpCo（CO）I₂为起始原料,合成、分离得到配合物CpCo（Se₂C₂B₁₀H₁₀）（1）、（CpCo）₂（Se₂C₂B₁₀H₁₀）（2）和（CpCo）₄（μ₃-Se）₄Co₂（μ₃-Se₂C₂B₁₀H₁₀）₄Co·CH₂Cl₂（3）,并用元素分析、质谱、IR、¹H NMR及X-射线单晶衍射对配合物（3）进行了表征。晶体属正交晶系,空间群P2₁2₁2₁,其晶胞参数为：a=1.30720（13）nm,b=1.39137（11）nm,c=3.88533（15）nm,β=90°,Z=4,V=7.0666（9）nm³,μ=7.890mm^-1,D_c=2.138g·cm^-3,F（000）=4268,R₁=0.0543,wR₂=0.1363。配合物中4个（Se₂C₂B₁₀H₁₀）^2-配体和4个单硒基团形成了1个Co₇Se₁₂核。     

Chemistry of Diruthenium and Dirhodium Analogues of Pentaborane(9): Synthesis and Characterization of Metal N,S‐Heterocyclic Carbene and B‐Agostic Complexes

Building upon our earlier results on the synthesis of electron‐precise transition‐metal–boron complexes, we continue to investigate the reactivity of pentaborane(9) and tetraborane(10) analogues of ruthenium and rhodium towards thiazolyl and oxazolyl ligands. Thus, mild thermolysis of nido‐[(Cp*RuH)₂B₃H₇] ( 1 ) with 2‐mercaptobenzothiazole (2‐mbtz) and 2‐mercaptobenzoxazole (2‐mboz) led to the isolation of Cp*‐based (Cp*=η⁵‐C₅Me₅) borate complexes 5 a , b [Cp*RuBH₃L] ( 5 a : L=C₇H₄NS₂; 5 b : L=C₇H₄NOS)) and agostic complexes 7 a , b [Cp*RuBH₂(L)₂], ( 7 a : L=C₇H₄NS₂; 7 b : L=C₇H₄NOS). In a similar fashion, a rhodium analogue of pentaborane(9), nido‐[(Cp*Rh)₂B₃H₇] ( 2 ) yielded rhodaboratrane [Cp*RhBH(L)₂], 10 (L=C₇H₄NS₂). Interestingly, when the reaction was performed with an excess of 2‐mbtz, it led to the formation of the first structurally characterized N,S‐heterocyclic rhodium‐carbene complex [(Cp*Rh)(L₂)(1‐benzothiazol‐2‐ylidene)] ( 11 ) (L=C₇H₄NS₂). Furthermore, to evaluate the scope of this new route, we extended this chemistry towards the diruthenium analogue of tetraborane(10), arachno‐[(Cp*RuCO)₂B₂H₆] ( 3 ), in which the metal center possesses different ancillary ligands.     

Metal-induced B—H activation in Cp*Rh,Cp*Ir, (p-cymene)Ru,and (p-cymene)Os half-sandwich complexes containing the 1,2-dicarba-closo-dodecaborane(12)-1,2-dichalcogenolato ligand

The reactivity of the 16e half-sandwich complexes Cp*Rh[E₂C₂(B₁₀H₁₀)] (1a,b), Cp*Ir[E₂C₂(B₁₀H₁₀)] (2a,b) (E = S (a), Se(b)), (p-cymene)Ru[S₂C₂(B₁₀H₁₀)] (3), (p-cymene)Os[S₂C₂(B₁₀H₁₀)] (4) (p-cymene = 1-Me-4-Prⁱ-benzene) towards various alkynes (acetylene, propyne, 3-methoxypropyne, methyl acetylenemonocarboxylate, dimethyl acetylenedicarboxylate, phenylacetylene, ferrocenylacetylene) was studied. The reactions start with an insertion into one of the M—E bonds, followed (except for MeO₂C—CC—CO₂Me) by intramolecular, metal-induced B—H activation, formation of an M—B bond, accompanied by simultaneous transfer of a hydrogen atom from boron via the metal atom to the alkyne. This leads to new complexes with a cisoidor transoid geometry (orientation of the E—C=C unit with respect to the C(1)—B bond). This geometry determines the course of further intramolecular reactions which lead selectively to carboranes mono- or disubstituted in B(3,6) positions. Numerous intermediates and final products were characterized by X-ray analysis in the solid state, and by multinuclear magnetic resonance in solution. First catalytic applications of 1a,b became evident by cyclotrimerization reactions.     

