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Russell N. Grimes

Publications and source records attributed to Russell N. Grimes.

6 recordsLinked to original sources
PubMed2001

nido<-->closo Interconversion of Six-Vertex Metallacarboranes: Access to CoC(2)B(3) and CoC(2)B(4) Clusters with Nonadjacent Carbon Atoms Organotransition-Metal Metallacarboranes, part 57. This work was supported in part by the National Science Foundation (grant CHE 9980708) and the Alexander von Humboldt Foundation (Feodor Lynen postdoctoral fellowship to H.-J. Schanz). Part 56: M. Bluhm, H. Pritzkow, W. Siebert, R. N. Grimes, Angew. Chem. 2000, 112, 4736; Angew. Chem. Int. Ed. 2000, 39, 4562.

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Journal Article↗
PubMed1998

New Metallacarborane Chemistry: Molybdenum and Tungsten Carbonyl Multidecker Sandwiches. Cluster Dimers Linked via Metal-Metal Bonds(1).

This article reports the synthesis, characterization, and chemistry of the first molybdenum and tungsten complexes bearing small carborane ligands, including novel M-M-linked dicluster species. The reaction of the nido-2,3-Et(2)C(2)B(4)H(4)(2)(-) dianion with (RCN)(3)M(CO)(3) reagents (M = Mo, W; R = Me, Et) gave the (Et(2)C(2)B(4)H(4))M(CO)(3)(2)(-) anions, which were isolated as lithium (12-crown-4) salts 1b (M = Mo) and 2b (M = W). Treatment of 1b and 2b with Ph(4)PX (X = Cl, Br, I) followed by triflic acid afforded the dimeric products [(Et(2)C(2)B(4)H(4))Mo(CO)(2)](2)(&mgr;-X)(2) (X = Cl (3a), Br (3b), I (3c)) and the corresponding tungsten dimers 4a-c, all of which are red or orange air-stable crystalline solids. X-ray crystallography on 3b revealed a geometry without precedent in small metallacarborane dimers, in which two MC(2)B(4) pentagonal pyramidal clusters are linked via an intercluster metal-metal bond. From NMR and other spectroscopic evidence, the remaining dimeric products 3a, 3c, and 4a-c are proposed to have structures similar to 3b. Decapitation of 3b with HCl/EtOAc in THF gave red solid [(Et(2)C(2)B(3)H(5))Mo(CO)(2)](2)(&mgr;-Br)(2) (5), which is proposed to have two open planar C(2)B(3) end rings and, hence, is a potential building block for linear polymers via deprotonation and metal-ion-stacking reactions. Compound 3b was also generated in a different reaction, involving the nido-Et(2)C(2)B(4)H(5)(-) anion and [Mo(CO)(4)Br](2)[&mgr;-Br](2) which also produced the bis(carboranyl)molybdenum complex (Et(2)C(2)B(4)H(4))(2)Mo(CO)(2) (6), a nearly colorless solid for which a bent sandwich structure is postulated. The reaction of the nido-cobaltacarborane anion CpCo(Et(2)C(2)B(3)H(4))(-) with [Mo(CO)(4)Cl](2)[&mgr;-Cl](2) in toluene gave two isolable products, red CpCo(Et(2)C(2)B(3)H(3))Mo(CO)(4) (7) and dark red [CpCo(Et(2)C(2)B(3)H(3))](2)Mo(CO)(2) (8), which have, respectively, triple-decker and bent-tetradecker sandwich structures based on X-ray crystallographic structure determinations. The reaction of CpCo(Et(2)C(2)B(3)H(4))(-) with [Mo(CO)(4)Br](2)[&mgr;-Br](2) in toluene gave 8 and a known fused-cluster complex Cp(2)Co(2)(Et(4)C(4)B(6)H(6)) (9). Treatment of the CpCo(Et(2)C(2)B(3)H(4))(-) anion with [W(CO)(4)Br](2)[&mgr;-Br](2) afforded red crystalline CpCo(Et(2)C(2)B(3)H(3))W(CO)(4) (10), which on reaction with PhLi followed by Me(3)OBF(4) gave 11, a B(5)-benzyl derivative of 10. X-ray diffraction analyses established triple-decker sandwich structures for both compounds. The new products were characterized by multinuclear NMR, IR, UV-vis, and mass spectroscopy, and elemental analysis, supplemented by electrochemical data on 3b, 8, and 11.

