Tire rubber composition and pneumatic tire

A tire rubber composition, comprising:

• a rubber component comprising a diene polymer (1);
• silica;
• and
• a diene polymer (2),
• the diene polymers (1) and (2) each being a modified diene polymer obtained by reacting a component (A) and a component (B),
• the diene polymer (1) having a number average molecular weight of 110000 to 1500000,
• the diene polymer (2) having a number average molecular weight of 1000 to 100000,
• an amount of the diene polymer (2) being 2 to 25 parts by mass per 100 parts by mass of the rubber component,
• wherein the component (A) is an active alkali metal-terminated conjugated diene polymer obtained by polymerizing a conjugated diene monomer alone or with an aromatic vinyl monomer, in the presence of a component (C),
• the component (B) is a modifying agent containing a functional group, and
• the component (C) is a chemical species obtained by reacting an organic alkali metal compound with a compound represented by the following formula (1):
• wherein R1 and R2 are the same as or different from each other and each represent a hydrogen atom, a branched or unbranched alkyl group, a branched or unbranched aryl group, a branched or unbranched alkoxy group, a branched or unbranched silyloxy group, a branched or unbranched acetal group, a carboxyl group, a mercapto group, or a derivative thereof;
• and A represents a branched or unbranched alkylene group, a branched or unbranched arylene group, or a derivative thereof.