Chemistry of N,S‐Heterocyclic Carbene and Metallaboratrane Complexes: A New η3‐BCC‐Borataallyl Complex

A high‐yielding synthetic route for the preparation of group 9 metallaboratrane complexes [Cp*MBH(L)₂], 1 and 2 ( 1 , M=Rh, 2 , M=Ir; L=C₇H₄NS₂) has been developed using [{Cp*MCl₂}₂] as precursor. This method also permitted the synthesis of an Rh–N,S‐heterocyclic carbene complex, [(Cp*Rh)(L₂)(1‐benzothiazol‐2‐ylidene)] ( 3 ; L=C₇H₄NS₂) in good yield. The reaction of compound 3 with neutral borane reagents led to the isolation of a novel borataallyl complex [Cp*Rh(L)₂B{CH₂C(CO₂Me)}] ( 4 ; L=C₇H₄NS₂). Compound 4 features a rare η³‐interaction between rhodium and the B‐C‐C unit of a vinylborane moiety. Furthermore, with the objective of generating metallaboratranes of other early and late transition metals through a transmetallation approach, reactions of rhoda‐ and irida‐boratrane complexes with metal carbonyl compounds were carried out. Although the objective of isolating such complexes was not achieved, several interesting mixed‐metal complexes [{Cp*Rh}{Re(CO)₃}(C₇H₄NS₂)₃] ( 5 ), [Cp*Rh{Fe₂(CO)₆}(μ‐CO)S] ( 6 ), and [Cp*RhBH(L)₂W(CO)₅] ( 7 ; L=C₇H₄NS₂) have been isolated. All of the new compounds have been characterized in solution by mass spectrometry, IR spectroscopy, and ¹H, ¹¹B, and ¹³C NMR spectroscopies, and the structural types of 4 – 7 have been unequivocally established by crystallographic analysis.     

The Versatile Coordination Modes of Monophosphine‐o‐Carborane in the Formation of Iridium and Rhodium Complexes: Synthesis,Reactivity, and Characterization

Monophosphine‐o‐carborane has four competitive coordination modes when it coordinates to metal centers. To explore the structural transitions driven by these competitive coordination modes, a series of monophosphine‐o‐carborane Ir,Rh complexes were synthesized and characterized. [Cp*M(Cl)₂{1‐(PPh₂)‐1,2‐C₂B₁₀H₁₁}] (M=Ir ( 1 a ), Rh ( 1 b ); Cp*=η⁵‐C₅Me₅), [Cp*Ir(H){7‐(PPh₂)‐7,8‐C₂B₉H₁₁}] ( 2 a ), and [1‐(PPh₂)‐3‐(η⁵‐Cp*)‐3,1,2‐MC₂B₉H₁₀] (M=Ir ( 3 a ), Rh ( 3 b )) can be all prepared directly by the reaction of 1‐(PPh₂)‐1,2‐C₂B₁₀H₁₁ with dimeric complexes [(Cp*MCl₂)₂] (M=Ir, Rh) under different conditions. Compound 3 b was treated with AgOTf (OTf=CF₃SO₃^?) to afford the tetranuclear metallacarborane [Ag₂(thf)₂(OTf)₂{1‐(PPh₂)‐3‐(η⁵‐Cp*)‐3,1,2‐RhC₂B₉H₁₀}₂] ( 4 b ). The arylphosphine group in 3 a and 3 b was functionalized by elemental sulfur (1 equiv) in the presence of Et₃N to afford [1‐{(S)PPh₂}‐3‐(η⁵‐Cp*)‐3,1,2‐MC₂B₉H₁₀] (M=Ir ( 5 a ), Rh ( 5 b )). Additionally, the 1‐(PPh₂)‐1,2‐C₂B₁₀H₁₁ ligand was functionalized by elemental sulfur (2 equiv) and then treated with [(Cp*IrCl₂)₂], thus resulting in two 16‐electron complexes [Cp*Ir(7‐{(S)PPh₂}‐8‐S‐7,8‐C₂B₉H₉)] ( 6 a ) and [Cp*Ir(7‐{(S)PPh₂}‐8‐S‐9‐OCH₃‐7,8‐C₂B₉H₉)] ( 7 a ). Compound 6 a further reacted with nBuPPh₂, thereby leading to 18‐electron complex [Cp*Ir(nBuPPh₂)(7‐{(S)PPh₂}‐8‐S‐7,8‐C₂B₉H₁₀)] ( 8 a ). The influences of other factors on structural transitions or the formation of targeted compounds, including reaction temperature and solvent, were also explored.     