Journal Article↗
PubMed1997

Apically Linked Small Metallacarborane Clusters. Directed Synthesis and Structural Characterization of 7,7'-[CpCo(2,3-Et(2)C(2)B(4)H(3)](2) and [CpCo(2,3-Et(2)C(2)B(4)H(3)-7)](2)X Complexes (X = MeCH, HC=CH, C&tbd1;C)(,)(1).

A series of novel bis(cobaltacarboranyl) (CoC(2)B(4))(2)X dicluster complexes whose B(7) (apex) atoms are linked by organic moieties involving sp-, sp(2)-, or sp(3)-hybridized carbon, or by a direct B(7)-B(7') bond, has been prepared by extension of the recently described "recapitation" method (Curtis, M. A.; et al. Inorg. Chem. 1996, 35, 6703) that entails treatment of 6-vertex nido-CoC(2)B(3) dianions with monoboron reagents. Reactions of Li(2)[nido-CpCo(Et(2)C(2)B(3)H(3))] in toluene with MeCH(BCl(2))(2) and with cis-(BCl(2))C(2)H(2) gave, respectively, [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)MeCH (5) and cis-[CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)C(2)H(2) (6a) following chromatographic separation. Ultraviolet irradiation of 6a induced partial conversion to the trans isomer 6b, affording a 46:54 trans/cis equilibrium mixture in 84 h. Reactions of the same cobaltacarborane dianion with bis(catecholboryl)acetylene and with bis(catecholdiboryl) gave [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)C(2) (7) and [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2) (8), respectively. The new complexes were isolated as air-stable, crystalline orange solids and were characterized from their (1)H, (11)B, and (13)C NMR, IR, UV-visible, and mass spectra, supported by X-ray crystallographic studies of 5, 6a, 7, and 8. Crystal data for 5: space group P2(1)ca (orthorhombic); a = 14.220(10) Å, b = 15.690(10) Å, c = 16.860(10) Å, Z = 4; R = 0.041 for 7485 independent reflections. Crystal data for 6a: space group C2/c (monoclinic); a = 12.849(6) Å, b = 11.435(6) Å, c = 25.619(13) Å, beta = 96.230(10) degrees; Z = 4; R = 0.036 for 5440 independent reflections. Crystal data for 7: space group P2(1)/n (monoclinic); a = 17.298(12) Å, b = 13.932(10) Å, c = 30.82(2) Å, beta = 96.34(5) degrees; Z = 8; R = 0.070 for 9632 independent reflections. Crystal data for 8: space group P&onemacr; (triclinic); a = 9.150(10) Å, b = 10.270(10) Å, c = 10.340(10) Å, alpha = 84.52(5) degrees, beta = 78.05(5) degrees, gamma = 68.6(5) degrees; Z = 1; R = 0.056 for 5154 independent reflections.

Journal Article↗
PubMed1996

Organotransition-Metal Metallacarboranes. 46. Multidecker Sandwiches of the Cobalt Group Metals(,)(1).

