Answers to problems Chapter 2 2-2 VB' b1u ; V13•14, b3u ; V I6.17.IB' b1u (b) Trap BlOHl4 at - 20 to - 78°, 2-3 Diagram very similar to Fig. 2-12 BsH9 at -95 to -126°, B2H6 at 2-4 B1H~+ might have such a struc­ -196° ture, not B1H6 (c) B2H6+Me3N --+ Me3N,BH3 2-5 (a, b) IH, 1111 quartet; 11B, 1331 (in volatile) +!BZH6 quartet 4-8 MezNH,BH3; Me1NB1Hs; (c) IH, 1111 quartet, 1234321 Me2NBH2; (Me1N}zBH; septet; 11 B 1331 quartet of doub­ B(NMe1)3 lets 4-15 1,2-Tetramethylenediborane (d) IH, as for (c), but intensities Hydrolysis --+ 4 :1, not 6:1; 11B 121 triplet of (HO}zB(CH2)4B(OH}z doublets B = Me3N,BH2(CH2)4BH2' NMe3 Chapter 3 4-16 A = B6HlO B = BsH9 3-1 a, 0; b,+t,-i-; c,f, O,+!, -!; C = B4HlO d,e, 1, -!; f, -i-, +i- 4-17 A = Me1 BH1 BH2 (b) a, -1; b, -!; c, 0, -!; d, B = (EtNBHh _.J. _1. 3' 6 C = trans- (Me2BN :CHMejz (c) -1,0, +! D = cis- (Me1BN :CHMe)z (d) B(l, 3, 6, 9), 0; B(2, 4), -~; B(5, 7, 8, 10), +t Chapter 5 3-3 (201O)B 1H 4 , (1020)B1H;-, 5-3 AHa = 4618kJ/mole (1012)B1HS", (1004)B2Hi, E(AIHB) = 395 kJ/mole (OO30)B2H~ -, (OO22)B2H~ -, 5-4 (a) Me2AIPh1AIMe1 (OO14)B2H~ -, etc. (b) reactants plus 3-4 (1301) and (221O)B4H 6, Me2AIBrClAIMe2 (4004)B4H 11. (1401) and (c)AI(BH4h +Me.B2H6-n (2301)B sH7, and (5013) and (d) AI( °Hh + methane (e,!) (4104)BsH 13 appear possible Me2AIMe(OBu')AIMe1 3-6 (2402) and (3311)B6HlO are 5-7 B, 97; AI, 78; Ga, 34 theoretically possible, as are (3303), (4212), (5121), and Chapter 6 (6030)B 6H 12. However, B6H12 6-1 1,2-; 1,7-; 2,3-; and should adopt an arachno­ 2,4-C2BSH7 structure based on a 6-2 1,2-; 1,6-; 2,3-; and 2,4- dodecahedron, not a nido­ Me2-1,6-C2 B4 H4 structure based on a pentagonal 1,2-; 1,3-; 1,4-; 1,6-; 3,4--; 3,5-; bipyramid (see Chapter 6). and 4,6-Me2-1,2--C2B4H4 6-3 cf carboranes, replacing CH by Chapter 4 NH+ 4-1 (a) x = 3p, Y = p, z = !(4p+q) 6-4 CB4HS", CBBHg, MeAIC2B4H6, (b) B2H6; (i) 574, (ii) 20·7: B4H 10 ; [(C2B4H6)2Fe(II)JZ- closo-; 1152, 21·6: BsH9; 1427, 22·6: CB4H~ -, nido-; C4B2H~ -, BsH11; 1453,22'1: B6HlO; 1718, arachno-; CBH;;-, cf ethane 23·0 6-6 1,3-Me2-1,2--C1B3H 3 4-2 Me3N, 117; Me3As, 121; Me2S, 120; Me2Se, 109; CO, 95; Me3P Chapter 7 (A H), 57 kJ/mole 7-2 (a) to (c), Me3C+ ; 4-3 (a) X = F, A H = 672; CI, 288; (d) Me2HCCMei ; Br, 228; 1,60 kJ/mole (e) Et3C+ (b) X = F, A H = 3924; CI, 7-3 cf FeS(CO)ISC (Fig. 5-25), with 1392; Br, 846; I, 114 kJ/mole apical Ru(COh, and 4 basal 4-4 (a) Trap B4HlO at -126°, B1Ho (CsHs)Ru units bridged by 4 at -196°; Tapler for H2 carbonyl groups Index Alkali metal alkyls, 140 C1BIOH'1' 155 Alkyls, associated metal, 122 metallocarboranes, 164 Aluminium, alkyls, 122 C1B4H~- complex, 169 carbide, A14C3, 147 C1B6H~- complex, 167 energies of Al-X bonds, 130 C1B7H~- complex, 167 halides, 125, 128 C1B8 Hi;;- complex, 167 hydride, 113 C1B9Hii complexes, 164 olefin interactions, 135 C3B3H6 complex, 170 trimethyl, 123 monocarba species, 170 triphenyl, 125 CB 5H 7 , CB5H9, 172 tristetrahydroborate, 116 CB9 H 1o, CB,oH~I' CBllH11, 171 tetracarba species (C4 B1H 6 ), 172 Beryllium, diboron octahydride, 119 tricarba species (C3B3H 7), 172 dimethyl, 139 Carbonium ions, 176 di-t-butyl, 115, 139 