Versatile reactivity of half-sandwich Ir and Rh complexes toward carboranylamidinates and their derivatives: synthesis, structure, and catalytic activity for norbornene polymerization

Synthesis, structure, and reactivity of carboranylamidinate‐based half‐sandwich iridium and rhodium complexes are reported for the first time. Treatment of dimeric metal complexes [{Cp*M(μ‐Cl)Cl}₂] (M=Ir, Rh; Cp*=η⁵‐C₅Me₅) with a solution of one equivalent of nBuLi and a carboranylamidine produces 18‐electron complexes [Cp*IrCl(Cab^N‐DIC)] ( 1 a ; Cab^N‐DIC=[iPrN?C(closo‐1,2‐C₂B₁₀H₁₀)(NHiPr)]), [Cp*RhCl(Cab^N‐DIC)] ( 1 b ), and [Cp*RhCl(Cab^N‐DCC)] ( 1 c ; Cab^N‐DCC=[CyN?C(closo‐1,2‐C₂B₁₀H₁₀)(NHCy)]). A series of 16‐electron half‐sandwich Ir and Rh complexes [Cp*Ir(Cab^N′‐DIC)] ( 2 a ; Cab^N′‐DIC=[iPrN?C(closo‐1,2‐C₂B₁₀H₁₀)(NiPr)]), [Cp*Ir(Cab^N′‐DCC)] ( 2 b , Cab^N′‐DCC=[CyN?C(closo‐1,2‐C₂B₁₀H₁₀)(NCy)]), and [Cp*Rh(Cab^N′‐DIC)] ( 2 c ) is also obtained when an excess of nBuLi is used. The unexpected products [Cp*M(Cab^N,S‐DIC)], [Cp*M(Cab^N,S‐DCC)] (M=Ir 3 a , 3 b ; Rh 3 c , 3 d ), formed through BH activation, are obtained by reaction of [{Cp*MCl₂}₂] with carboranylamidinate sulfides [RN?C(closo‐1,2‐C₂B₁₀H₁₀)(NHR)]S^? (R=iPr, Cy), which can be prepared by inserting sulfur into the C? Li bond of lithium carboranylamidinates. Iridium complex 1 a shows catalytic activities of up to 2.69×10⁶ g_PNB ${{\rm{mol}}_{{\rm{Ir}}}^{ - {\rm{1}}} }Synthesis, structure, and reactivity of carboranylamidinate-based half-sandwich iridium and rhodium complexes are reported for the first time. Treatment of dimeric metal complexes [{Cp*M(μ-Cl)Cl}(2)] (M = Ir, Rh; Cp* = η(5)-C(5)Me(5)) with a solution of one equivalent of nBuLi and a carboranylamidine produces 18-electron complexes [Cp*IrCl(Cab(N)-DIC)] (1?a; Cab(N)-DIC = [iPrN=C(closo-1,2-C(2)B(10)H(10))(NHiPr)]), [Cp*RhCl(Cab(N)-DIC)] (1?b), and [Cp*RhCl(Cab(N)-DCC)] (1?c; Cab(N)-DCC = [CyN=C(closo-1,2-C(2)B(10)H(10))(NHCy)]). A series of 16-electron half-sandwich Ir and Rh complexes [Cp*Ir(Cab(N')-DIC)] (2?a; Cab(N')-DIC = [iPrN=C(closo-1,2-C(2)B(10)H(10))(NiPr)]), [Cp*Ir(Cab(N')-DCC)] (2?b, Cab(N')-DCC = [CyN=C(closo-1,2-C(2)B(10)H(10)(NCy)]), and [Cp*Rh(Cab(N')-DIC)] (2?c) is also obtained when an excess of nBuLi is used. The unexpected products [Cp*M(Cab(N,S)-DIC)], [Cp*M(Cab(N,S)-DCC)] (M = Ir 3?a, 3?b; Rh 3?c, 3?d), formed through BH activation, are obtained by reaction of [{Cp*MCl(2)}(2)] with carboranylamidinate sulfides [RN=C(closo-1,2-C(2)B(10)H(10))(NHR)]S(-) (R = iPr, Cy), which can be prepared by inserting sulfur into the C-Li bond of lithium carboranylamidinates. Iridium complex 1?a shows catalytic activities of up to 2.69×10(6) g(PNB) mol(Ir)(-1) h(-1) for the polymerization of norbornene in the presence of methylaluminoxane (MAO) as cocatalyst. Catalytic activities and the molecular weight of polynorbornene (PNB) were investigated under various reaction conditions. All complexes were fully characterized by elemental analysis and IR and NMR spectroscopy; the structures of 1?a-c, 2?a, b; and 3?a, b, d were further confirmed by single crystal X-ray diffraction.     