The double-decker sandwich complex CpIr(2,3-Et(2)C(2)B(4)H(4)) (1a) was prepared via deprotonation of nido-2,3-Et(2)C(2)B(4)H(6) to its mono- or dianion and reaction with (CpIrCl(2))(2) in THF and isolated as a colorless air-stable solid; the B(4)-chloro derivative 1b was also obtained. Decapitation of 1a and 1b with TMEDA afforded colorless nido-CpIr(2,3-Et(2)C(2)B(3)H(5)) (2a) and its 4-chloro derivative 2b. Chlorination of 1a by Cl(2) or N-chlorosuccinimide gave the symmetrical species CpIr(2,3-Et(2)C(2)B(4)H(3)-5-Cl) (1c), which was decapped to yield nido-CpIr(2,3-Et(2)C(2)B(3)H(4)-5-Cl) (2c). The triple-decker complexes CpIr(2,3-Et(2)C(2)B(3)H(2)-4[6]-Cl)IrCp (3), an orange solid, and dark green CpIr(2,3-Et(2)C(2)B(3)H(2)-4[6]-Cl)CoCp (5) were prepared from 2a and nido-CpCo(2,3-Et(2)C(2)B(3)H(5)) (4a), respectively, by deprotonation and reaction with (CpIrCl(2))(2) in THF. Reaction of the 2c(-) anion with Rh(MeCN)(3)Cl(3) gave the dark green tetradecker complex [CpIr(Et(2)C(2)B(3)H(2)-5-Cl)](2)RhH (6). In an attempt to prepare a heterotrimetallic Co-Rh-Ir tetradecker sandwich, a three-way reaction involving the deprotonated anions derived from CpCo(2,3-Et(2)C(2)B(3)H(4)-5-Cl) (4b) and 2c with Rh(MeCN)(3)Cl(3) was conducted. The desired species CpCo(Et(2)C(2)B(3)H(2)Cl)RhH(Et(2)C(2)B(3)H(2)Cl)IrCp (7) and the tetradeckers [CpCo(Et(2)C(2)B(3)H(2)Cl)](2)RhH (8) and 6 were isolated in small quantities from the product mixture; many other apparent triple-decker and tetradecker products were detected via mass spectroscopy but were not characterized. All new compounds were isolated via column or plate chromatography and characterized via NMR, UV-visible, and mass spectroscopy and by X-ray crystal structure determinations of 1a and 3. Crystal data for 1a: space group C2/c; a = 28.890(5) Å, b = 8.511(2) Å, c = 15.698(4) Å, beta = 107.61(2) degrees; Z = 8; R = 0.049 for 1404 independent reflections having I > 3sigma(I). Crystal data for 3: space group P2(1)/c; a = 11.775(4) Å, b = 15.546(5) Å, c = 15.500(5) Å, beta = 103.16(3) degrees; Z = 4; R = 0.066 for 2635 independent reflections having I > 3sigma(I).

Journal Article↗
PubMed1996

"Recapitation" of nido-Metallacarboranes as a Synthetic Tool: Preparation of Apically Substituted CoC(2)B(4) Clusters via Boron Insertion(1).

Derivatives of CpCo(2,3-Et(2)C(2)B(4)H(4)) containing substituents at the apex boron atom [B(7)], the first examples of apically functionalized small metallacarborane clusters, have been prepared in good yield via boron insertion into the nido-CpCo(2,3-Et(2)C(2)B(3)H(3))(2-) dianion. Reaction of this substrate with BX(3) (X = Cl, Br, I) or PhBCl(2) in toluene at room temperature gave the corresponding CpCo(2,3-Et(2)C(2)B(4)H(3)-7-X) derivatives (2a-c and 3 in which X = Cl, Br, I, and Ph, respectively), all of which were isolated via column chromatography as air-stable yellow solids and characterized via (1)H, (11)B, and (13)C NMR, infrared, UV-visible, and mass spectra. Treatment of the same dianion with 1,4-(Br(2)B)(2)C(6)H(4) afforded air-stable orange crystalline [CpCo(2,3-Et(2)C(2)B(4)H(3)-7)](2)C(6)H(4) (4). The structure of this compound was defined via spectroscopy and X-ray crystallography as a bis(cobaltacarborane) complex linked at the apex borons via a 1,4-phenylene bridge. Crystal data for 4: space group Pbca; a = 15.056(7) Å, b = 21.612 (8) Å, c = 11.641 (3) Å; Z = 4; R = 0.045 for 1582 independent reflections having I > 3sigma(I).

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