Copper(I) tetrahydroborate bis(tri-_ hydride, 115 phenylphosphine) adduct, 118 Bond eDergy terms, for Al-X bonds, Cyclopentadienyl complexes, 4, 192 130 for B-X bonds, 62 Borane adducts, 80 Diborane, bonding in, 14 Borane anions, BHi, 47, 75, 76, 93 preparation of, 69 B1Hi, 47, 78 pyrolysis of, 70 B3Hg, 47, 76, 93, 153 reactions, adduct formation, 77 BsHg,97 cleavage by HX, 82 B6H~ -, 55, 153 exchange reactions, 91 BsHs 1 -, 56, 153 hydroboration, 87 B9H14,103 oxidative cleavage, 92 BIOHi;;-, 56,106,153 reduction, 93 BIO HF,102 spectra of, infrared, 7 B,oH,i,104 n.m.r.,10 B12Hi2", 57, 93, 106, 153 photoelectron, 27 Borazine, 86 structure of, 13 Boron carbide, B12C3, 57 Boron halides, BX3, 69 Enthalpies of dissociation, of Al1X6, 130 B4 C14 ,53 of B2 H6• 63 BsCls,56 Enthalpies of formation, of AlX3, 130 Boron hydrides of BpHp+q> 62 B1 H 6, see 'Diborane B4H10, 34,41. 73,94 Ferrocene,4, 192 BsH9' 41, 47, 73, 96 Float valve, 65 B5H", 35, 41, 73, 98 B6 H 10' 37, 41, 73, 98 Gallium, hydride, 114 BIOH'4' 38,41,74,99 triphenyl, 138 others, 46 Hydrides, classified using the Periodic Calcium hexaboride, CaB6, 55 Table, 112 Carboranes, classification of, 150 Hydroboration, 87 dicarba species, 151 C1B 3H 5, C1B4H 6 , C1B 5H 7, 161 Indium, trimethyl, 137 C1 B4 H 8 ,161 triphenyl, 138 C1B6 Hs, C1B7 H 9 , C1BsH,o, 161 Infrared spectroscopic absorptions, of C1 B7 H'3' 161 B1 H 6,9 C1B9Hll, C 1B9 H'3' 160, 168 of higher boranes, 41 Index 203 Lithium, ethyl, 144 Reorganisation energies of aluminium hydride, 115 halides, 129 methyl,141 tetrahydroaluminate, 120 Selenate(IV) ion, hexachloro, 199 Skeletal bonding electron pairs, struc­ Magnesium compounds, Mg(A1Me 4b tural significance of the number of 139 in cage boranes etc., 152 MgH ,115 2 Sodium alkyls, 144 MgMe ,139 2 styx numbers, ofboranes, 46 Microwave spectrum of BsH9' 48 definitions of, 42 Molecular orbital treatments, of B H , 2 6 Symmetry elements, ofB H , 7 22 2 6 C H ,8 BsH9,48 2 6 Symmetry orbitals, of B2H6, 24 B6H~-,54 B12Hi2,56 Thallium alkyls, 137 Nuclear magnetic resonance spectra, Three-centre bonds, charge distribution l1B n.m.r. spectrum, ofB2H6, 12 in, 36 B2 H 5NMe2, 85 energies of, 62, 130 B4 H 10,35 Topler pump, 66 B5 H l1,37 Topological treatment of bonding III B6 H 10,38 boranes,41 BlOH 14,40 Transition metal carbonyl carbides, C 2BnH n + 2,163 FeS(CO)lSC, 146, 190 1H n.m.r. spectrum, ofB2H6, 11 Ru6(CO)17C, 146, 189 Me2HCCMei,181 Transition metal carbonyl hydrides, norbomyl cation, 184 [HFe3(CO)11J -, 121 organoaluminium compounds, 127 [HM2(CO)lOJ-(M = Cr, Mo, W), 121 Orbital correlation diagrams, for B2H6, HMn3(CO)lO(BH 3b 121 29 H2Ru6(CO)18' 121, 189 BsH9,49 Transition metal cluster compounds, B12Hi2,57 185 BHB bridge, 18 metal carbonyl clusters, 121, 188 BH2B bridge, 20 metal halide clusters, 185 linear XMX species, 196, 198 Transition metal cyclopentadienyl com­ (RLi)4,143 plexes, 192 Periodic Table, classification of hydrides Vacuum manipulative techniques, 64 by, 112 Photoelectron spectrum of B2H6, 27 Xenon fluorides, 197 Polyhedra upon which borane skeletons are based, 51 Zirconium tetrakis( tetrahydroborate), Potassium, methyl, 145 117 .