Synthesis and characterization of heterometallic Rh/Ru complexes supported by 1,2-dichalcogenolato-o-carborane ligands

The 16-electron half-sandwich complexes Cp^∗Rh[E₂C₂(B₁₀H₁₀)] (E = S, 1a; Se, 1b) react with [Ru(COD)Cl₂]_x under different conditions to give different types of heterometallic complexes. When the reactions were carried out in THF for 24 h, the binuclear Rh/Ru complexes [Cp^∗Rh(μ-Cl)₂(COD)Ru][E₂C₂(B₁₀H₁₀)] (E = S, 2a; Se, 2b) bridged by two Cl atoms and the binuclear Rh/Rh complexes (Cp^∗Rh)₂[E₂C₂(B₁₀H₁₀)] (E = S, 3a; Se, 3b) with direct Rh-Rh bond can be isolated in moderate yields. [Ru(COD)Cl₂] fragments in 2a and 2b have inserted into the Rh-E bond. If the [Ru(COD)Cl₂]_x was reacted with 1a in the presence of K₂CO₃ in methanol solution, the product [Cp^∗Rh(COD)]Ru[S₂C₂(B₁₀H₁₀]] (4a), K[(μ-Cl)(μ-OCH₃)Ru(COD)]₄ (5a) and 3a were obtained. The B(3)-H activation in complex 4a was found. However, when the reaction between 1b and [Ru(COD)Cl₂]_x was carried out in excessive NaHCO₃, the carborane cage opened products {Cp^∗Rh[S₂C₂(B₉H₁₀)]}Ru(COD) (6b), {Cp^∗Rh[S₂C₂(B₉H₉)]}Ru(COD)(OCH₃) (7b) and 3b were obtained. All complexes were fully characterized by their IR, ¹H NMR and elemental analyses. The molecular structures of 2a, 2b, 3b, 4a, 5a, and 7b have been determined by X-ray crystallography.     

Demethylation of the SMe2 substituent in metallacarboranes. Synthesis and structures of the complexes Cp*M(η-9-SMe-7,8-C2B9H10) (M = Rh, Ir)

The demethylation of the cations [Cp*M(??-9-SMe₂-7,8-C₂B₉H₁₀)]⁺ (1a,b) with PhCH₂SNa affords neutral metallacarboranes Cp*M(??-9-SMe-7,8-C₂B₉H₁₀) (2a: M = Rh; 2b: M = Ir). The reverse reaction can be performed by the treatment of complexes 2a,b with MeI in the presence of TlPF₆. The structures of complexes 2a,b were determined by X-ray diffraction.     

Synthesis and characterization of hetero-binuclear Co-Rh complexes [CpCoS2C2(B9H10)][Rh(COD)] and [CpCoSe2C2(B10H10)][Rh(COD)]

Two hetero-binuclear complexes [Cp^∗CoS₂C₂(B₉H₁₀)][Rh(COD)] (2a) and [Cp^∗CoSe₂C₂(B₁₀H₁₀)][Rh(COD)] (2b) [Cp^∗ = η⁵-pentamethylcyclopentadienyl, COD = cyclo-octa-1,5-diene (C₈H₁₂)] were synthesized by the reactions of half-sandwich complexes [Cp^∗CoE₂C₂(B₁₀H₁₀)] [E = S (1a), Se (1b)] with low valent transition metal complexes [Rh(COD)(OEt)]₂ and [Rh(COD)(OMe)]₂. Although the reaction conditions are the same, the structures of two products for dithiolato carborane and diselenolato carborane are different. The cage of the carborane in 2a was opened; However, the carborane cage in 2b was intact. Complexes 2a and 2b have been fully characterized by ¹H, ¹¹B NMR and IR spectroscopy, as well as by elemental analyses. The molecular structures of 2a and 2b have been determined by single-crystal X-ray diffraction analyses and strong metal-metal interactions between cobalt and rhodium atoms (2.6260 Å (2a) and 2.7057 Å (2b)) are existent.     

Synthesis and characterization of half-sandwich iridium(III) and rhodium(III) complexes bearing organochalcogen ligands

Reactions of [Cp*M(μ-Cl)Cl]₂ (M = Ir, Rh; Cp* = η⁵-pentamethylcyclopentadienyl) with bi- or tri-dentate organochalcogen ligands Mbit (L1), Mbpit (L2), Mbbit (L3) and [Tm^Me]⁻ (L4) (Mbit = 1,1′-methylenebis(3-methyl-imidazole-2-thione); Mbpit = 1,1′-methylene bis (3-iso-propyl-imidazole-2-thione), Mbbit = 1,1′-methylene bis (3-tert-butyl-imidazole-2-thione)) and [Tm^Me]⁻ (Tm^Me = tris (2-mercapto-1-methylimidazolyl) borate) result in the formation of the 18-electron half-sandwich complexes [Cp*M(Mbit)Cl]Cl (M = Ir, 1a; M = Rh, 1b), [Cp*M(Mbpit)Cl]Cl (M = Ir, 2a; M = Rh, 2b), [Cp*M(Mbbit)Cl]Cl (M = Ir, 3a; M = Rh, 3b) and [Cp*M(Tm^Me)]Cl (M = Ir, 4a; M = Rh, 4b), respectively. All complexes have been characterized by elemental analysis, NMR and IR spectra. The molecular structures of 1a, 2b and 4a have been determined by X-ray crystallography.     

LIGAND EXCHANGE AND LIGAND TRADING IN TRANS-[PtX2(OLEFIN) (PYRIDINE)] COMPLEXES

Abstract

The ¹H nmr spectra of freshly prepared CDCl₃ solutions of the complexes trans-[PtCl₂(olefin)(L)], where L is pyridine or a substituted pyridine, show no coupling between ^{1 9 5}Pt and the α protons of pyridine (³J_pt–NCH) owing to rapid exchange of complexed L with free L. On standing, the adventitious free L is gradually consumed by formation of trans-[PtCl₂(L)₂] and the spectra of the aged solutions show the coupling. When CDCl, solutions of [PtBr₂(Ol_b)(L_b)] and [PtCl₂(Ol_a)(L_a)], where Ol_a =C₂H₄, are mixed, a total of 6 ethylene complexes can be identified in solution. Accordingly halogen trading, Ol trading or/and L trading occurs and the solution probably contains a total of 12 complexes.